Zenith 750 / Corvair reference page, October 2013
Builders,
Here is a single location page that has a great number of links to information specific to the Zenith 750 / William Wynne-Corvair Combination. It is a particularly good match, we have a number of different ways to approach it that serve the needs of many different builders, and it is a success story that builds on our 10 year history of working with Zenith builders, starting with our own personal 601XL in 2003. Since then we have assisted more than 80 builders to complete and fly their Corvair powered Zeniths. In the coming years these will be accompanied by an ever increasing number of 750’s.
If you already are working on your Corvair, this page will have information you have seen already on our websites, but I have included it so that this page can function as a ‘stand alone’ guide for 750 builders who have just heard about our work with the Corvair. Our approach to serving builders is different than typical businesses geared only to sell things to consumers. Our goal is to assist you on your path to becoming a more skilled aviator. The products we sell support this, but simply getting you to buy things is not what I am in aviation to accomplish. If you would like to start with a simple three page spec sheet on the engine, read this link first: Basic Corvair information
This page is broken into the following sections:
1) Introduction
2) Engine and build options
3) installation components
4) Support for builders
5) Flying 750’s
6) Builders in process
7) 750 flight data and safety notes
8) who is WW?
9) Comments on dangerous trash.
At the end of each section there are links to supporting stories that have expanded information on concepts discussed in the section. Take your time and study it carefully.
I will be glad to answer further questions just email WilliamTCA@aol.com or call 904-529-0006. You can also check our two websites, http://flycorvair.net/ , http://flycorvair.com/ . The first is our ‘newspaper’ the second is our ‘library’ and ‘store.’ The links below are stories that already appear on these two sites, they are just arranged here to support this introduction to Corvair power for 750 builders.
Above, the flying 2850cc Zenith 750 built by Gary Burdett of Illinois. It has our full complement of Zenith installation components and one of our production engines.
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1) Introduction:
The Corvair has been flying since 1960, and I have been working with them as flight engines since 1989. It is a story of careful development and testing, a slow evolution to the engines we have today. It is ‘old and proven’ rather than ‘new and exciting.’ If that approach appeals to you, read on. There is a lot of material here, and it isn’t something you are going to absorb in one quick scan. Frankly, your engine selection deserves careful consideration, and it isn’t the kind of decision you should make based on a 4 page sales brochure.
Corvairs have proven themselves to serve a very broad variety of builders. Many alternative engine options for the Zenith are offered only as a “buy it in a box” import, more of an appliance than a machine, with little or no consideration of the builders, skills goals, needs, budget or time line. The Corvair has options to address these valid considerations, because your power plant should conform to you, not the other way around.
This said, Corvairs are not for everyone. In the 25 years I have been in the EAA and working with builders, the Corvair has always been very popular with ‘traditional homebuilders’, the people who have come to experimental aviation to discover how much they can learn, understand and master. The expansion of the EAA has brought more of these builders, but it has also brought a great number of people incapable of distinguishing between mastery of an aircraft or an engine and just merely being its buyer and owner. People who’s consumer mentality and short attention spans are better suited to toy ownership than mastery of skills and tools in aviation. Corvairs, and perhaps experimental aviation, are a poor match for such people. Many salesmen in our field will gladly sell anything to anyone with green money. I am an aviator, not a salesman, and the gravity of the subject requires more frank discussion and ethics than many salesmen bring to the table.
If you came to experimental aviation to find out how much you can master, not how little, then you are among the aviators who follow Lindbergh’s timeless 1927 quote: “Science, freedom, beauty, adventure: what more could you ask of life? Aviation combined all the elements I loved.” Even if you are brand new to aviation, I am glad to work with you. I have a long history of working with builders of all skill levels. We have a number of successful builders out flying their Zeniths who are the masters of both their airframes and engines, who had never changed the oil in a car before building their plane. If you got into experimental aviation just to buy stuff, then any salesman will do just fine for you. If you got into experimental aviation to learn, develop your own skills and craftsmanship and make things with your own hands, then who you work with really matters. You can’t become and old school homebuilder / motor head by buying things from salesmen. They have nothing to teach you. What you will do in experimental aviation is not limited by what you already know. It is only limited by what you are willing to learn, and selecting experienced people to learn from. If you are here to learn, I am here to teach. It is that simple.
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a) – Complete Lindbergh quote is here: The Quote, 1927, C.A.L.
b) – Explanation of machines vs appliances : Machines vs Appliances Part #2
c) – Story of real engines vs ‘ideal’ ones: Unicorns vs Ponies.
d) – An example of our ling standing working relationship with Zenith: Friday out of shop until 4pm.
e) – A direct explanation of what makes my work different than typical LLC’s : 2011 Outlook & Philosophy
f) – A moving statement of philosophy: Sterling Hayden – Philosophy
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Above, the 3,000 cc Corvair, configured for a Zenith 750. An inherently simple engine, It’s opposed six configuration makes it the smoothest of available power plants. It has outstanding cooling because GM put a tremendous amount of cooling fins on it and gave it a factory CHT redline of 575F. All of our engine parts are made in the United States.
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2) Engine and build options:
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If you are new to Corvairs, lets quickly cover some ground: General Motors made 1.8 million Corvairs. brand new parts, including billet cranks, forged pistons, valves bearings, virtually every single part inside is currently made and readily available, and will remain so. Rebuildable Corvair engines are plentiful, and much easier to find that Lycomings or Continentals. We have been working with Corvairs for 25 years, and there is no shortage of core engines or parts. If you doubt this for a second, Google “Corvair engine parts.”
The Corvair makes an outstanding aircraft engine because it is a simple, compact, direct drive, horizontally opposed six cylinder, air cooled engine. It is robust, and ‘flat rated ‘ from it’s automotive output. The engine runs equally well on automotive fuel and 100LL, and it does not care about ethanol. In its 53 year flight history, more than 500 experimental aircraft have flown on Corvair power.
The engine can be built in three dispacements with three respective power outputs. They are 2,700cc / 100HP, 2,850cc / 110HP and 3,000cc / 120HP. The two smaller displacements weigh 230 pounds, the larger actually weighs 8 pounds less because it uses lighter cylinders. All engines are completely rebuilt from very high quality parts before flight. They are not just removed from cars. The parts we use are specifically selected to convert the engine for the rigors of flight use. Forged pistons, Inconel valves, chrome rings, ARP rod bolts and many other components are upgraded in the rebuild.
