Mechta,

And to think I was almost taking you seriously! ;)



So, I've been watching a number of vids of this wonder jet raising and lowering it's gear and I can't help wondering if this isn't another modern a/c with systems that aren't quite man enough for the job (no sexism intended and there are other manufacturers of a/c/ systems).:ok:

Thus, second generation fast jets were brick built **** houses with massive generators, engines that could eat birds and launch a man into space and hydraulic pumps that could power a JCB. Third gen FJs had Skoda generators, turbo charged 1.6 litre engines (when they really needed a 6 litre V8) operating closer to the surge margine than was always healthy and that struggled to pick up the gearbox load if it's mate quit and hyd pumps that were bought on ebay.

It's been a long night, but try to stay with me.

Now we're looking at an a/c that doesn't seem to want to operate all three gear legs at the same time - somewhat reminds me of the a/c my father flew where the gear legs struggled up one at a time.

Can someone please tell me this is because of some sound aerodynamic/stealth/technical reason and not because the utility hyd system just can't move all three legs at the same time?

Thats a great photo. Interesting how they already have reverse "leaf spring" type risers to keep the wire above the deck.

Hard to tell but isn't that the nose wheel? Wonder what it looks like when 2 spaced out main gears go over it?

Perhaps the 'Systems Operator' - the 'plane can pretty much fly itself - has to wind the gear up one leg at a time? The SO only has two hands after all, the other would be desperately podging buttons and flicking switches trying to get all the pretty lights in the workstation to stay green at the same time.

Courtney Mil, If you look in the box, and what you want isn't there...? :)

I agree with COCL2 that catching the wire before the mainwheels cross certainly has some merits. What the effects would be when the tyres do cross (hook losing the wire or tyres having cable dragged across tread) needs some investigation. If anyone can locate a photo like the excellent one that deskwizard found, but with the mainwheels crossing the wire, it would give us a much better idea with what the hook has to contend.

This 1/8th speed video shows the movement of a wire after the aircraft crosses it, although the hook caught one of the earlier wires. The main wheels cross within the first second, so be ready on the pause button:



One of the problems seems to be that the wire is dragged forward off the leafspring supports and is sitting on the deck at the time the F-35 tailhook would pass. More of the leafspring supports staggered 'upwind' of the first at half length separation and slightly to one side of the first, would keep the wire off the deck as it moves off the first set of supports, or just making the supports a lot longer (not taller) might do the job.

An interesting observation, Mechta... and something like you propose (for the cable supports) might well be added eventually.

I posted this on another thread, in response to comments about how incompetent LM had to be to screw up something as "simple" and well-known as catching the wire.

The last paragraph was in reference to comments made by others about the need to modify the emergency field arresting gear on all bases world-wide that a F-35C might divert to with an in-flight emergency.

Rather than the Goon & ELP bollocks interpretation here is an LM view:

Design blamed for F-35C tailhook issues
By Dave Majumdar - Staff writer | Jan 17, 2012

http://www.navytimes.com/news/2012/01/dn-design-blamed-for-f35c-tailhook-issues-011712/

"Lockheed Martin has traced the Navy F-35C Joint Strike Fighter’s troubles with catching a carrier’s arresting gear wires to the tailhook design.

Efforts to fix the problem are well underway, a top company official said.

"The good news is that it’s fairly straight forward and isolated to the hook itself," said Tom Burbage, Lockheed program manager for the F-35 program. "It doesn’t have secondary effects going into the rest of the airplane."

Moreover, the rest of the design of the tailhook system, which include the doors and bay that conceal the device and other ancillary hardware, is sound, Burbage said....

...The shape of the hook itself also has an effect on the probability of catching a wire, he added. All of these are being tweaked to increase the chances that the F-35C will catch a wire on a carrier’s deck.

"We’re doing a redesign of the hook to increase the probability the hook will engage the wire a high percentage of the time," Burbage said."

A lot more explanation at the URL jump above.

Not so in the Hunter! Select gear and flap together during the break with thrust at idle and it'd go into manual!

Rather than uprate the single hydraulic pump, the solution was to brief the pilots accordingly.

