Topgun Mirage 90mm, motor cuts out.

[MrFoo]

Hello, I'm wondering if anyone could help me identify a problem I'm having with a new Topgun 90mm Mirage. I've had 3 flights and each time I've had to dead stick land after the motor seem to cut out. I'm using a Typhoon inrunner and a 75 amp Masterspin (Hacker) esc. The battery is a 40c 6 cell.
The motor is rated for 6S, I checked that. It's a good quality motor.

It may either be the motor or the esc overheating, I'm not sure. It flys well for a few circuits, fan is balanced, sounds great. I do a few fast passes, all looks good. After a minute or two, I get the cutout and luckily its happened on the downwind part of the circuit so I could bring it around to land.

Does this sound familiar to anyone? Do I need a higher rated esc?

[Sir Crash-A-Lot]

What is the capacity of the battery? I had a 5000mAh battery in the L-39 and it was only good for a 6 minute flight. If you are using a smaller battery you will get a lot less run time.

Mike

[MrFoo]

The battery is 4000 mAh, but it only took out 1000 mAh during the flights so I discounted a low battery level.

[CHELLIE]

Originally Posted by MrFoo

Hello, I'm wondering if anyone could help me identify a problem I'm having with a new Topgun 90mm Mirage. I've had 3 flights and each time I've had to dead stick land after the motor seem to cut out. I'm using a Typhoon inrunner and a 75 amp Masterspin (Hacker) esc. The battery is a 40c 6 cell.
The motor is rated for 6S, I checked that. It's a good quality motor.

It may either be the motor or the esc overheating, I'm not sure. It flys well for a few circuits, fan is balanced, sounds great. I do a few fast passes, all looks good. After a minute or two, I get the cutout and luckily its happened on the downwind part of the circuit so I could bring it around to land.

Does this sound familiar to anyone? Do I need a higher rated esc?

check to see what the LVC is set at on the esc, Low Voltage Cutoff, also, is the ESC hot after you land it, Chances are that your ESC is not big enough, and you may need to use a 100 AMP esc for an Electrical Cushion, also, check to see that you are getting enough air flow through the jet to cool the electronics, ESC, receiver and lipo. if you have a Wattmeter, check the amp Draw at WOT, If you dont have a Wattmeter, get one soon it will save your investment, hope that helps, Chellie

[CHELLIE]

Also check all of your connections, make sure they are tight, esc to motor & esc to battery, pull on them to see if the solder conection is good, hope that helps, Chellie

[Sir Crash-A-Lot]

K, few more questions then. How old is the battery and what kv is the motor?

Mike

[MrFoo]

The lipos Im using are brand new, the kv I'm not sure. Just to be sure I bought a new 99 amp hacker esc, so I'll install that and see if it helps.

I did have some problems with the motor timing earlier, so it had been 'polling' on start up. I hope I didn't damage the motor.

[4stripes]

If you have the old style THG fan it draws a lot of AMP's and is probably too much load for a 75A ESC (very similar to a Hoaye fan). The newer style HTG fan is less aggressive and would likely draw close to 75A with a fully charged battery. Is your ESC in the cooling airflow of the intake or exhaust?
Change the fan to a Freewing 90mm and it will likely run fine.

[ExtremeRC]

Funny no one has asked the obvious question, Which Motor!?? And which Fan??

HET makes a myriad of motors, we need to know which motor you are running and in which version of the fan, photo of fan if you are not sure.

If its a 600-37-2 then it pulls barely 55A on 6 cells with the wemotec Midi rotor, around 65-70A with the old Haoye 7 blade rotor, the ESC should not have an issue, if its a 600-32 then its not really made for 6s and will be pulling 70+ amps.
If you are using HK batteries then the pack could well be sagging out under load and hitting LVC, this is the most common issue especially in cold weather. HK batteries are not made equal to premium cells, there is more chance of getting a bad pack or a weak cell or two, and their chemistry generally is not on par with the premium cells so when put under a heavy EDF load they often sag out.

If your LVC is set high and to hard cutoff then it will cut, did you try pulling the stick back and starting her up again? If its hitting cutoff you should be able to restart the motor at reduced throttle.

You also need to get a meter onto it and check the amp draw and post it up along with the motor and fan type. Other issues can be from motor bolts being too long and touching the windings, this causes a short and jump in amp draw which could cause the ESC to thermally shut down and if unlucky the motor to cook.