Third F-35C Flies

Discuss photos, special paintschemes and serial numbers of the F-35
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sprstdlyscottsmn

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Unread post24 May 2011, 20:10

And tidbits like that are why you are such a valuable asset to the forums.
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johnwill

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Unread post25 May 2011, 00:43

Thanks for your kind words.
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Unread post25 May 2011, 15:39

So back to the actual F-35C. That front view of the approach makes one thing sparklingly clear, it has a HUGE wing. Should have quite the favorable approach speed. I know that using wing loading as a metric can be flawed, but comparing F-35A to F-35C it shouldn't be too far off. The F-35C has 77% of the wing loading of the F-35A at gross internal weight. Not bad for a fuel fraction of 33% and a weapon fraction of 9%. The Super Hornet would need three external tanks to reach that ff, ick.
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neptune

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Unread post26 May 2011, 22:47

codeonemagazine wrote:Afterburner shot from today...


Does the F-35 have flaperons?

Obviously they are pitched down for lift on takeoff but wouldn't the computer continue the pitch control in thin air until it detected roll movement from the aileron on into the flap? Slow speed, high altitude, thin air.

And the elevators, are they independent and would they pitch (reverse; one up and one down) in a roll control?

On the J-20, the tails (rudders) are independent; for controlling drag or another flight condition?

Wow! lots of questions from one "Good" photo?
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Unread post26 May 2011, 23:31

Apparently the F-35C has ailerons & flaps - not sure if the flaps flap as flaperons?

Despite Setbacks, JSF Achieves Milestones by: Chuck Oldham (Editor) on November 22, 2010

http://www.defensemedianetwork.com/stor ... ilestones/

"...While the F-35A and F-35B can be mistaken for each other in some flight modes due to their identical wingspan and flight surfaces, the F-35C shows some clear differences. The wing area is 35 percent larger, at 668 square feet, against 460 square feet for the F-35A and B. Likewise wingspan is 43 feet for the F-35C, in comparison with 35 feet for the other two variants. The bigger wing of the F-35C employs inboard flaps [NOT flaperons] and outboard ailerons, beginning at the wing fold, for better control and slower approach speeds in the carrier landing environment, the other two variants using full span flaperons. Likewise, the horizontal and vertical tail surfaces are noticeably larger. One result of the increased wing area is an overlap (when seen from above) between the mainplane and the horizontal tail not seen in the other variants, to the extent that the inboard flaps on the F-35C have a cutout near the fuselage at the same angle as the trailing edge of the tail surfaces, presumably to preserve edge alignment.

Beefier landing gear to stand the shock of carrier landings, including a twin-wheel nose gear with catapult bar, and a more robust tailhook assembly are also noticeable, although a heavier internal structure is largely hidden by the skin.

The larger wing area carries a bonus of increased fuel tankage (around 19,750 pounds) and therefore longer range than the other two variants. How much the increased wing area will affect transonic performance remains to be seen, but it has to be said that the F-35C looks right...."
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JSF wing spreads by Bill Sweetman at July/5/2007

http://www.aviationweek.com/aw/blogs/de ... e0b200c7de

"...The F-35C is unusual among modern carrier aircraft in having a simple high-lift system, comprising part-span flaps and drooped ailerons. The Super Hornet, about equal in weight, has a smaller wing fitted with massive trailing-edge flaps that extend across the entire span. The inner sections actually extend rearwards as well as downwards, to increase the wing area.

Why doesn't the F-35C have a similar system? Part of the answer is geometry - the close-coupled tail may not have the leverage to overcome the trim change of bigger flaps. A more complex system would also reduce commonality with the other variants."
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I wonder what is happening with the SPOILER? for the F-35C.

Lockheed Martin develops wing spoiler for F-35C flight test By Rob Coppinger DATE:May?/08/09 :Flight International

http://www.flightglobal.com/articles/20 ... for-f-35c- flight.html

“Lockheed Martin is developing a spoiler for F-35C Joint Strike Fighter flight test aircraft to counter potential wing drop in transonic turns.

Wing drop in high rate transonic turns is a problem because it results in a turn becoming a roll.

Because leading and trailing edge flaps may not be enough to counter this phenomenon, the carrier variant F-35C will have a 4.5kg (10lb) spoiler added to the centre of its outboard wing for the test programme.

The issue of transonic turn wing drop was a lesson learnt from the Boeing F/A-18E/F Super Hornet programme.

The same issue has been studied in wind tunnels for the F-35 programme.

Despite the addition of this control surface Lockheed does not expect a radar cross section signature impact.

At the American Institute of Aeronautics and Astronautics' 45th Joint Propulsion Conference in Denver Colorado Lockheed Martin's F-35 development vice president JD McFarlan III told Flight International, "[the spoiler] has been designed to be LO compliant."

In other developments for the programme, the first short take-off and vertical landing variant's flight test is planned for September at Naval Air Station Patuxent River. Pratt and Whitney is to deliver five production F135 engines later this year and has delivered 12 of its contracted 18 test engines, five of which are for STOVL flight.

The General Electric/Rolls-Royce F136 engine will have maximum afterburner tests later this month and the engine's three variants have now achieved more than 800h of test time.

While the F135 engine has achieved over 12,000h of 14,250h planned test hours, over 5,750h of which are for the conventional variant and another 2,300h-plus for the STOVL.

