Pusher problems?

Help Support HomeBuiltAirplanes.com:

mde168

Member
Is anyone using the half vw in a pusher configuration, or know of any problems with using the motor this way?

Ace_Plumber

Well-Known Member
I am new to this forum and since no one else has posted an answerer I will tell you what I know about 1/2 vw pushers.Not much but for what its worth here goes.First off yes they can be used for pushers,some of the UL crowed have done so. But there are some differences in the way they are built.You will need Two sets of main bearings, A thrust bearing is used on the back of the engine (cut end) as well as the front. The flange on the bearing can be removed if it interferes with the mag drive. Also if you use a stock VW crank you must enlarge the inside of the thrust washer by about 1/8" bigger than the main journal so it doesn't interfere with the radius on the crank. This information comes from Morry Hummel's engine planes.I purchased a set but never used them as I found an engine that was already complete> I am using it in my Hummel Bird (tractor configuration). I hope that this info helps someone as this is an old thread. Does anybody care any more? onder:
Happy building, A.P.

Last edited:

Greg Mueller

Well-Known Member
Yes!
I'd like to build one. I'd like to find the book.

Ace_Plumber

Well-Known Member
Thats great Greg,a couple of places that sell 1/2vw plan sets. Hummel Aviation sells plans for $45. Bill Bronson sells a set of plans and narrative for$75. I believe the Hummel plans are four sheets of drawings and ten pages of instructions. Bill bronsons is sixtyone pages total. I don't know how many of those are drawings. I think they both have options for the pusher configureation. Lenard Millholand sells a set of plans for the full case (uncut case) version. Also there is the Car 1/2 vw,I think Great Plains sells plans. Good luck to Greg, it's a fun project and it makes a good che errrr inexspensive engine.

HBA Supporter

HumanPoweredDesigner

Well-Known Member
So you can't just transplant an auto engine into an airplane because the crank shaft barings are not designed for force from the thrust direction? Or is that just something extra you do since you are cutting it in half anyway?

What is the benefit of using a half VW engine (35 hp and 80 pounds) instead of a motorcycle engine (35 hp and 40 pounds)?

Ace_Plumber

Well-Known Member
HPD,thats exactly right. The VW engine as used in the automobile has thrust only from the camshaft drive gears and clutch engagement. There is a thrust surface on one main bearing to compensate for this. But if it is intended to be used for a tractor rather than a pusher then a thrust surface has to be added to the other end of the crankshaft as the thrust is opposite than the original design. Also the Half VW develops its torque at a much lower RPM than a motorcycle engine. generally you would need to us a PSRU which would increase the weight significantly. But don't take my word for it check for your self. It's been many years since I have looked at these things.

AP