Testing and Data Collection reference page

Builders;

I am collecting stories on testing we have done here. Virtually every month for the last 24 years has brought some type of testing or data collection on the Corvair flight engine. Some tests are fairly simple, such as building a new manifold and testing the output of a simple 1 barrel automotive carb, others like building and dyno testing EFI systems were more complex. This goes on continuously. Many of the tests go undocumented, or show themselves to be fruitless or economically unusable. Many test only provide a puzzle piece that is useful on another project years later.

Most alternative engine outfits are only interested in selling stuff, and more often than not, they did almost no testing before going to market. Many companies start selling engine before the first example has flown 100 hours, and I can think of a number of now defunct companies that sold engines long before even a single example had left the ground. The common element with all of them was viewing testing as just some useless overhead that cuts into quick profit margins. We are just the opposite. Remember that teaching builders about their engine is our primary goal. A a learning focused company, reasearch, testing and evaluation has provided the very material our program is made of.

Below are links to several stories that give a glimpse of the practical testing that has always been integrated into my work with the Corvair. Just stop and think about how many time you have read in a magazine article or sales brochure that the horse power output was from “Dynamometer tests”, yet, how many times have you ever seen a picture of any of these engines actually on a dyno? Personally I have seen at least 200 claims of HP output alleged to be measured on a dyno, yet I have only seen pictures of 4 different engines on an actual dyno run. In an era were virtual everyone has a cell phone, and every one of them is a camera, why do you think that 196 companies didn’t end up with a photo of their engine? Just maybe, the only “dyno” run they did was an imaginary one for the brochure.

I have said it before, If your goal is to Buy something, any salesman will do. If you goal is to learn, build and fly, to be the master of what you are doing, they you need someone you can learn from. I am willing to share what we have learned in many years of reasearch and testing with anyone who came to experimental aviation to learn and build.

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Above, the EFI 2,700cc Corvair in 2007, at power on my dyno. The urethane wheel directly reads foot pounds of torque off the digital scale.

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Click on any title below to read the full story of that test.

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Dynamometer testing the Corvair and O-200

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Dyno testing Corvairs, 2008

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Turbocharging Corvair flight engines, Pt #1

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Turbocharging Corvair Flight engines Pt. #2

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Torque, HP and Thrust tests

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Thrust testing 85 and 100 hp engines

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Testing Turbo Corvair and Rotax 912S.

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Panther Engine propeller test

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Ignition system, experimental “E/E-T”

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In Search Of … The Economical Carburetor

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Great moments in aircraft testing -2003-2004-2008

Builders:

In two weeks we will be headed back to Oshkosh. Once there we will be surrounded by hundreds of companies that will all attest on a stack of Bibles that they have carefully tested all of their products to protect the safety of their customers. In with these people will be at least 30 companies selling engines. Every single one of these companies will tell you without blinking an eye that their engine power output numbers are the result of careful Dynomometer testing. Almost all (90%) of these companies are lying about this.

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Traditional dyno testing is expensive, and a bit of a production to adapt an aircraft engine to. To learn much, it requires hours of evaluation, and runs at different conditions. Any company that does this would be justified in taking a photo of this milestone in their company history…….except you can politely ask to see a photo of their engine on a dyno, and of course they will not be able to produce a single image of their engine running on a dyno. I actually had one company tell they had done 100 hours of testing, but had forgotten to take a single photo of it. In an era where nearly every human has a cell phone that is also a camera, please tell me who would believe this?

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There are many kinds of dynos. Basically they all apply a load to the engine, and then measure the equal and opposite torque reaction resisting this load. No Dyno measures HP; they measure torque. HP is a calculation based on torque and RPM. If you building a plane, you don’t need to know this, but ideally everyone selling engines would, (but they don’t). A real motor head, like yours truly, knows this stuff. Combine this with some basic fabrication, and “Taa Daa!” the $500 dyno. Our dyno used the prop to generate the load,  allowed the engine to rotate on it’s crank axis by using a front spindle from a Corvair car, and measure the torque with a hydraulic cylinder. Later we simplified it further with an electronic scale for measurement. Using a digital optical tach, the accuracy measuring HP was within 2%

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I didn’t invent this kind of dyno, it has been around a long time, pictures of them in 1960s Sport Aviation magazines. This isn’t even the simplest kind of dyno. In one old Sport Aviation there is a picture of a Corvair  hanging on a steel cable turning a prop, with a wooden arm touching a scale. Yes that works also. The pictures of our set up have been on our webpage for more than 10 years. It would be very easy for any company selling engines at Oshkosh to have built their own version. Easy, but not as easy as telling people they have hundred of hours of testing, but forgot to take any photos.

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2003- Above, Oil system testing at Spruce Creek airport, 2003. We were testing how much pressure loss the cooler had when the oil in it was cold soaked for an hour at 32F. Testing like this is serious business. Note that Gus Warren liked Becks Dark, and I liked Michelob. Lot’s of companies like to have the appearance that they test products: they put people in lab coats and have them make scientific faces.  I don’t care for appearances, I just want results, and the picture shows we drank beer while we let the oil cool off. I can put on a lab coat a lot faster than a salesman can become a motor head and teach builders anything valuable.

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2004- Above, an O-200 on our dynamomemter; test crew from left to right, above: Gus Warren, Detroit Institute of Aeronautics, A&P 1990; Steve Upson, Northrop University, A&P 1976; yours truly, William Wynne, Embry-Riddle Aeronautical University, A&P 1991. While the way we dress may be slow to catch on in high fashion circles, we certainly know our stuff about all types of aircraft powerplants.

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2008- Above, Kevin and I are standing on my front yard, wearing jackets. We were waiting just before sunset for a rare weather phenomena to occur: a perfect standard day of 59F 50% relative humidity and a pressure of 29.92. Any time you read a dyno report and it says “corrected horsepower,” they’re making a calculation, sometimes accurate and sometimes not, to adjust for their test conditions not being at standard atmosphere. Because we live in Florida near sea level, there was actually  three occasions in four years when these conditions were met on testing days, and all our results we calibrated against these standards.

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How you can build a Dyno for $500 if you know how they work and you can weld:

Dynamometer testing the Corvair and O-200

A page devoted to all kinds of testing:

Testing and Data Collection reference page

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Air / Fuel ratios on Corvair carbs.

Builders,

Here are some short notes on the topic of carbs.  It is my hope that builders will read and think about them, consider the logic before jumping up to debate. The Comments are based on 25 years as a working aircraft mechanic and working with Corvairs since 1989. These comments are not based on a single planes experience, but take into account all types of testing, education, and practical experience.

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How Rich is right?  Recently, a builder has told people that correctly running aircraft carbs on Corvairs need to have black sooty tail pipes.  I can flatly state that this is way too rich, and there are a number of very good reasons why you should not fly a carb running that rich.

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As a logical base line for what exhausts should look like, perhaps we can all agree that an Exhaust of Certified plane, running 100LL fuel, with a correctly running engine, with by the book performance, a Certified aircraft carb running without adjustment for more than 20 years. is a standard we should use. This engine has never fouled a plug in 17 years, has never harmed the engine in any way. Notice that the inside of the exhaust pipe has a dusty light gray color, and that new paper towel was vigorously wiped on the inside of the pipe, and only produced that light stain between my thumb and the exhaust pipe. This is the correct color and soot content for any Corvair running an aircraft carb.  I know this from working with countless flying Corvair powered planes over the years.

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Why not black and sooty? A correctly running aircraft carb on an air cooled engine will have an air/fuel ratio of about 12:1 in normal cruise. This will automatically go richer, to some thing like 10.5:1 at wide open throttle, and in low power cruise at altitude, it can be leaned to 14:1 for maximum efficiency.  Any engine that is making black soot in the exhaust and can be seen to visibly smoke at 1,000 rpm is running an air/fuel ratio of 9:1 or so. I know this not just from books, and working on certified planes, but from directly reading a laboratory grade A/F meter while running an EFI Corvair on my dyno in 2007:

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Above, An exhaust evaluation as part of an Electronic Fuel injection test on a 2,700cc Corvair in 2007. It is shown running at power on my dyno. With this arrangement, a simple twist of a knob on the computer produced any A/F ratio you wanted to test. This is how I can say what A/F ratio produces visible smoke on a Corvair, and it is part of how I can speak about it’s relationship with power output.

