Lockheed Martin F-35A, B, C and other ideas

[PR19_Kit]

The first friction welder I installed at R-R was just a technology tester and the samples were aboit 1" x 2" but soon after we put a big one in their Nottingham plant which was large enough to make the 2nd stage fan for the RB199 and later for the EJ200 engines. The original one was the size of a large 'fridge and the RB199 one was about the size of a Ford Fiesta.

The one they use for the F-35 engine is GINORMOUS, around the same size as my house, and the associated hydraulic power supply is around the same size! If they're using FW technology to make the Trent fans they must have an even bigger friction welder as the largest Trent fan is 8 ft in dia! However, they hadn't got that installed by the time I retired in 2008.

[jcf]

OK, are we talking specifically about the F-35 and its system, or lift-fan concepts in general?

If the latter, lift-fan concepts have been around for yonks, from flying platforms and the Omniplane
to the edge driven fans of the Avrocar and the Ryan XV-5A. The difference with the F-35 system is that it
is a true fan that is mechanically rather than jet efflux driven. The Bevilaqua patent was filed 5/90, and
granted 5/93.

Friction or Inertial welding has been used for decades. R-R's Linear Friction Welding process
was patented in 1994, and, according to R-R, was developed for the production of compressor
and turbine blade-disks (blisks) in general, not specifically for lift-fans. This capability is no doubt a
major reason that R-R were brought into the JSF project.

R-R LFW patent (filed 10/93, granted 11/94):
http://www.google.com/patents/US5366344.pdf

So it's a stretch to contend that Bevilaqua couldn't be the inventor of the F-35 lift system, as
his patent filing date precedes that of the R-R LFW by over three years, and your installation
of the first test welder by two years.

[PR19_Kit]

<sigh> 

The ORIGINAL bit of this thread concerned how the control system of the vertical lift part of F-35 works, and in the somewhat convoluted way of these things it got sidetracked by links that added more confusion rather than clarifying the issue.

Like I said at the end of my penultimate post 'It'd still be good to have a definative article on how the F-35 propulsion and control systems work, rather than PR items written by people who have their own axe to grind.'

[wuzak]

Some interesting display options with Red Arrows F-35Bs:

Mass vertical take-off
Mass "Bow" to the crowd
Two or more planes "hover-dancing" around each other
Opposed Pair fly along runway in opposite directions and stop dead nose-to-nose

The RN will be getting F-35Cs, not Bs. I doubt the RAF will go for the B either, preferring to go with the A, probably.

[wuzak]

The F-35 would probably need that much extra fuel to get anywhere, but that configuration destroys its stealth and thus is basically asking to be shot down.

[lenny100]

Some interesting display options with Red Arrows F-35Bs:

Mass vertical take-off
Mass "Bow" to the crowd
Two or more planes "hover-dancing" around each other
Opposed Pair fly along runway in opposite directions and stop dead nose-to-nose

The RN will be getting F-35Cs, not Bs. I doubt the RAF will go for the B either, preferring to go with the A, probably.

#
sorry but they changed their minds yet again and we might get the B after all

[PR19_Kit]

The RN will be getting F-35Cs, not Bs. I doubt the RAF will go for the B either, preferring to go with the A, probably.

Are you sure? The MoD have changed their minds on this a nymber of times, and if the FAA had the 'C' version they would need catapults and arrestor gear on the QRII class carriers and AFAIK that's not now the case as the ships will have ski jumps. In fact the MoD's own page says the Navy will be having the F-35B, 4th line down in the main text.

http://www.royalnavy.mod.uk/The-Fleet/Aircraft/Future-Aircraft/F35-JointStrikeFighter

The RAF's page on the MoD site doesn't mention the sub-type that will be ordered but if they DIDN'T have the 'B' there wouldn't be a hope of them operating from the carriers, as they did with the JFH's GR7/9s.

And I think that piccie of the F-35 with the big underwing and conformal tanks was posted 'tongue in cheek', this is the World of WHiff after all..............

[rickshaw]

Do you actually need the liftfan to use a ski-jump?  Other non-lift fan aircraft such as the the MiG-29 and the Su-27 manage it.  I admit it makes landing back on a carrier much easier but it isn't necessary.

[XV107]

The original plan was for the F-35B.

SDSR in late 2010  altered this for the F-35C for various reasons, including the fact that a CTOL carrier would permit interoperability with the USN and the Aeronavale.

That decision was reversed in May this year. Part of the rationale was that the cost of converting one of the carriers into a conventional carrier was prohibitive and that going back to STOVL would allow - funding permitting - both carriers to be employed in their designed role (rather than with one being the world's largest LPH or sold).

