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

[bigjku]

Well the Harrier managed it.

Not very often. The unprepared field concept was not really utilized in combat on any regular basis. It was an idea for having an air force survive in an environment ripe with tactical nuclear and chemical weapons. In those circumstances you would have used the capability. Since no one is really planning around that basis anymore clawing back capability and not making the VTOL aspect a requirement makes all the sense in the world.

[spazsinbad]

Nothing on SRVL for a long time but here is an OLD but NEW video about preliminary Sim Modelling before USS Wasp first VL for the F-35B VIDEO. I'll guess that a lot of sim work will precede actual SRVLs aboard CVF or on land beforehand. I guess the SKI JUMP can be modelled also.

F-35B Manned Flight Simulator (2011) VIDEO

http://www.youtube.com/watch?feature=pl ... gZz7o_VEjA

"Published on Nov 19, 2012
Courtesy: U.S. Naval Air Systems Command/NAVAIR
Watch how F-35B Lightning II Joint Strike Fighter test pilots and engineers use flight simulators to make flight testing more efficient and safer, particularly for the initial ship trials on USS Wasp (LHD 1) in October 2011."

[quicksilver]

The biggest challenges for SRVL are misalignment of the aircraft's fwd motion with the landing area (resulting in lateral drift after touchdown), and lack of a wave-off capability after touchdown. If you go back to the Qinetiq VAAC trials, most of the emphasis was on touchdown accuracy and rollout distance on a ship in low sea states, i.e. benign deck motion.

[spazsinbad]

A lot of information about SRVL is not on this thread but on other threads. There is an ability to have the aircraft touchdown point optimised for the sea state/ship movement and WOD. IF WOD is down centreline and aircraft is on centreline during approach how is there misalignment? Actual wheel speeds at touchdown will be slow if SRVL conducted at 60 KIAS with a WOD of 30 KIAS. IF natural wind high then ship speed can be slow if HIGH WOD is a problem (which is the case for conventional carrier approaches). In any case if an SRVL is deemed to risky then the aircraft can ditch stores/fuel to carry out a Vertical Landing which by every account is much safer in any circumstances. No risk to the aircraft then.

I can get quotes about ability to use SRVL in high sea states if required - otherwise these statements are on other threads. SRVL may not even be a requirement according to this:

JSF programme to proceed with UK-specific land-based carrier trials Gareth Jennings 09 Jul 2012

http://www.janes.com/events/exhibitions ... oceed.aspx

“...With regard the SVRL landing technique, which is designed to increase the aircraft's fuel &/or weapons bring back capacity, Wilson said that the Program Office is continuing the support the UK-specific work in this field, although he added that the UK government has not yet decided if it will adopt this technique on the 2 Queen Elizabeth-class ships (CVF) when they enter service....”

"Never mind the quality - feel the width" and forget about the no longer required JBD seen in this model view perhaps of a low and slow SRVL approach: http://navy-matters.beedall.com/cvfimag ... ct04-1.jpg Other info from: http://navy-matters.beedall.com/cvf1-01.htm & http://navy-matters.beedall.com/cvf1-02.htm
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The BEDFORD ARRAY will help a lot and may become a feature of new approach technology - software and hardware - aircraft and approach aids - for future (CVFs) CVNs. See 'What Future Beholds': http://www.hrana.org/documents/PaddlesM ... st2011.pdf (2.2Mb)
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Paddles Monthly August 2011
What the Future Beholds... Dan "Butters" Radocaj
Test Pilot/LSO VX-23 Ship Suitability

http://www.hrana.org/documents/PaddlesM ... st2011.pdf (2.2Mb)

"...We may also need to add another lens-type glideslope indicator. One idea is called a Bedford Array. You can see in Figure 1 that a Bedford Array is like a lens spread of over the length of the LA. Unlike an IFLOLS which has 12 cells that are always on to create a glideslope reference, the Bedford Array is a set of Christmas lights and only the light corresponding to current position of the touchdown point is illuminated. Just as the dynamic touchdown point moves across the deck on the LSODS screen, the Bedford Array lights would “move” forward and back across the deck corresponding to the dynamic touchdown point. Figure 2 shows what your HUD may look like. You keep the ship stabilized velocity vector on top of the Bedford light that is illuminated. The datum is a reference line in your HUD. As long as the 3 all line up you are on glide path.

