thesenator

I should say I'm a beginner and only been flying about a week!.I've been teaching myself to fly so far(don't have a car and the nearest club is a bit of a long walk away) with pretty good results.Caught my first thermal today!(had to stick that in very happy with myself).

I have an alpha 180 motor glider(about 2m) running a the stock 540 motor with a jeti 350 esc and 7 cell 2000 batteries.
Problem is the motor started to smoke today.I was hoping someone could help me get to the bottom of the problem.The motor got quite hot as did the battery connections and the battery itself was warm after only a short run.The motor cuts out after only a few seconds on full throttle even on reasonably charged batteries.Ordered a speed 600 race motor two days ago before this one got sick and I don't want to kill that one too.please help.
Here are a few possible reasons

I've had a few hard landing/crashes one in particular cracked the spinner and bent the spinner screw pretty badly.The motor has been making a ticking sound and generally not sounding the may west

Got a new spinner but had to get a prop and adapter aswell(not sold separately).The propeller set is a Ripmax for a Nebula/Sirius.The new prop is smaller than the stock prop but decided to stick it on and see how it flew(the Alpha seems under powered hence the speed 600 order was willing to give it a try to see if it helped).

I didn't run in the motor when i got it.I wasn't aware of such things at the time.

Matt Kirsch

My Feedback: (21)

It's not absolutely critical that you run-in the motor before using it. The motor will perform a bit better if you do, but not running it in would not cause it to start smoking.

The motor got bashed hard enough to bend the prop adapter, and it started to make a ticking noise. It has since started to smoke. Frankly, I don't think any further investigation is necessary. If the plane hit hard enough to bend the prop adapter, it certainly bent the motor shaft as well. I don't think you did anything specific, other than crash, and I don't think anything is critically wrong.

When you get your new motor, be careful. The Speed 600 Race is a much "hotter" motor than a standard 540/Speed 600 (same motor IIRC). Given the same battery and propeller, the motor will spin faster and draw more current (Amps) than the 540 motor. You have to make sure that you're not drawing too many Amps, exceeding the capacity of the ESC and/or the motor. If you do, you'll be seeing more smoke.

From what you say, though, the new replacement prop is smaller than the original. That will compensate somewhat for the new hotter motor by putting a smaller load on it. It will spin somewhat faster than the original motor, so that should more than make up for the smaller diameter.

To properly figure out if the motor can handle the current you're going to put to it, you really need to tell us the size of the prop, diameter X pitch.

If someone doesn't respond with a yay or nay, or outright tell you how many Amps that setup should draw, you'll have to be REALLY careful. Fly the plane, land, and make sure the motor, battery and ESC aren't exceptionally hot.

thesenator

Hi ya Matt thanks again for your speedy reply.
My new motor just arrived thankfully so i can fly this weekend!.
The spec of the old stock prop that came with the plane was 8x4 slim(according to the manual), the new prop that i was running and will fit with the new motor has the same diameter 8cm and pitch,but it is thinner and lighter and is about 25% less wide form top to bottom when looking straight on.not sure if this helps you any?.

Also.
The info that came with the Speed 600 race says running-in is not necessary does that sound right?

And one more thing.
Got a new battery pack i assume it's best to trickle charge batteries for the first charge?

Thanks Matt.

MTEXX

thesenator-

I had an experience with "smoking" a Speed 400 motor. The experiment was to change from a 5x5 prop to a 8x6 prop. At WOT, I smoked the motor within 2 minutes. PS: the test platform was a zagi 400X 48" flying wing.

When you increase pitch (and less importantly) increase diameter, then you increase load on the motor.

When you increase load on an electric motor, you will see an increase in current.

When the current exceeds the motor's capability, it may heat to the point that the coils' insulation burns up and will then cause a short which can vaporize adjunct material.

As far as hot batteries and hot motor; that is a day in the life of eFlight. Use multiple batts. Keep a spare motor wired up for a really rainy day.

As far as your bent shaft; I agree with Matt Kirsch; chuck it. In the meantime, learn crash management skills =D

You have a few solutions:
1) less pitch
2) less diameter
3) astute throttle management
4) higher-current motor
---which entails higher current ESC and batts...
5) investigate brushless motors/ESC ($~200)

MTEXX

thesenator-

Oh and one more thing-

GET YER KEISTER TO THE RC CLUB!

Even if you are not a member or even not AMA, they will prolly be very willing to guide you. Besides, the free airshow is really cool!

thesenator

Thanks a million for your replies!.
Seemed to be having some good results with the new motor and a slightly smaller prop.
That was until today.
Wings Snapped in two mid-flight!.just started to pull up to do a stall and they folded,wasn't even going that fast!.
Thats the end off that and the motor.All else seems ok.So it's a new plane for me!.

The local shop has an Irvine Earlybird.Think it's pretty close to what I had.
Might drop in and get it tomorrow.
Although I may hold off and get something with ailerons(just rudder and elevators so far).

Any suggestions would be appreciated.

Thanks again