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Hand Prop to Electric Start Conversion

Posted: Sat May 13, 2017 7:58 pm
by teamtulsa
We currently have a hand prop std Corvair engine in our Pietenpol with belt and fan blower setup that we wish to convert to prop air and electric start. We have seen that a Ford Taurus starter ring and a Subaru starter with work. The engine the engine to 15 yrs ago to William Wynne's manual # 7769, but now it seems the parts/numbers we need are all for the newer 5th bearing Corvair engines. Has anyone converted from hand to electric start on a older Corvair powered Piet or can you direct us somehow?? We would love to fly her to Brodhead this year from Tulsa as well. Thanks in advance!!

Re: Hand Prop to Electric Start Conversion

Posted: Sun May 14, 2017 9:50 am
by EAB4
Hi steve
its a few years old, but here is a link to a story on the Flycorvair site that will give you an idea of whats involved in making the change. ... pietenpol/

I do know the Taurus ring gear and Subaru starter are not used anymore- the new ring gear is stronger and less prone to cracking, the new starter is lighter and smaller. It might be a good idea to order a new manual to see what has changed over the years.

Here is a link to the parts ordering page:

Another forum all about the Corvair powered Pietenpol

This email will put you in touch with William Wynne as well as Dan and Rachael Weseman at Sport Performance Aviation.

They will be able to answer any questions you have about the conversion!

Hope this helps

Re: Hand Prop to Electric Start Conversion

Posted: Sun May 14, 2017 11:54 am
by taildrags
Steve; if you're not on the CorvAircraft list, I'd be happy to put your post up on that list to see if anyone has info on that combination. I doubt that there are many (if any) builders or pilots who are still using the belt and blower setup though. I may have some pictures of a Piet with the belt and blower but I don't remember if it had a starter. I'll check.

Re: Hand Prop to Electric Start Conversion

Posted: Sun May 14, 2017 12:09 pm
by taildrags
Well, here are the pix of the belt/blower Corvair that I have, but it's not possible to determine whether it had a starter or not. What seems obvious is that the standard conversion parts that William designed will not work with this setup because something has to either bolt to the top cover or to the heads and neither of those is accessible with the old blower in place. You may be on your own here.

I will point out, however, that there is an electric starter conversion that used to be available for early small aircraft engines like my A75-8, using a cordless electric drill as the starter and engaging it mechanically by pulling the drive teeth into engagement with the starter ring gear that way. You can see pix and a description of it on the National Aeronca Association bulletin board right here:

Re: Hand Prop to Electric Start Conversion

Posted: Sun May 14, 2017 12:21 pm
by EAB4
the blower, top cover and shroud are not used in the conversion. The new top cover is a flat sheet which leaves plenty of room to mount the starter

Re: Hand Prop to Electric Start Conversion

Posted: Sun May 14, 2017 3:06 pm
by taildrags
EAB4, thank you... I understand that the modern (WW) conversions don't use the original tin and blower and all that... I have been in the Corvair movement for 20 years and I own and have studied William's videos and four different editions of William's conversion manual in detail, including the latest. It's just that Steve said their engine is the old-style conversion, thus my reply. I see no benefit to keeping a blower-style setup except if the airplane is flying like that, it will have to be taken out of service to convert the engine the modern way, and it will cost money. Not saying that would be a bad thing though, because most of the engines that were converted using the blower and belt setup also retained the automotive cast pistons, cam, ignition, and all the other things that really ought to be changed to make a truly airworthy engine that puts out its best power where our airplanes need it. At the very least, dispensing with the oddball belt and blower setup would save weight, complexity, and the power that the setup robs from the engine.

Builder's choice though.