Latest F-35 AA-1 test flight photos (Flight 24 thru 26)

[LinkF16SimDude]

Photog may have snapped it when the latches were in transition and hadn't sucked the thing down completely (or as it was just released)(?). The in-flight close up looks like it's a pretty seamless blend.

[That_Engine_Guy]

Personally, I doubt thrust would be a problem! First, because a bomber version would not require the thrust to weight ratio of a fighter. Second, the GE F-136 is suppose to make much more power than its P & W cousin. Either way power or lack thereof shouldn't be a issue.........Note: The proposed FB-35 would likely have a larger wing with more lift!

I would agree on the first and third points
1 an FB variant would not need a high thrust/weight ratio
2 an FB variant would have a larger wing for a heavier load.

But as I mentioned in another thread.

According to "Jane's" here are some given performance ratings

GE F136
40,490lb MAX
26,090lb MIL

PW F135
43,000lb MAX
28,000lb MAX

GE's site for the F136 says "Thrust Range: 40,000 lbs."
PW's site for the F135 says "Thrust: 40,000 lb"

Like the PW-229 and the GE-129 they are probably VERY close; IE "29,000 lb Class"

Since..

"The F136,is being designed to be installationally interchangeable with the F135, and also to respond in precisely the same way to all interfaces between engine and pilot so that in theory a future F-35 pilot would not know which type of engine was installed in his aircraft."

I doubt there would be a BIG difference in thrust or the pilot may notice?

Look at the historical improvements to the PW F100 and GE F110 as an example....

The F100-PW-100 started out at about 24,000 lbs of thrust at MAX and about 15,000lbs at MIL. The PW-229 grew to 29,000 and 18,000 respectively, which accounts for a 19% increase at MAX and 24% improvement at MIL.

The original F110-GE-100 made about 28,000 and 16,500 respectively but only increased power a bit with the GE-129 to 29,000 and 17,000. About 4% at MAX and 3% at MIL.

In the PW-232 and GE-132 both engines could reach 32,000 at MAX but clearly PW had a greater "thrust growth" over the life of the F100 design. Both engines were said to be capable of about 37,000 MAX if used with an "ideal" inlet.

Either company can push power up in their engine design. As technologies mature and develop over the years they are included in new and modified parts. As engines mature they will tend to increase overall performance through increased durability, economy, weight savings, or power. (In any combination)

PW isn't going to fall for the same trick they did the last time. "Build us an engine of about 25,000lbs MAX to these specifications based off your previous design so we save money, but then we're going to throw money at your competitor to enter their design years later based off a totally new design not constrained by previous factors. Oh and after your engine has been in use for 10 years allowing us to figure out exactly what we didn't like, we'll tell your competitor that information too so they can be sure their initial design doesn't seem like more of the same. This is the size of the inlet too, so build your engine to use only this much air... You can't have any more because the design of the airframe is final, but..."

I'd think they've learned their lesson and the F135 will posses plenty of growth margin so they'll be able to crank up the power in later "dash models" and compete with the perceived "newer" F136 of GE.

[Corsair1963]

Personally, this is the first time I've heard of the GE F-136 making less than the P & W F-135! As a matter of fact many sources claim high 40's and I have even seen 50's. Yet, that is just off the web. So, I have no hard facts and most sources would have to be considered suspect at best. So, I guess I will have to yield to your greater knowledge. That is until something more official comes along.........That said, is a F-100/F-110 really a fair comparison to the F135/F-136???? As the former two are much closer in design than the latter two.

[That_Engine_Guy]

I was just illustrating the point if the GE F136 hits the street with say 4K more thrust, that the PW F135 may have a little more to give to even things up again. Much like the increases in the F100 to even things up.

Lets not forget the F100/F110 were not "installationally interchangeable" as the JSF (F-35) program has required. Even if the engines' basic designs are totally different they still have to fit the same hole, with the SAME intake, and same interfaces, etc so that they are truly interchangeable.

[checksixx]

GE's have traditionally drank a lot more gass also...there is a trade-off. That very fact ran one F-16 driver out of fuel after the ANG unit started receiving GE powered vipers.

[dwightlooi]

Well...

(1) P&W has published 43,000 lbs / 28,000 lbs in a press release document.
(2) GE has not published anything.
(3) The only documentation of the F136 that making significantly more thrust came from the proposed version for the X-32 with 52,000 lbs in reheat. This may or may not be of the same diameter as the currently firmed up F-35 engine envelope which can no longer be changed to suit an engine.
(4) Having said that, if the F136 is based on the F120, it may have a LARGER core than the F135 which is based on the F119. This is because the F120 -- aside from the variable bypass feature (which won't be on the F136) also has a BIGGER core than the F119. This being the case MAY mean that it has a higher thrust potential -- especially in dry thrust. It MAY also mean that given a constrained maximum diameter, it may have a lower bypass.

[Lightndattic]

Guys, lets not forget that the F110 wasn't a clean sheet design 10 years after the F100 came out. It was developed from an engine that was already making 30,000+ pounds of thrust, the F101.

The F-119 and F-120 were closely matched during the ATF competition. It would seem their offspring would be similarly performers.

[SnakeHandler]

Back to the canopy bow for a second. It is a problem for me just because it increases my vis lookout workload unless the synthetic vision system works as advertized. Just saying that it could be an issue and I'd personally take the added weight of the clear canopy to be guaranteed a clear view. One reporter's opinion.

[That_Engine_Guy]

Guys, lets not forget that the F110 wasn't a clean sheet design 10 years after the F100 came out. It was developed from an engine that was already making 30,000+ pounds of thrust, the F101.