[PR19_Kit]

Do you actually need the liftfan to use a ski-jump?  Other non-lift fan aircraft such as the the MiG-29 and the Su-27 manage it.  I admit it makes landing back on a carrier much easier but it isn't necessary.

Maybe not, but it does increase the warload that you can lift.

Landing on with a ski-jump at the other end of the deck with no arrestor gear or hook could could concentrate the mind a tad, not to mention overeheat the brakes! And the F-35 has neither reverse thrust nor a tail chute AFAIK.....

As Mr. Farley said 'It's a lot easier to stop and land than it is to land and stop' 

[rickshaw]

Do you actually need the liftfan to use a ski-jump?  Other non-lift fan aircraft such as the the MiG-29 and the Su-27 manage it.  I admit it makes landing back on a carrier much easier but it isn't necessary.

Maybe not, but it does increase the warload that you can lift.

True.

Landing on with a ski-jump at the other end of the deck with no arrestor gear or hook could could concentrate the mind a tad, not to mention overeheat the brakes! And the F-35 has neither reverse thrust nor a tail chute AFAIK.....

As Mr. Farley said 'It's a lot easier to stop and land than it is to land and stop' 

Then add arrester gear.   Simples! 

[jcf]

"For the F-35B pilot, converting from conventional to STOVL mode will be no more complicated than pushing a STOVL conversion button. The same button on a conventional takeoff and landing F-35 (an F-35A or F-35C) lowers the tail hook. "The button initiates a magical transformation," says J.D. McFarlan, who leads the F-35 air vehicle development team.

This transformation, as McFarlan describes, includes the opening of all STOVL doors and the propulsion system preparing to engage the clutch. Once all doors are open, the clutch is engaged when sets of carbon plates are pressed together to spin the lift fan up from a complete stop to engine speed. Once the speeds between lift fan and engine are matched, a mechanical lock is engaged to remove the torque load from the clutch and permit operation to full lift fan power. After the lock engages, the propulsion system completes conversion to STOVL mode and responds to aircraft commands. The entire sequence takes approximately fifteen seconds.

When a pilot gets to a slow speed during STOVL mode, the sidestick is used to move the plane up or down. When the pilot's hands are removed from the controls, the airplane simply hovers in place.

"The conversion button sets a lot of things in motion," says Graham Tomlinson, a BAE Systems F-35 test pilot who participated in early test runs on the hover pit. "But the complexity is in the airplane and the propulsion system. Converting to STOVL, which is fully automated, is a smooth transition for the pilot." "

"The lift fan is covered from above by an aft-hinged door, which opens as the aircraft transitions to hover mode. Thrust is controlled by the speed of the lift fan, a set of variable inlet guide vanes that reside above the rotating blades of the lift fan, and by a device called a variable area vane box nozzle on the lower side of the fan. The vane box nozzle (middle photo) contains a set of six vanes (or louvers) that direct and control the amount of downward thrust emanating from the lift fan."

--from http://www.codeonemagazine.com/f35_article.html?item_id=13



VAVBN controllability:
"The thrust produced by the Rolls-Royce LiftFan exits
via a Variable Area Vane Box Nozzle (VAVBN). When the
VAVBN is active, it modulates the LiftFan thrust
between 41.75° and 105° of vector."

(extract from Vertiflite Vol.55, No.2)
--found on an RC site

[Alvis 3.14159]

Fine, we're out!
http://o.canada.com/2012/12/06/1107-col-dentandt/

Wait, we're in!
http://www.cbc.ca/news/canada/story/2012/12/06/poli-f35-pmo-government-fighter-jets.html

Arggggh! How can a guy make a Whif if they keep changing it???

Oh well, I'll try to concentrate on the least likely plane. Which would that be again, the Rafale, Gripen, Sukhoi, or Arrow?

Alvis Pi

[rickshaw]

Arrows always good...   

[wuzak]

The original plan was for the F-35B.

SDSR in late 2010  altered this for the F-35C for various reasons, including the fact that a CTOL carrier would permit interoperability with the USN and the Aeronavale.

That decision was reversed in May this year. Part of the rationale was that the cost of converting one of the carriers into a conventional carrier was prohibitive and that going back to STOVL would allow - funding permitting - both carriers to be employed in their designed role (rather than with one being the world's largest LPH or sold).

I stand corrected.

Thank you for the update.

What of the RAF? Are they opting for the -A, -B or -C?