Re: J-20 The New Generation Fighter Thread IV
thrust can be vectored, do you understand that?
it means its direction changes, thus you get shorter take offs, you can trim the flight, use it as a roll or pitch or yaw device
The F/A-22's nozzle, on the other hand, is the first vectoring nozzle. That means the pilot can move, or vector, the nozzle up and down by 20 degrees.The gases coming out of the vector nozzle help push the airplane's nose up or down. This vectoring increases the roll rate of the plane by 50 percent, making it much more maneuverable than other fighters.
he latter three surfaces are common to all airplanes:
The elevator controls the pitch (up-and-down movement) of the airplane.
The rudder controls the yaw -- the left-and-right motion along the vertical axis.
The ailerons control the rolling motion along the horizontal axis.
With the vector nozzle, the F/A-22 has a fourth type of control surface.
The F119 engines also give the F/A-22 a high thrust-to-weight ratio. That means the engines can actually handle many times the airplane's weight, allowing the plane to accelerate and maneuver very quickly.
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Today’s most maneuverable fighters use thrust vectoring, which can make a jet turn faster and more tightly.
Powered by Pratt & Whitney F119 turbofans, each with 35,000 pounds of thrust, the F-22A—the Air Force’s newest fighter—sports a nozzle that can direct exhaust thrust up or down as much as 24 degree
“Our [one-on-one] tactics have changed to incorporate the ‘post-stall’ regime, where other aircraft cannot operate,” explains Captain John “Rocks” Wagemann, who flies the F-22A in the First Fighter Wing at Langley Air Force Base in Virginia. Thrust vectoring enables the pilots to fly up and over in a very tight arc, Wagemann says, and “gives us the nose authority to turn the jet while the wings are stalled, similar to a controlled flat spin.”
NOBODY is saying TVC can't change thrust direction. In fact, that's the only bloody thing TVC is good for. So basically, that means the last four fifths of your reply is boring and irrelevant to this discussion. Actually, I would like to correct myself, four fifths of your post are boring and irrelevant to their discussions too.
Lift means how much force UPWARDS the wings are achieving by having low pressure air sucking the wing upwards from the high pressure air underneath, I fail to see how TVC assists the wing in that operation. If you mean TVC can assist in achieving lift by changing the AOA, then you might as well use tail planes.
And yes we understand thrust can be vectored, this is how rockets are manoeuvered in space. BUT, TVC doesn't increase lift per se, the engine thrust in conjunction with the wings do. Here's a scenario; an F-22 is flying straight and level, not at cl-max. If you "vector the thrust" (like you so enthusiastically implore us to) 20 degrees downwards, that will in turn push the plane's aft upwards and result in a negative AOA, also known as flying downwards; if you angle the thrust 20 degrees upwards, that will result in the plane flying at positive AOA, which, assuming the engines are powerful enough, will usually result in an increase of altitude. The latter scenario is one where the plane CAN increase its altitude using TVC, but that can also be done using tail planes.
So basically, my point is: what is YOUR point? If your point is that TVC can increase manoeuverability by letting the aircraft pull tighter turns, then by all means, we agree with you. However, if your argument is that TVC increases lift, then no we don't agree with you. TVC can change an aircraft's pitch to allow the wings to attain maximum lift coefficient, but so can a tail plant. If you have a TVC solely to help the wing attain max lift coefficient, then you're stupid for not making full use of your tail planes.
