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Yenn

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Everything posted by Yenn

  1. Yenn
    The reason the Aussies made decisions and the Poms didn’t is because the Poms would not allow lower ranks to think. They were there to do what the higher ranks decided. I speak from experience.
  2. Yenn
    Wasn’t Clive James part of the group looking for WMD, he was as sure they existed as GWB. He wasn’t the bright spark he was made out to be. His predecessor knew they weren’t there as did blind Freddy.
  3. Yenn
    Most aircraft have Loctite as a requirement in their maintenance. The strongest grades will allow you to shear off the bolt, unless you use heat. Others can be applied after torquing up and will wick into and hold the thread. I have heard of someone using Loctite, wicking grade (296 I think) to seal a riveted fuel tank, instead of Proseal.
  4. Yenn
    If a lockwired nut came off it would have been incorrectly wired. The object of the lock wire is to prevent the nut turning. It has to be applied with rotation in mind.
  5. Yenn
    South of the border.
  6. Yenn
    The Jabiru adjustable mixture carbide was I think either a hoax or just stupidity. I tried to see how it worked and it seemed to be able to lean out a rich mixture, so you had to start with a rich mix. I phoned Jabiru and the personI talked to had no knowledge of it.
  7. Yenn
    How is the octane rating changed by leaning?
  8. Yenn
    Rich of peak is producing more heat than lean of peak. That increases CHT. How to alter mixture depends upon the aircraft, in mine it is by a push - pull control. Normally you would take off full rich, except at high altitude airstrips. You would not touch the mixture until after you reduced throttle, then you could lean, while watching the EGT and look for the peak temp. The lean until it dropped about 75deg. I find it easier to pull the mixture back quickly until I hear the engine run rough and then increase flow to make it smooth. The EGT when it is smooth is then what I aim for at any other rpm.
  9. Yenn
    Yes an over lean mixture could burn valves. What I should have said was that running on the rich side of peak EGT means you will run hot, resulting in higher CHT.
  10. Yenn
    What you use will depend on where you are. My home field has very hard, dry soil. Best bet is a short length of star picket. one way to lessen the uplift is to have something on the wing, just ahead of the deepest section, to stall the wings lift. It doesn’t take much, a length of thick rope.
  11. Yenn
    All well and good to say if you want to live in the bush, cut firebreaks, but we are governed by bureaucrats, who know far better than we do, all about safety. We have to get their permission to do anything, so it doesn’t get done.
  12. Yenn
    All the disadvantages of an ic engine and electric combined.
  13. Yenn
    What I was taught was incorrect, but I found that out much later. For best leaning methods you need EGT gauges and fuel flow for even better usage. Normally full rich would be used for takeoff, then lean as necessary to keep the EGTs at what you saw at about 1000’ on climb. At cruise you pull the mixture well back until the engine runs rough and then richen the mixture to smooth. The EGT reading then is just about your target. Lycoming preach that you should run on the rich side of peak EGT, but that in my opinion is wrong, it is where you are likely to burn valves. Lean on the ground when taxing, but lean aggressively, so that the engine will not run with the throttle being advanced, that way you will not oil your plugs and also will not be able to take off without advancing the fuel flow. If you have fuel flow metering you will be able to use the mixture control more precisely with experience of your engine. Th one thing to be aware of is do not lean out at anything more than 75% power, to avoid detonation.
  14. Yenn
    I am away in Victoria for a break and will look at the survey when I get home. I believe it is no good whinging unless you are prepared to say why you disagree and I can’t be bothered now. I wish you all a Merry Christmas.
  15. Yenn
    This was not really what CASA would define as a bulk strip. It was repairs to camshaft and no doubt followers. There is no need for rings to be replaced. It is possible to pull the cylinders and pistons off without disassembling them, therefore no need to re ring. But that would not happen with a bulk strip.
  16. Yenn
    SAAA have today published their response to the consultation paper. It is obvious that RAAus has severely pissed off the people at SAAA. They have come up with a well detailed reasoning that RAAus is not trying to improve safety, but only wants to have a monopoly. While RAAus has a lower medical requirement and also a monopoly, with CASA not approving any other body to run sport aviation, SAAA is saying that there will be no safety benefit, but RAAus will get an even greater cash flow. All at the expense of pilots who have had better training. I won't post the response as I am not sure it was intended for non members, but you may be able to find it on the SAAA web site. As usual it is a well thought document, unlike some I have seen from AOPA.
