When we assemble an engine, one of the steps that I take is to test the head studs before we put the case together. It is a quality control step, and if one of the studs is slightly weak, I want to know it before assembly because it is a lot easier to fix before you build the engine. The procedure is fairly simple, and the tooling isn’t very elaborate. I bring my set to Colleges and show builders there the process in person. Here, in a few paragraphs and pictures, you can get a good overview.
Based on building several hundred engines in the past 20 or so years, the chances of getting a weak stud are low. About every 10th engine will have one. These studs were overstressed on disassembly or were overdone on a previous build. They look good on the outside, but the stud has been taken past its yield point.
Above, the test set up.The test is made easier with a high quality torque wrench, but it will work just the same with a beam type wrench. The small spacer on the arm allows the same tool to measure the longer top studs. The little tube is just a collar for the spacer, not required. The ends of the tubes need to be fairly true to the tube, the best method is turning them in a lathe, but careful work on a belt sander will do the same task.
Backing up a moment, I am going to assume that you have pulled and replaced all the studs that had hard tool marks from previous owners’ vice grips, and also pulled all the studs that have harsh rust pits. Mild surface corrosion is not an issue, and a missing thread at the top of the stud on the fine thread end isn’t a reason for rejection either.
Many years ago, I taught engineering labs at Embry Riddle in the Materials Department. People who have been through these classes know what a Tinius Olsen pull test machine is. For the rest of the gang, it is an immensely strong set of jaws pulled apart by a very powerful hydraulic system. Many of these systems can pull 50 thousand pounds without bogging down. A test sample of material is put between the jaws and very slowly pulled apart, while computers measure the length and power of the pull. This all happens at a very slow rate, pulling 1/2″ can be slowed down to take several minutes.
Instead of demonstrating the machine on expensive test samples, I brought in bundles of Corvair head studs. We pulled them apart in every class. It gave both myself and the students a much better understanding of the effects of corrosion and mechanical damage like tool marks. A used Corvair stud in fair condition may not look that strong, but it takes over 10,000 pounds of pull to get one to neck down and break. Because of this testing I have a pretty good idea of what is too much damage on the outside of a stud. But the testing in these photos tells the condition of the stud on the inside of it.
The test tube is a piece of .188″ wall 4130 tube, 3/4″ in diameter. I welded a washer on the bottom it give it a bigger footprint. I polished the bottom of this so that it doesn’t leave any marks where the base gasket goes. On the top of the tube there is a very high quality hardened washer and an ARP 3/8-24 nut. (This can be done with lesser hardware, but remember, the goal is to test the stud, to the strength of the test hardware.)
Above, the washer and nut are in my hand, the tube is viewed end on showing the wall thickness. The tube has a little stand welded on it from a 2004 test series where we measured how much the studs stretched when they are torqued. At full torque, the studs are almost .035″ longer. This is an outstanding design feature. The engine is “spring loaded,” and the studs maintain their clamping force through a very wide range of engine temperatures, and expansion and contraction cycles. Engines like the Jabaru have very short bolts that hold the heads on. Bolts like that typically need continuous checking, because even a slight amount of material compression under the head of the bolt will result in a loss of torque on a short fastener. Conversely, a long stud is comparatively immune to this. Certified aircraft engines have the heads permanently screwed to their cylinders for a number of other design reasons, but engines like the Corvair, VW and Porsche all use the long studs. These are part of a well calibrated system, and are the primary reason why you should not use an aluminum cylinder on a Corvair. Porsche 911s eventually had aluminum cylinders, but they also had uber expensive “Delavar” studs, with an expansion and contraction rate that was compatible with their alloy cylinders. Companies that have offered aluminum cylinders for Corvairs have not taken expansion into consideration. Making the studs thicker or stronger actually only exacerbates the issue. Corvairs are designed for steel or iron cylinders, and they have an outstanding record of reliability with them.
Coat the threads on the stud and the washer with ARP Ulta torque lubricant. Drop the tube over the stud, run the washer down and then the nut. Carefully torque the nut to 15 foot pounds. Noting the clock position of the wrench handle when you start, raise the torque to 20 pounds. Typically this will require turning the wrench about 45 degrees on the short studs, about 55 degrees on the long ones. Next, raise the torque to 25 pounds slowly. Now, the critical observation: It should take the same 45 or 55 degrees of rotation on the nut to get the new torque increment. There is an acceptable range, and you shouldn’t be too concerned about a variation of 15 degrees or so. But, if you have a stud that requires 100 degrees of rotation to go from 20 to 25 pounds when all of the others took only 45 degrees, you have found a weak stud, and it needs to be replaced.
Above, the tool on a lower stud, giving a better view of the auxiliary arm on the tube from a previous test. The arm plays no role in this stud check up. Note the plywood under the case. Don’t let the mating surfaces sit on a steel table, concrete or any other rough or hard surface.
A weak stud undetected is not going to lead to an engine failure. Typically, when a builder has a bad stud, he is torquing up his heads and notices that one stud turns way too far. This is the point where it would have been better to test before assembly. But even if it goes undetected at this point, the typical stud will not break, it just will not be clamping as tight as the others holding down the cylinder. In time this can lead to a blown head gasket.
Above, the task in action. The torque wrench is a $300 Snap On item, pricey, but an outstanding piece of quality. Ours is called Excalibur. If you ever meet an A&P mechanic and he has a pair of sunglasses or shoes that cost more than his torque wrench, be guarded about taking his advice. Paul Gauguin’s paintbox was more valuable than anything else he owned. The brush doesn’t make the artist, and the tool doesn’t make the mechanic, but it is a measure of whether a man considers his work a craft or just a job.
A Corvair is a very tough engine, and I have seen several of them fly a long way on a blown head gasket. The engine makes power on the cylinder even if the gasket is blown because at RPM the compression doesn’t have time to bleed through a tiny gap. A blown head gasket on a liquid cooled engine is a different story because it can mean a loss of coolant either out of the engine, into the crankcase, or into the combustion chamber. Liquid cooling is better in theory, but air cooling is better in practice. (A liquid cooled engine is less likely to ever blow a gasket, but if the discussion is about aircraft, you are mostly concerned about how the powerplant behaves after the event, not just the likelihood of the event.) In Corvairs, I have seen about 10 engines with blown head gaskets in the past 15 years. Almost all of these were caused by the timing not being set with a light at the static rpm. Only one or two were caused by a weak stud. Both of these causes are easy to avoid. Testing your studs before assembly avoids a small chance of a hassle on final assembly.
On final assembly, be alert for studs that take a lot more rotation to reach the rated torque value. When studs are torqued with ARP ultra-torque, we have done very careful tests to prove that you are getting the same clamping value at 26 foot pounds as a builder with light oil is getting if he torques the stud to 35 pounds. Use ARP, and stop when you get to 25-26 pounds. If you go all the way to 35 you are exerting a lot more force than required, and will actually be doing damage. Remember, you got into experimental aviation for the learning and adventure. Take pride that successful Corvair engine builders know a lot more about how engines are really built than any other group in experimental aviation.
Submitted for your approval, three stories I wrote in 2009, 2010, and 2011. For me, the human element of aviation has always been the focal point of my lasting love for it. I love the machinery, the creativity and the history, but the story of the individual, the person, is what intrigues me.
The stories here cover experiences of Astronauts, an Airline captain, and a Navy attack pilot. As a humble general aviation pilot, I will never fly into space, sit in the left seat of an airliner, nor fly in combat. Yet I hold that anyone who has built a single part, soloed a plane of any kind, or has spent years with the inner feeling that they were born to be part of the human panorama of aviation, can relate to the stories below.
The stories are not pleasant. An average day in the life of a professional aviator is one of reliable performance of duty. It is only under extreme circumstances that the nature of their character is revealed. I am a small part of one subset of aviation, and I will not face these same challenges, yet every experimental aircraft builder understands that he had to move beyond the fears that keep the rest of society sentenced to a mundane life, every soloed pilot understands the measure of courage required to go alone, and every pilot who takes a person aloft understands the responsiblity of the words “Pilot in Command.”
The 20th Century saw the discovery of both the North and South Poles, the Conquest of Everest, and the Development of Aviation from the Wright brothers through landing on the moon. These are fascinating stories of human courage and endurance. I have spent countless nights reading this history. Yet, the only one of these experiences that I can know some small part of is the story of flight. Every human challenge that was worth the title of adventure involved actual risk. We endow the title “hero” on the aviators at the pinnacle of our calling. But unlike the general public, we have some understanding of who our heroes are, and the costs they were willing to bear.
Why Bother? (2011)
I stood in my front yard two days ago to watch the last Launch of the Space Shuttle. It was very moving to think about the 30 years of the program, years that have spanned my adult life. “Land of the free and home of the brave” are the end of our National Anthem, but who personifies this? For my choice, I think of Astronauts. I have friends who work in the space program, and they all acknowledge that despite the risks, there is no shortage of very qualified people to go. I can remember the exact spot where I was in Florida the day The Challenger was lost. I have been to their monument on the hillside above the Tomb of the Unknowns in Arlington National Cemetery. Before their flight, they were briefed that their odds of perishing were between 1/300 and 1/20. They went anyway, not because they were gamblers, but because they know that some things were worth doing even if they brought a very high risk of death. From the Challenger monument, it is a short walk to JFK’s grave. In 1962 he answered the question of “Why bother?” on the subject of Space flight:
“But why, some say, the moon? Why choose this as our goal? And they may well ask why climb the highest mountain? Why, 35 years ago, fly the Atlantic? We choose to go to the moon. We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one which we intend to win.”
When JFK said these words, he only had about 400 days left to live. Almost all of the people reading this have far more time left here. Question is, what will you do with it? Will you succumb to a “Why Bother?” mentality that seeks out false paths because they appear to require less learning and thinking? If the goal of a seafaring captain was to preserve the ship, he would never leave port. If someone’s goal is to save money and learn as little as possible, I humbly suggest that experimental aviation will prove to be a very frustrating and potentially very dangerous path. If “Why Bother” is such a person’s personal credo, they are never going to get any of the rewards while simultaneously taking astounding unnecessary risks. “Why bother” is much better matched to watching TV than building and flying planes.
