STOL mk2

[Dave Hess]

It's the plan from the old Aeromedeller Plans Handbook. I built an airframe about 20 years ago, but never got as far as covering it or doing any installation apart from the OS 25 FSR motor. I now want to finish it and convert it to electric, but I don't know much about which components are available nor what I should use.

Could someone advise me which motor, propeller, ESC and battery to use.

The STOL mk 2 has a lot of carrying capacity, so I guess it can manage a fairly large battery, but I don't want it to fly like a brick. I would prefer performance on the side of sportier rather than sedate.

[Ace]

Have a look at working out a power train on 4-Max as an excellent starting point.

**LINK**

You could also look at customers models for anything similar.

[Denis Watkins]

Motor in photo here under STOL Mk2

**LINK**

[kc]

It's very interesting that you built a model from the old plan because if you look at the various STOL threads you will see that people who bought a recent plan said the wingspan was more than the quoted 48 inches ( they said 55 inches I think ) Nobody had a plan that was 48 inch span!

So what is the span of yours? Of course this makes a difference ( possibly) to the size of electric motor needed.

[Nigel R]

25 two stroke says to me you want around 350 - 400W in your electric setup.

My go-to choice for that size is:

4S 2200 lipo - https://hobbyking.com/en_us/zippy-flightmax-2200mah-4s1p-40c.html

3536-900kv motor - https://hobbyking.com/en_us/turnigy-d3536-9-910kv-brushless-outrunner-motor.html

On a 10x4 or 9x6 prop the above will replace a .20 glow quite happily. I am using that exact setup regularly on a fairly slow 3lb trainer type. On that prop it only needs a 30A ESC. This is probably not so different to the STOL. On that model I get 10 minute duration and still have 30% charge left in the lipo.

30A ESC https://hobbyking.com/en_us/turnigy-plush-30amp-speed-controller.html

On a 10x5 prop it will be quite close to a .25. I would use a 40A ESC at this point.

It will also go to a 10x6 if needed (40A ESC again).

A 3S 3000 lipo would also work well too, but I have no existing setups I can tell you of.

I would guess at

3536-1000kv motor

11x5 or 11x6 prop

40A ESC minimum, maybe larger?

Perhaps some kind soul can confirm my guess or suggest a proven setup for 3S

Hope that helps

[Frank Skilbeck]

Something like a Turnigy SK 3530-1000 kv would draw 39amps, 410 watts, on a 3200 mah 3s with a 12 x 6 prop, just over 2kg static thrust according to drivecalc .

[Dave Hess]

Thanks guys. That's exactly the sort of info that I was hoping for.

[Gordon Tarling]

Not much wrong with Nigel's recommendations above, except that I'd recommend a 3S 2200mAh lipo and maybe change prop or motor accordingly. A 40 Amp ESC should be plenty.

Reminds me that I really should dig out my 'mothballed' STOL and get it flying again. It last flew on a geared Astro 05 motor and an 8 cell Nicad pack!