Hypersonic Aircraft – Ram Jets

Ambience: Jet Aircraft

If you think that ramjets and scramjets are the stuff of science fiction, stay tuned. I’m Jim Metzner and this is the Pulse of the Planet. Propeller planes can reach speeds of up to 400 miles an hour, and jet planes are able to get to mach 3, or 3 times the speed of sound. Well, engineers at Dryden Flight Research Center are working on the next leap in aircraft technology, hypersonic flight. Project Manager Paul Reukauf.

“So, to go faster than about mach 3 to mach 4, or 3 times the speed of sound to 4 times the speed of sound, you have to have another propulsion device. One is a rocket motor, like they use on the space shuttle, and the other is a so-called ramjet or scramjet, which has no internal moving parts, and, consequently, you don’t have to worry about those parts heating up and coming apart. Scramjet stands for supersonic combustion ramjet. Ramjet was just a term that said that we didn’t have a compressor ahead of it, that we use the shockwaves to compress the air or ram the air into the engine. Well, when you talk about ramjets and scramjets, the reason that they don’t need moving parts is because you actually use the airplane and the shockwaves to do the work that the rotating machinery did in the turbojet. If you are judicious about the design of the airplane, you can actually use the shockwaves coming off the front of the airplane to compress the air before it goes into the engine. In a scramjet we never slow the air down slower than the speed of sound. The problem is that you have to ignite the fuel and burn it before it before it goes through the engine, and it’s moving at about 2,000 miles an hour, so that’s a pretty tough thing to do.”

Pulse of the Planet is made possible by the National Science Foundation, with additional support from NASA. I’m Jim Metzner.

Hypersonic Aircraft - Ram Jets

A Scramjet may sound like something out of a comic book, but it's the key to the next leap in aircraft technology.
Air Date:03/20/2007
Scientist:
Transcript:

Ambience: Jet Aircraft

If you think that ramjets and scramjets are the stuff of science fiction, stay tuned. I’m Jim Metzner and this is the Pulse of the Planet. Propeller planes can reach speeds of up to 400 miles an hour, and jet planes are able to get to mach 3, or 3 times the speed of sound. Well, engineers at Dryden Flight Research Center are working on the next leap in aircraft technology, hypersonic flight. Project Manager Paul Reukauf.

“So, to go faster than about mach 3 to mach 4, or 3 times the speed of sound to 4 times the speed of sound, you have to have another propulsion device. One is a rocket motor, like they use on the space shuttle, and the other is a so-called ramjet or scramjet, which has no internal moving parts, and, consequently, you don’t have to worry about those parts heating up and coming apart. Scramjet stands for supersonic combustion ramjet. Ramjet was just a term that said that we didn’t have a compressor ahead of it, that we use the shockwaves to compress the air or ram the air into the engine. Well, when you talk about ramjets and scramjets, the reason that they don’t need moving parts is because you actually use the airplane and the shockwaves to do the work that the rotating machinery did in the turbojet. If you are judicious about the design of the airplane, you can actually use the shockwaves coming off the front of the airplane to compress the air before it goes into the engine. In a scramjet we never slow the air down slower than the speed of sound. The problem is that you have to ignite the fuel and burn it before it before it goes through the engine, and it’s moving at about 2,000 miles an hour, so that’s a pretty tough thing to do.”

Pulse of the Planet is made possible by the National Science Foundation, with additional support from NASA. I’m Jim Metzner.