A Bedford Array and a ship stabilized velocity are indicators of glideslope that will show you if you are off glideslope more precisely but they still don’t make the airplane respond differently...."

[spazsinbad]

A consolidated graphic from above source with text: http://www.hrana.org/documents/PaddlesM ... st2011.pdf (2.2Mb)

[spazsinbad]

And now for something completely different...

Trials Ahead for Navy Carrier Landing Software by Armed Forces International's Defence Correspondent 21/10/2011

http://www.armedforces-int.com/news/tri ... tware.html

[spazsinbad]

Complete text (not yet proofread) of the patent application for Bedford Array is here on this forum: http://www.f-16.net/index.php?name=PNph ... rvl#200269

Otherwise here is a précis graphic from: http://www.freepatentsonline.com/20110121997.pdf

[quicksilver]

You might note that for the most part the discussions of the Bedford Array are about glideslope, leaving the question of lateral movement of the aircraft relative to the touchdown zone assumed to be aligned (as does an IFLOLS). IMO, that's a large assumption.

In an arrested landing by conventional tailhook-equipped aircraft, not only is the rollout distance after touchdown attenuated by the cable, so is lateral movement. 40 knots relative to the ship sounds really slow until one thinks about unrestrained lateral movements after touchdown. How would we feel about the risks associated with an unrestrained jet being taxied around the deck at 40kts? Not real good I'm bettin'. Same will eventually arise in the SRVL discussion.

Then of course, is the matter of a go-around after touchdown. The propulsion system goes to idle at wow...

[spazsinbad]

You seem to assume that a straight in approach with wind down the deck with the ship moving into the wind causing the wind to be straight down the deck to be the same as the situation with an angled deck carrier. It is not. Less reason or NO REASON to have any lateral movement by the aircraft at touchdown in an SRVL with ideal WOD. And look at the width of the landing area on a CVF (which is not a CVS).

Conventional landings along an angled flight deck have a built in tendency to be slightly off centreline and/or slightly not aligned fore and aft aircraft nose/tail with the angle deck centreline. This will always be an issue whilst the angle deck is moving from left to right and not only forward during a conventional carrier approach with the WOD - down the angle as best it can - with the ship always moving from left to right during the approach by the approximate amount of the angle deck angle, out of wind to stbd. Pilots are always quickly nibbling to the right to remain lined up on centreline from the beginning of the approach. There is no discernible or should not be discernible crabbing down the centreline. However as pointed out in another thread I have read that the velocity vector in a Hornet HUD can be placed on the 'crotch' to help keep line up (during an approach) but nevertheless the aircraft ideally should be fore/aft nose/tail aligned with the centreline.

If the aircraft is not aligned and drifting then it may well be waved off by LSO for being out of acceptable limits for such a condition. A late lineup correction can be hazardous so if 'at the ramp' the line up is not good then often the pilot/LSO accept the slight deviation to have a successful arrest with the arrested rollout being a bit wonky - usually going left. Apparently newbies in T-45Cs do that all the time - are drifting from right to left on touchdown which condition is exacerbated during arrested rollout.

The SRVL - IF USED - will have much better flat deck landing condition as described. There will be weather conditions / sea conditions limitations for SRVL on CVF which if exceeded will make the SRVL hazardous for sure. The same applies to a conventional carrier landing. HOWEVER the conventional bod has no other choice except depart for a landing ashore if possible whereas the F-35B baby can dump the excess baggage and do a VL. Problem solved.

As for the waveoff for the F-35B during an SRVL which will have the engine perhaps going to idle at touchdown. Do you know this as a fact? Perhaps the switch will know that for an SRVL it does not go to idle but will do so at pilot discretion? Problem solved.
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We cannot see the IFLOLS in this 'pilot head cam' view of a T-45C catapult to arrest carrier circuit but at the end I believe we see the right to left drift phenomena during the arrest rollout - what a bad lad he is. But good on him for putting the video online.