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At any airport with a density altitude less than 3,000 feet, your Corvair should run perfectly smoothly and make good power with the mixture set full rich, just like any Cessna 150 with the same carb will do.  One of the reasons why I use MA3-SPA carbs is so they have the exact same ‘normal’ operation as any certified plane I have flown, and if the carb doesn’t work like it does on a Cessna or a piper, don’t fly it, period.

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A builder with an MA3-SPA carb reciently said his engine only ran correctly with the mixture pulled half way out. He was considering actually doing his first flight in that condition. His home airport elevation is only 516 feet. If I went to his airport, and got in a Cessna 150 and it took pulling the mixture out half way to run correctly, You could only make me fly that plane with a gun to my head. Something is wrong with it, and sane people do not fly planes with things wrong with them. It doesn’t suddenly become “O.K.” because the carb is now on an experimental. Wrong is wrong, time to correct the issue, not to find some condition where it kind of works for the first flight.

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Any guy who would consider flying a plane in that condition, has missed the point of this story: Risk Management, Judgement Error, money in the wrong place. Where Ken Lien was killed on the very first flight of his plane because he didn’t bother to correctly assemble the mixture control on his plane and it moved to idle cut off on its own. If you are in a plane, getting ready for the first flight, and the mixture has to be pulled half way out to run, please explain to me how you know that this isn’t the first sign that the mixture is assembled incorrectly.  You wouldn’t, and there is a significant chance the engine will quit.  People who want to die should step in front of busses, not fly planes that are not set correctly, as using a plane and poor judgment to end ones life only unfairly punishes those of us who practice intelligent flying.

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If the mixture was half way out on the first flight, and the new pilot had to do a go around on the first approach, most pilots would instinctively push the throttle, carb heat and mixture to the firewall.  This works, and it is the correct procedure. However if the pilot is tolerating a plane that must have the mixture half way out, when he does this, the engine will quit, he will overshoot the runway, and smash up the plane on the over run. All the local experts will then say “The Corvair quit, I told him not to use a car engine, he should have used an O-200” Neatly ignoring the fact that it is the same carb as the O-200, and it would have done the exact same thing.  If instead, the same pilot stepped in front of a bus, preferably while holding the hand of the ‘Expert’ who tells everyone not to use car engines, aviation would benefit, and the rest of us would come out ahead. Cold, but you know it is true.

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Engines running black soot are wasting fuel, prone to fowling plugs, can damage the cylinder walls, and will have excessive carbon build up. On the other hand……..wait, there is no upside.

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Anyone who says that an MA3-SPA needs to be jetted differently for different displacement Corvair engines is wrong. Think of how many different engines have run on my test stand, all with the same, untouched in 15 years, MA3-SPA. Note that I have the mixture set full rich on the stand, and it runs cleanly on all engines. And yes, my stand has both EGT and O2 sensors. Beyond this, Dan Weseman and I recently took his 3,000 cc and 3,300 cc Corvairs to one of Florida’s most respected dyno shops and ran them both is a day long session.  What carb did we use? Why the same one off my run stand. It ran perfectly on both motors and the shops very elaborate instrumentation showed that the air/fuel ratio stayed correct through out the power range on both engines, without any kind of adjustment. Aircraft carbs work like that.

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Would you like to know how aircraft carbs are supposed to be operated? Read this story: Cylinder Head Temperature measurement and learn what a Lycoming Operations Manual is.  Down load it, print it, read it and know it. This is what successful people will do.

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Conversely, You could get advice from a guy who is neither an pilot nor an A&P, who has never owned nor flown a plane with a mixture control, teamed up with a guy who has never seen a Corvair turn a prop in person, and another guy who damaged his engine by using a carb no one ever head of so he could save some bucks. Take your pick, but if someone doesn’t like the concept of listening to the professionals and people with experience, again, I am going to suggest that bus thing again, I know it sounds mean spirited, but people willfully doing dumb things shouldn’t even be called ‘accidents’ because they are not really. an accident is someone trying to do the right thing. Willfully choosing not to do the right thing is not an accident.

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This ends the technical part of this story.  No valid technical information follows.

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I am not listening to William Wynne because:

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One: He sounds arrogant, and although I have never met him, and he wrote stories about people he loved: Risk Management reference page in hopes that others could avoid being hurt, I still say he is a jerk because I found two sentences in the 855 stories that are on this site that offended me, and I refuse to learn anything from him since.

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Two: I own a Prius, and he is always mocking people who own Priuses, and I can tell he isn’t kidding, and he feels superior about this, which is stupid because as a Prius owner I alone have a right to feel superior to all other car owners because I know the best way to protest the use of fossil fuels is to buy a car that you can feel superior about.

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Three: When I was in his tent at Oshkosh pontificating about how America has been ruined because no one follows the Ten Commandments anymore, he asked me to name them, and I couldn’t. The year before I said the problem with America was no one followed the Constitution, and he asked me how many articles it had and I said 10, and he said “guess again, you are off by three” , and I guessed 13.  I don’t get the connection that I should read more before being sure I am right.  I never listen to people with long hair, even though William has essentially the haircut as Jesus and everyone at the Constitutional Convention of 1787.

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Four: I don’t listen to people who sell things, because they are trying to make money off me. I only listen to people on the net who’s opinion about how to do things can’t get them a job doing it, nor is it apparently worth money to anyone. Those are the people I trust.  Yes, I know that I should trust William because he has a vested interest in my success even if he actually likes me or not, But I would rather trust people I have never met, who write in nicer tones, who I have a simplistic childish belief are motivated to tell me the truth, unstained by their limited experience, personal bias, and ego.

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If anyone read the above for points and didn’t find them funny, you probably have good taste, and I remind you I am a mechanic, not a comedian. I have a small but consistent group of people, most who have never met me, who remain quite sure that I have a “Condescending tone” and a “Giant ego”.  Before anyone is temped to say those things, I ask that they read the two paragraphs below, which appear both on my website and in every manual we print, and please share with me how this isn’t adequately honest and frank:

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“If you have never met me, but read this and think that I am charmed with myself, you got it all wrong. I know countless humans who are better people than I. They are kinder, smarter, and harder working. I can’t sing nor dance, I learn slowly, and I can’t stand to hear my recorded voice nor see my image on film. If I was once handsome, all trace of it is gone along with my uncorrected eyesight. I can be a conversational bore, and I deeply wish I had given my parents more moments to be proud of me. At 50 I look back on my life with a very critical eye and stand on the far side of a very wide gulf from the heroes of my youth. Even our dog, impeccably honest and loyal as canines are, Loves Grace and only tolerates me.

Honest evaluation leads to harsh thoughts like this. I spend a lot of time alone and have long bouts of insomnia, which can lead to thinking about things excessively. But the secret I would like to share with anyone who at times feels the same way, is that I have a sanctuary where I am insulated from much of my self-criticism, and a have a front, where at 50, I am much better on than I thought possible in my youth. When I am building things with my hands in my shop, I rarely feel poor. Although I now need glasses to do any close work, and my hands have lost a lot of dexterity, I am a far better craftsman than I ever was in my youth. I am not a great craftsman, but over a very long time I have worked to develop these elements in my life, and I compete with no one except who I was last year. While all else fades, these things flourish. It is a gift I am most thankful for.”

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YOU MUST SET THE TIMING ON YOUR ENGINE

Builders,

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This is not a story about people making mistakes, because everyone does that when they are learning, This is a story about people reading the correct way to do things, and then thinking it over, and deciding not to, because they have some rationalization like ” I think someone did that for me” or “I’m busy, I will look at that later” or “I read that once, I suspect that mine is wrong, but there is too much information on ww’s site, it can’t all be important.” I wrote this last night after working 18 hours in the shop. It has a lot of spelling errors, and we have just 24 hours before the college. I was going to take 10 minutes to correct the spelling, but thought about the guy who will later say “I didn’t set the timing because I decided the advice wasn’t any good because I am a grammar and spelling Nazi and I can’t get past that, even to learn how to save my life.” Have a nice day.

