F-35 Approach AOA

Discuss the F-35 Lightning II
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spazsinbad

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Unread post22 Oct 2010, 08:31

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Unread post24 Oct 2010, 05:31

Model-Based Development of X-35 Flight Control Software Greg Walker 2 May 2002

http://sstc-online.org/proceedings/2002 ... /p1417.pdf (0.7Mb)

"CV - Flying and Handling Qualities and Flight Performance at Representative Mission Points"
"Validated in X-35A/B/C Flight Testing at Edwards AFB and Patuxent River NAS"
&
"Pilot Comments:
“IDLC Performance was Excellent.” (Throttle Bodes)
“Crosswind Landing was Easily Controlled.”
Airplane is Solid Through The Pattern. AOA Control is Solid. Good Control of Glideslope.”
(Manual FCLPs)

“Use of APC Reduced Workload Significantly Throughout the Pattern.”
__________________________

X-35C Field Carrier Landing Practice Videos:
http://www.jsf.mil/video/x35/x35c_fclp_high.wmv (4.5Mb)
http://www.jsf.mil/video/x35/x35c_fclp_low.wmv (0.5Mb)
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Unread post24 Oct 2010, 06:21

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Unread post04 Dec 2010, 01:13

Interesting (to me anyway) link to 'ODD' Conclusions about increasing Wind Over Deck (WOD) which will apply to any Naval Aircraft including the F-35C presumably: Scroll down the page....

http://www.f-16.net/f-16_forum_viewtopic-t-14795.html
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Unread post04 Dec 2010, 04:12



Watching them fly the pattern it's amazing the AOA difference. It's only about ~2 deg but looks more !!!!!!!!!!!!!
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Unread post06 Jun 2011, 02:08

from Paddles Monthly Newsletter June 2011 Edition

http://www.hrana.org/documents/PaddlesM ... ne2011.pdf (1.6Mb)

Next Month - July 2011 - will be info on (amongst other things): [Be There or Be Square]

JPALS Update

F-35 JSF Carrier Integration


[EDIT] Page to go watch (lower right): http://www.hrana.org/
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Unread post06 Jun 2011, 17:00

f35phixer wrote:


Watching them fly the pattern it's amazing the AOA difference. It's only about ~2 deg but looks more !!!!!!!!!!!!!


looking at the two planes though, the F/A-18 has a LOT more nose in front of the pilot so it should need to have a lower AoA to get the same visibility.
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Unread post06 Jun 2011, 21:35

One of the Naval Aircraft Design Criteria is to be able to have a good view of the meatball and lineup on carrier finals at Optimum Angle of Attack (FOV for Field of View I think it is called). The F-18 NATOPS actually has the angle for the Hornets I think (rather than the usual 'units of AoA' which can be arbitrary). One thing that the F-35C lacks AFAIK is the angle of attack indexer which is in the pilot view along with meatball and lineup. I guess if you can see through the aircraft a lot of this doesn't matter with the F-35C. Here is an excellent PDF: http://www.robertheffley.com/docs/HQs/N ... 002_71.pdf

"The FOV criterion is defined by the reference 1 as follows:
“The lowest level flight speed at which the pilot, at the design eye position, can see the stern of
the carrier at the waterline when intercepting a 4 degree optical glide slope at an altitude of 600
feet. The origin of the glide slope is 500 feet forward of the stern and 63 feet above the
waterline.”

"Figure 24 illustrates the geometry of this criterion. Although the criterion places the origin of the GS
at 63 ft above the waterline, the correct height of the GS source is 65 ft above the waterline,
reference 68. Through analysis, it was determined that this difference is not significant to the result
of AOA prediction using this criterion."
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Unread post02 Sep 2011, 10:23

The F-35 Joint Strike Fighter Project: Part 3. Thursday, September 1, 2011

http://www.sharkeysworld.com/2011/09/f- ... -part.html

"...Operations from a flat flight deck
58. The flight characteristics and landing speed of the F-35C Lightning II appear to have been designed specifically for operation from United States Navy nuclear powered strike carriers. These warships are capable of speeds in excess of 40 knots. The design approach speed for the F-35C Lightning II aircraft returning on board in a typical combat configuration, with all its original weapon load, is understood to be such that in ‘still air conditions’ the carrier will need to maintain a speed of at least 32 knots through the water during deck-landing operations.

