10/28: Next generation fighter

[Undertoad]

Yesterday they announced that the jet on the right, the Lockheed Martin version, will be the one produced to be our next strike fighter (and also Britain's).

The loser was Boeing's plane on the left there. I guess they didn't want the plane to be smiling as it launches.

[Hubris Boy]

Yes. They also announced that Raytheon was awarded the contract to produce the next generation of "smart bomb" that will be used with the new platform. Here's a picture of it:

[Chewbaccus]

Just goes to show: Our officials are agressive, but not sadistic.

~Mike

[Chewbaccus]

My first post was in reply to Tony, but Hubris, that's the funniest goddamn thing I've ever seen. Thank you.

~Mike

[smed]

That is fhe funniest god-damn thing I've seen in a long time!

Wonder how the newest smart bomb technology holds up when the fighter delivery agent reaches Mach II ??

Holy shit that is funny though.....

[scampo]

lol, i wish they shot out criminals with hatred of afghanistan armed with rocket launchers and m16s. on the way down they could just shoot the shit out of anyone.

[juju]

I think it was Whit that told me about this next-generation fighter-jet. (I could be wrong though..i don't remember). It's a prototype for a plane that's still in development.


[from the article:]

<b>
The Boeing Company and the National Aeronautics and Space Administration (NASA) are teamed to develop a prototype fighter aircraft designed for stealth and agility. The result--after only 28 months--is a subscale tailless aircraft called the X-36.

The 28-percent scale, remotely piloted X-36 has no vertical or horizontal tails, yet it is expected to be more maneuverable and agile than today's fighters. In addition, the tailless design reduces the weight, drag and radar cross section typically associated with traditional fighter aircraft.
</b>
...
<b>
Using a video camera in the nose of the vehicle, a pilot controls the flight of the X-36 from a virtual cockpit--complete with head-up display (HUD)--in a ground-based station. This pilot-in-the-loop approach eliminates the need for expensive and complex autonomous flight control systems.
</b>

Cool, huh?

[Chewbaccus]

How would it manuver? Air jets?

~Mike

[TheDollyLlama]

This thing is so damn light. i just wonder what could be powering it to keep it under that weight. I'm guessing the structural parts are some lightweight fiber or polymer, but the engine...hmm.

I'm also wondering how a plane without vertical stabilizers could yaw.

[TheDollyLlama]

Course, not knowing much about the real details of the plane, I'm going to judge on looks. Fortunately, our future air warriors will not be flying fighters that look like guppies.

Tragically, by this same standard, the USAF really missed the boat on the F-23. See link:

http://www.fas.org/man/dod-101/sys/ac/f-23.htm

[MaggieL]

Originally posted by TheDollyLlama

I'm also wondering how a plane without vertical stabilizers could yaw. [/b]

Actually, most aileron designs *cause* "adverse yaw". Good designs minimize it, but one of the main functions of the rudder (not the vert stab, whose job is adding yaw *stability*) is to *cancel* adverse yaw. Rudder is to vertical stabilizer as aileron is to wing, and elevator is to horizontal stab, in conventional empennage (tail).

This puppy, being fly-by-wire, *computes* what has to be done control-surface-wise to accomplish any particular attitude change.
In the photo you can see that one control surface on the port wing is lifted a bunch, and the corresponding one on the starboard side is up too, but by what looks like not as much. The flight control system is using them asymetrically. On a conventional aircraft one aileron goes up, the other must go down and you get a roll force, along with some unintended yaw because the down aileron makes more drag than the up aileron does

This thing can nose up/down by using the surfces together, roll by using them against each other, and yaw by adjusting the differential. And if the top and bottom surfacses are independant (looks like they are), they can eve be used as speed brakes.

Sweet.

Also apparently some "air jet" like stuff is being done:
"The tailless design of the X-36 greatly enhances the stealth characteristics of the airplane and promises to provide greater agility than current fighter aircraft have. The design also reduces weight and drag and explores new flight control technologies, such as split ailerons and thrust vectoring."

[TheDollyLlama]

wow. now that's a reply. maybe you can answer this one for me.

You're saying that this thing would yaw by vectoring the thrust, right? how is that different than the angle of attack maneuvers the f22 is capable of? Does the f22 achieve high angle of attack by opposing the thrust vectoring with the ailerons? I know we're talking about two different motions, yaw and pitch, but with the same force, right?

[Araneas]

Too bad the one on the left looks like an updated Corsair 2 (A-7). I loved the look of that plane.

[MaggieL]

Originally posted by TheDollyLlama
wow. now that's a reply. maybe you can answer this one for me.

You're saying that this thing would yaw by vectoring the thrust, right?

Not quite, although apparently it's capable of that to some extent, too. But by deploying the control surfaces differentially (and especially note that they're not coplanar) the resultant forces can go in all kinds of different directions. It's vaguely analogous to turning a tracked vehicle like a tank or a bulldozer by moving the tracks at different rates. The key to the trick is that a computer is constantly translating the pilot's command inputs into movements of the control surfaces by calculating what forces will be devloped and how the forces will affect the aircraft's position and momentum (or "state vector"). No mechanical control linkage could ever do that.

how is that different than the angle of attack maneuvers the f22 is capable of?

Actually, getting to high-alpha (angle of attack) isn't all that difficult; every student pilot is taught how to stall the airplane...with emphasis on how not to except when landing. What makes flight on that edge tricky is maneuvering at all once you get there.
As alpha exceeds a critical value that's a function of airspeed, the laminar flow across the wings and control surfaces separates and becomes turbulent, lift is lost, and the surfaces "stall". A stalled control surface or wing doesnt exert any significant useful force on the aircraft, so whatever manuverability you have at that point is going to have to come from somewhere else--namely a reaction force like vectored thrust. That's how a Harrier takes off and manuevers in hover, and how the Shuttle is turned while it's on-orbit.

A hovering Harrier could be said to be in a high-alpha flight regime because its effective airspeed is near zero, so critical alpha is vanishingly small; the aircraft is competely stalled but is still manuverable because of vectored thrust. It's no longer a genuinely aerodynamic creature; it's basically ballistic.

[TheDollyLlama]

it seems to my lay mind that the differential approach you're talking about would result in greater drag, as well as being more complicated with greater chance of failure, than a vertical stabilizer/rudder approach. Maybe not appreciably, especially if you can do without a large projection such as vert stabilizer(s).

you use such big words...brain hurt..

so are you an aero eng, or is this ground school stuff?