E-flite Park 370 EFLM1000 direct drive?

[JeremyParticipant @jeremy15845]

Some years ago, I scratch built an Orlyonok A90 Ekranoplan, inspired by Ashley Needhams model of the same descibed in Model Boats. I used an E-Flite Park 370 EFLM1010 3600Kv brushless motor driving a 5.7×3 prop. This motor burned out some time ago and I would like to replace it.

I can get the similar EFLM 1000 4100Kv motor which, as with the earlier one, is supplied with pinions for linking it to a gearbox. Is this always how it should be used or can it be safely used with a direct drive? I have a 20 amp ESC and a 3 cell Lipo with a 25-50C discharge. When I first used the model, I had an 8 cell NiMh pack which I replaced with the Lipo because it was much lighter. Maybe that is why the motor then failed.

£37 is a lot to pay for a new motor but I would like to be reassured that the same fate does not await it! Expert advice would be much appreciated.

[JeremyParticipant @jeremy15845]

[Dave MilbournParticipant @davemilbourn48782]

Jeremy
This motor is advertised as being suitable for running a 9×6 – 12×6 aircraft prop via either a 6.6:1 or 5.33:1 gearbox, hence the pinion which is fitted. Direct drive of a smaller airscrew will almost certainly overload and burn one out. We're back to my favourite comparison of fitting a Ferrari V12 into a quarry truck i.e. power and speed aren't necessarily the same. I believe you would be better looking for an outrunner type, which have higher torque at much lower revs. Ashley may be able to point the way here.

Dave M

Edited By Dave Milbourn on 04/09/2018 14:21:42

[ashley needhamParticipant @ashleyneedham69188]

Component shop seem to do a Leopard Inrunner 20X40mm 2600Kv for twenty quid, on 3s should be ok.
I have used my park on 3s and it goes really well. The thing is to have as fine a pitch prop as poss, both for low speed thrust (low boat speed that is) and enabling the engine to rev without being overloaded. I think the use of a wattmeter may be in order to ensure you don't overdo things.

Ashley

[JeremyParticipant @jeremy15845]

Ashley, your recommended Leopard looks a good fit for the existing Park mount.. Is my 7.5×3 prop a fine enough pitch? If not, what pitch should I look for with a prop of the same diameter? I will test with a wattmeter. Jeremy

[ashley needhamParticipant @ashleyneedham69188]

Jeremy. There is no easy answer to this…I have a tray full of small props at home.

My prop is only 5.5×3 (5 1/2 inches diameter) and I would try something this size If I were you. Something in the range 5-6 inches at pitches of 3-5. JUST possibly the 7.5 was a bit big for the motor, as Dave says, this type f motor is really for a geared unit, however the spec does say ok to use small props.

I used a small diameter motor in order to preserve the look of the Ecranoplan. I made the foam flyer with a speed 480 motor driving a 6 inch prop and on its 2600Kv and 7.2V|Nimh battery it went quite well, but I was not so concerned with the small diameter on top of the tail for this one.

Ashley

[JeremyParticipant @jeremy15845]

Ashley, I made a typo. My prop is 5.7 not 7.5, so I will go with that and the Leopard. Thanks for the advice. Jeremy

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