gregg660

My Feedback: (2)

Hello,
Since getting good with a Parkzone cub, I decided to go for an Alfa fw190. The recommended motors..wanted a spare... that I got was a Graupner speed 300 6V and the Power Plant is an 8 cell 1100mah Nimh. Before flying, I wanted to get an estimated run time for battery life. So, as I've done with the cub, I simulated run up and off and on power changes to medium, or less for duration with prop on and buttoned up as in flight. with a timer . Well...she heated up and the motor backed out of the gearbox. The box has no holes for set screw hold down for the motor. I 5 minute epoxied it. Seem to be ok on that problem, but motor lost power. Put second one in after holes cut out of the cowl for flow...and canopy off. Same thing..trying to simulate a flight on the ground killed the motor. So...1. should I try to at least drill one hole for hold down of the motor to the box ??? 2. Is it me doing the test without it getting additional cooling from flight, or is it the more amps used that I have to treat these gently??3. Would I have the same concerns with a brushless set up??, which maybe I should have gone with. Live and learn. Any insight would be appreciated. Ordered two more motors last night, and emailed Alfa and Hobby Lobby with questions.
Gregg

Foamaholic

My Feedback: (1)

8 cells is too much for a 300 can motor. Don't run the motor for long while holding the plane. This will overheat the motor.
If you go brushless you won't regret it. The performance increase is amazing.
I love the Himax 2015/4100 in my 350 powered GWS Beaver. Castle Creations Phoenix 10 (or 25) esc.
They can handle a 10 cell pack. I use 2s and 3s lipos. Get the combo motor/gearbox for about $66. It comes with 3 gear ratios. I use the 5:1 in my Beaver.

Direwolf

By the way, I wouldn't throw the motor away. Often what has happened is the brushes have simply burned up. Brushes can be repaired or replaced in many cases. Even if the coil has broken in one spot, it may be possible to solder it back on. If the coil is too damaged to repair, then you can always remove the coil and wind the armature with new wire. This is easy to do on most motors and I recommend trying it at least once. It takes a long time, but it's good for the soul to know how to rewind a motor by hand as a last resort.

-- Brian

Matt Kirsch

My Feedback: (21)

8 cells too much? Sorry, that's an inaccurate statement in and of itself. Maybe if the prop is too large, and/or the gearing too heavy, 8 cells is too much. I personally would not run a 300 motor on any less than 8 cells. What is the prop size and gear ratio?

What's too much is making extended static runs on the ground, especially with no cooling. The center section of the propeller, where the motor is, moves very little air, especially when the plane is not moving. Without proper cooling, the motor will get very hot very quickly. Part of that is ventillation, and part is the forward motion of the airplane in flight.

Foamaholic

My Feedback: (1)

I was wrong to say 8 cells would always be too much, but in my experience it is.
I've seen 300 motors burn up on 8 cells drawing under 5 amps.
Maybe they were low quality motors.

gregg660

My Feedback: (2)

Thank you all for your responses. I've learned a lot. This seems the place to go for info. It reminds me of the Avsim flight sim forum.
Gregg

Matt Kirsch

My Feedback: (21)

That'sa what'a we like'a to hear