Compare OS 30 4Stroke with electric motor

[Bernard Chiswell]

I have a small Taylorcraft which was powered by an OS30 4stroke. This was not powerful enough. Which electric outrunner can install which is more powerful than the OS? I have a 4Max PO-2380_1210, would this be OK?

[gangster]

My guess is that that motor might be a bit low on power too. Suggest you ring BRC hobbies for recommendation. I have used the eMac motors that they sell and am very happy. Advise them of size and weight of model and they will avail you of their expert advice

[michael cawood]

Bernard are you sure that is the number on the motor. its more likely PO-2830 1210Kv which is about 200 - 220 watts so I don't think it would be an improvement on your OS30 mike

[Trevor Crook]

Bernard, I had a quick look on the 4-max website and couldn't find that motor. In their nomenclature, the 1210 is the kv, or revs per volt.

You don't give any details of the model, but if a .30 isn't enough, I'm guessing it weighs 4-5 lb, so you will need a setup that provides around 400W or so. A ball park guestimate would be a suitably rated motor around 900 -1000kv, with a 3s 2500-3000mAh battery and 40A esc. This should be about right for turning an 11x6 or 11x7 prop. All this is from my previous experience, not using any calculators.

If you can provide any further details of the model, I'm sure plenty of others will chip in. I didn't give the obvious response of "use a .40 instead" because that wasn't what you asked!

[gangster]

Well spotted Michael. I had automatically read it as 2830. It's got to be that not 2380

[gangster]

An emax 2820 07 will give you about 400 watts on 3s and if that is still to low it will happily give 600 plus on a 4s

[Bernard Chiswell]

Thanks to all you good guys for your help. Much appreciated!

[Denis Watkins]

I have a saito 40 on the Tailorcraft Bernard, and it has power in reserve, but my SC30 was marginal.

The calculations suggest a 30 would fly it

But with the struts on and the beautiful spats, I guess the drag is too much

The manual recommends the 

E-flite Power 25 BL motor 870kv,

Edited By Denis Watkins on 03/08/2017 16:57:04

[Allan Bennett]

For my first ever electric conversion I simply got a motor that could generate as much power as the OS48FS that was in it.  Can't remember the exact OS data -- I think they quoted 0.75hp, so I multiplied that by 746 to get watts.  Electric motors weigh less than their glow equivalent, so you can always add a bit for luck.

You need to be sure you get an appropriate kV too, so that it will swing a suitable size prop with whatever battery voltage you use.  The motor manufacturer will give you a guide to what prop is appropriate, but you should always use a wattmeter to check actual amps for your particular setup.