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


We are 30 hours away from leaving for Oshkosh. Dan and Rachel Weseman are also heading up, and we will both be at booth 615 in the North Aircraft Display area, between Zenith and Vans. The Wesemans are bringing The Panther prototype airframe to display all the progress they have made in the few short months since Sun N Fun. Because they are good friends and we wanted to do something to support their new effort, I offered to assemble the 3,000cc Corvair that will power Panther #1. Here are a few photos of the completed engine. It will also be on display at the booth.

Above, the engine is a 3,000 cc engine with a Weseman bearing, Falcon heads and all of our Gold System Parts. The engine features some of the latest developments and a unique fuel system. The pictures of this engine are a good visual complement to our previous post on 2012 Engines For Sale. Other than the intake and the injector, this engine is the same as the ones that we assemble for builders. This engine is also an excellent blueprint for anyone building their own engine from our parts. The valve covers are one of our powdercoated sets with welded on oil filler and breather lines.

Above, a rear view of the engine. Behind the harmonic balancer is an alternator driven off the crank through a flexible coupler. It is a joint project that Dan and I have been working on. It retains the balancer and cannot put bending loads on the crank. I have never been a fan of belts on the back of the engine, but this system does not use one. The alternator is the same Yanmar unit we traditional use on the front of the engine. The set up will be flight tested after Oshkosh.

The intake is a custom stainless part made in our fixture so that it mates with our traditional welded on head pipes. On the bottom of the intake is the Precision mechanical fuel injection unit. Dan has designed the Panther to have tremendous airframe strength. The test wing took more than 9Gs at gross weight in a sandbag test conducted after Sun N Fun. Although Dan designed the plane to be easy to fly, it will be capable of impressive aerobatics. With the intention of ultimately being able to fly it with inverted systems, Dan has selected the Precision injector as his fuel delivery system.

Here is a good frontal view of the Corvair. It is only 28″ wide. This is 4″ narrower than an O-200, 6″ narrower than an O-235 and several inches narrower than a VW. The Corvair is a tough compact package. Six cylinder engines will always end up as a smaller package than a four-cylinder one of the same displacement. This view shows our new simplified adjustable starter motor bracket that eliminates the previous link arrangement. The single oil line runs direct from the Gold Oil Filter Housing to Dan’s bearing. Braided stainless hose and full flow AN hose ends look and work great but are not as expensive as people think. This hose was easily assembled from $36 in parts.

Of course Dan’s plane is going to use one of his bearings.  Originally a heat-treated casting that matched the finish of the Corvair’s cast case, the Wesemans switched to CNC machining the same design out of solid billets of aluminum. As part of their commitment to keeping aviation affordable, they did not raise the price when making this improvement. It goes without saying that this unit is entirely made in the U.S. out of U.S. material. With well over 200 of these bearings in the field, it is by far the most popular bearing. It has three strong cards to play: It is by far the lowest cost bearing, it is retofitable in the field to existing engines, and it is readily available, as the Wesemans now have them machined in large groups to have them on the shelf.

The photo is also another good look at the simplified starter arrangement. We have four-part kits for engines with Weseman bearings that consist of the new starter ear, two machined aluminum spacers and a pre-made tail bracket that allow any of our starters with a bolt on ear to be adjustably mounted on an engine in 15 minutes without fabrication or drilling. We will have these sets at Oshkosh.

Looking at the above photos and thinking about the Corvair’s well deserved reputation for strength and cool operation, it is easy to understand much of the popularity of the engine. I have been working to develop the Corvair flight engine continuously since 1989. The engine has matured tremendously during this time, but it has never lost it basic simplicity in the 52 years it has been an experimental aircraft powerplant. While others may be captured by engines sold as “new and exciting,” the Corvair remains a very popular option for builders looking for “Old and Proven.” 

I have said many times that the Corvair isn’t for everyone. We sell assembled engine just like the one above for roughly half the price of a Rotax 912, but there are plenty of people who pathologically purchase imported mechanical items. We can teach people to build a Corvair just like the one above for less than $8,000 in parts, but learning things and getting their hands dirty are alien concepts to many people who claim to love experimental aviation. For the rest of us, the Corvair is a great opportunity to have a proven and affordable powerplant.-ww

2012 Corvair Engines For Sale: 100, 110 and 120 HP


Over the years, we’ve built more than 100 high quality production engines for builders who opted to buy the finished product from us. Some of the best known flying Corvair engines were built in our shop. As a policy, every one of these engines are test run and broken in on our dynomometer/run stand. A review of our and Web sites will show photos of dozens of engines we’ve built that are now flying. Our great experience with Corvairs, our use of only the highest quality parts and the test runs have given us a 100% track record with production engines. This record makes it easy to stand behind engines we’ve built. By and large, people who have selected our engines, installed them on their aircraft and operated them as we recommend have had to do no work other than regular oil changes and spark plug replacement at 200 hour intervals.

Many people who have selected a production engine still opt to attend the Colleges to get to know the inside of their Corvair engine. I absolutely encourage this because education has always been our primary work, and an educated Corvair pilot will not only have greater knowledge and confidence in his equipment, but will also offer valuable testimony to builders just considering the Corvair. 

We have three different displacements/HP ratings available. Below we have three examples, one of each engine we have assembled, test run and delivered this year. If you have further questions about your application, feel free to write or call.

All of the engines we build are completely overhauled and modified with state of the art components made in the USA. Every engine has a forged crank that has been Magnafluxed, stress relieved, ground, balanced, nitrided, polished and balanced. Our engines are built on the readily available Weseman 5th bearing. We have built a number of other engines using our own bearing and the one from Roy’s, and we will gladly speak with anyone about using either of these bearings. We use the Weseman bearing as our standard offering because it is well proven on more than 100 engines and it is economical.  Our bearing and Roy’s add $1,000 to the price of an engine.

The heads we use on our engines come from Mark at I have been working with him for almost 10 years. His background as a Spartan-trained A&P mechanic, and a 32-year history of working with Corvairs led him to being the number one man in the world on cylinder heads for Corvair flight engines. He has worked directly with us over many years to fine tune every detail of head rebuilding and precision machining defines what state of the art is. Many of the successful flying Corvair powered planes today are utilizing his heads. Over the years he has produced more than 150 pairs of heads, and they enjoy a perfect track record.

