Friday, July 21, 2006

New "Secret" Drone...

Defense Tech: High-Flying, Secret Drone Unveiled

So Lockheed Martin has an internally funded "high flying secret drone". It is mostly made from composites, with a thrust to weight of ~0.66. The payload fraction is ~11% of the GTOW. It is tailless, has "new" aerodynamics (new airfoil shape with laminar flow), and has all the automation needed. ~90ft wingspan. I haven't gotten the Aviation Weekly that talks about it yet, I'll add some stuff there.

From how it was introduced, and my estimations of the capability, the aircraft was not designed to be secret at all. The only secret in it was corporate secrecy. Lockheed martin needed to prove that they had the capability to manufacture and integrate large composite pieces like Boeing. They were using a low temperature process (only like 150 degress F vs 350 degrees F with an autoclave) that really hasn't been flight tested. The autonomous nature of the airplane would have been a secondary goal. It was weird that Lockheed did not have an airplane like the x-45A (Boeing) and x-47A (Northrop Grumman). Lockheed Martin did win both of the next generation fighter contracts. The autonomous features were proven in the Darkstar as early as 1996. The Darkstar was supposedly terminated in 1999, but rumors abound about its use in 2003 during the begining of the war in Iraq. The Polecat seems to be made to show off composites ability and that Lockheed has not lost the ability to rapidly (18 months) design and build unique aircraft.

One really neat thing about this airplane is that they have been hinting that it can fly over 60 kft, and will use contrail suppressing ideas. Jane's seems to think that you don't get contrails that high anyway so just flying high is enough. I don't know anything about contrails, other than how they are made. So, basically, it could fly high enough that you cant hear/see it, you can't detect it visually from the contrails, and it is low observable to radar. I wonder if you can see the temperature difference from the exhaust, using an IR sensor of some sort? It would have to be high res or have a really neat zoom, as an aircraft at that altitude wouldn't be much more than a few pixels with a commercial camera.

This picture shows the rear end of the aircraft, you can tell it is a development airplane because of the huge ass pitot tube sticking out of the front. The two engines each have their own exhaust, and it looks like the wing has some sort of sweep, starting about 4-5 engine nozzle diameters from the edges of the engine nozzles. There is some suggestion in the artifacts of jpeg compression that the engine nozzles are circular, and not half circles as you initially expect. The "shadow" in the right engine nozzle sort of "jumps" right at the edge of the nozzle.  You can see a control surface on the right wing. I am going to attempt to get estimates on trailing edge sweep and length of the control surface (the inner one, it probably has another one more outboard).

It supposedly has a 4 hour loiter, with the only fuel tank being in the center portion. Some thoughts have been floating around about putting fuel in the wings for more endurance. I am guessing that they were structurally designed to handle fuel loads in the wings.

Upon further analysis, I think that the back end of the aircraft is not straight as I originally thought. I really wish I had that software that I was using at Dryden for 2D images to 3D models. I could generate a top down view of the rear end of this aircraft right now, based on this one image. The front I am guessing is half of a circle, sort of like the Darkstar. It does not have to be, as it is hidden by the "belly".

Ok, resolved. I am going to try and get the wing "kink" angle and distances. I am going to assume that the edges of the wings are coplaner, and that everything is symmetric. (not bad assumptions) There are not too many points to look at, I am going to compute distances, constrain everything to one plane and enforce some symmetric constraints. I hope it is possible.

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