Aerodynamics thread
- Thread starter siegecrossbow
- Start date
It only seems un-helpful because of that liberal mindset, airflow is linear, and very predictable. It does follow the wing, even though the velocity over the top is greater, (as it has been designed to be), at the trailing edge it all comes together again, just as water flowing in a stream is disrupted by a rock. There is an eddy or swirl as that happens, if you place a LERX or Canard forward of the main wing?? that will affect airflow over the wing, if you place the control surfaces behind the main wing?? that will not affect flow over the main wing??
Cooks choice? eh?? we are like the blind men describing the elephant, I prefer to put my tail on the rear, you Euro boys like to put the tail in front like Wilbur and Orville?? LOL there is more than one way to skin a cat, but, the simpler the better, the F-22 is a very simple airplane compared to the J-20, also more efficient IMHO, but isn't that what makes the world go round?
I would love to see the blue smoke??? but then I just like Blue, but I am building an NOS Pinarello Prince SL, and it is blue, I am building it as a Flat Bar Roadie, because I want to. Different, but simple, down tube shifters, brake levers on the handlebars??? Shimano 9 speed groupo??
Well, aerodynamics isn't so very simple. In normal horizontal flight the main wing induces an upward component in the airflow at the place of canard surfaces and a downward component at the place of an aft tail surface and at the same time a canard surface induces a downward flow on the main wing and the aft tail does the same because its lift is generally pointed down. Stability and control engineering needs it consider these things very carefully. Think also of the influence of deploying high lift devices in this respect.
The engines with trust vectoring are far from being more simple than what the Europeans did with their canard designs.
The corollary of simpler the better is no one invites complexity unless they have to. Americans can go for simple designs because they have engines that are ahead of everyone else. However, if a design is so stressed that a superior engine no longer compensates, then either you have to go for unorthodox aerodynamics or have something like F-35.
Actually aerodynamics are very simple when you lose the math that makes it complicated, I am a pilot, I understand very well that air is a fluid medium, with flow properties that may be replicated with water. I spent LOTS of time playing in mudholes, creeks, ponds, pools??? with the water hose. I have also spent a lot of time playing with airplanes, prolly starting around 2 years old, yes I still have diecast airplanes, a couple of Cox Corsairs, a couple Spitfires, and spares, and an electric cheap helo, in addition to several hundreds hours of general aviation experience, 5 to 30 minutes at a time normally. I still fly a Cessna 150 with around 100 horsepower, it all depends on aerodynamics, and having a grasp of the tool and the medium??? Low powered aircraft demand that you have a generous knowledge of what you need to do, in order to get said aircraft to do what it has to do??
I have a relatively sophisticated flight simulator on my PC, I have looped and rolled the F-18, J-3, C-130, Boeing 737, and 747, Extra 300 and the YF-23?? The F-18 is a very easy airplane to fly, and wants to please? the B-737 does a very nice aileron roll, and the 747 is passable??
My point is that airflow is very predictable and linear, I have stated that I can "see" lift, by that I mean that it isn't too difficult to visualize the forces at work on an aircraft in a given configuration, at a given airspeed. I recall very clearly the several videos of inflight separtions of wings/control surfaces and the subsequent break-up of aircraft, some like they had hit a brick wall, no I have no delusions that flying isn't extremely dangerous, nor do I undermine the abilities and intellect of aircraft engineers or pilots.
The F-35 is a very fine airplane as is the J-20, they are likely very similar in capabilities, although much different in configuration.
It is relatively easy to fly a modern airplane because the engineers spent thousands of hours making it so. If you read about the flying qualities of aircraft of eighty years ago when the designers woke up to the need to consider this seriously ...... It was mostly luck that made the DC-3 come out so well.
Regarding that aero package you already brought up in the J-20 thread, by now there's really not much more I can say about it.
Apparently those ILS covers beneath the canopy are now delta shaped with a 70° sweep. I've read somewhere their main purpose is to optimize airflow eventually reaching the vert stab. Those LERXs are for the main wing.
The Typhoon, from the beginning, was designed for superior kinematic / maneuver performance in the transsonic regime. And also efficiency when supersonic. That comes at a price in the slow speed / high AoA region. Something these things are ment to correct. So that it may break in the last area where F-18 / F-16 type aircraft may still hold a slight advantage.
Nevertheless, these high AoA maneuvers of course come at the expanse of drag. And the Typhoon, being an energy fighter, will likely alway choose a rate fight over a radius fight.
LOL, of course you don't, because that is NOT what the Brat said, I said that "AIR-FLOW" is linear, high lift devices disrupt that linear airflow momentarily to achieve the objective of creating MORE lift, slats or flaps increase the camber of the wing.
Engineers are not designing aircraft to be highly unstable in all possible situations, they are designing aircraft with "relaxed" stability in certain regimes in order to increase "agility", the ability of the pilot to quickly change direction, heading, energy levels, in order to gain a firing solution/escape vector.
Air-Flow is indeed "linear" as the aircraft is "moving through" the air in a generally forward direction, air does indeed flow from the front to the back of the aircraft, that's why the pitot tube is on the front of the aircraft, facing forward, not on the back facing aft??