I am 48 now, and I am past the halfway point. The exact length of the trip and the destination are unknown, but the road of memories behind get inexorably longer. Is it time to slow down, and ask “Why Bother?” Of course not. Anyone reading this has been lucky enough to be born one of the .1% of the people on this planet who has any hope of building something with their own hands and flying it, a dream so bold that it was beyond the reach of any person who every lived on this planet a mere 110 years ago. I am smarter than I was last year; I have learned more, I have honed my skills in the workshop and in the air. Aviation offers a near limitless arena in which to expand your life, to willfully choose the difficult and rewarding over the easy and complacent. This increase of capability and control that is the reward for honest striving and effort is the only substitute I have found for the nostalgia for a fading youth. I will never run a 5:30 mile again, never do 50 consecutive chin ups again, nor a number of other physical milestones from age 24. But I am a much better craftsman, pilot and person than I was then. Experimental aviation is the setting where I will find out how much I can study, understand and master in my life, not how little. For anyone else who feels the same way, I look forward to reading anything you have to say, seeing anything you have built, and being there when you arrive in your plane to a welcome of people who understand what is worth aggressively pursuing in life.
Speaking of Courage* (January 2010)
I just finished reading Captain Chesley “Sully” Sullenberger’s book, “Highest Duty.” Most of what I read are biographies, and it is rare that I find one from an aviator that isn’t worth reading. Sully’s seemed particularly good. He tells his story back to being an airport kid in Texas flying a Champ. Many polished biographies elevate the subject above reality. Reading this book I felt that it did a good job of shedding some light on the life of an aviator who is likely far more than the pages convey.
If you were in the USAF or work in the airline industry, he emerges as a strong advocate of these callings. Sully does a first class job of explaining the mindset and challenges of the professionals who inhabit these parts of aviation. His sudden popularity says something about America, and he touches on this in the book. He has a Facebook site with 675,000 friends. A few weeks back I read in the New York Times that his book has been a modest success, selling 92,000 copies. The difference in the numbers tells me that people out there are looking for a hero, but they care far less to know how their heroes think or what forces shaped their lives.
Sully has a simple message inside his tale: Training pays off, even if it isn’t tested, living your life prepared is its own reward. Today, many people want to know the tricks and inside tips on any subject they encounter. They want the Cliff’s Notes on life instead of actually living. Sully, who recounts a lifetime perfecting his craft, offers a strong indictment of such a mentality.
He is quite clear that the terms ‘hero” or “miracle” do not apply to himself or to flight 1549. He explains why he feels that the successful outcome was the result of training, team work, judgment and a few factors going their way. He clearly states that he did not expect to die. However, Sully does believe in both heroes and miracles, and part of the book explains this by contrasting his situation with that of Captain Al Haynes and United Flight 232.
Above, Al Haynes
We forget a lot quickly these days. America has long forgotten the name and the flight number, but most people in aviation remember the Sioux City accident of 1989. It happened my first year at Embry-Riddle. The crash was examined in great detail. At the University, we had a good idea of how low the odds of survival were, and most people felt the term miracle could very well apply. The crew of UA-232 fought to find any way to regain control of the DC-10. Haynes and crew had little reason to believe they would live. Through astounding skill, composure and leadership, Haynes made the best landing possible. 185 people lived. Many did not.
Captain Haynes came to speak at Embry-Riddle not long after the accident. His face still had the scars of the crash. He had been hailed in the media, but I felt being at Riddle had to be different. Here, we had students who had some real understanding of what he had pulled off. In “Fate is The Hunter,” Ernest Gann’s preface states that airline flying is a kind of a war story, where “the designated adversary always remains inhuman, frequently marches in mystery, and rarely takes prisoners.” I went to see him up close, to look at a Captain who had just returned from battle.
I stood five feet away and watched Captain Haynes as he spoke to people. He was kind and direct, but somewhat detached, with a look as if his real thoughts were far away. I was young and impressionable, and clearly before me was a real hero. He had salvaged a victory for a certain disaster. To my eyes, he was now among the pantheon of aviation’s eternal stars. Perhaps the distant look in his eyes was appropriate for a man who was proven in a field where all prepare for their battle, but very few are tested.
Fourteen years later, Captain Haynes is the guest speaker at the evening program at the Theater In The Woods at Oshkosh. Here, at the center of the world of flight, his star has never been diminished. The outside world has forgotten and moved on, but here, inside, the faithful fill every seat. It has been a full day of exciting things, but the people are now settling down as they take their seats. They will soon listen to a serious subject from a man known for a heroic deed. The last time I saw him I was part of a very young group, just at the start of our time in aviation. I looked around and saw where my classmates would be in another 20 years. The people around me had most of their flying logged away. Their gray hair and modest dress told outsiders nothing of the adventures these people had seen. They had led the strenuous life of challenge, and known its rewards…and perhaps its costs also. I looked around and guessed that many of them had lost a close friend to an accident. As soon as I formed that thought, I realized to 14 years later, I too, was in this last group.
The presentation was a technical one. Captain Haynes had made it his duty to frequently speak on behalf of preparation, teamwork, training, and when your test comes, not losing yourself or giving in to fear. He had spent the previous years communicating this, never accepting a fee or any kind of reward. They played the ATC tapes and slowly brought us to the moment of the crash. The audience was moved. Many people near me sat quietly wiping away tears in the dark. Perhaps they were thinking of friends, now long gone, wishing their friends had been luckier and had a man like Al Haynes for an instructor, a mentor or a co-pilot.
At the end of the presentation, a man, looking like he could have come from any EAA chapter in America, stood up. He struggled to gather himself and start a sentence. After a moment, in a choked voice, he got out “I just want to say I think you’re a hero.” A round of applause broke out, but it was quickly put down with a wave of Captain Haynes’ hand. He addressed the man directly. In an even voice with very little emotion, he said “I am not a hero. 112 people on my flight died. Please sit down.”
After the lights come up and the people drift away, I sat with Grace. It was very hard for her. I have little memory of the Burn ICU, but Grace had sat there all day, every day, for weeks. The cost was not abstract to her. Of all the people in the theater, she knew what the last moments of many of the 112 had looked like. After some time, we got up to walk out to the parking lot. As we went past the back of the theater, Captain Haynes was standing there with a few of the people from the stage crew. Grace went over to personally thank him for the evening. I stood about five feet away.
The 14 years had not been kind to Al Haynes. Both his son and wife had died. His daughter was terribly ill. I could not hear what he was saying softly to Grace, but he had the same look as he did in 1989. He was there, but detached. His story reminded me of a Greek Tragedy, no matter how noble his actions, fate struck people in his care.
A different man might have written it all off. Given up, and assigned the events to bad luck, a curse or even a vengeful God. I don’t think it is too much to say that Al Haynes would have none of these outs. He is a man, Naval Aviator and Airline Captain. He has a lifetime of being in command, evaluating the circumstance, minimizing the risk, and taking responsibility for the outcome. Such a man couldn’t easily shrug off or rationalize away the loss. Right or wrong, he is the kind of man who would only see it as his personal responsibility, and this is the reason I will always be able to say Al Haynes is my hero.
*Speaking of Courage is the title of a chapter in Tim O’Brien’s 1990 novel “The Things They Carried.” The writing is an unflinching look at sorrow, love and personal responsibility in the wake of tragedy. It is a profoundly moving work of philosophy for people who do not trust easy answers to hard questions.
Friday Night, November 20, 2009
Just as I am getting used to Daylight Savings stealing an hour of the evening, the days are getting noticeably shorter here. During the week, our clock revolves around 4 p.m. This is last call to drive the ten miles into town to the Post Office with the days mailings. In the summer there are hours after this to eat dinner, mess around in the shop, and casually pre-flight the Taylorcraft before going aloft for the last hour of light. But now the casual hours are gone. I drove back to the airport with an eye on the low angle of the sun, maybe only 50 minutes until it sank.
I pushed the plane out to the edge of the runway. I stood there for a minute, not a single person was in sight. Just the sound of a circular saw from somewhere up on the North end of the field. The visibility was poor, there would be little to see, but I had been out the past 6 days in a row and today would make a week. Kind of a pointless exercise, going up for 20 minutes to round out a week, frivolous really. These are the things you think of on the ground, by the time I am running through the mag check the pros and cons of going aloft are forgotten. I orbit the airport in big slow circles at 70 mph, engine at 1700 rpm, just licking over. It all looks gray and colorless. Was it noticeably greener a week ago or is it just the haze setting the mood?
When I touch down, the landing gives me the same feeling as finishing a chapter in a captivating book: Looking up from the last page with the powerful feeling that you have just been somewhere else. Taxing up to the house and shutting off the engine I have the same sensation.
Three or four minutes later, our EAA chapter president returns from being away all afternoon. A 180 mph pass at 10 feet signals the arrival of his RV-7. As he flies the landing pattern, I walk the 400 feet up to his hangar. We arrive at the same time. He has an unexpected passenger, Dave, our airpark president. Dave has his own RV-4, and I have never seen him as a passenger in any plane. In his youth he flew an A-4 from the USS Forestal into the most fiercely defended airspace on the planet. The black and white photos of him in his hangar are of a much younger man in a flightsuit with a helmet under his arm. He has the same grin today, but you get the impression that big chunk of Dave’s youth, and a good number of his friends, only exist in his memory after 1967. Either way, he looks really out of place in the right seat, or in any side by side aircraft for that matter.
The moment fits the gray haze: Pat and Dave have just returned after delivering the RV-9 of a fellow EAA member. This man has also taken up residence in Dave’s memory. He was killed this summer, along with another friend, in an unexplained Glasair crash. One moment they were flying a low pass over our airport, a little dog leg to say hello on their way home. The next day Pat found the wreckage in the woods a few miles away. They delivered the RV-9 to the man’s widow, who was very thankful. The plane was just finished, and it is magnificent. She is keeping it in storage until next Oshkosh. The man was an EAA member for 30 years, known in some circles. She would like it judged posthumously. She had said some moving things to Pat and Dave, but at the moment we were standing out on their ramp with the sun fading, neither of them felt up to relating her exact words.
