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  2. The way to think of using Depron i.e. thin sheet XPS foam, is to consider it as a stressed skin with an internal supporting structure. This internal structure could include carbon rod(s) for extra stiffness. It is likely the resulting structure will be thicker that a simple balsa 'frame' but it can be a streamlined aerofoil to compensate. It is quite possible that a good streamline shape can be twice as thick as a balsa frame structure and still create less drag. It is also likely to be aerodynamically more effective. Fully covering a Depron structure in some way will increase the stiffness but it can add significant weight. How much weight you can save will very much depend on how stiff you want the Depron structure to be. If you use Depron as a single slab structure it is likely to be too flexible even with leading and trailing edge reinforcement. Depron substitution in a load bearing structure is likely to require some experimentation to achieve a weight saving with sufficient strength. As an example the tail plane on my Bombardier Q400. It sits on top of the fin. All 3mm Depron except for the tapered balsa spar flanges are set flush with the Depron skin to give the maximum possible spar stiffness for minimum weight. Not exactly a 'simple' structure but strong enough for its purpose as a twin prop airliner and that includes doing a loop!😮
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  4. Hi I have just purchased a glider out of an estate without an any specifications. I have managed to track down a post by PatMc on a John Hall Diamond and this appears to be the glider I have purchased. Not sure that PatMc had the original specifications since it dates back to 1980, but any help would be appreciated, particularly with the COG. Ian
  5. FYI: Combined fin and rudder covered in brown paper and sealed ready to paint: weight = 14.5g, area = 220cm2 ==> 660gM2 ballpark That's for 6mm XPS foam with 1/4" med balsa hinge posts (10mm and 20mm wide) and 3/32" sq hard balsa edges with foam sanded to slight profile. I think I've done that correctly. I believe Depron is slightly lighter than XPS foam sheet, though not as nice to sand.
  6. I stuck 6g servos with hot melt glue and covered my Coyote with Solarfilm. If they ever need replacing then I just cut the film and cover with a patch. Your 9.8g servos will be perfect.
  7. For such a powered model I'm not entirely sure if strong enough Depron tail feathers would save much weight compared to an open balsa structure. I'd be inclined to try a 'solid' Depron (or similar foam) outline, edged with thin balsa for ding resistance. Add more substantial balsa 'posts' at the hinge lines and to give strength and bending stiffness. Don't over do the balsa otherwise you are effectively in-filling the structure with Depron where there was previously thin air, if you follow my meaning. Then cover with brown paper (and PVA) to really ramp up the the torsional and bending stiffness. Cutting lightening holes in the foam would rule out brown paper covering for a more conventional covering material, though I doubt would save much weight. And it may not be as stiff. Brown paper can form a surprisingly stiff edge on a curved leading edge, so thin balsa edging could be omitted if you were striving to save fractions of grammes and you were careful to avoid hangar rash. Here is a picture of the twin fins and rudders for my current EDF model using the foam and brown paper approach. The thicker balsa post on the rudder is because I shall be using a long double sided horn (similar to on a closed loop rudder) to transmit rudder movement on to a vectored thrust unit. Personally, I would happily use this construction for a 52 IC powered model without fear of flutter ruining my day. I'd be happy enough to weigh and measure the areas of my fins to give you an idea.
  8. Every year I compete in a daft competition for a three-channel French trainer. It is known as La Coupe Des Barons or the Barons' Cup in English. You are allowed to make alterations to the structure and dimensions of the original model providing that they remain within 10% of the original design. I have two Barons, Boris in Ukrainian markings and Bertie with the British roundels. If I were to crash one shortly before the event then I'd have a reserve aircraft. This actually happened last year! This year I built a new wing for Bertie, using depron for the wing ribs. The completed model is fully 4 ozs (113 grammes) lighter than my Ukrainian Baron which is stock and built from a kit. For the 2025 competition I am thinking of building a new lighter fuselage and tailplane for Bertie using depron for the tailsurfaces in order to save yet more weight. The stock tailplane is made up of 1/4" (6mm) balsa. The model will be powered by a 52 fourstroke because I always compete in the fourstroke class and have given a prize to the leading pilot flying a four-stroke Baron for the last few years. I guess that I am quite famous being the only British entrant and a fourstroke devoté to boot! My question is, "How do you make a tailplane, fin and rudder out of depron sufficiently robust to withstand the flight stresses ofr a Baron in competition when powered by a 52 four-stroke?" Pictures below of the construction of a stock tailplane and the depron wing, and of Bertie and Boris ready for La Coupe. My dog is such a diva that she just had to get into the act!
  9. I'm in France but please don't hold that against me!. I am not adverse to selling some on once I have built and tested one 🙂, especially if the panelising works because with 6 boards to each panel and the minimum order of 5 boards I will have a few spare. It cost me ~$10 per batch but it kept me busy the whole day so I see that as a good price for a whole days entertainment - any price will be pretty much just postage.... if it happens! I have also done a design using a Seeed Studio Xiao ESP32C3 instead of the super mini. I have a few of them and as the design doesn't employ wifi it doesn't need the external antenna those boards come with. I don't suppose anybody will really be interested though because the Xiao costs quite a bit more than the super mini . Incidentally, there are two ESP32C3 'super minis', this is the one you want - This is a ESP32C3 Zero, sometimes conflated with a esp32c3 supermini, it has a RGB Led on board and has a different pinout - Easy to confuse the two! Here is the Xiao - It is very slightly smaller than the supermini if you ignore the external wifi antenna Quite a few of my previous boards ended up in the bin too, it is amazing how little time you need with the PCB in your hand to spot the fubar you spent a whole day looking for before pressing the 'buy' button.
  10. Have you reported the issue to RCG?
  11. Thanks for the suggestions so far. Economics do play a part in repairing an old engine. The engine in running order is probably worth £20-£30, so it will end up on the spares pile of too expensive to fix.
  12. I subscribe to RCG and lately when logged into RCG site (Via Firefox) I have noticed the occasional uninvited download request of a PDF or an HTML document in the background that was not requested. Sounds dodgy to me. Beware! * Chris *
  13. Sticking a couple of servos in the wings on a SLEC Coyote, first proper model so I didn't think to change the build slightly to incorporate screwed in servo mounts and instead did as the instructions said and glued them in. This means once the servos are in the only way to remove them is to cut the covering. I need a recommendation on mini servos that aren't overly expensive but are reliable, I know I don't need digital servos and I don't think they need to be metal geared as the model isn't very big. What would you guys advise? I do have a load of HXT900 MICRO SERVO 1.6KG / 0.12SEC / 9.8G and I do have two CORONA CS238MG METAL GEAR SERVO 4.6KG / 0.14SEC / 22G which I could remove from another model. I'd like to get the covering on sooner rather than later as my new model will be arriving any time now so want to get started on that.
  14. Yesterday
  15. With some decals on.. Panel lines and some weathering to follow as well as the exhaust paintings..
  16. And of course, if I’m not on my own I don’t need to do it…
  17. Try something like setting a logical switch to a>x Thr -80 AND switch SCv then use this as the switch controlling the 10% mix. The rudder will then only be mixed in if the throttle is advanced far enough that reducing the output by 10% will not stop the engine. Mike
  18. I think if in the outputs menu you set the lower limit you want not to go beyond it should respect that, I stand to be corrected as I haven't used Open TX for a few years but that would certainly work in Ethos essentially written by one of the ex Open TX developers (Bertrand), worth trying though.
  19. Watching these posts with interest as I should be picking mine up tomorrow.
  20. You need continuous cast bar, most of the usual suppliers sell it. M Machine, Noggin end, College etc.
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