LO,

Yes, I've seen the figures as well, still a bit of a sceptic on French claims - but I might be doing them a mis-service. They are considerable engineers, and I have never underestimated them. I just have a problem balancing the requirements I know JSF had to meet with the stated Rafale load penalty. Might be comparing apples and oranges.

The basic problem is that carrier ops generate loads and load paths that just don't exist in land based designs - you have to put new and extra metal in to cope with them. Nose gear launch loads are a good example. In some cases, you are dealing with quite terrifically large hunks of metal to get the loads around the airframe.

You're being a little hard on LM and the SWAT effort, if I might suggest. There is still a lot of commonality between the variants, it's worth remembering that all three were overweight, not just the B - they all had considerable redesign, and the solutions were, as far as practicable, common. However, you are quite right that some commonality had to be sacrificed. However, it's still a considerable achievement to get CTOL, CV and STOVL aircraft out of one basic configuration.

My guess is that the focus on F-35 will now move to the avionics. Firstly, because they have some big challenges to overcome in software and mission system testing. They'll beat them, but it will be a challenge. Secondly, the focus will shift as people realise just what avionics this aircraft is carrying as a standard fit, and the capabilities it is bringing. Interesting times.

Best Regards as ever to all those actually doing the business, whether in service or those working all hours to deliver the new kit

Engines

Interesting that LO claims above: "...Sean Stackley, the USN acquisition boss, warned the UK against switching back to the F-35B..."

Whereas this - I guess - is the article where there is no such warning from Stackley (only 'a defence source'):

"...“This letter could be a warning shot saying if you Brits go back to jump jet carriers then there might be no planes to fly off it,” said a defence source...."

Aircraft carrier costs will be half what you think, US tells ministers - Telegraph

Engines, the B is weight sensitve but when Burbage was in australia he said "The other two airplanes (f-35A &B) are not as sensitive to weight. We are actually probably several thousand pounds away from the first compromise of the performance requirements of those two airplanes"

LO, the acceleration doesn't sound too bad
"
““We’re dealing with the laws of physics. You have an airplane that’s a certain size, you have a wing that’s a certain size, you have an engine that’s a certain size, and that basically determines your acceleration characteristics,” Burbage said. “I think the biggest question is: are the acceleration characteristics of the airplane operationally suitable?”
The F-35 transonic acceleration specifications were written based on clean-configuration F-16 Fighting Falcon and F/A-18 Hornet fighter, Burbage said.

But unlike the Hornet or the F-16, the F-35 has the same configuration unloaded as it does loaded with weapons and fuel, Burbage said. When an F/A-18 or F-16 is encumbered with weapons, pylons and fuel tanks, those jets are robbed of much of their performance.
“What is different is that this airplane has accelerational characteristics with a combat load that no other airplane has, because we carry a combat load internally,” Burbage said, the F-22 Raptor notwithstanding.
Even fully loaded, the F-35’s performance doesn’t change from its unencumbered configuration, he said.
In the high subsonic range between Mach 0.6 to Mach 0.9 where the majority of air combat occurs, the F-35’s acceleration is better than almost anything flying."

I don't know if that is with degraded engine, like with other specs.
for what it's worth, it's said that the f-35A & C speed is 750 kn limited to m1.6 going by a chart sweetman posted so it's not slow either. FWIW a forum poster said that test pilot "Hog" Griffiths said the f-35A is supercuising at M 1.25

refer to my sentence again, "other assets will be called in as needed for the mission." now where is this non-defined hypothetical mission where the USN isn't going to send a carrier. I can't think where the USAF can't put awacs, can you?

On F-35 acceleration

"But even with the limited flight envelope released to Eglin for training, Spohn says that some of the F-35's characteristics are already apparent. The jet's subsonic acceleration is excellent.
"I think it compares very favourably to the F-15C," Spohn says. "I would say the acceleration in a straight line is absolutely comparable to the F-15C equipped with [Pratt & Whitney F100]-220 engines that aircraft is a pretty spy performer, if you will, and it compared very well with that."