To absorb the propeller and flight loads a “5th bearing” is added. It is a billet housing with a very large bearing from a V-8, bolted on the end of the case.The ignition is redundant and utilizes two 40,000 volt systems, one driven by digital electronics the size of a match book, the other by a traditional set of points. The engine is direct drive, it has no complex reduction unit. It makes good thrust because it has more than twice the cubic inches of a Rotax 912. All of the systems on the engine are intentionally patterned after those on Lycomings and Continentals, because they are the model of success in proven aircraft power plants. People who do not acknowledge certified engines as excellent models of success are often just zealots. To succeed in experimental aviation you need dispassionate information not emotional opinion.
One of the unique features of the Corvair is that it can be built at home, from our information and parts and a locally acquired rebuildable engine, or it can be purchased from us, test run with logs. 90% of current builders are building their own engine at home. Only 10% of the builders opt to have us build their engine. We have happy to serve both builders. In either case, Corvairs are the best match for builders who want to understand and be the master of their engine.
Because of the plans built vs production engine nature of the Corvair, there are large variations in how much builders budgets run. Below is a quick look at the differences. Keep in mind, these budgets are for first class, completely overhauled, zero timed engines with 5th bearings, starting, ignition and charging systems. We have clever builders who have built and flown engines for less than $3,000, but this not representative of main line builders. The numbers below are much better for Zenith builders to budget on.
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2,700cc / 100HP typical homebuilders budget: $6,500- Same engine assembled and run from us $9,750
2,850cc / 110HP typical homebuilders budget: $7,500- Same engine assembled and run from us $10,750
3,000cc / 120HP typical homebuilders budget: $8,500- Same engine assembled and run from us $11,750
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If you are attracted to the concept of building your own engine, but have not built motors before, Good. About half of our builders have never built any kind of an engine before. Our main work is teaching people what we know and providing the parts to work with. Our system does not require anyone to be a machinist nor to have previous engine experience.
The procedure of building an engine in your shop follows this format:
1) Get a conversion manual and DVD’s from us, use them to find a rebuild able core engine locally. Disassemble this engine following the steps in the DVD.
2) Send the crank and heads to our approved facilities for rebuilding and modification. They come back ready to ‘bolt on.’ Other parts of the engine are cleaned and inspected. The parts to convert the engine are ordered from us, many of the standard rebuild parts like lifters and gaskets are available from local auto parts stores. We do not ‘middle man’ anything you can directly buy.
3) Assemble these parts according to the manual and DVDs. There is no machine work required, only basic tools are needed, and a few specialty tools like a torque wrench. Many builders attend our free Corvair Colleges and directly learn hands on skills. You can even bring your parts and assemble them under our supervision, and test run your engine on our equipment. College attendance is a plus, but not required. Our methods work without direct training; a good number of engines are built and flown each year by builders who have never met me in person.
4) The test run serves several purposes. We teach people to build one of three specific models, and we teach them to use specific parts. Not only are these proven, but it also allows me to verify from a remote location that the engine was assembled correctly. A builder can report his static rpm, CHT, oil temp during the test run with his Warp Drive prop at the specified setting, and I can confirm the output and assembly of the engine without seeing it personally.
If you would like a sample of the information on working your way through the above four steps, get a look at this: Getting Started in 2013, part #1, Crankshaft process options.
I have broken down building a Corvair and installing it on your airframe into 42 “groups”. The previous link is about ‘Group 1000’ the crankshaft. If you would like to look at every part that goes into a Corvair, along with the conversion parts we sell, look at Groups 1000 -3300 at this link to our catalog: http://www.flycorvair.com/products.html
All builders get started with a conversion manual. The first part of the above link is about manuals and DVD’s. The direct link to the manual is: http://www.flycorvair.com/manual.html. almost all builders looking for a rebuild able engine also order the Disassembly DVD, which covers core engine selection visually. The direct link to it is: http://www.flycorvair.com/videov.html We encourage everyone to get started with information, even if you are pretty sure you would like to purchase a production engine from us. If you eventually buy an engine from us, we directly reduce the price to rebate all the money you spent on manuals and DVD’s.
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a) – Corvair Weight story: Corvair vs O-200…. weight comparison
b) – Samples of our production engines: 2012 Corvair Engines For Sale: 100, 110 and 120 HP
c) – For an explanation of ‘flat rating’ and a 750 engine build : Shop perspective: Mastery or ?
d) – A story about engines running on our hangar Dyno: http://www.flycorvair.com/thrust.html
e) Engine of builder now working on 750 airframe: World’s Strongest 3,000cc Corvair, built by Greg Crouchley
f) 3,000cc engine we built for 750 builder Larry Hatfield: 3,000cc Engine Running
g) A story about the evolution on 120HP Corvairs: 3,000 vs 3,100 cc Corvair engines.
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Headed to the 2012 Zenith open house, six of our powder coated 750 mounts. All of our mounts are welded in house, all of our parts are made in the United States.
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3) Installation Components for the 750:
We provide every single part it takes to install a Corvair in your 750. You can buy them one at a time, or all at once. Ninety percent of these parts are common to our Zenith 601/650 installation, which has been successfully flying for a decade. Only the mount, the diameter of the prop, and the size of the air inlets is different. Our Zenith installation manual detail how and why each of the installation components are installed on your airframe.
The installation does not require any modification to the airframe fuel system like most EFI engines do. Being air cooled and carbureted, it is one of the easiest engines to install. Many companies that are good at selling things are poor at teaching things, like how to install their products. Teaching is the very cornerstone of my work, I am a skilled writer, we run Corvair Colleges, and we have a simple engine. All this adds up to a comparitively easy engine to install. There is no need to rush it, but I can do it working in one long day.
Installation part numbers are Groups 3400 through 4300 in the second half of our numbering system. Get a look at this link: http://www.flycorvair.com/products.html From that list, you can see that the major installation parts for a 750 are: #3601(S) intake manifold, #3901(A) Stainless exhaust, #4002 spinner bulkhead, #4003 Warp Drive prop, #4101 baffle kit, #4102 nose bowl, #4103 cowl kit and a #4201(B) mount. The other smaller items listed are detail in our Zenith installation manual. All of the above parts have links to stories through the products page, but just for an overview of a single part, look at this link: Zenith 750/Cruiser Mounts. P/N 4201(B)
Many people new to building initially think that very economical engines like the Corvair must also be inexpensine to install. In reality, the cost of items like motor mounts and cowls are not affected by the cost of the engine they mount and house. A mount for a $30K UL-350 and a $7K Corvair have about the same amount to tubing and welding time in them, and thus cost about the same. Most engines for Zeniths have installation kits that run from $4,000 to $6,000. The Corvair is near the bottom of this range, but the savings of using the Corvair is in the engine, not the cost of installing it. Builders can save a significant amount of money by fabricating many of the parts like #4103, but most people are near the finish line at that point and opt to buy it and save the time. Exact cost on the installation parts varies a bit, I will be glad to review it with builders after they study the installation manual.
