Burning up main motor

[tjrtmaster]

I have a HB CP2 that I have converted to my Futaba 9C tx. After about 10 flights I am burning up the main motor. This has happened several times.
I have 0 - 10 degrees of pitch in normal mode and -10 - +10 in idle up. I fly in normal mode most of the time.
Anyone have some input on this problem?

Thanks,

Tim

[Rick Rotorhead]

Firstly, are you using a heat sink, that may help. Secondly, if its only been a problem with the 9c then maybe the PT curves used by your 9c setup are overloading the motor - try reducing the pitch range a bit so the motor works less hard. The stock motor is a bit feeble; too many burts of +10 pitch will certainly draw the current and heat thing up. Do the cells get hot? What about the head speed, does it sound different with the 9c than with the stock Tx?

[tjrtmaster]

Rick,
I have 2 heat sinks on the motor. I have been using the 9C for a while now so I am not sure about the differences with the stock tx. I am going to try lowering the pitch and see if that helps. I am using TP 1320's and they are just warm after flying.

Tim

[Skiddz]

Check your gear mesh.. Too tight will make the motor work hard. Definitely double check your pitch settings (mechanically and in the Tx) to make sure nothing has changed.

I also run a 9C on my BCP, but I'm running brushless and never ran the stock motor with this Tx..

[zooland1]

Rick,
I have 2 heat sinks on the motor. I have been using the 9C for a while now so I am not sure about the differences with the stock tx. I am going to try lowering the pitch and see if that helps. I am using TP 1320's and they are just warm after flying.

Tim
By 1320's do you mean 2s or 3s. If 3s, what pinion motor? Should be 8t. You're in the correct pitch range, so that doesn't sound like the problem to me. Did you set an endpoint for the throttle? Otherwise you can continue throwing higher amp input after you've reached the limit of the speed contorl. You want the red light on the 4-in-1 coming on about 80-85%. The endpoint on my 7c is 37%.

[ronaldf]

I have just set up my 7CHP for use with my HB CP2. I have the throttle curve set so at full throttle/pitch the led stays green. Should it be set to make the led go red at full throttle? As of now the throttle curve is set at 66. When set at 66.5 it flashes red, at 67 it is steady red. This is with just a bare head, no fly bar or blade assemblies.

[akshaw]

From what I understand at the point at which application of throttle (by moving the throttle stick up) changes the light from green to red, you've maxed out the motor speed and any further application of throttle won't increase motor spead. What you want is to hit that point when the throttle stick is pushed very close to all the way up.

To achieve this, you can do as Ronaldf did. But be very careful to first have the heli secured, main blades removed, tail motor disabled and paddles sufficiently away from hitting anything (better yet, remove the flybar). With the heli on and throttle stick pushed all the way up, if you and dial the end of the throttle curve down from 100% to the point where the light changes from red to green, then about 5% above that point would be the ideal place to set the end of the throttle curve. (When the light changes to green, you'll actually hear a decrease in motor speed if you keep dialing down.) Ronaldf, I think what you have it set to is fine. If you wanted to you could take the end of your throttle curve up to 71.5%.

[ronaldf]

Thank you akshaw,

I think I will raise the settings. The led turning red will indicate that battery is low (more throttle to get same flight characteristics).

[zooland1]

If you look at how the stock Tx works, you hit the red signal at about 85%. From what I read a while back, you find the point where it turns red right at full throttle, then add five percent tto that. Mine turns red at 32%, so my final setting is 37. According to Horizon, it's not a problem to have the 4-in-1 in the red. It just indicates where the power maxes out with a little cushion. You just don't want it going red at mid-stick, which is what it will do if no endpoint is set.

Another thing to look at is the pitch settings in normal mode. If you don't adjust the pitch endpoint you'll have a lot of negative pitch at zero throttle. The stock Tx is programmed to adjust for this. Your normal curve will start somewhere around 40% (wherever you hit -1 or zero degrees pitch). The tricky part is getting idle up and normal to match at hover speed. On the 7C this would be step 3, I think the 9c has a seven step curve so it would be step 4. Make sure you put the steps in between linear from whatever step 1 and step 3 end up (7C). For instance if step 1 is 40% and step 3 is 58%, then step 2 is 49%. Oh yeah, unplug the motors first. How I found mine is to put it roughly at hover in idle up, then flip to normal and adjust the step 3 curve until they match. The reason I suggest this is if you haven't adjusted this curve, when you're on the ground you're literally driving the heli into the ground, which in turn I think could burn out a motor.

To better explain all this, just in case I screwed it up. Watch Finless' vids on pitch and throttle curves for the Trex. The settings are pretty much the same for the blade. He also has a vid specifically on how to program the 9C.

[tjrtmaster]

Thanks for all of the input. The red led on the 4-in-one was comming on at about half stick. I was using 100% ATV (throttle) on my 9C. The first thing I did was to make sure that I had -10 to +10 degrees of pitch. Then I decreased the ATV on the throttle channel with the motor at full throttle until the red light went green which was 32%. I increased it to 37% and hopefully my problem is solved.
thanks again.

Tim

[Gary JP4]

I think you are getting good advice but just to clarify for folks learning from this. The red light comes on with throttle position regardless of load. It comes on at the same position even if the motor is disconnected. It does not indicate load or battery condition. I think ronaldf is saying the battery is low when the red light comes on because the throttle is at a higher position, probably hovering. There is a common misconception though that the light indicates overload.

Some folks feel the stock motor is not capable of pulling 10 degrees of pitch and limit pitch to something like 8 degrees with 100% throttle. This puts less load on the motor and they claim cooler running and better performance. I have the stock Tx and mine went to +/- 12 degrees or more. I moved the linkages in one hole on the servos. I can't remember how I left it (will check when I get back to it). I think I ended up with + 10 and let some extra pitch run out on the negative since I don’t 3d (negative is more than –10 degrees). Mine bogs down a little at full throttle held in my hand. I have the HB CP2. Since you have a good Tx you should try limiting pitch like you said. I don't think you said if it bogs down or not.

Both my motors get very hot. I have 2 heat sinks and thermal past on the main and GWS DD with GWS large heat sink on the tail. I would like to try less pitch but haven't taken the time to set it down further mechanically. My good radio on a Trex is a Spectrumized JR 6102 so I will have to hack an Rx into the 4 in1 to use it on by HB CP2. I think I will do it eventually.