Over the years, we’ve built more than 100 high quality production engines for builders who opted to buy the finished product from us. As a policy, every one of these engines are test run and broken in on our run stand. A review of our FlyCorvair.com and FlyCorvair.net 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 spotless track record with production engines. This record makes it easy to stand behind engines we’ve built. These engines are fully remanufactured, and converted for aircraft duty. 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. The TBO on the engines is 1,500 hrs.
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 encourage this because education has always been our primary work, and an educated Corvair pilot will be a better owner and operator.
All of the engines we build are completely overhauled and modified with state of the art components made in the USA. Our engines are built on the readily available Weseman 5th bearing. There are other options like a Weseman billet crank, which adds about $1,500 to the cost of an engine. We are glad to include any proven option on your engine.
The engines can be used on airframes as different as a KR-2S to a Zenith 750, so 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. 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 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. 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 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:
2,700 cc Engine, Weseman 5th bearing, 100hp continuous.
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 our Colleges. Read the whole story on Becky’s engine at this link: Shipman Engine at CC#22
2,850 cc Engine, Weseman 5th bearing, 110hp continuous.
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. This engine is now flying in their Zenith. 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. To read the complete story on Roger’s Zenith 750 engine, follow this link: Corvair College #23 – 2850cc Engine, Roger Grable, CH-750 Builder
3,000 cc Engine, Weseman 5th bearing, 120hp continuous.
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 on http://www.FlyCorvair.net 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, FlyCorvair.com. 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.
Here are some notes about our oldest ignition system, the Dual Points distributor. I made the first of these models nearly 20 years ago. We went on to produce several hundred of them. In the last seven years there have been superseded by our E/P and E/P-X distributors, which themselves are evolutions on this basic design.
Dual Points distributors served the Corvair flight community very well. Many thousands of hours have been flown on these ignitions, and there has never been a single forced landing nor accident attributable to the design. (we have had people fail one side because of pinching a wire putting the cap on, but they flew on the other side) The design uses two sets of points from a Corvair mounted 180 degrees apart. either one can run the whole engine smoothly.
We mount the condensers remotely on the coils. When I introduced this, there was a giant debate on the internet claiming the condensers being on the end of 20 inches of wire would case some sort of ‘delay’ in the ignition, even though I pointed out that electrons travel down wires pretty much at the speed of light, and 20 inches vs 186,000 miles per second is a very short interval, the debate lasted years. Meanwhile, many happy people went out and flew countless enjoyable hours without noticing.
In the 1960s, companies like Mallory made dual point distributors for racing Corvairs, but these had three lobes not six, the goal being much shallower ramps on the point cam that would allow 7,500 rpm operation. such a distributor can not provide redundant ignition.
Today, we sell only a handful of D/P distributors a year. They are a special order item, but the remain popular with some very old school builders and some builders Down Under. They work well, but I highly encourage all builders to use E/P series distributors instead, they run smoother and have comparatively little maintenance. (D/P points need cleaning or replacing every now and then, but on the E/P the points are a back up and pass no current normally and may go 1,000 hrs. of operation without adjustment.) All the engines we build and sell are equipped with E/P series ignitions. Read all the articles and decide which system you like, they are all well flight proven.-ww.
In the above 2006 photo, a Dual Points distributor P/N 3301(D/P). The screwdriver points to one of the two 8/32″ screws that hold down the Points Plate. Two things I tell builders relentlessly, but are sometimes not heeded: 1) Never adjust the points to make the gap .019″, the gap on all distributors come from us pre set to a specific dwell, not a gap, and if you let anyone talk you into jamming an old feeler gage in the points, you will upset the pre adjusted timing. I have had 40 or 50 people do this and then rationalize it by saying “the gap looked small.” If people want to do this, I will fix it, but it does tell me who reads directions and who wants to argue rather than learn and understand. 2) Never take the two plate screws loose for a look inside, it will have the same effect as doing #1. Builders can replace points on these in the field, but it is done by matching the existing preset gap on the original points, not by using some book value.