Additionally, all of the engines have forged pistons, and the 2,850 and 3,000 have new cylinders. (The 2700 cylinders are re-bored GM originals.) They have forged rods with ARP bolts, harmonic balancers and high volume oil pumps. Each engine has dual ignition and electric start with a 22 amp alternator. The engines have our gold oil system and the builder’s choice of billet or welded oil pan. (Heavy duty oil cooling systems are a popular $600 option.) The only major component not included is the carburetor. While any of the engines can be used on airframes as different as a KR-2S to a Zenith 750, the carb must be a good match for the airframe. For example, aircraft with low wings and fuel pumps require MA-3 or Ellison carbs, while gravity feed airframes can use a wide array of carbs, including the affordable Stromberg. The Corvair has flown on more than 15 different carbs, and we will be glad to assist you in choosing the correct one for your airframe.

Above, an engine we assembled for a builder at the beginning of 2012.  The engine is on our run stand outside our hangar. Every engine we assemble is test run and broken in on our run stand. The engine’s performance is carefully evaluated against dozens of others we have built. This test run allows even fine details such as the hot idle regulated oil pressure to be preset before the engine is delivered.

Above, a picture of a 3,000 cc dished “Dual Fuel” forged piston. These are made in the USA to our exact specification. These pistons are the heart of 2,850 and 3,000 cc Corvair engines. They allow these engines to run equally well on 100LL or high grade automotive fuel. The design maintains a very tight quench area to the head while keeping a moderate static compression ratio. Many alternative engines have electronic elements and valve designs that are not compatible with the high levels of lead in aircraft fuel. Others have excessive compression ratios that make operation on fuel below 100 octane a serious detonation risk.  No such issues exist with our Corvair conversions. When Corvairs were built, all automotive fuel was leaded; in the past 30 years they have proven to operate on unleaded fuel. Our 2,850 and 3,000 cc engines have these special pistons to maintain the ability of operating on either fuel. Corvair engines are not bothered by ethanol in fuel. The head in the picture was remanufactured by Mark at Falcon Machine.

Above, a look inside an engine during assembly in our hangar. As a direct drive, horizontally opposed, air cooled engine fed with a single carb, the Corvair engine is a model of simplicity and reliability. It has been powering experimental aircraft since 1960, and we have been continuously working with them since 1989. Many people new to homebuilding are taught by magazines to look at things which are “new and exciting.” All of my work in the past 23 years has been aimed at testing and developing proven methods and systems that builders can count on. “Old And Flight Proven” is the opposite end of the spectrum. It is my personal philosophy that many more homebuilders have been served by “Old And Proven.” Builders who understand this fundamental truth of aviation naturally gravitate to our work with the Corvair.

 Below are three example of assembled engines we offer:

2,700 cc Engine, Weseman 5th bearing, 100hp continuous, 225 pounds, $9,750

Above, Zenith 650 builder Becky Shipman and myself observe a break in run of her 2,700 cc engine at Corvair College #22 in Texas. This engine was assembled in my hangar before the event. Attending the event gave Becky a good look at what was inside her powerplant, and familiarized her with the operational procedures. We encourage builders purchasing an assembled engine from us to attend Colleges we offer. Read the whole story on Becky’s engine at the March link

2,850 cc Engine, Weseman 5th bearing, 100hp continuous, 225 pounds, $10,750

Above, Roger Grable and his grandson Graham stand by their new 2,850 cc engine during its break-in run at Corvair College #23 in Florida. I assembled the engine in our hangar before the event. Roger and his wife had attened CC#22 four months earlier, and had elected to have us build an engine for his fast moving project. We have a fairly short lead time on complete engines, and Roger drove to CC#23 and took delivery on the engine. There is an Internet based rumor that claims that we do not build engines or they take a long time to get. The three real world examples of engines we have built this year offer a reality check on such stories. To read the complete story on Roger’s Zenith 750 engine, follow this link to Corvair College on in June

3,000 cc Engine, Weseman 5th bearing, 120hp continuous, 218 pounds, $11,750

Above, a 3,000 cc engine we built for the Zenith 750 project of Lary Hatfield and sons. We met Lary at the Zenith open house at the factory, which he followed up by attending Corvair College #21.  In person, Lary is an easygoing guy with a laid back approach on the surface. When you learn more about his experience, you understand that he and his sons have worked very hard and had outstanding success in very competitive levels of automotive racing. They are equally accomplished in aviation. They have worked hard enough to afford to put any piston engine they choose on the front of their Zenith, yet they selected a Corvair after careful consideration. I take it as a compliment to our work with the Corvair when men of their mechanical experience carefully evaluate and choose Corvair power. A longer story on their project can be found at:

A long time ago, I realized that a builder buying an engine from us was really purchasing more than a powerplant. He is making an investment in our judgement. Builders are looking for a good value in an engine, not the cheapest price. Airplanes are a lot of fun, but airworthiness is serious business. I appreciate this and cut no corners on engines that we build.

The single most important thing a builder can understand about our engine program is very simple, but often overlooked. Completed engines are a small portion of our efforts with the Corvair. Most of our work goes into teaching builders how to build their own engine and supplying the conversion and installation components. Carefully and correctly built engines actually are not a particularly lucrative part of our operation. We build them for several reasons beyond the bottom line: They are excellent demonstrators of the potential of the Corvair as we convert it; They provide a blueprint for builders assembling their own engines; and we often use them as assembly or test run demonstrators at Colleges. To serve the above purposes, they must be carefully built of the finest parts. Moral issues aside, there is absolutely no incentive in any form for me to cut any corner on any engine. A single issue in the field would undo the larger purpose of building the engines in the first place. We have been here for a long time, and every time I turn a wrench in the shop I am aware that I will be doing this in another 20 years also. There is no short cut to long term success.

