All,

When the motor is fitted in front on a plane for normal/standard operations it is said to incline slightly to the right and down... But how would one mount for a pusher?

Pankaj

If your prop is 1/3 of the WS, you do not seriously need this (port/starboard) shift for EP as required with IC engines to counter the torque.

Now for pushers, keep in mind that instead of down, you *may* end up tilting the motor shaft a bit up so that the Props make a slight positive 9-11 degree with the fuse plane i.e the prop face little bit towards the 'sky' rather than religiously parallel to the rudder vertical axis.

My little experience with the pusher conversion of the al cheapo Chinese plane is that since prop is pushing the plane from 'behind' the CG position (1/3 from the the leading edge of chord), it would push the plane slightly nose down. The Since the thrust force is on the 'other' side of CG as from puller config, the little 'down' angle should be replaced with little 'up' angle instead.

I bet veterans like Ashta, VC , Sai etc would give more conclusive opinion.

http://www.rcindia.org/electric-planes/multiplex-easy-glider-pro-conversion-to-pusher-like-easy-star/

Check this out

Sai

"

Quote from: ujjwaana on March 05, 2010, 05:31:31 PM
If your prop is 1/3 of the WS

I don't understand the "1/3 of the WS"

Quote from: Rao on March 05, 2010, 08:03:53 PM

I don't understand the "1/3 of the WS"

I read somewhere that for EP powered planes, if your propeller size is lesser than 1/3 of the wingspan, then you don't need to worry much for the torque resulting from the rotating prop.

"I bet veterans like Ashta, VC , Sai etc would give more conclusive opinion."

Firstly, you are making a BIG mistake by putting my name in the same league with these stalwarts. I would feel insulted if I were in their place. 

I spoke with Ashta Sir (my guide and inspiration) and he advised me to keep the prop / motor absolutely parallel to the fuse / horizontal axis. I thought the same way as you did and felt it would have been better to have kept it angled slightly ( 10 degrees or so) up. I have taken his good advice and kept it absolutely parallel on my Raptor.

Cheers!

VC

In the guideline for trainer design, there is a relationship between the chord and the prop to LE distance. What happens for a pusher? In Sai's model, the motor is right next to the trailing edge. Does it matter if I put the pursher on the nose (with a proper mount offcourse) or right behind the elevator?

Quote from: VC on March 05, 2010, 08:35:02 PM
I spoke with Ashta Sir (my guide and inspiration) and he advised me to keep the prop / motor absolutely parallel to the fuse / horizontal axis. I thought the same way as you did and felt it would have been better to have kept it angled slightly ( 10 degrees or so) up. I have taken his good advice and kept it absolutely parallel on my Raptor.

How did this config work out on the field?

http://flitetest.com/articles/Motor_Angle_and_Thrust_Vectoring_Experiments

Now the question... why did did he feel the motor pointing downwards was better, as opposed to what is commonly known (pointing the motor a bit upwards is common for pushers).

Hello anwar ji.
What i feel is that his model in quite different than the pusher like easystar etc.its just a flying plank. On the other hand wanted to have suggestion on the both
angle of attack and motor angle for the model i am making.... your suggestion would help a lot.
I have read on this in this forum but no one says the thumb rule ...

my post - http://www.rcindia.org/electric-planes/scratch-building-a-look-alike-of-axn-floater-or-fms-800-or-easystar/msg105992/#new

Thanks.
Saurabh

As i can understand the test plane lacks the lift force since the wings are not that effecient to give lift as a result to downward thrust.