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Old 20th Jun 2017, 02:13   #10521 (permalink)
 
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Luke AFB to Resume F-35 Flights After Hypoxia Investigation 19 Jun 2017 AP
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"GLENDALE, Ariz. (AP) — Luke Air Force Base will resume flights of F-35 fighter jets Wednesday after experts and engineers investigated a series of events in which pilots reported symptoms of oxygen deprivation. Officials with the 56th Fighter Wing at Luke said Monday that no specific root cause for the events was identified but specific concerns were eliminated as possible causes including maintenance and aircrew flight equipment procedures...." https://www.usnews.com/news/best-sta...-investigation
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Old 21st Jun 2017, 09:14   #10522 (permalink)
 
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Luke F-35s To Resume Flying, With Temporary Restrictions 20 Jun 2017 Lara Seligman
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"...The Air Force is not even sure the incidents are actually related to hypoxia, Canterbury stressed. The could be caused by hypocapnia— excess oxygen in the blood—or other physiological events that manifest similar symptoms...." Luke F-35s To Resume Flying, With Temporary Restrictions | Paris Air Show 2017 content from Aviation Week
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Old 21st Jun 2017, 12:33   #10523 (permalink)
 
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Old 21st Jun 2017, 13:49   #10524 (permalink)
 
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Spaz:
Thanks for the video link. A very informative briefing to understanding what they were doing. Comment: pedal turn? That's a helicopter thing, isn't it?
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Old 21st Jun 2017, 14:52   #10525 (permalink)
 
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I will stand to be corrected, but in a fighter it's a rolling maneuver at high alpha. It looks like a helo pedal turn when the flightpath vector is steeply downhill and airspeed is low, so the descent rate is hard to perceive.

The Su-35S display has a somewhat similar maneuver, but with more T/W to play with and better low-speed aerodynamics, the pilot can stop the turn and fly out. It seems that the F-35 has to stop, pitch down and dive to recover speed.
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Old 21st Jun 2017, 16:52   #10526 (permalink)
 
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I've seen the video and would like to see the 'B' do the same stuff, the amount of fuel needed for its STOVL performance would suggest its greater weight and greater demand for fuel for the lift fan and all are severe limiting factors. When SDSR 2010 recommended the 'C' and angled deck carriers the Government should have looked elsewhere than BAE systems and their profit margin to get carriers that would meet the requirement.

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Old 21st Jun 2017, 16:57   #10527 (permalink)
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Air Force gives House classified report on restarting F-22 program
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Old 21st Jun 2017, 18:18   #10528 (permalink)
 
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Finningley - The B is about 3000 pounds heavier than the A (OEW). Most of the difference is in the lift fan, so with no weapons and a light fuel load the B's CG will be quite a bit further forward than the A's (unless the A carries most of the fuel forward at part-load, which seems unlikely). Also, as part of the weight-saving exercise on 03-04, the B was given slightly smaller H-stabilizers. So it won't fly exactly the same way.

Last edited by George K Lee; 21st Jun 2017 at 18:47.
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Old 21st Jun 2017, 18:18   #10529 (permalink)
 
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Quote:
Originally Posted by Finningley Boy View Post
I've seen the video and would like to see the 'B' do the same stuff, the amount of fuel needed for its STOVL performance would suggest its greater weight and greater demand for fuel for the lift fan...
Why would STOVL have a greater demand for fuel???

I think a quick refresher on how jet engines work may be in order!

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Old 21st Jun 2017, 18:22   #10530 (permalink)
 
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ORAC, I for one hope that comes to pass. But as with all things modern, pricey, so what is the opportunity cost? What does DoD not procure to get the F-22?
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Old 21st Jun 2017, 20:39   #10531 (permalink)
 
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IF youse crabsters wanna pay for it a 5% boost in engine powered lift thrust for F-35B (& other things enginewise) notification.

Faster and Farther with Growth Option 1.0 19 Jun 2017 Pratt & Whitney

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Old 21st Jun 2017, 21:52   #10532 (permalink)
 
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Originally Posted by Just This Once... View Post
Why would STOVL have a greater demand for fuel???

I think a quick refresher on how jet engines work may be in order!

I'll bow to anyone's greater knowledge but I'd have thought that the necessity for a lift fan engine inside very much the same size airframe and the need to supply fuel to that lift fan engine from inside the same airframe would impose some sort of limit on weight and available internal fuel? Even without the use of fuel to the lift fan for 'STOVL' performance, in addition to fuel for the normal engine, I'd have thought the lift fan is surely just along for the ride? But again, I seriously would admit to not really knowing????

