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vk3auu

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  1. vk3auu
    Performance There is something else you need to take into account too. When you read the manufacturers figures, take most of them with a grain of salt. For instance, one popular aircraft is being advertised as cruising at 80 knots at a fuel burn of 10.5 litres per hour. I would suggest that is a bit on the optimistic side. I'm sorry to say this, but there seems to be a few used car salesmen out there. David
  2. vk3auu
    Accident statistics The RAAus office has all the information about the number of aircraft and the number of hours flown, so it should be a simple matter to see if the accident rate is increasing or not. I might suggest that the numbers should be divided into two groups as well. Those aircraft which the traditionalists might refer to as "Real Ultralights" and those others. Perhaps a division based on nominal cruise speed and/or MTOW might apply. From a casual observation, it is my impression that the Real Ultralights are not the ones having the accidents, at least not the fatal ones. David
  3. vk3auu
    Bolt elongation Doesn't sound like the sort of thing that should happen to a good hi-tensile bolt. I wonder how many other elongated bolts there are out there?
  4. vk3auu
    Perhaps Poteroo and Brentc might have pointed at one of the problems. It may be to do with the inability of pilots to safely complete engine out landings into hostile terrain without causing themselves too much damage. They may be forgetting to apply the first instruction that should be applied in an emergency. FLY THE PLANE and in this case, fly the plane right to the ground and aim for the least bad obstacle. For instance, up in the top end of the Northern Territory, new chums were told, "Aim between two trees". That way you expected to leave the wings containing the fuel behind and the result would be milder deceleration. Forget about trying to save the plane. Of course, none of this should happen if we observe the rule of always looking for places to land as we fly across the countryside, but with the advent of the more reliable four stroke motors, this seems to have been forgotten. However, it also seems that quite a few fatal landing accidents also happen in comparatively good country, so some pilots may have forgotten to fly the plane because they have been distracted or panic set in. That is why we should practice engine out landings onto good airstrips so that if the time comes for the real thing, we don't get caught trying to do something for which we are incompetent. David
  5. vk3auu
    Elevator authority with forward CoG Arthur (pylon500) made a point about the difficulty flaring in the 912 Lightwing because of the forward CoG. I originally had that trouble in my '701 until I moved the battery back a bit, but it still wasn't too good with more than half flaps. If I carried a bit of power into the flare it was OK, but that wasn't always desirable with a short strip. Before my last trip to Narromine, I removed the slats from the wing leading edge and put vortex generators from John Gilpin along the top of each wing. I also put a row of them under the elevator and now I can pull it right up into a proper stall with full flaps and power at idle. I know the Lighty has a different elevator profile to the '701, as I recall it is a bit like the Thruster, but a row of VG's underneath right on the leading edge of the elevator might just do the trick. They need to go at the very lowest point when the elevator is at the end of its upmost travel. David
  6. vk3auu
    Oil tank behind seat. My '701 has a second hand 912 which originally came out of a Lightwing with the oil tank behind the seat. The sheila who owned it had a habit of starting it up and blasting off without waiting for the oil to warm up. Owing to the fact that the cold oil was still quite viscous, the engine was not getting good lubrication so it seized a big end and bent a rod. I got it from Bert after they had repaired it, but she managed to do the same thing about 12 hours later in another engine. The lesson to be learned is make sure that the diameter of these long oil lines is sufficient and also make sure you wait until the temperature comes up before you give it too many revs. David
  7. vk3auu
    Wheel landings In the Thruster I used to find that two wheel landings were better into the short field I have. I tried to keep the tail up as long as possible. If I had to go around, that was a better attitude to do it. If the fence was coming up too quickly a quick blip of the throttle and stab on the right rudder instantly produced a controlled ground loop and it slid to a stop sideways. No brakes so you had to be a bit creative. If the tail was down on the ground it didn't have quite the same effect. David
  8. vk3auu
    Cross wind landings If you adopt the upwind wing low technique, you will already be lined up with the centreline on your approach and you won't have to make that decision. All you have to do then, is flare at the appropriate height, plant the upwind leg, then gently lower the downwind leg and finally the nose wheel (or the tail if you are in a real aeroplane). That was how I learned in a Thruster and I had to learn how to do it to go solo because the late afternoon sea breeze was always at 45 degrees to one or the other of the available runways. Incidentally, with the low wing technique, you always know that you have enough rudder authority before you are committed to continuing the landing as the cross wind generally gets a bit less as you get closer to the ground. If your instructor isn't happy with that, find another instructor. David
  9. vk3auu
    RAAus & SAAA Andy, There are many people who are members of both organisations. Some would like to be but because of financial constraints only belong to one. Having one organisation to service the combined membership of both would have a great financial benefit, particularly in management and magazine costs. It would also enable the larger organisation to provide more and better services to the members. It would give us a better opportunity to lobby governments. I believe that the RAAus would benefit from the additional technical expertise which is available from many SAAA members and the SAAA would benefit from the greater managerial clout of the RAAus. These combined attributes will become more apparent if and when we get the 750 kg (or whatever) weight limit as a large number SAAA aircraft will fall into that category. I would like to hear arguments to the contrary, based on logic and not emotion. The time has come to bury any past animosities which a few years ago, stood in the way of such a move. David
  10. vk3auu
    Coloured paper I am with you Allan. I have been complaining for years about all the fancy coloured layouts in various magazines. They should fire all the graphic artists and get back to basics. David
  11. vk3auu
    Jets Darryl, for those of us who are not completely up with it, can you give us a more detailed interpretation of the two graphs. My impression is that Brent should be using at least 22 litres. My 80 HP 912 uses around 17 litres at about 70 percent power. I worry when I see people claiming very low fuel consumption. Ian Borg says " My personal opinion is to listen to the manufacturers and their experts". Unfortunately, they don't seem to be experts. Sorry. David
  12. vk3auu
    Emailing Magazine. I am not suggesting that email should be the only way to receive the mag. It should always be optional as the printed magazine has to be available for those without the email facility as well as to the newsagents. It does cost a lot of money to print and mail it and this cost could be saved. David
  13. vk3auu
    RAAus direction Adam, your question is very timely. I believe Paul Middleton is soon to retire so that the new Supremo will need to be carefully chosen and the path down which we go moves in a similar direction. I would also prefer the RAAus and the SAAA to become more closely involved. This would not have been possible a few years ago, but moves in that direction would probably be more successful now. We also need to give some consideration to distributing the magazine electronically, something which Paul has opposed. That might free up some funds for other services for members. Keep asking questions, they get people to think. David
  14. vk3auu
    Heretic And a bloody good one too Tony.
  15. vk3auu
    GPS audible warnings Does anyone know of any GPS's that have a jack on them to take the audio for the warning beeps out of them so you can then plug it into an intercom? Having audible warnings is pretty useless in an aeroplane if you can't hear them which I find is generally the case with a set of cans over your ears. David
  16. vk3auu
    Bearing tester The bearing tester mentioned is basically a dial gauge which sits in a fitting which screws into a plug hole. There is also a small pump which can suck the piston up and down when it is placed at top dead centre without the crankshaft moving. The dial gauge then measures the total play in the little and big end bearings.
  17. vk3auu
    I'll also re-jet to the new richer (23 lph) needle which will apparently give me a knot or 2 at the top end. That's what I like to hear. Do you notice the difference in the frequency of the noise with the three blade against the two. I flew to Narromine with a two blade and after flying with a three blade for several years, it sounded strange.
  18. vk3auu

