UK MOD in a muddle over F-35C

spazsinbad · by **spazsinbad** » 03 Oct 2018, 17:56

Appreciate the detail and that all this stuff appears elsewhere in different form. It seems not only I need to be reminded about all the complicated bits & pieces about STOVL in which I have no experience whatsoever but noted the extra tidbit above which I do not recall seeing before. I'll add the engine cycles the power VERY QUICKLY to maintain equilibrium.

spazsinbad · by **spazsinbad** » 03 Oct 2018, 18:14

Nite Picks E-mailed:

zerion · by **zerion** » 03 Oct 2018, 18:24

quicksilver · by **quicksilver** » 03 Oct 2018, 19:41

spazsinbad wrote:”...STOVL in which I have no experience whatsoever...”

They’ve made it so easy that even old tailhookers can do it... :wink:

johnwill · by **johnwill** » 03 Oct 2018, 21:02

spazsinbad wrote:Appreciate the detail and that all this stuff appears elsewhere in different form. It seems not only I need to be reminded about all the complicated bits & pieces about STOVL in which I have no experience whatsoever but noted the extra tidbit above which I do not recall seeing before. I'll add the engine cycles the power VERY QUICKLY to maintain equilibrium.

Spaz, i'm guessing that small, quick changes in engine thrust for equilibrium are done with nozzle exit area changes, not fuel flow or rpm changes. A question, do the wing thrusters have a constant vector angle or are they variable?

spazsinbad · by **spazsinbad** » 03 Oct 2018, 21:26

'JW' I was just riffing about the engine cycling at 0300 my time and then I had to crash - perhaps remembering rongly? I have a heap of info about STOVL ops that has been collated a few times now but perhaps not updated recently for PDF.

steve2267 · by **steve2267** » 03 Oct 2018, 21:28

johnwill wrote:
Spaz, i'm guessing that small, quick changes in engine thrust for equilibrium are done with nozzle exit area changes, not fuel flow or rpm changes. A question, do the wing thrusters have a constant vector angle or are they variable?

In the papers by Dr. Bevilaqua that I have read, the good doctor states that varying the nozzle exit area via the nozzle tail cone affects the amount of power transferred to the lift fan, and that there is little delay (or "slop"?) between nozzle actuation and actual power or thrust changes which greatly enhanced (or simplified?) the ability to control the fore- and aft- vertical lift amounts.

quicksilver · by **quicksilver** » 03 Oct 2018, 22:16

johnwill wrote:
spazsinbad wrote:Appreciate the detail and that all this stuff appears elsewhere in different form. It seems not only I need to be reminded about all the complicated bits & pieces about STOVL in which I have no experience whatsoever but noted the extra tidbit above which I do not recall seeing before. I'll add the engine cycles the power VERY QUICKLY to maintain equilibrium.

Spaz, i'm guessing that small, quick changes in engine thrust for equilibrium are done with nozzle exit area changes, not fuel flow or rpm changes. A question, do the wing thrusters have a constant vector angle or are they variable?

JW, the design utilizes a two-door shutter (Harrier used a singleton) which would seem to lend itself to the idea of some directional control vice simple variability of exit area. One can also find some vague references to the idea, but I don't recall and have never asked. See this link for good pics from spaz some years ago --

viewtopic.php?t=18095

spazsinbad · by **spazsinbad** » 03 Oct 2018, 23:55

LM QE F-35B FLICKR pics look good: https://www.flickr.com/photos/lockheedm ... 8760927062

Standard LM PR ski jump arstickle:

The Ski Jump: Continuing the UK’s Legacy of Carrier Strike Capability
01 Oct 2018 LM PR

"...Performing the Jump
The F-35B automatically positions the control surfaces and nozzles for takeoff, a unique capability compared with previous STOVL (short takeoff and vertical landing) aircraft. Such automation frees up pilot capacity and provides an added safety enhancement. The aircraft treats the take off just like a regular short take off until it recognizes the six-degree per-second pitch rate and six-degree pitch angle about half way up the ramp.

