Jonathan M

I haven't flown since the Spring (don't ask!) but a week ago I took the Ahi to a local micro-slope in windy westerly conditions and had good fun. Obviously if the wind was a little more in the NW I'd have flown the Middle Phase in much bigger skies off the main slope... but arranging these things is beyond me. Late afternoon today I took the IC Boomerang up the patch. As it was blowing 15-22mph, therefore significantly increasing the usual slope-lift/sink and turbulence, I was happily the only person there. I'd have quickly become frazzled flying, say, the IC Wot 4 balsa ARTF, but the heavy Boomerang is my go-to model for such windy weather. (As it happens, I'd just fitted a finer-pitched prop to slow the beast for landings - it bullets on endlessly in lighter winds - but for some reason landing-runs were pretty short as it was...!)

Proper woodwork! ? Watching with interest Gary...

Might not yet be finished but certainly already has its cheeky, plucky appearance! Re the cowling, I was thinking of just beefing my one up with GF and epoxy...?

New 3s 450mAh Lipos arrived, as did a third prop for the static tests, and this was the outcome: 8x4 peaks at 67W/lb on the first 15sec run, dropping to 63W/lb on the fourth 15sec run; and after resting Lipo for ten mins it's down to 79% capacity. 9x5 peaks at 96W/lb down to 90W/lb on the fourth run; after resting down to 70% capacity. 10x5 peaks at 115W/lb down to 100W/lb on the fourth run, 67% capacity. Obviously the weaker prop combo will take longer in a shallower climb to reach the same 60m altitude as the medium/powerful prop combos and use up more capacity in doing so, but until I get it airborne and practicing F5-RES stuff, I won't know exactly which prop will give the right balance between climb performance, max number of launches per Lipo, and remaining capacity for soaring etc. Also of interest is that the 8x4 prop only peaked at 6.4A (the 9x5 at 9.4A and the 10x5 at 10.8A) which means that the punier prop would allow a much lighter 10/12A ESC to be fitted. Today's work-in-progress on the Six Million Dollar Glider (the now shortened nose needed widening from an internal 22mm to 25mm just in the area of the 23mm motor diameter for clearance, which was ever so fiddly):

Thanks for the commiserations Peter. It hurt a bit at the time, but also taught me a big lesson about what's an acceptable horizontal range for these light fixed-camber gliders! And more importantly its now given me a fun repair/conversion project... ?

Cheers Pat - lovely to see, and a respectable enough climb on just 80W/lb. So if, my calcs for the model of about 100W/lb on the 9x5 are right, then it should easily get to 60m in 12-15 secs (the current generation of 2m RES models have much more slender fuselages and thinner wings so less draggy all round). Else have a 10x6 on order and will run the static tests again when the new batts arrive - and repeat in the air. Its an X-RES which I bought second-hand a year or so ago and flew as a bungee-launched glider until I got caught out in a boomer much too far downwind. I deployed spoilers but then had difficulty in regaining orientation at that great distance (a 2m span looks very small indeed at 300m high and 1km away!) and lost signal when it came down the other side of a hill. After an hour's search with the dog and a pair of binos I found it - nose smashed in the earth with a broken back and some wing damage - so set it aside. (I resumed flying off the bungee with a used PuRES I bought shortly afterwards, with which I've had great enjoyment and some good duration success, most recently about 33mins off a modest 45m launch). Now I've decided the X-RES will make an excellent candidate for conversion to electric-launch... after all the nose is already 40% shorter!! I love the simplicity of the bungee, but electric will open up a wider choice of thermal flying sites. But the challenge is to keep the extra weight right down, as these F3-RES and F5-RES models are only good for relatively light wind days (say 5-8mph, 10 max) and there's no point in carrying unnecessary ballast if it can be avoided. Pics below are of the model as originally re-covered, and then the fateful day...

Thank you - very clear and illuminating!

That's very revealing and useful - gives a rough rule of thumb of between a fifth and a quarter less. It would also suggest that a smaller ESC could in fact be safely used with my own comparatively tiny power-train, but (i) there'll still be a large peak draw at hand-launch with the motor at full tilt but before the airframe has picked up speed, and (ii) although the motor run is short there isn't the same ESC cooling as on power models.

