Vibrations = short flight?

Hi Wan;

I've often thought that myself: energy used in causing the motor to vibrate can't be spent making the plane fly, so you'd have to keep the throttle higher to get the same flight performance, or experience shorter flights.

When you say the "motor mount" broke, you don't mean part of the actual motor casing, do you? I would think that that would be a warranty item. But, if by "motor mount" you do mean the part the motor is fastened to, then no, I couldn't see going back to Hobby Lobby for that.

I think the best way to eliminate the vibration is to balance the prop. And of course, fix the broken mounting.

Perhaps the shorter flights are an indicator in the battery's condition, too. Maybe review how you're charging it.

Also consider this: I had a nose-on landing on mine that popped the small E-Clip out of its groove in the motor shaft. When I pushed it back in place, I think I actually pushed it too far, beyond the groove on the other side, and made the motor draggy. Inspect that clip, make sure it's seated properly, and the motor turns freely, and maybe oil the shaft in that area. Also (since it's a "rotating can" motor), make sure nothing is brushing up against the motor.

Dan.

I have experienced this directly with a 480 Permax mounted on an airboat. The prop was slightly out of balance so it buzzed a bit at full throttle. If I grabbed the pylon where the motor was mounted and damped out the vibrations, the motor actually sped up (I used a tach). I was cureous about this so I hooked up an ammeter and the current went down when I damped the vibration. It wasn't much, about 200ma, but that could be significant on some setups.

I doubtt hat the motor itself is the source of the vibration. More likely an out of balance prop or spinner. Remove the prop and spinner and SLOWLY increase the speed of the motor and see if any large vibrations occur.

I had something similar happen, with similar results. I normally get 7 minute flights with my goldberg eagle 2. After take off the other day it started making a buzzing sound. Since I was in the middle of a funfly event, I didn't want to bring it in. However it lost power a lot sooner, it was pretty much dead at 5 minutes. When I did land I found out that the plastic spinner had popped out on once side making it unbalanced. So I'm assuming that the vibrations must have ate more power as if it was spinning a larger less efficient prop.

Yes. A fully balanced prop is quiter, and revs higher for the same current. More power to the prop, less to the audible vibrations :)

I read all of your commentaries and I appreciated them. Tomorrow will be a fine day for flying. The batteries are the same ones that have used over a hundred times on another plane with the same type motor.

I have done just about everything you suggested (ran the motor without the prop, repaired/replaced the motor mount, checked the balance of prop and spinner, etc). I will put those ideas to test.

I will report back about the results.

Thanks, Wan

Well, I'm back. Actually I went flying last Sunday. I flew the plane only once because of gusty winds and no one was at the field. The last time I flew, there were at least 6 club members there and one helped find my plane in the cornfield.

As might have been expected, the repair and prop balancing allowed the normal flight time, about 7 minute.

Wan

Well, I'm back. Actually I went flying last Sunday. I flew the plane only once because of gusty winds and no one was at the field. The last time I flew, there were at least 6 club members there and one helped find my plane in the cornfield.

As might have been expected, the repair and prop balancing allowed the normal flight time, about 7 minute.

Wan