Mach 6 at Low Altitude: Craft Skin, Booms & Visibility

[Aero51]

From the perspective of a military power: The less an enemy knows about my capabilities, the better. Personally, I think the new front will be electronic warfare. This is expected considering everything we use nowadays requires a computer.

 

[etudiant]

From the perspective of a military power: The less an enemy knows about my capabilities, the better. Personally, I think the new front will be electronic warfare. This is expected considering everything we use nowadays requires a computer.

It seems clear that conflicts between more advanced states are currently conducted by computer hacks (Stuxnet for instance) rather than by bombs.
That said, there are few secrets about nuclear weapons effects, because the details were disseminated so widely during the civil defense effort of the 1950s and 1960s, so there is not much to hide there. However, there have been hints, notably from the late US nuclear weapon designer Ted Taylor, that it was possible to design nuclear devices to deliver a directed blast. Such a feature would greatly increase the military utility of nuclear weapons.

 

[Aaronvan]

There are videos of a Sprint missle launch going from 0 to mach 10 in a few seconds. It's white hot after only a few seconds at that speed. It had a range of about 25 miles and a typical intercept time was expected to be about 15 seconds.



There is information about the heat shield here:
http://srmsc.org/pdf/004431p0.pdf

Oh man, I love Sprint! You could cool it off with an acetylene torch!

 

[brenan]

... Good news is that the wings become unneccessary for lift, a shaped body would be ample, but control would be a challenge.

Ah - this is what was interesting me - could you or (or anyone) explain how flight works
without wings in such cases?
(any comments on the control issue would be interesting too)

 

[boneh3ad]

You can put just about anything at an angle of attack and it would fly, given enough forward velocity. If you strapped a rocket to a fridge and flew it at an angle, you could make it fly. Shapes like airfoils merely make flight more efficient at low velocities.

Once you reach supersonic speeds, camber and thickness to a surface no longer contribut a thing to lift, only drag. The most efficient supersonic airfoil is an infinitely thin flat plate at angle of attack, so most purely supersonic craft (e.g. many missiles) have no real need for wings. As long as they maintain an angle of attack they generate lift.

 

[brenan]

Yes this was what my earlier comment was about relating to cruise missiles - were they flying (with lift) or being constantly corrected for "falling". As far as I can tell the shaped body etudiant is alluding to is just a shape very similar to a wing. .i.e. nothing new or special just a merging of the body with the wing or shaping the body as a wing.

 

[etudiant]

Yes this was what my earlier comment was about relating to cruise missiles - were they flying (with lift) or being constantly corrected for "falling". As far as I can tell the shaped body etudiant is alluding to is just a shape very similar to a wing. .i.e. nothing new or special just a merging of the body with the wing or shaping the body as a wing.

You can get a sense of what lifting bodies from NASA look like here:
http://www.nasa.gov/centers/dryden/history/pastprojects/Lifting/index.html

 

[chasrob]

@etuciant: you're right, it makes more sense to expend more fuel to get up to altitude and accelerate to speed up there. I was reading about the hypersonic cruise missile Shaurya, and thought it was like most cruise missiles i was aware of, nap of the Earth hugging types. I thought that materials tech had advanced to the point where such profiles were possible, and wondered what those super-materials were and what shape the air frame took.

Although now I suppose the Shaurya first flies to 50km and dives into the target. Apparently the BrahMos sea skims at 3-4 meters doing M 3.