F-35B UK SRVL info - Updated when new/old info available

Maybe it is time to accumulate SRVL info for the UK CVFs? Here is a start.

Lightning II - new agility for the 21st century

"...Onboard the Queen Elizabeth aircraft carriers, the jet would take off at its maximum weight of nearly 27 tonnes using a UK-developed ski-jump and land either vertically or using the novel UK-developed Short Rolling Vertical Landing (SRVL) technique. This would enable the jet to land at a much higher weight than is possible in a purely vertical landing.

Wg Cdr Hackett said: "SRVL is under development for the carriers but it means the aircraft would fly in at around 60 to 70 mph (around 52-61 KIAS) and then brake to a stop on the deck, without the need for any costly arrester gear. It will be able to land up to 1.8 tonnes heavier than otherwise be possible, meaning unexpended weapons can be brought back to the ship."

This is 3,968 lbs extra on top of VLBB (see below).

Source: http://www.mod.uk/NR/rdonlyres/9DEBC990 ... 2v1_2U.pdf (3Mb)

To be honest for all the hassle it will entail that does not seem like much of an increase in bring back. What is bring back in vertical landing mode?

Try searching this forum for 'SRVL' because that is one thing I myself would do. Sorry that you are disappointed in the bring back but there you go. The KPP for VLBB (Vertical Landing Bring Back) has been itemised on this forum in many threads many times over. Try searching this forum for 'Scorecard' or 'Bowman' or download this little beauty: http://www.f-16.net/f-16_forum_download-id-14791.html and search it for KPP.

So to answer about KPP it is taken directly from the 'Scorecard' PDF:

“The USMC has added STOVL performance as a service specific key performance parameter.

With two 1000# JDAMs and two internal AIM-120s, full expendables, execute a 550 foot [now 600 feet] (450 UK STOVL) STO from LHA, LHD, and aircraft carriers (sea level, tropical day, 10 kts operational WOD) & with a combat radius of 450 nm (STOVL profile). Also must perform STOVL vertical landing with two 1000# JDAMs and two internal AIM-120s, ~full expendables, & fuel to fly the STOVL Recovery profile.

The Marine Corps has used the more limiting deck launch, rather than a simple expeditionary airfield, to frame its requirement.”

Sadly there are no hard/fast figures on bringback weight because there are too many unknowns only described in words as above. There have been guesstimates but accuracy is lacking.

Attached is an old bringback approximation from:
http://www.aviationweek.com/media/pdf/J ... Update.pdf

Forget about external green stores (this is just a max load illustration not a VLBB). A 'back of a napkin' calculation gives approx. 5,000 lbs bringback. But youse knew that. So add some significant amount extra for SRVL and away you go.

How about this compilation graphic for reference. Source URLs are on each part of the graphic.

Fo what's it worth on p. 4 of the Code One magazine, 2nd qtr, 2002 the internal weapons included the MK-20 Rockeye, CBU-87/88/89, CBU-103/104/105 WCMD, and CBU-87 Gator. The artwork also depicts various marks of JDAM (noted as PIP) with an apparant seeker on the nose.

The AGM-84D Harpoon is shown as an external store but the JSOW is not (although it is included in the internal stores section.)

I am sure the weapons carried will greatly expand once UAI catches on with the manufactures.


btw, The recent F-15E JASSM integration was done through UAI (as all F-15Es since the F-15E is the SDD platform for UAI).

Had hoped that more info on STO, SKI JUMP & RVL testing would be known by now. Anyway earlier a PDF was cited on this forum about another matter (amongst other things replacing the LiftFan with a fuel bag capability). At the time I had overlooked the VLBB info repeated below for info. Performance details will have changed slightly according to info known today (rather than 2002) but good enough for the concepts involved. 'Scorecard' is the other good source. Earlier on this forum there was a discussion about 'tropical days' etc.

The STOVL Variant of Joint Strike Fighter: Are its’ Tactical Compromises Warranted?
Written by: Captain G.M. Beisbier, 01 March 2002

http://www.dtic.mil/cgi-bin/GetTRDoc?AD ... tTRDoc.pdf (54Kb)

“...STOVL JSF DESIGN REQUIREMENTS [pages 5-6]
The design requirements for the STOVL JSF mandated a Vertical Lift Bring Back (VLBB) capability of 5000lbs of fuel and ordnance on a tropical day. The STOVL JSF’s empty gross weight is 29,735 lbs, and it is equipped with a lift fan design capable of producing 39,800 lbs of vertical lift at sea level on a tropical day. An ability to produce 39,800lbs of thrust minus 29,735 lbs gross weight and 3000 lbs of thrust to safely maneuver the aircraft equals 7,065 lbs of VLBB. As a result the STOVL JSF thirty percent more VLBB then the requirements document mandated (Killea). This means in a worst case, sea-based scenario the STOVL JSF is more than capable of conducting a vertical landing with 4000 lbs, vise 2000 lbs, ordnance, plus two 325-lb radar missiles, and 2200 lbs of fuel for an approach, vertical landing, and reserve (Killea)....”

Creepy HUH?

F-35 Lightning II Program Status and Fast Facts September 5, 2012

http://f-35.ca/wp-content/uploads/2012/ ... 5-2012.pdf (164Kb)

"...BF-1 accomplished the first F-35 five Creeping Vertical Landings (CVLs) on August 23...."

Creepy Vertical Landings!

http://f-35.ca/wp-content/uploads/2012/ ... 5-2012.pdf

- BF-1 accomplished the first F-35 five Creeping Vertical Landings (CVLs) on August 23.

