Scale Soaring UK

Gents and ladies,

Just thought I’d share some pics of my installation, hardest job was removing all the lead shot and timber work!

Ell

Elliot,
What prop and batteries will you be using? I imagine you will have about 1000W available, so what do you expect the final weight of the model to be and will you have to sacrifice cockpit detail to fit everything in?

Cockpit detail should be unaffected, about 2kw on tap with a 14x10.

Took a lot of lead out so batteries and motor shouldn’t add much weight if any.

Just to keep that in context. My first tug was a piper cub with a Z38 motor, 2.2Hp, so 1700 watts.

The cub weighed at least 20 Lbs, and would tow up 20Lb gliders, so 40 Lbs, plus two air frames. 42 Watts per Lb.

So I guess you will have just about enough power there Elliot.



BC

Thanks Barry,

To be honest, it's probably closer to 1500 watts with the 14x10, I think 16x10 pulls nearer the 2kw.

It's a really lightly built model, I will weigh it properly this week when I balance it, get my lipos in the right place, but I'm sure it's around the 10-12Kg mark.

Very excited about the prospect of thermal soaring from a flat field without a tug.

Here's a picture of the bodge I used to make the fuz meet the spinner correctly, a bit of PTFE with sandpaper attached, run up on the motor and pressed gently into the rough cut nose. The spinner is not a perfect fit, but good enough, the fuz is ever so slightly ovoid still - despite my best attempts.

Ell.

nearly there...

Are you trying to give Brian a heart attack??

When you have painted the prop white, it will hardly show.



BC

I was going to see if I broke it before I painted it Baz

Re-maiden went really well yesterday, flew perfectly straight away, first taxi trial turned into a flight...

Really, really happy with the model now, just a bug with the ESC to iron out and we're golden!

Big thanks to Jared for filming, as I forgot.

Oh, and for the record, 12.7Kg and around 2.4Kw, so about 85w/lb meant she leapt into the air.

Ell.

Hi Elliot, I believe this to be your first scale model fitted with a motor up front that can R.O.C ?
Can you share with us your feeling as you took that first take off flight and your thoughts on scale models with motors now you have experienced the independence they give.
I believe there are a lot of modelers out there who would like to follow suit but are wary of the unknown.
Also do you now think that you would have intimidated other flyers on the day.
I am sure that your thoughts would be appreciated. Ter.

Hi Terry, good to know someone is watching!

This is actually my second conversion, but the first that will ROG. I love big scalies, but not knowing anyone locally with a tug bigger than 60cc, it's become very frustrating.

The process of converting the ASH was a little stressful to start, cutting a perfectly good fuz like that is always going to make you a bit nervous. BUt now I've done it, I intend to do it again several times. Prolly use the Torcman setup next time so that I can remove the prop and yoke and leave the nose pretty much untouched, although it's £200 a pop, so not a cheap alternative.

The Hacker motor is superb, I've just changed the prop blades to 13x10 so the ROG will benefit from a little more clearance, as you can see, our field 'helped' launch the model. As per Carolynne's advice, I kept a little up elevator in to stop the nose dropping and the prop striking and as you can see, the model leapt into the air in a very confidence inspiring way. I now have swapped out my Jeti Mezon ESC as it started playing up, so hopefully I will be able to do a lot more testing as soon as the weather clears up.

We do a lot of aerotowing at our club and Jared has an FES 1/3 Ka6 he regularly flies, so my model was within normal activity really, certainly quieter and less stressful than aerotowing.

My advice to any glider flier would be to do it, you won't look back, I can't wait to get the next big glider on the bench, just have to save for another setup...

Cheers, Ell.

PS. I know the landing was awful, must have been the pressure

Hi Elliot

How much ground clearance did you have with each of the props?

Phill

We do a lot of aerotowing at our club and Jared has an FES 1/3 Ka6 he regularly flies, so my model was within normal activity really, certainly quieter and less stressful than aerotowing.

Did you mean:- We do not do lot of.??

P.S. I know the landing was awful, must have been the pressure

Or it could just have been the iffy pilot...

BC

Barry, nope, I meant we do

Phil, there's plenty of ground clearance if you have a smooth runway, I've now made a dolly for this model as you can hear the prop strike just before take off... I tried going down to a 13x10 but there's nowhere near enough grunt, 14x10 is perfect.

Elliot,
If you go from a 14 x 10 down to a 13 x 10, you will get about 2/3 of the power. You need a 13 x 13 to get about the same power.



BC

Thanks Barry,

I had realised that I'd get less power, but the difference at our slightly lumpy field is dramatic, the 14x10 absolutely leaps off the ground.

I can't find anything close to 13x13, it would seem to be an exotic size.

Ell.

Hi Elliot

I’ve got the same motor on order and have been wondering about cooling.

Does your motor get very hot and did you add any cooling vents?

Thanks

Phill

I’m sure you’ve thought of it already but the best way to compensate for the reduced torque of the smaller prop is to boost the rpm by increasing the cell count of the battery. Even if you could find that elusive 13 x 13, I’m not sure it would produce much more low speed thrust, which I guess is what you’re after.

just thinking out of the box, why not put bigger wheels on your trolley or make it slightly higher ? that way you can keep the good prop

Phil, I use the schambeck spinner which has a cooling hole in the nose, not sure what temps I was seeing at the motor, I know the telemetry from the ESC was reporting a cool run there.

Trevor, I'll have to look into higher cell counts, although at 8s I'm pretty snug in the battery compartment already...

Mick, I have actually made a dolly, I was hoping to run from the retract only, on a smooth runway, it would be fine, there are a few smalls bumps in ours.

UPDATE

so, the motor shaft needed a flat filing on it, now my spinner doesn't want to disappear every time I whack 2.5kW through it...

the retract is not quite long enough to enable a safe launch every time, a FES suitable retract will be sourced and fitted ASAP.

The motor/ prop combination is perfect, I don't have figures yet but hope to when I get the retract sorted, I would imagine I'm looking at 4-5 launches to thermalling height per charge (5amp hour 8S).

All in all, a great success.

Well done Elliot, Once you've got used to it,you'll never go back. So independent of tows, so much safer on the slope.

Terry, I love it too much! I've ordered a tow release for FES models from Let, so will be able to do that too soon, although the freedom of self launch is quite liberating. And no one in my club has a 100cc tug