Good morning, BEags.

I was wondering about that when I wrote it last night. My doubt was what constituted a second generation jet. I wan't sure whether to call the Hunter and it's friends (MiG15, F-86, etc) first or second. IIRC, it was developed from the Sea Hawk, with its early protoype flying in the 40s. I guess it looks second gen and it was a replacement for the Meteor, so maybe amend my statement (which was rather broad anyway) to 'MOST' or 'A LOT' of second generation...

I was rambling anyway. Sorry.

I like Willard's answer best. Is that really true? Hand cranked, eh? I guess that saves on weight, system complexity and survivability, so good.

Hunter hydraulics and breaks and tight circuits ......
 

RB2,

You may have misunderstood BEags. In the break, select idle/idle, extend the speedbrake(s). At gear and flap limiting speed, lower gear and (half/mid/50%/etc) flap. In a lot of types those two limiting speeds were/are close enough together to have both services travelling at the same time and, therefore putting load on the relevant hyd system.

He didn't say "in the first portion of the turn". Gear and flap could certainly come DURING the break.

Courtney

Hi Courtney - yes, you have it. If I recall correctly from 36 years ago:

Approach at 420-450 KIAS (depending on whether there were any grown-ups in the tower) / 500 ft with power to idle as you cross the hedge (to make a nice blue note!). Then airbrake out and 23º flap on the break (actually, I preferred 38º flap as you slowed down quicker - remember that flap was originally used as the only airbrake in the Hunter), rolling and pitching as required to fit into the normal downwind spacing. Then at gear limiting speed, power up, airbrake in, PAUSE until the airbrake MI showed in, then gear down. Checks, then full flap starting the final turn and power to hold about VAT+10. Roll out at 300ft, let it come back to threshold speed, tweak on the control column and pop the drag bag as you touch.

..or drop the drag bag a little before you touched so that it fully deployed as the wheels hit the tarmac. Depending on who was watching!

With patter like that, were you a Q*I? Can't bring myself to say it. Probably not. You seem like a decent bloke.

'fraid so, Courtney, old chap! A2 on the Bulldog, VC10 and VC10K, civil FI and PPL/FE. All lapsed nowadays though.....

"L00kout, Attitude, Instruments!

And what about a FOEL check?"

;)

You mentioned 'second generation' jets earlier?

I reckon:

First generation: P-80, Meteor, Vampire, Sea Hawk
Second generation: F-86, F-100, Hunter, Swift, MiG-15
Third generation: Lightning, F-4, MiG-21/23/25
Fourth generation: F-14/15/16/18, Tornado F3, M2000. MiG-29, Su-27
Fifth generation: Typhoon, Rafale, F-22, Su-35

Standing by for corrections - that should open the floodgates to the little aluminium stepladder people :8

Well, my friend, someone has to be clever enough to do it. There may yet be some questions that I'll need answering, having spent my whole life trying to convince Q*Is that I knew what you were all talking about so that you'd pass my annual check ride. :ok:

Anyway, we're agreed on the break.:cool:

Ooh. Good edit. Yep, I think you've got that right. Let me have a think.

Well I guess it takes the laying on of hands, secret handshake and aprons of CFS...:ooh:

But weren't you a QWI? How I remember those clack, clack, clack, pause..."Hmm, ride up, early pickle, out of range" moments in the ciné rooms at Brawdy!

A mate was once asked whether he'd enjoyed some movie at the local fleapit as it hadn't had particularly good reviews. "It was great", he said, "first film I've seen in ages that doesn't suddenly stop before someone leaps out with a plotting jobber crying "You're out of range...you're out of range!".

Coolant on, tone as required.....:\

OK, fair cop. You have no idea how much fun I used to have with a young student in a dark room watching their home-made movies. At least it kept me off the beach at Saunton Sands!

Still have my gismo thing. Mrs C just doesn't understand it!

Typhoon, Rafale & SU-35 Gen 4.5 ;-)

This might need a whole new thread. Or perhaps just an unaswerable (?) question.

Spaz: "Rather than the Goon & ELP bollocks interpretation here is an LM view."

