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Corvair Engine

RV3bpilot

Well Known Member
I took some time but I have my Corvair engine running great in my RV3. It's climb rate is like that of a 100 hp. Continental engine but it keeps climbing even at high altitudes because it is turbo charged, I have taken it up to 14,000 ft. the other day without any problems and still had a climb rate of 700 ft. per min..
It's speed it like that of a 125 hp. Lycoming at low altitudes, and like that of a 150 hp. Lycoming at high altitudes.
It took about one year to work out all the issues with different stuff to include how to drive the propeller safely. But now it is just like any other aircraft engine just change the oil and put in fuel.
 
How much time do you have on it and what sort of prop are you using?

And here's another request for photos.

Dave
RV-3B still on wings....
 
Corvair - now there is a blast from the past - - I bet it is smoooooth.

Just keep good oil in there and get a good oil analysis program going. Those main bearings are quite small, smaller than the VW of the era.

Yes, Lets see some pictures!!!
 
Yes, a few photos would answer a lot of questions. I'd be interested in knowing if you went direct drive to the prop or if you have a gearbox. What type of prop? What attention to bearing loads at the prop end of the engine did you provide? Etc., etc.,
We'd like to hear (and see) more.
 
Corvair Install

I had to make my own motor mount and a lot of other stuff to make it fit.
It is direct drive per my homemade parts. The drive hub has a bearing as same as a Lycoming for stability of the prop. and it has a thrust bearing to keep the prop from pulling on the crank.
It is a Catto prop. 66" long 60" pitch counter rotation. It was damaged on my second forced landing so I repaired it using vacuum bagging process and it is working great.
So far I have 112.2 hours on it.
Here are a few pictures of the installation of the motor. Yes it has fuel injection too.
I use Mobil one synthetic oil in it 10-30wt.
The crankshaft is made by Corvair Specialties, it is 4340 steel billet that have been line-bored, undercut pendulums, knife- edge machined, and partially drilled rod journals, all to keep the weight down to a mere 2oz. heavier than the original crankshaft. The crankshafts have also been heat treated, shot peened, nitrided, and micro-polished.
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Well Done!!

Nice prop adapter design and build, equally nice mod to the heads to make them individual ports, and and and EFI! Too much to comment on!

This sets a pretty high bar for us . .
 
Megasquirt II Fuel Injection

I'm using a do it yourself fuel injection computer called Megasquirt II . I purchased it as a kit and then soldered all the compnets to a circuit board provided in the kit and then down loaded the driver software from their web site and then programed it to suit my motor.
The Megasquirt II also controls the ignition timing which is all adjustable by the user.
This system is very adjustable for manifolds pressures, rpm, spark advance, etc.
When I fly there is nothing to do but fly, the manifold pressure sensor adjust the volume of fuel as the manifold pressure changes. There for it is great for turbo charging.
Do not think that I'm some sort of brainy dude, I had to learn all this by reading all about it and carefully reading the directions that are on the Megasquirt site. I started out by knowing nothing just like when I started building my aircraft, in fact the Rep. at Van's sugested that I get some builders assistance because I did not even know what a cleco was. I never did get assistance, I learned by reading Van's directions in their builders manual and by looking at other builders wed sites..
 
Cool project. Congrats on building all that and making it work! I used to own Corvairs and build engines for them- turbos and road racing ones so I have a soft spot for them. Nice to see one in an RV.
 
That's just too cool. It's hard to keep from looking for a Lear Jet in the background when the sound's up while viewing the video. :)

Way to go!

Charlie
Mazda Renesis FWF in progress on RV-7
 
[snip..]
Do not think that I'm some sort of brainy dude, I had to learn all this by reading all about it and carefully reading the directions that are on the Megasquirt site.

There's a lot of different kinds of smarts... I respect that kind most.
 
What a beautiful airplane and the firewall forward is just off the charts. Kudos for a beautiful project.
Congratulations to you!
 
Corvair Power Now!

Robin: Fabulous job on the installation and final tweaking to make it a "turn the key and fly" a/c! If i remember right, you used to have a GM ECO engine in it didn't you, with the less than sexy looking cowling. Why did you do it again after getting that one flying? Also, what performance differences have you seen between the two installations? Is it harder to make some heat for the cabin with air-cooling vs. water?

Great job, and fly safe!

Doug
 
Simply Superb...

I had to make my own motor mount and a lot of other stuff to make it fit.
It is direct drive per my homemade parts. The drive hub has a bearing as same as a Lycoming for stability of the prop. and it has a thrust bearing to keep the prop from pulling on the crank.
It is a Catto prop. 66" long 60" pitch counter rotation. It was damaged on my second forced landing so I repaired it using vacuum bagging process and it is working great.
So far I have 112.2 hours on it.
Here are a few pictures of the installation of the motor. Yes it has fuel injection too.
I use Mobil one synthetic oil in it 10-30wt.
The crankshaft is made by Corvair Specialties, it is 4340 steel billet that have been line-bored, undercut pendulums, knife- edge machined, and partially drilled rod journals, all to keep the weight down to a mere 2oz. heavier than the original crankshaft. The crankshafts have also been heat treated, shot peened, nitrided, and micro-polished.

