***__ The 1/8 Onroad Think-tank __***

[samwong]

Originally Posted by Countryhick

Looks great!!! I think you might want a better quality motor. Maybe try a NEU??
Well done!!

Cheers Andrew

Thanks .. Andrew..

yes exactly ... I really need a serious motor... but in Hong Kong, it is hardly to find....finally yesteraday I got Losi Xcelorin 2100kv for my second trial.

And I will still keep the gear 19T p / 45T s and see how will the temperature of motor be...

May I know your motor spec (kv) and temperature after a continuous run? and how you compare 2gears system vs single gear system in 960 brushless conversion...in terms of motor temperature, acceleration and run time? as I still unsure if it need 2gears system for brushless... to achieve a comparable speed with other Gas Power 960. But seems now just use 2nd gear gives motor too much loading and temperature...( at least with cheap motor, hope Losi 2100kv works better)

Originally Posted by samwong

Thanks .. Andrew..

yes exactly ... I really need a serious motor... but in Hong Kong, it is hardly to find....finally yesteraday I got Losi Xcelorin 2100kv for my second trial.

And I will still keep the gear 19T p / 45T s and see how will the temperature of motor be...

May I know your motor spec (kv) and temperature after a continuous run? and how you compare 2gears system vs single gear system in 960 brushless conversion...in terms of motor temperature, acceleration and run time? as I still unsure if it need 2gears system for brushless... to achieve a comparable speed with other Gas Power 960. But seems now just use 2nd gear gives motor too much loading and temperature...( at least with cheap motor, hope Losi 2100kv works better)

I'm using a NEU 1512 2050Kv. (but I run 6s LiPo) I think your motor KV will be a little low to achieve the same speed as a gas 1/8th, unless you can drastically gear up, which will possibly add to your overheating issues.

Because I use a large aluminum motor mount, the chassis of the car dissipates a lot of heat (this is how the gas motors also dissipate their heat) running temps are around 70deg C. (30deg ambient) This reading is after continuous running on the racetrack for 10 Mins. I see you have a CF motor mount and this could partly be some of your problem.

After running the car with a 2 speed, I don't feel that there are really any benefits. If there was a larger ratio change between first and second then there maybe an advantage.

Because I haven't tested with a single speed I can't definitively state if the run time is better or worse. I do however think there wouldn't be much difference.

Keep us posted!! It's great to see these 1/8 onroad cars popping up

Cheers Andrew

From Red RC

A 2 speed with no mechanical brake? I'm assuming its not completed yet.

[mabu]

Originally Posted by B4maz

From Red RC

A 2 speed with no mechanical brake? I'm assuming its not completed yet.

The conversions looks nice, but i also assume that's it is not finished yet ...

[samwong]

Thanks for your data sharing...

Regarding the temperature problem in motor.... I have some thing not certain...

1. Given other things the same, Higher voltage 6S gives same MOTOR operating temperature as 4S. My thinking...

As either 6S or 4S, the motor rotating force depends on the current on the wiring of motor, and the more current through the wire, the heat will be in proportion. So the heat of motor should relate to Current from ESC, but not related to the voltage of Lipo.

So 6S or 4S will be the same for the Motor Heat issue.
Please correct me.. if I am wrong.

2. The faster the acceleration, the higher the temperature.

As force required is larger for higher acceleration, so current or heat are also larger.

If I adjust the driving style a bit, softer acceleration, that can help the motor heat problem. As currently the acceleration is like a rocket... faster than a 1/12th pan car ..... too much for me.. and others..


3. Braking also gives additional temperature rise.

Heavy and frequent brake ... can make motor suffered additionally.


I will have another trial run with Losi 2100kv ( Diameter is 39mm, maybe torque will be larger ) , 4S and 44T/19T and see the result.