Mulit-Cycle Subsonic / Supersonic / Pulse Detonation Expansion Engine

Votes: 5
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Multi-Mode Hybrid Subsonic/Supersonic/Pulse Detonation Combustion Engine System:

This engine functions as an Expansion-Cycle Turbojet for takeoffs and landings (for noise reasons). Then transitions through Pulse-Detonation Turbojet, Pulse-Detonation Ramjet, Supersonic-Combustion Ramjet, and Pulse-Detonation Rocket as it accelerates into earth orbit.

1) Propellants :
a) Fuel : JP-7
b) Oxidizer :
i) Atmospheric Operation : Air
ii) Exo-Atmospheric Operation : LOX
2) Uses Shared Intake system (similar to Lockheed-Martin SR-72).
a) Used to feed the axial compressor during Phase-1 (Expansion-Cycle Subsonic-Combustion Turbojet) & 2 (Expansion-Cycle Pulse-Detonation Turbojet) modes.
b) Diverts air into the compressor, and an openings are provided to divert air into the combustion chambers.
3) Uses expansion cycle turbo-machinery driven by regenerative cooling of combustion chambers (ala. REX-I/III)
a) Continuous Drive on Fuel and Hydraulic pumps.
b) Axial Compressor, oxidizer pump, and generator selectable by multi-plate clutches.
4) Combustor is a hybrid Thermally-Choked Ramjet/Scramjet and Aerodynamically Valved Pulsed Detonation engine :
a) Mode selection as follows:
i) Continuous-Combustion operation between Subsonic and Supersonic combustion is determined by which set of injectors along length of engine are delivering fuel.
ii) Pulse detonation mode operates by injecting fuel then using active ignition by laser in pulsed operation having 2 combustors .
b) Catalytic Regenerative cooling breaking down JP-7 Fuel into Ethylene and Ethane, using same alloy as Ergomash RD-180 engine.
i) Advantage this approach has for expansion cycle turbo-machinery is that as a result of the endothermically-driven, catalytic cracking of the JP-7 fuel.
(1) In addition to increasing the kinetic energy (temperature) and thus expansion of the fuel, you also increase the number of mols in the resultant gas stream to drive the turbo-machinery, generating more power for the fuel and oxidizer pumps.
c) Ignition for Pulse Detonation cycles uses a variant of the laser ignition system developed by Cummins Diesel and University of Colorado.
i) Uses multiple intersecting beams at an acute angle which individually is not sufficient to damage the lining of the combustion chamber, but at the intersection points are more than hot enough for ignition of the oxidizer/fuel mixture.
(1) Allows adjustment of ignition point along the axis of the combustion chamber.
ii) Optic ports made of fused quartz backed by AlON optical ceramic.
d) In Pulse Detonation Rocket mode, the intake is closed off, and oxidizer is provided by liquid-fueled rocket combustion chambers with sonic nozzles that run 'oxidizer-rich'. Thus Pulse Detonation Rocket mode is semi-staged-combustion in nature.
e) This is the critical technology to make a economically viable Single-Stage-To-Orbit Space-plane feasible.

5) Operating Profile :
Mode: Airspeed (in Knots): Altitude (in Feet) ISp: (in Lb/sec):
a) Expansion-Cycle Turbojet 0 - 720 0 - 30,000 3400 - 1900
b) Pulse-Detonation Turbojet 721 - 1,400 30,000 - 60,000 4200 - 3500
c) Pulse-Detonation Ramjet 1,401 - 4,000 60,000 - 90,000 2800 - 2500
d) Supersonic-Combustion Ramjet 4,001 - 7,200 90,000 - 120,000 1250 - 800
e) Pulse-Detonation Rocket 7,201 - 15,565 120,000 ft. - orbit 1000


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  • Name:
    Jeff Kavanaugh
  • Type of entry:
  • Profession:
    Information Technology, Amateur Inventor
  • Number of times previously entering contest:
  • Jeff is inspired by:
    This design was inspired by the perceived need for a more cost-effective, less maintenance intensive, and safer method of delivering payloads into low earth orbit. This is a modular, optionally-manned, reusable, Single-Stage-To-Orbit, Trans-Atmospheric Vehicle; to replace the Space Shuttle. Particularly after Challenger and Columbia...
  • Patent status: