Soft mounting motors on Quads

I can see the benefits of soft mounting motors, in terms of isolating vibrations from the flight controller. However, just adding a few layers of tape between the motor and arms is going to do feck all. Think about how the motor is held on to the arm. Screws go through the back of the arm, and into the motor casing, to clamp the motor to the arm. Putting some tape in the mix there does not isolate the direct connection between the motor and the back side of the arm.

To do it properly, you would need some vibration absorbing material on BOTH sides of the arm, thus allowing the motor to move ever so slightly under vibrations.

The second issue, is that the transmission of vibration through to the arm is going to be massively dependant on the vibration spectrum that is coming from the motor/prop combo. The speed of the props varies massively during a flight, so the vibration spectrum is also going to be all over the place. Unless that tape is a super magic material, it is not going to absorb a wide range of frequencies, especially when clamped (tightly!) between a motor and an essentially rigid CF arm.

IMHO, it is better to ensure your props are as well balanced as possible, the motors are as well balanced as possible, and rigid mount everything. Any vibration issues should then be dealt with by soft mounting the sensors on the flight controller (or dealing with the vibrations by using electronic or software filtering).

I'm surprised people haven't started dynamically balancing motor/prop combos yet. Like how you would balance a car wheel with a tyre mounted on it....

And yes, I'm supposed to be working, and yes, it is boring!

Andy

Agree as ballance props are loads better and I do this for my phantom. Also I am not sure on the tape but have done it with my racing quads as I see no harm. I think o rings under the motor and the other side of the screws may work better, however like you say wouldn't arrest all the harmonic issues. It's always best to solve a problem at the heart and from there work back fine tuning.

Anything you do is redundent the first flight you hit somthing anyway.

Mark Barnes wrote:Anything you do is redundent the first flight you hit somthing anyway.

Thats true

Ha ha, bang on that!