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Elite Joined: Aug 19, 2004 Posts: 1089

Hey Aggie,

Forget I said anything. My only point is that the perfect lines drawn on the F-22 and F-35 won't necessarily be that way in reality which could result in significantly different... umm... predictions? And yes... wind tunnels are great. Better than CFD. But CFD is surely better than 2D pencil and paper compressible flow analysis. I guess that was a second point.

As for my qualifications (if you want to call them that)... I took several grad courses in aerodynamics/CFD/viscous flow in the process of getting my undergrad aero degree. I know enough to know when I'm dealing with a real authority and when I'm dealing with a charlatan. (I am not referring to you... don't get the wrong idea.) Anyway... one should probably have a Ph.D. (or equivalent experience) to lecture on these topics. I'm not lecturing on any of them, but this entire thread is definitely in lecture format.

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Elite Joined: Aug 19, 2004 Posts: 1089

SnakeHandler wrote:

Find better money, huh? Don't blame you. What do you do?

Why are you asking me personal questions on a public internet forum? You assumed incorrectly about my occupation, so I simply corrected you. That was not an invitation for you to make more (possibly incorrect) assumptions or ask more personal questions. Sorry if this sounds rude, but I don't know you except for the fact that you've said some nasty things to me on here in the past.

Veteran Joined: Jul 01, 2007 Posts: 336

Just curious, that's all. Everyone else is drunk and passed out here after the game and I just got bored. Besides, it might make things easier for you if people know where you're coming from. No hard feelings about the past. Yanking people's chains is something guys in my line of work do for fun. There was no malice behind it. Just trying to make people's skins a little thicker.

Raptor_One wrote:

Hey Aggie,

Forget I said anything. My only point is that the perfect lines drawn on the F-22 and F-35 won't necessarily be that way in reality which could result in significantly different... umm... predictions? And yes... wind tunnels are great. Better than CFD. But CFD is surely better than 2D pencil and paper compressible flow analysis. I guess that was a second point.

As for my qualifications (if you want to call them that)... I took several grad courses in aerodynamics/CFD/viscous flow in the process of getting my undergrad aero degree. I know enough to know when I'm dealing with a real authority and when I'm dealing with a charlatan. (I am not referring to you... don't get the wrong idea.) Anyway... one should probably have a Ph.D. (or equivalent experience) to lecture on these topics. I'm not lecturing on any of them, but this entire thread is definitely in lecture format.

No hard feelings. I was also taught a good engineer questions everything.

Veteran Joined: Mar 10, 2006 Posts: 343 Status: Offline

yeah, I only took a basic compressible aerodynamics class getting my BSAE and a few runs using supersonic tunnels so I wont try to say I know all this stuff.

Raptor One, you took grad level classes getting your undergrad? Rough stuff man, congrats!

Veteran Joined: Mar 24, 2007 Posts: 379 Status: Offline

Little secret - grad school is much easier than undergrad - more individual time with profs, more time to study what YOU are interested in, not the standard curriculum. That's my experience anyway.

johnwill wrote:

Little secret - grad school is much easier than undergrad - more individual time with profs, more time to study what YOU are interested in, not the standard curriculum. That's my experience anyway.

Ive got several friends still at college saying the same thing.

Veteran Joined: Mar 10, 2006 Posts: 343 Status: Offline

oh man, I cant wait to start Grad School now!! I was excited before but that sounds awsome! I was fortunate enough during my undergrad to become friends with one of my proffessors so we would sit in his office and talk about aerodynamics and performance for hours.

Elite Joined: Aug 19, 2004 Posts: 1089

sprstdlyscottsmn wrote:

yeah, I only took a basic compressible aerodynamics class getting my BSAE and a few runs using supersonic tunnels so I wont try to say I know all this stuff.

Raptor One, you took grad level classes getting your undergrad? Rough stuff man, congrats!

As others have already indicated, graduate courses (in your favorite subject at least) are generally easier than undergrad courses. The concepts are not necessarily more difficult to wrap your head around, but they can be. You may simply have to spend [much] more time in your professor's office during office hours. Sometimes undergrads just frequent the professor's office hours in hopes of getting an edge over other students in one way or another (not implying anything improper). When it comes to grad courses, you sometimes have no choice but to go to office hours. There'll be some homework problem that you simply can't figure out on your own no matter how well you've read/understood the textbook(s), lectures, etc. The professor will try to help you out as much as he can without giving you the answer on a silver platter.

Veteran Joined: Mar 24, 2007 Posts: 379 Status: Offline

As I said earlier, grad school is easier, but it will demand more of your time, especially when you start on research projects, writing papers, a thesis, and prep for oral exams. It was easily the most enjoyable time of my college days.

Elite Joined: Aug 02, 2006 Posts: 942 Status: Offline

Jeez...

OK, let me put it this way.

(1) An aircraft's choice of plan form does have an effect its performance at supersonic speeds. That is undeniable.

(2) The earlier discussion merely illustrates the Mach angle associated with the leading edge sweep and nose-to-tip angle of the aircrafts discussed. The Mach numbers associated with these angles can indeed be calculated to the precision used.

(3) By no means is anyone saying that these exact Mach numbers define the speed limit or efficient cruise limit of the pertinent aircrafts. Nor is anyone saying that the angles are the definitive or even the predominant indicator of these aircraft's aerodynamic efficiency or the lack thereof.

Veteran Joined: Mar 11, 2008 Posts: 349 Status: Offline

Just curious how an F-35 would perform with canards and 2-D vectoring? Maybe the whole B version should have been more oriented towards a purely STOL, employing vectoring/canard, and yielded on the lift fan? Just some thoughts. TIA.

One thing that has not been highly publicized about the F-35 is that it was designed with canards! It was during the six hundred hours of wind tunnel testing at NASA Aims facility in Sunnyvale, Ca. that the canards were removed.

Adrian

Hi avon 1944,

F-35 with Canards? Do you have some pictures/links on this?
Sounds very interesting!

Thanks
Max

Veteran Joined: Mar 11, 2008 Posts: 349 Status: Offline

avon1944 wrote:

One thing that has not been highly publicized about the F-35 is that it was designed with canards! It was during the six hundred hours of wind tunnel testing at NASA Aims facility in Sunnyvale, Ca. that the canards were removed.

Adrian

Interesting, thanks for info. I just think if a 2-D vectoring canard fitted STOL version was marketed, instead of the lifting-fan STOVL, they might have chopped $5-10 billion off R&D, been better on sched, not have had to compromise on internal bay and not to mention, had a better air-air platform? I know.. hindsight.

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Forum: F-35 Lightning II

Canard vs Tail