Looking for histories on the F100 and F101 engine development

[Jacky]

P&W proposed a program where new 275 pps Fans and LPTs would be produced and installed on current -229 engines for make -232 engines. The removed -229 fans and LPTs would be installed on -220/220E engine, creating the -220P, which would have operated the fans at the original 240 pps airflow, with a thrust rating in the 26-27k range, essentially recreating the original PW1128.

The PW1128 is the result of the F100 EMD project, and its thrust level is the same as the F110-GE-100. So why didn't the USAF directly adopt the PW1128 but instead used the PW1128 technology to develop the F100-PW-220? In addition, did the PW1128 really compete with the F110-GE-100 for the F-14 engine replacement project?

 

[F119Doctor]

What a shame about the F100-PW-232, I thought the F100-PW-232 would provide more dry thrust than the F110-GE-132 due to the lower bypass ratio. Also, does the F100-PW-232 have a Vmax mode like the F100-PW-220 to provide extra thrust(I know F100-PW-220 has Vmax mode, but but F100-PW-229 canceled this mode) ?

I heard that the F135 had a serious screech problem at low altitude and high speed in the early stages, which prevented the F135 from running at full power. Since the F135 is derived from the F119 engine, does that mean the F119 has the same problem at low altitude and high speed?

I don’t have the Mil power ratings of the -132 vs the -232, but I believe your bypass ratio comparison is correct.

I don’t know if the -232 would have had Vmax. The -220 was the same engine aerodynamically as the -100/-200, which had Vmax programmed into the EEC supervisory control, and this uptrimmed schedule was included in the -220 DEEC. The -229 could have easily incorporated it in its DEEC schedules, I assume the USAF decided there was not requirement for this capability.

Augmentor screech (high frequency combustion instability) and rumble (low frequency combustion instability) are often encountered during development, especially in the lower right corner where high ram pressures and AB fuel flows are encountered, with AB fuel flows running 2x sea level static conditions. It is common to limit AB fuel flow in the lower right corner to keep screech under control to prevent damage to engine hardware until tweeks to AB aero and fuel distribution tame the beast. Screech is difficult to predict and often requires iterative hardware / software changes and testing to arrive at a satisfactory solution.

 

[F119Doctor]

The PW1128 is the result of the F100 EMD project, and its thrust level is the same as the F110-GE-100. So why didn't the USAF directly adopt the PW1128 but instead used the PW1128 technology to develop the F100-PW-220? In addition, did the PW1128 really compete with the F110-GE-100 for the F-14 engine replacement project?

I think you are confusing the PW1128 with the F401, which was being developed concurrently with the F100-100 in the early 1970s and was intended for the F-14. The F401 had a larger fan than the F100, with an additional fan mounted core stage to add to core flow. The Navy stopped funding the F401 development after some difficulties were encountered in both the F401 and F100 testing.

The F100-220 maintained the aerodynamics as the -100/-200, but developed the increased life core module and DEEC full authority control system in the early to mid 1980s as part of the USAF Component Improvement Program (CIP) becoming the P&W competitor to the F110-100 in the USAF Alternate Engine Program. The Navy funded GE to stretch the F110 augmentor and a few other changes to fit the F-14 with the F110-400, finally realizing the performance potential promised by the never completed F401.

The PW1128, with its larger 3 stage fan and updated LPT, utilized the -220 core in the mid 1980s. The -229 Improved Performance Engine (IPE) developed a higher airflow compressor for the core module to enable the engine make the 29K IPE thrust target, competing with the GE F110-129, also developed under the IPE program in the late 1980s, early 1990s.

 

[Jacky]

I think you are confusing the PW1128 with the F401, which was being developed concurrently with the F100-100 in the early 1970s and was intended for the F-14. The F401 had a larger fan than the F100, with an additional fan mounted core stage to add to core flow. The Navy stopped funding the F401 development after some difficulties were encountered in both the F401 and F100 testing.

The F100-220 maintained the aerodynamics as the -100/-200, but developed the increased life core module and DEEC full authority control system in the early to mid 1980s as part of the USAF Component Improvement Program (CIP) becoming the P&W competitor to the F110-100 in the USAF Alternate Engine Program. The Navy funded GE to stretch the F110 augmentor and a few other changes to fit the F-14 with the F110-400, finally realizing the performance potential promised by the never completed F401.

