Rough Field Flying

To get back into model aircraft after many years away I've been flying a couple of electric foamies up in the moors around where I live, hand launching and landing back on the heather. Managed to get a fair bit of stick time without the hassle of having to have someone buddy me as I would at a club field.

For something to do during the grim winter months I built Seagull Boomerang kit (traditional balsa and ply build) and again went electric.

I went up the moors for a maiden flight at the weekend and thought I'd have a quick test glide. Bit of a heavy landing in the heather (but no worse than would happen at the end of a powered flight). Result one broken prop and a bent motor shaft.

I'd not fitted any undercarriage as I was hand launching and landing on heather. I hadn't figured on props and electric motors being so fragile , though of course at 2.5kg the Boomerang is a lot heavier than the foamies I've been flying.

Any suggestions as how I can prevent a repeat (besides fitting the undercarriage and joining a club with a grass strip).

Incidentally anyone know the size of Allen key I need to remove the bent shaft on a Turnigy SK3 3548 ? It seems to be between 1.5 and 2mm

According to the Hobby King web site the Turnigy SK3 3548 uses M3 bolts.
According to this web site an M3 hex key is 2.5 mm across flats.
The fact that you bent the shaft doing a belly land perhaps suggests you need a weaker prop rather than a stronger one!
In very rough ground adding undercarriage is a mixed blessing. It comes down to which is better, breaking a prop or ripping out the U/C?
The only other solution is to put the ESC brake on which might stop the prop rotating if the gliding speed is slow enough. Unless the prop stops exactly vertical it stand a good chance of being knocked out of the way.
It is a technique I use on my rough field belly landers but ultimately its touch down speed that is the prop killer.

Folding prop?
Mike

Undercarriage and Heather do not mix well and is more likely to make matters worse. I know this well as quite a few in my area learned to fly years ago using such landing stuff. It also looks like you are getting close to benefiting from a club environment,, Buddy companion depends on the club of course, but need not be too onerous, especially as you are already getting "stick" time in to regain control ability. Imagine a typical Club flying area, and practice within the area/ landing zone, and you will have cracked the basics for quick club pilot pass. Hopefully

Have fun.
Ps, Slope Soarers seldom have undercarraige.

Thanks for your thoughts guys. I had wondered if a folding prop might be an option but a bit of googling suggests that these are designed for power assisted gliders. Too small and flimsy for the Boomerang.
Maybe I should take up the other suggestion - remove the motor and battery and use it as a slope soarer ????

More seriously I guess I'll just hang onto it and fly my foamies until I feel ready to join a club and take the A certificate

Incidentally I think the M3 mentioned on the hobbyking website is the engine mounting bolts. The grub screws are much smaller than that

Cheers

Al

I think you will find folding props can be far from "small and flimsy".
Competition gliders are expected to be able to climb vertically from a hand launch. Aluminium hubs and carbon fibre blades but not cheap though.
This 18x10 is claimed to generate 6.5 kg of thrust using a Turnigy SK3 5055-320 on a 6s LiPo.

That's the sort of thing that made me suggest a folder
Mike

I stand corrected gents - some pretty serious kit there

I'd still be a bit concerned about those carbon fibre blades though, presumably very rigid so great for performance on a competition model but for my needs (relatively heavy model, rough landings on heather and performance relatively unimportant) I'd be happier with something more flexible like good old fashioned nylon. I can only find carbon ones in the sizes I need (12x7 - 13x7 or thereabouts)

I stand corrected gents - some pretty serious kit there

I'd still be a bit concerned about those carbon fibre blades though, presumably very rigid so great for performance on a competition model but for my needs (relatively heavy model, rough landings on heather and performance relatively unimportant) I'd be happier with something more flexible like good old fashioned nylon. I can only find carbon ones in the sizes I need (12x7 - 13x7 or thereabouts).
One additional consideration. From the pictures I've been able to find on the internet the props on powered gliders fold flush with the nose of the model. With the Boomerang this may or may not be the case depending on the position at which the prop stops

Eric wrote: p.s. DON'T try using a folding prop on an i/c engine!

Certainly not normal commercial folders - although custom made folders are de riguer for may top line F1C models, with powerful 15s turning around 30,000 rpm.
Mike (another nylon boiler from the good old days!)