Conversely, any company that makes its living just on complete engines, especially if it is an LLC, has an enormous incentive to cut corners on every part inside their engines. The only way they make money is by charging more, lowering their cost, or both. In tight economic times, price has a ceiling, so lowering the cost and cutting a few corners is the way to go. They can do the math, and every dollar they will ever make is based solely on this differential. They know that 9 out of 10 engines they sell will not go flying in the next 3 years. Organized as an LLC, they can walk away from the business without any financial obligation to their customers. If you’re new to aviation this may sound far fetched, but it is actually how the majority of alternative engine companies have been started, operated and dissolved in the past 20 years.

Our income is not based on the finite possibilities of the cost versus price equation. Our potential is directly related to the reputation that the Corvair enjoys as an affordable and reliable powerplant. The engines we assemble for builders enhance this reputation by being excellent examples of the conversion. Even the most cynical person who is yet to know my personal morality against poor products in experimental aviation can understand how we are only incentivized to build excellent engines.

If you are a builder interested in discussing an assembled Corvair for your project, let me suggest the following; take the time to read the stories in the links above. Also get a look at our main reference page, At the bottom of the main page is a search box that allows you to find any subject. The site has well over 1,000 pages of text. You don’t have to read it all (some of it is historical or dated), but you will find an excellent introduction to the engine. Then, write me with any questions you may have. Please include your phone number, and a good time to call you. We keep all the information confidential, but I find the phone a much faster way to cover builders’ questions. Understand that we get many emails every week asking about buying an engine. Some are scams, others are from 15-year-olds, some are from people asking if the engine will power a Lancair IVP, others asking what type of antifreeze goes in the engine. There may be one real builder in the group. In my experience, the real builder appreciates 30 minutes on the phone, and all the others want to have long protracted email exchanges. Set yourself apart, send your phone number.

As all of our engines are hand-built, I’ll be glad to discuss individual custom touches for builders ordering engines. A confirmed engine order requires a 50% deposit, and the balance must be paid before the engine is shipped. Crating and shipping are a modest, but additional cost. You can place your engine order with a check payable to William Wynne, 5000-18 US HWY 17 #247, Orange Park, FL 32003, or by credit card via PayPal to

Corvair College #23, 2700cc Engine, Spencer Gould, SP-500

In the above photo, from left to right, Spencer Gould, Dan Weseman and Mark “Petz” from Falcon Machine at work on Spencer’s engine at Corvair College #23. Dan is covering the installation of his 5th bearing onto Spencer’s engine. Originally built as a plain 4 bearing engine, Spencer elected to add Dan’s bearing, a fairly easy upgrade that does not require the engine to be disassembled. Dan’s presentation on how to do the process complemented the clear directions that come with his bearing.

Above is the same process from a different angle. Here the prop end of the engine with the Safety Shaft is sticking straight up. Installation is easier on the bench, and it is easiest if the pistons and rods are not yet installed, but Dan has demonstrated many times that the upgrade to his bearing can be done without ever removing the engine from the airframe. He now has well over 200 bearings in the field, and they have been proven over 5 years of service. Upgrading an engine requires a shorter hub to keep the same length of Studs, Shaft and cowling. The Wesemans offer this machine service to builders who already have one of our Black Hubs or a Standard length Gold Hub. Builders that are planning on using a Dan bearing from the start order a Short Gold Hub from us.

Above, is a good look at the clean lines of an engine equipped with a Front Starter and alternator. Note that the engine has just one oil line on it, running from the Gold Housing to a Weseman Bearing. In its final installation, the engine will have a Gold Sandwich between the Filter Housing and the filter, and two short lines feeding a large cooler mounted on the engine baffling. This is another view of our new Starter Bracket. The outboard side of the triangular bracket is slotted allowing the adjustment of the starter engagement. This eliminates the previous system that had a drilled link plate. Spencer’s engine has the oil fill in the top cover because it is going on his single seat design, and he is planning on a form fitted cowling that would come too close to the right hand valve cover to have room for our standard oil fill location. The left hand valve cover has our standard crankcase vent line and oil return. The engine uses our Short Gold Hub because it has a 5th bearing. The bearing is one of the Weseman’s original cast housings, before they went to billet CNC production.

Another view of the engine. The welded on intakes were welded on the heads by Mark Petz at Falcon Machine. Like most flying Corvairs, Spencer’s engine has one of our E/P Distributors. Oil filter is a K&N 1008, the plugs are AC-R44Fs, my first choice for both of these. The dip stick is an aftermarket one for a 289-302 Ford, with the tube shortened 5″. The engine hardly needs more than a set of ignition wires and a baffle set to be installed on an airframe. None of the engine systems need to be mounted on the firewall: The engine is largely a self-contained, neat package. The engine will be flown with a HD oil cooler because the airframe is designed for strong maneuvers and solid acrobatic work, and excess oil cooing makes sense on a plane that will be flown at full power and slow climb speeds. On the run stand, engines can be operated without oil coolers because the oil comes up to temp very slowly with the engine uncowled.

Above, Spencer’s engine at power on the stand. Note the size of the cooling baffle we use on any engine we are running on the ground. We recently had a builder extensively damage the engine he built by running it on the ground without any type of cooling baffle or cowling.  In every photo we have of running engines at the Colleges, especially brand new ones being broken in, they have a generous amount of cooling air being pumped through them by the baffle. Prop wash over an uncowled engine does not work, period. Without a cowl or a cooling baffle box, none of the air has any reason to flow down through the cooling fins on the head. How long does it take to hurt the engine? How much running is OK? Answer the question for yourself this way: If you just spent $5,000 and a lot of time to rebuild the V-8 in your classic muscle car, how long would you run it without a radiator?

Actually this isn’t a fair comparison. A v-8 in neutral turning 2,000 rpm is only making 10 or 15 hp, it is not pulling any load. It has a several hundred pound mass and lots of oil to heat up. Conversely, a Corvair with a flight prop turning 2,000 rpm has to be at half throttle and may be making as many as 60 horses. It doesn’t have the mass to heat soak either. You could run the V-8 longer without damage.