The PW1128, with its larger 3 stage fan and updated LPT, utilized the -220 core in the mid 1980s. The -229 Improved Performance Engine (IPE) developed a higher airflow compressor for the core module to enable the engine make the 29K IPE thrust target, competing with the GE F110-129, also developed under the IPE program in the late 1980s, early 1990s.

No Sir, I am talking about PW1128 not F401. But I got an answer in the report "Department of Defense appropriations for fiscal year 1985,
hearings before a subcommittee of the Committee on Appropriations, United States Senate, Ninety-eighth Congress, second session, P515". Navy Secretary Lehman said that the progress of PW1128 lagged behind the needs of the Navy, so Navy chose F110.

 

[F119Doctor]

Thanks for that citation regarding the PW1128 for the F-14. Senator Wicker was from Connecticut and was a supporter of P&W.

Yes, the PW1128 would have had similar performance to the F110-400, which was very similar to the F110-100 that had already completed development for the USAF Alternate Engine Program in 1985.

The main change to the -400 was an extension duct between the engine fan ducts and the augmentor duct to stretch the engine to match the TF30 length and mounting points. However, the TF30 gearbox had provisions for mounting the aircraft hydraulic pumps and generators, while the F110 was not. This necessitated the need to develop a F-14 Aircraft Mounted Accessory Gearbox (AMAD), similar to the system used on the F-15 and F-16. In this link, it is described as a tandem gearbox https://www.ausairpower.net/PDF-A/engines.pdf

This AMAD / tandem gearbox system was not without its development challenges. Unique to carrier landings, the abrupt spin up of the main landing gear wheels causes an airframe flex ( I believe is is technically called “Twang” ) that caused motion between the two gearboxes with resulting damage. Obviously, this was corrected during development of the F-14B configuration.

 

[Sundog]

Just out of curiosity, could the F110 have been made to work in the F-111 as well? Or were the TF30s in the F-111 too different from those in the F-14 to have worked?

 

[aim9xray]

Just out of curiosity, could the F110 have been made to work in the F-111 as well? Or were the TF30s in the F-111 too different from those in the F-14 to have worked?

Speculatively, I think it would depend on three things; engine location (x axis, affecting weight and balance, Use the F110-400 with the long duct augmenter), fit/interference issues with accessories etc, and inlet/mass flow capacity (F-111F would be the best retrofit candidate; F-111A the worst).

 

[Colonial-Marine]

And UAE provided the funding for the -132. The USAF didn’t pay for the development of either the -132 or -232, beyond some initial R&D that lead to the design of the advanced fan concepts for both. The -132 had the advantage of the B-2 program funding the blisk fan development for the F118, which was then available for the -132.

And apparently some sort of royalties have to be paid to the UAE if another country were to use the F110-GE-132 or other specific Block 60 F-16 components? That may have seemed a shrewd move on the UAE's part at the time, but it seems to have made potential customers opt for the -129, and left the F-16E/F as something of an orphaned variant of the F-16 family. Despite all of the money they spent to help develop it they seem to now be ordering Rafales instead of more "Desert Falcons". Though that might be more due to politics than anything about the particular qualities of the relevant aircraft.

 

[F119Doctor]

Just out of curiosity, could the F110 have been made to work in the F-111 as well? Or were the TF30s in the F-111 too different from those in the F-14 to have worked?

The F110-400 could probably been made to work in the F-111. The TF30-P-3/-103 (A, C. and E models, P-7/-107 (FB-111A), and P-9/-109 (D model) were quite similar to the F-14 TF30 models (minus the fan containment in the -412A and -414). The AB nozzles were different , with the F-111 engines having Blow-in Door Ejector nozzle, and the F-14 engines having sliding segment iris nozzles.

The TF30-P-100/-111 engine in the F model was significantly modernized, increasing airflow from 240 PPS to 260 PPS with thrust up to the 25K range. Those figures are not much different than the F110-400.

