Jonathan M

I'm not the most expert thermal flier but, once the turn has started, one maintains (or alters) it's radius with rudder, using ailerons to hold the appropriate bank angle - sometimes opposite, sometimes the same. A totally flat turn would be draggy and inefficient, but too high a bank angle would reduce the vertical component of lift, so the sweet-spot will always be somewhere in-between. Watching the transmitter of a very experienced friend flying F5J comps, it is astonishing how his yaw, roll and pitch sticks are in almost constant movement (both gross and fine) to keep balancing things for maximum efficiency. It is too much to go into here, but how a high-aspect wing thermal soarer visibly responds to the air it is in, as much as to your controls, depends on where it is relative to a thermal core - very different to neutral air or to sink. Clearly a narrow core low down will require a tighter bank to stay in it, but higher up once it's more fully developed the turn can be flattened for greater efficiency etc. Also thermals aren't necessarily circular or regular and they can elongate as they move downwind, so different parts of the flying 'circle' (or 'oval') will need different control responses... especially if you find yourself spat out of one! So - returning to the question of coupled rudder or not - I've gradually learnt to leave everything independent so that roll control doesn't confuse my desired rudder output at any given point.

Thanks. I used to have a drawer of old A4 report covers and the suchlike, but can't find it after my two moves! I'll order some 0.5mm.

Thanks Nigel, good point about vibration. I have a spare HS81 ready to go, so will use that. And thanks also for the heads up on 0.5mm acetate. I'm sure a small lipo would work fine, but my 'mindset' for IC power (and slope soarers) always thinks in terms of 'NiMh', along with the flight times and charging routines that go with that. I'll probably use a 4.8v Eneloop 800mAh AAA pack. Wondered about a 6.0v (i.e. five AAA cells) pack, but can't think this 2.75lb model is going to need the extra volts really.

I like that logical switch setup - even if I don't think I'd personally be able to handle the pilot-workload for GPS Triangle racing! It easily takes dozens of flights to optimise a particular thermal soarer. And, as far as differential is concerned, I typically use none at all in speed mode, a modest amount in cruise, and most in thermal - where where it is most critical for efficient but also slow flying nearest the stall.

Need to make a simple wrap-around (i.e. non-moulded) canopy for a 47" span model, see build blog here What thickness acetate would I need... and where to get?

I agree in principle, but if one gets used to manual rudder input all the time at normal lower altitudes, then the correct amount of rudder to aileron input should become more or less automatic and accurate enough whatever the height of the model. Also, in thermal mode especially, one is constantly playing some degree of opposite aileron to rudder in order to maintain a fairly flat turn to maximise lift, especially when scratching in weak conditions. Coupled rudder would completely mess this up, so it's actually better to leave the switch off as much as possible.

Absolutely, and just to add briefly to what I posted previously: I tried to be as non-partisan and diplomatic as possible in what I said, not an easy task. If those in either trench read it that I was supportive of their cause and took encouragement from that, then that certainly wasn't my intention. I'm suddenly reminded of what my late dad would say from behind the wheel of the family car in the mid-1970s (a blue Ford Grenada that kept having the wheels nicked off it and replaced with ones with totally bald tyres): "I don't care who started it, or who gave who The Look first, if you three don't pipe down immediately you'll all get a hiding!!" 🤣

Thanks Geoff. Yes Dereck suggests differential, which will be very easy to tweak from the radio with separate aileron servos. Talking of servos I intend to use 20g Hitec HS85 metal geared servos all round, except for throttle which doesn't need more than a simple low-weight micro, e.g. a spare Emax 8g. Battery-wise, I can see no reason to fit anything with more grunt or capacity than a small 4.8v NiMh pack to avoid extra weight. Choice is between an Eneloop AAA pack at 800mAh, or a 2/3AA 700mAh pack (as used in my DreamFlight Ahi), both around the 50g mark, half the weight of an AA pack. All this modern 'lightness' should make up for my adding a slight amount of extra weight by beefing up the wing to full D-box (rather than just top sheeting as per plan) and adding 1/16th sheer webbing (which again the plan lacks). Also arrived in the post two rolls of Oracover for a vintage-like scheme: mid blue fuse and fin/rudder, cream wings and tailplane etc. Maiden coming up shortly...! 🤣

Glad to hear this James. Hope my build-blog will be of use as well as interest! I had worried slightly that the 30 FS might be a tad too powerful, but I expect it'll be alright. BTW the Outerzone site is working again, so go here for Amelia plan and article