Keep in mind, if you hurt your newly overhauled v-8, it may leave you by the side of road later. If your flight engine is wounded by cooking it during break in, it may choose to get even with you later, and it is much more likely to do so on a full power climb out than it is idling on the ground. In the end, what exactly was to be gained by running the engine on the ground without cooling? Building a box too much work? Few scraps of sheet metal cost too much? Building the most elaborate cooling box will never take 10% of the time nor 5% of the cost of rebuilding your engine. The longest time I ever run an engine without a cowl or cooling box (once it is fully broken in) is 45-60 seconds, and only 5-10 seconds of this are much above idle. I would do this while setting the timing on an engine after maintenance. On many of our cowling designs like the Zenith cowls, you can just pull the top hinge pin on the passenger side and remove the top access panel. The cooling system will stay in place with the exception of a 4″ square hole. You will have full access to work with the Distributor and set the timing. Our cowling design took factors like this into consideration, and that is why it makes a lot more sense than trying to scab together a cowl from leftovers of some other engine.

Above, Spencer enjoys the finest form of air-conditioning on the planet, prop blast from an aircraft engine created by your own hands. A close look at the exhaust on the run stand shows that I have oxygen sensors on both sides to run an air/fuel meter (lean-rich gauge).  Initially, I liked the idea, and a number of well-known Corvair pilots like this instrumentation as well. Here is the turn off for me: The sensor works on a tiny signal difference, and it is very prone to any type of grounding issue. This is a pain, but not too hard to overcome. My real objection it that when the device loses its signal, its default position is reading perfectly in the green arc. I find the very concept annoying. Would you use an oil pressure gauge that indicated 45 pounds every time the wire was disconnected? How about a fuel gauge that always read 1/3 full when it was having an issue? To me, I want instrumentation that when it fails, it clearly indicates that it is dead, it doesn’t provide misleading info. There is probably some electrical reason why the air-fuel meter reads green when it is dead that makes sense to an engineer at a computer, but if I put it in a plane, it has to make operational sense to me. Lest you think I am making a mountain out of a molehill, than consider that the airliner hitting the 14th street bridge in D.C. was primarily caused by an instrument error on the EPR gauge; the airliner that went into the Everglades 30 years ago had the crew fixated on a failed instrument light; there are enough stories about professionals being undone by faulty instrument data that homebuilders should consider this issue with attention. In my personal opinion, almost any Corvair engine can be well served by 2 simple EGT probes in the exhaust. EGT systems are stupid reliable, and when they are disconnected they don’t read.

Above four of the major contributors to the modern Corvair movement: From left, Mark from, Dan Weseman from, myself, and Spencer Gould.

Today, Spencer’s day job is aeronautical engineering for the world’s greatest aircraft powerplant company, Pratt-Whitney. Contrary to the popular image of serious engineers being challenged by practicality, Spencer is a multi-faceted renaissance man of aviation. He is a very skilled pilot of complex aircraft, he is the master of CAD drawing and machining, he can fly any RC aircraft with skill, he has designed and flown dozens of them. He designed and has built 98% of his own composite acrobatic aircraft, the SP-500, and has a broad array of practical knowledge in the world of aviation. If you need a technical solution to a structures issue, a finite element analysis, or a process, Spencer always has valid input. In the years between his graduation from Embry-Riddle Aeronautical University and Pratt, he worked as a powerplants engineer for Piper in Vero Beach.  During that time, Spencer was an adjunct member of  The Hangar Gang, and covered a lot of our CAD work. Designs that I had for the Gold Oil System, the modern Hubs and our 5th bearing were refined by Spencer’s CAD ability, and they went directly to CNC production from code we e-mailed to the machine shop. He was and remains a very important force multiplier in our efforts, an asset that few other engine programs could claim to match.

If you are new to homebuilding, stop and think about this: The Corvair not only has appeal to people whose day job is far from aviation, but it also has great appeal to builders like Spencer who are immersed in aviation, men who understand all the issues involved in powerplants. Spencer could afford any piston engine he wanted for the front of his aircraft. Yet he selects the Corvair because after careful evaluation, it all adds up to the right choice for him. The engine isn’t for everyone, but no builder new to aviation need worry that the engine isn’t capable of meeting the demands of educated professionals and amateurs alike.-ww

Corvair College #23 – 2850cc Engine, Roger Grable, CH-750 Builder


Here is another builder’s story from Corvair College #23. Below is a sequence of photos of the 2850 cc 110hp engine we assembled for Zenith 750 builder Roger Grable from Missouri.  All of the action pictured took place at the College.  

We met with Roger and his wife Sarah at CC#22 in Texas a few months ago.  It didn’t take long to understand that he knew engines fairly well, and had considerable experience working on them. His questions were observant and thoughtful. He spent #22 carefully considering a plan that made sense for his project and timetable. By the end of #22, Roger made the decision that he wanted to have us assemble a 2850 for him, and this would keep his fast paced 750 project moving.  I have no problem building an engine for a guy with Roger’s approach. He still wanted to learn as much as possible, and that in my book is what makes him a good Corvair guy.



Above, Roger and I stand beside his engine on the run stand.  Every engine we run has the oil system primed for 20 minutes with an electric drill. The only oil we use for break in is Shell Rotella T 15w-40. In every engine we add ZDDP. You can get it from a lot of places, but Clark’s sends it with camshafts they sell. We run the engine for 25 or 30 minutes without stopping, at 1500-2000 rpm. This has proven over hundreds of engines to protect the cam and lifters, which are the primary thing you are concerned with during the first hour.


Above, a number of the builders at CC #23 admire the smooth power of Roger’s 2850. The engine is equipped with a billet Weseman bearing and a very nice set of Falcon heads. We configured the engine for a heavy-duty oil cooler. On aircraft like Zenith 750s, the slow climb speed capability and the high angle of attack challenge the stock oil cooler capacity in hot weather. Thus, we set the engine up with a cooler block off plate and a Gold Sandwich Adapter and a 20003 series aircraft oil cooler. The baffle kits the Wesemans offer are fitted for either the stock cooler or the 20002 or 20003 series. When complete, the oil system is contained on the engine, none of it is mounted on the firewall or cowling. This gives the engine installation a clean, organized appearance.