Can you explain, in the light of the current program situation, at what point LM's projections of how great things are going to look six months/a year from now have proven more accurate than their critics?

LO glad to get the thread back on topic. Which is what in your estimation? I had the F-35C hook issue in mind - specifically addressed in the link to the LM explanation about same. Also the QRL PDF report indicates the same intended fix. What the ELP/GOON scenario envisages is that this fix does not work and they go straight to DOOMSday. I'm patient enough to wait a few months to see if the F-35C hook 'intended fix(s)' work(s) [plural because there are at least two fixes in the works, hook profile and damper mechanism tweaking].

Spaz - As I think more qualified people have commented here, rolling or run-tests alone won't prove that the quick fix for the hook problem works. Engines does not appear to share your sunny optimism.

I'm patient to wait for testing of the fix mooted. People can speculate how they wish until tests show otherwise. After the land testing comes the carrier testing slated for 2013. In the meantime....

Spaz wrote ''I'm patient to wait for testing of the fix mooted. People can speculate how they wish until tests show otherwise. After the land testing comes the carrier testing slated for 2013. In the meantime....''

Spaz, thats fine, and entirely correct from a purely engineering point of view - but this isn't a purely engineering problem, its also a military asset problem where time (and at this stage, credibility) is the crux issue. saying 'oh, we'll find out in 2013 if its going to be problem that requires a complete redesign of the rear half of the aircraft' isn't much use when we're a mere 20 days into 2012, and the current delay in the system, let alone the delay forced by having to completely redesign the bugger, means that these aircraft won't be available to protect UK national interests - which, lets remember, is their one and only function and raison d'etre - until 2020 at least.

i remember when JSF was going to be a fielded force by 2012 , could be maintained at a rough field location by three men, and would cost $60m apiece. i'm afraid that at this stage 'oh, we'll find out next year if we have to redesign the aircraft' isn't the correct answer.

An interesting view 'cokecan' but I have no sympathy nor will the USMC for your F-35C potential problems. Youse can always revert to the F-35B and use EMALS & AAG on your new CVF flat decks to launch / recover UAVs or EW aircraft. All that remains to be seen. If you read the LM's Burbage blurb you will note that the hook is going to be tested soon. Even if there were no current F-35C hook problems there will be no actual carrier testing until 2013 in any event.

http://www.navytimes.com/news/2012/01/dn-design-blamed-for-f35c-tailhook-issues-011712/

"...Tests with the newly modified tailhook should start at Lakehurst, N.J, in the second quarter of this year [2012], Burbage said.

That will give the F-35 program another set of data to study to make sure the new design works as promised. However, until those tests are done, there is no ironclad guarantee that the redesign of the tailhook will work, but Burbage said he is confident of that the modified design will be successful.

"The big test for this airplane is not until the summer of ’13 when we take the Navy jet out to the big deck carrier and do actual traps at sea," Burbage said...."

Hmmmm. Reading between the lines, they can't meet a key contractual requirement, and are trying to persuade the customer it's not important. Good luck with that...... :ouch:

F-35 May Miss Acceleration Goal

The F-35 Lightning II’s transonic acceleration may not meet the requirements originally set forth for the program, a top Lockheed Martin official said.

“Based on the original spec, all three of the airplanes are challenged by that spec,” said Tom Burbage, Lockheed’s program manager for the F-35. “The cross-sectional area of the airplane with the internal weapons bays is quite a bit bigger than the airplanes we’re replacing.”

The sharp rise in wave drag at speeds between Mach 0.8 and Mach 1.2 is one of the most challenging areas for engineers to conquer. And the F-35’s relatively large cross-sectional area means, that as a simple matter of physics, the jet can’t quite match its predecessors.

“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?”

A recent report by the Defense Department’s top tester, J. Michael Gilmore, says that the Navy’s F-35C model aircraft, which has larger wing and tail surfaces, is not meeting requirements for acceleration. The report doesn’t say whether the F-35A and F-35B have hit similar snags.

