Bob Llewellyn

A difficult one. I agree that inappropriate discrimination, particularly in the form of unconscious racism, is a problem in Australia. But nationality is not race, or in this case race-linked; and whilst the irish have been the butt of many jokes - so specifying Alan J as irish carries faint derogatory overtones - it is still a fairly accurate description. I have Welsh, English, Scottish, and - alledgedly - Irish ancestors; also Spanish, if my maternal grandfather is to be believed. I have no problems being associated with the country that gave the world Terence "Spike" Milligan...

GG, no offense, but you are a particularly cranky type of antelope... I do not care whether Alan Joyce is a fig or not; I think Marty_d's description simply identified him

Anyone know the "clean" stall speed?

But those kiwis are cunning, unlike professional management...

"I won't work for you if you fire me!"... sounds an effective bargaining position ... but Tony Abs said he understands the strategic importance of Quantas... if it's bloody strategic, why is he doing nothing? Surely he could steal... er, "nationalise" it, and replace the board with the P.U.P. or someone...

"Management...savvy"... no, sorry, I don't understand that phrase. If they had savvy beyond their own career earnings, why would they have management qualifications? I note that I have met people in management roles with savvy, but not with any management qualifications beyond experience. Three of them, from memory...

We had a roof. When I venture a technical opinion, I expect to either be able to substantiate it, or willing to withdraw it. So far Mr Acro has given three cases of "you're wrong because I disagree with you", without substantiation. It is his right to disagree with me; but if it's only an opinion (it keeps changeing, except for my wrongness?), why doesn't he have the grace to say so? If it's sustainable, why does he reject all of my references, and supply a selective generalised quote? I have no objection to him having an unsustainable opinion which differs from my understanding of the facts, such as they are; I do object to him claiming a superiority of opinion based upon nothing. I can piss right over the toilet these days...

"...and that the boundary layer is a region of rotational flow so that the stagnation pressure is not constant everywhere..." from the same page. So you use selective quotes instead of understanding the subject? Which boundary Layer Theory, by the way? You said "Static pressure outside the boundary layer is the same, typically, as on the surface." Now you are saying that static pressure inside the boundary layer is constant, by selective editing. Which definition are you sticking by? They can't both be right... Please don't feel that you need to reply; your insistence that your criticisms MUST be correct, even if you have to contradict yourself to prove them, demonstrates that this debate is, essentially, futile.

Get a Thruster - they don't leak, they embrace the rain!

Continuity is the property of continuum mechanics, as used by Newton in the theorem that the transverse viscosity is proportional to the strain rate. Conservation of mass per se is not a principle of physics; conservation of momentum, and conservation of energy, are. An implication of continuum mechanics is the constant mass flow of an incompressible fluid through a tube of varying cross-section; but I assumed we were talking about air, a compressible fluid, in a free state - the atmosphere - rather than within a garden hose. Clearly we are talking at cross-purposes.

The boundary layer is the region in which the continuity, as expressed by Bernoulli's total energy equation, no longer holds due to viscous transfer into the skin. Look up a textbook yourself, buddy. Now, if an icthyoid body of fineness ratio 5 did not have a boundary layer, the pressure recovery - suction back to the point of maximum cross-section, increasing pressure thereafter - would give no net drag. At the outer edge of the boundary layer - by definition - the local static pressure is changed by total energy effects, and the local static pressure is not the free atmospheric true value. At the inner edge of the boundary layer - the laminar sub-layer, look it up - the local static is indeed very close to the true static. At the outer edge, it is totally at the mercy of the free stream velocity depressing the local static to compensate for the dynamic pressure, which is an expression of conservation of energy, or more accurately - wait for it - CONSERVATION OF MOMENTUM! look it all up. Hoerner, "Fluid Dynamic Lift"; "Fluid Dynamic Drag: Theodore Theodsen, "Thin Airfoil Theory"; Lanchester, "Aerodynamics"; any university course on Thermofluids