Thanks for the replies - all very helpful. Ran another static test with the 9x6 but with a larger slightly less ancient 3s on 50% charge, which gave me another volt on top and therefore a 100W peak. On a full charge (or better still fully-charged brand new 3s 450mAh batts for the model) this should be even smarter, say 12v, so power of about 110W peak, which equates to 100W/lb which sounds just right for the sort of 45°-60° launch needed. Clearly a bigger prop will eat more Amps and therefore Ah, but the rules of the game (F5-RES) are for a max 20sec motor run and an altitude limit of 60m for the launch, so more than happy now with this as a starting point. Also now found a good quality 20A ESC that's much lighter than my existing one - more sensible to have a much safer margin than risk a 10/12A unit.

I'm trying to determine a power-train for a lightweight 500g electric-launch 2m RES glider, so keeping weight down is important. My static tests with a watt-meter and a spare but heavy 20A (max 30A) ESC produce a peak draw of about 9A (at roughly 10v so 90W power) from a fully-charged 3s 450mAh. Ideally I'd like to fit a much lighter 10A (max 12A) ESC to save weight. (This is with a 9x5 folding prop; waiting for the 10x6 to arrive to see what the figures are for that; and don't yet know what I'll use in practice as I need to find a balance between enough power for an efficient climb to 60m within 10-20 secs max and conserving capacity for several launches plus actual thermal flying etc. Also my test battery is quite old and tired with a much poorer C (and burst) rating compared to modern ones, so not convinced its full charge is as 'fit' as a new one's would be. Needless to say, after three 20s runs at full tilt the peak figures drop somewhat!) So my basic question is this: what can I expect the maximum current draw to be in actual flight? A bit more than the 9A static figure... or a lot more?! If a lot more, can anyone recommend a good but light 15A ESC? Finally, although I expect only experiments in the air will give me the answer, is 80 or 90 W/lb going to be enough power for this sort of model?

I'm facing the same issue - a 2019 X9D Plus still on the original OpenTX 2.2.4 and firmware and a dozen RXs still on ACCST 1 etc - which all works perfectly, and I'm loathe to have to do anything more than just use it to fly models! So, what is the merit of NOT changing anything? The only downside I can see is that, if all new RXs are only now available with ACCST 2, this'll mean flashing them back to ACCST 1...?

I agree: it isn't the parts-count that is important to me, it's the fact that it'll build to be a proper robust model, whether electric or IC. Case in point 1: my balsa ARTF Wot4 tipped onto its nose just after landing the other day (it was gusty), the SC40 was already at or close to idle yet the tip-strike still managed to remove the entire motor-mount from the firewall. Case in point 2: my ARTF Boomerang came down a bit awkwardly in a sudden crosswind and rotated (yawed) heavily in the rough grass beyond the runway, the nylon wing bolts didn't sheer, instead the lite-ply plate ripped out and half the mid/rear fuselage was shattered. Mending it all took two days and untold frustration at the near impossibility at piecing the components together, cleaning up the sharp residues of roughly-applied manufacturing glue, and finding a glueing system that would stick to the lite-ply. I don't imagine the Musketeer would suffer from the same flimsiness or torture of repairing.

Re stakes, whilst a screwdriver isn't a wise idea, I have complete faith in a corkscrew dog-stake. Mine is even a miniature version (for lapdogs if you like), but the bungee is only 10m of 6mm diameter tubing (plus 50m of 30 lb strain fishing-line), and I'm only ever securing it into solid earth, not estuary mud or beach sand. The static pull at full extension (I do 3x for a 320g 2m wingspan RES model) is very modest, under 4kg according to the rules (less than holding a very small child in a tug-of-war), the angle of pull before release is effectively wholly perpendicular to the stake thus the maximum force is entirely sheer, and there are no shock-loadings at all. After release the angle of pull does increase progressively up to about 60 degrees or so, but as it does so the tension progressively decreases. Under these conditions, I've never felt there was anything worry about with my mini-stake: after several days recently of using this setup for scores of launches each day, removal of the mini-stake at the end was as laborious as it was securing it into the ground in the first place. For an 8 or 10mm diameter bungee the forces will obviously be increased, but the mechanics remain the same and a single regular-sized dog-stake should be more than safe.... unless carelessly secured in loose earth etc!

