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Evan Pimm 2

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Everything posted by Evan Pimm 2

  1. It usually turns out to be whatever you find the most comfortable, and for most, whatever  mode your instructor taught. Evan. 
  2. Nick, your ideas are all sound, and I did indeed simply top hinge the ailerons. `Pull-pull' for the rudder will work just fine, a servo at the back may be ok, but I put mine all in the wing area and needed no ballast, so go easy on putting anything behind the cg. Those old drawings showing the original Friese type ailerons  (also shown on the original Orion plans) were an attempt to combat adverse yaw problems, but these days we have Tx mixing, and I had no yaw problems with the model anyway.  A servo in each wing will be fine, but very `modern'  for the old girl. Evan. 
  3. If you get the chance, have a look up the real things legs (, where you will find just a simple hinge (pintle). No twisting or turning. What you have to do is to angle the retract pivot axis of your ordinary retracts to the same angle as the original. One part of this angle is at 90 deg to the plan view of the leg axis, as in the picture, and the other is at 90 deg to the leg axis in the side view with the leg down. What it means is that the retract rails will be at a strange angle in the wing. Why is it like this? So the wheels can retract into the wing without fouling the main spar. Set up the wheel axis straight on the ground and the wheels will fit into the wing just like the real thing. Evan. 
  4. And since the back of the blade does the work always remove the material from the front (curved) side of the blade.  Removing material from the back of the blade could affect the pitch of that blade, and you should see what that does to the dynamic balance at 10,000 rpm. All props should be balanced, even liquorice ones, as I have yet to meet a mass produced prop that is in balance `as purchased'.  Wooden ones are the worst, and as a brand `Master' (Windsor)  tend to be the worst of the lot. FWIW. Evan. 
  5. Or you can clean up the faces of the muffler and exhaust (carefully, with big, flat, fine file and lots of stuffing the the exhaust outlet) and put it back together. The reason that many manufacturers don't use a gasket is cost (of course) but the added benefit of no gasket is better heat transfer across the engine/muffler join and therefore better cooling of the head at the hottest point. Even if the engine is cowled the muffler is usually out in the breeze, so this cooling effect should not be dismissed. Evan. 
  6. Yes, the red one is the idle stop screw. If you want to stop the engine from the tranny you will have to screw it out far enough that the engine will actually stop with the throttle stick right back and the trim also right back. Some experimentation will be required. Evan. 
  7. Nah, it's actually the blades cutting through the wake turbulance off the trailing edge of the wing or slot in front. Even if you have a pusher mounted on a pylon over the wing the turbulence off the strut/s will have the same effect. Tractor props don't usually have bits of airframe in front of them... Evan 
  8. Just some thin resin all round the engine bay, fuel tank area, and anywhere the exhaust will blow down the fuselage. You don't need much on the outside, just a bit rubbed into the wood and sanded smooth before covering. Use plenty elsewhere as you're bound to get a tank leak, split fuel line etc at some time and it's just good insurance. Evan. 
  9. Nick, the `Aeromodeller' plan is still available (X plans list?) and has all the info you need to build an original. Take care with the Sig kit, replace wood as necessary, remove all the `lite ply' and use the A-M plan as a guide for replacement items. Sand it lots when complete and use plenty of epoxy around the front end to keep the oil out and you will have a model to enjoy for many years to come.    Evan.  
  10. The corrosion is due to the hygroscopic properties of the fuel (Methanol). It will happen in any engine that is rested for any length of time with fuel residue in the crankcase. The prevention is well known, at the end of each flying session remove the fuel supply with the engine hot, running at a fast idle and with the plug igniter attached. This will help to scavenge most of the remaining fuel. At home a few drops of Auto Trans oil or some other moisture dispersant oil (air tool oil, for example) flicked through to coat the insides, then hang the model nose up so that any crap will drain to the backplate where it can do little damage will see the bearings last long enough to require replacement due to wear, rather than corrosion. Evan.
  11. Nick, The original (Dunn) was the same scheme (Sunburst) as the red and white one you know, only it was black and white. First flown in 1957 at the LARKS flying site in LA. So far as the photographic record shows, all the others (Dunham, Nelson, et-al) were modified in some way and the colour schemes proliferated. I have a mate who was there as a teen at the time, helped Bob Dunham after school assembling `Orbit' rigs in the back of Bobs model shop, and he still says it was the most interesting time he's had in aeromodelling. Seems all the West Coast greats were in that club at about the same time and that's when R/C really took off, if you'll pardon the pun. So really you can just go for it, Flash Gordon was alive and well, so was Superman... Evan.
  12. Nick, It all depends on whether you can get it to balance. Any 4S from .45 up to, say, .70 will be ample power, the limits will be engine weight and how far you can move the flight battery to compensate. As for the noise thing, there isn't much difference between a 2S and 4S, only the perception of the listener. As for models we would like to build, well there comes a time when you realise that you are gunna havta live considerably longer than most, and with all your faculties intact... Evan.