Above, Roger keeps an eye on the oil pressure. His engine is equipped with our new high volume pump. For these, I carefully  use the mill and expand the capacity of the oil pressure bypass, to prevent the engine from having a very high peak oil pressure on start up with cold oil.  When the engine is first started, several minutes of operation to warm the oil is a good idea, and we do this at 1000-1200 rpm.  In a few minutes the oil will regulate at 50 psi or so. When the engine is at full temp, this will settle down to 45 pounds of pressure. This slight reduction in regulated oil pressure between 140 and 205 degree oil is a Corvair characteristic. Beside Roger in the yellow shirt is his grandson Graham of Kansas. The young man proved to be very smart and good company. Many of the builders though Graham was 20 or 22 years old by his manner; it was a small surprise that he is far younger, still in high school. He is very interested in flying, and it is easy to guess that he will do very well. The kind of younger person who defies all the common media stories about youth.

We often get inquires about complete engines. Most of these are from people who only know about the low price of the engine. They have no other attraction, they know almost nothing of our development or support. Experience has taught me that any guy who decides to buy an engine he never heard of before after reading a one paragraph news release is not a guy who is in things for the long haul. Any guy who thinks you’re a genius in 1 minute is just as likely to decide you’re a fool without reason. Steady people who consider merits thoughtfully are typically the people who succeed in homebuilding. To understand an extreme case of people who are only interested in price shopping, I had a guy ask about a 3,000cc engine. He said it was priced at $50 more than his other choice, a four-cylinder, geared, tiny displacement computer controlled, imported car engine. I pointed out that philosophically these were radically different concepts in aircraft engines, and he needed to think his choice over a bit.

His response was to ask if I would sell him an engine but not the Conversion, Installation and Operations manuals, so it would reduce his cost and make up his mind. I calmly asked him why I would sell an engine to anyone who told me they didn’t want any instruction on how to operate it. I hope he is happy with the other engine, I don’t work with people who know the cost of everything but the value of nothing. Roger and his family impressed me as the perfect antithesis of such people. We have room in the Corvair movement for many types of people, but I can make a good argument that experimental aviation and flying in general has had quite enough of people who have no interest in learning anything.


Above, Roger and his grandson Graham. The picture provokes a thousand thoughts on where their adventure will lead. Will they both be there for the first flight? Will his grandson solo in the plane? Will Grandfather be the first passenger in his log book?  I watched the two of them at the College, they were having a very good time together. Roger, obviously proud of his grandson, and the young man accompanying his grandfather on an important and fun trip. Both of my grandfathers passed before I was born. Looking at these two made me think about it many times during the College. I have been very lucky in many ways, but as a young man I would have treasured having a grandfather. In person it was easy to tell that Roger’s grandson felt the same way about Roger.-ww



Corvair College #23, 2700cc Engine, Ray Fuenzalida, KR-2S Builder


It has been a few weeks since Corvair College #23 here in Florida. I have a few stories to write up and share from the event. We have been busy heading into Oshkosh, which is now only a month away. We have ended up with a little free time because of tropical storm Debby. It has been raining cats and dogs over the past three days, but it is expected to peak tonight, where we can end up with another 4″ of rain on top of the 12″ we already got. As a precaution on flooding, we have shut down the hangar for a day and picked up everything near the floor and turned off the power. This involved picking up the TIG welder with the engine hoist and putting the planes up on ramps. It is a lot of prep work, but it prevents damage and we will be back in action the day after the storm passes. For now, it provides time in the house to write up a story from CC #23.

Above, Corvair/KR builder Ray Fuenzalida from New Orleans. Ray has attended three other Colleges, but he decided to make #23 the special one and finish and test run his engine there. His basic engine is a 2700 with a Weseman 5th bearing. It will be more than enough power for an outstanding KR installation. Over the years Ray had considered several different starter/alternator configurations, but after seeing a lot of finished engines run at previous Colleges, Ray moved to using our standard front starter/front alternator configuration, primarily because he liked the simplicity of it. In the photo we are admiring the diamond plate top cover Ray made. We said something about a guy in Lake Charles, Louisiana, with one running board on his 1970s Dodge conversion van being ticked off…..

Above, Ray’s engine was about 1/2 complete when he brought it to the College, but we took the time to go over the engine with a fine tooth comb. One of the things we changed was his rear oil case. Ray’s core had come with an oil case from a 1960-61 Corvair. They fit, but they are a heavy sand casting. We replaced it with a die-cast one that had been fitted with one of our high volume pumps. The pump is a good idea with a 5th bearing. Standing with Ray is Dean Smith, long time Corvair movement guy, also from Louisiana.

My talented and  beautiful wife Grace painted the sign above. We have few rules at the Colleges, but we always abide by them. We lay off the top two subjects of conversation (as they rarely bring people together) and the third is that we teach builders to avoid products from totalitarian police states noted for poor quality. Ray has been a really good sport while we tease him about bringing a torque wrench made in the Peoples Republic of China. Over the years, I have shown many people that these are not accurate enough to build an aircraft engine with. Particularly offensive to me is the brand name “Pittsburgh.” I was born in the actual Pittsburgh in 1962. We bring a highly accurate Snap On digital torque wrench to every event so builders don’t have to worry about this if they are assembling at the College.  For those working at home, I suggest a Craftsman beam type wrench in 3/8 drive. They are good and cheap.

Above is a good overall view of Ray’s engine. Note the top cover has been replaced with our standard one, it is part of the Front Starter package. Ray painted it to match his engine. The diamond plate one was too thick and not smooth enough to mount the Front Starter Brackets. Ray also picked up our last non-anodized front Alternator Bracket. The only thing about Ray’s engine that is slightly different from our production 2700 engine is his use of bolt on head pipes. We used them for a long time, but every engine we have built in the past nine years had used welded on intake pipes. There is a slight flow increase with welded on pipes, but I particularly like eliminating the gasket. Our Intake Manifolds can be made to work with bolt on pipes, but they are really designed to work with welded on pipes. Mark at Falcon has a set of fixtures to do the job that are set to perfectly match our manifolds. Guys with personal skill at welding aluminum have purchased the manifold and used it in reverse to locate the head pipes without a fixture. If you do use bolt on pipes, do not use the gasket for a Corvair carb, instead use Clark’s part number C-12A, which is the gasket for the turbo intake on the car.