Dave started a sentence twice, but after a pause he didn’t finish. Pat spoke about a guy he knew in flight school, lived 3 doors down, a Marine. Pat heard about his crash on the news, and walked out his front door in disbelief. Seeing the black cars gathered down the block took away the doubt and hope at the same time.
An engine starts at the far south end of the runway. It is Dan Weseman and the Cleanex. After a minute of run up, he roars past us, 50 feet at midfield. Dave looks at Pat and says “Let’s get him.” The RV-7 turned around and back on the grass in seconds. Dave pushes out his RV-4. Their take off alerts the airport, and several people drift out of their hangars to sit on the grass and watch.
If flying at most airports is an elegant ballet, flying at our airport is Mixed Martial Arts. The furball is formed, broken and formed again over our heads at 1500′. Between the sounds of wide open engines, the radio chatter barks out from the base station in Alan’s hangar. In minutes they are joined by Bob in an RV-4 from the North end, and then another RV-7. In the sky they turn impossibly tight. You can’t always make out who is on top, or even who is who, until a glint of the sunset differentiates a painted wing from a polished one. It is hard to believe that the same airport was dead silent 20 minutes ago.
One by one, they drop out and land. Pat is first, and has most of a beer finished as Dave rolls up. Bob is the last to break off, leaving it where it started, with Dan alone in the sky doing a few last slow rolls. The mood is transformed. It was 10 minutes of really being alive. Dan landed, rolled out in front of us, turned a smooth 180 and taxied back towards his hangar, his home, his family. He was close enough for us to see his expression, but he didn’t look over. In the air, he had been far closer to the other pilots. The light is gone now, and the day is over.
A few more words, and the hangar doors are shut, and people drift away. Walking back to my place, I pause in the dark to watch Dave walk out to his pickup. He had been the one to say “Let’s get him.” This had been Dave’s doing, perhaps his ritual. A little farewell to a man whose memory had just been carefully and lovingly wrapped up for safe keeping. It was now stored beside the others. A resident, final age 58, joining a group of younger men, some of whom arrived 42 years ago. Although I’m sure he cherishes them all, he probably doesn’t visit with them often. Dave is too full of life for much of that. Besides, one day he will have all the time in the world to spend with them.
William Wynne, 2009
Big news on Scottie Blankenship’s Corvair-powered Highlander: on January 10th, at the Just Aircraft factory (where Scottie works), he ran his Roy-bearing engine for the first time — on the airplane. It fired right up, and the wonderful sound and smoothness of the Corvair dazzled a lot of people.
Scottie still has a little work to finish up the airframe, but the first Corvair-powered Highlander will be in the air soon.
My 3-liter engine is at Roy’s now, and I expect the engine and I will be at his next hosting of the Corvair College. Though my Highlander is still well behind Scottie’s, I’m building every day, so I’m making steady progress.
The blog is a fine idea. Thanks for your continued good work.
Richard Holtz, Highlander builder, alumnus of Corvair College #20
Thanks for the photo and the update. Hopefully we’ll see this bird at Sun ‘N Fun 2012?
Please give our congratulations to Scott. Looks like and outstanding job. Send us the word and a photo when the first flight happens.
DO YOU KNOW YET, WHERE YOU WILL BE RECOMMENDING THESE NEW HIGH VOLUME OIL PUMPS BE USED?
Flying Zenith 601 with 2,700 cc Corvair, Corvair Colleges alumni
This pump is only recommended to builders using a Weseman bearing. Roy tends to use stock pumps with his bearing. Send us an updated flight report on your airplane and some fresh photos when you have a chance.
I’m no guru, but oil is a subject mechanics really toss about. I’ve heard a million reasons for or against a certain oil, oil pressure, volume, SAE grade, etc. I sold Amzoil for about 2 years and my hardest sell was to aircraft mechanics. I knew it was tough as nails oil, and it could really take the punishment of aircraft engines. I ran it in everything, cars, boats, motorcycles, and I could not convince the aircraft owner to put it into aircraft applications. I think that opinions are like noses, everyone has one. Aero Shell was what they wanted, and they were not to be swayed. Shell is a very good lube, but I think Amzoil is a tougher product.
Perhaps the fact that they are more armchair quarterbacks, than actual pilots who assess the real life issues facing piloting a homebuilt. Besides, this heavy duty oil pump was accepted and ok’d by Scoob E. That’s enough for me. William be well.
Mike Festa, CC20
Thanks for your comments. As you’re an airline mechanic, I hold your opinion in high regard. We flew a lot of hours on Amsoil and it works great in a Corvair. I want to caution builders to NEVER use Aeroshell in a Corvair. It has no zinc phosphate in it, a required element that is protecting the cam and lifters in a Corvair. Our favorite oil remains Shell Rotella T 15W40.
I enjoy reading your writings, philosophy and about your experience. I feel and work very much on the same principal as you, and relate to your philosophy because I feel we are driven by the same things, and also our need to learn how and why. You are doing an excellent job of getting the word out on your work, and I while I am still in the early stages of learning about and building my Corvair conversion, the more I learn, the more I know I have made the right decision for me and my project.
Thanks for your kind words. I write the stuff from the heart. It doesn’t resonate with everybody, but the style is honest and a number of people, like yourself, appreciate it as an addition to the technical expertise. Keep us posted on your progress.
Is this the same high volume pump I saw at the last College in November? I wasn’t that familiar will all of the parts but I thought I saw a machined deep case like the one in the picture at your table along with the carbs. It was a nicely machined piece.
Gary Burdett, 2,850 cc CH 750 builder, CC #21 alumni
Yes, we had the prototypes at CC #21. The Colleges are often the first places we display new ideas.
Brian Manlove, heading to CC #22, comments on High Volume Oil Pumps:
Mom’s Singer sewing machine, circa 1956. I was 4. Totally disassembled. She said I got screws loose that she could never budge. She promptly bought me a nice Erector Set… Which lasted until the lawn mower a few years later…
This is a great site. Thank you for taking the time to put it all together.
I read through this article on the balancer with interest. I really appreciate the pictures and your detailed explanation. This gives me a much better picture of what is going on, on that end of the engine. My balancer is stock that came with the engine. I had thought of using it but I am now having second thoughts and will probably replace it with a rebuilt. Is there a good way of telling if the balancer is good?
Jon Coxwell, CC#20, GN-1
Thanks for your coments. My New Year’s Resolution this year was to swear off watching anything on a television set. As a positive substitute, I’ve been working on our aircraft a little bit and reading a lot more. I just picked up a copy of Laura Hillenbrand’s New York Times Best Seller “Unbroken,” the World War II biogroaphy of Louis Zamperini. Chapter 8 starts with describing a B-24 mission out of Hawaii on January 8, 1943. I believe it is describing your father and his crew. The note is a few brief paragraphs, but I’m sure it will be of interest to you. it
On your balancer, if the rubber is extruded above the surface of the metal, I would not trust it. Rebuilt balancers have a eurethane type material in place of the rubber. Dale Balancers have a four-digit serial number stamped on them and two witness marks to align the inner and outter part. If you have one of these, it is good to fly.
The billet crank, for the reasons stated, looks like a very promising approach. The methodical and careful approach to R&D is what impresses. At the same time I can appreciate that the standard 164 Corvair is more than adequate for an airplane such as the Pietenpol that I’ve started on.
Harold Bickford, Manual #8606
The best evidence we have available suggests you’re right. If someone wanted to use a billet crank in a Pietenpol, I’m all for it. If someone chooses to fly another aircraft on a stock crank, I’m all for that as well. As I stated in the post, I’m here to present the data as we know it and let each builder decide for himself what makes sense on his own aircraft.
Thanks for your responses regarding my motor mount. I am still practicing my gas welding technique. It has to be good if I’m going to attempt to tack-weld to a spool on a wood table top!
On another note, I was wondering if you could comment/report on the status of the turbo set-up. Even though I am 90% set on the 3L option for the heavier Rebel (about 925 lbs. empty), turbo normalizing on a bush plane seems like a good match (max take-off power even at high density altitude, etc….). Roy hasn’t even started on my 3L conversion yet, so it’s not too late to change my mind.
Rob Schaum, Murphy Rebel
Here’s the good news: A 3 Liter engine has the dished pistons in it which allow later turbocharging should you choose to upgrade to that. We had very good results testing the compatiibility of turbos and OT-10 cams. There are a few small changes to turbocharging an engine, but they are all external on a 3L. Anyone building a 2,850 or a 3L engine is in a good position to upgrade to a turbo later if they choose to do so. It will not require changing anything internal on the engine.
Back in the day when I worked in a shop remanufacturing Allison transmissions we used TimeSerts. Never saw one fail. Did however see some Helicoils unravel during disassembly for whatever reason. Perhaps not adequately installed? But none I saw failed in operation, only disassembly.
(I am a mechanically inclined PP-SEL with some taildragger time; dedicated observer & fan but not a builder at this poin t- but /only/ because of present financial and time constraints. Have pretty firmly concluded that Corvair would be the best/only choice for me if/when I build. Kudos to William for his philosophy & zeal in encouraging this most sane of alternative engines!)
Dear Mr. Elk,
Thank you for the comments. The number one thing that helicoils and some time-serts have a problem with is having excessive carbon hanging out on the end of a sparkplug thread protruding past the helicoil into the cylinder. When such a plug is removed, the carbon will occasionally jam the threads and back out the helicoil. For this reason, I like time-serts in sparkplug holes on Corvairs more than helicoils. However, helicoils do a darn good job in places where the bolt will not be removed and replaced frequently.
I like the Panther construction concept. Is there any new info on Ed Fisher’s Fleet or Zipper designs?
Thanks, Pete Chmura
Ed Fisher is not currently actively working on either of those designs.
Great work. This site looks good — Larry Hatfield, #21 CC alumni, 3L 750 builder
Thanks for the kind words, Larry.