In the mid-1990s, the USAF was looking for F-111F propulsion options. GE was recommending the F110-129 with -400 style modifications. P&W looked at the F100-229. Performance analysis showed both -129 and -229 provided better acceleration, but both engines had a lower top speed at both low altitude and high altitude conditions than the TF30-P-111. (I don’t know why, suspect higher bypass, lower OPR and TIT, and having the front half of the core compressor on the low rotor has something to do with it). P&W ended up proposing a scaled -229 augmentor & nozzle for the TF30-P-111, since the nozzle was driving the supportability issues, while the rest of the engine had plenty of life left. In the end, the USAF decided to retire the F-111 fleet, with the Australians keeping their F111C fleet going, creating their own hybrid engine configuration the TF30-P-108, combining parts from -107 and -109 engines retired from the USAF

 

[sferrin]

I don’t have the Mil power ratings of the -132 vs the -232, but I believe your bypass ratio comparison is correct.

I don’t know if the -232 would have had Vmax. The -220 was the same engine aerodynamically as the -100/-200, which had Vmax programmed into the EEC supervisory control, and this uptrimmed schedule was included in the -220 DEEC. The -229 could have easily incorporated it in its DEEC schedules, I assume the USAF decided there was not requirement for this capability.

Augmentor screech (high frequency combustion instability) and rumble (low frequency combustion instability) are often encountered during development, especially in the lower right corner where high ram pressures and AB fuel flows are encountered, with AB fuel flows running 2x sea level static conditions. It is common to limit AB fuel flow in the lower right corner to keep screech under control to prevent damage to engine hardware until tweeks to AB aero and fuel distribution tame the beast. Screech is difficult to predict and often requires iterative hardware / software changes and testing to arrive at a satisfactory solution.

Yes, the F100-232 would have had similar ratings and applications as the F110-132, which is currently only in the Block 60 F-16.

The -232 did have some additional development challenges. The new Fan was longer than the -229 fan due to the wide chord fan blade technology borrowed from the YF119 / F119 which made the engine longer at the front end. To keep the engine interface with the aircraft common with older F100s, the augmentor was to be shortened, the front of the gearbox extended, engine mounts shifted forward, and bleed air plumbing moved forward to line up with the existing aircraft facilities.

I remember a P&W ad back in the 90s that indicated they'd run a -232 at 37,150lbs of thrust as I recall. Do you know anything about that?

"Pratt & Whitney has completed initial altitude tests of an advanced version of the F100-229A flight engine, which is fitted with a new fan and inlet to boost power and increase durability.

The -229A is designed to power the Boeing F-15E and Lockheed Martin F-16C/D from 2000 onwards - either as a retrofit kit or as a complete engine - and has demonstrated a thrust capability of 165kN (37,150lb). The engine is in competition for US and export business with General Electric's similarly upgraded F110-129EFE (enhanced fighter engine)."

This was from an old issue of Flight Global but I'd seen a P&W advertisement on their website with that info as well.

 

[F119Doctor]

I remember a P&W ad back in the 90s that indicated they'd run a -232 at 37,150lbs of thrust as I recall. Do you know anything about that?

"Pratt & Whitney has completed initial altitude tests of an advanced version of the F100-229A flight engine, which is fitted with a new fan and inlet to boost power and increase durability.

The -229A is designed to power the Boeing F-15E and Lockheed Martin F-16C/D from 2000 onwards - either as a retrofit kit or as a complete engine - and has demonstrated a thrust capability of 165kN (37,150lb). The engine is in competition for US and export business with General Electric's similarly upgraded F110-129EFE (enhanced fighter engine)."

This was from an old issue of Flight Global but I'd seen a P&W advertisement on their website with that info as well.

Both P&W and GE ran their advanced fan engines up to the 36-37K thrust range as demonstration of the potential capability of the engines.

I suspect both of these demonstrations were run on a cold winter day, with inlet temperatures in the 30-40F range. With cold inlet air, the rotor speeds are less at full rated airflow, and turbine temperatures are much lower. This allows them to turn up the wick to push airflow and pressures to their maximum capacity without overspeeding or over temping the core to the point of immediate destruction. And even with these inlet temperatures, the turbine life at those demonstration temperatures would likely have been very limited. I believe both were quoting 4000 cycle turbine life at 32K, and extended life operated at the 29K level.

These days, current production configuration -229 and -129 engines are certified to 6000 cycle overhaul intervals, having incorporated the latest turbine cooling technologies.