Free Republic
Browse · Search
News/Activism
Topics · Post Article

To: the_gospel_of_thomas
Unlike rockets, which must carry oxygen with them as a "combustor" to ignite the fuel supply, scramjets take oxygen from the atmosphere, offering a huge savings in aircraft weight, and researchers around the world would like to take advantage.

I see that knowledge of the subject matter is no impediment to finding a job. Where do they find these writers?

For those that are curious, a SCRAMJET (Supersonic Combustion Ramjet) is an engine that uses shockwaves created by the engine's internal geometry to compress the air entering it. The vehicle, of course, needs to be travelling at a speed which will produce shockwaves inside the engine. In contrast, a typical jet-engine has a rows of compressor blades and a turbine connected by a shaft which adds considerable weight. The SCRAMJET is, at the risk of over-simplifying, really just a hollow tube.

27 posted on 11/10/2004 10:22:55 AM PST by Ranxerox
[ Post Reply | Private Reply | To 1 | View Replies ]


To: Ranxerox

Actually you are describing a Ramjet. A Scramjet technically is a Supersonic Combustion Ramjet, thus a Ramjet where combusion is accomplished without the inlet airflow slowing down to subsonic velocities. Ramjet missiles have flown supersonically since the 50s (Bomarc), but when you don't have to slow the inlet airflow down to subsonic inside the engine, you can gain even faster exit flows, thus faster vehicle speeds.

The benefits of Ramjets and Scramjets over rocket engines is that you don't have to carry your oxidizer with you. Bad thing is that once you get to the upper atmoshere, you don't have much oxygen to scoop up. Going at high mach numbers in the lower atmosphere produces a lot of drag friction heating. And if your goal is to go orbital, you still have to reach exit velocity, which is a lot faster than any Scramjet can go.

Gee, I knew that degree in aerospace would be good for something after all. :)


43 posted on 11/10/2004 7:10:25 PM PST by anymouse
[ Post Reply | Private Reply | To 27 | View Replies ]

Free Republic
Browse · Search
News/Activism
Topics · Post Article


FreeRepublic, LLC, PO BOX 9771, FRESNO, CA 93794
FreeRepublic.com is powered by software copyright 2000-2008 John Robinson