Richard Aboulafia, an analyst with the Teal Group, Fairfax, Va., said that the revelation was not particularly surprising. “It’s a strike fighter,” Aboulafia said. “It’s not an interceptor; it’s not an F-22.” Aboulafia said it was unclear whether additional engine power could boost acceleration in the difficult transonic regime. So far, doubts about the aircraft’s aerodynamic performance haven’t diminished Lockheed’s sales prospects, he said.

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.

Thus far, Lockheed has not had issues with the plane’s acceleration, Burbage said. There are top level Key Performance Parameters from which lower level detailed engineering specification are derived and Lockheed’s job is to meet as many of those specifications as possible within the laws of physics, he said.

Discussions are underway about if those original specifications are relevant given the jet’s acceleration in a combat configuration, Burbage added......

I don't know about telescopic hooks, but the Bucc had a spring at the top of theirs, which, I presume, was to mitigate the initial shock of the arrest. Which, I suppose, made them "telescopish"

"Hook-skip" isn't a wholly new problem. The Gannet used to suffer from it a bit, especially in HMS Hermes which had rather more camber to the deck in the region of the wires than other carriers, so the wire touched the deck even with the bowsprings up. It wasn't a major problem - you just bolted. But it helped if you didn't pull the power back to 'ground idle' as you touched...

Does anyone know the proportion of hook-skips that can be expected with the F35? Every time, sometimes, or once in a blue moon?

Are you suggesting that we should give the contract to a womanufacturer?;)

Sharp, my friend. Very sharp! :)

“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.

AFAIK none of these factors, even including the laws of physics, has changed since 2001. So in view of the amazing modelling and simulation technology deployed in the program, one wonders how long they have known that the KPP was at risk.

By the way, there was a chap named Burbage at LockMart a few years ago, who seemed really confident that the program was going swimmingly and was "on track to meet the revised budget, timetable and performance goals set more than two years ago."

At Home And Abroad, Criticism Of F-35 Persists

I wonder if he's any relation?

Spaz - You are missing the most likely reason that the Brits went to the F-35C in the first place, which was that the B was having problems and was (in late 2010) about to be put on a two-year probation. The result was that the UK would go into 2013 with two irrevocably STOVL carriers and potentially no jet. By going CATOBAR they knew that they would always have an option, because the US Navy will always have jets.

My guess is that before the B-to-C switch was announced, the UK went to the US and basically said "Can you guarantee unequivocally that the B will go into service?" and that the answer was "well, er. that's the program of record, but..."

For once we agree LowObservable. We can only guess about the future.

Despite the turnaround by UK from F-35B to F-35C more options for using either variation on CVF is presented to youse as explained.

The 'turnaround' from B to C only works if we can remodel the carrier to do cat and trap. I hadn't realised what a massive rebuild that will be. It's not a scab-on or minor mod, to put it mildly. I shall invite an well-informed naval chap to explain here what he has explained to me.

Standby...

Seanethebrave..."To me, the B looks like it's a dead man anyway... and the recent slew of bad news being leaked, makes me think that delays are imminent (USAF/USN IOC 2020?)."

From recent news.....The Marine Corps on Wednesday took delivery of its first two F-35B strike fighter production aircraft. BF-6 and BF-8 arrived at Eglin AFB, Florida, from Lockheed's F-35 assembly plant in Fort Worth, Texas. They are now assigned to the 33rd Fighter Wing that runs Eglin's joint F-35 schoolhouse.

Thought the info might be of interest.

Daz

Courtney Mil, I'm pleased you have been appraised.

Apprised, maybe.

Rivetting. Awaiting correction.

Not a correction, Spaz, really. Nothing to correct as far as I'm concerned. Just some detail I was given that may be of use. I'll dig it out.

Daz,

I did see that a few days ago... I get the feeling that it's only the concurrency regime that has prompted this though, not the aircraft excelling itself through the test programme. Aren't all the US service jets firmly tethered to the ground at the moment for some sort of safety reason?

Good news for the F-35B
 

Lockheed’s F-35B Said to Be Getting Panetta’s Backing - Businessweek

Probation should be over so we can move on and concentrate on other issues.:D

so we should buy the -B and not the -C?
At present the -C looks the bigger risk.

Either that, or the Commandant pointed out that it was hardly fair to single out the B given the problems with the C...