Thrust angle on pusher highwing
ab...@my-deja.com
I hope someone out here can point me in the right
direction.
Upon fitting a four-stroke motor on my Beaver
RX550 which has a similar configuration as the
Challenger,
I am making a new mounting frame which allows the
possibility of now changing the thrust angle.
The idea is to tilt the motor down 3 degrees, to
lessen the trim required on throttle changes.
A larger clearance between prop flange and rear
boom will also allow the fitting of a larger
propellor.
Hopefully the increased efficiency of a bigger
prop will go some way towards compensating for
the extra weight!
The Beaver, though, cruises nose low with the
bottom of the flat airfoil already a degree
negative.
Original configuration had thrust angle parallel
to bottom of wing. Would 3 degrees down be too
much?
(New engine has 10% more horsepower, and a small
loss in cruise efficiency would be acceptable.)
Who will give me the wisdom of their experience?
No need to re-invent the wheel!
Best regards,
Abraham Kruger.
ab...@yebo.co.za
P.S. Would like to e-mail A.S.A.P as well but
cannot find an address.
Sent via Deja.com http://www.deja.com/
Before you buy.
jay
different. It is according to the cowl/windshield AOA and CG. The light
weight of these crafts make most mods trial and error.
Jay
<ab...@my-deja.com> wrote in message news:8cqqo4$unr$1...@nnrp1.deja.com...
Jay
>
>Hi Fliers! (Second try, sorry if first did post)
>
>I hope someone out here can point me in the right
>direction.
>Upon fitting a four-stroke motor on my Beaver
>RX550 which has a similar configuration as the
>Challenger,
Rule of thumb... If your thrust angle is the inverse of your angle of
incidence at cruise, you will get the most power, however, if the thrust vector
line passes through the center of gravity of the aircraft, you have the most
stability.
Jason
james scarlott
Jay
>
>jason you want to translate that so all can understand I.E. laymans terms
thanks
>
>> Rule of thumb...
Ok... Say your aircraft cruises with it's wing at a 12 degree incidence
relative to the line of motion and you place the engine angle to be parallel to
the line of motion in that instance, you get the most power. Your engine is
placed at an angle inverse (-12 degrees) to the wing. If, however, your thrust
line (the imaginary extension of the prop shaft) passes through the center of
gravity of the aircraft, you get the most stability and little change of trim
due to throttle changes. You will have to re-trim due to AIRSPEED changes
though. Best case is to have the thrust line pass through the CG AND be
parallel to the line of motion... Was that OK?
Jason
Mark Smith
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, If, however, your
thrust
> line (the imaginary extension of the prop shaft) passes through the center of
> gravity of the aircraft, you get the most stability and little change of trim
> due to throttle changes.
wouldn't the center of drag be a better place to align the engine so
power cjanges would not pitch the plane up and down.
The offset CG thrust line problems would be temporary,,,,,,
--
Mark Smith mailto:tri...@trikite.com
Tri-State Kite Sales
1121 N Locust St
Mt Vernon, IN 47620 http://www.trikite.com