USAF Launch Supersonic Bomb Firing Technology

coondoggie writes "Boeing and the US Air Force today said they have tested new technology that for the first time will let military aircraft launch bombs from aircraft moving at supersonic speeds. Researchers from Boeing Phantom Works and the Air Force Research Laboratory used a rocket sled in combination with what researchers called "active flow control" to successfully release a smart bomb known as MK-82 Joint Direct Attack Munition Standard Test Vehicle (JDAM) at a speed of about Mach 2 from a weapons bay with a size approximating that of the U.S. Air Force B-1 bomber, Boeing said. Active flow control is a tandem array of microjets upstream of the weapons bay that, when fired reduces the unsteady pressures inside the bay and modifies the flow outside to ensure the JDAM munition travels out of the bay correctly."

Comments

Re:This is very handy

[gujo-odori]

It's not a matter of how fast a target on the ground may move. It's a matter of how fast:

A) SAMs move
B) Enemy fighters aircraft move

If a bomber can fly by at Mach 2 at a high altitude and kick out its load of smart bombs, it becomes much harder to hit it with either a SAM or an air-launched missile. Let's say you make your bombing run at 40,000 feet going Mach 2 and a SAM battery a few miles away takes a shot at you. You kick out the bombs and firewall the throttle for any more speed you can get, and punch out chaff. The SAM is going maybe Mach 5 and you're maybe now at Mach 2.5. At a closure rate of only Mach 2.5, the SAM may run out of fuel before it reaches you, even if it doesn't get fooled by the chaff. If you'd had to slow down to sub-sonic speeds to make your bombing run, the SAM would have a much better chance of catching you.

If there is a CAP up, it's going to have a lot more trouble catching and firing on a bomber going Mach 2 than a bomber going Mach .7.

While these have not been particularly great threats recently (I believe the Viet Nam War was the last time an American heavy bomber was brought down by enemy fire), it wouldn't be wise to assume that the situation will always remain this way, so it's good to have that technology in our back pockets.

Even at lower altitudes, that would take a lot of light anti-aircraft systems off the table, and at least make it harder even for large SAM systems. Imagine being a guy with a shoulder-fired AA missile trying to get a bead on something going at Mach 2. Even if you get a successful lock on it and fire, it's unlikely your missile will be able to catch it even if it's on a low-level bombing run (something I wouldn't expect a B-2 to do, anyway).

Very very incorrect.

[Rank_Tyro]

The YF-12was a high altitude and high speed interceptor. It fired Air Intercept Missiles (AIM-7's)which are already aircraft in their own right. It did not drop free fall munitions at high speed.

This current little trick is probably a proof of concept for a change to the F-22, which carries free fall bombs such as the JADM in a recessed bomb bay. The B-1b can only do about Mach 1.25 at altitude where the air is thinner. The B-1b was designed as low level penetrator to sneak under Soviet radars. With the end of the cold war, the B-1b started taking over as a high altitude bomber with GPS guided weapons, and not risk itself to ground fire to drop.

The F-22 can cruise at Mach 2 without using afterburners, and I believe it can only carry two Mk-82 JADM weapons. The ability to fly in at Mach 2 while being practically invisible to radar, AND not having to slow down to deploy weapons would be a huge advantage.

Re:Very very incorrect.

[TopSpin]

The F-22 can cruise at Mach 2 without using afterburners The F-22 can not 'cruise' at Mach 2. That would be even more buck rogers than the aircraft is already. Exceeding Mach 2 in an F-22 requires afterburners and this, in the parlance of military aircraft, is not 'cruise.' What an F-22 can do is supercruise (exceed Mach 1 without afterburners, thus high fuel efficiencies which means good range and therefore viable in bombing missions) at about Mach 1.7.

The F-22 can dogfight (maneuver at high-G and operate weapons) above Mach 1 which is a major advantage as most of it's contemporaries must be below Mach 1 to do much more than cover ground. Dropping JDAMS at high speed and altitude is another huge advantage which is, as you speculate, what this is probably intended to validate.

Re:Very very incorrect.

[tjstork]

I've been to the F-22 web site, its really nice. But you should check out this:

http://www.airplanes.com/forums/military-aircraft/1411-mach-2-0-supercruise-60-000ft-altitude.html

There, you have a claim by a Major Robert Garland to have flown the F-22 at Mach 2 in level flight.

If you google around, you'll find Air Force guys saying that this plane will do Mach 2.5, and, more than a few people have pointed out that the F-22 has a better thrust to weight ratio than the SR-71... thus, all things being equal, this ought to be one fast bird.

Re:Very very incorrect.

[YrWrstNtmr]

Rumor has it some laser guided bombs were filled with cement

Not rumor, fact.

A 2000lb guided rock hitting a particular vehicle/tank is just as effective as a 2000lb MK-84.

In case anyone was wondering...

[palegray.net]

The tagging beta includes the word sopwith, a reference to "Sopwith Camel", a game I used to place on an 8086 box as a kid :). Your goal was to drop bombs on ground targets in a simplistic side-scroller sort of map. You can install a modern-day Linux version (pretty close to the original) by doing "sudo apt-get install sopwith" on Debian-based distros.

Maybe not as much fun as dropping real bombs out of a supersonic jet, but pretty darn close :).

Re:*sigh*

[Blakey Rat]

Why do you assume that investing in defense technology does *not* help the people of the US?

As I see it, any enemy we'd have to use this against would be throwing ICBMs with nukes at us. Why the fuck are we building bigger and better and more expensive bombs when all of our operations are counter-terrorist ops?

You're right, we should be like France before WWII and just invest all our military spending on a single type of defense because it made sense when we started building it. How stupid of us to diversify!

(When France started building the Maginot Line, it was actually impossible for tanks at that time to cross through the forested regions they decided to leave undefended; by the time war actually broke out, tanks could do it with ease and the entire installation was useless.)

Fixed geometry inlets

[calidoscope]

Actually, it's not structural, it's more the fact that the air inlets are fixed rather than variable, so the engines can't get the optimal amount of air intake at different flight envelopes. Because of this, pushing the aircraft beyond mach 2.0 for any extended period of time will cause structural failures in the air intake.

The first sentence is correct, the second is not.

The problem with a fixed geometry inlet is that it is inefficient. At Mach 2.0 and above, a significant portion of the thrust from a properly designed inlet is coming from the inlet itself. The A-12/F-12/SR-71 cruising at Mach 3.0 gets between 55 and 60% of the total thrust from the inlet - this is accomplished by the positioning the shock wave just inside the inlet (the cons on the front of the engine can be moved in and out specifically for this purpose). One of the early issues with the Blackbirds was figuring out how to handle "unstarts" where the shock wave pops out of the inlet - and gives the crew a wild ride in the process - this was also a problem with the B-58.

The F-16 was also limited to Mach 2.0 because of the fixed geometry wing. OTOH, the F-104 was rated top speed was Mach 2.2, but it could easily achieve Mach 2.4, but at the cost of weakening the aluminum alloy in the airframe.