>No, more like it will be a long time before a combined cycle ramjet will be practical or efficient.
Dan, designs that lead the way go back to the 1950s!
Marquardt XRJ59-MA-3 (a pure ramjet) drove the X-7 in flight to almost 3000 mph (Mach 4.31) and long endurance
ground runs equiv. to flght 3 times around the world was successfully done in 1958-1959!
Marquardt MA-51 Hyperjet - an engine with integrated rocket/ramjet in test flights from 1958-1961, in 12 in
diameter config. (ie: small) demo'd static thrust (rocket) as well as accel. to hypersonic velocites after
ramjet takeover from rocket at Mach 3.2.
Marquardt MA177XAA - LASRM (Low Altitude Short Range Missile) - an integral rocket ramjet, solid rocket,
with hydrocarbon fuel for ramjet - low altitude flight test accomplished and tech. feasability demo'd. and
program lasted from 1963-1969.
Marquardt MA-24XEA - ramjet for Mach 4 cruise at 90K ft. Takeover at Mach 2, accel to Mach 4. Program
dates 1959-1959.
Marquardt MA107-XGA - H2 fuelled, Mach 8 at 120K ft, and Mach 3 at 60 K ft. Used regen cooling of
of airframe coooled H2.
Marquardt SERJ - 176 E -4B, a combined cycle with merits of turbofan, rocket, and ramjet able to operate
from sea level static to Mach 4.5 range. Proposed for Navy ADLI - Advanced Deck Launched Interceptor,
and USAF AMI (Advanced Manned Interceptor) pgms. Noted in 1970 that completed ground test technology
programs provide a suitable technology level for a credible prelim. engine design.
These are just the Marquardt "pieces" of tech, as there were others, and in the end, the problem was
getting the military to step up to the plate.
So don't say that it will take a long time before the tech will be practical or efficient.
This doesn't even talk to the modern designs for turbojets or turbofan ramjets that have been proposed
and even tested.
