GE4 Turbojet (Boeing 2207 SST)

[overscan]

From Flying Review International July 1970

 

[Sentinel Chicken]

What portions or components of the J93 went into the GE4? For the longest time I think the GE4 held the record for jet engine thrust until the modern high-bypass ration turbofans came along.

 

[overscan]

GE4/J5P
Type: Single-shaft axial turbojet with afterburner.
Intake: Annular, comprising front structural frame with eight radial struts supporting compressor front bearing housing.
Compressor: Nine-stage axial single-shaft unit with variable incidence inlet guide vanes and stator vanes, giving large stall margin for inlet distortion tolerance. Front and rear groups of stators are individually actuated for starting airflow control and for high airflow capability at supersonic speeds. Rotor construction is combined drum-and-disc with thin-section centreless discs. No 1 disc is overhung on forward conical extension shaft supported by compressor front roller bearing. Rearward conical extension shaft attached to periphery of No 9 disc is supported by centre main ball thrust bearing. Thin-section air tube located on front and rear conical shafts, passes through disc centres. Compressor delivery diffuser is integral with mid-section structural frame supporting centre main bearing. All stator vanes carried on inner and outer swivel bearings, with inner support rings sealing against rotor inter-disc drums. For reduced weight, rotor blades in stages 1 to 4 are hollow diffusion-bonded titanium alloy, and stage 5 to 9 electro-chemically drilled superalloy. Pressure ratio 12-5:1, mass flow 633 lb/sec (287 kg/sec).
Combustor: Fully annular design of moderately high heat release rate with primary air annulus having multiple axial swirl cups.
Turbine: Two-stage axial unit with air-cooled cast alloy nozzle guide vanes and rotor blades. Thin-section centreless discs with arched inter-stage spacers. Rotor blades have dovetail root fittings and second stage blades are tip-shrouded. Forward conical extension shaft attached to periphery of stage 1 disc locates with compressor rear conical shaft at centre main ball thrust bearing. Rearward tubular shaft extension from stage 2 disc located in rear main roller bearing. Stage 2 nozzle guide vanes cantilever mounted from outer end, with seal onto interdisc spacer at inner end.
Exhaust System: Annular exhaust duct from turbine with rear structural frame, with radial/tangential struts, supporting curved centre cone and turbine rear bearing. Turbine entry temperature at T-O, in excess of 2,000°F (1,366°K).
Afterburner: Conventional system with four V-gutter flame stabilisers mounted on radial struts in exhaust duct. Two-stage fuel injection enables thrust modulation over full augmentor temperature range. Annular thermal shield protects duct wall between combustion zone and variable nozzle. Fuel supply manifold encased in external annulus around exhaust duct.
Exhaust Nozzle and Thrust Reverser: Two-stage nozzle with integral thrust reverser. Comprises variable area primary nozzle positioned by hydraulic actuators which also "overtravel" to act as reverser blocker. Long-section secondary shroud includes tertiary air inlet doors which open for low speed operation and can be selectively locked open for reverser operation. Secondary nozzle provides guided expansion of exhaust gases and is pressure-positioned for optimum area ratio. For reverse thrust, primary nozzle translates rearwards to expose thrust reverser ducts (tertiary air inlet doors), closing to form a block, thus directing gases forward through the ducts. Provision also for noise suppression.
Fuel Systems: Hydromechanical primary engine and afterburner fuel control systems.
Accessories: All engine controls and accessories housed in sealed compartment under front of engine cooled by normal circulation of fuel to protect from high temperature environment at supersonic cruise. Accessory drive is via bevel gear box in nose cone, driven-ofF front of compressor. Drive shafts for accessories and airframe purposes pass through front frame radial struts.
Dimensions:
Max diameter (over exhaust nozzle) 89.5 in (2,280 mm)
Length overall 308 in (7,823 mm)
Weight, dry: (Dependent on specific installational features) 11,300 lb (5,100 kg)
Performance Ratings: Max augmented T-O
67,000 lb (30, 390kg) st at 5,200 rpm Max augmented T-O
50,500 lb (22,900 kg) st at 5,200 rpm Max flight conditions
Mach 2.7 at 82,000 ft (24,994 m)
Cruise at Mach 2.7 and 65,000 ft (19,812 m) 15,000 lb (6,804 kg)
Specific Fuel Consumption:
At cruise rating 1.50 lb/lb/hr (1.50 kg/kg/hr)

Flying Review International, Dec 1969

 

[Archibald]

Just a question : was this engine tested ? This would mean that something of the american SST existed for REAL...