I've yet to find a document for definition of "CVL" for the F-35B. Needless to say, now that the Brits have reconsidered the F-35B the resurgence of the SRVL envelope will become a lively discussion "once again". Perhaps the CVL is to address the SRVL requirement.

The F-35B has proven the VL (Oct, 2011) on the USS Wasp (LHD1) and all current landing operations at Eglin are conventional landings. LHA/ LHD have a 820 ft./ 844 ft. flight deck (106 ft. beam/ 35 ft. wingspan) with 20+ knots WOD capability.

Is the F-35B program now assessing the "lift on wings" coupled with the VL to allow increased bring back capacity for the envelope expanders?

Creepy landing may now be in order!

Just adding old info for reference... From page 37 of the VLT 'Possibility small STOVL carrier USN/USMC' there is this PDF with now 'old but interesting' insight into the USMC F-35B FUEL VLBB. Whether it applies today I claim not to know. However long discussion about how UK is likely to operate F-35Bs suggests that it will be similar to their Harrier Ops with a quick fast landing first time. You betcha.

VLBB Graphic has been reworked and reattached below:

The STOVL Joint Strike Fighter – From a Harrier Skeptic 2002 Captain A.R. Behnke USMC

http://dodreports.com/pdf/ada520417.pdf (129Kb)

http://www.f-16.net/attachments/the_sto ... 02_200.gif

http://www.f-16.net/index.php?name=PNph ... ist#206678

Repeat here of excerpts from a very long article about many testing things at PaxRibber but worth it. Mebbe we will see some info about SRVL and ski jump testing soon. [ excerpt from here: http://www.f-16.net/f-16_forum_viewtopic-t-20505.html ]

F-35 Flight Testing At Pax [excerpt] By Eric Hehs 15 October 2012

http://www.codeonemagazine.com/f35_arti ... tem_id=110

"...While many test points are shared across all three variants of the F-35, others are variant-specific. The vertical lift capability of the F-35B, for example, creates a unique flight envelope that goes all the way down to zero airspeed at zero feet altitude. “The F-35B can fly backwards,” noted Eric Faidley, a Lockheed Martin flight test engineer assigned to BF-1. “In fact, its maximum backwards groundspeed is thirty knots.”

The only time an F-35B might hover at thirty knots in reverse in an operational setting would involve an overshot landing, Faidley explained. “In such instances, pilots would typically not back up and, instead, go back around in the pattern and attempt another landing,” he said....
&
"...Pilot Perspectives
All the F-35 test pilots at Pax are qualified to fly both variants. A subset has the qualifications necessary for executing STOVL test missions, that is short takeoffs and vertical landings. The ease of operating the aircraft in STOVL mode allows that test capability to be distributed broadly among the pilots. “A number of our pilots came here with no STOVL experience, but now they are flying STOVL test missions,” noted Etz.

“The ease of landing the B-model in STOVL mode is unprecedented,” explained Taylor, who had no STOVL experience before joining the F-35 ITF at Pax. “In the Harrier world, learning to operate in STOVL mode takes months of training. For us it is a couple of flights in the simulator and one, maybe two, flights in the airplane, because it is so intuitive. It is easy to land the F-35B in STOVL mode. We will never hear a Harrier pilot say the AV-8 is easy to land. The F-35B will hold whatever condition you command it to hold. It is like driving a perfectly aligned car down a perfectly straight highway with no wind. The F-35B will go straight until you tell it to do something else.”

“One of the beauties of this airplane is that it is so simple to land,” added Dan Levin, a Lockheed Martin test pilot and lead test pilot for the ITF at Pax. “Harrier airframes burn up about half their life in training pilots to land vertically. Landing vertically in a Harrier is a complex task. I’m a fixed-wing fast-mover pilot, and I was ready to perform STOVL operations after ten minutes in the simulator. STOVL operations are simple and intuitive. The flight control system is automated in the right ways. The pilot doesn’t even notice the transition between conventional flight and STOVL mode.”...

...Ease of vertical and carrier landings promises to significantly reduce the training time needed for these operations with the F-35B and F-35C, when compared to the aircraft the two variants are replacing. “The training required to keep a pilot comfortable in the STOVL environment is going to go to near zero,” Levin said...."

Nice new photo of F-35B aboard USS Wasp last year. CAPTION: "The initial sea trials for the F-35B were conducted in October 2011. Photo by Michael D. Jackson": http://www.codeonemagazine.com/images/m ... 7_3248.jpg

This article otherwise has lots of info about various testing matters (testing in a good way).

Interesting F-35B photo from the sea trials.

From the article --

"The only time an F-35B might hover at thirty knots in reverse in an operational setting would involve an overshot landing, Faidley explained. “In such instances, pilots would typically not back up and, instead, go back around in the pattern and attempt another landing,...”

Rather than opine about operational stuff, flight test engineers should stick to flight test engineering. The jet hovers just as well at spot 4 as it does at spot 7 or 9. Well trained pilots will stop the jet alongside the ship and let the ship catch up (in a fashion). Depending on the relative wind, that may constitute "backing up" -- or it may not. Beats the heck outta spinning it once in the pattern to the tune of 2-3x total fuel burn.

...Depending on the relative wind, that may constitute "backing up" -- or it may not...

a back pedal or two is definitely not a "Bolter"! Finessing an "X -marks the spot" should be interesting in gusting (less than hurricane) cross winds. Not exactly the SRVL calmness the academics are wishing for.

There will be a limit for gusting cross winds for a VL, which I gather the ship can adjust by a heading/speed change to get under whatever crosswind wind limit. A quick 'hover taxi' just outboard may be in order - if it is allowable. All pilot accounts stress how easy it is to fly the F-35B in STOVL mode making all kinds of adjustments possible during a difficult condition VL.