Ray’s engine has a very clean look because it has only one external oil line, a -6 line right from the Gold Oil Housing to the Weseman bearing. His oil cooler is a stock GM unit. These have long proven to work on small, fast Corvair powered planes like KRs and Cleanexes. All of Dan Weseman’s hard-core 3100cc powered Wicked Cleanex flying was done on a stock 12-plate cooler. The faster the plane, the smaller the oil cooler required.

Another look at Ray’s engine. Engines built with 5th bearings use the Short Gold Hub. For the past several years, we have used a sold Ring Gear in place of the 2003-07 model we used that had spokes. (It was an FRA-235 Pioneer, no longer in production.) The new model is from a late-model Ford. We buy them in the unmachined state from NAPA and individually machine each one on our lathe. This is a good view of our new Front Starter Bracket, which eliminates the drilled link of our previous starters. This new bracket comes standard on the starter we sell. We also have pre-made tail brackets for starters going on engines with Weseman bearings. The Fram 6607 filter shown is just for ground runs; we use a K&N 1008 in flight. Again, look at how clean the configuration is; it needs hardly more than plug wires and baffling to be installed. Ray’s engine will not need anything like the filter, cooler nor bypass mounted on the firewall. All of these are on the engine itself, which makes for a very organized engine compartment.

Above is the moment that counts: Ray’s engine at power on the run stand. Here is a proud hour where the learning and the effort has paid off. Ray got to share this in the company of his fellow builders. In his home EAA Chapter, he may not have a single other guy who has ever built a flight engine. At the College, this is the common ground, everyone is there to learn. At times, it can be hard to find other aviators who understand the desire to build and fly your own airframe and engine. Here is where the Corvair movement really shines, as it is made up entirely of self-reliant individuals who prefer to get the full measure of creativity and pride from homebuilding. People not content to go through the motions of the consumer experience of buying an imported engine in a box. The Corvair movement is for individuals who have willfully chosen to see how much they can learn, create and master in aviation, not how little. If this sounds like your mindset, welcome aboard. Hats off to Ray Fuenzalida, an individual who has earned the title Corvair engine builder.-ww

2,700cc-Skycoupe-2002 Photos


Below are a set of photographs that I took 10 years ago. It’s a Stits SA-7D Skycoupe that was owned at the time by Gary Coppen. In the Winter of 2002 I was just getting back in action after losing our Pietenpol. Gary showed up with an engineless Skycoupe and offered to leave it with us on long-term loan. He understood that we needed a new testbed and demonstrator, and he offered his proven airframe without cost or strings attached.

We set to work immediately and went about producing a modern Corvair engine installation. The photographs you see here are from the Spring of 2002. While some of the things look antiquated here, it’s worth noting that the layout of Front Starter and Front Alternator that we continue today is used on this aircraft. Our Pietenpol had used both front and rear starters and alternators over the years when we used that airframe as a testbed. By the time I got the Skycoupe, my ideas on installations that would serve the most builders were already sorted out. Simplicity would remain the overriding goal. Although we have continuously done research and testing, the Skycoupe in the 2002 update to our Conversion Manual marked a turning point in our work. Previous to this, our Conversion Manual was really my shop notebook filled with useful information for people working on their own conversion. The Skycoupe in the new Manual was different. The engine installation was meant to be something that builders could replicate and expect proven success from. The Manual had become more of a how-to document, giving a lot of information on building and installations like the Skycoupe, in addition to the previous material on operations and practices.

In 2003 we purchased our 601 XL kit from Zenith at Oshkosh. We had the aircraft complete and on display in the Zenith booth at Sun ‘N Fun in April of 2004. Our new Zenith rapidly eclipsed the Skycoupe as the focal point of mainline testing and demonstration. The Skycoupe was seen less often but still lived in our hangar for a number of years. In 2005, we took it to Sun ‘N Fun and put it on display as our flying Turbo testbed aircraft.  It served in this capacity for a long time before it was damaged in a windstorm. Several years ago, we started a restoration but it was sidelined by more pressing projects. 18 months ago, Gary reluctantly put the Skycoupe up for sale. He owns a number of other aircraft, including Corvair powered KR-2S, and he didn’t want the Skycoupe to wait a number of years until he had more time. 

Today the Skycoupe belongs to Craig Anderson of South Dakota. The airframe is undergoing a much needed total restoration. Craig is headed off to Corvair College 22, now only 10 days away. There he is going to assemble and test run the new powerplant for the Skycoupe. It is a 2,850cc engine with a Weseman bearing, Falcon heads, and all of our Gold system parts. Although this engine is state-of-the-art it does directly have its lineage in the Skycoupe’s 2002 installation. The starter and the alternator are in the same orientation, as are the cooling and electrical systems. The 2,850 will have 10 more horsepower than the 2,700 engine in the photographs. With its dished pistons, the 2,850 will run interchangeably without adjustment on both 100 low lead and 93 unleaded. In the photographs, the Skycoupe was equipped with one of our then state-of-the-art Dual Points Distributors. Craig’s engine will run with our modern variant, the Electronic/Points Distributor. Overall, his engine is a series of incremental improvements, carefully thought out over a decade’s worth of work. Less than one out of 10 experimental aircraft companies survive to see their 10th birthday. We had already had 10 birthdays by the time I took the photographs you see here. We are in this for the long run, to support builders as they work towards their goals. If you have dreams and plans that involve building and flying, and they have remained important to you for a long time, then make this your year of action.  The decision is up to you, no one else can make it for you, don’t let it pass you by.

Here is an overhead view of the Skycoupe’s engine installation. The Starter is the same one we use today but on a different set of Brackets. The alternator is a permanent magnet, but an early 14 amp model. The oil system is virtually stock with a 12-plate cooler and stock oil filter.