Your new blog is the perfect forum for this kind of information sharing. It is so easy to get distracted by the noise and chatter of the online discussions that seem to attract strong (but often uninformed) opinions from self-proclaimed experts. I continue to appreciate your practical approach to helping builders follow a proven path to their first flight and beyond. Thanks, William. Now it’s back to the shop so I can see you in the air in 2012!
Larry Winger, California, CH 650 2700 cc/Weseman bearing, engine ran at CC #18
I thought you’d appreciate the photo above taken during the housecall I made to you after Corvair College #18. Keep us posted as you close in on your first flight.
Becky Shipman, 2,700cc CH 650 with Weseman bearing, comments on Chinese crankshafts:
Part of my job for a multinational corporation is to train Chinese engineers to maintain and operate coating equipment. It takes a while to get them to understand the importance of maintaining tight tolerances. I think I’ll go for an original GM crank nitrided.
The original GM crank nitrided with a fifth bearing is the most popular combination that people are building for their Zenith aircraft. Although there are a large number of 601/650s flying without a fifth bearing, many of these people plan to upgrade to a Weseman bearing. We recommend that everyone with a STOL airplane utilize a 5th bearing because they can generate large asymmetric loads at high angles of attack.
Dan Branstrom comments on Chinese Crankshafts:
I concur with your evaluation of Chinese manufacturing. They are capable of making some excellent products, but quality control is not their strongest suit. Price is their strongest motivation, and, when they compete for business with other businesses in China, their margins are often paper thin.
China has a vastly higher number of engineers than we have here in the U.S., but in their move from what was basically a feudal, agrarian, society before the revolution, to a much more modern and still economically controlled society, there have been a number of shortcuts that have been taken. It shows up in quality.
It’s the wild west there. There are no standards and they don’t use W. Edwards Demings’ quality control principles in many of their products. Caveat emptor.
I read your comments with special interest, aware that your mother and father worked a great deal of their lives in mainland China before the revolution. Your international background, hailing from an American family working in China born in India, gives you a unique take.
Rick Lindstrom, contributing editor of Kit Planes Magazine, 2,700 cc 601 builder and pilot, comments on Chines Crankshafts:
Years ago I worked for a computer manufacturer that had our circuit boards built by relatives of the CEO in China. These boards were plagued with compatibility issues, and I headed up the service organization charged with making them operational. This is where I learned a lot about the Chinese philosophy of manufacturing. Two things still stick out.
The Chinese are VERY frugal, to the point of using a known incompatible component until it’s gone from inventory. The silk screened revision number might be correct, but the mix of parts on the board was anybody’s guess.
And they also have a common saying when dealing with westerners. It goes “You can ALWAYS fool the foreigner!” We think this is unethical. They think it’s good business practice.
I keep these two things in mind whenever I purchase anything. I’ll pay double or triple if I can avoid the serious quality issues inherent in Chinese hardware.
But, I still like Chinese food.
Thanks for your comments. We included the above photo with you in the center flanked by myself on the right and Michael Heintz after you won the Best Engine Installation Award at Copperstate in 2007. We also love Chinese food. Our local restaurant is owned by a family that emigrated from Kowloon. When you think about it, the food they make now is made in America.
Dan Glaze, Corvair College graduate with running 2,700 cc engine comments on Chinese crankshafts:
Well said William, my trust is in your vast experience with the Corvair.
We’re here to present the facts. We trust your ability to decide for yourself based on the data we present.
Ron Lendon, 2,700 cc, Roy bearing equipped, CH 601, 1st engine run at CC #17, also writes about Chinese crankshafts:
Thanks for taking the time to provide a well thought response to the crank issue. Hopefully those who need to know this story will read and understand its full meaning.
Your thoughts on this carry some weight. The fact that you work for the engineering branch of General Motors and understand international manufacturing makes your recommendation noteworthy. Looking forward to seeing your airplane airborne this year.
Talked to Ken P tonight and learned about this blog. Looking forward to lots of good info being passed around.
We couldn’t have gotten this started without Ken’s help. He’s been an unbelievably productive and encouraging friend for many years.
Nice blog site! .. I’m very glad to see you back on the web with a Q&A forum that includes pics. It’ll be a great resource to builders and Corvair flyers alike. I just passed 80 hours last weekend on my Corvair-powered Zenith CH650 and the engine I built seems to produce even more power in the past 30 or so hours .. I assume that’s because it was finally breaking in? I have yet to re-pitch my Warp drive prop just yet as I’ve been enjoying flying too much on any nice weekends. At 3000 rpm I get 115 mph indicated on these chilly days here in Indiana .. and that’s at 8.5 degrees of pitch.
By the way, I firmly believe the Corvair engine is a perfect match for my home-built aircraft and delivers outstanding performance for an engine that I built and can maintain going forward. Thanks again for launching this site and the support you will provide here.
Dave Gardea, Flying Zenith 650
Great to hear from you. Thank you for the progress report. If you can e-mail us a few current photos, we’d like to do an aircraft update on your plane here like we did with Andy Elliott’s. A YouTube video link also would be greatly appreciated.
I just found out about the blog; guess I have been living in the past. The content is great and I look forward to learning from the discussions. Love the philosophy!
Blaine Schwartz, 2,850 cc Zenith 750 builder from Texas
Looking forward to seeing your engine fire up and run for the first time at Corvair College #22. Thanks for the positive word on our new efforts.
These valve covers look really nice. I wish mine were powdercoated, but I didn’t even think of that, back in the day.
I think this blog is a great idea. It looks like this will be a great forum to record your vast knowledge about all things Corvair.
Phil Maxson, 2,700 cc/Weseman bearing, Flying 601XL, New Jersey
I watched the YouTube video the other day of your airplane flying over Daytona Beach. It had 30,000 hits on it. You’re a movie star. Send us a few new photos and an update and we’ll write a Flying Planes post about you like Andy Elliott’s.
It’s great to be connected with you in this way, looking forward to staying in touch and up to date!
Dr. Steve Mineart, Flying Zenith 601 with 2,700 cc Corvair
Just like Phil, we need updated photos of your aircraft, preferably some in-flight, and word of your adventures to date. Just email it them to WilliamTCA@aol.com. Looking forward to reading it.
Hi William and Grace,
Glad to see you get this site up and going. I always liked reading the daily Q and A on the other site. Flying the Piet every chance I get a warm enough day.
Randy Bush, Tennesee, builder and pilot of Miss Le’Bec, a 2,700 cc Roy bearing equipped Corvair powered Pietenpol
Great to hear from you. You’re one heck of a tough guy flying an open cockpit plane even on warm winter days. Hoping to see you at Brodhead again this year.
William and Grace,
It’s great to have a single-point resource for open discussions on the Corvair conversion. Have been following “The Movement” for several years and am now building a CH650 which is slated for Corvair power when the time comes. However, I must say that my enthusiasm was curbed a bit after hearing of Mark’s crank failure but I remain optimistic that this conversion will continue to evolve into a reliable alternative power solution.
Thanks for all of the expertise and insight that you so generously share with the rest of us. Looking forward to following along with hopes of sharing something meaningful in the future.
Sonny Webster, Magnolia, TX
Thank you for the note. We’re going to cover a lot more of the successful flying Zenith aircraft, to give people a more rounded view of how many successful flying aircraft there are out there on Corvair power, particularly Zeniths. The notes above include 3 guys who are out there flying the Zenith/Corvair combination you’re building. Given all the data, most builders agree it’s an excellent combination. Hope to see you at CC #22.
Hi William & Grace
I really like the new Corvair Communication Center, you all did an oustanding job setting it all up.
Building Wagabond w/ Coravir Power, first engine run CC #20
Great to hear from you. We had a fanatastic time with you at Corvair College #21. Looking forward to seeing more of you this year. Keep up the good work on your project and please email us photos of your project.
Good to see you back, missed you over at Corvair list. Buttercup is sleeping nice and snug, hope to have shop room in a month. Looking forward to a CC at Roy’s place.
Joe Brown, Merrill, WI
Good to hear from you. I was just saying to Roy that the housecall we made to your place may very well have been the northernmost one I’ve ever made in the U.S. Good to hear that your plans for a shop are coming together. There are many people who would like to see you put the rest of our old Buttercup project together and demonstrate how well that combination will work. Please keep us posted on your progress with photos.
Hi William and Grace,
I would post some pictures of my Dragonfly/Corvair but I am not sure how to do that on this blog. I am not a blogger does one have to join a group or something?
Since you’re a real life rocket scientist, we would have figured you knew all about blogs. You do not have to join or subscribe, you can just come here and read and send us photos to our regular email address, WilliamTCA@aol.com. This blog has a notification feature that will let you know when we have something new on here if you click on the RSS link and subscribe. Looking forward to hearing of your first flight.
Welcome back !
Just saw Pat P’s note about this site on Mark’s list. Glad to see you back online.
Thanks for the encouraging word. Tune in, we’ll have a lot more to say here.
Good news is that you are doing this blog site. I feel like my principle information source is again available to me. My 2850 cc is mounted and waiting on me to finish up the remaining tasks of completing the the Sonex, such as wiring the panel and painting. Just a couple of more months!
Clarence Dunkerley, Cleanex builder with running engine, CCs #19 & 21
Great to hear from you. Watching you and your brother work together at CC #21 to get your engine up and running was fun and inspirational. I got a message from Sensenich the other day, so I suspect your 54×56 prop is ready to go. Looking forward to seeing your bird in the air this year.
Congratulations William this is a wonderful blog site. It will be a real asset to Corvair builders and flyers.
Carroll Jernigan, builder of the first engine to run at CC #17
Great to hear from you. I used the flywheel tool you graciously gave to us just the other day. Brought back nice memories of having you at CC #17.
N319WF – Reserved
The new blog is great. I hope to be in your flying section soon!!!
Great looking Blog William. Great to hear from you!!!
Jeff Moores, Merlin builder with running Corvair, Newfoundland, Canada
We thought you’d like your airplane being featured in the Stainless Steel Exhaust article. Keep us posted as you close in on flying.