The F-119 and F-120 were closely matched during the ATF competition. It would seem their offspring would be similarly performers.

The F110 wasn't a "clean sheet" design, I will agree with that, but it was tailor designed/fit to compete directly with the F100. The F100 that was chosen to power the F-16 due to being used in the F-15. It was done to keep down costs of the "cheap" fighter down by limiting engine development costs.

PW didn't have the luxury that GE had being the "alternate engine". PW was given a design specification that the F100-PW-200 had to meet. Intake performance, thrust requirements, etc, etc. Ten years later GE was only required to fit in the same hole as the PW. Almost none of the interfaces are the same, nor are engine limits, or support equipment and the basic airframe was even modified so that the GE would develop the promised thrust increase.

I'm glad to see that the JSF/F-35 program is working to keep both engines truly interchangeable. I still have my doubts of any force having mixed types, as it doubles maintenance/logistics/deployment costs over the life of the entire program.

[Lightndattic]

Back to the canopy bow for a second. It is a problem for me just because it increases my vis lookout workload unless the synthetic vision system works as advertized. Just saying that it could be an issue and I'd personally take the added weight of the clear canopy to be guaranteed a clear view. One reporter's opinion.

The STOVL version and the desire for commonality kills the thick, one piece canopy. It's so much quicker to go through the canopy, than to wait for it to clear. That's a few seconds that might make all the difference for a B Model pilot who's having a bad day.

[LMAggie]

Back to the canopy bow for a second. It is a problem for me just because it increases my vis lookout workload unless the synthetic vision system works as advertized. Just saying that it could be an issue and I'd personally take the added weight of the clear canopy to be guaranteed a clear view. One reporter's opinion.

I'm no fighter pilot, but I assume most would rather have performance. And, as another poster pointed out, this may be a moot point because the new HMD may eliminate the bow. But that is just speculation right now.

[SnakeHandler]

Let's hope for the best.

[sferrin]

Well...

(1) P&W has published 43,000 lbs / 28,000 lbs in a press release document.
(2) GE has not published anything.
(3) The only documentation of the F136 that making significantly more thrust came from the proposed version for the X-32 with 52,000 lbs in reheat. This may or may not be of the same diameter as the currently firmed up F-35 engine envelope which can no longer be changed to suit an engine.

Sounds like you've got that mixed up with the F135 that was in the X-32 which in fact did reach 52,000lbs in full after burner.

[checksixx]

Wasn't that a static sea-level test uninstalled in the aircraft?

[That_Engine_Guy]

Yes the test engine for both the X-32 and X-35 were PW F119 prototypes using the name "JSF119-". Any facts, figures or feats from the fly-off were solely PW. Don't believe me? look at the photos of all the JSF prototypes and see that beautiful PW Eagle logo.

Formal release of the final RFP for JSF was expected on 7 March 1996, but was delayed to June 1996, with contract award date in November 1996. X-32 and X-35 designations allocated to demonstration phase which was planned to conclude in February 2001, although it now appears likely to continue until mid-year; successful teams will each build two aircraft, with CTOL version to fly first. STOVL versions to fly second and participate in assessment and demonstration of hover and transition qualities.

Three candidates were in contention for weapons system concept demonstration (WSCD), originating from Boeing, Lockheed Martin and McDonnell Do uglas/British Aerospace/Northrop Grumman.

All three contenders chose Pratt & Whitney's F119 engine for their WSCD proposals, although a General Electric/Allison/Rolls-Royce team secured a US$7 million contract in March 1996 to examine alternative power plants. These were based on the General Electric F110 and YF120 engines, with the latter being chosen in May 1996 following Congressional directive aimed at fostering competition and also overcoming possible impact of developmental or operational problems with the F119. Further US$96 million multiyear contract awarded in February 1997 to cover technology maturation and core engine development of YF120-FX version over four year period; this likely to result in follow-on development programme starting in 2001, culminating in full-scale EMD from 2004. If necessary, it is planned that the F120 engine will be available from the 72nd production aircraft onwards.

Remember the X-32B had a direct lift system. (No LiftFan) All the propulsive effort was from the main engine. The F-35B figures often combine LiftFan, Roll duct, and Main Engine thrust for a combined total. This may be why the X-32 cited a higher thrust than the X-35?

Another thing to remember is the JSF119 engines in both JSF candidates were prototypes. Prototype engines often do not have the reliability or maintainability of a production engine. That said, it may have produced 52,000lbs of thrust at MAX but how long would that engine have lasted? 4000 cycles? 2000 cycles? less? After making the engine production ready, some performance/features may be lost or gained.

Perfect example is the F100-PW-232 (not produced) that was "tested" up to 37,000 of thrust on a test-stand. At that rate it would have barely made 4000 cycles in my opinion. When it was ran at "-229 thrust levels" it was said to double the cycle life of the PW-229, lowering the overall cost of ownership. Tuned to 32,000 as offered for the F-16 Block 62 (to compete with the GE-132) the engine would have had greater life than a PW-229 but with more thrust, but not quiet twice the life expectancy.

Back to the GE F136, it hasn't even flown yet...

...The F136 engine is a 40,000+ lb. thrust, combat engine that will be available to power all variants of the F-35 for the US military and eight partner nations... ...The first full System Development and Demonstration (SDD) engine is scheduled to begin testing by early 2009, with first flight in the F-35 to follow in 2010.... ...The SDD phase is scheduled to run through 2013; the first production F136 engines are scheduled to be delivered in 2012 for the F-35 Lightning II aircraft....

Posted TODAY at GE: http://www.geae.com/aboutgeae/presscent ... 80320.html

Keep 'em flyin'
TEG