NTM Motor

[CJD]

Would a NTM Turnigy 42 prop drive 42-48 650k be suitable for a Multiplex Mentor

Cheers

[john stones 1 - Moderator]

Lot depends on whether 4cell or 5cell lipo and prop used, but that motor's rated at 1295watt max so I would say much to powerful for a 2kg model, if you want to fly as trainer look for something 600-700watt ish.

John

[CJD]

Thanks John for reply,I don't want it as a trainer,as I have gone slightly behond a trainer,but I just love the model,and on a nice summers night it's fantastic,it's just that I have that spare motor and I didn't want to buy a new one if that one would do the job

Colin

[john stones 1 - Moderator]

Big variety in choice in the SK3 range at hobby king and not a lot of money CJD

John

[CJD]

Many thanks John

[Dave Hopkin]

The actual delivered power can be hugely varied by a) the number of cells and b) the prop

fully lipo'd and prop'ed to the max it might deliver 1295W but cut it down to 4S and a smaller prop and you can tune it down to something more appropriate

[CJD]

Thanks Dave, what prop would you suggest ?

Cheers

[Dave Hopkin]

I would start off by looking at what set up is recommended for the Mentor - so I know what would be an initial target wattage - and just as important compare the Kv ratings of the two motors, if the recommended set up has a faster Kv then you would need to increase the prop load to compensate

[MattyB]

Short answer is probably not - the stock motor is a 35mm class 1000Kv motor of about 200g designed for 3S, and yours is a 42mm 650Kv of >250g designed for 4-5S (though I would take their rated power of 1300W with a very large grain of salt; that's >5W/g, far more than the 3W/g rule of thumb generally used for cheap motors). You are far better choosing something in the 35mm class for ease of fitting and getting the CG right, though tbh I would be thinking about a different airframe if you have moved beyond the trainer stage - a Mentor is a fine machine, but it's no precision aerobat.

Edited By MattyB on 09/05/2016 01:33:21

[MattyB]

This Turnigy SK3 3548 is probably a good drop in replacement at a much more affordable price than the stock Mpx motor...

Edited By MattyB on 09/05/2016 01:38:34

[onetenor]

|He's already got his motor don't forget

[Tony Bennett]

just stick it in and fly round on half throttle.

[CJD]

Thanks all for your input, possibly have a go with a 3548

[CJD]

Well you would not believe it, but I have found a brand new skf 4240 740kv 870 watts would I get away with that on a

Mentor,didn't know I had this motor.

Cheers

[john stones 1 - Moderator]

Yes 4 cell or 5 cell ?

[CJD]

Thanks for your reply John

[MattyB]

It is better than your original suggestion - about the same weight as the OEM motor, and with that Kv it should be be possible to prop it to ensure good performance and duration. You may still have issues fitting in a 42mm motor vs. the 35mm the Mentor is designed for though.

Edited By MattyB on 11/05/2016 17:06:14

[CJD]

Thanks matty