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Above is Gardiner Mason’s Pietenpol. The plane was nearly destroyed in the sun n fun tornado, but he rebuilt it. It flew for years and had a condition inspection every year. It was wrecked in a hard landing that tore a wheel off, it had a number of forced landings. During the years that Gardiner flew the plane, he adamantly refused to ever set the timing with a light, he never did it. He no longer flies a Corvair, and I am glad about that. Let some other engine be blamed for his death. BTW, Gardiner flew for both the military and Delta, and has 30,000 hours, and I honestly have to say he never learned anything from me, in spite of many attempts on my part: http://www.flycorvair.com/pietengineissue.html today his engine runs perfectly in the hands of someone willing to use a timing light: Terry Hand’s 2700 cc Pietenpol engine – w/Weseman 5th bearing

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I have said in countless places that every one must check the timing on their engine with a timing light before flying it. I have even said that I suspect more that 1/5 of the people who fly Corvairs never do this. Perhaps you have read this and thought I was bull shitting people….Well understand this, and read it clearly, Today, I had two people with flying planes tell me in a single day that they never checked the timing on their engines. Yes, two in one day.

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Guy “A” wrote with a picture that showed a broken piston ring, and asked what caused this? When asked, he stated that he had never checked the timing, because he had bought the engine from us years ago, and just assumed that it was OK to fly it without ever checking the timing.

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Guy “B” wrote to say that his plane has one flight on it that went OK. When asked, he stated that the Cowl inlets were only 3.6″, He had no EGT information, one CHT, and he never set the timing on the engine. Again he bout the engine years ago, and some how assumed that it would be fine.

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Here is what is wrong with that mentality: I have said in countless places, that being an aviator is about leaving nothing to chance that you can easily check yourself. Since you have to own a timing light, and you have to check the timing at least every annual, why wouldn’t you check it before flying. “Because I thought someone did this for me” is not an acceptable answer in aviation if you are planning on living long.   If I sold you a gun several years ago, and then you left it in your barn for several years, would you pick it up and handle it without checking to see if it was loaded? Only if you were a fool. Likewise, during an engine installation, there are many ways with lifting the engine, installing baffling, wiring the ignition, that the timing could be altered. It takes only ten minutes to check……but still, people who took 5 years to build a plane, evidently don’t have that 10 minutes. I wouldn’t install a Lycoming engine in a plane and not check the mag timing. Why is this OK to do with a Corvair?

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I have to ask myself why I bother to write detailed stories and organize the in this format: Engine Operations reference page if people are not going to read them. In a previous photo Guy “B” sent me a picture of his engine running on his plane, with no cowling or airbox. I have said countless times that this is totally unacceptable, the same as running a water cooled car without a radiator or coolant. Yet there was some need to do this on a brand new engine. If there was ever a time in the life of an engine not to do this, it is when it is brand new. Between this, the undersized inlets, no timing set, and no egt information, how much damage do you think was done to the engine? If the engine fails in a few hours like Guy “A”‘s engine did, please tell me if you thing that all the guys in their EAA chaperts are going to say “I can’t believe he didn’t bother to take 10 minutes to set the timing” or do you think they will say “Stupid Corvairs, what a rip off that long haired jack ass in Florida is.”

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How many people are going to try this? I don’t know, but here is a story about a guy refused to buy a timing light and check the timing on his Corvair, because I had build the engine 10 years earlier, and it had been sold twice since then, moved all around the country, and put on two different planes, but he was still sure that the timing must be set correctly, because I built it a decade before. Guess what happened? He crashed the plane on the first flight, with a passenger. Understanding Flying Corvairs Pt. #6, 98% DNA not enough.

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In 24 hours we are leaving for Corvair College Number Thirty-Five. Is anyone learning anything, or am I just assisting in a free assembly service? This website has 740 stories on it, including many specifically on the need to set the timing on every Corvair. Is anyone reading stories like Ignition Timing on Corvairs or When to check your timing, Lessons learned Pt#2 which contains the sentence : 1) The timing needed to have been set on installation and checked at least at each annual. Please show me where it says “unless you think someone set it for you years earlier”

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Every week brings this kind of news. Last week I spoke with a guy who has been flying his plane for four years…..and he has never done a compression test. Try this, call your FSDO, tell them you don’t believe in compression tests at annual condition inspections and see how fast they revoke your repairman’s certificate your plane. Better yet, tell ask your insurance agent if your coverage is still valid if you only do part of a yearly inspection. Freedom to build homebuilts doesn’t mean that one is free from following standard procedures of aviation.

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The thing that gets me the most is the guys who are the beneficiaries of some great research and writing I have done, but willingly choose not to use the information, because they don’t have the time to correct some stuff, but evidently they have plenty of time to rebuild their plane. .Example: Plane flying to Oshkosh, with the landing gear 9″ too far back. I inspected the plane in California, told them the plane had poor CG and incorrect gear location. Neither corrected. On the way to Oshkosh, the engine is running poorly, (problem later traced to certified carb) but they flew past several optional airports to get to the one where the support van was…and promptly put the plane on it’s back…and said nothing when internet people blamed the accident on the Corvair engine of course. Plane flying again now, but with Chinese rockers…..

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Plane under construction for 20 years, finished the engine at a Corvair College. Made a custom and unique cowl, but never felt the need for a CHT to see if it worked, operating at 7,000′ DA, leaning the carb, but of course no EGT, inspite of the fact I have said in countless places a Corvair leaned to rough running is detonating. Main gear installed 7″ too far aft, in spite of my reports on CG….First flight last 20 seconds to loss of power.. with gear too far aft plane ends up on it’s back….It is publicly blamed on my ignition buy builders “Expert”…plane is flipped over, and proves to run perfectly on points, pilot quiets admits he never flipped the switch to the back up…Later testing shows that distributor runs perfectly on BOTH ignitions, the problem was caused by the experts wiring.

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Want to know how many Corvairs have been wrecked by running out of gas? Read this: Comments on aircraft accidents, everyone on the net thought that the accident that sparked the debate was caused by the Corvair…Maybe, just maybe I already knew that the pilot was a danger….He had damaged his $35 cam gear by not reading the installation instructions, so he didn’t replace it, he chucked it in a lathe and turned the aluminum gear down to save the money….and later tried flying his plane with only 5 plugs screwed into it.

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Think that was the only time a pilot flew on five cylinders? Guess again, We had a pilot who did his first several flights, but missed that he never connected the 6th plug wire….He was also doing the flights with no working charging system. Same guy later flies his plane a 601, with 4″ of lateral slop in the stick from completely slacked aileron cables. Why? because he “just had to get to his destination.”.

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How about flying to Oshkosh, having 80 hours on the plane, and never having changed to berak in oil? How about the same thing with 65 hours? How often do you think those builders inspected under the cowl? What did they learn?

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I could keep typing these stories for hours.  Right now, there is someone working on making my list of stupid stories one longer…Just make sure it isn’t you.

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“Beautiful” Garbage from a bankrupt source

Builders:

At Corvair College #31, one of the builders on hand brought an engine he had waited 5 years for.  He had originally ordered it in 2009 from a Washington state outfit named “Magnificent Machine LLC”. They have long been bankrupt, but the former owner tried to make ‘good’ on a $10,000 paid order. When the engine came to the college, I got a good look at it, and even called the builder, to ask questions about it.  To cut to the chase, the engine is junk, it might have $1,000 in useable parts in it. It was a long time to wait and a lot to spend on trash.

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Above, a simple shot of the head of the engine in question. Can you instantly spot the issue? Yes, the motor has junk lock nuts on the valve train and no exhaust rotators, but that isn’t the big one. Look at the top of the push rod tubes: see how the flat guide plate is crushing the top of the push rod tube? This head actually had over 1/8″ milled out of the head gasket area, so much that the pushrod tubes no longer fit, and the rocker arm geometry is a mile off. This will destroy the guides in short order; the compression ratio on this engine is far too high; it can’t even have simple future maintenance such as a heli-coil put in a spark plug hole ever. I spotted this because the engine only had 6 fins on the head instead of 7.  The heads were junk anyway because the intake logs were milled off for a dubious special intake that ‘looked cool’ but had no actual testing or logic. The builder told me the engine was run for a few minutes, but confessed it was plagued with oil leaks. He didn’t see that they were from the push rod tube O-rings no longer contacting the correct part of the head.

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The engine had many other issues. The cylinders were not bored on a boring bar, they were clamped in a lathe, and cut with a fixed tool. No rational person would do that. The crank was nitrided at a shop with no magnflux equipment. It had no harmonic balancer; it had a starter on the back of the engine which loads the rear of the crank. And that is just what I could see looking at the outside and under one valve cover for 4 minutes.