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a) – For an example of 74 years of aircraft welding talent: Zenith 601/650 Motor mounts, P/N 4201(A)
b) – To learn about the Stainless exhausts we make: Stainless Steel Exhaust Systems
c) – A 2008 look at how we developed the 750 installation on one of the first kits:
http://www.flycorvair.com/750.html
d) You tube video of an engine we built running on a 750 fuselage, 2009: http://www.youtube.com/watch?v=y_1ov0DAbe8&feature=plcp
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An overhead photo of a CH-750 installation we did in 2009.
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Above, 2004 at Oshkosh: Next to our personal Zenith N-1777W, I explain our dual ignition arrangement two executives from Falcon insurance, The EAA’s provider. To offer real support, an alternative engine provider must be an effective advocate for his builders on many fronts, including meeting the requirements of underwriters. Just being an engine guru is not nearly enough. Corvair engines that follow our design, including to ones assembled by builders, are fully insurable at the lowest rates, right from the first flight, because they have an outstanding safety record. Having good effective hands on support is a critical element in this outstanding record.
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4) Support for Builders:
Beyond the basic engine and installation components, we offer many forms of support to Zenith builders:
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a) We have a very detailed Installation manual for all Zeniths: http://www.flycorvair.com/601im.html We also have a flight operations manual with specific test flight plans and procedures: http://www.flycorvair.com/ops09.html
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b) we hold 4 free hands on technical seminars called “Corvair Colleges” every year. This includes an annual College held in Mexico MO at the Zenith Factory timed to coincide with the factory open house in September. For an introduction to Colleges, read this link: http://www.flycorvair.com/cc21.html An overview of upcoming colleges is at this link: Upcoming events, Airshows and Colleges #26-28. If you would like to see video of a College, here is a link to Corvair College #17 http://www.youtube.com/watch?v=wfa85e3ibI4&playnext=1&list=PL1D40A102EC2A194D&feature=results_video
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c) The “Zenvair” group is a separate on-line peer-to-peer discussion group just for Corvair/Zenith flyers to directly and freely share information and data with each other in a civilized productive format. The link is : ‘Zenvair’ Information board formed This is very effectively moderated by Zenith/Corvair builder and flyer Phil Maxson.
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d) Woody Harris, subject of this story: Zenith 601XL-2,850cc, Woody Harris Is our west coast representative. Although we have held 5 Corvair Colleges in California, including 2 at Zeniths west coast facility Quality sport planes, we only make one trip to the west per year. Woody covers all the shows and events from Arlington to Copper State when we can’t be there.
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e) I am the last guy in aviation who still makes free house calls. Over the years I have made more than 400 in person visits builders projects. I travel extensively, and go out of my way to include builders workshops on these trips. These stops and the colleges allow me to really understand the needs, strengths and dreams of rank and file builders that no one can read in email or at an airshow. for a sample, read this story: Corvair House Call, Range: 335 miles.
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f) By my continued advocacy and industry relations, Corvairs have full insurance, at the lowest rates, available from a number of sources. If you would like to find out more Contact Bob Mackey, VP of Falcon insurance, The EAA’s designated provider, seen on the left in the photo above.
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g) Over the years, we have built a very tight knit community of like minded builders. If you read this story about fools at our county airport: A visit to the insane asylum, and it sounds like your airport, and if your local EAA chapter is devoid of homebuilders and filled with negative people, you will find the Corvair movement to be a powerful antidote. Many Corvair builders catch several colleges a year, there they find positive, outgoing, energetic builders, effectively making the Colleges their “local EAA chapter” We have worked very hard to attract outstanding people interested in accomplishing their goals. I go out of my way to encourage new builders but I am intolerant of people who are compulsively negative. I am willing to be a cheerleader, but not a therapist.
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Doug Stevenson’s 750, powered by a 3,000 cc Corvair engine in California. This was the first Corvair powered 750 to fly.
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5) Examples of flying Corvair Powered Zenith 750s:
Doug Stevenson : Flying Zenith 750 w/3000cc Corvair, Doug Stevenson, California
Jeff Cochran: New “Zenvair-750″, Jeff Cochran, 2,850cc engine, N750ZV
Gary Burdett: Zenith 750 Flying on Corvair Power, Gary Burdett, Illinois
first story: Gary Burdett, 2,850cc Zenith 750, now flying. (engine selection)
Tom Siminski : Flying Zenith 750, Tom Siminski, 2700cc, PA.
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Above, Coenraad Van Der Merwe at the controls of his 750 during the first run of the 2,700cc Corvair he built for it. In spite of a busy work and personal schedule, he completed the airframe and built his engine in 18 months. Electing to build your own engine need not significantly increase the length of your build. In many cases, the vastly lower cost of this option compared to other engines allows the aircraft to be completed years earlier. Money, not time, is the limiting agent in most aircraft builds.
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6) Examples of Builders working on this Combination:
Coenraad’s 2,700cc: Running Zenith 750, Coenraad Van Der Merwe, CA
Blain Schwartz’s 2,850cc: Zenith 750 Builder Blaine Schwartz video on you tube http://www.youtube.com/watch?v=B4HwntCo2-I
Rodger Grable’s 2,850cc Corvair College #23 – 2850cc Engine, Roger Grable, CH-750 Builder
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7) Operational Data for this combination:
If you would like to read a story about detailed flight data collection on a 2,850cc 750, check out this link: CHT part #5, flight data from Zenith 750 . It is an example of the type of information exchanged on our ‘Zenvair’ group. If you are attracted to a builders group that is made of intelligent thinking people, you will fit right in with Corvair builders.
If you would like a single example to effectively demonstrate that I am an aviator not a salesman, it is the type of data that I discuss with builders. No salesmen will acknowledge accidents nor difficulties that involved their products, even circumstantially.
