They custom-fitted *ducks* to the leading edges of the wings? That really is an interesting approach, although it didn't work too well for the US Airways flight out of NY last week...
NASA has announced the completion of a series of flight tests aimed at reducing the "sonic boom" effect, one of the major downsides of supersonic aircraft. Two custom-modified F-15 fighter jets were used in the test programme, referred to by NASA as Lift and Nozzle Change Effects on Tail Shock (LaNCETS*). Flying faster than …
Shkval rocket torpedos achieve this in water by blasting 'bubbles' in front of the nose to reduce drag markedly.
One such way in thinner fluid (air) might be to do this with on board APUs to produce high voltage with which to charge the leading edges and nose of the airframe to electrostatically push the denser air out of the way before the metal hits air...
I suspect this technique has been meddled with in certain non-civilian circles, and might be ready for prime time as a fuel saver and as a speed/commerce/noise control aid. Don't forget to beef up the transponders though...
I recall reading about some such thing in AW&ST a few years back...bolted onto one of my favorite flying wings...
Maybe boffins smarter than the rest of us can figure out how to adapt tech like this for the commercial sector, once they decide it is fit for release.
While there is certainly commercial benefit to such a technology, the U.S. Government would not be directly funding such technology unless there was some strategic value to it's Constitutional Role (i.e. protection of the United States of America.)
It would seem that a "boomless supersonic" stealth air vehicle would be a terrific asset to the U.S. military... radar would not see it coming and people might not be able to clearly tell when it had already passed over.
This is a terrific technology for military usage!
It is about time for another civil SST - supersonic means we won't have to put up with the Chavs for as many hours, we're at the destination quicker. No sonic boom means no further objection from the Greenies (unless it is a sin to travel quickly, think of the oil!)
There are military applications as well. Nothing quite announces the arrival of the USAF like a thunderous sonic boom, or better, several of them (the sound of FREEDOM!). So if they are on the way to go bomb bad guy X, even though the airplanes are invisible to radar, the people they overfly can still HEAR them and will realize that stuff is about to hit the fan, so they can phone ahead and their buddies will have a few moments to go hide. If the bad guys can't see them or hear them, then they're hosed . . . or are we a gentler, kinder nation now that Obama is in? ("Dear bad guy, please meet us for latte and cluster bombing at high noon.")
Personally, I like sonic booms. They tell me that our Air Force is awake, and watching out for us. Or at least flying around and looking like they are awake. Or something.
David Halko wrote: While there is certainly commercial benefit to such a technology, the U.S. Government would not be directly funding such technology unless there was some strategic value to it's Constitutional Role (i.e. protection of the United States of America.)
This is not true. The United States Government funds lots of stuff which is really just useless junk and many in the military will tell you that. The common theme that surfaces in unnecessary ventures is " jobs programs" for friends and family. You would be surprised how many such jobs and companies exist here geared towards jobs. The proverbial tail wagging the dog. It's a funny turning of supply and demand on its head.
One of the (many!) objections to wind farms is the noise of the damn things when going at a good lick. I understand this is in no small measure due to the tip velocity approaching that of the speed of sound? I'll be corrected, obviously. If the noise from the end of the blade can be diminished then the damn things may be come less noise at current velcoities or be permitted to spin faster before feathering becomes necessary. This shows how much/little I know.... !
Pass me my patent lawyer...
... was sufficient that the mighty Mach-2 airliner was largely restricted to subsonic speeds when over land, and meant that the London-New York route was the only one it could routinely serve.
Or, rather, that this was allegedly used as an excuse by the US air industry who hadn't been able to build their own SST and wanted to make it as commercially unavailable as possible, so they got their Government to force it to slow to sub-sonic speeds whenever they could.
Supercavitation is solving the problem of high friction between the water and the surface of the weapon. While a supersonic aircraft feels the effect of air friction it is nowhere near the limiting factor in its speed nor does it have anything to do with the sonic boom.
A sonic boom comes about because air is getting compressed ahead of the aircraft faster than it can get out of the way. The release of the compression waves behind the A/C is where the sonic boom comes from.
Changing the geometry of trailing structures - engines being the worst offender, the wings less so - helps the air compression waves release more gently.
This could find broad application commercially in several respects - reduction of noise in helicopters (rotor tips are usually supersonic), the windmills noted above, turbine blades, and so on.
"This could find broad application commercially in several respects - reduction of noise in helicopters (rotor tips are usually supersonic), the windmills noted above, turbine blades, and so on."
I believe this to be false - the major limiting factor in helicopter top speed is that as the speed of the copter + the speed of the leading rotor blade crosses the sound barrier, there is a catastrophic loss in lift generated. Couple this with retreating blade stall and you have a bird in trouble.
The characteristic "chop chop" sound of a helicopter is created by interacting tip vortices between the main rotor and tail rotor. This is why fancy NOTAR helicopters are used in cities, as they are quieter (and safer, with no tail rotor to worry about striking buildings).
Biting the hand that feeds IT © 1998–2020