I copied this from the Neu website. Basically its warning of weaker bearings in the H motors the way I read it. Are they smaller bearings to accommodate the fan or something. Anyway I would think that if the load a heli puts on the bearings is questionable, then I would for sure think the applications we are using these motors for would be a problem.
Anyone know anything about this?
http://www.neumotors.com/20061222/HeliMotors.html
(scroll to the bottom of the page)
Note for heli motors! Be sure that you check the motor bearings for noise every few flights. Excessive side loads on the front shaft can damage the bearings which can lead to bearing failure. Be sure to double check gear mesh and make sure it is not too tight! If there is noticeable play in the bearings they are making noise then it is time to have the motor checked! Damage of this type may not be covered as a warranty! Use your ears and avoid problems. This is most important for the 3D type fliers!