The following photo series is of testing a new High Volume Oil Pump that we had made. The assembly and testing covered about 5 hours on Friday night. When I was in my 20s, I used to make a point of donating 10% of my week’s pay to Anheuser-Busch corporation on Friday night. In the past 2 decades, I have found more productive things to do with weekends. Years ago, people saw how much time I spent at our old hangar and often said that I practically lived at the airport. After Grace and I were married, rather than trying to get me to come home from work earlier, she came up with the solution of moving the house closer to the hangar. For the past 6 years they have been 10 feet apart. Our hangar is 40’x50’, but I do most of the work in the adjoining 15’x30’ shop seen in the photos. Our hangar is a basic metal pole barn without insulation. The workshop is fully insulated and got an older central heat and A/C system installed last year. (We have a neighbor in the HVAC business who needed a Warp Drive prop.) Although we live on a little airport, working in the small shop next to the house gives me the same feeling I had when I first got started building planes in the garage behind my house at 1235 International Speedway Blvd., Daytona. Working in the shop makes me think about all the other builders out there working in their garages, basements and workshops, all the people enjoying the hours creating their plane with their own hands. No matter how diverse homebuilders are, they all have this in common.
Here is a shot of the basic unit. A high volume pump is basically a longer set of gears with some type of extended housing. The extended gears are from a small block Chevy V-8, and they are identical to a Corvair’s except they are .400” longer. The next time some brilliant guy in your EAA chapter tries to tell you that Porsche or Franklin designed the Corvair engine, you can ask him why he thinks the oil pump is interchangeable with a V-8. The Corvair is 100% Chevrolet engineering.
The extended housing on high volume pumps is usually a two piece affair that his held together with roll pins, it can be a little tricky to set up, and it does have some pumping losses from a less than perfect fit in the assembly alignment. It also has two gaskets in it. Above you can see that our housing is a one-piece bowl-shaped unit, CNC machined. Instead of aligning itself on roll pins, it centers itself on the two shafts, which are stabilized by the housing. This is not a new concept, this style had been made before by Corvair car racing guys. However, our unit was sized from scratch, and independently developed to serve aircraft guys. It is self aligning, has minimal pumping losses, and only has one gasket.
If you have been around Corvairs only a few years , this is a tool you may not have seen before. I built it many years ago to test oil systems. It is the back half of a Corvair case with a little sump added underneath. It has plugs welded in a lot of places to seal it, and the gauges are set to read oil pressure before and after the bypass. It has a valve to allow mimicking any bearing clearance and oil flow requirement. This part is actually a rare “RL” case from a 180hp turbo Corvair, but it is special for another reason: It flew several hundred hours in our Pietenpol. Over the years, we have tested many cases on this unit. After we moved to Gold Oil Filter Housings, we stopped working on rear oil cases for builders because most Gold Oil Systems use our replacement oil cooler bypass valve built into the Sandwich Adaptor. This unit was very good at detecting a marginal stock oil cooler bypass, in addition to testing oil pumps.
Over the years, I have made lots of pieces of custom testing equipment, because testing is the most important element that we do. Many people have an idea about making a part. If they have time and money, or they are amateur CAD guys, they can get a machine shop to make the part. Some of these will function, and a still smaller fraction will work with other required parts in a way that fits in the final installation. Some of these parts will actually pass basic testing. But the real testing requirement is not showing it will work, but aggressively trying to find the way the part, or under which circumstances, or in which combination it will not work. Few people understand that this is the real focus of testing. Most people who conceive of an idea, defend the concept, nurse it through manufacture, and then start testing it have a big emotional attachment to it. At that point, they believe in it. They have a very hard time trying to develop any test that will show the part or concept to be deficient or vulnerable. For testing to be of any real value, you have to run it as if it is being directed by your worst enemy, your ex-wife and her mother, and the guy at work who thinks homebuilt aircraft are crazy. For the period of testing, you have to pretend that these people have PhDs from MIT and Cal-Tech, and they want to find any flaw in your idea. You have to really let go of any emotional attachment to the concept’s success. This is really what running an effective test is all about.
Adhering to this over the years, we have tested a lot of ideas that never saw the light of day. All of the things we do make were refined by the process I just outlined. Our evolution in the development of the engine and installations was never hampered by an emotional attachment to the way we were doing it. Once a month or so, I will get a guy on the phone who will say something like “well you used to do it that way” referring to the set-up he is planning on using in his plane. He saw in an old photo on our Web page, and is yet to understand why it evolved. His attachment is understandable, it’s how we did it once, and he doesn’t see the forces that drove the evolution. I talk a lot, but I am also a very keen listener, and in the conversation I can hear if they guy has an emotional attachment to the old way, and if he is resistant to the logical reasons why it evolved. You don’t have to build your Corvair the way we do, but when evaluating your choices, be very cognizant of the emotional attachment factor creeping in and not letting you truly evaluate the merits. Homebuilders by their very nature arrive in the field wanting to do something different. They are reluctant to be seen as conformists. This is a good concept, but it can also work against the practical goal of completing the plane. If 10 new guys all look at the logic of why we build engines the way we do, evaluate it, and then choose to build their engines that way, this is not a sign of conformity, this is critical thinking leading many people to the same point. There will always be some guy on the Net who criticizes this and tells everyone how his engine is going to be totally different, that is once he gets started building it. 20+ years of working with homebuilders has taught me that the odds of that person flying anything are microscopic. But it isn’t primarily because his idea is bad, actually the Achilles heel of his whole concept is that It is emotionally driven by a force that has very little sustenance in it, the concern for what other people think of you.
In the background, a selection of oil pump gaskets in different thicknesses. This is how Corvairs set the pump clearance. After test fitting them, and checking for a slight drag on the pump while turning it, I settle on a .007” thick gasket and give it a light coat of spray copper before sealing it up.
Here is the unit all buttoned up, Yes, I ate dinner at the workbench.
The drill bit is pointing to the pressure regulator bypass hole. It has to be opened up when you install a high volume pump. Otherwise the pressure will be very high until the oil temp is thoroughly warmed up. The enlarged hole allows the bypass to work with cold thick oil. Without enlarging this hole it might take 15 minutes of running on the ground on a 40 F day before the oil settled down to its normal regulated pressure. Before this, an increase in rpm will raise the oil pressure. On very cold start ups you want to watch this, because even with the hole enlarged it is possible to have the oil pressure exceed 80 pounds by carelessly revving the engine to taxi it while the oil is still cold. Give the engine a chance to warm up, don’t be in a rush. Oil pressure spikes are very rough on the drive system running the pump. This is true of almost all engines, not just Corvairs. People don’t talk about ideas like this with the buy-it-in–a-box imported engines because they just wanted to buy something and use it. Since the primary motivation with Corvair builders is to learn while creating, we talk about things. Most people are happy to just have things, people attracted to the Corvair were the ones who took apart the toaster at age 10, because for some of us, we need to know why.
This plug holds in the spring and the pressure regulation piston. Make sure your piston is polished and the bore has no burrs left over from enlarging the hole. I use a copper crush washer for the gasket. I use the higher pressure spring from Clark’s. The wrench size is 13/16” but it has small fine threads, so don’t do more than 15 foot pounds or so. I do not safety these, and I have never seen one get loose. This plug is shiny because I nickel plate them.
Above is the unit in action. It is being driven by an electric drill on a priming shaft, just the way we prime the engines at the Colleges before we run them. After running through the system, the oil is returned to the center of the case by the 3/8” aluminum hard line on the right; it is entering the case where the #1 cylinder was. Notice that you can actually see the oil stream flowing in the photo. From there it goes back in the bottom of the case and is sucked into the pickup again. The new pump flowed like a river, even at very low rpm. We are going to let it run for a long time in the shop this weekend, with the drill trigger held down with a zip tie. It will be noisy, but I have my sister’s old 1970s stereo that she bought with babysitting money in the shop, a hold over from when people cared about sound. 120 watts, Ohlm speakers and an extended cut version of Exile on Main Street and I will never notice the sound of the oil pump rig running all weekend. Monday we will take it apart and look for any wear on the inside.
Grace and Scoob E were out in the shop helping with the project. Above, Grace ran the drill during the set up tests. This rear cover will have a Gold Oil Housing on it when it is finalized, but for testing, I have it set up with one of our old style oil top plates from the 2004-2007 era. You can see the built-in pressure gauges in this photo.
It wouldn’t be Friday night without a little fun. Our neighbor Roger was having a cookout and a bonfire in his front yard just down the runway. We missed dinner, but arrived in time for the relaxing around the fire with a beer phase. Most builders know that the one pound cooling fan on a late model Corvair car is made of magnesium. We brought one down and after warning those present, tossed it in the fire. It ignited after a minute of warming up. For five minutes you could have seen our airport from low earth orbit. The camera doesn’t do the event justice. It illuminated the entire southern end of the airport; you could have read a newspaper 500’ away. At most airports this would have brought firefighters, hazmat people and the news media. At our airport it brought more people with beer. As a little kid, I played with matches, built tree houses, took apart the toaster, made go-carts and was known on a first name basis at the emergency room. My test methods have gotten a lot better than childhood forays into chemistry, but my incessant need to know remains the same. I accept that the majority of people in life have a consumer mentality that tells them that simple possession is the route to happiness. For the rest of us who know that our path to happiness is learning and creating, we have the Corvair movement. The Harley Davidson slogan, “If you have to ask, you wouldn’t understand”’ is a modern version of George Mallory saying “Because it’s there” about mountaineering. The first statement has become something of a cliché, and many of the people saying it are concerned with what others think, but Mallory was deadly serious that he was not going to lead his life by the mundane concerns of others. My mother taught us to be civil to everyone, but even as kids, there was a clear distinction between always being considerate of others, and leading your life by what other people think. It was an important inoculation that protected me, especially in my teenage years, from peer pressure and the things it leads adolescents to. In the long run, it made me comfortable following my own path, with little concern for what the larger group thought I should be doing. The Corvair movement is a reflection of this, and if you feel the same way, I say “Welcome aboard.”