  13. Cor Nick, thats heaps of questions, but having built a `Berkley' clone with help from the `Aeromodeller' drawing for some of the sections, I will attempt to answer some of them. The mods done were only for the use of modern gear, so the removeable top was made fixed. Keep the tank hatch as drawn, it's quite useful for maintenance. The tailplane was fixed, using the external doublers as a fairing, and I added a bit more incidence (L/E up) to give about 1 deg diff. between wing and tail, we have elevator trim now, you see. The dihedral braces were extended out to the outboard end of the L/G blocks and the blocks themselves scarfed at the centre, and glued to the ply brace, really strong. The rear braces were extended only one extra rib bay. The balsa spars are more than adequate, don't change them. I used 5/32 wire for the L/G instead of the two bits of 1/8 as shown on the plan. Otherwise it was built`as per'. I use a 1/8 ally engine plate and just make up another one for whatever engine I'm using in it at the time. As for power, anything from an old FP.40 to a K&B .60 has been used, gentle with the .40 and grossly overpowered with the .60. As a guide the flying weight with a TT.46 was 5.5lb and it would do the full 1970's schedule with it, so it don't need a lot of power to do the necessary. As for radio stuff, I use one servo in the centre with old fashioned bellcranks etc, but it's up to you. Keep it a tail dragger, it's lighter and better for you, it really is a lady on the ground but it will help with learning to use the rudder for torque control. Flaps definitely not required, nor strip ailerons, and the Sig version has the tailplane in the wrong place, looks all out of shape. It is an old fashioned airplane, but if you build it straight, with perhaps just a smidgeon of washout, you will discover that there are lots of models out there that could do with a bit (lots?) of what this model has. I use mine as an `ab initio' trainer these days and it still teaches them quicker than any of the modern high wing ARF boxes. We have not learnt much in the last 40 odd years... Evan.
  14. I don't know of a better engine for the price, I have 3 of the things and while they don't have quite the same power as an OS they are of the same build quality and exhibit the same impeccable handling manners.I have only nice things to say about them. Evan.
  15. Solarfilm make a proper paint system for their films, if your LHS sells film then they should have the primer and paint as well. Evan.
  16. Thats funny, on my JR it's +ve. Whatever, what you are looking for is less surface movement for the same stick movement around neutral than at the extremities of movement. Dial in about 50% expo with the dual rate/expo switch in the `1' position. Turn on the model. Return the switch to the `0' position and move the surface just a little. Now move the switch to the `1' position. If the surface moves back toward neutral then you have the expo you are looking for. If the surface moves away from neutral then you will need to put in the opposite sign expo. Around 30% expo will give approx. linear surface/stick movement with a rotary output servo. Try flying the model with this amount before doing any further experimentation, as this will often feel more comfortable than before, and more expo may leave you with the feeling that the model is too sluggish around neutral, and too responsive as you move the stick more, to make up for the apparent lack of control around neutral. Always do this switch check before you fly, along with full, free and correct sense, to avoid surprises when flying. Evan.
  17. Timbo, Thats what Sanyo say. But I think the thing is that we are confusing a full charge voltage when what we really mean is full charge capacity. As our radios generally give a voltage indication only, we tend to use that as an indication of capacity. The two are not (of course) the same. Both my 3810 and 9x2 have both voltage and a capacity remaining indication, but really the only way to know the state of your batteries is to use one of those modern chargers with an `amps in/amps out' cycle and do the occasional charge/discharge cycle and compare what's coming out with the rated capacity of your pack. I will scrap any pack giving me less than 75% of the rated capacity. Really, so long as the pack is delivering the stated capacity with a good load on it, then the volts don't matter. Evan.
  18. Actually, according to the manufacturers, a fully charged Nicd/Nimh cell is 1.2V. 9.6v is the nominal full charge voltage of an 8 cell battery pack. Thats why most servos are rated at 4.8v, this being the nominal fully charged voltage of a 4 cell flight pack. The fact that we get higher voltages from our packs does not mean that anything below 10v is dangerous, the radios will work down to 7v at least. My JR has an auto cutout at around 8.9v, and a fully discharged cell will read 1.1v, so a full discharged 8 cell pack will read 8.8v. Evan.
  19. Considering that 9.6v is nominal full charge voltage, and it's still over that after an hours running, I don't see you have a problem... Evan.
  20. A good dope and tissue finish will always beat a good film finish provided that you use a good paint system to keep the oil out of the wood. In these modern times might I suggest a good two pot paint, applied by your friendly car refinisher, who will enjoy the change of pace, as probably the most efficient way of painting/sealing the model. Evan.
  21. I remember reading that very article just recently, sort of comparison back to back test, cause Bob had just left his Thunderbird in England at the end of his world tour promoting aeromodelling and C/L too. That sort of thing don't happen any more...unless we can come up with some other way of flying a model airplane. Evan.
  22. I would do it the other way around, make sure the film is attached around the edges first, otherwise shrinking it might not get the wrinkles out at all... Evan
  23. Hope we're not usurping a possible RCM&E series... Evan.
  24. I have only seen a small grainy b&w in an old `Aeromodeller' so I can't comment, but didn't he base it on the F.W 190? Evan.
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