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Ultralights

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Everything posted by Ultralights

  1. Ultralights
    the initiator to a spin is YAW. as long as your BALANCED, you can stall (exceed the critical AOA) and still recover as usual, just enough forward stick to reduce AOA below critical angle. regardless of amount of bank. practice a stall straight and level, and note the stick position, even at 30 deg, and 45 deg AOB, the stick will always be in the same position when you stall. i wouldn't recommend practicing it yourself though, get some proper EMT training, learn how to recover from stalls at all Angles of bank, and how to not get into a spin. and what to do if you find yourself suddenly upside down with the nose low. but a spin needs YAW. so keep the ball centred.. and resist the urge to tighten up the turn with rudder. even at steep angles of bank... keep balanced! if the nose starts to drop, roll off the bank, dont use the rudder!
  2. Ultralights
    i have just finished reading the latest edition of Kitplanes magazine out of the USA. a good 6 page story on keeping a Jabiru engine running reliably... they identified 2 main culprits for their failures. lack of oil cooling, and lack of airflow around the engine and heads. their first recommendation.. throw away the oil cooler! its useless apparently, on a Cub they found the best was the oil cooler from a 180Hp lycombing. and then you have to make sure it gets enough airflow, requiring a separate ducting system, that didn't increase the air pressure under the cowl and reduce head cooling. so the cooler was in a duct, with inlet at front of the cowl, and exit below the engine at the outlet at the bottom, no air allowed to flow into the engine bay area. good cooling over the heads was next, but also be aware of excess cooling on the fwd cylinders, fixed by a small air dam over the front cylinder fins. and third and final tip, run them hard. the last point i agree with, i have only had experience with the 2200 in a school environment, and the boss told us to run them hard, and they did go the distance. cruise at 2800 to 2900 rpm. but this was almost 6 yrs ago. so maybe temps are the issue over here, just we have been looking in the wrong area..
  3. Ultralights
    pulling back on the stick until stall, the stick position will be same, weather it be at 40 kts straight and level, or at 100kts pulling out of a dive, its called stall stick position...as tomo said, learn it and remember it , could save your life one day.
  4. Ultralights
    a lot less bad low cloud west of the divide..
  5. Ultralights
    exactly... EMT training should be mandatory.... even for Raaus.
  6. Ultralights
    oh no, i forgot, people can no longer die in this world, its especially illegal to die while doing something fun.... sorry, jusr a little rant after watching the background info vid... now, back to those reno airaces!
  7. Ultralights
    there is no real show to speak of, just a few routine displays throughout the day, aircraft coming and going all the time, if a display is on, you will be directed by unicom to hold approx 5 to 10 miles away. most, if not all that those who go to natfly for are on the ground. and in the aircraft parking areas. most activity during the day is aircraft departing and returning from demo/test flights.
  8. Ultralights
    So what's the minimum height for a Go-around? I have had ATC tell me to go around just after I have started the landing flare. They saw a dog running across the runway that I didn't. Was this illegal? Should I have landed as I was below a certain height above the runway?
  9. Ultralights
    stall speed is irrelevant when it comes to stalling, AOA is.
  10. Ultralights
    low speed, both wings have higher AOA, bank right, in a climbing turn, left upward wing, with downward aileron, now has a greater AOA then the right hand, lower wing, left wing stalls, start roll and yaw to left, reaction might be to add more left aileron, further increasing its effective AOA, deepening the stall, then rapid roll into spiral/spin to left.
  11. Ultralights
    that video was an incipient spin, not a fully developed spin. plenty of skipper aircraft at Camden. Liverpool flying club operates them, well, they did when i last was there last year.
  12. Ultralights
    in the rotax line maint manual, the front plugs being a dry black sooty, and rear ok, was a symptom of oil temp being to cool, this is how i found out, and sure enough, covered up 1/3 of oil cooler, oil temps now about 95 in cruise. all is well again. oil temps on cooler days were at about 70 deg before covering the cooler.
