Mark Langford's KR2S Corvair Engine

Corvair KR2S Engine

revised March, 2004

If you are going to build a Corvair powered aircraft engine and don't have years to do the research yourself, you should buy William Wynne's conversion manual (see his web site below). He's not real good at answering email or phone calls, so just mail him a check for $59 (that includes the shipping) to the address given on his web page. You can order his Corvair Conversion Manual from Wicks Aircraft or Clark's Corvair online. Armed with only his manual you can probably build an aircraft engine based on the Corvair. There are several parts that will need to be machined, but it's not prohibitively expensive and he includes the drawings that you'll need.

If you want to go ahead and start foraging for an engine, see Pat Panzera's Engine ID page along with his Head ID page lists which heads and cases should appear in which cars. Print it out and take it with you when you purchase your engine. And go ahead and order the Clark's Corvair and Corvair Underground catalogs. They are both full of good information (URLs available back at my main Corvair page).

It's been my experience that whenever you tell somebody you're building a plane, if you also mention that it will be Corvair powered, you'll usually be offered a lead on somebody that has one or several of them. Both of mine cost me $100 each. You can also make great strides in your search by going to a local Corvair club meeting (see the Corsa web site below) and announce that you're looking for a 110 HP engine. You'll probably leave with several.

Otherwise, joining the CorvAIRCRAFT list (free and very informative) and perusing the web sites below will get you a very nice head start.

CorvAIRCRAFT is a mailing list dedicated to Corvair engine construction for homebuilt aircraft. To SUBSCRIBE to the mailing list send an email message to The message can be blank, it'll still work.

Below is some text that I snatched for the Aircamper website at, which has been off-line lately for some reason. If/when they bring it back, I'll gladly delete it, but for now, you really need to read this.

Picking a 110 hp engine

Here's how to pick a 110 hp engine, quoted from Brent at the Corvair Center Forum:

"Fully half the Corvairs built from 1965-67 have a 110 HP Powerglide and the suffix code for this engine is RH- its common and a good engine. A worn out core that still runs is worth a couple hundred dollars, a really good used one is worth about a grand. I'd buy the best you can find, its cheaper in the long run.

T1214RH would be an example, all will have a number like this-the number indicates the date of engine manufacture, in this case, December 14 of whatever year-

Powerglide engines are superior rebuild candidates generally speaking, as the automatic limits the abuse potential. Things like connecting rods have significantly greater service life left in them on Powerglides of equivalent history to manual transmission engines of similar type.

The RH code means also that the engine had neither factory Air Conditioning, nor an Air Injection Reactor- this is a plus, as ( the latter especially, ) they both increase engine temperatures somewhat.

Normal lifespan of this engine in normal service is 150,000 ish miles. Many have gone twice that far. Also, many 1966 versions of this engine have the 95 HP cam, as Chevrolet apparently swapped it in production for a while-
here are all the suffix codes for 95-110 hp engines for 1965-1969


most combinations are oddballs, like AIR or A/C combos, or manual transmission jobs.

Theres not too much risk of getting a 140/145 cid engine in a later case, but things can happen."

Selecting the right Corvair engine for your homebuilt
by Robert Finch.

Reprinted from the May, 1979 Air-'Vair News letter edited by J. Hartley Locher... (a copy of which was provided to Grant Mc Laren by Vi Kapler -1033 Forest Hills Dr., SW, Rochester MN 55902) ... interesting reading from an era when BHP had been successfully flying a Corvair for at least fourteen years.

Corvair engines can be expected to produce from 60 to 140 horsepower in direct-drive configuration, and from 80 to 150 horsepower in rear-drive configuration! Take a look at a list of of homebuilt airplanes and the horsepower engines they require or will accept and you can include about 90% of all homebuilts in your list of airplanes that can use from 60 to 180 hp Corvair engines! Of course no homebuilt designer wants his airplane. built by a homebuilder to crash and hurt someone, so he will strongly advise against the use of any but the most reliable engine for his design.

Burt Rutan of Vari-Eze fame advises if you want to try a non-certified engine, put it in a proven airframe such as a Piper Cub. At least that way you don't have to cope with two unknowns on your first flight. This one factor is probably the main reason such a large number of homebuilts never fly. I would suggest using a Cessna 150 as a test bed for your experimental Corvair engine set-up. or buy a used homebuilt like a Pietenpol that has many hours of trouble-free flying time on it. and you will probably get your Corvair engine in the air a whole lot sooner!