McFarlan added that the F-35's inlets have been designed for 10% engine thrust growth and that higher temperature fuels were of interest to enable the fighter's fuel to become a better heat sink.
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Unread post27 May 2011, 01:58

These chaps say F-35C has FLAPERONS & AILERONS:

http://www.aerospaceweb.org/aircraft/fighter/f35/
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http://airfighters.blogspot.com/2007/06 ... ng-ii.html

"The US Navy needs much the same capabilites in its F-35C carrier variant (CV) model based on the X-35C. This model is intended to complement the F-18E/F and give the Navy its first dedicated stealth attack aircraft. However, the F-35 CV is modified to meet more stringent range and landing requirements. The most obvious of these modifications is a 35% larger wing permitting a higher fuel capacity and providing greater wing area for improved lift at low speeds. Other changes to the F-35 CV version include larger fin and elevator surfaces, ailerons in addition to flaperons on the wing, enlarged control surfaces, a modified control system, strengthened landing gear, a catapult launch bar on the twin-wheel nose gear, an arrester hook, and a wing folding mechanism."
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johnwill

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Unread post27 May 2011, 03:23

Looking at the F-35C photos in the Code One gallery, it is clear that inboard and outboard trailing edge control surfaces act as flaperons. Call them anything you want, but they are flaperons.

It is also clear that horizontal tails are used for both pitch and roll control.

The conventional use of inboard and outboard flaperons for roll control is to use both surfaces at low airspeeds and gradually wash out the use of the outboard surface as speeds go higher and higher. At high speeds, the outboard surfaces will twist the wing the opposite direction and cause loss of roll effectiveness, so roll commands to the outboard surface are reduced. The F-35C may or may not use this scheme. Furthermore, roll commands to the horizontal tail are usually increased as speeds increase.
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lamoey

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Unread post27 May 2011, 04:03

Is it possible that they are using some form of wing warping like NASA tested on an F/A-18?
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Unread post27 May 2011, 04:21

johnwill, thanks. I reckon that the flaperons on the other two F-35A & B are replicated on the F-35C also from other 'not definitive' text read recently online. Seems reporters don't really understand and do not explain or clarify. One manufacturer which makes some gubbins for these tihings seems to suggest all three have flaperons. There is a good photo of the F-22 getting its control surfaces all atwist. I'll post it here. Now same photo is attached oriented so that the controls being BENT are more obvious. :roll:

http://www.airliners.net/photo/USA---Ai ... 1534961/L/

http://cdn-www.airliners.net/aviation-p ... 534961.jpg

Image
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http://www.codeonemagazine.com/images/m ... 7_4142.JPG

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F-22controlsBENT.jpg
Last edited by spazsinbad on 27 May 2011, 04:49, edited 2 times in total.
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Unread post27 May 2011, 04:44

lamoey wrote:Is it possible that they are using some form of wing warping like NASA tested on an F/A-18?


Of course, it's possible, but almost certainly they aren't. That would imply a very flexible outer wing, and that would lead to flutter problems.

Orville and Wilbur were the first to use wing warping for roll control in powered flight.

Added comment about F-22 photo:

Interesting photo. Did you notice the wing surfaces are trying to roll the airplane to the right, while the horizontal tails are trying to roll it to the left. Seems rather odd, but it can happen. In an abrupt change of roll command, like terminating a right roll with an abrupt left command, the tails and wing surfaces may move at a different rate, so the briefly the surfaces may be deflected in opposite directions. I would like to see the video of that maneuver to see what is really happening.
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Unread post27 May 2011, 07:08

johnwill wrote:Looking at the F-35C photos in the Code One gallery, it is clear that inboard and outboard trailing edge control surfaces act as flaperons. Call them anything you want, but they are flaperons.
It is also clear that horizontal tails are used for both pitch and roll control.
The conventional use of inboard and outboard flaperons for roll control is to....

Seems like this question has already been answered, but....

The F-35C is the same as F-22: two pairs of wing trailing-edge devices - inboard (flaps, flaperons, whatever) and outboard (ailerons). Each pair has its own symetric schedule, based on flight condition and mode. Additionally, both pairs are used asymetrically for roll control. The horizontal tails are also commanded asymetric for roll, in addition to their use for pitch control (symetric, obviously). As john described, the relative allocation between the three different pairs for roll control is highly scheduled with flight condition, based on multiple factors.

The A/B have no ailerons, only one pair of trailing-edge wings surfaces, but otherwise the usage is the same.

As with the F-22, the horizontal tails are used asymetric for yaw control at high angles-of-attack, as the rudders become progressively less effective.
The middle F-35 picture above is showing speedbrake operation.
As for the F-22 pic, I highly suspect that this is showing the aforementioned use of asymetric tail for yaw control at high AOA. It's hard to tell for sure, and I agree that we would really need to see the video, but that really is the best explanation. It does look like the leading-edge flaps are fairly far down, which indicates an elevated AOA, that along with the lack of any discernable contrails indicates a fairly low airspeed. Makes me think the original picture has been rotated 90 degs.

Oh, and 'no' on the wing warping.
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Unread post27 May 2011, 13:18

Makes me think the original picture has been rotated 90 degs.

RC, I can assure you that the original shot has not been rotated. (I could tell you how I know, but that would reveal my secret forum identity. ;) ) The plane was in a left turn and, IIRC, rolled out shortly afterwards.
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