Robin,
First, very nicely done!
Question: Did you consider the 5th bearing mod from Dan Weseman at Panther SPA and/or attend any of William Wynne's Corvair U forums before developing your engine?

https://flywithspa.com/corvair-5th-bearing/

V/R
Smokey

PS:My own auto engine adventure included flying my VW powered Sonerai for over a year, enjoying every second. :)
 
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I hope Robin responds personally, but I've had a pretty extensive exchange with Robin. He's an expert machinist and his project was a much about seeing if he could build a prop extension as anything else.

He had an objective to make a long extension that uses the Lycoming sleeve and decoupled the prop from the crank. His first few attempts while seemingly adequate used a relatively small spline to attach the hub-flange to the crank.

The corvair is an exceptionally smooth engine. 6 apposed cylinders with connected heads. Is a rock! But... Any 4-cycle under 8 cylinders will have a negative torque impulse... Ie there's a point in each revolution where the engine isn't in a power pulse and the prop drives the crank. It's pretty small in a 6 cylinder, but it's crucial because it causes any lash (rotational slack) to induce a torque-wrench-phenomena that hammers the connection interface (spline) every rotation.

This phenomena was causing the spline to fail. He ultimately fixed it by creating a disk plate and used a ring of steel dowels to mesh the crank to the prop shaft. He did an amazing job, but most would have given up or just attach the extension to the crank.

That would have had it's own issues as any vibrations from even slight imbalances would transfer through the extension to the weak crank flange, inducing an eventual fatigue and failure. Ala Mark Langford and why weisseman and others created the fat 5th bearing.

It's not easy being different! I like his ideas and I'd love to try to make a similar extension, but geared. But frankly, too much metal fabrication and I love gliding, but not in my RV.


Robin, I hope I've summarized our conversations well enough. I'll edit this if I've misrepresented anything.

-Bruce
 
Pictures Robin sent

This is the prop hub/flange

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This was the first spline Robin Used

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And the hub attachment

vdxxoFxTGLlVhUQpK6o4u01JrTWZ6hD4ctZvUnGldTWGGMosxUCScV4J7FdawHrOQA9SV1hd5SnNdPhVYIs3DLq95yMNHIguS2VH7uzKB3_07FJGi2wgRjkobNcR6_M8qurCF2e3Vo0Ggx5RbCpRppIiqwuANg8VVTfpfkR8S2FHWXjx8sGyuvN4152DMFCKvyjrzKYa3_cGCDmjRh5jcpqZPpqMdejBsC0nmKnACPKY2owECLTnRF6gf9MEQX5qCfI4qI-5fvcR2TgW9iKez5zYrvfmipDzIzW4oENFQXSw3dg0XQWhRkIxCff8fJXFl4eZuiy0bY94KVvqLf2poE5VMK6FH_sUBACHwXIuZ6Li-6G3gEE1y3rxOpSixLX1JTmjpxuwsk3mEISgnz4bmC3_Ob7RqtozCpA_hwttbQYac4pX81S3349m_B3EwT9lTPtZYj2e44cau0bh58hC_fkzsH5KdKY7o265DIwJjdYdE9ZhY-Fxufcc3l08Edy27zLsDgHhPJrCU134qJSaA8RGhMzrhPdQVsWlpCwFo1o8l9q7GRMlRlQ5N1fdFP6_8S0EIlNiElKZql3rAi7pA8N2Ke99dceh4IksBUU=w800-h533-no


This was the second attempt with the plate/dowls

v4_uoU-qbO-14fnyqimsOJ6eamLz4RfKqmmjfYONncZ-PbZp6P_MSjH4fWzhFRu79XxOaMFEjHD8Xh2P8joyLqA_QxoPC-JVq8kh5da_nfRF6rxBlXYrpsByhhAYGJ4yJL--PRAERa_S64Ox0sKAYyPQ9tnw2vSwqF7vOmwpOm3pgj_MHb6MgwdDvRwleJkRy6md4c22fkpLKoV2oK2zSPEU3YuMwMY8tsQhlxuiZfkYY1zZN_JnE1hri8elXH4iSWppMMjZGdUNt0CsiSeWUauc5AyoXzwc5fKIOjoIuBvVc_mO42257B9SXOYokTD9O_X_u79opQh-0bUTSyPAqOSNm2_14f0Gp0LcjIIgWG4c5MfIIInnDNlH_NESnXlvkvwXPhz6T3IWE0Q_DJvWZf4tpWUemZ7ZBLzMeBYthrIhMaY7iBkV6YTvJU3gAojgFJc7zSfqgVNEnFhWfchI1XwbU8IGQ2fXaSetoZKhAlwZTabux937pcyolSNWfDB9b5CMf28SxpVuOiKysIzFu68oJxzmwo5ELfd2jt3pFcNox6D68eHWCCqUXasQr3xP-_iXNSaxm-rM8ba0rMFLpPwR0XLzW1vmgGe7jlYpM00MP27LNQRJx2KL04aSfEXJu-04akO3umX7SWiX1dFhPuHxlVSW-9CK=w640-h480-no


and the plate it went to

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