 

[elmayerle]

This engine saw lots of ground testing but was never, to the best of my knowledge, flight tested. I'm really not certain how they could have flight tested it in the supersonic region, anyway. The flight tests of the J93 utilized a pod that just barely fit under the B-58 carrying it and the GE4 was a larger engine.

 

[Overkiller]

I seem to recall that at one stage the XB70 was proposed as a possible supersonic tesbed for this engine.

I think there is reference to this in the excellent Tony Landis book on the XB70, I think the idea was to replace several of the YJ93's on one side with a single GE4?

One thing I do find extraordinary about this engine is that it appears to have disappeared without a trace, I find it hard to believe that such a powerful engine simply found no application whatsoever!

A few years ago there were some allegations on the FAS website regarding the alleged "Brilliant Buzzard" project where it was speculated that the powerplant could well have been the GE4.

While on the subject of SST powerplants, does anyone have any info whatsoever on P&W's loser to the GE4?

 

[Archibald]

Maybe using a concorde as testbed ? :
I'm asking if it would have been possible fitting the enigne on a B-58, not on the J-93 pod but maybe on a wing pylon (deleting the two J-79 on the same side). Something dangerous to fly, that's sure!

 

[elmayerle]

While on the subject of SST powerplants, does anyone have any info whatsoever on P&W's loser to the GE4?

Pratt & Whitney's engine was the JFT20, an afterburning two-spool turbofan that shared technology with the JFT22 (F100/F401) that developed from the experimental JTF16 engine. When the SST mockup was in a museum in Kissimee, Florida, they had a JTF20 engine there on loan from P&W.

 

[sferrin]

Couple of pics from the test stand.

 

[RareBird]

This engine saw lots of ground testing but was never, to the best of my knowledge, flight tested. I'm really not certain how they could have flight tested it in the supersonic region, anyway. The flight tests of the J93 utilized a pod that just barely fit under the B-58 carrying it and the GE4 was a larger engine.

Though the B-58 did get the pod fitted and pictures where captured , it never was fired up, never tested with the B-58

 

[KJ_Lesnick]

While on the subject of SST powerplants, does anyone have any info whatsoever on P&W's loser to the GE4?

The JTF-17A -- it was a twin-spool, low-bypass duct-burning turbofan (bypass ratio: 1.3 to 1). It's dry thrust output seemed to point to figures around 39,000 lbf (I have heard claims of figures as high as 53,000 lbf dry, but any reliable sources about the SST program do not indicate these figures indicating that, most likely, the 53,000 lbf figure is not reliable or accurate) with afterburning thrust on the order of 61,000 lbf. The engine had no inlet guide-vane, and from what I remember had a 3-stage fan, a 6-stage HP compressor, and an annular combustion chamber.

Pratt & Whitney's engine was the JFT20, an afterburning two-spool turbofan that shared technology with the JFT22 (F100/F401) that developed from the experimental JTF16 engine. When the SST mockup was in a museum in Kissimee, Florida, they had a JTF20 engine there on loan from P&W.

Pratt and Whitney's contender was the JTF-17A -- I have never heard of the JTF-20 being used for P&W competitor to the GE-4?


Kendra Lesnick

 

[sferrin]

Another one.

 

[KJ_Lesnick]

Sentinel Chicken,

I can tell you the air-cooling scheme seems to have been incorporated, the hollow-turbine blades with holes drilled in the back of the first (turbine) stage as well, as well as variable-guide-vanes. The engine also has an annular combustion-chamber like the J-93.

It also has characteristics from the GE-1 (which I actually know very little about, other than it had 14-stages, which I read in one of Bill Gunston's engine books) as well.


