Q about an experimental

Hello to the group. I just read a Google groups thread from a few years
ago, on the Allison V-1710 engine. Two of the posts included a reference
to a DARPA project to develop an engine for long range cruise missiles.
It used a diesel engine as its core. Can anyone provide information on
this project?
Thanks in advance

Me wrote in message ...
Hello to the group. I just read a Google groups thread from a few years
ago, on the Allison V-1710 engine. Two of the posts included a reference
to a DARPA project to develop an engine for long range cruise missiles.
It used a diesel engine as its core. Can anyone provide information on
this project?
Thanks in advance

IIRC, that was a turbocompound diesel engine, right?
Anyway, the only diesel engines that seem of military interest for
flight vehicles is micro-diesels for MAVs. D-STAR has made a 1.3hp
micro diesel that runs off JP-8 and 3% 2-stroke with no volatile
additives!
DARPA meanwhile is working on a scramjet-powered cruise missile while
EADS has proposals for air-breathing rocket-powered cruise missiles. I
don't know exactly what configuration EADS has adopted for their
stealth cruise missile.
Sorry I couldn't answer your question specifically... it was years
ago. However, I don't think a diesel powered cruise missile would be
practical in terms of power-to-weight ratio especially with the
materials and technology available today. There is always a group that
is trying to propose "cheap" vs "high-tech" solutions for future
offensive systems... but in the US the high-cost technology usually
wins out!

Rob

"Me" wrote in message
...
Hello to the group. I just read a Google groups thread from a few years
ago, on the Allison V-1710 engine. Two of the posts included a reference
to a DARPA project to develop an engine for long range cruise missiles.
It used a diesel engine as its core. Can anyone provide information on
this project?
Thanks in advance

You are probably referring to the Compound Cycle Turbine Engine (CCTE)
program which was a DARPA project back in the late '70s - early 80's. The
concept was a small turbofan engine with the combustor replaced with a
diesel engine. The intention was to have an ultra-efficient engine which
would greatly increase the range of the first generation cruise missiles.
Cycle studies showed that a 30% - 40% reduction in fuel burn (and a
corresponding increase in range) could be attained. There were several
unconventional concepts explored, including an eccentric turbine engine
where the high pressure and low pressure spools of the engine were offset
from each other.

Garrett had the contract for the CCTE and ran several single cylinder diesel
rigs to demonstrate the technology. No multicylinder or full engines were
ever developed. The DARPA contract finally ended in the mid-80's when the
cruise missile focus changed from low and slow missions to high and fast.
The Army funded the effort for a little while under the Compound Cycle
Engine (CCE) program to explore the application of this technology for
rotorcraft. But by the end of the '80s this was pretty much a dead
technology at least for aerospace applications.

Hope this helps

Mark Johnston