    Jabiru sp 2200

    vk3auu replied to a topic in Jabiru

    Don't you beggars like flying? David
  19. vk3auu
    Sabre, I am not too sure whether we use the same terminology, but the word "wrench" means a shifting spanner in my language and you should not use one around an aeroplane. Have a good look at the Savannah, the latests kits are very good with most holes pre-drilled. David Zenair CH701:;)8:
  20. vk3auu
    I believe in the KISS principle. Use a dip stick. After you have flown cross country for a few hours you should know how much fuel your engine will use at various revs. Incidentally, don't fall into the trap that Jabiru did of tuning the carby to run very lean to save a bit of fuel. Nasty things can happen, particularly to air cooled engines when treated that way. Better to run a little cooler with the mixture a bit richer, it is cheaper in the long run.
  21. vk3auu
    As I recall, the regulations specify a particular lock which costs around $50. I have a $6 bicycle lock and integral cable obtained from one of the big hardware chain stores, wrapped around the propellor with a bright red sock saying "Remove before flight" David Tanner
  22. vk3auu
    I have brought this matter to the attention of the RAA but nothing has been done yet. I have a Zenair CH701 which as most people know is the aircraft that the Savannah has been copied from. A problem has developed around the upper brackets which attach the rudder to the fuselage' There are two extrusions which are attached to the rudder by 5/32" rivets, four at the top and four at the bottom. After a few years of operation, nearly always on grass strips, these rivets have worked loose, so I drilled them out and replaced them with 3/16 inch bolts. At Narromine a couple of years ago, I inspected all the CH701 and Savannah aircraft. The rivets on a CH701 had almost pulled out on one side and the owner replaced them before he flew home. Several of the Savannahs showed signs that the rivets were starting to loosen as the paint was starting to show a small crack. The same method of construction is used on the Zenair CH601 series. The problem is caused by the fact that these rivets are in tension and good design says that this type of rivet should only be used in shear. Please have a look at this part of your aircraft carefully and rectify any problems. Don't just replace the rivets with more rivets, use bolts. David Tanner CH701 19-1877
  23. vk3auu
    Does anyone know when Tony Witlox's funeral is?
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