Note that this was said by Maj Jay Spohn, chief of standards and evaluation at the 33rd FW's operations group.



(Though I imagine that a certain desktop warrior/ journalist will proclaim it to be nothing more than propaganda.)

As far as weight differences go between landbased and carrier based models, there can be many reasons why they differ so much sometimes, one of the most succesfull models ever, the F4 phantom even gained weight ,+400lbs between B and C models when it was adapted for the USAF comming from a NAVY carrier based model.

The Rafale numbers are most likely acurate considering how much they have in common , also it doesn't need stronger wings to compensate for a wing folding mechanism, and keeps the dimensions of the landbased Rafale.
EADS and SAAB are probably not far of the mark when they claim that a navalized version of their fighters (EF,Gripen) will only have marginal weightgain.

USNAVY 1962-F4B , 27,897lbs OEW
USAF 1962-F4C , 28,276lbs OEW

Engines,

Many thanks - and most interesting on the 25mm / 27mm calibre issue. My musings on USAF using Dave-C was simply how much would they be giving away to have a single variant - and how much would that save over the programme life?

I presume it is possible (ie, "only engineering") to USAFify a minimum change Dave-C (ie, add the gun and UAARSI), though this wouldn't deal with

However, if the choice were more Dave-C (mod-1 - Dave-D?) versus fewer Dave-A for the same money, it would interesting to see where the tradeoff is.

Kind regards, as ever.

S41

JSFFan - First, I already responded to your question about AWACS.

You'd have to ask Mr Burbage about the meaning of some of those statements. As for weight margin, we know that the A has packed on 2700 lb of OEW compared to predictions at contract award, while the C has snarfed down enough Big Macs to gain almost 5000 lb. "Several thousand more" sounds like there were some big margins in there.

For instance, the B-man may mean that they still meet KPPs, but there's a lot of daylight between "threshold" and "desired".

"The F-35 transonic acceleration specifications were written based on clean-configuration F-16 Fighting Falcon and F/A-18 Hornet fighter, Burbage said."

Well, which? One of these things is not like the other. Particularly an F/A-18C just before the -402 engine came in.

"it's said that the f-35A & C speed is 750 kn limited to m1.6 going by a chart sweetman posted".

There's limits and there's limits. An aircraft could run like a scalded jackrabbit to 1.6 and then hit a structural or heat boundary beyond which they just did not decide to test. Or it could have a nasty forebody and inlet design that creates wave drag and doesn't give you good pressure recovery, so that the jet hits a wall of treacle above 1.2 and it can just about scrape 1.6 with a low-hours engine on a cold day before the gas runs out.

"FWIW a forum poster said that test pilot "Hog" Griffiths said the f-35A is supercuising at M 1.25"

An SR-71 went to Mach 4.2. Says that on the intertubez.