  13. Ultralights
    actually you can do both, over the top of a loop, easy to keep pulling, and hit critical AOA with positive G, or even flying inverted, push to0 far forward, and again you can hit the critical AOA, much harder though as the amount of forward elevator authority is usually a less then up elevator movement, but the reason for the stall is always the same, exceeding the wings critical AOA. and the simple way to unstall, is reduce that AOA.
  14. Ultralights
    i found with my 912, that a dry sooty powdery residue was caused by oil being to cool. but with mine, it was only the front 2 cylinders that were black and sooty, the rear were perfect colour.
  15. Ultralights
    as i said before, a stall is a function of AOA only... and only reducing the AOA will unstall the aircraft. 15 dg AOA, not stalled, still flying as usual. 16 deg AOA, stalled, either both wings, or one or the other, but get it back below 16 deg, not stalled. and you will only find that a small elevator movement is the difference between 15 and 16 deg AOA. no violent nose down push, just relax back pressure on the elevator, and you will unstall. with practice, you can stall and recover with only a height loss of less than 10 ft. pull back hard enough at Vne, and you will stall. even inverted.
  16. Ultralights
    nice demonstration of correct use of tool, i would have been sacked for doing most of that, even at qantas... tools such as shifting spanners, monkey wrenches are banned from my current workplace with military rotary wings.
  17. Ultralights
    i would bet a quite substantial amount of anything, that, if the case was redesigned, so it was held together by its own fasteners, like, well, pretty much every other airborne boxer piston engine, then the load on the fasteners holding against the combustion forces, and keeping the cylinder barrels attached, would last a great deal longer, i would say, to stated TBO quite easily.. and it would not be a difficult redesign of the case either, just a leave a half inch thick flange around each half... it appears to me, there simply isnt a bolt capable of doing what the single through bolts are being asked to do, 2 opposing cylinders, and crank case forces. to get a bolt to do that kind of work, and last. would require something made of a titanium or similar alloy.
  18. Ultralights
    i cant help but think, if the engine was designed better, then bolt breakage, stretching and other forms of fastener failure should never even be an issue. it sounds to me as 90% of the bolts load limits are reached when the engine isnt even running.
  19. Ultralights
    not sure, but the ones im always cleaning up are directly under the mass of spider webs on the hangar ceiling.
  20. Ultralights
    what about spider dropping, little tiny black dots.. absolute buggers of things to remove from white paint.
  21. Ultralights
    my closest encounter with a glider, 8500 ft above Lithgow, west of Sydney. i was tracking west, no idea where he was going, how could he maintain a hemispherical level operating up there? , no mention of traffic on the radio either. lot of IFR traffic departing bankstown heads that way as well.
  22. Ultralights
    dont forget, at most of those places, almost all of their customers dont return, so there is no real need to attract the return customer.
  23. Ultralights
    i have well over 1000 hrs, still find holding a perfect track a little hard sometimes. im happy if i can get about 10 deg or better for more than a few minutes.
  24. Ultralights
    when you look around, relax your grip on the stick, trust the trim to do its job, then when you look where your going again, you should find nothing has changed.
  25. Ultralights
    the spar is plenty strong enough. and im sure you will find it surprising to know that the robin aerobatic training aircraft only has 5 ribs along the wings entire length. the strength is in the skins. dont forget, in a braced high wing aircraft, the loads are shared by the lift strut, and by design, the loads are longitudinal along the spar to the wing root from the lift strut join at the spar. so the only 100% bending moment in the spar is from the lift strut join to the wing tip. the wing root mounts are under a compression force. Lightning holes in the structure also add considerable stiffness. i see the staged failure as a good thing, it means the failure at one point hasnt led to total failure as the next point gets overloaded. it looks like the impact/ folding failure has stopped at each rib/spar join and not become a sudden catastrophic failure of the whole wing. only the ever increasing weight during the ground impact has caused the wing to fail progressively at each rib point, and not suddenly at the wing root of lift strut locations.
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