Conversely, I am here to teach people what they need to know. I have a long history of writing about subjects that salesmen wouldn’t touch with a 10 foot pole. I write about accidents and friends I have lost, honest mistakes people made and things you can learn from them. Just about everything know in aviation cost someone dearly to learn. If you are unwilling to talk about these things in plain language, people are doomed to repeat them.
For an example of plain speaking, I conducted an in person investigation of an accident on Doug Stevenson’s 750. It had an off airport landing on it’s third flight, and was damaged. It was caused by fuel exhaustion. You can read the whole story at this link: http://www.flycorvair.com/stevenson.html . Doug made a simple mistake., but he was man enough to admit it, and he wanted others to learn from it. As the leader of the Corvair movement I long ago set the ethic that we don’t demonize men for honest mistakes, we work with them to investigate and teach others. Doug repaired the airframe and we tore the engine down and internally inspected it. His aircraft is back flying and a proven performer now. As you read the report, keep in mind that I am a graduate of the same Embry Riddle degree program that most NTSB accident investigators. The data I collected, including the video, was taken into the official report.
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Above, A photo taken at Sun n Fun 2006. My wife Grace Ellen and myself, in front of the first Corvair powered Zenith, our own N-1777W. The plane was the first XL model with conventional gear. Grace is a skilled pilot in her own right. She has been a pilot longer than I have, holds more advanced ratings and owns two aircraft. As a point of ethics, we do not promote, advocate nor sell things we have not personally flown behind.
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8) Who is William Wynne?
Modern consumer sales logic dictates that that business should ‘de-personalize’ themselves so consumers find nothing objectionable about the provider while they are spending money. That model may work elsewhere, and even have advocates experimental aviation, but I don’t buy it. I contend that Aviation is a different arena, and who you are dealing with, and their ethics, experience and perspective matters.
Building a plane or an engine is a marriage of sorts between the builder and his airframe or engine company. I believe that it is best if everyone goes into it well informed with their eyes wide open. I am always surprised how few people even Google the name of a person they are thinking of working with. You don’t need to see eye to eye with them on every point nor even love them, but the relationship must absolutely have trust and respect operating in both directions. In 25 years I have seen many builders try to justify buying a product from a provider they didn’t really trust. It never works out. It doesn’t matter how good it looks, what it costs or how great it is supposed to work, if it is from a bad guy, it isn’t worth buying.
I could write a quick paragraph about how I am a pilot, a 22 year A&P mechanic, and that I hold both an AS degree in Maintenance and a BS in Professional Aeronautics (accident investigation) From the worlds #1 aeronautical university, Embry-Riddle , but I don’t think that any of that explains my commitment to builders nearly as well as the flying planes of our builders and things we have accomplished. Henry Ford said “A man can not base his reputation on what he says he will do; only what he has done.”
I am plain spoken. to understand why, read the ‘Effective Risk Management’ story below. I have many friends who are experienced aviators who value plain talk. This type of speech also tends to offend people who dabble in aviation and would rather read polite things that align with their pet opinions. I am in aviation to share experience builders need to know, not say things people want to hear. Below are a selection of stories, some humorous, but all with a point, that give people a better understanding of who I am. From there you can decide if you choose to work with me as your engine mentor.
a) Fixing America is going to cost each of us $1.69
b) Greatest Book on Flying Ever Written, (Is your life worth $16?)
c) In defense of plain speaking……
d) Turtles and Cell Phones, 6/24/13.
e) A thought on Easter….
f) Happy Father’s Day William E. Wynne Sr.
g) Effective Risk Management – 2,903 words
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9) Notes on trash from Bankrupt LLC’s:
Not all things called a Corvair represent my work or designs. Over the years, our success and willingness to share information has brought out a number of short lived LLC’s that were run by rip off artists, and mentally ill people. Particularly, there have been four businesses that made poor copies of our parts or untested garbage. All of these are bankrupt today. Because they were LLC’s they could take peoples money without any liability to repay it. Today, I have just heard that another is coming back with a new name. The story will never end as long as people don’t do their home work or believe that they are getting a bargain. You can read about one of these companies at this link: Cloudn’t have happened to a nicer guy……
I warn people all the time not to buy things from these people, or to buy this stuff at the flymart. For examples of things no one should have bought, look at this story: Built by William Wynne? Built according to The Manual?
Let me be absolutely clear, that I will be polite to people, but I will not work on, offer advice on, or help with products made by bankrupt people that I considered vermin. If you have one of the engines from these LLC’s you are out of luck. I will not allow you to join our ‘Zenvair’ group nor will I allow you to attend any of the Colleges. This isn’t out of spite, it is to protect these builders lives. They all want to put a band aid on their bad purchase and make it “good enough to fly.” A band aid isn’t going to do it, an amputation is in order. People who blew $12K on Junk don’t want to hear this, they are still looking for a cheap out that doesn’t exist. I will not assist them in the delusion that they have found one.
The Zenith Builders and flyers website has a small number of old posts from people who bought trash like this for their projects. If you look closely, these people offered great testimonials, but later abandoned their builds. On the same sites, I have builders like Larry Winger and Rich Whittington sharing that the same people took their money and delivered trash. Some people still don’t do their home work.
Below is a photo of a heavily damaged Zenith 750 with a Corvair in it. At first glace you might think it was the work of one of our builders, but it is not. The photo was sent to me by the insurance agent who wanted to know who much it would cost to repair. I told him I wouldn’t touch it for any price.
The problem with the plane is that the owner bought from the wrong people, and later wanted a ‘band aid’ fix, and tried to alter his engine to look more like the ones we teach people to build. Looks don’t count, function does. This plane had a rear starter that deleted the harmonic balancer. This required a goofy motor mount to clar the ring gear in the back. After the builder had a number of failures with the original starter, the builder bought another crank from another LLC in Georgia and tried to set up the plane with front starter parts bought second hand. On one of the first flights after the band aid was applied, the entire prop hub assembly and the prop came off the plane in flight and it crashed. The reason for this was probably something as simple as having the wrong flange on the replacement crank. The owner didn’t tell the insurance company that he had applied the band aid, but they found out anyway, and when they did they started talking about voiding the coverage. All of this could have been avoided by doing some homework before the original purchase, or just starting over when he realized his mistake. This is why I don’t help people put band aids on things that need to be amputated.