Dan Weseman, the man behind the Wicked Cleanex, The BTA 5th bearing, and the Panther project, the second winner of the Cherry Grove Trophy, is working his way toward a new goal is the land of Corvair powered flight. He is developing a made in the USA, true billet crank for Corvair flight engines. Follow this post and get an inside take on his motivation and the challenges involved.
Above, Dan in his new 12’x50′ climate controlled workshop built inside his hangar. He built the space to facilitate the development of and the eventual production of “Florida Panther” aircraft. In the photo are a fuselage side for the steel tube sub frame and an aluminum wing rib. Although the plane is intended to be an LSA legal, fun flying plane, Dan is building in enough strength for some advanced aerobatic work.
Dan Weseman has a well earned reputation in the world of flying Corvairs as a get it done kind of guy. Outside of aviation, people are impressed by people who get a lot done in a day. Inside aviation, accomplishments are done on a longer time scale. Building a plane has an element of “What can you get done in the next 4 hours?” to it that is very important. But it also has the requirement of stringing together a long series of these work sessions. Lasting accomplishments are built of this type of sustained efforts.
Dan often takes a modest tone on the outside, saying things like “we will see how this works” in discussing projects, but knowing him for many years, I have come to see that such comments are really to keep discussion low, and they address the fact that many new arrivals in experimental aviation are yet to see the sustained effort required to bring anything good to physical reality. Downplaying the discussion side of his efforts is a way that keeps Dan operating the project on his schedule, not on anyone elese’s expectation.
This has proven to work well in the long run. Dan, in joint effort with his father Jim, have now delivered more than 200 of their 5th bearings to Corvair builders. The bearing story is one of careful development and testing followed by steady customer support. Same goes for Dan’s efforts making “Cleanex” Corvair installation packages available to people building Sonex airframes. After building and flying his own aircraft and refining the installation, Dan moved to making the parts available. His installation components are compatible with all of our engine components. We even developed some parts, like the Reverse Gold Oil Filter Housing and the Universal #1 Exhaust specifically for Cleanex installations. The engine installation has been a steady success story. When I visited Dan’s shop there were 5 more Cleanex mounts in process being finished by master welder Vernon Stevenson.
Dan is now turning this approach to the subject of billet crankshafts. While other people have thought of this before, and Corvair race car guys have had a handful of them made by crank specialty shops over the years, they have not shown up in experimental aircraft. Here is where Dan’s unique background comes in. For a day job, he installs CNC machining equipment in industrial production shops in the southeastern U.S. His company deals with the transportation and installation, so he gets to work with all types and brands of machinery. He has been inside more machine shops than any other person I have ever met. He fully understands which type of modern equipment is best suited for making a run of billet cranks for high stress Corvair engines. Combine this with his background as a builder and a flyer, and the experience he has in bringing parts to the market and supporting them, and you have the makings of a success story.
A billet crank is made from a piece of round stock, typically in the case of the Corvair, a cylinder 6″ in diameter and two feet long. This material is most often 4340 alloy steel made under exacting conditions. This cylinder itself is a forged piece of material, not cast. Professional race car engine builders specify that these blanks be made in the U.S. with a paperwork trail that demonstrates their pedigree. Because 80% of the material in the blank is going to be removed to make the crank, it must be guaranteed to be homogeneous throughout the blank.
Hand making these cranks in a crankshaft shop is one of the reasons why they typically cost $3000. The material removal takes a long time on traditional equipment. Many crankshaft shops only have the reserve manpower to make a few of these a year. Dan is looking into a different approach, where he is going to have 98% of the material removed by very powerful CNC equipment, bar feeding lathes that can work from a 20 foot long billet. As a second step he wants to take them in groups to a crankshaft specific shop like Moldex, where those craftsmen will be able to put the finish grind and balance on the part. He is working toward driving down the price toward $2000-$2500 with a new gear installed.
Such a crankshaft can be made stronger than the original GM forged crank. Contrary to what many people think, billet cranks are not inherently stronger than forged ones. The grain of a forged crank actually makes it stronger than a billet in direct comparison. However, automotive cranks do not have large radiuses in the fillets. In cars they are not required. Purpose built aircraft cranks have much larger radiuses, reducing the potential for a stress riser. Billet cranks can be built with large radiuses, and this allows them to potentially withstand extreme forces better than a forged crank with smaller radiuses. At times, discussion on crankshafts is driven by people who don’t have a grasp on concepts like this. Productive understanding starts with a practical look at how the concepts are applied to our specific engine. Commentary without this isn’t worth serious consideration. People will always throw around statements like “they are 20% stronger.” No statement like that makes sense without addressing tension, torsion, bending or fatigue life. The real discussion is a far greater in depth, while focused on a far narrower scope.
A number of people think that the genesis of Dan’s billet crank project was when Mark Langford broke the back end of his KR-2s crank in November. In reality, Dan had long been planning on having a billet crank as an experiment in his new aircraft, the Panther. In his own style of letting the project set the timetable, not public discussion, he was working quietly on the topic, developing the plan as he worked in a number of different CNC shops that have the equipment that would make the project economically viable. After Mark’s comments, some builders started asking about billet cranks, including Chinese ones. In an effort to let people know that he was working on a U.S. made one, Dan mentioned this, and has a small email list of people who are following his progress. Mark Langford is one of the people who has said he will use one of Dan’s cranks in the next incarnation of his engine. To be clear, Dan’s interest in the development was driven by the fact that he is going to set up his personal Panther for some very hardcore aerobatics. He has told me he wants to use the Precision mechanical fuel injection we have for testing, and he is even considering an inverted oil system. In his 3,100cc Cleanex, Dan flew a tremendous amount of sportsman aerobatics on a stock GM crank. He did a lot of this without a 5th bearing. After he developed his bearing he retrofitted it on the same engine/crank and kept going. Over several hundred hours of hard flying he has not had a crank issue with either the nitrided crank by itself nor his 5th bearing. When it comes to flying like that, most people recognize that it makes sense to have a 5th bearing. Likewise, now that Dan is moving up a notch in the stress department, going to a large radius billet crank is just part of his plan to make sure that he has 200% of the strength he needs, not 99%.
The most common question that people have about these cranks is “Do I need one?” My primary answer for this is that the vast majority of builders do not need one of these. That is my opinion based on the big picture of statistical evidence we have from being at the center of the Corvair movement. I have seen Dan fly hard aerobatics at wide open throttle in his Cleanex for 30 minutes at a time on a stock GM crank. We have pilots like Andy Elliot who have flown hundreds of hours on a 3,100 without a 5th bearing. Mark Petz overhauled the engine in Bernard Pietenpol’s Last Original last summer. It had 800 hours and the crank was perfect, in spite of never having been nitrided and not having a 5th bearing. We have a lot of pilots with several hundred hours on non-nitrided cranks and no 5th bearings. It is all a matter of personal choice. Very seriously, I am not, and do not wish to be, in charge of anyone eles’s building, flying or life. The primary attraction to me of flying is freedom, and the root of this is being able to decide things for myself. I am not here to take that away from anyone. I take presenting the facts very seriously. I take countering disinformation seriously. I take the task of explaining the risks very seriously. I want builders to know the big picture. But I fundamentally trust that anyone who is rational enough to fly a plane can make the correct decision for themselves, given factual, accurate information presented without emotion. If I came out and said, you have to have a nitrided crank, a 5th bearing, or a billet crank, or I will not work with you, then I am dictating that our accumulated knowledge will only be shared with some people. I make strong recommendations, demonstrate that I believe in these recommendations by building engines that match them and flying behind them. But, in the final measure, builders are going to make their own decisions.
New people will often say, “Just tell me what to do” in homebuilding. This is ok when you’re getting started in homebuilding. Most of these people get off to a good start by replicating the engines that we build in our shop. Over time, this same person needs to transition to the mindset where they are analyzing the available information and making the decision for themselves. I want builders over time to understand the logic of all of the choices we make in our work. They are not required to agree with the choice, but it is not a sign of conformity if two people look at a set of facts and come to the same conclusion. Making choices for yourself is what being in command is all about. This is how you prepare for being aloft, especially with another person in your plane. It is the great reward of flying. Self reliance and earned self confidence also happen to be your best line of defense in any flying situation.
In modern life, people are less and less in charge of important decisions that count. On many fronts, society is trying to prevent you from hurting yourself, and the method they choose is most often taking away the ability to do so, not educating you and letting you choose the path. Flying, and homebuilding in particular, is the polar opposite of this. You have to have a really negative view of individuals to buy into a system that tries to prevent people from having the means to hurt themselves…The queen and the hive dictate to the worker bee his limited task, and when he has fulfilled it, he is no longer of any common good, and he is expected to die quietly because the hive programmed him to do so… In my book, humans are individuals, not insects. Any person who chooses do something simply because he wants to is affirming this. Any person who picks up a tool and sets out on a journey to create something of his choosing, a goal that does not serve the hive of society, can expect both the disdain of the hive and the warm welcome of other individuals.
I am going to run a series here called “Flying Planes.” We have an old section on our regular FlyCorvair.com Web site that covered the same topic, but it is out of date, and writing this series will bring it up to speed one story at a time.
With other types of aircraft, the plane itself is always the centerpiece of the story. With homebuilts, it is different. At the center of every homebuilding story is the builder himself. Looking at the plane can tell you a lot about the builder. You can get a good take on his workmanship, skills, taste in instrumentation, and creativity. Beyond these observable qualities, you can find out a lot more by getting to know a successful builder and asking why he chose a specific design, how he chose the Corvair, and how his previous experience plays into the aircraft he built. Besides being interesting, asking these questions and learning the answers is how new builders refine their own choices and make decisions on which path to proceed. Even if the answers you come to for your own project are not the same, they can still be honed by contrasting them with a successful builder.
