A Kludge

Hey, it's the Myasishchev Bounder!!!

Has anyone noticed that they just took the wing configuration from an old Russian supersonic bomber, the M-50 Bounder?

http://www.militaryfactory.com/aircraft/detail.asp?aircraft_id=537

Bah! Someone beat me to it!

Ah, the Hydrogen Religion again.

Project SUNTAN all over again. Pity Kelly Johnson isn't around to send the money back this time.....

What it is, is the Skylon air-breathing launcher, apparently without any changes. Not a swell idea for launching stuff into space, but it's got to be even worse for intercontinental passenger service.

Rand,

I'll understand if you can't divulge anything on your particular business venture at this time, but can you point to any articles or research on how one would (in theory) get rid of shockwaves and/or drag? I am not an aeronautics engineer so I'd be interested in a basic introduction to the concept.

Thanks for any links!

One thing to comment on here.

Hydrogen is no more an energy storage method than gasoline is. The only difference is that the energy stored in the gasoline was done a long time ago.

Also, H2O is a greenhouse gas, 20 times more powerful than CO2. However, the persistence of H2O in the atmosphere is measured in days or weeks, not decades. H20 has a tendency to precipitate when its density reaches a certain level.

However, the persistence of H2O in the atmosphere is measured in days or weeks, not decades. H20 has a tendency to precipitate when its density reaches a certain level.

This is true -- in the troposphere. As Rand pointed out, this plane would fly at 60,000 feet, where the relative humidity is normally quite low. The residence time of water at that altitude is considerably longer, and the natural rate of water injection there is considerably lower. So, anthropogenic effects would be easier to produce there than down here near the surface.

On the subject of all of this, anyone have any insights or knowledge of the outcome of the XB-70 project with regard to supersonic aerodynamics.

The way the story was told, the Air Force let it be known that they wanted a supersonic or perhaps even a supercruise (supersonic the whole way over, not just evading air defenses) bomber, and they got a number of impractical proposals owing to the fuel consumption problems of supersonic flight. On proposal was for a plane that had some ridiculously large drop tanks, and General Curtis LeMay was heard to exclaim, "That is not a bomber, that is a three ship (as in aircraft) formation!"

North American came along with a radically-different proposal, one in which the drag-inducing shock wave could be put to a good purpose -- generating lift. The concept was called compression lift and supposedly a supercruise aircraft could have higher (?) L/D ratios than a subsonic one.

The embodiment of compression lift in the XB-70 was 1) having the engines in one big pod under the wing, and 2) a variable geometry wing where enormous wing tip sections would droop downward -- these two features were supposed to channel the shock wave and create the compression lift. Sort of the aerodynamic version of the fictional Star Trek Warp Drive where the Warp Drive pods create a bubble of space-time that scoots the ship along.

They built two XB-70s. While these were designed as Mach 3+ aircraft, Ben Rich of Skunk Works fame derides the accomplishment to claim the SR-70 as the only Mach 3 supercruiser and claims the XB-70 to be Mach 2.5. In actuality, XB-70 #1 could go Mach 3, but it had the tendency to melt off the bonding of the steel honeycomb structure and injest part of the inlet structure into those very expensive engines, so they slapped a Mach 2.5 speed limit on it. XB-70 #2 was supposed to have been bonded so it didn't have that problem, but it had flight control problems stemming from a dihederal wing that was supposed to solve flight control problems of XB-70 #1. XB-70 #2 was lost in an accident resulting from a stupid photo op, killing chase pilot Joe Walker, one of the XB-70 crew and maiming the other.

So it is not clear how much test flight took place at Mach 3 supercruise or whether they got anywhere near the predicted fuel economy from compression lift -- anyone know? Two things were revealed by the XB-70 -- like the Mach 3+ SR-70, the XB-70 had serious issues with control of the engine inlets and something called an "unstart" where the shock wave didn't stay put. It was said that these unstarts were always major inflight emergencies that got your attention by uncommanded yaw that could slam your helmeted head against the side of the cockpit, and some remarked that a Mach 3 SST was a non-starter on account of un-starts.

The other thing they figured out was that Mach 3 supercruise would generate huge sonic boom swaths. Was this a feature of the compression lift or just of that big and that fast a plane?

The final thing was that while the XB-70 was used to get test data on the SST flight profile, the Boeing SST didn't look like it had any of the compression lift features -- the single engine pod with multi engines, the wing tip droops. Was compression lift one big "unstart" based on unmet expectation in the XB-70 program?

Hmmm. Is shockfree for public discussion?

Note that the repeats were due to getting error pages back from commment.cgi and then retrying. You might still have some debugging to do :-)

Is shockfree for public discussion?

I've been discussing it publicly for years. The patents are in place.

Note that the repeats were due to getting error pages back from commment.cgi and then retrying. You might still have some debugging to do :-)

Yes, that's why I have the warning, right under "Leave a comment..."

Shockfree - a bit of googling turns up this project from Vehicle Research Corporation. Dale and Rand, is this what you're referring to?

Yes, that is the concept. I hadn't realized that that paper was on the web. We'll have to add it to the reference list. Note however that it's not VRC work--it's a review of VRC work, and only a cursory analytical one.

I seem to be developing the habit of injecting sci-fi short stories and novels into these threads.

A few months (a year or two?) ago I read as story in analog that was about (and may have been titled) a supersonic blimp. The idea was, as Rand mentions, to have a non-shock wave producing wing/fuselage, which would unfortunately provide no lift. Lift, then was to be provided using helium. It was a humor piece, full of exaggerated bureaucrats and skunk work operations, and quite a good read. I was left with "I hadn't known before that you could go supersonic without a shock wave" and "that couldn't possibly work--could it?"

Clever idea using a jet curtain to reflect shock waves from the wing to reduce sonic boom and improve wing performance. But it seems to me that running your engines to produce such a curtain, multiple Mach factors faster than the aircraft, would use a lot of power, unless the curtain was very thin to use a small fraction of jet reaction mass.

...it seems to me that running your engines to produce such a curtain, multiple Mach factors faster than the aircraft, would use a lot of power, unless the curtain was very thin to use a small fraction of jet reaction mass.

Calculations indicate that you need about ten percent of the bleed air off the compressor, and you get thrust out of it, so the only losses are entropy getting it from the engine to the jet nozzle. These are relatively low, because it occurs at low velocity and high pressure.