Just one thing to look at: The two down tubes in the mount that support the cabin structure. Note that they are actually broken. Look closely and see that they had a direction change and a butt weld right in the middle of the tube to clear the original rear starter set up. That is pure trash put out by people with no education and purchased by people looking for a bargain. I am not here to serve such people. I believe that people have a human right to end their lives, but this doesn’t require me to assist them in doing so.
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Corvair vs O-200…. weight comparison
Builders,
A Zenith 701 builder that I spoke with at the open house wrote me a short note asking some questions about the weight comparison between these two engines. This is something I have directly compared, something we have very good data on, and some valid and useful commentary.
For people with short attention spans, I will cut to the chase and say that a modern Corvair, as we teach people to build them, with electric start and a charging system, weighs the same installed as a standard O-200 Continental. You can see in the photo below that I have weighed, thrust tested and dyno run them side by side personally. Many people will comment on the subject of engine output and weight on power plants they have never laid a hand on, far less run on a dyno. Most of the “evidence” people present is well intentioned, but erroneous just the same. Bad data, presented with good intentions or malicious ones, is still bad data. The numbers here come from personal measurement, intentionally done in public for people to see.
“More Lies are told in experimental aviation than in singles bars” is a saying I made up 15 years ago to illustrate the loose association with truth that many people in our field have. The most common fib told in home building is under quoting how much something weighs. (This is ironic, because compared to numbers like HP output, true stall peed, or ultimate G strength, the weight of anything is a very simple matter to check, but very few people ever do.) Many people I quick to point the finger at salesmen, but let me also say that I have done the weight and balance on something like 100 homebuilt aircraft, and only found 10% of the owners were remotely telling the truth on their W&B sheet. Many of these people told their buddies their plane was exactly 100 pounds lighter than is was. Frequently they repeated it often enough that they forgot they made it up, and could have passed a polygraph test swearing to it. Take this away: Don’t believe anything you hear about weights unless you are listening to the guy who did it himself, who has photo documentation of him doing it. If you would like to read a funny story about how reality has a hard time competing with fantasy, take a moment to read this link:
Unicorns vs Ponies.
On the left above is the Continental O-200 as removed from a 1959 Cessna 150. This engine is considered the standard against which all other 100hp class engines are measured. It is a direct drive 4-stroke, 4-cylinder engine of 200cid. It carries a horsepower rating of 100 at 2,750rpm. I have read that Continental produced about 50,000 O-200s. On the right is a 170cid Corvair engine. For size comparison, the O-200 is 32″ wide without the baffling. The Corvair is 28″ wide.
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The caption in italics above is actually nine years old from our main page flycorvair.com. It is from a long test series on dyno and thrust testing the O-200. You can read the full story at this link: http://www.flycorvair.com/thrust.html . The picture above shows that a Corvair is smaller physically than an O-200. Let me also offer that I know a bit about Continentals and I like them. Graces Taylorcraft has an STC’ed C-85-12 in it, an engine that is nearly Identical to an O-200 in physical size and weight. Keep in mind that when people compare engine weights on the net, very few of these people have owned both of the engines they are commenting on, and in many cases, the guy offering the data has owned neither. It doesn’t make then bad nor evil, it just means their data on this subject probably isn’t good.
What about the often quoted 188 pound weight for an O-200? That is erroneous, as it does not include the starter, mags, plugs, carb, oil, or many other items it takes to run the engine. The data was actually presented that way so if a manufacturer chose Eisman mags instead of Bendix, he could do a weight and balance engineering solution on the engine. The 188 number was never meant to be a comparison all up weight.
What about the new light weight O-200? Yes, it is lighter than a traditional model, by as much as 20 pounds. But this engine, which Continental rep. Kim Winner brought to the Zenith open house, sells for $20,000. It is new, and they have made very few of them, and you are not likey to come across one for sale used for another 20 years. Many of the parts in it can not be used on older engines. Most builders are taking about a Corvair they could build on a $8500 budget vs a traditional O-200 taken from a Cessna 150 for roughly the same money. If you want to spend $20K, I can build you a Corvair that is far lighter than the lightest O-200 ever made. Given $8,000 or $10,000 just to spend on weight reduction, much could be accomplished, but that isn’t an engine most people are considering, and neither is the new light weight O-200.
Is an O-200 ‘Approved’ for a 701 but not a Corvair? You can call Zenith and speak with Roger or Sebastien, and I am sure that they would advise any 701 builder to first consider lighter engines. But they would also tell you that both engines have powered 701s before. We bought our 701 test bed kit directly from the factory in 2005 and completed it in 2007. Sebastien sold it to us to test the concept after seeing the success of our 601/Corvair program. The 701 worked. we made no attempt to lighten the Corvair for it, and the plane weighed 677 pounds ready to fly. (if that didn’t sound very light compared to other numbers you have read on the net, go back and read Unicorns vs Ponies again.) It did not need any ballast whatsoever to get into the CG envelope. On this last point, the Corvair has a distinct advantage over the O-200; The Corvair is ‘flat’ on the back, and can be pulled right back to the firewall without creating a maintenance issue. An O-200 has the mags and wires sticking out the back, and they require several more inches of clearance to be removed without the requirement of pulling the engine off the mount. Although the Corvair and the O-200 effectively weigh the same, you can’t get the O-200’s CG nearly as close to the firewall. It may require ballast just to get into the front of the CG range.
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Above, Our test bed Corvair powered 701 in the Zenith booth at Sun n Fun 2010.
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I have heard that a heavy engine can break the 701 nose gear, truth? Yes, a very heavy engine could be a factor, but when we built our 701 I studied this closely, and a far bigger issue was people flying the plane forward of the published CG envelope. One guy had tried a Geo engine with a belt drive on a 701. This was actually lighter than a Corvair, but the engine layout was very long, and it had to be positioned well forward to clear items from the firewall end of the engine. The result was I guy flying around 2″ ahead of the forward CG limit. The plane could be landed smoothly by rolling it on at 60 mph, but that wasn’t the point of the 701. When the Geo guy tried landing slow and pitched the nose up, he found out that planes that are ahead of the forward CG limit drop their nose like a rock at high angle of attack. This is the effect that harms the plane. It is actually a CG issue, not a weight driven one. Poor pilot technique is another big factor. Any guy willing to get a little time in type training and fly within the published CG range has little to worry about.