  17. Yenn
    My understanding is that a bulk strip could be done just because the engine is of a certain age. CASA require a bulk strip of old engines because there is deterioration of seals and other things, due to age rather than wear. I guess that this may be an old engine, which has not been used all that much. I would assume that the condition of the bores would have been checked during the bulk strip, but not necessarily for wear, just visible corrosion, also the camshaft. It is probably a Lycoming and one of the common failure points for them is the camshaft. It would be bad practice to return to service an engine with corrosion on the cams, but I don't know if there is any guarantee. I would suggest that you read the engine logbook, which should detail work done. Maybe even talk to the maintenance organisation.
  18. Yenn
    Back to Boeing. I hear that they have only just stopped manufacture of the Max and have 400 sitting in storage. They don't seem to be getting any nearer to solving the basic problem, FAA has had its nose put out of joint and Boeing are proving to be arrogant. They consider they are above scrutiny. I would not like to bet on all those aircraft ever finding buyers. In the meantime Airbus are looking good, I never considered them to be as safe as Boeing but that was a mistaken outlook. Airbus seem to be more comfortable from the passenger point of view, also quieter. Qantas are looking more and more to Airbus for its future fleet. I don't think I will be buying Boeing shares even if they do drop to affordable levels.
  19. Yenn
    I agree with the comments about the observability of lights on RAAus aircraft, but that wasn't the question. In my opinion you need to have witches and fuses for all systems. If you want every light on at the same time, then one switch will work, but if you want strobes, wingtip lights and landing lights, then you will need more switches. You may also want to put in a connector at the fuse to wing joint, in case yo ever need to remove a wing.
  20. Yenn
    We seem to have gone from building using welded joints instead of the usual, to repairing in the field. I don't think I would want to use a field repair to get home if it was of dubious quality. OK maybe for a car or even a boat, but not for a plane. I hadn't realised that Nev had a concern that we didn't tell him whether we found his posts good or not. I must admit that you seem to know what you are talking about Nev, I value your posts as I do for OME.
  21. Yenn
    The Jab design is basically two plenums, one for each side. The pipe between them is only attempting to even up the pressure in each plenum. The difference between the Jab method and a Lycoming for example is that the plenums are smaller and there is a lot of cylinder which does not get ducted air, plus there is air escaping between the fins and the plenum and also as I noticed this morning when I looked at my setup, it is possible for air to escape beneath the plenum and out between the rocker boxes. If I was trying to get the max cooling I would blank off between the rocker boxes and duct air down between the sides of them. I have only just seen Pauls contribution above, looks good and what I am suggesting is the same again on the outside.
  22. Yenn
    For those landing downwind the biggest difference in the approach is going to be the much flatter angle of descent. I know most off us do not use a 3 deg. approach, but usually a certain sink rate. the difference between a 5 kt headwind and a 5 kt tailwind is quite dramatic. Add in a bit of drizzly rain and you can be easily deceived.
  23. Yenn
    It wasn't just in olden days that people imported bad agricultural products. A few years ago the citrus orchards around Emerald were completely removed because someone had imported superior stock from overseas. It was infected. Fire blight, an apple disease was found in a botanical garden in Melbourne. The Kiwis have for years been trying to send apples to us and Fire Blight has been the reason their importation was not allowed. Funny thing the diseased material in Melbourne was found by a Kiwi. Equally funny, nobody else could find any trace of it, in the garden or elsewhere. The supermarkets have been allowed to import cheap prawns form overseas. That caused the complete failure of the prawn industry in NSW because of white spot disease.
  24. Yenn
    Meanwhile. What happened to the plane from Shellharbour?
  25. Yenn
    I fail to see how copper coating of the fins can have any effect on cooling. The aluminium fins get to X degrees due to the heat of combustion. Without plating they are in contact with the air and give up their heat. Copper coat them and they are in contact with the copper, which gives up its heat to the air. The only possibility that there could be any improvement is if the layer of oxidised aluminium is acting as an insulator. What really matters is getting the maximum amount of air to contact the maximum area of fin. To do that you need ducting touching the top of the fins, to make the area between each fin into a duct for cooling air, Carry the ducting around the fins, leaving only enough room for the air to exit.
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