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The builder’s name is Brady McCormick. I do not critique the man without knowing him. I held a Jr College at his shop in Paulsbo WA in 2009. I was friendly with him and had him at CC#13. I have stayed at his house before. Brady had ambitions of being a major player in Corvairs, but he actually didn’t know much about planes nor automotive engines. He had never built a plane, had never had a single hour of A&P training, was not a pilot, had no significant flight experience, had never soloed a plane, had a weak high school understanding of physics and chemistry, and he had never rebuilt engines nor been employed in the automotive world.  He actually didn’t understand the extent of things he didn’t understand.

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After the Jr. College I met with Brady and his father. Brady was close to broke, and they appeared to be open to ideas. I and counseled him to stop trying to ‘develop’ new ideas, such as their own 5th bearing  and just work toward becoming a west coast build center that worked with proven ideas. I pointed out that I had my own flight proven 5th bearing design, yet I build motors with Weseman bearings. Brady listened with folded arms and said he could design better things than anyone, this in spite of the fact my visit had revealed he had not yet built one single running engine. His wager on this turned out to be his company, his house, marriage and his fathers savings. He lost.

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Below is a picture of the final phase of Brady’s attempt to be recognized in Corvairs, and to prove that my values of education, testing, quality control and simplicity were antiquated and stupid. One of the elements of this phase is his attempt to bring Chinese cranks to the market, with no testing. To read how the very first one failed, read this link: Chinese Crankshafts

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CH 601 XL B with Corvair

Above is a 2011 photo from the Zenith Builders site. It is an engine that Brady built for a guy, (it was not Brady’s plane, he didn’t have one.) Many people were impressed, thought of this as something great. It never flew nor ran. Bray was a good welder and a fair machinist, and could make things that looked good to amateurs. Problem is that planes need to be good not look good.  To people who don’t know better, this is impressive. If you understand modern EFI, this is wired like a Christmas train set, has no redundant ignition, and no design in airflow. More practically, this engine has no harmonic balancer, no cooling baffles, no Safety Shaft, and the big one, no 5th bearing.

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Below are a sample of the comments from other Zenith builders that the above photo brought out on the Zenith site. This is a good lesson: Many new builders without appreciable experience in aviation think that they can read websites and make valid evaluations of products, like they were reading a copy of consumer reports. I am sorry if this offends, but it doesn’t work that way in aviation. It is a highly technical subject, and the same way that Brady didn’t have the experience to make the stuff, the people below didn’t have a clue about that they were complementing. When I collected the comments, I took a few minutes to look at the pages of each of the commenters. None of them ever finished their plane. Want to avoid ending up in the same boat? Focus your time, attention and funds on proven products from people who value education, testing and quality control. -ww.

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If you would like to learn more about how fuel injection is actually done, and see it on running Corvair flight engines, read this: Fuel Injection – Corvair flight engines reference page

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Comment by Greg Walsh on February 15, 2011 at 4:05pm

Beautiful looking installation.  What is the total engine (FF) weight??

Comment by Andre Levesque on January 28, 2011 at 2:44pm

Hi Brady !I have been on your site many times. Beatiful work…. Just didn’t realize it was you -:)Now I understand the cleanness of your install….you’re a PRO.So nice to see craftmanship.  It Keeps us inspired  -:) and standards to adhere to….LOL

Comment by Brady McCormick on January 27, 2011 at 11:26am

Thanks 🙂 I Like to keep things clean. :)Steven: you can check out my website for more info if you like? www.magnificentmachine.comI build parts & engines. 🙂 

Comment by Jesse Hartman on January 27, 2011 at 10:39am

That is seeeeexxxxyyyyyyy

Comment by STEVEN and TARA SMITH on January 26, 2011 at 8:10pm

Hi Brady. I have been trying to find how to build a corvair with a rear flywheel like yours. please send me in the right direction. Your airplane is gorgeous.

Questions from potential builders:

Builders,

Here are some questions that came in as comments on other stories:

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Frank Stephenson writes:

“While there will be many different results, I am wondering what the average time before overhaul may be. Also what are we looking at cost wise for one of these engines and the average cost of an engine mount? I am considering selling my current conventional geared C-172 with a C-O300B engine and buying or building something a bit smaller and more efficient. I really don’t know anything about Corvair engines other than I know of several folks who have utilized them, but I don’t really know anything about their results. I have found, in general, that automotive engines don’t make really good aircraft engines, but some VW engines I have known of are an exception and apparently the Corvair engines may be an exception.”

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Frank, the minimum time between overhauls on a well built engine is 1,500 hours. Ten years ago we listed 1,000 hours as a very conservative figure, since then, improvements like using valve rotators have driven the life span up significantly. The Overhaul cost on the engine is very low, on the order of $2,000 to replace almost all moving parts or recondition them. You can lean more at this link: Basic Corvair information I understand that many automotive engine engines have a poor record, but I have been doing this for 25 years, and we have earned an excellent one. You can read this link: Planes flying on Corvair Power, and see many examples. For the cost of motor mounts, just look at out catalog,http://www.flycorvair.com/, and page down to Group 4200, it lists the price of every mount we make.

I know VW engines have worked for many people, but I will put the track record for reliability, power and TBO of our work with Corvairs against any VW based engine. There is a lot of information on our main webpage, http://www.flycorvair.com/. I understand that it looks overwhelming, but better too much than to little.

Here is an important point: I don’t think efficiency is a good enough reason to move to homebuilding. Lets say your Cessna does 110mph on 8 gallons an hour. There are several Corvair powered planes that can do that on 5 gallons an hour, even some on 3 gallons an hour. But even if you were to cut your fuel costs on flying 200 hours a year from $8,000 to $4,000 per year, I don’t think it is enough motivation to send a guy to the shop for 1,500 building hours. The only people that consistently succeed at homebuilding are the people who inherently would rather fly something the personally built, and people motivate by the desire to learn new skills. I have met very few people motivated just to fly less expensively who thought in the long run that homebuilding was worth it. Consider this carefully, you may have a better time staying airborne in the plane you have.

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Steve Spears

“Sir, I am currently building a RW26 Special ll and I would like to use the Corvair engine. However, some people are telling me that it is to heavy for the aircraft. What are your thoughts and do you know of anyone who has used a Corvair engine in the Rag Wing aircraft? I read what you wrote about the Pietenpol and am encouraged that I can use the engine”

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Steve, I looked at this pretty closely for an hour the other night. I tend to think that a Corvair is too big to the R-26. The 912 appears to be as large an engine as people use. Several of Rodger Mann’s designs have flown with Corvairs, but I wouldn’t call any of them an ideal match. I am guessing that a Rotax 503 is really the optimum engine for many of his designs. For a comparison of how heavy duty a Pietenpol is built, the longerons in the fuselage are one inch square spruce from the firewall to the tail post. I am pretty sure the R-26 is lighter than that.

For any plane that you are wondering about Corvair power for, the best rule of thumb is asking if the same plane has flown with a Continental o-200. If it has, a Corvair will always work in it. For a comparison of the two engines look at this link:Corvair vs O-200….weight comparison and this one:Dynamometer testing the Corvair and O-200. We also have a lot of info on comparisons to 912s at this link: Testing and Data Collection reference page.  -ww.

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Myths about propeller efficency

Builders,

On the Pietenpol discussion group, a well meaning guy reposted a story from the 1996 Pietenpol newsletter. The subject was on prop efficiency. It included the comment:

The Corvair engine is another compromise. They have a loss of efficiency due to the small diameter propeller and accelerate poorly (due to the tall gear effect) but produces good power. ” 

The guy who posted this probably didn’t know it, but I know that the comment is without merit, and no one who actually conducted a test, or understood propellers would make such a comment. Yet, here we are, 18 years later, in the information age, following the same myths that have been floating around for decades.

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The above comment has no educational value. Take it line by line: All engines, not just a Corvair are a compromise, period. Testing shows that a 100HP engine climbing at 60 mph with a 66″ prop may be close to 95% as efficient as one with a 72″ prop; Ask any tester you like, there is no such thing as an engine that produces good power but accelerates poorly. This only happens when it has a bad prop on it.