Finally the fuselage formers to fashion. I have quite a lot of 1/16" birch ply (and only a single sheet of badly warped 1/8"), so F1 was first laminated up from four pieces of 1/16" and F2 from two, in both cases 'mirroring' the cutout parts cancelled any twist or cupping in the sheet, resulting in totally flat formers. F1 took a bit of thought as to where everything will all fit or protrude through (I'll probably move the engine mount over a bit to allow for a tad of side-thrust), and F2 has a hoofing great square hole cut out for the 4oz SLEC tank. F5 is supposed to be 1/8" ply but I went for Lite-ply of the same thickness. Should easily be rigid enough, but can always glue on a couple of cross-pieces of 3/16" square later to keep it all honest. F4, which forms the cockpit framing, looked a little delicate and also fiddly to rough out and shape! So I decided on 4mm thick Lite-ply which is easy to cut with a hand-held coping-saw. The outside curve will be accurately smoothed using a setup similar to the Permagrit one (on the birch ply formers) below, while a sanding drum on the stand-mounted Dremel should cope with the inside curve. I no longer have access to any full-size woodworking machinery. I thought about investing in a Proxxon fret-saw or even their weeny bandsaw for this sort of thing, but it isn't really necessary at this stage of things... I actually enjoy using hand-tools, jigging things up manually to achieve a suitable result, and it's not as if I'm under any time-pressure... ! 🤣

Still in the pre-build world of kitting my own parts! Now for the fuselage sides and formers. My method is to simply scan parts from the plan and print onto A4, taping sheets together if necessary, then Pritt-stick or spray-mount these onto the sheet wood. I found that shop-printed plans will transfer perfectly (in reverse) with a hot iron onto sheet balsa or ply, but inkjet printed ones won't. The outlines for the 3/16" sides and 1/32" doublers are each indicated with little triangles, white ones for the balsa, black for the ply. There is a minor error on the ply plan outline aft of the wing TE, corrected on the paper template before cutting out the ply itself! Finally marked up the positions of formers 1, 2 and 3 - took positions direct from the original plan for accuracy. Note also that I pre-sanded the ply to clear the surface of release-agent, else the glue won't stick later on!

First job, having simplified and standardised the rib profile for all ribs, was to transfer to two 1/32" ply templates, trace onto sheet balsa and rough out, sandwich up in sets, razor plane and sand, and then form notches for the spars. Once the full set was complete (1/8" for the centre-section etc, 3/32" for the others), bored and sanded 10mm diameter holes for the aileron servo wires (will have paper tubes).

I'd been looking for a while for a suitable kit or plan-build for my OS30FS, which I'd bought new a decade ago. I thought about Peter Miller's original smaller Peggy Sue (even bought the plan) or his Ohmen (short kit converted to IC), but finally decided on the Amelia (see this thread from 2023). I ordered the wood from SLEC a year ago and ran in the engine on the test-stand, but work, life stuff and a second house-move in two years delayed things more! Now settled, with my first proper making space in nearly three years, and have made an actual start. There are a few confusing errors on the plan (I assume from whoever inked the drawings), notably how the wing centre-section works (I'll go through this later), plus my own minor mods: wing will be bolt-on rather than rubber-banded separate aileron servos in each wing rather than single centre one will do a full D-box construction with cap-strips rather than the top sheeting only etc (also simplifies rib-making!) and add sheer-webs won't have removable tank hatch under fuselage (to prevent fuel soaking in), tank will be removable by withdrawing aft through F2 The Outerzone site is down at the moment, but the plan and article can be found there when it is working again.

"Daly for the line!!... Daly for the win!! England's Black & Decker Workmate!... the jack-of-all trades!" - English match commentary at its finest! 🤣

Just to say that as the person who started a recent thread that was in the end locked (and I think a previous one from the past which also suffered the same eventual outcome) I come on here to learn, share what I've done or what I know based on my own modest experience, and generally enjoy myself. The overwhelming character of this forum is friendly, well-mannered, and helpful. The mods do a fantastic job keeping it all clean, good-humoured and functioning, but it is fundamentally actually the responsibility of us all to keep it that way. I'd suggest that if one or two people have a forever bone to pick with someone else in particular then, instead of jumping on every third-party thread where that person offers the benefit of their knowledge or expertise, they think twice before doing so, or at least enter the discussion with an open mind and/or present a careful and respectful case of their own ... or better still start their own thread! It isn't pleasant to watch differences of experience become inflamed arguments, let alone have useful or interesting threads locked. It will be for individual readers to form their own conclusions as to the merits of different views - not for detractors to relentlessly prove themselves against someone else. Happy landings!

