I see. You are thinking of a pusher. Well perhaps you will need a shield
to deflect any oil vapor that tends to accumulate on the front side of

the

spinner bulkhead. Good point. The Hoffman, IVO and the MT would have the
same problems.

You are right, so far people worry about props other than composite or

wood on pushers due to the loading/unloading as the blades pass behind the
trailing edges of the cowling. All metal props are a no-no. Just the turbo
13b alone is such a significant boost over the IO-360 that we will be happy
with some flavor of fixed prop for awhile.

...Chrissi

Most high speed tractor hombuilts have such a high power to weight ratio

that the fixed pitch prop

can be optimized for cruise and still allow the airplane to take off in

less than 1000 feet.

I am not sure I can say that about canards however. I am not sure why.

Just

an impression I get from talking to people. Perhaps the canard does not

have

enough elevator authority to rotate the wing to an optimum angle of attack
for a short takeoff. If true you will need a variable pitch prop to
optimize both takeoff and cruise MPG.

This is what one prop company claims a variable pitch prop can do for
takeoff and climb.

Of course with a turbo rotary you can always run up the boost and not
worry about blowing the cylinder heads out through the sides of the cowl

:-)

Dave Garber and Greg Richter proved that.

Paul Lamar

The problem is not pusher vs tractor, but conventional vs canard. Canards
are limited in the max cl of the rear wing in order to keep it from
stalling. (short story, there is not enough elevator authority like you
said)  The result is higher take off and landing speed for a canard vs a
conventional configuration of equal wing area.

BTHW Paul, could you send me the graph Vance sent with the different sized
props? I deleted mine like an idiot.

I'm still not sure that I agree that the small fixed pitch prop will work
for my application. It is much easier to make a small fixed pitch prop for a
plane that only flies at 200 mph. One that flies at 300 is quite a different
scenario.

Monty

 
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