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John Stainforth

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Everything posted by John Stainforth

  1. Do unto Saito that which is Saito's (advice); do unto Lasers that which is Jon's.
  2. Yes. They even built a wind tunnel (I believe the very first) to test various airfoil sections. It is remarkable what they achieved, virtually from scratch, simply by experimentation and trial and error. They did not build their powered flyer until they had worked at the basics and a way of steering ("wing warping") by making numerous manned flights with several gliders over about four years.
  3. This is not CA, which is cyanoacrylate, but it could be an isocyanate. The problem is that this is a vague, abbreviated chemical description - e.g., "aliphatic" applies to any paraffinic straight chain. I would be somewhat worried, though, about the xylene and acetone (which are specific compounds): These are very strong solvents, so you definitely should test spray this over the paint coat you want to proof to check that it is not attacked.
  4. I am proud to be amongst these dinosaurs. Just remember: birds are reptiles too and are unsurpassed at flight.
  5. Well, I did once have a pistol pointed straight at me, at point blank range, by a policewoman in Texas when I got stopped because I had a defective rear light.
  6. I had a tire blow out on my Toyota Prius a few years ago in Texas. I had parked it on black tarmac in the midsummer, midday sun for about half an hour. When I drove off the car rapidly developed a repetitive bumping sound, as though something was stuck in one of the tires, and the car was rising up and down slightly as though what was stuck was protuding downwards. I stopped the car, and had a good look round and could see nothing stuck in any of the tires. So I drove off again and hadn't gone more than a few hundred yards when then was an explosion - a very loud bang, and the car immediately slumped down on one side. A tire had blown out completely - there was a flap about four inches in diameter hanging out from the inner side wall. I put on the spare tire, and took the car straight to the local Toyota garage and they said they had never seen a blown tire quite like that. Incidentally, I had just had the car serviced before this happened, so I think the tires may also have been overinflated before I parked the car on the black tarmac.
  7. That's explained by Relativity. The size of the bread is too big, relative to the toaster.
  8. This subject of castor is so worn it could probably do with some castor itself, to gum it up before being thrown away!
  9. Beautiful build. If you put celly thinner in the Klass Kote, I am surprised it worked at all!
  10. One thing to be careful about, if you go back to 35 MHz, is to remember to pull the TX aerial out. (How do I know?!)
  11. I found foam rollers work best for applying the first coat of resin, rather than credit cards, supplemented with foam wedges for jabbing resin into corners etc. It is not necessary to seal the wood first, but it should be sanded really smooth and imperfections filled with filler before applying the glass. The first coat of resin, rolled through the glass, should be just enough to stick the fibreglass down to the wood. Most people apply a second or "flow" coat of resin (rather than a filler) and this should just fill the weave, but no more. I found a one-inch brush most satisfactory for this second coat of epoxy resin. (I suspect that quite a lot of the variations in technique are a matter of personal taste.) The really heavy lifting is in the sanding after each coat has dried. Then the primer for the paint is applied - best to use a compatible epoxy primer rather than a car primer; then more sanding; then the paint coat(s).
  12. I confess that I am not familiar with the fine details of the final rules that have not yet been implemented, but this does not sound too onerous, since most current AMA model flying sites will be classified as FRIAs.
  13. We live in difficult times and the overall intention of this registration is benign and not a significant cost. I think it helps to increase the respectability of our hobby. BTW, the registration process with the FAA in America is not more onerous - it is more or less identical. (As I predicted, we have more or less copied the American process, with a lag of a few years. This not surprising: most rules around aviation are pretty similar in the whole western world.) One difference: registration was adopted by modellers there with very little fuss, although there was a lot of discussion and angst before it came into law, because at one time it looked as though the constraints on aeromodelling were going to be much greater. Overall, the US government is rather in favour of aeromodelling, because they see it as a potential recruitment vehicle for the aviation industry and the Air Force. (Remember, the likes of Neil Armstrong, and Rutan started as aeromodellers.).
  14. With 3D CAD, I've found what works best for me is to record everything I do as I go along. This way I have gradually built up my own manual of the best ways of doing each kind of task.
  15. Thanks for the explanation. Most plastics are great in tension, but not so good when bent back and forth repetitively. That's the way I destroy my old bank cards. Even mylar hinges eventually crack up as a result of this bending. I imagine the film method is only really OK for small models, but I could well be wrong.
  16. Please can someone enlighten me as to what is meant by a "film" hinge. A film is just a thin layer. But what are the recommended materials (type of plastic?) and thicknesses? Surely these are crucial factors as to how well these work as hinges and how long they might last?
  17. Fracking won't do it. The potential for shale gas in the UK has been greatly exaggerated.
  18. Have you fully tuned the engine, i.e., both high speed and low speed needles? Generally, the low-speed settings have to be leaned out a very long way from the factory settings.
  19. I apologise: I had no idea that your official recommendation was not to use hopper tanks. The hopper tank system is not the least bit random, but it is confusing. This is why it has to be thoroughly checked out on the bench. All I was advocating was trying this out first, before putting a saw to a model airframe. I have only used the hopper system once in a model, which had an unimpressive structure (i.e., weak looking), so the last thing I wanted to do was to start removing parts of that rather inadequate looking structure to accommodate the tank. BTW, I did not dream up a hopper system: I used a very useful sketch that was provided by someone on this forum, and found that their set-up worked remarkable well - even though (it has to be confessed) it was quite difficult to see how it was working with the engine running! I highly appreciate your expert views and have been careful to place the tanks generally as you have suggested. I have found (as you say) that it is essential with Lasers not to have the tank too high; but rather low doesn't seem to present problems. (In my S6b, the tanks are slightly low, but I tested the running of the engine with the tanks in that position, very thoroughly on the bench, before committing the rather low position to the design.) My own approach is to test thoroughly first, cut later.
  20. Personally, I would try the plumbing octopus first, before hacking away at an airframe to accommodate a very low tank position. I have manage to get a "chicken hopper" system to work well. It's not that difficult to get the whole thing thoroughly checked out and tested on a test bench before installing it in the plane.
  21. The air flowing backwards from the wing does not follow the flight line exactly, but is deflected downwards by the (positive AoA of the) wing. This is the so-called "downwash". So, relative to the deflected air, the AoA of the tailplane (horizontal stab) is slightly negative; hence, the tailplane is generating slightly negative lift.
  22. The six different Saitos I have (from 72 to 180) have different strokes, so I expect the con-rods are generally of different lengths, even if this is rather subtle - hence perhaps a need to differentiate them in other ways.
  23. Does that preclude a mark on the other side? Also, could it be that conrods for different Saito engines are marked in different ways so that they don't get put into the wrong engines!
  24. I thought the consensus was that this mark was cosmetic, because it sanded out. Is it not possible that it is a deliberate mark to ensure the con-rod is mounted the right way, or to assist with the timing alignment?
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