miniTitan Overheating

[Heli_Dan]

Hi,
I am having some overheating issues on my miniTitan. The setup is as follows:
Stock heli built from a kit.
Stock Motor and ESC (using factory default settings)
Using the stock 13T pinion.
3x DS285 Servos
1x JR340G Tail Servo
Logictech 2100T gyro
AirThunder 3s 2200mAH LiPo
Spektrum 6100E receiver
Align Pro 325 wood blades.
Pitch and throttle curves set as per the manual.

I will get about 8 min just hovering around in normal mode. In Idle up 1 about 6 min just doing figure 8s. I have not yet tried Idle up 2.

About 1 min after the flight I would measure the pack voltage and it was never less than 10.1V usually about 10.3v. The trouble is that the battery is hot (but I can hold it for some time) and the motor is scorching hot - can't even touch it for a second.
Already checked the tail belt, lubed the main and tail shafts.

Any other suggestions as to what could be the issue??
Also, would an external BEC help with temps (specifically ESC temp) or duration? If so, which would you recommend?

Thanks in advance.

[daijoubu]

Raise your throttle curve. The one published in the manual is a bit low and runs the ESC and motor in an inefficient region especially if you're just hovering which is very hard on the power system. I run governor at 70% in Normal which seems nice and keeps things cool. I usually pull 1600mAh out of my 2200 packs which leaves me around 11.2v on my chargers display.

I recall having thermal issues with the ESC and once having a shutdown when running the suggested curves.

[Heli_Dan]

Thanks for the reply daijoubu. If I recall, my throttle curve is 0-45-65-85-100 in normal mode, which would at have me at about 70% when hovering at above half stick.

What would be some suggested throttle curves to use if I do not use the governor on the esc?

Am I really pulling too much from the packs? I thought that lipos could safely be discharged to 3v per cell, so that my end voltage of 10.3v total was well within the safe range.

Thanks again.

[daijoubu]

I forgot to check what the stock pitch curves were... They're totally wrong. Set yourself up for -2 at low, 0 at mid and 10/12 at high stick. This will push your hover up to a higher rpm where things will run cooler.

From what I've flown, the governor on the stock ESC is pretty nice. It makes me want to try gov on my TRex 500 despite what everyone says. Give it a try. Also make sure your belt is loose. Gear mesh can also contribute to the load on the motor. Double check that and back it off a bit if it seems tight.

The generally accepted rule for flight times is 80% of the packs capacity (actual if you know it). Not too many people rely on the ESC cutoff. You can fly a lipo very low, but lipo technology prefers a shallow discharge/charge cycle. If you have a charger that displays the mAh put back into the pack, then use a timer to limit your flights. Aim for 80% consumed. Good quality lipos will hold their voltage pretty far into the discharge curve and then just drop off pretty steeply. This is hard on the pack as you can tell by how hot it is.

[Heli_Dan]

Thanks daijoubu, I'll try those pitch settings this weekend.

[Tim Tompkins]

Dan try the 11 tooth gear and set the idle up 1 to 85 across the line. It is much more efficent the higher you set the speed. The smaller 11 tooth gear will keep the headspeed reasonable for your use. The stock motor does run hotter than most others and doesn't seem to mind. TimT

[turkey721]

I also use the stock motor, esc. I use the 11T rhino pinion and my pitch curves are set at -3,0,3,6,9 degrees and the throttle curve is as follows 0,55,85,90,100
I hover around 4 degrees of pitch (quess) and that would put me at about 85%-88% throttle. My head speed is aprox. 2500 rpm and a motor rpm of 35000. I use a 2200mAh and run it to about 75% drain and my flight are around 8min +or-. My motor does get hot, and the esc and battery get warm. I have heard, but have not tried carbon blades. They say they are more efficient than the stock blades. Hope this helps for what its worth. Happy flying.

[daijoubu]

I have a 12 tooth pinion on my bench waiting to go into the MT as well.

[Heli_Dan]

Thanks for all the input guys. I can see that I will be (happily) busy this weekend :) trying the suggestions. I found the assembly portion of the manual very good - this ws my first build, but maybe TT should leave the setup portion to you freakers. :noteworthy

[daijoubu]

I've been wondering this, who writes the setup pages in the manuals? Even Align gives a setup that will hover at mid-stick with a too low headspeed in Normal mode. Is there a different group of pilots that use those settings on the pod and boom helis?

[turkey721]

Those setting are just starting points. To have the heli fly good and right you need to do all the setup first. A mechanically sound bird is a good flying one. I always start out with my servos at a 90 degree with the swash and this is at mid stick. I level my swash at mis stick and then set my pitch from there. This way I get even pitch both positive and neg. in stunt mode and setup for normal also. Watch the finless bob video on pitch and throttle.

[Heli_Dan]

turkey721, I did look at the finless vids, couldn't have done it otherwise. I may have to look at the curves vid again, though.

Over the weekend I did switch the ESC to governor mode. Now I run 0-75-75-75-75 in normal mode. There has been an improvement in the temps, but I think the batt and motor still run too hot. Will try running in Idle 1 (flat 85% curve) and see what difference that makes.

I don't have an 11 tooth pinion available, will look into it though.

Thanks again for all the input.

[turkey721]

I put a small Axi fan on my motor, it fits almost perfect and runs a lot cooler. It is a model 22XX. It cost around $15. It should help your motor run cooler.

[e325]

hi if untherstud ok you have stock esc and motor tyr to install a cooler on esc see this site on cooler tuning , and that solve the esc eating problem, i have same times power cut's and this solve it
helimudelista.hi5.com (http://helimudelista.hi5.com)

[Heli_Dan]

The fan is a good idea turkey721, I will look into purchasing one with my next parts order (seem to be having quite a few of those lately...)

e325, thanks for the esc mod idea. If I understand correctly, you have exposed the heatsink on the esc?? The stock esc that I got did have the heatsink exposed.

I will keep trying - I intend to lube the tail belt, even though it is not tight.

Thanks again guys.