? Well done!

If you find you need a bit more help with visibility, while avoiding paint reaction issues, there's always the option of some brightly-coloured self-adhesive Oratrim (or similar film product) for added vitamins...!

Neat and very efficient refurb jobs on both Phases, and the home-brew graphics finish them off perfectly!

You could do the crow, but frankly if you're going to go down the route of adapting the wing etc I reckon it would be better to just fit two servos, one for each of the full-length ailerons (I fitted HS85MGs in hollowed-out pockets, which are small but more than strong enough for the job). I've never had a model with flaps so have never used crow, but the spoilerons do a very good job of dumping lift, slowing the model a bit and getting it onto the deck when needed. The other thing about having separate aileron servos is that you can then mix in a bit of snap-flap - I did this mainly because I wanted my MP to be able to fly inverted slightly more easily, which works a treat. Re the tailplane, I don't think I'd be happy with a glued-on one- its too vulnerable in my view, so either bolts (carry lots of spares!) or rubber bands.

Basically the rubber band goes from under the fuselage at the LE of the tailplane, up and over the fin etc, then down through the 1/4" deep x 1-1/4" wide rectangular hole cut at the rear of the fixed part of tailplane, then down and into the angled slots just under the very end of the fuselage. Hope this helps.

Mike, I'll see if I can dig out my own instructions. The fuselage-mounted aileron servo is the original design, nothing at all wrong with it at all, except that with my two wing servos I've been able to programme in spoilerons on the throttle-stick (full up is normal, full down is max up travel on both) to help fasten the model down on landings in tight areas. My tailplane is bolted on with M3 nylon bolts... I wish I'd banded it on instead!! Jon

The Boomerang as it has a semi-symmetrical wing section (it won't 'balloon' in turns). But if you've got the time and skills/inclination, then you'll be much better off building a proper IC or electric trainer from a kit than flying a balsa 'shattering-ply' ARTF. The ARTF Boomerang is a very good model, but as an ARTF it does suffer from this cynical method of manufacture - I know as I've had to (i) order a new fuselage to replace the first one which shattered on a pancake, and (ii) manage to work through my frustrations in mending the replacement fuselage which also shattered albeit not as terminally in the most awkward of places after coming down in the rough. If you've built a proper balsa model, you'll be able to mend it yourself. Really good kits for someone in your position are: Chris Foss Uno Wot trainer SLEC Sky 40 trainer While you are building your proper trainer, you could still get flying with a lightweight RTF foamie, either something with undercarriage like a ST Models Discovery, or a powered glider (there are lots to choose from) which will be flyable from hand-launch and will be docile enough to give you experience of controlling, the effect of wind, orientation, learning to anticipate actions, etc. But first join the BMFA, and join a good local club which has instructors. It'll take you at least a season to learn to fly properly and safely. Allow several years to really build up experience etc. A simulator can be a real help, but there are no short-cuts to gaining experience with a real model at the field - its practice, practice and stick-time that counts.

In the meantime, I had my first thermal session yesterday, which was off-patch as our hill-top site isn't ideal and to avoid bungee-conflict with the power flyers! My PuRES 2mRES was bought second-hand last year and re-covered with Oralight; for added lightness the carbon snakes were replaced with pull-strings and springs in the tail. Took a couple of hours to re-trim, and get used again to its ultra-light gracefulness and re-acquire the necessary 'mindfulness' of working the air... and not stalling which costs 5-10m each time! Still something of a beginner with this flat-field malarkey! Finally, although there wasn't much thermal activity in the afternoon, I got a lovely ten-minute flight off an 80m launch (10m of bungee plus 50m line) around tea-time.

No-one in our club didn't re-join out of nervousness, only losses at renewal were one or two who were moving away from the area. That said only a third of the total membership ever seem to turn up to fly, and only about a quarter are regular at the patch.

Durr! [slaps own forehead!]

Nigel, you're absolutely right about more up than down with the horn set slightly aft - exactly what I'd normally want as a starting point - clearly got my own mental wires crossed in my earlier post and thought it was the other way round!