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OK, the whole point of having a dialog, reading thoughts or communicating about the building of planes is to learn something and use this knowledge to improve the plane you are building. The comment above serves none of these functions. It is only valuable to people who which to reinforce false realities they believe in. You can divide almost every story you read that allegedly shares information on airplane building into to camps: Valid testing that supports learning, and opinion or out of context stories that support myths. Only one of these will make your plane better.

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This division cleaves all discussion, any story can be put in one pile or the other.  What always gets me is this simple fact: Less than 20% of homebuilts are completed. I have been around Pietenpols a long time, and I would guess that their completion rate is far below 10%. What no industry magazine or salesman is going to tell you is that the completion rate, as a whole for our branch of aviation is actually dropping. Yes more planes get completed, but the sell many more these days. Given this fact, you would think that builders would all recognize that to personally beat the poor average, they have to make some smart choices, and a critical one is learn from valid tests, and don’t waste time listening to the same myths and old wives tales that lead 80% of previous builders to failure. But, for some reason, the myth mill still works every day, and people participate in it, directly sabotaging their own chances of learning and success

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It is somewhat frustrating to conduct a mountain of public tests, but they are cited less often than dubious sources from decades-old news letters. For people who wish to see real side by side thrust tests and dyno runs, get a look at this link to our testing page: Testing and Data Collection reference page. For Pietenpol builders who want to see that a 72″ prop doesn’t hold a candle to a 66″ one bolted to a powerful engine, look at: Pietenpol Power: 100 hp Corvair vs 65 hp Lycoming. If you would like to read about how most of the things said about “prop efficiency” are myths, get a look at this:The case of the Murphy Rebel, “eyeball vs. testing” I would hope that the next time the myth machine goes to work, someone will share a link to these pages, or even this story.

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Here is a simple example of testing and common sense from the last story link:

“Props with diameters of 74″ are only efficient on engines like the
Continental 65 with a low red line of 2300 rpm. Low rpm isn’t efficient in itself. A 65 Continental becomes a 75 continental with respect to power output by just a jet change and an RPM increase to 2600.  If turning the prop 300 rpm faster and using one with less diameter actually made less low speed thrust, than no one would have ever converted a 65 to a 75.”

Some pretty basic logic. I only ask people to believe what I can show them with tests and common sense like the point above. To counter this, the myth makers only have old newsletters and stories like “I heard a guy tried that once but it didn’t work.” Occasionally there will be input from a guy who touts a long dusty engineering degree as some credential as credibility for his favorite myth. If that is more valid than a specific test done in public, then I have a Unicorn to sell you.

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If you would like a simple example to destroy the myth that low speed aircraft have to have large slow turning props to have performance, let us take a look at some work from a man who only valued one thing in planes: Performance. This man was the greatest air racer who ever lived, and almost all of his work was done on planes that could be well powered by a Corvair. The Mans name was Steve Wittman.

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Let’s look at the plane below and the prop on it. It is Wittman’s “Big X”. It is a 4 seater powered by a 150HP Franklin. It was noted for having a very wide speed envelope.  Did Wittman use a big slow turning prop said to be efficient? No, he used a high rpm, smaller scimitar prop. This plane climbed at 70 mph, it had to have good low speed thrust, and it did. How long have people known that the only thing slow props have going for them is sound suppression? Well the photo here is from 1947.

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Below, the Buttercup. The photo is from the EAA museum where the plane was retired to after flying for 60 years. It is reported to have 3,000 hours on it. The prop is not the correct one, it is just for display. This plane will fly and climb at speeds well below the stall speed of a Pietenpol. it will also do 145 mph on the top end. How does it cover such a wide envelope with a C-85? Simple, it has a smaller diameter prop that it spins faster. For people who claim that high rpm props don’t make thrust, please explain what was making the thrust that drove the plane forward at 145 mph when the engine was turning 3,400 rpm. Again the ideas are not new, the buttercup was built in 1937.

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How about a slightly faster example? Below is a youtube link to Steve flying his Tailwind N-37SW, powered by a direct drive inverted Olds 215 V-8, bored and stroked to 262 cid. It has a 62″ diameter prop on it. It was cut down from a Cessna 150 aluminum prop. It climbed very strong and topped out at 3,600 rpm and 195 mph with out wheel pants. How do I know this? Because I flew in the airplane with him for a very vigorous flight in 1993. Notice that people who present myths always have a mysterious “guy who tried it”. I am essentially doing the same thing here, with the exception that I was there, my “guy” actually existed and was one of the greatest builders and pilots of all time, and, conversely, it worked for him. Other than those details, my story is just the same as any other internet myth.

http://www.youtube.com/watch?v=WsH-j4pF4fE

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Something I wrote about real aviators at the core of flight:

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“If you look at their lives close enough, all of the greats offer something to guide us in pursuit of the timeless truth of flying. Pietenpol teaches that we are more likely to find it in the simplest of planes; Lindbergh knew that you started your search inside yourself; Gann said that we will not see the truth directly, but you can watch it at work in the actions of airmen; and Wittman showed that if you flew fast enough, for long enough, you just might catch it. These men, and many others, spent the better part of their lives looking for this very illusive ghost. Some of them paid a high price, but you get the impression they all thought it was worth it.

While it is possible that someone who rents a 172 or even a person who reads Fate is the Hunter has some access, I honestly think that the homebuilder who dreams, plans, builds and eventually flys his own plane is infinitely more likely to experience the timeless truth of man’s quest for flight. All of the aviators who had some insight to guide you found it while they were in action, in the arena. If you inherently feel that you want to build a plane, you feel just like Pietenpol did. When you’re building it, you will find out how determined you are and what kind of perseverance you have. Lindbergh evaluated these qualities in himself every day. As you finish and prepare to fly, you will find others of enormous qualities and flaws, and you will learn to sort them and their counsel, as Gann always did. And when you fly your plane, and come to trust it because it is your creation, and you cut no corners, you will never want to stop, the way Wittman never did.” -ww-(2008)

Fuel Injection – Corvair flight engines reference page

Builders:

Here is one spot where we have collected a number of different stories on Fuel injection for Corvair aircraft onto a single reference page. Like the other reference pages, it is a central starting point on the topic, and easy to keep updated or make additions to. If you are interested in learning more about this topic, read on, there is a significant amount of information here.

If I were to pick a single topic that new builders are interested in, but know little about the applications of, It would be Fuel Injection. This is a topic dominated by misconceptions and myths. Here is a quick check: Do you think that a port fuel injection engine or one with a carb on a long intake manifold makes more power? Would you be surprised to learn that the evaporative cooling effect of the carbs fuel delivery can give it a significant advantage? It does, and to learn this and many other points on reliability, read on. Unlike much of the info on the net from armchair experts, the information below is straight from experience and testing…in aviation settings, not in cars.

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The information below is in the following order:

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1) Links to stories I have written on FlyCorvair,net

2) A full print of my Group numbering system #3700 EFI notes.

3) A reality check story from 2008 on EFI failures

4) Notes on Internet ‘experts’ you should beware of

5) A 385 mph EFI plane and some final thoughts.

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Above, a rear view of the Panther engine. Mounted on the intake is a Precision Mechanical fuel injection system. Initially, these was the planned fuel system for the Panther, but after careful evaluation, Dan Weseman opted to go with a very simple MA3-SPA carb. All of the aerobatic flights on video on the Panther site are done with a one barrel aircraft carb, not injection.

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1) Links to stories I have written on FlyCorvair.net:

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Click on the titles in color to read the full stories:

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Mechanical Fuel Injection Testing

Compares Precision and Airflow performance instalations

Fuel Injected Corvairs

stories on 3 running EFI engines

Group Sources for the new numbering system.

Covers that EFI is Group  #3700 and Mechanical injection is Group #3800.

Panther Prototype Engine 3,000 cc/120 hp to OSH

Another look at the Precision system

Corvair Powered Davis DA-2, w/EFI

The only successful flying EFI Corvair powered plane. A hard won achievement.

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2) A full print of my Group numbering system #3700 EFI notes:

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3700- EFI (Electronic Fuel Injection)

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Many people just arriving in aviation are interested in electronic fuel injection.  Some homebuilders are impressed with its performance in cars or have read about one of the handful of experimental aircraft flying with fuel injection. After listening closely to builders, I discerned their interest originated from five reasons: 1) They thought it would make the engine more powerful; 2) They thought it would reduce fuel consumption; 3) They felt that it would eliminate the possibility of carb ice and eliminate the need for carb heat; 4) They thought it would be more reliable than a carb, or; 5) They just wanted to try it. Experience has shown me that the first four are not true to any meaningful degree, and that #5 is the only reason that makes sense. If you are pursuing EFI for reasons #1-4, you are going to be disappointed, but if #5 is your motivation, then the project may be a success to you.