ParlInfo - Parliamentary Joint Committee on Foreign Affairs, Defence and Trade : 20/03/2012 : Department of Defence annual report 2010-11
Mr Burbage: Weight is most critical on the short take-off, vertical-landing jet. That is the one that has the toughest requirement for taking off from and landing on small ships. You saw in the movie that we did that, this year. We predict the weight on that airplane to grow at about three per cent throughout the rest of the test program and it could grow some more throughout its life if more capability that has substantial weight goes on the airplane. (per year shoudn't have been said as it conflicts with facts)
If you look at the STOVL jet and you look at our weight charts, which you are more than welcome to see, we have now gone two years without any weight increase on the STOVL jet, and that is while accommodating engineering changes to the doors, which we have replaced with heavier doors, and other changes that were made to the airplane. (Dr JENSEN: I will show you the chart. I am afraid it is a bit small, but you can see there is January 2010 and there is January 2012. Clearly there has been a weight increase.
Mr Burbage: This increase right here is a ground rule change, not unlike other ground rule changes—when the weight of the electro-optical targeting system was added in, it is just a step function increase. If I bring this down and I measure that point directly back, it goes back two years to intercept that curve there.)
We manage the weight very tightly on that airplane—for good reasons, because it needs to be.
The other two airplanes are not as sensitive to weight. We are actually probably several thousand pounds away from the first compromise of the performance requirements of those two airplanes. We do, however, manage the weight very tightly on all three airplanes. The metric that we look at is when the weight growth curve levels off, that means your design has stabilised. You are no longer making lots of changes to the design. All three airplanes are now in that level-off phase. The best one is the STOVL where you can go back and see that we have not increased any weight at all in a full two years.
Senator FAWCETT: So having reached that steady state, you are saying you are some thousands of pounds away from—
Mr Burbage: On the non-STOVL jets.
Senator FAWCETT: So the conventional take-off and landing—
Mr Burbage: The key performance requirements that are weight-dependent have large margins still ahead of them. On the STOVL the key performance parameters are much tighter to the weight, because it is more physics than aerodynamics.
Mr Burbage: We have 16 key performance parameters on this airplane. Half are logistics and sustainment-related, half are aeroperformance-related and one or two are in classified areas. We have an oversight body called the Joint Requirements Oversight Council, the JROC, that looks at those requirements every year and makes decisions on them—'Are we going to meet them, are we not going to meet them? If we are not going to meet them, what is the impact of that?' We have one this year which was the range of the Air Force airplane which had a specific set of ground rules associated with how that range is calculated which is not similar to either of the other two airplanes. The airplane flies a large part of its mission at a non-optimised altitude in the original calculation. The JROC agreed to change the ground rules to fly that airplane as the other two were flown and, when that happened, the airplane had excess margin to the range requirement. For any performance-related requirements, we artificially penalise the engine by five per cent fuel flow and two per cent thrust. Those margins are given back as we mature the design and get more and more solid on exactly what it is going to do. They are there for conservative estimation up front. We have not taken back any of those margins yet so, when those margins are taken back, the airplane will continue to be well in excess of its basic requirement. The airplane is meeting all of the other requirements today.

Mr Burbage: To the original set. Today, all the KPPs are green because that ground rule was changed to be common across all three airplanes on the range. But we have not taken back the margins that are being withheld to make sure those performance predictions are conservative. We are not going to have degraded engines. We basically measure our performance characteristics with a highly-degraded engine capability. Our actual flight test information coming back from the engine is better than nominal. These calculations are not done using actual airplane test data. They are done using an artificial penalty that gets paid back as the design matures.


LO. think again what SL 750kn means with internal fuel and weapons and what other planes are, as to what you are saying. your mighty su.35 is 755kn clean

so a weight increase isn't a weight increase if it's a "a ground rule change"???

I hope that change includes more engine power because if not it'll be ground rule alright..................

It is an allowed known weight increase, as the hardware is installed to the path of the final weight.
With the eodas, it's now 32.353 and it's max final to be 32,719, although they want to get it about projected 32.577

refer quick look review page 48
http://s3.documentcloud.org/document...ern-report.pdf

I tried telling my wife that my needing a trouser with waist size 36" compared to 32" twenty years ago was a ground rule change. After all, consuming many steaks and bottles of wine is merely installation of additional hardware.

That went well.

I've a notion my overall power output might be a little down too.

as long as you don't have a premature missile fire, it's all good ;)


LO, Well we have the name of the test pilot, so no doubt some interested journalist will ask the question at an interview.

"I completely agree that you can only trust the people working directly on the program to get the most unfiltered answers.

I had the chance to chat with "Hog" (461st FTS F-35 test pilot) a couple weeks ago and I specifically asked his opinion on some of the controversial topics surrounding the aircraft including:

4th gen Comparison (specifically maneuverability): said he is dual qualified in both the 35 and 16 and while it doesn't perform as well as a clean block 50 Viper, when you factor in internal vs external ordinance and fuel the F-35 will perform better in combat (you guys already know this). They won't know exactly how it'll fair in a dogfight until OT&E begins later this year but he said that the F-35 will definitely be up to par with all 4th gen fighters.