The horizontal tails and nozzle then automatically maneuver downward, and the vane box does not budge. The vane box sits directly under the lift fan and directs the airflow to allow for the proper lift off the surface...."

Photo: https://farm2.staticflickr.com/1932/311 ... 22_o_d.jpg (4.6Mb) [note pilot has HMDS NITE VISOR UP ie. old HMDS III]

Source: https://www.f35.com/in-depth/detail/how ... mp-takeoff

Animated F-35B: https://media.giphy.com/media/3MbRAqF3r ... /giphy.gif (3Mb)

spazsinbad · by **spazsinbad** » 04 Oct 2018, 00:25

Never used a digital camera however the EXIF info for the night photo earlier is awesome:

"Image Description - BF-4 Flt 511 Sqn Ldr Andy Edgell and BF-5 Flt 374 Mr. Peter Wilson, Night flying aboard HMS Queen Elizabeth on 29 Sep 2018 Make - NIKON CORPORATION
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Date Created - 2018:09:29
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Digital Creation Time - 18:54:51
By-line - Dane Wiedmann
By-line Title - Flight Test Photographer
Copyright Notice - Lockheed Martin
Caption- Abstract - BF-4 Flt 511 Sqn Ldr Andy Edgell and BF-5 Flt 374 Mr. Peter Wilson, Night flying aboard HMS Queen Elizabeth on 29 Sep 2018
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Authors Position - Flight Test Photographer
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https://www.flickr.com/photos/lockheedm ... 760927062/

spazsinbad · by **spazsinbad** » 04 Oct 2018, 01:37

Cringeworthy Musick and the title is just pure laziness. YouTube initially does not recognize 'dashes' so re-insert them!

F35 Lightning jets on HMS Queen Elizabeth | Royal Navy https://www.youtube.com/watch?v=jYv4duwu2p8

spazsinbad · by **spazsinbad** » 04 Oct 2018, 04:49

Attached is a five page PDF extract from the titled excerpt below. Should answer all questions about the LIFTingSYSTEM.

F-35 Air Vehicle Technology Overview

"...5. Roll Post Nozzle Development
The F-35B STOVL lift system uses roll nozzles in each wing to provide roll control in powered-lift operation. The roll nozzle controls thrust by varying the nozzle area using two hinged flaps. Unlike the reaction control systems on legacy vertical and/or short takeoff and landing (V/STOL) aircraft, the F-35 roll posts produce about 10 percent of the vertical thrust through redirected engine fan air. The port and starboard side roll post systems are part-number common and interchangeable, providing improved maintenance flexibility. Actuation for the nozzle flaps is provided by a twin-motor, hydraulic, rotary actuator. External, hydraulically actuated aircraft doors on the underside of the wing are opened in powered-lift operation to provide an exit aperture for roll post thrust.

A key challenge in transitioning to the F-35B was providing adequate roll control authority and rate for store asymmetries and fuel imbalance. The roll post nozzles were positioned as far outboard as the internal wing structure would allow to maximize the moment arm. Main engine fan air to the roll posts was increased to the extent possible while maintaining adequate flow to cool the exhaust liner. Architectural changes in full-authority digital engine control were made to minimize the time delay from roll moment command to roll nozzle actuator response...."

spazsinbad · by **spazsinbad** » 07 Oct 2018, 00:47

F-35B Lifts OFF of QE Ski Jump to Escape Melting Deck (I think). And a stand easy afterwards.

popcorn · by **popcorn** » 07 Oct 2018, 01:03

Should one of the wing nozzles fail I'm guessing the FCS shuts down the other one to compensate? Raise the butt pucker factor for a VL ...

zerion · by **zerion** » 07 Oct 2018, 01:45

Royal Navy Image Archive

http://213.122.161.212/fotoweb/Grid.fwx ... oSearch=Go

Anyone know how to get access?