I've thought about a servo mounted on the test stand (via either a RX or a servo-tester plus battery) but the time taken to set it up for each different engine would be an unnecessary bother, plus it'd all get covered in exhaust residue. My wire is held with a thick rubber band to the side of the fuel tank, which provides just enough friction to hold it at setting... KISS My kill switch is always the one directly above the throttle stick, down is dead, up is live... makes sense to me and I've got used to it. When carrying a running IC model from the pits to the runway, I move the stick to one click above idle to prevent an inopportune cutout, then hold the TX by the carry-handle in my mouth, controls facing forward so unknockable. I know some people have a fast idle on a switch (e.g. for spins or safer landing approaches) but my brain can't handle more than one thought process every two minutes, so again I keep it all simple via the throttle stick. Same with using trims as a control... I get confused! 🤣

On the test-stand I have a simple hand-operated piece of wire, so the carb goes from wide open to fully closed. Fully closed will starve the engine of fuel and air, tickover will be with the barrel mouth open slightly, typically say 1/16th in (1.5mm). In the model I personally don't touch throttle-trim, just leave it at neutral. Instead the throttle is set up on a simple straight-line 2-point curve on the radio. One point is stick fully forward and carb wide open (but no more else the servo starts buzzing and gets stressed). The other point is stick fully back and carb slightly open to give a reliable tickover, and it is this point's value that I can easily tweak in the radio menu. A separate throttle kill switch closes the carb completely. This system has the advantage of not messing up the reliable idle setting between flights, etc. An example of this setup on one of my models is (max available servo travel = +/-100): Stick forward: curve point at +60 (found by trial and error, i.e. when barrel is fully open, but no more pull from servo) Stick back: curve point currently at -64 (last time I flew, -62 was too fast, -66 too slow) Throttle kill switch (which overrides the curve): -85 (carb fully closed to stop engine, any more would result in servo buzzing under load) I hope this makes sense. Your transmitter might have this facility (to put throttle on a curve and change its end-point values, also to set up a kill switch), but if not then just get used to using throttle down-trim to kill the motor.

Just had a look at the manual online, which repeats 115mm three times, putting CG at nearly 39% of root chord which is mad, especially for such a heavy, tapered wing model. I imagine most of the problem will be avoided by moving it to circa 30% to start with, then turbulator tape if needed, then mix if still really needed.

From the Outerzone blurb: "With a wing span and area of 69in and 850 sq in respectively, the Duellist II is intended for .19 up to .40 engines". A 50% increase in capacity equals between 30 and 60, so Dale's preference for two 46s looks adequate enough.

First class ramblings... fascinating project! Working link to plan here

On a related note... helped a guy today joining our club who is a skilled electric flyer but a complete IC newbie. His interest in learning IC is because he was recently gifted (from someone now deceased I think) a very tidy (maybe hardly or never flown?) Arising Star with an equally almost pristine SC40. I'd assumed that this engine had at least been run in the distant past (the model came with an old 35Mhz rx), but it was quite tight before fuelling and remained so after a ground run to tweak the needle etc and then a ten minute flight, plus there remains a double click around TDC. What to do? Should I assume this engine was never actually run at all or maybe never fully run in, and/or never allowed to get hot enough etc? It runs fine when it is going, but takes a while to start with the electric starter, and hand-flicking got me nowhere. It seems otherwise completely reliable and pulls the model around quite adequately. How should we treat it going forward? Give it an Italian tune-up right away, i.e. thrash the beans out of it, or just fly normally and hope it gradually eases in...?

Yes I did wonder about that. Not that I know anything at all about the chrome (the C in ABC I assume?), what causes its loss, or how that can be remedied, if at all...?

Yes, I've got one of each of those props, but didn't want to overload the engine too early on. I'll try the 12" props tomorrow, see how they compare - then I've got a potential new member to have a go on the buddy-box.

And today I did do exactly that! 1st ever tank was 15mins on the ground with a 10x5 prop, saw 13600rpm max (briefly) and got idle down from factory 3000/3500 to about 2500. Two 12min flights later (cooled between runs) with an 11x6 prop peaked at 11300, with idle tweaked down to a consistent 2300, and the desired very slight hesitation only on pickup. Hand-flicking from cold with just a charged up glow-stick (as I'd normally do on well run engines) wasn't happening at first: in addition to the total newness of the engine it was also cold and damp, breaking into mizzle at times. So I used the 12v panel wired glow-stick dialled up to a generous 1.5v to get it going, but later on with the engine loosened up the portable glow-stick worked fine. I can't remember the last time I used the 12v electric starter... but I always lug it along just in case! Great engine! Clearly more power for the Irvine Trainer than the Irvine 46 it came with, which was reliable at first but then kept hunting and dying on me last summer. I haven't a clue what might have been causing that... but the OS proves that it wasn't the plumbing!

Mike the very first rule of data security is to NOT publish your email address openly!! There are bots that constantly scrape the internet for private data! PM (private message) it instead to Richard - and ask one of the mods (moderators) to edit your post as it is probably by now too late for you to do it yourself.