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.Head stud patern on the Corvair is 80mm x 84mm. The VW is 75 x 81.
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.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.
The cushman 222 is less hp, 18 to 22hp. The cushman 222 weighs 90lbs ready to fly.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 only mods are to the fins to get the studs to clear. You are still using corvair heads and block.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.
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.The only mods are to the fins to get the studs to clear. You are still using corvair heads and block.
San Jose, CA
David,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.
San Jose, Ca
Id like to see a nice smaller unit for the 2 cylinder engines.The 5th bearing is great for the full corvairs.
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."