Here, a rear three-quarter view. In the foreground is an aluminum box that houses the coils, the MSD coil switcher, and the voltage regulator. They were placed here because the Skycoupe has a 20 gallon gas tank immediately behind the firewall. The 1.5 inch scat hose feeds cooling air to this box (the box had internal baffles that restricted the airflow to less than the hose size suggests), the air flows out the bottom after flowing over all the components inside. The Distributor is a Dual Points model. The oil pressure sending unit worked in this location but the temperature always read incorrectly.

Here, the Oil Pan shown here is the first Deep Sump Welded Aluminum Pan that we made. We still offer these today. I used this same motor mount layout to build several other later mounts in the shop. It also appears on Dave’s Wagabond in 2004, our Buttercup project in 2008, and on our Tailwind project in 2011. The carburetor is a Stromberg. The large hose is feeding fresh air from the cowl, the small is for carb heat. The gascolator is at the lowest point in the fuel system.

Here, on the valve cover is a Cessna 150 breather. These worked under most circumstances, but proved to be very difficult for builders to get inexpensively. With the 601, we moved to the readily available Aircraft Spruce breather. The location, however, was a winner; we have put every set of breather lines at this location since. The exhaust system is ceramic coated mild steel. These do not last compared to stainless models. The tubing size here is 1 3/8″. Testing proved that it needed to be slightly larger. The overall exhaust system layout remains fairly close to this. The goal is minimizing the amount of surface area under the cowling.

This photo shows the passenger side view.  The Skycoupe was the last aircraft we built that had a bolted on intake at the head. We abandoned this when we moved to our new Nosebowl shape with the Zenith 601. If you look closely, you can see that this intake manifold is made out of many separate pieces of of mild steel. A painstaking project of gas welding. Today the intake manifolds we offer are the same shape, but are made out of a single piece of stainless tubing. This also offers a good view of the side of the cooling box. The main battery cable and the starter cable meet each other on a phenolic plate on the side of the box. Internally, they are connected to the voltage regulator. The wiring bundles are packaged in red Fiberglas woven tubing for chafe protection. The front of the baffling looks blunt because this aircraft had previously been flown on a Subaru with a belt reduction. That engine had an extremely flat face, and the baffling seen here only filled up the original cowl. In later testing, the Skycoupe was converted to one of our Nosebowls which transformed it from an ugly duckling into a guided missile.

Above: One of the last tests I performed was blocking up the aircraft to a 22° angle and chaining the tail down. We actually ran it in this position for extensive tests of its fuel flow at full power, and checking that the Deep Sump Oil Pan would feed oil at this angle at wide open throttle. The system worked very well. In 2002 I sported Burt Rutan mutton chops. Grace isn’t nostalgic about them today. These photographs were taken in front of our old hangars at the Spruce Creek airport in Daytona Beach, Florida. The hangars were built in the 1960s and were among the oldest structures at the airport. By 2002, Spruce Creek had evolved into the world’s largest fly in community, a gated location of 1,200 hangar homes.There were many good people there. Our hangars, nicknamed “the ghetto” by the real estate agents, were the focal point of lively after hours beer drinking and hangar flying. Most of the aviators in attendance were successful guys with million-dollar homes and hangars with painted floors where nothing interesting was happening. Our hangars reminded them of good times in their past when things were simpler and fun was a lot more accessible. In 2003, NASCAR driver and spruce Creek resident Mark Martin bought our whole hangar row and had it torn down and replaced with four expensive hangars that ended up housing golf carts and Prevost motor homes. The lasting important lessons that I took away from the experience was never to envy wealthy guys in aviation, a lot of them have lost touch with the most fun elements that drew them into flying in the first place, and to make sure we retained the element of good times amongst friends in everything that we did.

3,000cc Engine Running


Below is a freshly built 3,000cc Corvair running in front of our hangar. We built it for Zenith CH-750 builder Lary Hatfield. Grace and I met Lary and his sons at the 2011 Zenith Open House in Mexico, Missouri. The Hatfields were taking the Zenith Builders Workshop and picking up their airframe kit. They got a good look at all the engine options for the aircraft, considered carefully and selected the Corvair. Lary acknowledged that each of the engine options for the 750 had some appeal, but our knowledge of the engine, our 23 years in the business, the number of Zeniths flying on the Corvair, and the fundamental simplicity of our approach made the decision for him. 

The economic appeal of the engine that attracts many people was not a factor. Lary speaks with a lot of fatherly pride about his sons’ hard work ethics and their personal successes. Although he never mentioned it, I am guessing that Lary could afford any engine on the market. Lary and his sons have a very strong aviation background. When men of this experience and means study the options closely and select the Corvair, I take it as a compliment to our efforts.  When we first started, the Corvair was seen as a low cost alternative for people economically excluded from hand-me-down certified engines. After two decades of development, testing, flying and teaching, the Corvair has now evolved to a top tier engine, a first choice powerplant.

Above: The engine during its first break in run. We operate it between 1,800 and 2,200 rpm for 30 minutes. The primary purpose is to break in the cam and lifters. We only use Shell Rotella 15W-40 oil for this, and we use an additive called ZDDP. We do the break in with slightly conservative timing, and run the engine on 93 unleaded fuel to avoid having lead deposits in the engine if it is going to be stored for a while before it is flown. In the presence of moisture, the byproducts of combustion from 100LL fuel can be corrosive over time. You can see that the run stand is chained down to an 800 pound concrete block we cast into the lawn next to the ramp. The only thing visible on the block is a 1/2″-20 threaded bolt hole. It is actually the balancer end of a scrap Corvair crank that we cast into the block.  It’s not likely to be uprooted any time soon.