Lap Around The Boat T-45C

http://www.youtube.com/watch?v=aw4dZ2bJ ... r_embedded
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Illustration of the carrier angle centreline moving from left to right with a T-45C carrier circuit is from their online pubs. Let me know if URLs needed.

[spazsinbad]

Screenshot(s) from the 'Lap Around the Boat' video above. First one shows the aircraft getting back to centreline after being lined up right at beginning of approach (lined up with the stbd ladder line defining landing area). Of course due to unknown parallax errors due head camera position it is difficult to compensate for what view the pilot is actually seeing. Anyway the screenshots do illustrate the point about being lined up correctly is important with the last screenshot showing how much the aircraft is off centreline after drifting from right to left during arrest.

Conventional carrier landings are precise (as best they can be from 'the start to arrest'. IF NOT the LSO will wave the offender off or bad things will happen.

3rd screenie shows the aircraft 'at ramp' or beyond with the nose NOT fore and aft so it is drifting from right to left but on centreline. Apparently this situation is OK on the CVN with newbies. NOT SO on HMAS Melbourne for example with a very small - not wide - landing area. 4th screenie will show the right to left drift result at end of arrest.

IF anyone here has not heard an LSO debrief then that can be arranged. Note that the first T-45C arrest at beginning of the video shows it ending up to left of centreline (by not that much). As mentioned it apparently is difficult for the Goshawk to keep on centreline on CVNs with the 9 degree angle deck. For A4Gs on MELBOURNE with a 5.5 degree angle things were a little easier - but did I mention the small landing area?

[quicksilver]

Anyone ever let you taxi on deck at 40 kts?

And if you're dumping stuff in the drink, that defeats the purpose of the capability.

No one is arguing against the idea, it's just not gonna be that easy in an operational context when ship roll, swirling winds and other aircraft and people in proximity are factors.

[spazsinbad]

What has that got to do with anything? Apparently in an actual SRVL (not carried out by the way - earlier only approaches to low waveoffs were carried out) only via computer simulation for the moment there is not a perceived problem. You seem to forget that the wind will be straight down the deck which is a very big benefit. Any ship movement is being adjusted for as explained by the Bedford Array abilities.

Different aircraft will have different taxi/wind speed restrictions with special precautions if it is deemed necessary to taxi (very slowly) in difficult wind conditions because during taxi on deck the ship may not be pointed into the wind and it may well be turning also. For an A4G wind conditions could be critical. Drifting from right to left just before touchdown on a moving deck was especially critical as evidenced by a movie / screenshot I believe already on this forum. I'll look for them.

However just making a question without any other detail at this stage is a little silly. What is your point about taxiing what aircraft on deck at 40 KIAS wheelspeed under what circumstances. I'll guess - NOT ONE. But then again I was not trying to land at that wheelspeed without being arrested. You sure do not understand what an SRVL is IMHO.

[spazsinbad]

'quicksilver' added extra text paragraphs to first sentence only original post: "Anyone ever let you taxi on deck at 40 kts?

And if you're dumping stuff in the drink, that defeats the purpose of the capability.

No one is arguing against the idea, it's just not gonna be that easy in an operational context when ship roll, swirling winds and other aircraft and people in proximity are factors."

OK we agree. However dumping stuff in the drink is more important (in context) if a satisfactory VL can be carried out rather than a dangerous (lose the ship/ lose the aircraft) SRVL. NO?

I'll have no problem if the SRVL is found to be wanting and is never used NOR required ever on the CVFs. That is a possibility. You may agree that the Brits have been investigating this SRVL for more than a decade now. During this process the SRVL was found to be worthwhile to pursue but time will tell from whatever tests are carried out at PaxRiver and on CVF in 2018 if so deemed.