What about reasonable cost Corvair modifications to reduce weight? A 3,000 cc Corvair actually weigh 7 pounds less than standard ones becase the bigger engine uses a lighter aftermarket cylinder set. A billet crank is nearly 4 pounds lighter than a stock one. A welded pan is a pound lighter than a billet one., etc. There is a list of parts than can get 15 pounds off a Corvair, but most builders find the engine to be acceptably light in the basic form. People frequently ask about putting aluminum cylinders on Corvairs. I have been working with Corvairs for 25 years, people have been talking about these for at least 12 years, and yet no one has ever taken a set flying. I have good reason to doubt the would work. If some one tries to talk you into anything that has never flown, and the national expert doubts will work, realize they want you to be a guinea pig. They sell down at the pet store for $20, and if your life is worth more than that, don’t be anyone’s Guinea pig.
Last Comment of weights: Two people in the alternative engine game, myself and Robert Helms, president of UL power, never hesitate to tell the truth about how much our respective engines weigh. Robert has nothing to loose by doing so; He has the lightest engine on the market, he doesn’t need to embellish the facts. In my case I don’t have anything to gain by under reporting the weight of a Corvair. People choose the Corvair because it is affordable, smooth, a learning experience, well supported, made in America and a multitude of other reasons. It has the features above, while having an acceptable level of weight for a broad variety of aircraft. If I fibbed about the weight of the engine I wouldn’t attract any significant amount of new builders, but it would undermine the trust and rapport with builders we already have in place.-ww.
Steve Williamson Pietenpol at 60 hrs., SoCal.
Builders,
We had previously featured Steve Williamson’s Piet in this story:
New Pietenpol, EAA #1279, French Valley CA
Steve mailed us the update letter and photos below:
“Hi William,
Just to update you on our Chapter 1279 Pietenpol, we have more than 60 hours on the airplane since its first flight on January 5 of this year. The Corvair engine is performing flawlessly (after some early glitches you already know about).
We were unable to make the West Coast Pietenpol fly-in at Hollister in June due to a death in my family. But we did put the airplane on display for the first time last weekend at the Flying Circus event at Flabob Airport in Riverside. I must say it looked right at home among the beautiful examples of antique airplanes and it attracted a lot of attention from the crowd of admirers. We had a local paint shop do a color match of the blue Poly Fiber paint on the fuselage and create a high gloss paint for the aluminum cowling. That, along with the powder coated “Air Camper” valve covers really made the airplane stand out. (See photos below)
Thank you for all the support and encouragement you gave us in the building of our Corvair engine.
All the best,
Steve Williamson President EAA 1279, French Valley CA.”
SPA Panther will be at CC#27, Nov. 8-10, Barnwell SC.
Builders:
Dan and Rachel Weseman, well known to Corvair builders, have confirmed that they are bringing the Panther and their family to CC#27. While thousands of people have seen the Panther in person on display at Sun N Fun and Oshkosh, and have the extensive films of the plane flying aerobatics on their site and you tube, I will assure you that there is nothing like seeing this plane in action, in person, right from the side of the runway. Builders attending Barnwell will be afforded this, as well as a chance to examine the plane closely, and ask Dan questions in a far more focused and productive setting than Oshkosh. Airventure is fun, but it can not hold a candle to a college when it comes to learning in depth information.
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They will also be at the College in their traditional role supporting Corvair engine building. They offer the new Billet Cranks #1001B, as well as the full processing on GM 8409 cranks, The group #2950 rear alternator and the #3000 Weseman bearings. Contact Rachel for more availability information on these items, especially if you are heading to the College.
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We have several Panther builders already signed up for CC#27 who are coming to work on the Corvairs that will power their Panthers. These guys are planning on being there for the full event and getting the most out of it. In addition to these builders, Rachel has arranged with PF Beck, our local host, to have potential Panther builders stop by and get a look at the plane in person when it is in their neighborhood. To my mind, these same people will be able to a look at a first class Corvair College in action, and we have a very good chance of welcoming them aboard as fellow Corvair builders at the next College. If you know someone interested in getting a look at the Panther encourage them to check out this link to The panther page:
http://flypanther.net/
For Builders who would like to read more on the plane, the main page is:
http://flywithspa.com/panther.html
Above, Paul Dye, Editor in Chief of Kitplanes magazine, made the pilgrimage to Florida for a test fight in the Panther. He was totally impressed. He gave the plane a full check out, which will appear in a future issue of his magazine. Grace and I also had a chance to spend some time with him, and I found him to be a real homebuilder, and a surprisingly knowledgeable guy on many facets of our branch of aviation, very interested in getting to meet homebuilders in the field . He had nothing but positive things to say about his first experience flying behind a Corvair.
Having Paul Dye as the Editor of Kitplanes is very encouraging in an era where the Editor of EAA publications is more interested in the multi-million dollar French TBM-850 turboprop than any new homebuilt. Like most homebuilders, I have traditionally found the EAA’s publications as my primary source of printed information. Thirty minutes with an editor who came across the country to personally fly a real homebuilt design with an affordable engine was all it took for me to understand that we are far more likely to find our kind of information in Kitplanes these days.-ww.
Zenith 601/650 Motor mounts, P/N 4201(A)
Builders:
It’s 3 am here and we are still up, just part of the fun of prepping for Oshkosh. This is the time of night when you take a break from answering email, wander over to the refrigerator and stare inside. The dilemma: Is it too late to drink beer or is it too early to drink coffee? Answer: both, but I have just enough brain cells still working to write a web update on motor mounts…….
In two weeks we will be at Oshkosh. There will be many people there offering motor mounts for sale for every kind of plane. Polo shirt clad salesmen will make loud claims about how great the mounts they are selling are. They will hit all the welding buzz words they have heard, and they will sound knowledgeable to people who know nothing about welding. The vast majority of these salesmen have never even tried welding, and they couldn’t put down an airworthy bead an inch long even if their life depended on it.
That last sentence is a typical WW, 3 am, overstatement isn’t it? Jeez, when is some Oshkosh salesmen’s life going to depend on his ability to demonstrate a skill he talks about but doesn’t posses? Reality Check: The salesman’s life doesn’t depend on the welding he is promoting and selling…….only yours does.
