Electric Motor Mounting Angle

by Dean
(Gold Coast, Australia)

What happens if the mounting angle of the motor is wrong, non-existent or backwards? Does anyone have any information on how the physics of this works?

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Electric Motor Mounting Angle

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Jul 28, 2008

Motor mounting angle
by: Pete

Hi Dean,
I'm not sure about the mounting angle being backwards! But it can certainly be mounted at various angles, or no angle at all.
The two common angles are called 'down thrust' and 'right thrust', where the mount is angled a few degrees pointing down and to the right respectively, although not necessarily together.
The down thrust limits the plane's natural climbing performance, while right thrust is used to act against the torque generated by the spinning prop.
Which angle and how much totally depends on the model in question and down thrust or right thrust is usually determined in the plane's stages of design.
Many planes don't have either angle and fly perfectly well - again, it all depends on the model.

Mar 13, 2011

Tourque roll motor angle
by: noobyrc

It is very hard to tell if you need to off set any counter action the plane may have. It sucks because you usually do not know what needs to be done until the plane leaves the ground, but usually in those couple of seconds you find out!

I have learned type of motor and battery combo, on top of just when does you motor rotate respectively to your radio stick position matters.

But in general if you have a higher torque motor with a counter clockwise rotation you will need at least 1.5 degrees right angle on the motor to insure stable take off.

I have learned even with a new design to use that angle no matter what. Because if it is to much, it is still not enough to make the plane fly out of control, and if it is not enough I am still able to keep the plane under control, I then bring the plane down and make adjustments accordingly.

As for up or down angle, 1 degree up has been my rule of thumb as well, this insures the plane will take off. In many cases though I have found I have had to adjust elevator to compensate, making me think up angle is not really needed, but to me I would rather make a slight elevator adjustment, as long as I am insured the plane will fly or at least leave the ground so I can figure out any other adjustments.

If you want to test with out flying you can try this:

I did some bench testing at home one day. I took one of my planes and clue 2 wooden dowel rods one on front and one on back. I sat the plane between 2 chairs and put books on the down rods to keep them from off the chairs.

I then fired up the plane motor. I was completely blown away by how hard the planes counter roll in reflect to to the motor rotation. The whole plane actually rotated opposite the motor rotation so hard the plane itself began to spin round and round between the chairs.

This to me was a mythbusters moment,because I really in my mind could not see how angleing the motor would do anything to stop it.

But i did I angled the motor 1.5 degrees to the right or left if your facing your plane directing (like car door, I would best say angling the motor twords the passenger side. using a cheap dallor store angle tool thingy (you know the half round thing, I forgot what its called but I still use it today)

Anyway after angling the motor I redid the experiment, it rotated some, but ti never was able to rotate a complete rotation, it was enough to prove to me putting a angle on the motor did counter torque roll.

Jul 03, 2011

Art Tech P51 D Mustang
by: Casey

Hello, I just got an Art Tech P-51D Mustang, has a 37 in. wingspan and a Dat 700 motor. This plane's motor does not have any built in thrust angle.
I tried to fly this plane before I was real familiar with thrust angle, anyway, when I hand launched the plane it started to roll a bit left, so even though all of the control surfaces are level, it sounds like I need to give it a little bit of right aileron until it levels out?

Jul 04, 2011

Art-Tech P-51
by: Anonymous

Yes, my ParkZone P-51 does the same - a bit of left torque roll when I launch under full power. Just correct it with ailerons as you say.

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