Let me first say that I am not against EFI, but I think that builders should know the facts before they pursue it. My background on EFI installations in planes is better than most. A guy who works on them all the time in cars, but doesn’t put them in planes, has a long way to go before he learns what he needs to know to be reliably and safely flying. I did a lot of work on Jim Rahm’s 427 cid V-8 Lancair IVP. It had the best EFI system in the air. We had the best people working on it, a nearly unlimited budget and experience that no homebuilder in his garage could match. It took a lot of very hard work to make it the reliable system. Just because Jim’s motor made 600 HP and you only want 120 HP doesn’t mean that solving the installation issues will only cost you 1/5 the time and money. And even if it did, we would still be speaking of time by the calendar years and money by the cubic foot. When I read discussions on the Net about EFI on experimental aircraft, I can quickly tell who has never assembled and flown a system.  95% of the advice on the Net is offered by people without flight experience. Out of the 30,000 experimental aircraft in the U.S., I am fairly sure that less than 300 of them have EFI. I cannot think of a single significant aviation record below 500 HP that is held by an EFI engine. There have been many clever people who put a lot of effort into EFI on planes, with little result. No matter what caliber of auto mechanic you are, experience says that you will find exceeding the performance of carbs or mechanical injectors very difficult, and EFI may never have the reliability record of the simple 1 barrel carb.

Out of the roughly 300 experimentals flying with EFI, the vast majority of them are using 1990s auto engines with EFI from the factory. In this case, the factory engineers did most of the work. If you think about it, there are very few motors like O-200s, VWs and Corvairs flying on EFI. And the ones flying can’t boast the flight record of carbureted engines. I have seen a number of these planes flying with 35psi fuel pumps inside the cockpit with barbed hose connections and hose clamps. No one should dream of flying things like this. Let’s examine the points one by one objectively to learn about the issues and make an informed decision.

1) I have seen claims that EFI makes the same engine 30% more powerful. Nothing of the sort is true.  Engines make power because they burn a mass of air mixed with the right amount of fuel. There is no way that an engine is going to inhale significantly more air because it doesn’t have a venturi carb. This advantage is slight, and would be well below 5% on an engine like a Corvair. To see any more difference than this, the cylinder heads and intake tract would need to be designed for it right from the start, by very smart people with a lot of sophisticated equipment (of the caliber found in Detroit factories). Slapping an EFI system on the Corvair will not have the same effect. Fuel injected motors are said to make slightly more power because the fuel is better atomized. But carbs, even simple ones, are surprisingly good at this. The amount of records still held in racing by carbs should tell anyone that the EFI power advantage is minimal. Carbs have a very serious advantage of vaporizing the fuel well upstream, and having the air/fuel mixture cooled and its density increased. In almost every case, this offsets any gain in power from atomized fuel. When running at power, Corvair intake manifolds are cold to the touch from vaporizing fuel. EFI does not have this effect.

2) EFI will not significantly reduce fuel burn in a Corvair engine. For best economy, engines need to run a lean mixture. EFI has the theoretical ability to atomize fuel slightly better allowing it to run slightly leaner mixtures than a carb could without detonating. In actual use, it is foolish to run an engine this close to detonation. Modern auto engines can do this because they have computer-controlled ignition tied to a knock sensor and the fuel injection. Without these devices, any significant fuel burn advantage is lost. Many of the well known auto power proponents, even those who work with computer controlled EFI engines, clearly state that EFI doesn’t significantly reduce fuel burn for a given HP in aircraft engines. The efficiency advantage in cars is gained by running in “closed loop” with air/fuel ratios near 14:1. Under this operation, the injectors are fine tuned by reading the O2 sensors many times a second. The reality that few new builders understand is that any engine running at 75% or more power has to be running an air fuel ratio of 12:1. At this setting, O2 sensors don’t reliably work, and the system will operate in open loop, forfeiting any efficiency gains while retaining all the complexity and vulnerability. I have never seen any EFI flight engine that will fly at cruise power in closed loop mode. They are all just operating off a set of pre-programmed values based on RPM and MAP. These can be very crude, as some aftermarket EFI systems have RPM increments as rough as 250 RPM. In cars this would be masked by the O2 sensor moderating the injectors, but it can’t when it is in open loop. It is technical reasons like this that allow carbs to often demonstrate smoother operation than EFI in experimental aircraft.

3) EFI is less prone to carb ice, but is not immune to this trouble. There are still conditions that can cause this trouble. Almost all injected engines have an alternate air source. Homebuilt aircraft in Canada are required to have heated alternate air no matter what the fuel system is, and there is good logic to this. For a more complete discussion of this, see the article on carb ice at the end of the Manual.

4) Many people feel that EFI will free them from things like carb ice, reducing their level of risk in flight. While the risk of carb ice would be reduced for a pilot too careless to use carb heat, many new risks are introduced. EFI requires high pressure pumps, regulators and lines; it can be stopped by a piece of trash in the fuel that a carb would easily pass; its numerous electrical connections are prone to failure by corrosion or poor crimping; and the whole thing is so electrically dependant that most people fly with two batteries. Contrast this with a gravity feed fuel system in a plane with distributor ignition which will run for hours on a small battery with no input from an alternator. You cannot focus on the one possible advantage of a system without considering all the downsides that come with it. Automotive EFI installations are reliable today because auto makers spent literally billions to make them so. Brilliant people in Detroit who are specialists in dozens of details of the installations and privy to incredibly accurate statistical data on failures allow them a great corporate body of experience to tap into with every installation. It is my feeling that anyone looking into EFI who states that it is more reliable is making an argument for the car, not what an individual homebuilder can do in a plane, where a single detail of installation may compromise the system.

My observations on reliability are simple: Any system that uses lower pressure fuel is less likely to leak. Gravity is better than 5 PSI, and 5 PSI is better than 40 ; any system that uses no electricity is better than one that uses  a little, and one that uses a little is better than one that uses a  lot, especially if the one that uses a lot needs it to be a  certain voltage; any system that has less parts and connections is less likely to  fail,; digital electronic connections, working a low voltages, are very sensitive  to corrosion, temperature, and vibration, things planes produce more than newer  cars.

5) Being an experimenter at heart and wanting to address the challenges of an EFI installation is a valid reason for trying it. You know a good, reliable and airworthy system is quite a challenge because you don’t see them often. Anyone who achieved this could be justifiably proud of his creation and would learn a lot along the way. A person who is motivated by this will be satisfied when it works, whereas people motivated by #1 – #4 are bound to be disappointed when EFI cannot live up to the overblown claims many armchair/Internet experts make for it. The only good reason to work on an EFI Corvair is because you want a challenge, and this is more important than finishing your plane soon, or operating at a lower risk level. This is a valid position, and I support anyone who knowingly makes it.

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3) A reality check story from 2008 on EFI failures:

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” A Christmas story”

 At 8 a.m. on December 24th 2008, I was driving my 175,000 mile EFI S-10 up I-95 at 75mph. I had promised my parents that I would make it to their house for Christmas Eve dinner. I had never had a bit of trouble with this EFI engine. Near Richmond, Va., it quickly died out, and I was only able to coax it into a truck stop at 10% power. A morning of diagnosis showed that the pressure regulator had died. It was not in an easy place to get to, no one had a replacement and the truck was worth maybe $500 before it was broken. I gave the truck to a 20-year-old tow truck driver wearing a Chevy hat and a Jack Daniels sweatshirt, as a trade for a ride to a car rental place. We got there 10 minutes before they closed. The driver asked me several times if I was really giving him the truck and if I really was from New Jersey. The experience was counter to many things he had been told about people from N.J.  After some reservation, he took the gift of a truck from a Yankee on the eve of the birth of Jesus to have special significance.

