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I'm not familiar with the Concorde 'stretch' but I presume it had the same cause as with the SR-71...heat expansion.
The SR-71 had several design features to accomodate this problem. One was the longitudal corrugations of the wing surfaces. The hi-flash-point fuel (JP-7?) was also used as a heat sink. The a/c also leaked fuel while on the ground due to the designed loose fit of some of the structure.
JL
I'm not familiar with the Concorde 'stretch' but I presume it had the same cause as with the SR-71...heat expansion.
The SR-71 had several design features to accomodate this problem. One was the longitudal corrugations of the wing surfaces. The hi-flash-point fuel (JP-7?) was also used as a heat sink. The a/c also leaked fuel while on the ground due to the designed loose fit of some of the structure.
JL
Christ
Bill when will you sieze with the pissing matches?? Don't you think I know what this is all about ?? Could you answer every single of those questions above Bill ?? No. Also when did I ever become an a/c designer Bill ? Have I ever claimed to be one ?? All you want is a fight, you have no intentions of keeping this cordial.
I intend to keep it cordial
Specify the quaestion you want an answer to - but first demonstrate that you can answer the questions - even if it is "this is the approach, theses are the complications, and this is why, or why not, atha approach can be relied upon?
If you know anything about the subject you can put at least the APPROACH out in front of us - I don't expect detail knowledge from a practitioner but I do expect one from someone knowledgable about the topic
It's also very convenient that you avoided all other of my questions, and the reason is clear: You can't support your claims, your bold claims that the P-51 109 are close in terms of turn performance and that the field of aeroelasticity was considered witchcraft by aerodynamicists during WW2 being perfect examples.
You and I have debated this forever, I have matched your 'related anecdotal comments' with many encounter reports, we have cussed and discussed the RAE reports to death, I have cited Rall's comments about the Mustang versus the 109 when he was running the training program for Luftwaffe leaders - you rejected his comments as 'flawed' because he was afraid to push it to its limit, I have asked for the flight test results from Rechlin that you say disprove the tests at RAE in March 1944.. but you don't have those...
I say 'turn with' you say 'hopelessly inferior' - combat results early and late are heavily skewed to the Mustang. Pilot quality is essential and a known variable.
You dive deep in aero to prove your thesis based on wing CL, I show you aero is more complicated than that - when you get confused you solicit Gene.. So - that is where we are after six months. Please step out and ask one person to substantiate what you can't - namely that the Me 109 clearly outperforms the Mustang in three different flight altitudes at three different speeds to compare stalling, aileron control, turn radius for each and the representative G's in the turn.
So far ONE test has been dissected, but in that test the Mustang III was described as 'clearly superior' - show another report by Luftwaffe professionals discounting this in controlled conditions and we'll talk - end of talk on this subject until you do?
Now I can tell you what aeroelasticity is and what its effects are on an a/c (Although wiki covers allot of it), I can also tell you that it was in no way witchcraft during WW2 which you claimed it was and that even the Soviets had Scientists specializing in this field, namely M.V. Keldysh, in the early 1930's.
Bring to the table ONE example of an analytical approach to modelling an airframe mathmatically and we can accept it as you thesis that it wasn't an art in WWII. By the way 'art versus science' is the phrase. 'Witchcraft' is your way of misquoting what I say.
That having been said we get better at each field within science as time goes by, and ofcourse aeroelasticity is better understood today, and also A LOT easier to guard against because of the ability construct and test an airframe in sophisticated computer simulations before ever deciding to actually build it.
Duh. Which is precisely the point I have been leading you too.. ditto aero simulation for the same reasons. Ditto why P-38 Flutter was discovered after crashes, not during design, or Me 109 horizontal stabilizers (according to Nowarra's research) failed on the early 109F's because they didn't correctly model the cantilever tail or its natural frequency, and the Comet kept putting metal and bone in the ground - for similar reasons - but leading to fatigue versus resonance/departure.
During WW2 the methods were crude by comparison and the most reliable results were achieved by conducting test flights. One method used was carefully examining the wing profile under heavy loads while at the same time establishing the maximum load factor of the wing itself.
That is NOT what you said to start this debate - and does NOT represent the theory of Aeroelasticity - only test to failure.
Vibration and thermal stress testing to failure under repeating loads is not all that old - maybe late 1960's
Finally I asked you to wait until Crumpp came on the scene, why did you ignore this Bill??
Primarily, because I respect Gene's knowledge about these subjects but not yours. If Gene wishes to correct me, we'll make sure he has my thinking right versus his own and we CAN debate civilly, out of mutual respect.
Anyway following your next reply I'll consider wether it is at all worth participating in this thread..
All in all I consider myself friendly not to just ignore this thread..
So far ONE test has been dissected, but in that test the Mustang III was described as 'clearly superior' - show another report by Luftwaffe professionals discounting this in controlled conditions and we'll talk - end of talk on this subject until you do?
You and I have debated this forever, I have matched your 'related anecdotal comments' with many encounter reports, we have cussed and discussed the RAE reports to death, I have cited Rall's comments about the Mustang versus the 109 when he was running the training program for Luftwaffe leaders - you rejected his comments as 'flawed' because he was afraid to push it to its limit, I have asked for the flight test results from Rechlin that you say disprove the tests at RAE in March 1944.. but you don't have those...
I intend to keep it cordial
Soren, here is a fundamental problem. You do not know much about either fundamenta Aerodynamics (the underlying physics of fluid mechanics) or airframe structures and the disciplines of modelling an airframe along different approaches depending on which problems you are trying to solve.
If you would stick to what you know a lot about, we wouldn't get into these 'pissing contests'
Virtually every equation you have used, including CLmax, are mathmatical approximations based on different boundary conditions and the model you are trying to solve.
The classic airfoils in the tables are always 2D, 'infinite' wing, constant cross section and no twist. Then get ready to modify the crap out of it based on twist, based on tip/chord ratios, based on tip geometry, based on wing plan from, based on 'cleanness' of surface (nacelles, bomb racks, dirt, wavy surfaces)..
But you swoop in on someone who may know less than you about boundary conditions and start pontificating.
Fine - sit out. I can debate and I can learn - what have you got to teach me?
No offence, but assuming it's a personal attack seems a bit paranoid.