CHOOSING A SPECIFIC ENGINE ... l) A new one from Chevrolet is the best and cheapest way to go in the long run ... yes, you can still buy a new 145 CID 102 hp '62 -'63 engine from the parts department at your local Chevrolet dealer. The price (early 1978) is averaging $800.00. 2) The second-best engine would be a medium-time, never-over-hauled 1964-to-1969 engine, and just do a seal job on it without taking the heads off. Just inspect it for sludge deposits, and leave it together. It probably would run five years that way. 3) Find a high time. 100.000-mile engine that needs an overhaul because of no compression on one or more cylinders. and expect to spend $800 for parts and outside labor to TOTALLY "major" it. That price for an overhaul is not so bad when you find out that a crankshaft for a Continental 0-200 costs over $1100.00!!! 4) The last choice is any Corvair engine that has 'just been overhauled." especially if it a ring job and not all-new cylinders assemblies. From long, long experience. I say you can expect to have problems with this kind of an engine if you don't go all the way through it and thoroughly inspect every single part for damage caused by a poor overhaul job. Expect to spend at least as much for parts for this engine as you would DON'T MODIFY! ... You may need to replace a part to get home from Oshkosh; Cheyenne. Wyoming: Lompac, California: or etc. You can find useable Corvair parts in any of these towns. but you would have a heck of a time trying to get a 140 hp cylinder head with a special heli-arced intake. etc.. even in Los Angeles or New York City. You could limp home with one 140 hp head and one 110 hp head if you had to. so try to keep everything "off the shelf if at all possible.

CONVERTING THE ENGINE FOR AIRCRAFT USE ... dual ignition is usually the first topic to come tip. Dual ignition is still used on all certified aircraft engines today for three main reasons: I A 140 hp Lycoming has huge 5.125 inch diameter cylinders with a dis-placement of eighty cubic inches in each cylinder!! And the spark plug can just not ignite that much fuel in the time allowed for combustion. (A 140 hp Corvair has a 3.4375 inch cylinder diameter and a displacement of only 27.3 inches per cylinder. and a modern squish-chamber cylinder head design. (The Lycoming or Continental engine has 2 spark plugs cylinder to from fouling out the spark plugs. whereas Corvair air engines run just fine with one plug to fire the mixture!! Reason #2) Most people think that dual ignition is a safety factor. The Feds also consider it a safety factor. Reason #3) The Feds say you must have dual ignition!! Then, for safety. why don't they make you have dual pilots, dual engines? dual landing gear? dual propellers? dual carburetors? (It one iced up. you could switch to the other?) dual valves, dual pistons. dual wings, rudders. etc.. etc... well, the point here is that if any of these systems is in good shape and doing its job you don't need but one of any given system. Also, if you did have dual mags on y our Corvair. they would probably deteriorate at the same rate, and then what do you have? Dual bad mags?

"Corvair Distributor ... If rebuilt every 50.000 miles or 1.000 hours, and if the points and condenser are replaced every 200 hours. it will do the job just as good as ANY magneto or better than any transistor ignition available today. All you need for ignition is the stock distributor 12 volt coil, a dropping a resistor like is used in early Corvair ignitions and a small motorcycle battery and a means to keep the battery charged. I feel this would be much safer than to try to adapt dual magnetos to a Corvair engine.

DIRECT/DRIVE OR GEAR DRIVE? ... Gear-drive costs more weighs more, takes a lot longer to set up the first time but allows from 50%-100% more power output. It can be almost as good as an extra engine at much less cost and much less weight. The question is. do you need the extra power. or will the airplane perform adequately with a direct-drive Corvair engine putting out approximately 70% of its rated horsepower? The answer to that question is strictly up to the individual.

"By now, because of those who have successfully flown Corvair -powered airplanes. we know for sure that the Corvair makes a good airplane engine. The main reason for picking a Corvair engine over a Continental 0-200 is that it costs just about ONE TENTH as much in any given condition, to say nothing of the fact that it is ten times smoother running than the 0-200. every town and hamlet has a Chevy parts department and even the local auto wrecking yard has usable parts!" (end)

This article is article is not presented as authoritative advice from any member of the BPA. It does raise many interesting topics of discussion. If you are considering using a Corvair engine to power a Piet or other aircraft, discuss your project with BPAers who are successfully flying Corvair-powered Pietenpols. (gem)

Return to Mark Langford's KR2S/Corvair engine project.