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rotax618

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  1. rotax618

    520 kg vs 560 kg

    rotax618 replied to g2omer's topic in Savannah

    The RAA will not change the max TO weight from the original registration even though you produce a the documentation and photographs and WB of the modifications, at least they wouldnt for me.
  2. rotax618
    Unfortunately the venting of the tank will also effect the measured pressure, my Sav has forward facing fuel cap vents, they increase the air pressure in the tank. Years ago I built a capacitive fuel gauge for my Drifter using two sheets of copper clad circuit board screwed together with nylon screws and separated by thin nylon washers. I measured the capacity with a Dick Smith kit. It worked OK most of the time but because of the change of chemical content and moisture in the fuel the gauge had to be set for the amount of fuel before each flight.
  3. rotax618
    2:1 is a very bad ratio, needs to be an uneven number or the same gear teeth take all of the power pulses and will soon fail. Ther was a CAM drive Honda with a 2:1 ratio, didn’t last too long.
  4. rotax618
    Three hinges on a door is always a problem, as the door warps the centre hinge always becomes loose, the elevator hinges on the Sav probably suffer misalignment under load. ICP should offer a repair method if this is a problem on high hour aircraft.
  5. rotax618
    The point where the splitpin hole is drilled has no load, the load is inboard of that point, the nut is only a retainer for the bush. The highest shear load is where the pin is welded to the flange, if there is no sign of cracking or bending there then the fitting is safe.
  6. rotax618
    3mm is unnecessary, the success of an aircraft is not what you can add but what unnecessary stuff you can eliminate. The designer of the Sav was careful to eliminate excess weight in the structure by using materials which have the necessary section modulus resist the loads that will be applied to the structure in all regimes of the Sav’s flight envelope plus a safety margin. In aircraft design it is easy to make something strong enough but it is clever to make something light enough.
  7. rotax618
    I replaced the 2mm windscreen on a friends Sav VG with a 3mm screen, The original screen couldn’t be used as a template because the thicker screen didn’t bend the same, you have to allow a larger margin and pull the screen into shape, mark and trim.
  8. rotax618
    It is bad design to have bending and shear loads on the threaded section of a bolt or fastener. The Bush Caddy rudder looks like another example of lazy design.
  9. rotax618
    That is possibly the heaviest hinge to use, and bad design to boot, there is no omniversal motion in the tail assembly. Have a look at what Mignet used. You only need brackets similar to what you have made for the tail post and a couple of AN3 bolts with bushes and castillated nuts. The 8 mm rod ends need 8 mm bolts, rather an overkill.
  10. rotax618
  11. rotax618
    Plan of the Stinger.
  12. rotax618
    Correct.
  13. rotax618
    How about this Delta.
  14. rotax618
    Cut the 30mm blue foam to rough shape with a hacksaw blade, shape with a sharp knife and sandpaper. Glue the foam to the tail tube frame with 5minute epoxy. Cut some strips of 5oz glass cloth on the bias. Paint the ribs with R180 epoxy resin, cover the ribs by wrapping 2 layers around the ribs and tubes, you need to fillet the edges of ribs so the glass cloth will conform to the shape. If you are going to ceconite cover the tails and paint them you need to fibreglass the ribs, the fibreglass packaging tape used on the sailcloth tails decomposes to dust in a couple of years.
  15. rotax618
    Was a Nelson 40HP, looked like a McCulloch.
  16. rotax618
    I used blue foam in the Boorabee tails, but I used fibreglass tape and epoxy resin to hold the ribs in plase and reinforce them, turned out very strong.
  17. rotax618
    The early Fishers used Dow Corning Blue extruded styrofoam. Later to make the tail stronger and make the fibs lessliable to break, Wayne used Divinicell or Klegecell PVC foam - can be quite pricey, if you can find a boatbuilder you may get an offcut.
  18. rotax618
    Professor Ed Lesher built the aircraft, it is a Lesher Teal. It was built to break FAI speed and distance records.
  19. rotax618
    Sorry to hear about your health Mark, it is a very serious disease, a neighbour of ours at Evans Head had to get a heart transplant as a result of complications from Qfeaver.
  20. rotax618
  21. rotax618
    Low aspect ratio planforms are not pitch sensitive they are generally stall proof and spin resistant, because of their inherent stability, they usually have no dihederal or anhederal to make them more sensitive in the roll plane. I suggest that turboplanner does some research before making those generalisations. The Arups, Milt Hatfield's Little Birds, Vought FXU5 and V173, David Rowe's UFO, Wainfan's Facetmobile - all exhibited positive stability - all were stall resistant, and all were reported as pleasurable to fly. The Helios and other electric powered aircraft have used the tractor configuration which provides the least turbulent air into the propellers. Unless the thrust can be vectored down, prop slipstream over the wing from the front is the best way to use the wing shape to increase lift, low aspect aircraft have wide chords and therefore large reynolds numbers, the same circulation over a wide chord gives a proportionall greater increase in lift.
  22. rotax618
    One design which could utilise the compact compact size of electric propulsion would be the Zimmerman flying flapjack, I propose that 4 motors be placed along the leading edge of the wing , 2 at the tip would revolve contrary to the tip vortices, lowering loss from induced drag. The slipstream from the props would provide a large proportion of the lift making it a superstol.
  23. rotax618
    Faceted aircraft can fly as shown in this Youtube video of an aircraft I designed some years ago, built and flown by Danny Leach. The video was taken on its maiden flight in blustery conditions, most of the landings were dead stick because we couldnt keep the engine running
  24. rotax618
    A plasticiser must be added to automotive paint, plasticisers are added to auto paint when it is to be used to paint flexible plastic parts. From my experience 2 pack auto paint gives a good finish to nitrate doped ceconite, but silver paste must be added to the dope to provide UV protection and the 2 pack paint doesnt adhere all that well to the silver dope surface. If the paint membrane is broken by hail, stones or hangar rash if can be peeled from the silver dope. Wayne Fisher used to paint the partly weathered drifter flying surfaces with "house paint" to prolong the life of the sailcloth.
  25. rotax618
    Its a Mk2 Boorabee like this one
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