 Such a warning less failure in a plane might prove to be lethal. Note that aircraft carbs almost always run even when they are having an issue.  A good look inside Pat Panzera’s Contact! magazine issue #96 shows a destroyed homebuilt aircraft, product of a sudden EFI failure. Here is a story of a guy who may have felt that carbs and engines without O2 sensors were stone age. Maybe, but stone age tools are noted for reliability. I am glad the builder was not more seriously hurt. Over the years, a number of people have written to explain that they are going to engineer their own EFI systems, or use something called “shareware” to program one (the blind leading the blind on the Net). Out of perhaps 50 people who have written this, not a single one of them went on to produce a running EFI engine. Experience tells me that people who arrive with a big flourish and little consideration for what has been accomplished have a very low chance of flying anything.

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4) Notes on Internet ‘experts’ you should beware of:

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A modest search on the internet will reveal many people speaking about EFI for Corvair powered planes. Armed with the information I have printed above, you can debunk most of the claims people make. Still, there are people who present a case to new builders as if they are some type of experienced expert to be followed.

The internet is an odd storage device. I holds more old trash better than any landfill on earth, and it keeps it fresh, even long after the project was abandoned. Let me share by example: Don’t waste the time to look it up, but there is a long detailed website run by “Haynes Engineering.” Sounds official, but it was just one guy in a barn who had never built a flying plane before, offering a long how to session on putting EFI on a Corvair in a Zenith 601. I never met the guy, but I did email him several times, and he spent a long time on Mark Langford’s discussion list, where he had many fans who eagerly awaited Mr Haynes demonstrating all the things he promised from is Harley Davidson salvaged system. Although I offered to publicly test run his engine at a college, Mr. Haynes soon despised me, probably for not recognizing his brilliance. His website is all about putting a Corvair on a 601, but makes no mention of Our success with doing this, or my work at all.

If you have built planes, it was easy to see that Haynes didn’t know much about planes, but had the kind of ego that didn’t like admitting that. He was a foolish cheap skate, ‘rebuilding’ his engine with a used cam and worn gear, and using angle iron to build a motor mount. His EFI system had hard aluminum lines where it needed flex ones, and he spent a lot of time trying to use a little outboard starter. In the end, after getting many green guys excited, he couldn’t make the engine run, and instead started it for 5 seconds on starter fluid, and then wrote a post to the internet silmaltainiously declaring victory and quitting airplane building altogether. Does this sound like a stable person who you can learn from? Is it the kind of information that you want to bet your life on? This was years ago, yet I saw the website just last week, with no mention of the system never working or the whole aircraft project being abandoned.

If you are new to home building, the quicker you learn never to be distracted for real progress by day dreamers and fools without experience, is the quicker that you will learn what really works, and how to incorporate these skills into your own experience and your own plane. The internet will provide an endless stream of people like that. 80% of the people who start a homebuilt do not finish. Be determined to be in the 20%. One of the things that the 20%ers all have in common is not getting sidetracked by fools.

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5) A 385 mph EFI plane and some final thoughts:

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I’m known for advocating simplicity in aircraft engines. This recommendation comes  from my experience on the opposite end of aircraft powerplants. Above,  Arnold Holmes (host of CC#17,#25, #29) and I stand behind the engine installation on a V-8 powered Lancair IV-P.  This is an EngineAir package that I helped develop from 1993 to ’98. It’s 450hp, geared,  injected, intercooled and turboed, and features air conditioning. Get a good look at the size of the 5-blade MT propeller.

  Eventually, about a dozen of these took to the air. They were stunning performers. I flew  from Oshkosh to Daytona Beach in three hours and five minutes in our first airplane, N420HP. This aircraft is on the cover of Sport Aviation in July ’97. If someone suggests I don’t understand EFI, ask them if they have flown in a 385 mph EFI plane they helped develop and build.

 The development of this engine took the work of many clever, dedicated people, and one  guy with cubic yards of money, Jim Rahm. It worked, but taught me that homebuilders at all levels  tremendously underestimate the effects of complication, primarily its delays and expenses.  Whenever I read discussions about electronic injection or computer controlled engines, I  can tell in an instant who has no practical experience with attempting to prepare these  systems for flight.

Evaluate your interest in fuel injection carefully. for most builders, it is a distraction, for some it will become a stumbling block, for a tiny number of people it may become a dangerously complex part of their plane, a part they thought would be the most reliable, but turned out to be the part they trust the least. This is pretty far from the goals that most people have when the first think about putting EFI in their plane.-ww

Getting Started in 2013, Part #2, Group numbering system

Builders,

I have a numbering system that I use for the engine parts that counts every single piece in the flight engine, and puts them in groups that make sense for builders getting organized to build their engines. In this series, I will introduce this nomenclature I use to keep track of in-house production engine to people building at home. When you see a little bit of how its organized, it will make a lot of sense. I am going to bring it in on each segment, and pause to discuss how it works as a system. I have had it for several years, and long-term I would like to integrate it into how builders plan out a build. Later on I will show you the critical path chart that works with it and a decision tree, but for now, lets look at the building block with the crank system as a “Group.”

I have the Flight engine broken down into 38 “Groups” Numbered from Group 1000 (Crankshaft) to Group 3800 (Carbs). As you look at the numbers below, note that all the numbers in the Crank Group (1000) fall between 1000 and 1099. Now, you don’t need 99 part numbers for crank things, I am just keeping a natural spacing. The next group in line is Camshaft Group (1100). We will get to that next. But for now, see how every part in the crank system is accounted for. Note that the rod and Main bearings are in this group because they are dependant on is the crank is new (standard bearings) or Reground (.010″ Bearings etc.) The list can function as a checklist for a builder getting everything ready for an assembly, or one just planning a very careful budget. In about a second, someone will kindly suggest an excel spread sheet, but keep in mind I am a real Troglodyte, and a sheet to me belongs on a bead and an attachment is something I have for my dog. For right now, lets keep the focus on the parts and system, and if individuals want to organize it a little later, that’s fine. There is a lot of later growth potential in the system, where we make short you tube videos for each section, etc, but for now, lets remember that the goal is to build an engine.

Crank group (1000)

1000- Crank (8409 GM or Weseman new Billet)

1001- Crank gear

1002- Crank gear key

1003- Crank gear gasket

1004- Rear keys -2-

1005- Fuel pump eccentric

1006- Spacer

1007- Bronze distributor drive gear

1008- Oil slinger

1009- Main bearings

1010- Connecting rod bearings

After a builder gets all the stuff organized, he can check off  Group 1000 and move forward. To assemble a case, you need to have Groups 1000, 1100 and 1200 (Case) and we will get there shortly. If a builder has a specific question about a part, ask away, we will be able to refer to them by specific number. Notice how number 1009 doesn’t stand for a specific brand or size bearing. Today, the recommended main bearing is Clevite, and the size again, depends on the crank size. If next year there is a different bearing that testing shows to be better, then we can reference this in an update of the single 1009 number, but 1009 will always stand for the main bearings. Keep in mind that the goal is to give an overview of building the engine, and this little post is already 600 words. I have very detailed notes for every single part number, but I want builders to take in the big picture for right now. My flight instructor was very fond of saying “WAKE UP, IT’S TOMMOROW!” any time he caught you daydreaming in the cockpit. Same applies to making a plan for getting your own personal engine to advance.

If you’re looking at shipping your core crank out by Saturday, pull it out of the engine and get going. If you have a small gear puller you can remove 1005, 1006, 1007 and 1008 in one shot. Let the pro who is doing the crank take the 1001 gear off. Get a plastic bag, a few feet of old carpet, a strong cardboard box and a roll of shipping tape and get it wrapped up. What you do this week makes a difference on whether your working or watching at CC#25.-ww

 

Fuel Injected Corvairs

Note to readers coming from the Cub Crafters site: This information is not directly applicable to Lycomings. The 6% power increase came from a major change in the intake configuration, not from the EFI. Look at 360 Lycomings; Yes most of the ones with a carb are 180HP and most of the injection are 200HP, a 10% gain, but this is ignoring the fact that the 200HP models (the -As and -Cs) have a very different angle valve head and a tuned induction system. Note that the 360s that just change from a carb to injection, (the -B series) remain at 180hp. There is no magic power in FI.  Also note that all Corvairs in the last decade all have electronic ignition. If a Lycoming has a perfect set of mags and they are replaced with electronic ignition, there is no reason to expect a measurable peak power increase.  The far easier way to get a small power increasein almost any motor without adding any complexity is to turn it slightly faster. -ww.