Grace has redone our Zenith 601/650 catalog page on these mounts, which are part number 4201(A) in the new numbering system. If you were thinking about getting one of these from us, review the new information. We have seven of these mounts on the back porch ready for the powder coater. In a few days I am going to take them in and have them done for sale at Oshkosh. If you would like one, would like to save the shipping and have a particular finish in mind, follow the link, place an order, or feel free to send us a note or call. We will be glad to cover anything you would like.
http://www.flycorvair.com/601mount.html
Below, a photo of Vern and I outside my hangar 18 months ago. We will both be at Oshkosh. 100% of all the welded products we sell are done by the two of us. At the show, ask us any question on welding you like, we only have 74 years of personal, first hand, welding experience between us. We can probably cover it better than the polo shirt clad salesmen. If you got into experimental aviation just to buy stuff, then any salesman will do just fine for you. If you got into experimental aviation to learn, develop your own skills and craftsmanship and make things with your own hands, then who you work with really matters. You can’t become and old school homebuilder / motor head by buying things from salesmen. They have nothing to teach you. While I will be very glad to sell you a motor mount, I am very glad to share all the detailed information on how it was made, and the materials and processes. Yes, I sell things, but first and foremost, I am a homebuilder with a mission to share what we have learned.
From our website in 2011: “For the greater part of his years on earth, Vern has been a welder. In the world of experimental aircraft, when a company wants to sound impressive, they always tout that their welders have “Built race cars.” I welded the frames of lots of NHRA legal dragsters before I was 21, and this experience taught me nothing about aerospace welding. Vern has welded countless race cars together, but that has nothing to do with why we utilize his skills making Corvair parts. What counts is the little piece of paper on the orange board.”
“If you look closely, it shows that Vern has every aerospace material welding rating in every thickness recognized by his employer, the United States Naval Aviation Depot. In this facility inside NAS Jacksonville, Vern has welded every kind of material that goes into modern combat aircraft. This includes titanium, Hastelloy X and magnesium. While some people can weld this when it is new in a purged box, Vern can weld things like the inside of a jet’s burner can while looking through one bleed hole and feeding the rod through another.”
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Below is a photo of Woody Harris’s 601XL, and an important story about his experience. Woody is “Our man on the West Coast”, based in Northern California at Vacaville. Note that his plane is pictured in North Carolina. I welded the engine mount that is on his plane. It was done in the same fixture that we used to make the ones resting on the back porch, 10 feet from where I am typing this.
From our website in 2010: “In the above photo, Woody Harris’ 2,850cc Zenith 601B sits at the end of the ramp in North Carolina at First Flight Airport with the Wright Brothers Monument in the background. This brings his aircraft to the end of his first leg of a coast-to-coast and return flight. I believe that this is a pretty classy way for Dad to show up at his daughter’s house on the East Coast. Although Woody has spent a lifetime in the mechanical world predominantly driving race cars in both Europe and America, it’s worth noting that he’s been in aviation less than five years. While he certainly would have thought of it before, it was at the urging of his daughter who is an ATP, that he explore some adventures in flying. I mention this because if you’re out there reading this and you’re thinking that you might be too late in the game to have your own adventures, you’re quite wrong. If you don’t have a pilots license, you have never built an airplane before, and you’re 63 years old, you are at the exact spot where Woody was four years ago. Yes his mechanical background gave him a leg up, but it plays a smaller role than most people suspect. His determined character and his quest to learn new things were much bigger factors in his favor. If you had been standing next to me at Oshkosh when Woody arrived, and watched him hop out of the airplane and talk for 4 minutes straight about the previous days flying, including sentences like “We timed it perfectly because Old Faithful went off just as we flew by,” you would note that all the hours that you’re putting in your shop are well worth the adventures that lie in your future. Go out there tonight and get one evening closer to writing the same chapter in your own story that Woody has written in his. (I have Woody looking into his logbooks, but I am pretty sure he has flown a Corvair powered plane in more states than any other person. I don’t bring this up as a point of competition, I just want builders at home to understand that with good judgment and training, you can go a long way, even if you have not yet written in the 500th hour in your logbook.)
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Randy Bush’s Pietenpol hits 500 hours.
Builders,
An email arrived last night from Randy Bush, saying that he just crossed over the 500 hour mark on his Pietenpol. If you are new to homebuilding you probably understand that this is a significant milestone, but if you have been around homebuilding for a long time, you really understand how big this is.
Getting started, we all believe that we will fly about 250 hours a year in our creation, right after it is done in 10-12 months. Dreams are made of these thoughts, and that is good, but flying planes are made of dreams and persistence. I am going to say that less than one in ten homebuilts of all kinds gets to 500 hours. This includes all weather cross country planes like RV’s. Combine this with the fact 80% of kits and 90% of plans are never completed, then you begining to see Rany’s accomplishment in perspective.
If the odds above don’t sound good, you are correct. But success in homebuilding isn’t a random a random lottery ticket drawing, it is a series of good decisions, bonded together with persistence. If you know and exercise this, the odds don’t apply to you. The reason why I spend a lot of time speaking of philosophy, is because it is the root of all good decision making in homebuilding. People who have never spent 5 minutes considering the “why?” element, and developing their own answer to this question, have a low success rate because they are not making good decisions, nor developing their own persistence.
Last week, I was speaking with well-known Pietenpol builder and Cherry Grove trophy holder Kevin Purtee. Randy’s name came up, and Kevin paused the conversation to make the point, “That guy is a first class human being.” I feel the same way. When people like to complain that the EAA doesn’t have enough old-school home builders anymore, I agree, but Randy Bush is always my first example to point out that we still have some that are every bit as good as they ever were.
Randy is going to fly his Pietenpol to Brodhead this year, and go on to Oshkosh with it also. He has just reworked his cowling and made some detail changes, like the ones in this story: Cooling with J-3 style cowls. (Pietenpols, Cubs, Biplanes, etc) and he now reports that even at full power on a hot day, his plane will only hit 325 degrees on the cht. (that is 250 below GM’s red line). This is running on the border of being too cool, an issue that some Corvairs can have, but very few other alternative engines ever have to be concerned about, as they are concerned with melt downs. I plan on getting a number of photos of his plane at the shows, and we can have a whole story about his mechanical installation, but to my view this is secondary to the real story, namely Randy getting to 500 hours because of the choices he has made and the persistence he has exercised.
Going to Brodhead or Oshkosh will be an excellent chance for many people new to homebuilding to meet Randy in person. You will find him to be a modest and humble guy. I have long held that negativity is an infectious disease, and you should not spend your aviation hours in the company of people who have it. Conversely, I believe that the perspectives, examples and mindset of successful builders like Randy Bush are also contagious, and spending even an hour in their company can make a big difference in the positive path of any homebuilder. Below I share a few stories that I have written about in the past that give a glimpse of why Kevin Purtee, myself and countless others hold Randy in very high regard. Come, met him in person and add yourself to this group.
