Gil's Corvair

[grdev]

I have my cases cut into, my crankcase cut, and now I'm looking for a local machine shop to mill my cases and drill the back plate before I ship out the engine to Scott at Hummel engines that is going to do my crank and camshaft. He told me he thinks he can machine the cam without removing the gear. Now I will try to insert photos!

[Justin]

Looks good! Did you use a bandsaw? Can a giant belt sander used to resurface heads work for the case?

[nheistand]

Not seeing much about the Corvair engine. Once there was a company near me that was making parts for the 2 cyl Corvair ultralight engine. I have not found them lately. The 2 cyl VW is probably easier to do and affordable. I like the idea of a simple cut the crank, cut the cam, cut the case, and make a 2 cyl from the Corvair. I know it can be done. However, the full case version of the 1/2 VW is surely easier?

Norm Heistand  my .02

[grdev]

I used a saw zaw with a long blade. I think it is a good idea to have the cases machined so there won't be alignment problems with the oil pump and mag.

[Bob S.]

I would like to see how the oil pump and magneto are attached....having never seen the plans for the 1/3 'vair...

[grdev]

There is a plate that is machined for the back plate. on the end of the crankshaft there is a puck that turns the mag. the oil pump is driven by the camshaft that has a slot machined in the end of it that matches the driveshaft on the oil pump. The oil pump and mag both attach to the back plate. Hope that helps, check out the yahoo web site ultravair2 lots of photos

[grdev]

Heard from Ultra Vair today and my engine is coming right along. Case half's were off a little so they are milling some off the case halves and then line boring the case. It will have a 1.6 ratio poly belt re drive so I will have to find out what size prop to use. I have no idea so I thought I would talk to the people at Culver props. .

[weasel]

Call Frank at Performance Propellers USA. He makes good props.

[Steve]

Heard from Ultra Vair today and my engine is coming right along. Case half's were off a little so they are milling some off the case halves and then line boring the case. It will have a 1.6 ratio poly belt re drive so I will have to find out what size prop to use. I have no idea so I thought I would talk to the people at Culver props. .

Check this out in the attached 2 screen shots - it will be very close:

Going to have 8" of clearance under that prop with fus upper longeron level?

Prop size calculators...

[grdev]

Steve, a couple of questions I will need to answer before I can tell you the distance under the prop. One, what is the increase in height from the engine center line with the redrive, and two at what height should the prop center be in relation to the centerline of the firewall or what is reasonable.
I'll email Ultra Vair and ask for the prop height.  Is 3300 RPM a good top RPM for the UV & is 29-30 HP a fair estimate of the actual HP it will produce? What ground clearance are guys getting now with their XL's? I know the inspector on my DE anted about 9" of clearance, but that is something I didn't think to ask about with the redrive
A redrive prop from culver is over five hundred dollars, so I want to make sure I get it right
Thanks Gil

[Steve]

Steve,   Is 3300 RPM a good top RPM for the UV & is 29-30 HP a fair estimate of the actual HP it will produce?
A redrive prop from culver is over five hundred dollars, so I want to make sure I get it right
Thanks Gil

Those calculators are based on (cruise speed & engine power) - the estimate shown I consider to be [conservative]... I advocate letting the UV turn a little faster than some - you are going to be in the upper end of gross weight... I like the way Frank's props are flexing on these small engines...

[grdev]

If my plane comes in over the limit, I'll just get an N number, rather not, but is really no big deal to me. My main problem has been finding an instructor for the bi annual.  I'm more interested in  good climber than a speedster. I have managed to drop 50 pounds of body fat and I hope to be under 200 pounds by the time the plane is done.  getting close. Flying down here in the Mark Twain National Forest area there aren't a lot of good options to put a plane down in an engine out situation. flat green fields are few and far between. I want a good short field performer like the Back yard flyer, if possible

[Steve]

If my plane comes in over the limit, I'll just get an N number, rather not, but is really no big deal to me. My main problem has been finding an instructor for the bi annual.  I'm more interested in  good climber than a speedster. I have managed to drop 50 pounds of body fat and I hope to be under 200 pounds by the time the plane is done.  getting close. Flying down here in the Mark Twain National Forest area there aren't a lot of good options to put a plane down in an engine out situation. flat green fields are few and far between. I want a good short field performer like the Back yard flyer, if possible

Extend your landing gear to get the 9" clearance - there are long discussions about the short field advantage of this over in the Yahoo Group Conversations... The 2 blade prop is superior on the slow UL's... I always advocate ground running the adapted engines for 10 hours (normal crib death period) - don't fly this plane in the first 40 hours where you can't do an immediate landing on a good spot...

[rockiedog2]

i don't know squat about the UV. how does it get away with running a redrive and the Vdub shreds the belts in no time...something about it used to be a 6 cyl?

[Steve]

i don't know squat about the UV. how does it get away with running a redrive and the Vdub shreds the belts in no time...something about it used to be a 6 cyl?

Here's a couple vid's of the Citroen 2CV redrive engine in action:

https://www.youtube.com/watch?v=NyZZkEoGdzY



The UV bottom end is more like the Citroen than the 1/2 Vw with the modified German Crank...

There are rpm points that I see the Citroen showing the typical opposed 2 cyl shaking dog moves, I guess they don't dwell there...