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Friends,

Here are some notes and photos of five fuel injection systems for the Corvair. The first three are electronic systems, the latter two are mechanical injection. Fuel injection is a topic that many builders ask about.  I think a lot of the interest is generated by the awareness that high performance certified aircraft have mechanical fuel injection. A number of builders have learned that these systems are comparatively immune to carb ice. Beyond this, very few people have a good concept of the pros and cons of these systems vs. carbs. Even guys who know a fair amount about engines often miss important realities about the applications of these systems. This post gives a general overview, and covers details that are rarely discussed when builders bring up the topic of injection.

Electronic injection is the type of system that modern cars use. There have been a number of auto engine conversions that came from cars that had EFI that have gone on to fly in planes, and some suppliers to certified engines are just starting to look at EFIs fitted to Lycomings. What gives modern cars good mileage, long plug life, low emissions, etc.,  is the ability of the EFI system to operate in closed loop mode. It does this almost all the time the car is cruising down the road. When it is not doing  this, it is operating in “open loop mode” and falling back on the computer’s pre-programmed data that says ‘at 3150 rpm and 26.5″ MAP squirt in so much  fuel.’ In open loop, much of the advantage of EFI disappears. Up to here,  what I have typed falls into the category of  “Lots of people know this.”  Here is  the corollary only a few people understand.

In aircraft applications, the EFI systems almost never operate in closed loop. If you are going to cruise your aircraft at 75% power, it will spend its whole time in open loop. This is true with liquid cooled engines, but  really true with air cooled ones. Very few engines run with air fuel ratios of  14.7 to 1 at high power settings. They mostly run 12 to 1, or richer, and  O2 sensors have a hard time getting the loop to close at rich ratios. Sure,  there are exceptions to this, like wide band sensors, but you really cannot  compare a made at home system to a 2007 Corvette with perfectly tuned knock  sensors, 1 million lines of code in memory, and the ability to look at  individual cylinder exhaust pulses as they pass the O2 sensor. Even still,  GM knew that 75% sustained power in the Vette would be about 155mph, and the car  would spend .002 percent of its life there, so it’s OK if it is in open loop at that point.

After CC #9, I got Mark from Falcon to walk over to Jann Eggenfelner’s hangar. Jann is the king of Subarus, and like it or not, most people concede that he has flown more different types of EFI than anyone else. I know him  fairly well, and he is very smart, and unbelievably tenacious. With Mark’s OEM background and Jann’s flight experience, they had a very detailed high speed  data exchange. The recurring point that Jann kept coming back to is that no system, including the Subaru OEM stuff, will reliably operate in closed loop at aircraft power settings. In open loop, EFI begins to look like a very complex, high pressure, electrically dependent carburetor.

Above, the EFI 2,700cc Corvair built by Mark at FalconMachine.net in 2007, at power on my dyno. The urethane wheel directly reads foot pounds of torque off the digital scale. Note that this engine is using headers with collectors. We also tested it with cast iron manifolds and mufflers. It has distributorless ignition. Six LS1 coils are mounted on the sides of the black airbox. After a lot of careful calibration runs, this engine achieved a 6 percent power increase over a carbureted Corvair. Merely saying this will certainly activate the keyboards of armchair EFI experts, but it’s simple measured facts. Before questioning the test methodology or results, consider that Mark has earned his living with these systems for the past 20 years and the instrumentation included such niceties as a $500 laboratory grade digital oxygen sensor. Anyone who says that adding EFI to an engine like a Corvair will add 30% more power is just making their information up. The system above was tested a number of hours but was not flown. The controller on this was a Tracy Crook unit. This engine was equipped with equal length intake runners. It was laid out to fit in a 601/650 cowl.

 This is a redundant ignition, electronically fuel injected, fifth bearing, 2,700cc test engine built by Roy at RoysGarage.com in 2007.  It features coil on plug technology and throttle body injectors along with a rear mounted 40A alternator. It is mounted on Roy’s 701. It was run and tested, but not flown. Roy also has extensive experience with digital EFI systems. This provided good data, but in the end, Roy thought about the complexity he was applying to a very simple aircraft and chose to finish the aircraft with a simple gravity feed carb instead.

My thesis on EFI in 5 simple points:
1) Any system that uses lower pressure fuel is less likely to leak. Gravity is better than 5 psi, and 5 psi is better than 40. EFI runs at high pressure.

2) Any system that uses no electricity is better than one that uses  a little, and one that uses a little is better than one that uses a  lot, especially if the one that uses a lot needs it to be a  certain voltage, like digital EFI.

3) Any system that has less parts and connections is less likely to  fail. Digital electronic connections, working at low voltages, are very sensitive  to corrosion, temperature and vibration, things planes produce more than newer cars.

4) Almost all the things that EFI advocates hope for, HP increase, smoothness, fuel efficiency, and reliability, will prove elusive or minimal.  Before debating this, seek out a single flying system that will go into a closed loop in cruise flight. Realize that monitoring voltage and fuel pressure is not a work load reduction from using carb heat.

5) The only good reason to work on an EFI Corvair is because you want  a challenge, and this is more important than finishing your plane soon. This is  a valid position, and I support anyone who knowingly makes it.

Let me introduce a man who personifies point number 5, Rex Johnston. As far as I know, Rex is the first guy to ever fly an EFI system on a Corvair powered aircraft. This makes him someone special, because there were a lot of hurdles to jump over. His Corvair powered plane is a Davis DA-2, a sporty little two-seat sheet metal aircraft. Rex’s work is an outstanding example of building to meet a challenge that you personally feel. He was not after some illusive performance goal, he was just looking to challenge himself and learn a lot. Hats off to Rex.

Above, the underside of Rex’s plane. His system is a Holley Projection throttle body unit, that Holley originally sold for 258cid Jeeps. Rex’s  engine is a 3,100cc Corvair. Notice that it still has carb heat. A project like this isn’t for everyone. It takes significant experience building to be able to develop and flight test a complex set of systems like this.

The standard for aircraft injection are mechanical systems. These use no computers, they work entirely on a balance of pressures and flows. They meter fuel very accurately, and offer instant throttle response. They typically operate at 25 psi, somewhat lower than EFI. Unlike EFI, they are not sensitive to fuel pressure changes, and they do not need an external pressure regulator. By design, they are always operating in open loop mode. Because these systems have been used on aircraft for half of the history of powered flight, they are fully understood and developed.

The above photo shows an Airflow Performance mechanical fuel injector specifically calibrated for the Corvair. For size reference, a core Stromberg carb is at top left in the photo. Below it is the gold flow divider. One of the installation advantages of mechanical injection is the extremely small calibrated nozzles. Packaging six electronic injectors that will fit in a tight cowl is challenging. Mechanical injectors have an 1/8″ pipe thread on the bottom and are roughly 1/4 the size of electronic injectors. Airflow performance is owned by Don Rivera, a very smart guy who has owned and driven land-based Corvairs. This system is made in the U.S. The parts for this system cost over $3000.  Corvair builder Sarah Ashmore is putting one of these on her Personal Cruiser airframe. Her heads were modified for the injectors by Mark at Falcon. She works in the aerospace industry and made the choice to equip her aircraft with a system that met her specific goals.

Above is a photo of a Precision mechanical fuel injector.  The pictured unit is a port injector, but they also make a very compact unit that has the same quality, but has just one injector built into the body of the unit. The system does not require any modifications to the Corvair’s heads or intake, as the unit bolts onto the same flange as an aircraft carb. Peter Nielson of precisionairmotive.com is our engineering rep who has supplied us with a test unit, which we are now testing on a 3,000cc Corvair. This system is about $2,500. Precision knows quality, as they produce parts for and service certified fuel systems. We will release more data as we move through the tests. We are planning on flight testing this on Woody Harris’ 601, and Dan Weseman is planning on using the aerobatic capability of the system on the prototype of his new Corvair powered design, the Panther.

Today, 99.75% of Corvair powered planes use carbs. However, I think the Corvair is a good platform for fuel injection, and there are a small number of airframe applications that could really benefit from a fuel injection system. While there has always been a lot of talk about EFI, only a rare few clever and persistent builders like Rex Johnston will see the project through. I personally feel that the mechanical systems offer the best reliability and most proven track record, having flown in many demanding settings on other engines. As always, the proof and the progress is in the hands of the builders, the people In The Arena.

Thank you,

William

:)