120000 ft altitude high speed propeller aircraft based on turbocompound Jumo diesel

[mvdmitri]

Interesting 1992 concept propeller aircraft based on turbocompound opposed piston variable cycle very high compression ratio diesel engine (Jumo design) with the ducted fan intercooler.


'A preliminary design and analysis of an advanced heat-rejection system for an extreme altitude advanced variable cycle diesel engine installed in a high-altitude advanced research platform'

http://hdl.handle.net/2060/19920020184

Aircraft is designed for maximum fuel efficiency at 100,000 ft and maximum cruising altitude 120,000ft at speed 0.7 Mach (487 mph at 120kft).
Range 6000 nautical miles.
12 blade two speed propeller diameter -34 ft
1200 hp powerplant net shaft thermal efficiency is over 60% at 90-100 kft.
Wingspan - 273 ft
Takeoff weight -16,000 ft
Payload - 1,000 ft.

 

[NVSMITH]

-I was out of touch and/or out of the country from 1990 to 1998. We didn't even have reliable e-mail and the internet we know today didn't exist. When I got back to CONUS I reestablished contact with a guy who was an honest to goodness rocket scientist, a physicist. One of the projects he was working on, unclassified, was similar to what mvdmitri posted but with an interesting twist: instead of metal many of the engine components were to be made of ceramic. Evidently this was to minimize the expansion/contraction properties of metal. As i recall the concept the platform wasn't going to be powered 24 hours/day; maybe that meant flying on one engine vice two.
-Never heard anything more on the topic. I thought the bit about ceramic component engines was neat.

 

[sotaro]

-I was out of touch and/or out of the country from 1990 to 1998. We didn't even have reliable e-mail and the internet we know today didn't exist. When I got back to CONUS I reestablished contact with a guy who was an honest to goodness rocket scientist, a physicist. One of the projects he was working on, unclassified, was similar to what mvdmitri posted but with an interesting twist: instead of metal many of the engine components were to be made of ceramic. Evidently this was to minimize the expansion/contraction properties of metal. As i recall the concept the platform wasn't going to be powered 24 hours/day; maybe that meant flying on one engine vice two.
-Never heard anything more on the topic. I thought the bit about ceramic component engines was neat.

Ceramic engine components might allow higher temperatures and reduce cooling system requirements as well as increase efficiency. I noticed a possible 80:1 compression ratio. Perhaps, expansion ratio might be more the goal.