59. The Queen Elizabeth class carriers have a design top speed of 27 knots which is insufficient for recovery of the F-35C Lightning II aircraft in a combat configuration in ‘still air conditions’ or when the natural wind is ‘light and variable’. If there is any doubt that the wind may fall to less than 5 knots, planned aircraft operations might be restricted. This therefore represents an unacceptable shortfall in operational availability and an unacceptable cost in weapons that have to be ditched before attempting landing.

60. It is understood that attempts to reduce the landing speed of the aircraft by 5 knots utilising such devices as spoilers on the wing would have an unacceptably detrimental effect on the stealth qualities of the aircraft – and would increase costs significantly.

61. If this limitation proves to be correct, the F-35C will not be a sensible option for operation from our carriers. The matter requires very early clarification."
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Unread post02 Sep 2011, 10:31

It seems to me that the CVF now with arrestor gear needs to have such that it can take the F-35C at max. landing weight at max. speed of the CVF at least (27 knots WOD) with NIL wind. If the arrestor gear setup has not been decided (another thread says next year for this) then how can this 'limitation' above be known? Seems to me to be a ridiculous assumption at this early stage - but that's the UK.
____________

INFO from previous page.

"F-35C carrier approach info: VX-23 'Salty Dogs' Joint Strike Fighter Update -LCDR Ken “Stubby” Sterbenz VX-23 Ship Suitability Department Head in Paddles Monthly - Sept 2010

http://www.hrana.org/documents/PaddlesM ... er2010.pdf (1.3Mb)

"The F-35C is 51.5 ft long and has a wingspan of 43 ft and 668 ft2 of wing area (7 ft longer wingspan and 208ft2 more wing area than the Air force or Marine versions.) It also carries 19,800 lbs of internal fuel - 1000 pounds more gas then the Air Force version. It is powered by a Pratt and Whitney F135 engine that produces 28k lbs and 43k lb of thrust in MIL and AB respectively. The max trap weight will be around 46k lbs, with an empty weight of about 35k lbs. It will fly an on-speed AOA of 12.3° at 135-140 KCAS [Optimum Angle of Attack or Donut]...."
Last edited by spazsinbad on 02 Sep 2011, 18:31, edited 1 time in total.
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Unread post02 Sep 2011, 12:03

spazsinbad wrote:The flight characteristics and landing speed of the F-35C Lightning II appear to have been designed specifically for operation from United States Navy nuclear powered strike carriers. These warships are capable of speeds in excess of 40 knots."


Epic fact fail, the CVN's top out at 33 ish knots in the main, nowhere near 40 kts.

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Unread post02 Sep 2011, 16:46

Some info from the F-35C 'drop testing':

http://www.key.aero/view_feature.asp?ID ... n=military

“…The tests were successfully carried out between March and April [2010], and included dropping CG-01 95 inches at 20 feet per second, with an 8.8 deg pitch [near Optimum AoA 12.3], two degree roll, and 133 knot wheel speed, simulating a carrier-deck landing.…”

Perhaps from this information some approach conditions to CVF can be inferred - at NIL WOD for CVF but even knowing 'wheel speed' from above link it is not known if this is the maximum wheel speed for a carrier landing. We know I believe that the runway wheel speed is much higher for takeoff while F-35A landing speed is said to be 25 KIAS higher than F-35C approach speed (with a flare reducing final touch down speed for A model : http://machinedesign.com/article/the-jo ... asons-0307) but how that applies to a carrier landing given the other unknowns about the capacity of the arrestor gear (weight of aircraft and engaging speed limits) I'll just have to scratch my nose.
_______________

