[simpits-tech] Need a plan

[Bubba]

Phoenix2000 at phoenixcomm.net wrote:
>
> I have messed about with a few Corvair Engines in my
> back-in-the-day.. Its way heavy and the manifolds are part of the head 
> casting itself...
> Crown Eng in Calif.. did my heads to mount Webers and beter exhaust
> systems. They had to mil the old headers (intake & exhaust) off the head 
> and weld
> plates to it. Then it was a $$ in 71 dont know if they still are there.

Not a problem. I have a lathe and mill in the garage and access to every 
kind of welding equipment known to man. Average installed weight, with a 
starter, more aircraft friendly carb, and alternator is 250#. Yes that's a 
bit heavy, but the KR2S is known for being tail heavy and twitchy in pitch.

> Also you mentioned that you want to  get a custom ground cam.. ok but
> car engines make power at HI RMPs
> and not LOTS of torque. your motor has to turn over at 1500 rpm thats
> about max for the prop. (but the motor
> touque is at much higher rpms  good luck

For a 52" prop 4500 RPM is still in the realm of efficiency. It's getting 
close to transonic by then, especially above 10k feet, but it'll work. 
However, the plan is a 4000 RPM redline and 3500 RPM cruise. The TBI 305 in 
one of my Camaros has a redline barely over 5000 and I know peak torque is 
around 4300 RPM. It weighs a ton and a 52" prop is just way, way too small 
unless there were at least 6 blades. A truck cam can bring the peak torque 
down to about 3500 (and add 30% to the peak torque) which would work great. 
The problem is that a small block Chevy weighs more than the bare airframe 
;) A 250 pound engine set up to make peak torque between 3500 and 4000 will 
work great in this particular plane. It needs nose weight, the crank 
centerline is very low so it has to swing a small prop, and the plane 
doesn't weigh anything (980 pounds gross).
-- 
Steve
mysticz28 at swbell.net
He who seeks will find, and he who knocks will be let in.