Have any true turboramjets ever been built and/or flown?

Kryptid

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Although I was able to find some references to turboramjets using the search function, they all seemed to refer to unbuilt projects and/or the J58.

(1) I've seen the J58 referred to as a turboramjet, but I've also seen people claiming that it was not a "true" turboramjet. What, if any, differences are there between the two engine types? Would the propulsion system on the Nord 1500-2 Griffon II be considered a turboramjet or would it be considered as having two separate engines?

(2) Disregarding the above examples, have any other engines ever actually been constructed that could be considered turboramjets? Have any of these turboramjets been equipped to aircraft that actually flew (experimental or otherwise)?
 
Semantics, dear boy, semantics.

J58 - bypass turbojet for want of a better term as far as I'm concerned.

Bristol Siddeley referred to their engines with common intakes but different jetpipes as 'combination engines' as they had separate jet pipes.

Does the the Griffon II have separate jetpipes, despite it looking like it has only one?

Chris
 
As to the question of whether any all-the-way TRJ - in which the turbine component is shut down, as in the XF-103 - has flown, I would say that I don't know.

The Atar jet engine in the Griffon continued to produce power - 20 per cent of the total at Mach 2, according to Colliat. http://jpcolliat.free.fr/griffon/griffon-2.htm

Most of the air in the J58 passes through the engine, which compresses it - that energy is recovered as thrust in the afterburner and final nozzle. The inventor, Bob Abernethy, has claimed that his boss did not realize that the name given to it in the patent - a "recover bleed air" engine - was also Abernethy's initials until it was too late to change it.
 
I think that the REX I II and III engines were turboramjet.
 
Per lack of a better thread... found lots of information on forgotten turboramjet projects.


Appropriate engines were selected for all of the candidate flight facilities, and installed performance of these engines was determined. The selected engines satisfy the basic Phase I premise that propulsion for the flight facilities be commensurate with the 1975 state-of-the-art. Six rocket engines, two turbojets, two turboramJets, one ramjet, one

scramjet, and two boosters were selected:

o Rockets: LR-129, Bell 8258, J-2S, H-1D (from: RHEINBERRY, Agena, and Saturns)

o Turbojets: YJ93-3, F100-GE-100 (modified to H2 fuel)

o TurboramJets: GE14/JZ8 (JP fuel), GE5/JZ6C (H2 fuel)

o Ramjet : MA145-XCA​

...​

-Report SS-65-2, GE5/JZ6 - Study C - General Electric Company, Flight Propulsion Division, December 1965 – CONFIDENTIAL

-Apel , G. F .; and Hines , R. W .: Estimated Performance of a Mach 8.0 Hydrogen Fueled Wrap - Around Turboramjet (SWAT - 201B). TDM-2001, Pratt & Whitney Aircraft , Jan. 4 , 1967

-Variable Cycle TurboramJet GE14/JZ8, Preliminary Performance and Installation Manual - GE Report, USAF Contract AF33615-69-6-1245, September 1969 – CONFIDENTIAL​

...


A study was performed to evaluate candidate turbojet/ramjet engines. The performance characteristics of the two leading candidates, the P&W SWAT-201A and the GE5/JZ6, are compared. The General Electric GE5/JZ6 advanced hydrogen fueled turboramjet engine was selected due to its superior climb/acceleration thrust performance and subsonic throttled specific fuel consumption.​

For the speed range up to Mach 4.5, the JP-fueled GE14/JZ8 was chosen. The data presented is for two design conditions of the GE14/JZ8 engine. The data in the lower curve represents an engine for Mach 4.5 with a pressure of 46 psia at a cruise altitude of 90,000 feet.​

For the speed range up to Mach 5–8, the GE5/JZ6C fueled by LH2 was selected. The engines operate the turbojet to it maximum allowable speed per the engine specification: Mach 3.5 for the JZ8 and Mach 3.75 for the JZ6C. The ramjet is operated from Mach 1.0 to cruise speed. The JZ8 is air-cooled throughout, while the JZ6C is fuel-cooled.​

Both the GE14/JZ8 and the P&W SWAT-201B engines are wraparound turboramjets. The P&W version was selected for use in this study program for several reasons. The primary reason was that it offered higher thrust per frontal area at sea level static conditions. In addition, it was designed to operate to Mach 8, whereas the GE engine was limited to Mach 4.5. Finally, the SWAT-201B was provided with the capability of independently scaling the ramjet compared to the turbojet; the GE engine was not.​

...​

To provide a near term technology prototype aircraft, a Mach 6 airbreathing configuration was selected. This vehicle, a turboramjet powered aircraft, provides capability for technology demonstration of advanced airbreathing propulsion systems, as well as a broad spectrum of research applicable to the defined potential operational systems. The vehicle is designed for steady state cruise at Mach 6 for five (5) minutes, operates in a conventional ground takeoff mode, and is manned. It employs the existing Pratt and Whitney J58 JP fueled turbojet engine together with a LH2 fueled wrap around ramjet modification. This will provide early research on a near term turboramjet engine. The engine selected is the P&W STRJ11A-27, which employs an existing, currently in use, JP fueled, J58 turbojet engine modified to include a wraparound hydrogen fueled annular ramjet.

Engine Selection - In selecting the engine for this vehicle, two sequential tasks were involved. First, a choice was made between using an advanced technology TRJ engine, or an engine which would incorporate an existing turbojet core and require developing only the ramjet subsystem (near-term technology). Phase I results indicated that the selection of an advanced TRJ engine would necessitate large engine development costs and thereby increase the cost of the overall program significantly.

At the same time, both Phase I and Phase II results point to the research value to be gained by flight experience with advanced airbreathing systems. To reduce the engine development costs and preclude pacing the aircraft development to that of an advanced engine, the near-term technology approach was selected. Having made this decision, the second task involved selecting the turbojet core to be employed from existing turbojet engines. Five candidate turbojet engines were considered: J58, F-100, GE4/J5P, J93, and J97. The selection was based on thrust-to-weight ratio, thrust, availability, and maximum Mach number capability. Three engines--the GE4/J5P, J93, and J97--were eliminated. In choosing between the J58 and F-100, a comparison was made of the thrust-to-weight characteristics of the two engines across the applicable speed range. The J58 was selected as the core turbojet for the basic Mach 6 based on the combination of a higher T/W at high supersonic speeds and a higher maximum Mach number capability. Engine modifications include using a fixed geometry convergent nozzle and closure doors to seal off the turbojet at flight speeds above Mach 3.5. The regeneratively cooled ramjet burns LH2 fuel and uses a variable geometry convergent-divergent nozzle. The ramjet size as defined in the engine specification was used for the propulsion system of the Mach 6 vehicle, and resulted in satisfactory performance without need for scaling.​

From a whole bunch of NASA documents - attached to this post.

So - seems the SR-71, SST, Valkyrie and F-15 engines at some point were in a competition to became a turboramjet core. But what was the J97 ? it was part of General Electric prolific family of advanced engines, small and large, supersonic and subsonic: among them the J101 / 404 / 414. J97 was created for the Ryan AQM-91 COMPASS ARROW stealth drone to fly above 80 000 ft - to the PRC Lop Nur nuclear test range in Xijiang and back. In 1968 !
 

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