Kendra Lesnick

 

[KJ_Lesnick]

overscan,

I found a STINET link which sheds some light on the nozzle-design and sound-suppression technology to be incorporated into it's configuration
URL: http://stinet.dtic.mil/cgi-bin/GetTRDoc?AD=AD907109

 

[Archibald]

I seem to recall that at one stage the XB70 was proposed as a possible supersonic tesbed for this engine.

I think there is reference to this in the excellent Tony Landis book on the XB70, I think the idea was to replace several of the YJ93's on one side with a single GE4?

One thing I do find extraordinary about this engine is that it appears to have disappeared without a trace, I find it hard to believe that such a powerful engine simply found no application whatsoever!

A few years ago there were some allegations on the FAS website regarding the alleged "Brilliant Buzzard" project where it was speculated that the powerplant could well have been the GE4.

While on the subject of SST powerplants, does anyone have any info whatsoever on P&W's loser to the GE4?

Four years later...

B-52 projected testbed for GE4
http://books.google.fr/books?id=wm8gAAAAMAAJ&q=%22General+electric%22GE4+%22test+bed%22+B-52&dq=%22General+electric%22GE4+%22test+bed%22+B-52&hl=fr&ei=SiesTKqFMoTIswb434S1BA&sa=X&oi=book_result&ct=result&resnum=2&ved=0CDUQ6AEwAQ

XB-70 testbed for GE4
http://books.google.fr/books?id=jaJTAAAAMAAJ&q=%22SST+engine+flight+testing%22vehicle+environment&dq=%22SST+engine+flight+testing%22vehicle+environment&hl=fr&ei=XSmsTN7RKdDBswaOrc2dBA&sa=X&oi=book_result&ct=result&resnum=1&ved=0CDYQ6AEwAA

No in flight test bed for GE4
http://books.google.fr/books?ei=hiisTKOhKcLDswbn2qy8BA&ct=result&id=TEogAAAAMAAJ&dq=%22XB-70%22GE4+testbed&q=GE4

google books is quite useful

 

[AeroFranz]

I believe the National Air and Space museum had one in their storage facility at Garber. Maybe we'll see it one day when they move everything to the new hangar at Udvar-Hazy.

 

[Mike OTDP]

I believe the National Air and Space museum had one in their storage facility at Garber. Maybe we'll see it one day when they move everything to the new hangar at Udvar-Hazy.

They did...and I think it's now on display.

 

[Sundog]

This is a re-post from within a seperate SST thread we have on U.S. SST's. I'm not sure if you want a seperate thread for the PW engine, since you also have this thread listed as Boeing 2707 SST.

GE 2707 Airframe Engine Technical Agreement

PW 2707 Airframe Engine Technical Agreement

The GE pdf is a bit tough to read, because all of the text is double imaged. Maybe someone here knows of a clean copy. There looks to be some good engine data in these. I've been doing some research, trying to find some engine decks or the most jet engine data I can find. I'm not sure this goes here. If we start digging into this more, maybe we should have a separate section for propulsion?

Anyway, enjoy.

 

[Caravellarella]

This is a re-post from within a seperate SST thread we have on U.S. SST's. I'm not sure if you want a seperate thread for the PW engine, since you also have this thread listed as Boeing 2707 SST.

Probably a very good idea Sundog; the existing SST topic is disparate, nonsensical and confusing beyond belief......

Terry (Caravellarella)

 

[Graham1973]

Found a video on YouTube of the engine being ground-tested. No sound and sadly no details of the original source.

https://www.youtube.com/watch?v=G-NfLoEv1xE

 

[sferrin]

I just stumbled upon it on youtube one day. Thought for sure I'd posted it before here. ???

 

[GeorgeA]

Tremendously in-depth doc (571 pages) on the GE4, with lots of detail on design and construction:

http://www.dtic.mil/dtic/tr/fulltext/u2/378484.pdf

And, a Boeing comparison of the GE4 and JTF17 (with respect to the 2707-200):

http://www.dtic.mil/dtic/tr/fulltext/u2/378498.pdf

 

[Johnbr]

The mock-up

 

[aeroengineer1]

I can confirm that this engine still exists. It was not scrapped out. It is a massive engine.