Andy is an aviator of great experience, but his 601XL was his first venture into homebuilding. He holds a degree is aerospace engineering, a doctorate in engineering from MIT, and has several thousand hours of flight time, including a very long stint as a flight instructor in T-38 jets in the Air Force. He has taught as a professor at Embry Riddle Aeronautical University, and today is a full-time working engineer. You can comfortably say that the guy knows something about airplanes.
In our booth at Oshkosh 2011, I stand with three pilots who flew in their Corvair powered Zeniths. From left to right, Shane McDaniels who flew in a 2,700cc CH 650 from Missouri, Woody Harris in a 2,850cc CH 601B from California, and Andy Elliott in a 3,100cc CH 601B from Arizona.
I first met Andy at our 2002 Texas College. He was getting a good look at the Corvair, planning his next move in aviation. After our 601XL flew in 2004, Andy began thinking about the same aircraft, particularly a tailwheel plane like ours. Over time he chose a kit from Zenith and got to work on it. As he made progress, we spoke about Andy buying an engine from us. Our personal 601 had a 3100cc powerplant that I built to demonstrate some of the potential of the engine. It was assembled around a set of 140HP cylinder heads with their larger valves, and a very high compression ratio over 10.75 to 1. All of the systems on the aircraft are our standard Gold items, including the Front Starter System. The engine featured enlarged exhaust ports and very careful internal set up. On the dyno it exceeded 120hp, actually damaging the digital scale with the very strong power pulses from the high compression. Based on the internal changes and the displacement, I was fairly sure this was the most powerful non-turbo Corvair flying. We had it in the plane starting in the 2005 season, and racked up about 220 hours on it, including two trips to Oshkosh.
About the same time Andy needed an engine, another Corvair builder and friend of ours decided to make us an offer on our 601 airframe. A few phone calls and one Solomon like decision later, and our airframe was on a truck to Massachusetts, and we got the 3,100 ready to be shipped to Andy for installation on his 601 nearing completion. Before sending it, I pulled the engine down for inspection and out of general principle had the crank magnafluxed. It passed with flying colors, even though we had flown the aircraft very hard, and most importantly, it had not had a 5th bearing on it. The crank was just nitrided as was our standard practice in engine building. Although we could have sent the engine without the inspection, I thought it was well worth testing, because it had a fair amount of time on a very powerful engine. This was further confirmation to me that the nitriding was working. At the time, very few 3,100s had flow this amount of hours.
Andy likes to fly a lot, and once his plane was done he flew the test hours off in a very well thought out test program that reflected his professional background. We later had him document this and we printed it in our 2009 Flight Ops Manual. Over the months that followed, Andy built up time, a mixture of short flights in the southwest, and several trips to Oshkosh. In time he modified the airframe with small aerodynamic touches to increase its efficiency and control harmony. This included changing the elevator linkage and installing aileron spades. The engineers from Zenith were impressed enough with the aircraft to take the opportunity to fly it themselves at the west coast Zenith fly in.
Andy’s engine has made four separate trips to Oshkosh. Two under his ownership and two under ours. Pictured above in the 2005 Zenith booth Andy’s 3,100 makes its first Oshkosh appearance on the front of our aircraft.
The engine gave Andy steady service, which he credits to the certified MA3-SPA carb and an exclusive diet of 100LL fuel. (Other Corvairs can be set up for auto fuel, but the compression ratio of this engine makes auto fuel a non-option.) He was careful not to lean the engine at full power nor at low altitude, pointing out that the MA3 runs a very steady air fuel mixture under varying atmospheric conditions, so you don’t have to mess with the mixture if you don’t want to. Before heading to Oshkosh 2011, Andy had racked up 500+ hours on the engine (220 of these were under our ownership, 300 on Andy’s plane). I spoke to him about installing a Weseman 5th bearing on his aircraft, giving him the logic that if he was going to do it eventually, why not now? Although he had not built the engine himself and is not a mechanic, he found the installation straightforward with the tool kit and tech support provided by Jim and Rhonda Weseman. The installation was done over two weekends and the plane flew on to make an appearance at Oshkosh. It was selected to be the aircraft representing the Zodiac series at Aeroshell Square when the EAA presented the Aifetime Achievement Award to Chris Heintz.
Above, Andy’s aircraft at the EAA Chapter 1 Open House, Riverside, Calif.
Today Andy’s engine has more than 600 hours on it, 500 without a 5th bearing, 100+ with the Weseman bearing. He recently pulled the heads off and sent them to Mark Petz at FalconMachine.net for an upgrade to Mark’s specs. I originally had the heads done by SC Performance in California 10 years ago, and they were done to “state of the art” levels for Corvair auto racing guys. SC was a very well respected shop, but they didn’t use the types of seat alloys or valves that Falcon does. Mark inspected the heads carefully before reworking them, and was impressed at Andy’s careful operation; even with an extreme compression ratio the heads showed no signs of detonation. They were just losing compression through the old style exhaust seats. Andy ran the engine at high power settings, but Corvairs don’t have a real problem with this kind of work. Mark feels that considering Andy’s careful operation, the upgraded set of heads will go 1,500 hours. The bottom end of Andy’s engine showed no appreciable wear on the pistons or cylinders.
The upgrade to a 5th bearing and Falcon heads are not expensive modifications by aircraft standards. They each set Andy back about $1,000. You can ask any Rotax or Jabbaru owner if any upgrade on their engines costs this little. Combine this with an initial cost that was about 60% of either of the imports, and the engine still represents an excellent value.
In his travels Andy has met a lot of other builders at airshows, and people have written me privately many time to express how much they thought of the plane and the man. He has represented the Corvair movement in most of the western states, covering Copperstate, EAA chapter #1 Open House, the West Coast Zenith fly ins, and the Contact! alternative engine fly ins in Jean, NV. Additionally, Andy has used the aircraft to cover long trips to visit family and friends, including flights over the mountains in Colorado. He has a lot of praise for both the Zenith and the Corvair. What’s next for Andy? He is giving some serious thought to taking a step up in the speed and agility departments to a single seat Midget Mustang. The engine? The Corvair of course.
To read an updated on this story please click on this link:
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Every now and then the subject of having a new crank made comes up. With a little reasearch on the Net, people find out that new cranks have been made for Corvairs. These fall into two groups: Billet cranks made in the U.S. for Corvair race cars, and cranks made in China.
In this post, I am going to speak about the latter. First, let me say that a lot of people make comments or hold very stong opinions about things they have never seen. Most people are guilty of this in one way or another, and it’s mostly harmless. However, when the subject of airplane building is at hand, I always want to listen to a guy who has first hand knowledge, because in aviation, the results of poor information isn’t always harmless. When I speak on the same subject, I am very careful to make sure that the person reading or listening is getting an accurate picture, and that they also understand the parameters of the discussion. On the subject of Chinese crankshafts for Corvairs, I think that I have a particularly informed opinion, not because I understand the engine, but because I have also seen the Chinese cranks in person, I know the guy who had them made, was present when they were inspected, followed their issues, and I know the only guy who has flown one. Follow through this story with me and get an insider’s look at these cranks, and then decide for yourself how you would feel about flying behind one.
The story starts with Brady McCormick of Washington state, about 2006. Brady is a good guy, and a heck of a good craftsman, but he isn’t an engine guy nor has he ever had any kind of aviation training. He likes the Corvair for his own aircraft, a 701 he is slowly building from plans. He buys a lot of core engines, which all turn out to be early models which have short stroke cranks. Over several months he hatches a plan to have new cranks made. He starts looking around the U.S. and finds that billet cranks cost $2500 to $3000. He finds a Web directory run by the Chinese government to direct foreign buyers to Chinese manufacturers. By contacting an agent in Taiwan, Brady finds out that new forged cranks can be made for about $1000. Brady was going to use these to build engines and also resell them to builders. Quite a plan for a guy who had never built a running Corvair engine of any kind.
The catch on the plan came up quickly. The Taiwan agent stated that she needed $30,000 to have new forging dies made, before the cranks could be made on the mainland. To get started, she offered to have 5 cranks made from billets. These could be done without having dies because billets are just machined from round stock. Brady sent a sample crank, money for 5 billets, and a large deposit on making the forging dies. At this point he honestly thought that everything was going to work out, and that he was making a regular business arrangement, just as if he were dealing with a U.S. based company. Although I had not met him in person at that point, I regularly spoke to Brady on the phone, and as I listened to his great plan, I honestly thought his money was gone and he was never going to get anything. Something worse happened. They sent him the 5 billet cranks. Encouraged by this small first transaction, Brady borrowed $30K from his father’s retirement savings and sent it to pay for the forging dies. On that day he felt he had just made a move that would make his fledgling business “Magnificent Machine,” a major player in the experimental market. The long run would show something very different had taken place.
When Brady first announced his new cranks and put pictures on the Web, it started an Internet flap because they didn’t look like normal billet cranks, and Brady was prone to making statements about them that he couldn’t back up, like “they are 2.5 times stronger than GM cranks.” This was just stuff that he read on Web sites and wanted to believe. When he encountered people who actually had a university background in strength of materials, he was reluctant to admit he might be wrong. It was a rocky introduction.
I met Brady in person at the Arlington airshow shortly after. He was very different in person than what he projected on the Web. He was modest and much younger than I expected. In 30 minutes I decided I liked him and even though I am not a fan of things imported from China, I was moved by his desire above all else to return his father’s investment. I counseled him to change his Web site and online claims, and act more like his in-person self. I invited him to Corvair College #13 and he showed his stuff to our builders. At this show, Roy from RoysGarage.com was also a technical guest of mine. Roy took Brady aside quietly and showed him that the cranks were of marginal accuracy, and Brady should tell his source that the concentricity needed to be a lot better. Brady had two cranks that were 3.00″ stroke (instead if the stock 2.94″), Two that were 3.125″ and one that was 3.25.” To give you an idea of how much planning was missing, a 3.25″ stroke crank had the connecting rod actually hit the cam lobe on rotation. Brady had enthusiasm but not experience.