Above is a look inside the 3,000cc Engine. It is a big brother to the 2,850. The centerpiece of both of these engines is a drop forged, CNC machined, made in America, very high quality piston manufactured to our specifications. It has a very specifically designed pocket, and a flat quench area, for use with the 110 and 95 Corvair cylinder heads. The step that the head gasket sits on can be entirely machined out of the head so that the quench height of the engine is solely the head gasket thickness. This could be done before, but would result in an alarmingly high compression ratio. The pocket in the piston takes care of this, keeping the compression ratio reasonable. Other pistons for Corvairs have had little dishes cut in them before. But we had these pistons specifically forged with thick domes to allow the pocket to be machined as deep as it needed to be without compromising the strength of the piston. In operation, this engine has extremely high turbulence and very good atomization of the fuel, yet a static compression ratio that will easily run on 93 octane fuel without retarded timing. These combustion and ignition characteristics have the potential to make this engine more powerful than a 3,100cc Corvair with its required retarded ignition timing. There’s a number of other reasons we selected 3 Liters as our new standard large displacement engine, but the primary goal was to produce an uncompromised large displacement Corvair that will operate in a future where the affordability of 100 low lead may come into question. The 2,850 has the same characteristics, but it is the largest displacement that can be made without machining the case.

Above:The 3,000cc engine makes 120 continuous HP at 3,150 rpm. The engine has no difficulty making this power output and remaining cool while doing it. In this photo, the engine is running on the same MA3-SPA carb that we test all of our engines on. This is the most popular carb for CH-750s. Next, we will test this engine with a Precision mechanical fuel injector. It is expensive, but it is made by the same people who produce injectors for certified aircraft. We run the engines with cast iron manifolds and small mufflers to get it quiet so we can listen to the engine internally during the break in. This engine performed flawlessly. Grace’s  1946 Taylorcraft sits on the lawn behind the engine.

The engine above is built with a Modex-prepped forged and nitrided crankshaft. It has a Weseman 5th bearing, as well as a brand new valve train including the cam drive gears, lifters and pushrods. The forged pistons and cylinders are new and the rods are Clark’s rebuilt with ARP rod bolts. The heads have new seats and guides and stainless valves set with exhaust rotators and new springs. The engine has one of our new high volume oil pumps and a Dale harmonic balancer. It features all of our Gold Oil System parts,including the Billet Pan and Deep Sump Pickup, our Short Gold Hub and Front Starter System, a 20 amp charging system and our redundant Electronic and Point (E/P) Ignition System with spiral wound ignition wires. Because it varies from airframe to airframe, the carburetor is sold separately. We build these engines for $11,500. A dedicated builder working in his shop can build a clone of this engine for $7,500 in parts and about 150 hours of his time. (Smaller displacement engines like the 110hp 2,850cc and the 100 hp 2,700cc can be built on significantly tighter budgets.) We are glad to work with both groups of people. With other engines, the engine is always configured in the way that is easiest for the factory to make, or the most profitable set up. Your Corvair engine can be built in any way that suits your airframe, budget, timeline or personal goals.

Our main focus is, and will always remain, teaching builders how to build their own engines. This is the approach of 95% of the people we are working with. We are the only engine company on the market dedicated to giving people who wish to build it themselves access to a top-level engine.  We build a small number of engines a year. These are done as educational showpieces that effectively demonstrate the potential of the engine. With this purpose, the engines we build are assembled out of the finest materials and parts. I personally assemble each of them, and I take as many hours as needed to do so. Afterward, each of them are given a long break-in run process, and then a final tuning. These engines only serve their purpose if they provide long trouble-free service to their owners, in the process demonstrating to observers how well the Corvair works. Again, 95% of these observers will choose to build their own engine with our parts and assistance.  In plain terms, this means that our motivation when building an engine for a family like the Hatfields is to produce the finest engine, not the most profitable one.

Contrast this with traditional automotive conversion engines.  Those engines were sold as the sole profit-maker by companies whose overriding goal was to make money. Many of these engines were based on things pulled directly from cars, cleaned and declared airworthy. Companies that did rebuild engines were tempted to cut every corner inside, because that’s how they were going to make more money. Most of these companies were LLCs with 3 year life spans. They knew that if they sold 100 engines in the 36 months, 90 of the engines would not be mounted on an airframe.  Their high time customer engine would likely get less than 100 hours. If that guy had issues, they could keep him quiet by sending him an “updated” engine or offering him some money back. By the time the majority of  buyers discover that there are issues, the LLC has folded up the tent, and they don’t have to stand behind anything. This isn’t a bad dream, nor is it far-fetched. When I got started in 1989, there were 40 or 45 nationally known alternative engine companies. Today, just 3 of these remain, and the only other one that still goes to Sun ‘N Fun and Oshkosh is Steve Bennett at Great Plains VWs.  There were 15 companies offering EA-81 Subarus, all gone now. Zoche Diesel never turned out a product. The Cam 100 Honda, and almost all the other Honda people, are gone. A half dozen outfits that offered small turbines and delivered nothing are gone. So are most of the V-6 people, and all the V-8 outfits I can think of except one. These companies were designed and run to make money, not to last. When they disappeared, they took a lot of people’s money and dreams with them.

Corvairs have seen their share of these people. In the past 5 years their have been four LLCs that sprang up to make Corvair parts. All four are bankrupt today. All of them were previously customers of ours. Naming them doesn’t matter as much as understanding that there will certainly be new ones over time.  While I feel some sympathy for people who were taken by these LLCs, it isn’t my obligation to help out the people stuck with orphan products, and this includes not having them at our Colleges. Everyone understands that your local Ford dealership isn’t going to work on a 1986 Yugo. It’s the same thing here.  I include this as a reminder to builders that most of the people who start an aircraft project don’t finish it. Our builder completion rate is about 35% after four years. This is twice the industry average. There are a lot of reasons why the industry is so low. They are incentivized to sell you things, not teach you things. The journalists writing about planes generally haven’t completed a plane, and 95% of them have never gotten their hands dirty on an aircraft engine. There are countless Web sites with disinformation provided by people you will never meet. Reading them allows these people to affect your perspective and reduces the probability of your success. These factors are never going to get better, and in all likelihood are going to get worse. The good news is that you can exercise good decision making skills, pick the right people to listen to and learn from, work with proven companies and navigate your way through. Last year, nearly 1,000 new amateur built aircraft were completed and registered with the FAA. If your personal goal is to learn, build and fly, we will be glad to work with you to get your name on the next list.