Above Randy at Brodhead 2012, From last years story: “Randy Bush offers his testimonial on Corvairs and Piets in combination. He now has more than 420 hours on his plane. This is a lot for an open cockpit aircraft based in Tennessee. Many Corvair people met Randy at previous Colleges. Both he and I have had many conversations about how homebuilding and developing and exercising your craftsmanship in aircraft building is a refuge of sanity and stability in our personal lives. We have both noted that when many people hit a rough patch in life, one of the first things they think of doing is quitting their aircraft project. Either of us, and everyone else who has finished an aircraft under challenging circumstances, would gladly offer that selling your project is the last thing you should do. When little else is going right, and few people are on your side, hours spent in your shop will show you that you still control much of your life, and the opinions of you held by others are often worthless. In your own shop, your are in charge, and any hour spent building something with your own hands is well spent and the things you learn can never be taken from you. Go back and read the Sterling Hayden quote about what men really need to lead meaningful lives.”
Above,Randy’s aircraft at Brodhead . “Randy Bush of TN. at Brodhead with Miss Le’Bec (it is a combination of his girls’ names). His aircraft was seven years in the making. A consistent work of craftsmanship, the plane’s creation spanned both easy and hard years in Randy’s life. Many people new to homebuilding think that it is something you do if life is treating you great and you’re rolling in dough. Here is reality: The most successful builders I know understand that hours spent in your own shop, creating things with your own hands, is a vital part of a worthwhile life, and that this reality will be most evident at the hardest of times. Learning to make things is a crucial investment in your own sanity. Does it surprise anyone that really happy people always have a way of being creative? The plane has more than 400 hours on it. It has a 100 hp Corvair with electric start and a Roy 5th bearing
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I wrote the words below last year. If you are a homebuilder that has spent a lot of hours reading this site and thinking about the potential of homebuilding in your life, let me share this single prime element of homebuilding, the part of it many homebuilders find to be the most rewarding and crucial element of it. Magazines and websites all want to tell you that homebuilding is about buying things and having stuff. That is a pathetically shallow perspective, and is at the root of why people quit when the have great expenditure but feel no personal reward. If you really want to get to the core of homebuilding, then start looking at its potential to change your own life, that it is a serious arena where you can develop and test your skills in a setting that matters, that you control, and has rewards that few other challenges can match.
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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.
I was aware of this in my youth, but it did not come into focus until 1999, the worst year of my life. (getting burned was 2001, but it was a picnic compared to ’99.) Feeling dangerously low, I sought the council of a guy I knew. He had come back from such a year. He is an artist, working as an incredibly detailed wood carver. He tells me to forget everyone and everything else, go back to your tools and work with your hands. Give up your apartment, but never your hangar. Explore all the things you can’t forget, have stolen, give away or loose. At the moment, I was having a hard time picturing another week, and I asked him how long it took him. The thought with great care a slowly said “two, no really three..” I was jolted and blurted out “Three months?” he looked me in the eye and said “No. Years. It’s probably your only way out.” It turned out to be a painfully accurate prediction.
In the years since I have read letters or posts from many people in a tough spot, who have sold their project or tools. I often think their ship is sinking and they have just traded their life jacket for five more minutes on the deck. I have also met a number of successful builders who have said that when everything else in there lives was broken, they had a place of refuge in work and creation. Of the thousands of people I have met in aviation, these people are truly brothers, for we share the same salvation.”
Zenith 750 Flying on Corvair Power, Gary Burdett, Illinois
Builders;
A week ago we put up a story about Gary Burdett’s 750, but at the time we didn’t have a photo of the plane. The original story is at this link:
Gary Burdett, 2,850cc Zenith 750, now flying. (engine selection)
Since then Gary has put a number of flights on the plane, and has nothing but good things to say about the combination. He took a moment to send us a picture of the plane, (below). A very sharp, straight forward, good-looking bird. Again, Hats off to Gary for a job well done.-ww
Flying Zenith 750, Tom Siminski, 2700cc, PA.
Builders;
I have been meaning to post a longer story about Tom Siminski’s flying 750, but for now here is a quick glance at a 750 that has been flying since last year.
Above, Tom’s completed bird. A very sharp-looking plane. It has a 2700cc engine with a Dan bearing and all of our installation components. Tom is flying the plane out of Eastern PA. I first met Tom at CC#14 in Lowell Mass, four years ago. Looking back at the event, many of the people who were there, like Louis Leung and Rodger Pritchard and Tom are now flying. Since then we have held 10 more Colleges, and I have spoken with countless builders along the way. However, two sentences that Tom said as an observation on that day have stuck with me as if he said it 3 minutes ago. I like building engines, working with tools and making parts, but it is working with the builders that is the rewarding part of my work. After a couple of hundred engines, they all begin to look alike, but their builders all remain unique individuals, each with his own perspectives, motivations and observations.
Hats off to Tom Siminski, builder of a flying Zenith 750.-ww.
From our website about Corvair College #14 in 2009: “With me above is Thomas Siminski, a highly skilled machinist of the Old School variety. He had some very helpful suggestions about prepping threaded holes that he shared with builders. When I got a chance to speak with him one-on-one later, he impressed me with his broad personal experience from a candid perspective.”
Flying Zenith 750 w/3000cc Corvair, Doug Stevenson, California
Builders,
Below is a picture of Doug Stevenson’s Zenith 750. It did it’s first flight two years ago, it was the first Zenith 750 to fly on Corvair power. Doug keeps the aircraft at French Valley, in the scenic desert area of inland Southern California.
Doug’s plane is powered by a 3,000 cc Corvair with a Roy bearing. The engine was a joint project done by Roy and myself, completed and test run as a demonstration at Corvair College #18 in Northern California. A few days after the College, I drove down to the other end of the state and delived the engine to Doug, one of hundreds of in-person house calls I have done over the years.
At CC#18, we focused on builders engines, and as a consequence, It took one extra day to take our time on Doug’s engine. It was a memorable Sunday evening of wrenching, a chance to reflect with Roy about all the things builders had accomplished. Roy and I finished the engine and prepped it for an early run on Monday, seen above. It fired up after 2 seconds of cranking and ran flawlessly throughout the early break-in period, It was a nice wrap up for the College #18