The above photo shows a Dual Point Distributor in the machine. If you look closely at the 11:00 o’clock position you can see the illuminated arrow pointing at the degree wheel. the distributor machine was made in 1950. The items piggybacked on the top row allow the simultaneous operation of the electronic side of the Distributor while superimposing the EI picture on the scope. Every single distributor we ever send out the door is test run in this machine.
When running a Distributor on the machine, I can vary the rpm it’s turning and observe its advance directly. When your Corvair engine is idling, the advance weights in the Distributor are held shut by springs. The advance at this point is referred to as the static timing. I set the Distributors so they have little advance below 900 rpm. As the engine comes off idle, the mechanical advance inside the Distributor’s body makes the spark occur earlier. This is the mechanical advance at work. All the mechanical advance needs to be in by 2,400 rpm or so. This way, you can tie the tail of your airplane down, run it to full power and check what the total advance is at the propeller’s full static rpm. Total advance for engines running on 93 octane fuel should not exceed 30 degrees. For engines on 100 low lead, 32 is the limit. Beyond these numbers, the engine could be aggravated to detonate.
Each of our Distributors is marked on the underside with its mechanical advance and the beginning and ending rpm of its curve. Thus, if you have an engine you’re going to run on 93 octane fuel, and your Distributor says “18-1,000-2,400,” use a timing light to set the static timing to 14 degrees below 1,000 rpm. With the plane tied down, raise the rpm above 2,400 and verify that the total advance does not exceed 30 degrees. A dire warning: Never touch the ignition wires while the plane is running and turning a propeller. There is a remote possibility you’d get a high voltage shock and inadvertently flinch into the propeller. It’s a very remote possibility, but a builder in Australia did it and was lucky to keep his fingers.
For a better understanding of ignition timing please click on this link:
The above photo shows four point cams. Occasionally people ask if they can recurve distributors at home. It would be a very difficult process, and while you might achieve some results, a lot of the fine tuning we do to distributors is very difficult to see. Off the end of the screwdriver is the part of the point cam that the counterweight touches. Notice the four different profiles shown here. There are six different common Corvair profiles. The upper two are ground to match templates we’ve developed to produce ignition curves that suit aircraft use. The upper two point cams appear shinier because they’re nickel plated. We later switched to chromed ones we use now on all models.
Above is a wiring diagram that shows the basic layout of my ignition system. This page is taken from our 601 Installation Manual, so it includes some of the wiring associated with fuel pumps. The key elements of the design are redundancy, low power consumption and low voltage tolerance. It’s also immune to voltage spikes and high temperatures.
With our system, notice that you can fail one of the coils or one set of points and still have 100% power available through the backup system. Once every few months, a builder will propose a system that has three pickups and a wasted spark system using three coils and two plug leads from each coil. I know these systems well, and they’re not safe to use in Corvair engines because with three coils and three pickups, you’re statistically more likely to have a failure and when you do, you’ll be immediately down to 66% power. However, the dyno shows that dragging two dead cylinders means you’re really down to 50% power and some Corvair powered airplanes will not climb on half power.
The above 2001 photo shows the firewall mounted electrical box from our test mule at the time, The Skycoupe. We put this together so all the electrical components and flow cool air over them. The Wagabond has something similar. This function is done on aircraft like Zeniths by having the coils and the MSD 8210 behind the firewall. The only difference in today’s method is the use of Bosch Blue Coils, readily avaiable from Great Plains Aircraft. The Accel coils shown above must have external ballast resistors, which are internal on the Bosch Blue Coils. The top shelf houses the MSD 8210 coil switch. There’s some discussion about the use of the Mallory equivalent of this part. The system will work with either; it does not care. If you look at the wiring diagram above, you and identify most of the parts in the system.
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