The first guy to buy a crank from Brady was Steve Makish, a friend of ours and a well known KR pilot of great experience. Steve understood that this crank was unproven, something of a test. He felt like he was a good guy for the job of test pilot. He bought a 3.00″ crank for his engine. After the short block was assembled at Dan Weseman’s with one of his bearings, Steve took it home to finish it. This is when he discovered that the rod throws on the crank were ground almost 1/8″ too wide. If assembled, it would have marginal oil pressure. Brady was informed, and he went out of his way to fix it; the best solution was having a custom made set of connecting rods. This took many weeks.
When the engine was assembled and run, Steve did his usual extensive ground run. After a long time, something didn’t seem right. Compression dropped off, and an inspection showed that the exhaust valves were bent. Usually the only thing that can do this is putting the cam in several teeth off, something a lifelong motorhead like Steve isn’t likely to do. After some time, it was noted that the keys on the back of the crank didn’t match the ones on the flange. A careful inspection revealed the following photos. The crank had been made undersize at the factory, and instead of scrapping it, they had made a hidden repair that had failed. Very luckily, this happened on the ground.
Above is the sleeve that was put on the crank. The stock crank has the same diameter as the outside of the sleeve. In this case, the Chinese had all the crank forces going through the thin section with threading on the inside.
The people who made this crank sold it to the broker in Taiwan who then sold it to Brady, He paid about $900 for it. I am pretty sure the shop in China that produced it had a tiny fraction of that amount of money in it. How cheap were they that they didn’t just trash this one and make another? They knew that this was going in a plane. They could read Brady’s Web site. They didn’t care, they were far away, and they were never going to get sued.
If you don’t know a lot about Chinese business ethics, you could easily dismiss this as a million to one chance of happening again. If you know a small sampling of their business culture, you will understand that this is a chronic problem in buying something from a country that doesn’t have the same ethics we do. I am not condemning the people of China, I am just pointing out that there is no rational reason to think that any businessman operating at Brady’s level can expect the kind of quality that is needed in aircraft parts.
Brady got Steve another crank and bought back all the other cranks that he had sold. He had a lot of money and time in his business, and he did listen to counsel about working his was out, but he had a gambler’s heart, and his approach was to double down on his bet. He borrowed more money and had another Chinese company make connecting rods. He ordered 500 piston blanks from a U.S. piston maker. He imported aluminum cylinders even though a number of people told him that these things would have long teething problems at best. All of this was done before Brady had built one single engine. I held a small College at his place, tried to get him to work on more modest things that would provide some cash flow. He listened while you were there, but he drifted back to his previous ways later. In the end, the Chinese kept all his money, he lost his business, his house, and a lot of the other things in his personal life unraveled. It was a long way from wanting to build a 701. It needs to be understood that he closed his doors after taking care of all of his customers. The only thing he kept was the one thing he was most concerned about losing, the thing that was probably never in jeopardy, his relationship with his father. His dad stuck with him all the way through.
One other issue has emerged with these Chinese cranks. Although they were always said to be made from billet, they don’t look anything like U.S. made billet cranks. Two people who know machining very well, particularly how cranks are made, both of whom saw Brady’s cranks in person, told me that they believe the cranks are cast steel. I listened to their reasons very carefully and I have come to agree that their argument makes a lot of sense. The Chinese are known for making millions of cranks from cast steel, it is an inexpensive process that yields a part that will work in an automotive application. The hidden defect tells me that anything is possible from China, and telling people that the cranks are billets when they are cast is not a moral problem for them. Today a Corvair car business in the southwestern U.S. advertises that they have these same cranks, and it refers to them as billets. The guy has no background in experimental aviation nor metallurgy, but he aggressively tries to steer aircraft people into buying them. No one should buy one of these for an aircraft. The Web site sells lots of untested parts, much of it sourced from the same people who made Brady’s cranks. There is one important difference between Brady and this guy: myself and the rest of the Corvair All Stars were doing what we could to get Brady to make better decisions and be more informed. He has willing to learn. The guy in the southwest has no such inclination, he just wants to make money off builders.
Although lawyers get blamed for a lot in U.S. aviation, I am going to make the case that you don’t get to see the good that they actually do. Putting emotion aside, think about this: Every year, countless people from outside of aviation refuse to sell products to, or work with, aircraft builders, citing the reason, “I don’t want to get sued.” Some of these people make good stuff that could be well used in experimental aviation. But a number of them make trash, or things that are not appropriate for planes, many of them have no idea of how aircraft work, and most of them have never even flown in a light plane. If those people make stuff for planes, and claim that their stuff is airworthy, they would get sued. The threat of legal action does keep good things out of the market, but it also keeps trash like the crank pictured above out also. That is unless the crank is made in China. You are never going to successfully sue anyone in China, their police state would never allow it. Their manufacturers don’t even have to consider it as a possibility. I am speaking from some level of being informed here. Friends of ours know that my brother-in-law is a partner in one of the world’s largest law firms. He is a global expert on international intellectual property, and has made countless trips to China since the early 1980s. He has said many times that you would never even get through the discovery phase of legal action against a Chinese company. The Chinese know this, and it means that they are more afraid of telling a production manager that they messed up a crank than they are of getting sued by the family of a guy who lived far away in a place they will never visit.
On an Internet Discussion Group, a well intentioned but misinformed homebuilder stated that he felt Corvairs should be built with new crankshafts and rods like other alternative engines. He further stated that he would not fly behind an engine built with used parts. Here’s a reality check: Virtually every person reading this who has flown in a certified general aviation aircraft in the United States has flown behind used crankshafts and rods, many of which have seen more than 10,000 hours of service. The overhaul practices, including magnaflux inspection, have long proven that people can safely take to the air with these components if they’ve been properly inspected and overhauled before assembly. The Corvair is no different. There are reasons why some builders might want a different crank for an extreme engine, but just feeling that any new crank is better than a reworked original one is an argument that seemed logical to Brady, a guy with no aviation experience. In reality, the Corvair has been flying for more than 50 years, and there is a known database of tens of thousands of hours on the GM crank.
If you look at automotive crankshafts, companies like Eagle and Scat have long histories of having cranks made in China. Tom Leib is the president of Scat. I have met him in person several times. A few years ago he wrote a long article in a manufacturing trade journal about the challenges of quality assurance in Chinese manufacturing. His thesis was that you’re going to get the lowest quality they can supply until you have your own people, who are ethnic Chinese, but paid for career long loyalty to you, on site where everything is done. Post process inspection in metallurgy didn’t count in his book. He felt that only major players would make it for this reason. The numbers he was speaking of to make this arrangement possible was 20,000 cranks per year. If you read the article, you will understand why Brady’s venture, or any plan to purchase from the Chinese that could be done by people in the small scale of Corvair flight engines, would end badly. I have good reason to say that Chinese crankshafts are not a good idea in Corvair aircraft engines. As we go forward, there will always be people who bring up the subject. If they do, ask yourself, what has changed since the factors that produced the defective crank above? I don’t see the nature of Chinese business changing, I don’t see a post manufacturing inspection that I would bet everything on, and the level of production will never allow on site inspection. For the Corvair movement, Chinese crankshafts are a dead end.
A lot of people thought my primary objection to Chinese cranks is that they were made in a communist country, where civil rights don’t exist. Other people thought that it was my bias for buying things made in America. I have said that I detest totalitarian governments, and that I make every effort not to support them economically. Yes, I have always tried to support American manufacturing and jobs for our countrymen, even before 1 out of 8 Americans was unemployed or doing work below their skill and dignity. But I can make a good case against using aircraft parts made in China to a guy who doesn’t particularly care about human rights or jobs. It is up to each individual to decide what is right for his own aircraft and the people who will fly with him while he is pilot in command.
Jeff Cochran, CH-750 builder from Alabama with a running 2,850 cc engine, writes:
Welcome back to the world wide web. You have been missed. Questions about the installation of your SS exhaust pipes. First, if ceramic coating of mild steel is bad, what about wraps on the SS system (except for the heat muff section)? Next, do the Heat Muff Box Ends need to be attached to the pipe and if so what is the best and worst method? And last, you say the pipes do not require tail pipe brackets, but the 601 Installation Manual calls for a steel tubing brace across the ends?
The new site is great, keep blogging.
Good to hear from you. The photo above is the first run of your engine at Corvair College #19.
Wrapping the pipes is bad for mild steel for the same reason why ceramic coating the outside of mild steel is bad: It keeps heat trapped in the steel, and mild steel can’t take this. If you look at the pictures of our Pietenpol in the late 90s at our http://www.flycorvair.com/carbice.html page, it had wrapped exhaust. I learned my lesson then. As a concept, it is worse than ceramic coating steel because when it cracks or disintegrates, you can’t see it. The only Corvair builder who I can think of who found this out the hard way was 601 builder and pilot Scott Laughlin. His wrapped mild steel exhaust gave in in about 100 hours, but he initially didn’t see it because it was wrapped. Wrapping the exhaust had its heyday in drag racing 25 years ago before coatings were available. Today they are a fashion statement on custom motorcycles. I can attest that it doesn’t work all that great either. My motorcycle, a Buell XB12X Ulysses came secondhand with a wrapped exhaust right where it passes my right thigh. It still radiates enough heat to be very uncomfortable. Sooner or later I am going to send the header pipes out to Jet Hott in Texas to have them ceramic coated inside and out. The best way to secure the heat muff ends it to get the box built and fitted right where you want it and then let a local welder put two tack welds on each end. The welds don’t have to be very big, two spots 1/4″ in diameter will do it. Other builders have used a hoseclamp above and below the box. Avoid anything that would puncture the main exhaust tube like a rivet or a screw. Your Zenith Installation Manual is an early one where we experimented with tying the ends of the pipes together aft of the nose gear. Subsequent experience has shown that this isn’t necessary.
This follow up came in from Gary Burdett, 750 builder from Illinois, also building up a 2,850 cc engine:
I take it that the short stubs are the place for the egt clamps.
If you’re planning on 6 egts, the stacks are the place to go. However, a majority of Zenith builders are using just 2 egts, one in each pipe, allowing them to monitor each side of the engine. In this case, they mount it about 6″ past the last stack.