More delays for the F-35
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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?
Mechta,
And to think I was almost taking you seriously!
And to think I was almost taking you seriously!
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.
Last edited by Mechta; 17th Jan 2012 at 23:26.
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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.
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.
Originally Posted by GK121 posting as Bager1968
Of course, many have forgotten the problem the F/A-18A Hornet ran into during its initial carrier trials... specifically during the full-payload portion.
Simply put, the main landing gear had been designed incorrectly... when at or near max payload, with a centerline fuel drop tank mounted, every so often the landing gear would flex a bit too far during catapult launch, and the catapult shuttle would split the bottom of the fuel tank open!
Naturally, this was deemed undesirable, and carrier certification was halted until a fix was found.
It was determined that the entire main gear assembly, and possibly the center-fuselage section, would need to be redesigned... which was far too expensive.
The next-best fix was to lower the catapult tracks on all the carriers a few inches... and this is what was eventually done.
As this would only be done during a scheduled long maintenance period, modification of the carriers lagged behind replacement of the A-7s with Hornets... resulting in several carrier deployments with an extra A-6 squadron and extra aircraft in both F-14 squadrons and both A-6 squadrons.
This personally impacted me, as my USMC A-6E squadron [VMA(AW)-121] was assigned to CVW-2 aboard USS Ranger CV-61 from 11/85 to 8/89... during which time we made two 2-month deployments to Korea and two 6-month WestPac/IO cruises... and flew escort for tanker convoys through the Persian Gulf (late 1987).
Ranger had not been modified yet, so we had that "F-14/A-6 only" air wing. Ranger operated without any Hornets at all until her decommissioning in 1993 (2 years after the last USN A-7 squadrons transitioned to other types).
In that case, the carriers were modified because the aircraft fix would have been so expensive... and only the carriers needed to be modified (the land-based catapults at Pax River had been modified during the testing)... there were no land-based catapults elsewhere to be concerned about.
Simply put, the main landing gear had been designed incorrectly... when at or near max payload, with a centerline fuel drop tank mounted, every so often the landing gear would flex a bit too far during catapult launch, and the catapult shuttle would split the bottom of the fuel tank open!
Naturally, this was deemed undesirable, and carrier certification was halted until a fix was found.
It was determined that the entire main gear assembly, and possibly the center-fuselage section, would need to be redesigned... which was far too expensive.
The next-best fix was to lower the catapult tracks on all the carriers a few inches... and this is what was eventually done.
As this would only be done during a scheduled long maintenance period, modification of the carriers lagged behind replacement of the A-7s with Hornets... resulting in several carrier deployments with an extra A-6 squadron and extra aircraft in both F-14 squadrons and both A-6 squadrons.
This personally impacted me, as my USMC A-6E squadron [VMA(AW)-121] was assigned to CVW-2 aboard USS Ranger CV-61 from 11/85 to 8/89... during which time we made two 2-month deployments to Korea and two 6-month WestPac/IO cruises... and flew escort for tanker convoys through the Persian Gulf (late 1987).
Ranger had not been modified yet, so we had that "F-14/A-6 only" air wing. Ranger operated without any Hornets at all until her decommissioning in 1993 (2 years after the last USN A-7 squadrons transitioned to other types).
In that case, the carriers were modified because the aircraft fix would have been so expensive... and only the carriers needed to be modified (the land-based catapults at Pax River had been modified during the testing)... there were no land-based catapults elsewhere to be concerned about.
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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.
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.
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.
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.
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.
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Hunter hydraulics and breaks and tight circuits ......
Why would anyone do a run & break in a Hunter and select gear and flaps together during the first portion of the turn?
A real fighter pilot would not do that. He would pull hard in the break to kill speed, at the same time enjoying a looks good, feels good factor. As the 'g' comes off he would lower flaps, gear, flaps in quick succession. If the circuit is so tight that it is essentially a tight circle then utilities would be carefully selected as each speed limit was reached.
A real fighter pilot would not do that. He would pull hard in the break to kill speed, at the same time enjoying a looks good, feels good factor. As the 'g' comes off he would lower flaps, gear, flaps in quick succession. If the circuit is so tight that it is essentially a tight circle then utilities would be carefully selected as each speed limit was reached.
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
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 23ş flap on the break (actually, I preferred 38ş 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.
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 23ş flap on the break (actually, I preferred 38ş 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.
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
"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
Last edited by BEagle; 18th Jan 2012 at 20:45.
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. 
Anyway, we're agreed on the break.
Ooh. Good edit. Yep, I think you've got that right. Let me have a think.
Anyway, we're agreed on the break.
Ooh. Good edit. Yep, I think you've got that right. Let me have a think.
Last edited by Courtney Mil; 18th Jan 2012 at 20:49.
Well I guess it takes the laying on of hands, secret handshake and aprons of CFS...
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.....
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!
Still have my gismo thing. Mrs C just doesn't understand it!
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?
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?
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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.
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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....