didn't lose 200ft on final didja? a decade back Bill Dinsmore asked me to stall an SB Drifter; by dancing onthe rudder pedals, i was able to keep the separation bubble centred until it was indicating about 24kts - Bill said "bloody glider pilots - MY AEROPLANE", unstalled it, and told me to do it again but keep my feet still. There are very few aeroplanes in which one can keep the separation bubble centred to below the certification stall speed; and it's pointless as an exercise down low, as any separation bubble increases the rate of sink substantially. If you look at the drag curves (NACA data) in Abbot & v. Doenhoff, or anywhere else, you will see that the airfoil L/D falls off hugely a couple of degrees before the lift curve slope becomes zero. The wing drop nibble you should be feeling - and quite reasonably picking up with rudder - is in the pre-stall, high drag part of the airfoil map. You should be fast enough on final not to get a bloody wing drop. I agree that once you know your way around a particular aeroplane's flight characteristics, you can fly close to or even partially stalled - this does not make it a low-risk occupation, or even a good habit in circuit (flying too slowly, I mean!). From memory, pilot fatality rates vs experience peaks at about 100 hrs, then again at 400 or so? Is not eroding the safety margin of "minimum safe airspeed" an advanced pilotting technique?

if the air is not moving past the surface, I agree. If it is, the continuity equations disagree. I'm with continuity of momentum, because elsewise the wing doesn't work.

yep, if an LSA to ASTM 2245 drops a wing more than 60 degrees during a straight stall (despite corrective inputs), it's a fail...

I think a semantic difference here... in a sailplane, one can have the inner wing start to drop in a turn (thermalling, generally); and the rudder has the authority to reverse the yaw rate - normally only momentarily, don't want to lose that thermal! - which doesn't just stop the wing going down, it comes back up (all whilst holding back stick for the turn). I doubt very much Dafydd is advocating ignoring the rudder; but you yourself said, "use the rudder to stop yaw". I think Dafydd is saying, in non-sailplanes, don't fool around with the feet and ignore the stick when a wing tries to drop.

boundary layer - the boundary layer is normally a few inches thick by the tail, even with the slipstream buzzing away...

The rat's gonna get me, I'm sure... anyway try "acceptance of personal responsibility" (for one's own safety), and "threshold of sensory overload" - for me, being part of the travelling experience on the 'bike is very similar to flight. I admit, I find Thrusters, Drifters, and sailplanes much more bike-like than the Lightwing GR-912 I flew...

As several (thousand) people have found, there are cheaper ways than buying politicians... I feel we should strive to avoid that path...

"total pressure"?

Hmmm, don't agree on the public service - we need free filing of Applications under the Adminstrative Decisions Judicial Review Act 1988, then the PS can run the country and we can step on their necks any time they abuse their discretionary authority. Once that's done, mince the pollies, accountants, those with degrees in Management:yelrotflmao:, and lawers. The RAAus board needs to learn about the ADJRA, too...

Roosevelt's New Deal has a lot to answer for, especially in the field of short-term greed over enlightened self interest - my grandfather worked for Holden; in the late '50s (I think), he was tasked with reblending the paint on the doors so it faded within 24 months and started to flake off within 36... he left in disgust. Shakespear had too narrow a vision; we need to croak accountants as well...

...but the power setting changes it... hmmm, a challenge...

ok, Dafydd reminded me of a blindingly obvious point - the pressure field under the wing is caused at the expense of the local dynamic pressure, so the pitot reading IS lowered in that location. Trying again: EITHER a combined pitot/static head should be nearly a full chord ahead of the wing, OR you need to get a pressure map for the airfoil (or grope around in the air until you find a location that works), and put it in the unaffected zone; OR(2) you need to stick it close under the wing - a la Piper - and tweak it - a la Piper - until it works. 4412 / Clark Y both have a pressure-passive zone, and about 0.15 chords fwd and 0.15 chords down (if more than ~40% outboard - or lower if inboard of 40%) should work through the positive AoA range; 0.2C fwd and 0.2C down should work anywhere along the wing, out of slipstream... since any mods to the system normally require you to do a calibration with a pivotting pitot / trailing static, most people just do an accurate calibration on their existing system, and call it quits.

'cause the Thruster donk is up high, the slipstream corkscrews through the crew compartment... blows the string across too...

Water acts as a pro-crazing structural lubricant for acrylics (perspex etc)... I've used Rainex on two (2) perspex windscreens, about 3 years between them, about 60,000km on Queensland country roads, they survived because the rainex meant I only had to use the wipers about 3 times. I use it on all my Thrusters, all my motorcycle helmets, glass windscreens, and the dog. None have yet crazed in use, although a visor got a nasty scratch after I rear-ended a semi trailer on a 'bike... Look, Jabs are so slow, sometimes the rain catches up... get a Thruster...