As for 'swirling winds' then they are less of an issue on CVF with WOD straight down the landing strip. YES the 'burble' is an issue for angle deck carriers but I'll wager it is insignificant or not evident on CVFs. The Bedford Array takes care of ship movement.

Here is a good description of how precise the SRVL will be and I'll say that includes centreline accuracy... NOT forgetting the usefulness of JPALS when it is in service with centimetric accuracy.

JSF To Develop Landing Technique For U.K. Carriers Oct 15, 2010 Graham Warwick

http://www.aviationweek.com/aw/generic/ ... /15/03.xml

“While the future of the U.K. Royal Navy’s two new aircraft carriers is uncertain, Lockheed Martin has been awarded a $13 million contract to incorporate shipborne rolling vertical landing (SRVL) capability into the F-35B for the U.K.

SRVL will increase the payload that the F-35B can bring back to the carrier by 2,000-4,000 lb. above what is possible with a Harrier-style vertical landing, reducing the need to dump unused weapons or fuel before recovery.

The maneuver involves landing at a slow forward speed so that some wing lift is available to supplement lift provided by the short-takeoff-and-vertical-landing (Stovl) propulsion system.

The 2 Q. E. Class carriers are designed around the STOVL F-35B....

...Development of the recovery technique by the Joint Strike Fighter team, Qinetiq and the U.K. Defense Science & Technology Laboratory required several potential safety hazards to be overcome, says Richard Cook, BAE Systems SRVL project lead. He spoke at last week’s International Powered Lift Conference in Philadelphia.

These included risks of the aircraft hitting the stern of the carrier on approach; the deflected main engine nozzle striking the deck on touchdown; exceeding the gear strength; and insufficient stopping distance after touchdown.

The result was development of a flexible SRVL maneuver in which the pilot flies a constant Earth-referenced glideslope to touchdown on the moving deck, at which point the aircraft de-rotates and brakes.

The maneuver uses a shipboard visual landing aid called the Bedford Array. This is an array of lights on the deck centerline that provides a glideslope indication stabilized for ship heave and pitch.

The lights illuminate based on ship motion to provide a stabilized aimpoint for the pilot. This array is used in conjunction with a special velocity-vector symbol and glideslope scale on the pilot’s helmet-mounted display.

Aligning the helmet symbology with the aimpoint provided by the lights on the deck allows the pilot to clear the ship’s aft ramp and touch down at the planned point with the specified descent rate, Cook says.

Flight tests of the SRVL were conducted on the French Navy carrier Charles de Gaulle using the Vectored-thrust Aircraft Advanced Control testbed Harrier, which was programmed with F-35B’s control laws.

Cook says the U.K.’s threshold & objective bring-back payload goals are “conditionally achievable” with SRVL, with further development required through flight trials of the F-35B and tests with the first Queen Elizabeth carrier.”
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Likening an SRVL wheelspeed landing at 40 knots compared to a conventional carrier arrested landing at approx. 100-10 knots is like comparing a 'parking bingle' to the mythical 'controlled crash'.

[spazsinbad]

A KPP graphic from the Knudsen brief from Jan 2007 Knudsen brief: http://www.f-16.net/f-16_forum_download-id-11277.html (PDF 6Mb)

[spazsinbad]

If the LordHighPooBah's statement is true then we can decrease the 'bingle' speed to 35 knots wheelspeed from previous 40 knots if SRVL KIAS is 60...

Assembly of New Royal Navy Air-craft Carriers Gets Underway In Fife
(Source: U.K Ministry of Defence; issued September 21, 2011)

http://www.defense-aerospace.com/articl ... erway.html

“...Chief of Defence Materiel, Bernard Gray, said:

...The Queen Elizabeth Class carriers will be the centre-piece of Britain's military capability and will routinely operate 12 of the carrier-variant Joint Strike Fighter jets, allowing for unparalleled interoperability with allied forces.

Each carrier will have nine decks, plus a flight deck the size of three football pitches, & two propellers weighing 33 tonnes — nearly two-and-a-half times as heavy as a double-decker bus — driving the ship at a maximum speed of over 25 knots (46km/h)....”