Dude wrote:
1.5 seems a low enough number.

Do you have any links about hybrids? I was thinking you would have seperate
engines.



"gerrcoin" wrote in message
...

Dude wrote:

Anyone know the slowest speed at which a scram jet would likely be able

to

start?

It seems NASA is using a rocket booster to get to speed, which would

make me

think this idea is a bit less than practical for civilian use. Can't

see

the Concorde crowd signing up for a rocket powered plane, though I could

be

wrong. It would be neat if it worked at a low enough Mach that you could
build a workable SST.

OTOH using one for a cruise missile would be neat. Picture a third

world

dictator about to go on live TV. By the time the sycophant finishes the
introduction, the missile will have left CONUS in time to blast the

podium

before the "general and president for life" is finished blaming the US

for

everything bad in his little banana republic!




IIRC they only get going at around mach 5 or so.

Rockets are used at the moment but eventually the idea is to use a
hybrid engine with a conventional engine to get it up to ramjet speeds
(mach 1.5-3.5), then the ramjet to 3.5 or so and then fire up the
scramjet. Each of these engine phases will have defined altitudes as
well of course.



That's only where the ramjet or rocket picks up. The scramjet itself
cannot fire up below about mach 5 and needs to be in the upper atmosphere.

I can't find much info on hybrid engines, mainly because they don't
exist yet-it's all just theory so far.

Try these though.
http://www.grc.nasa.gov/WWW/AERO/base/pdet.htm
http://science.howstuffworks.com/hypersonic-plane.htm