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Toryu

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About Toryu

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    Aachen
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    Cloudsurfing

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  1. The subsonic conversion should be robust and good to go.
  2. Depends on the formula(e) it uses. Most probably no. Keep in mind that the whole ICE-T stuff is just fudging a pressure-measurement into a somewhat useable airspeed guesstimate. It's severely limited, but so far it's the best shot we have. Also, several steps in the ICE-T conversion-process are actually useful (CAS and EAS) for load-calculations as that's basicly what the aircraft "feels" in terms of pressure-distribution. So it's not totally worthless... CAS to EAS involves a ram recovery factor to account for compressibility and EAS to TAS takes air temperature into account. You can squeeze that into a relatively simple formula. When you're going supersonic, though, there's not only the stagation/ ram rise at the entry of your pitot tube, there's also a shock-wave in front of it with a pressure-differential (density-, temperature-differential) accross the shock. In subsonic flow you're measuring total pressure versus static pressure and then figure out a Mach number by taking a fancy formula and entering those two values and the ratio of specific heats (which is 1.4 for anything slower than hypersonic). That Mach number can easily be converted to TAS by knowing OAT. In supersonic flow, that measurement is spoiled by the normal shock-wave in front of the pitot tube, which causes a total-pressure loss and hence inconveniently falsifies your measurement even more. Also, it's hard to solve analytically and you'll need tables to find an answer. Check the Raleigh pitot tube formula and you'll see what I mean. You could figure out the Mach behind the shock (normal shocks always compress to subsonic => use the subsonic formula). Then you can figure out the Mach before the shock via a table/ formula. In any case, the way of determining TAS would then be similar to "subsonic": You'll solve for Mach and then you'd try to go via OAT (which is harder to do than subsonic, as "OAT" is measured behind the shock, which of course gives us a false reading - thanks to another shock table and the Mach-number before the shock which we just figured out, we can figure out the temperature ahead of the shock, though) and work out your TAS.
  3. Sure. I'll do it in SI units, though. 1) We know that lift equals weight. Weight is mass times earth's gravitational acceleration. L = W = m*g 2) We know that L = 0.5*rho*v^2 * CL * S ==>> CL = L / (0.5*rho*v^2*S) m = your mass in [kg] g = earth's average gravitational acceleration, which is 9.81m/s^2 rho = air's density, which under ISA-conditions is approximately 1.225kg/m^3 v = airspeed in [m/s] CL = what we're looking for, dimensionless S = your reference wing-area in [m^2]
  4. Yes. Just figure out your CLmax for each airspeed (it varies with Mach, but assume it to be constant for a first approximation) and apply it to your Excel table.
  5. Short answer: Yes. If your weight goes up, your required lift goes up. That means (all else being equal) you'll have to go faster to achieve the same amount of lift/weight relationship. Determining "g" is nothing but dividing your lift available by your current weight. If "lift = weight", we'll get 1g and so on. "G available" is your lift available (F_L = q*cl*S) divided by your current weight (F_W = m*g). That only works that easily "right side up" (for any other case, you'll have to figure out the components of your lift and weight verctors according to your cartesian system first), but it's a good starter for understanding what "g" actually is. It's nothing but an acceleration based on unequal forces (lift and weight, thrust and drag) acting on your airplane. "9g" means that the wings are providing enough lift to carry 9 times your current weight, or that your airplane accelerates at nine times the earth's free-fall acceleration (hence the term "g") into the lift-direction. All is relative _______ q = 0.5*air-density*v^2 cl = max available lift-coefficient at current Mach S = effective wing-area
  6. A very nice scenario, dtmd! I never cared for the "desert pink"-sheme, but it doesn't look too bad on the Skyhawk at all. FWIW: The book is highly recommeded - it also features a rather interesting cockpit-picture of a TA-4K going straight down and supersonic...
  7. AvWeb Short Final

    Couldn't think of a shittyer, yet more beautiful place to fly than Alaska. As I said before: The CG fellas get way too little credit for their job. Juneau is a very cool airport - basicly between a rock and a hard place (mountains in 3 directions, a hill in the fourth direction). The only IAP-procedures (LDA or RNAV) are offset a couple of degrees and the circling-approaches have you maneuvering in a tight valley - especially if you're in a jet. The ODP is also *interesting* (not so much for a helicopter, though).
  8. Prayers for the families and victims

    No, it's a reference to the bill that is supposed to legalize owenership of silencers (beyond the current boundaries), so that people can buy more useless stuff for their guns so they can be tacticool. In other words: A noontime parkinglot handjob to the gun-lobby.
  9. Saw the film. It was pretty entertaining.
  10. Prayers for the families and victims

    Posting sympathies in internet-forums doesn't do anything good unless a member is affected. Prayers don't achieve anything either. Better gun laws do. Sems like about 80% of the american populace want stricter gun-laws based on common sense, as opposed to giveaways to the gun-lobby. Silencers - seriously? Politicians "praying" and talking of "better times for that kind of discussion" (when exactly would that be ?) are insincere, morally wrong and weak. "If only we could do something". Yeah, if only you could.
  11. A bit more on flying the Sea Vixen can be read here: http://vintageaviationecho.com/flying-the-sea-vixen/
  12. F-35 by the numbers

    The whole North is pretty full of large birds that will ruin your day if you take a ride through a flock. Geese are pretty fat and dumb (and who knows - happy?) and won't yield to a fighter coming along at 450kts. Now, take one down your intake and your engine is a goner*. Split the intakes, have them feed an engine each and put them on each side of the fuselage and you'll have a much better chance of coming home - if we're talking a low number of birds anyway. Ask Sully how he feels about a flock of geese (or that E-3 crew out of Elmendorf ). Eagles aren't that bright either, btw. Now, the F-35 has a higher bypass-ratio than other fighter engines, to get that mass-flow up. Therefore, chances of survival are slightly higher, as the chance of the bird missing the engine core are slightly higher (a tiny bit more bypass-air area compared to the core-air area on that fan-stage) - but still: Take a goose down the intake and you'd better strap on those walking-boots really quick. Pure and good old-fashioned engine-failures are very much a thing of the past, thanks to extensive on condition monitoring and preventive MX. Actual engine-failures nowadays are more down to a production- or QM-related issue than to a random component failure. * We're talking low bypass turbofans - that bird WILL go down your core and duck up your LPC and hot-section.
  13. Got your point, but it wasn't really an upgrade - more of a replacement. Performance-wise, they should have invested in the Avon-version, though. Mirages generally seem to take engine "upgrades" rather well: The MIII got to be insane on Avon-steroids. The F1 really got going with an M53 and very much later with an RD-33.
  14. Speaking of the "straight up at 60kts" episode: One of the coolest features of the M2k has to be it's relatively crappy engine. The M53 is a single-spool turbofan (!) with a very modest pressure-ratio accross the compressor, which incidentally makes it almost stall-proof. Also, it should make the engine very responsive, especially in the later production-lots which are FADEC controlled. Ed Rasimus once wrote a story of him flying a simulated attack mission against Madrid in his Torrejon-based F-4C. He was intercepted by a spanisch Mirage IIIEE and the little Mirage was all over him at high altitude, despite the (also) relatively crappy Atar 9C engine. Simplicity is a weapon at times.
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