What happened to the Ultravair?

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Daleandee

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The heads are better than the VW
How much machine work would it take (if it's even possible ... I haven't looked) to cut the Corvair heads down and make them fit a VW? I'm sure there's no way to do that or someone would have by now.
 

Daleandee

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Head stud patern on the Corvair is 80mm x 84mm. The VW is 75 x 81.
Thanks for that. I know that the 3.0 Corvair conversions use VW cylinders but they have to have mods done to the holes to make the alignment work. I never bothered to look at the heads to see what the difference was.
 

Vigilant1

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Are the 6 cyl Corvair cases, heads, camshafts, and cranks so common and so cheap that it makes sense to cut them up to make a 2 or 4 cyl engine?
 

Vigilant1

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The big Corvair is 3300 cc. 4 cylinders is 2/3 or 2200 cc. So it would make the same hp as a 2180 cc VW.
Right. And they are still making brand new parts for the VW Type 1, no need to cut anything if you want 75 HP. Still, apparently the idea of cutting up Corvair cases and heads has fans for various reasons. I'm just wondering if getting old parts to modify is easy and cheap.
 

Flyguyeddy

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I just picked up 4 engines for $450. One of which will be used for a sonex, one sold as a core to recoup some cost, and one of the others will be used for a 2 cylinder
 

TerryM76

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I picked up two cores a few months ago for $500 but they came with nearly $2k worth of new parts. It's not hard to find useable core for less than $250 each. I'll soon have enough parts to build up a 3.0 and then wil need to figure out which airframe to bolt it on.
 

Daleandee

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Corvair cores are plentiful enough. I found a core engine (1964 long stroke) on Craig's list. The guy had the engine and tranny for $300 but I didn't need the trans and just bought the engine at a reduced cost. I honestly forget what I gave him for it but it was somewhere around the $150 mark.

GM made 1.8 million Corvairs: US Production

They do make a fine airplane engine ... but I am biased.
 

wanttobuild

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MarkW
How are your projects doing?
I havent been on hba in a while.

Is the four banger corvair a worthwhile project?

I recently noticed the briggs v twin making up to 48hp. efi, electronic throttle control. Offering a 1 5/16in splinded output shaft . no mods necessary other than air filter. well it needs a redrive. I am speaking of the marine offering, advertised as 40hp.
 

skyguynca

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If you want an alternative to the 1/2 VW just use an OMC Cushman 222. Search the forums for the discussion. It's A LOT easier to convert and a bit lighter than the 1/2 VW. Check Ebay from time to time.
The cushman 222 is less hp, 18 to 22hp. The cushman 222 weighs 90lbs ready to fly.
Yes the 1/3 corvair is more work, but depending on cylinders and head choices, it can be from 28hp stock to 35hp. With the right cylinders only 72lbs, but nikasil cylinders are not cheap. With big bore vw cylinders 76lbs.

How do I know? I am the guy who got the rights from Fletcher Burns. So realistically while I did not come up with the conversion, it is mine and has been for several years, 11 I believe.

For the past few years I was giving the plans away on the Ultravair Yahoo Group....well yahoo shut down the groups........

If you would like the plans, PM me.

David M.
San Jose, CA
 

skyguynca

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Thanks for that. I know that the 3.0 Corvair conversions use VW cylinders but they have to have mods done to the holes to make the alignment work. I never bothered to look at the heads to see what the difference was.
The only mods are to the fins to get the studs to clear. You are still using corvair heads and block.

David M.
San Jose, CA
 

Bill-Higdon

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The only mods are to the fins to get the studs to clear. You are still using corvair heads and block.

David M.
San Jose, CA
They start with "stock" head block but you cut them down to go from 6 cylinder to 2 cylinder. As for the cylinders, yes it's a mater of "jiggering the mounting holes on the cylinder to match the crankcase & heads.
 

skyguynca

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As I said before, not only have I built a few, I have the rights to the design. I am familar with building the Ultravair. I am a machinist and welder so I did all the work myself.

You don't actually need to "jiggering" the mounting holes on the cylinders at all. There are no holes on the cylinders. You take a 1/2 ball mill or a cut off wheel and a file and remove the fins that will interfere with the studs that go from the block all the way thru the head.

Yes you do cut the heads. Which is really easy and makes it alot cheaper. I generally look on the corvair web forums and buy heads that have the center cyl head or one bad end on the head which no one can use, usually it just costs the shipping. You only need to make 2 head for the ultravair.

David M.
San Jose, Ca
 

Bill-Higdon

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As I said before, not only have I built a few, I have the rights to the design. I am familar with building the Ultravair. I am a machinist and welder so I did all the work myself.

You don't actually need to "jiggering" the mounting holes on the cylinders at all. There are no holes on the cylinders. You take a 1/2 ball mill or a cut off wheel and a file and remove the fins that will interfere with the studs that go from the block all the way thru the head.

Yes you do cut the heads. Which is really easy and makes it alot cheaper. I generally look on the corvair web forums and buy heads that have the center cyl head or one bad end on the head which no one can use, usually it just costs the shipping. You only need to make 2 head for the ultravair.

David M.
San Jose, Ca
David,
I forgot you owned the rights for the Ultravair. An interesting side notw some of the early VW engine aircraft conversion for big bore cylinders used corvair, before the German cylinders became available in the,USA Robert Huggins did it for his conversions. He also had the first "5th" bearing for the Corvair http://www.contactmagazine.com/Downloads/Dec-1962.pdf
 

Flyguyeddy

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The 5th bearing is great for the full corvairs.
Id like to see a nice smaller unit for the 2 cylinder engines.

Can you post some pictures of the engines you have built? What do you do for a carburetor? Did youbget any info on the charging system fletcher was working on? I have so many questions!
 

skyguynca

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I am actually starting one here next week or so. I will post progress pictures here. When I make the Aluminum prop hub I cut a alternator pulley on it and use a john Deer alternator (really a dynamo) and it works fine.
 

wanttobuild

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Here is an excerpt from William Wynne's website.
January 2008 At The www.FlyCorvair.com Hangar

"we've made arrangements with our friend Fletcher Burns, designer of the 1/3 Corvair conversion, to further develop and market the Ultravair Engine. Fletcher's real forte is development, but marketing, like many highly skilled technical guys, never really was his bag. We're bringing his egnine mated to Ed Fisher's 1991 Oshkosh Grand Champion Skylite to Sun 'N Fun this year. At that point, we'll reintroduce an expanded version of Fletcher's Manual that will include all we learned by mating it to the Skylite and flight testing it."

Well its too bad this didn't come true, never thought about the ultravair mated to the skylite, would probably make a nice ultralite.
Both parties are here on HBA, hope that they can work something out!

Might as well go ahead and squirt a little Nitrous for a little extra kick when necessary.

Addicted to climbing has the rights to the Skylite I believe and Skyguynca the Ultravair.

Maybe they can work it out!
 
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