Some more grist for the mill with a higher landing speed mentioned:

[original URL defunct] http://s3.amazonaws.com/ppt-download/vn ... 7DEGKZDHEQ
BETTER URL:
http://www.asdnews.com/news/27850/Vough ... for_LM.htm

"...This “drop test” is done to simulate a landing on an aircraft carrier. As a fighter jet approaches the deck of a carrier, forty-six thousand pounds of airplane is traveling at 138 knots and hitting the deck with a thud, stressing the airframe and especially the jet’s landing Vought Test Lab Simulates Jet Landing on an Aircraft Carrier gear with thousands of pounds of pressure. Every part of the gear must withstand that tremendous stress time after time with no structural failure...."
_____________________

JSF Carrier Variant Meets First Flight Goals Jun 8, 2010 By Graham Warwick

http://www.aviationweek.com/aw/generic/ ... ht%20Goals

“Handling with landing gear down was a key focus of the first flight as the F-35C has a 30% larger wing and uprated flight controls to reduce takeoff and landing speeds compared with the other F-35 variants. Knowles says the aircraft approached at 135 kt., compared with 155 kt. for the smaller-winged F-35A and B variants at the same 40,000-lb. gross weight. Takeoff rotation speed was 15-20 kt. slower, he says...."
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Unread post02 Sep 2011, 17:39

stobiewan, just happened on this PDF of a four day surge for USS Nimitz in July 1997 showing carrier speed (GPS DATA):

USS Nimitz and Carrier Airwing Nine Surge Demonstration

www.cna.org/documents/2797011110.pdf

And yes I have read the screed at the link below given by 'Maks'.
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Unread post02 Sep 2011, 17:55

'Back of the envelope' calculations would suggest that the arrestor gear mentioned below can catch the F-35C approaching the CVF at 140KIAS max (see USN LSO figures above) then said CVF needs to trundle along at only 10 knots in NIL wind conditions to make the required 'carrier landing ground speed' (approx.) of 130 knots at under 46K pounds (mentioned in USN LSO stats above).

Weekend Wings #38: The F-111 Aardvark, Part 2 Saturday, December 4, 2010

http://bayourenaissanceman.blogspot.com ... art-2.html

"...Furthermore, the US Navy (with aircraft carrier operations in mind) had specified a maximum aircraft length of 55 feet, and (most important of all) a maximum weight of no more than 50,000 pounds, for its F-111B model. This was critically important. The arresting gear fitted to US aircraft carriers had to decelerate heavily-laden aircraft from flying speed to a standstill in no more than 300-400 feet of flight deck space. The gear had to absorb all the kinetic energy of the aircraft, which could be very high. (For example, the current Mark 7 Mod 3 arresting gear on USN Nimitz-class carriers can stop an aircraft weighing 50,000 pounds, traveling at a speed of 130 knots, in a distance of only 340 feet. That means absorbing kinetic energy of well over 45,000,000 [forty-five million] foot-pounds.)..."
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Unread post05 Sep 2011, 11:12

Oh, they can cruise quite efficiently nearer the top of their speed range -- the details are covered in this useful essay from Naval Weapons:

http://www.navweaps.com/index_tech/tech-028.htm


They won't do 40 knots -and I really pointed that out to demonstrate that Sharkey is running an average of one total out and out factual howler per paragraph.

The actual point raised about F35 landing speeds and how easily or not they can be brought aboard a CVF has been interesting and I certainly wasn't confusing the messenger with the message on that one, apologies if I'd ruffled your feathers on that one,

Ian



spazsinbad wrote:stobiewan, just happened on this PDF of a four day surge for USS Nimitz in July 1997 showing carrier speed (GPS DATA):

USS Nimitz and Carrier Airwing Nine Surge Demonstration

www.cna.org/documents/2797011110.pdf

And yes I have read the screed at the link below given by 'Maks'.
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