Helmet mounted display/JHMCS: was very confident in the system and said they had almost all the bugs worked out. Gives him incredible situational awareness and he can even see threats below him. Eventually they will have the helmet set up so the "bitching betty" will talk into it based on where the threat is in relation to him (similar to a 5.1 surround sound system).

Supercruise: It takes afterburner to get past supersonic, but once there he can pull the power back to mil and it'll stay supersonic around Mach 1.25ish (you guys also know this, just reiterating).

Cost: very brief answer but said as the program continues to mature it will gradually decrease.

Datalink: Another very brief answer but his flight of 4 will know exactly what is going on around every flight member at all times. They can covertly share threat data between jets and they can even act as 2 independent 2-ship "hunter killer" groups (lead and 2 acting as shooters, 3 and 4 as controllers and even ECM).

IOC: Somewhere around 2017. Also said that individual squadrons will be able to deploy to a combat theater before the IOC date."

"until OT&E begins later this year"....

o rly?

BTW, the "interview" was popped on to f16.net by a pseudonymous newbie.

http://ic.pics.livejournal.com/babyd...5/original.png

"Cost: very brief answer but said as the program continues to mature it will gradually decrease."

I think a) he means the forecast unit cost b) this man is a real optimist.......

that's a funny definition...seeing that I made no claim and said the source was a forum poster, preempted by 'for what it's worth'
I said
"FWIW a forum poster said that test pilot "Hog" Griffiths said the f-35A is supercuising at M 1.25 "
"LO, Well we have the name of the test pilot, so no doubt some interested journalist will ask the question at an interview."

F-35 Mini Burner Cruising
 

F-35A Testing Moves Into High Speeds By DAVE MAJUMDAR : 13 June 2011

http://www.defensenews.com/story.php...72&c=FEA&s=CVS

"...The F-35's ability to carry weapons and a large fuel load inside its own skin makes the plane far less draggy on a combat mission than the F-16 or F/A-18, which sling missiles, bombs and fuel tanks below their wings and fuselage, Griffiths said . Moreover, a combat-laden F-16 loses much maneuverability, whereas the F-35 is barely affected by carrying 18,000 pounds of internal fuel and 5,000 of internal weaponry. "It flies fantastic," he said. Griffiths declined to compare the F-35 to the F-16s he once flew. But he noted the F-16 is only technically an 800-knot and Mach 2.02 aircraft. In practical terms, most pilots will never see speeds above 700 knots or Mach 1.6 because real-world load-outs don't allow it. The F-35 can't supercruise like the F-22 Raptor, but the test pilots have found that once they break the sound barrier, supersonic speeds are easy to sustain. "What we can do in our airplane is get above the Mach with afterburner, and once you get it going ... you can definitely pull the throttle back quite a bit and still maintain supersonic, so technically you're pretty much at very, very min[imum] afterburner while you're cruising," Griffiths said. "So it really does have very good acceleration capabilities up in the air." Retired Lt. Gen. David Deptula, formerly the Air Force intelligence chief and a veteran F-15 pilot, said having that kind of capability is a huge advantage. "I'm real happy to hear that in fact is the case, because speed gives you a variety of advantages," he said. "It allows you to employ your air-to-air missiles from a range much greater than otherwise would be the case."

Though the F-35's maximum speed is Mach 1.6, the F-35 test program will eventually push the jet a little beyond that limit to make sure operational pilots have a margin of safety, Griffiths said...."

Its worth nothing. The is Professional Pilots forum, many of the posters here are/were involved in the real world. You should respect that.

Linking to another forum as a reference is not acceptable on Wikipedia and its isn't on this forum or any other for that matter unless the source is verify-ably credible.

PW - The species trolliculus Australiensis is distinguished by its bellicose behavior and its ardent resistance to logic and the rules of argument.

Not to mention trolliculus Australiensis' natural and less developed enemy, querulous Vulgarus :hmm:

This is probably not a BFD but it is a PBD. Galrahn picks guest bloggers carefully, and he carries a remarkable amount of firepower in Navy circles.

Information Dissemination: Used Cars and F-35s