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Old 21st Jun 2017, 22:15   #10533 (permalink)
 
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Perhaps there is some word salad above about the F-35B LiftFan. There is ONE F135 engine in the F-35B requiring fuel. The LiftFan is driven by a shaft from that engine. Good explanation (amongst many others on the interrabble) here:

https://www.f35.com/in-depth/detail/...ks-f-35b-hover
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Old 21st Jun 2017, 22:32   #10534 (permalink)
 
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Some 'poxy bits' from Cobham may be helpful for F-35 'hypoxia-like' symptoms (me no like hypoxia).

US Air Force testing new sensors that could help solve F-35 pilot hypoxia puzzle 19 Jun 2017 Sebastian Sprenger
US Air Force testing new sensors that could help solve F-35 pilot hypoxia puzzle
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Old 22nd Jun 2017, 02:03   #10535 (permalink)
 
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Despite the F135 being the only engine which actually requires fuel, what's its fuel consumption like when driving the lift fan up to 20,000lbs of thrust continuously while trying to land on the deck of the carrier?

FB
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Old 22nd Jun 2017, 02:15   #10536 (permalink)
 
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I'm not a 'stop then land' STOVL pilot so most what 'I know' is from e-mails from ex-A4G gone STOVLies, articles & comments on fora such as this one. My overall impression is that a STOVL aircraft does not require more fuel in the landing phase particularly (no overhead bolter tanker required either) because of the certainty of landing vertically when in sight of that big flat deck. The STOVL Mode 4 flight can be relatively short depending on circumstances and it is guaranteed so no extra fuel is required in the landing pattern (unlike conventional carrier ops).

Yes the STOVL Mode 4 F-35B can burn fuel quickly as it is producing power approximately equivalent to being in afterburner however remember it is for a short time. I would like to be guaranteed a landing on a flat deck given enough fuel for that evolution. There is no 'trying to land' for the F-35B there is just 'STOP then LAND'.

BTW the F-35C appears to be a '3-wire machine' so far under test getting either 2 or 3 wire out of 150 attempts (discounting deliberate test bolters). It seems the F-35C will also stop 'trying to land' and as it says on the NIKE tin 'just do it'.

This particular thread must have a mine of information about 'stopping then landing' both for the Hairier & now the F-35B.
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Old 22nd Jun 2017, 03:05   #10537 (permalink)
 
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FB - Just to clarify things. I'm not sure that VL uses a lot more fuel than a conventional landing since the time in "V" mode is quite short. On the other hand, the V hardware is indeed along for the ride and is quite heavy. We know that the difference between A and B OEW is ~3000 lb, but the B also doesn't have an internal gun and is 7g rather than 9g.

The V hardware, particularly the fan, occupies space that would otherwise be available for gas and weapons. Internal fuel on the B is just about two-thirds of the A and the weapon bays are smaller.

JSF.mil > F-35 > Variants
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Old 22nd Jun 2017, 03:42   #10538 (permalink)
 
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Thanks Spaz and George, we're left with the same conclusion though, the 'B' is the runt of the litter, I can see how it was seen as a Harrier replacement in the Battlefield support role, exactly what the USMC require it for. However, it's now regarded as the replacement for the Tornado GR4, if we're getting 138, which I'll believe when I see, I think over 50% of them should be F-35As. Because apart from the party piece the 'B' is a poor relation to the 'A' and 'C'.

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Old 22nd Jun 2017, 04:10   #10539 (permalink)
 
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Then 'FB' you ignore any advantages the F-35B brings. Just today I read something... Perhaps naval aviation is new to you - especially STOVL ops as performed by USMC?
Quote:
"...The F-35B is also an important platform for the United Kingdom, which is a joint strike fighter program partner nation, said Rear Adm. Keith Blount, assistant chief of naval staff for aviation, amphibious capability and carriers for the Royal Navy.

The fighter will be flown off the nation’s new aircraft carriers, the HMS Queen Elizabeth and the HMS Prince of Wales, he said. The Queen Elizabeth could be deployed [wrong word here by reporter - she goes to sea for the first time] this month, with the Prince of Wales following in 18 months.

“We believe the QE to be a true fifth-gen carrier built from the keel up to accommodate fifth-gen fighter aircraft, and we’re very proud to say that the F-35B will be the aircraft of choice,” he said.

The STOVL variant is ideal for the types of missions the nation flies,
he added.

“The opportunities and potential of this airframe are almost endless. So we see ourselves right at the very forefront of jet aircraft and carrier strike capability by blending the Queen Elizabeth-class with the F-35,” he said." Marine Corps Wants F-35Bs Delivered Faster
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Old 22nd Jun 2017, 12:21   #10540 (permalink)
 
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With the greatest respect to Gen Davis and other senior Marine officers, their F-35B CONOPS is a very brave proposal.

My prediction is that if and when the UK does get more than the 48 F-35s that have budgets and delivery dates today, most of them will not be Bs - simply because there's no carrier space for 138 Bs, the RAF has no intention of re-inventing its Cold War Harrier operation, and if you have a runway the B is a much inferior aircraft to the A, while also being ~50 per cent more expensive.
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