Shipboard Rolling Vertical Landing - The saviour of Dave-B?

[You Sir, Name!]

UK to extend rolling carrier landing research for JSF (http://www.flightglobal.com/articles/2008/08/21/314976/uk-to-extend-rolling-carrier-landing-research-for-jsf.html)

The UK Ministry of Defence (http://www.mod.uk/DefenceInternet/home) is continuing research to refine a hybrid shipboard rolling vertical landing (SRVL) technique, potentially to be employed as the primary recovery mode for Lockheed Martin F-35B Joint Strike Fighters (http://www.lockheedmartin.com/products/f35/) operating from the Royal Navy's two Future Aircraft Carriers (CVF).
A programme of MoD-sponsored research work, including technical advice from the Defence Science and Technology Laboratory (Dstl), has already concluded that SRVL would offer a significant increase to the F-35B's payload "bring back", without any fundamental platform or safety issues. However, further investigations are planned to address a range of optimisation and integration issues, says Martin Rosa, JSF technical co-ordinator in the Dstl's air and weapon systems department.

http://www.flightglobal.com/assets/getAsset.aspx?ItemID=23837 © USAF

An SRVL involves a short take-off and vertical landing aircraft performing a "running landing" on to the carrier flightdeck, using air speed to provide wingborne lift to complement engine thrust. The touchdown position on an axial flightdeck is similar to that of a conventional carrier - about 45m (150ft) from the stern, but no arrestor gear is required, as the aircraft uses its brakes to come to a stop within a distance of 90-150m. The technique could allow an F-35B to recover with an extra 907kg (2,000lb) of weapons and fuel, or reduce propulsion system stress and increase engine life.
The Dstl began work to examine the feasibility of employing the SRVL manoeuvre in the late 1990s. Following a series of simulation-based studies, the MoD's investment approvals board in July 2006 endorsed the requirement as part of its F-35B-based Joint Combat Aircraft programme.
Speaking at the Royal Aeronautical Society's (http://www.raes.org.uk/) International Powered Lift conference in London in July, Rosa said SRVL studies have shown that "a way forward exists to achieving operationally useful increases in bring-back, compared to a vertical landing, on board CVF with an appropriate level of safety". But "uncertainties remain in terms of the scope of an operational clearance and the potential impact on the sortie generation rate for CVF".
Qinetiq (http://www.qinetiq.com/) used its VAAC Harrier testbed to perform representative land-based flight trials and a ship-based SRVL demonstration aboard the French navy's aircraft carrier Charles de Gaulle last year.
Rosa said past work has also identified a promising visual landing aids (VLA) concept optimised for SRVL and stabilised against deck motion. "We will continue to mature the SRVL-optimised VLA arrangements, look at the possible 'tuning' of the JSF flight-control laws, and further study the effect of SRVL on the CVF sortie generation rate," he said. The capability's full scope will be confirmed after flight trials from the 65,000t vessels, which are due to enter service in 2014 and 2016, respectively.
Other forthcoming work includes optimisation of the approach profile, agreement on the optimal post-touchdown technique, and mitigation for failure cases, such as a burst tyre on touchdown.

[Jetex Jim]

Very interesting.
Rosa said past work has also identified a promising visual landing aids (VLA) concept optimised for SRVL and stabilised against deck motion. "We will continue to mature the SRVL-optimised VLA arrangements, look at the possible 'tuning' of the JSF flight-control laws, and further study the effect of SRVL on the CVF sortie generation rate," he said. The capability's full scope will be confirmed after flight trials from the 65,000t vessels, which are due to enter service in 2014 and 2016, respectively.


The investigation of visual landing aids, and tweaking with control laws suggests that SRVL may not be as straight forward has some have indicated.

Too bad the old, 'it's better to stop and the land, than land and then stop', idea seems to be, being eroded.

[Engines]

Good to see Martin Rosa getting some visibility - I've known him for some years - he really knows his STOVL stuff, and has made major contributions to the UK's JSF effort.

JJ - looking at VLAs and possible flight control law optimization is EXACTLY what the team need to be doing to get the best out of SRVLs. If they go down this route (and I'm a proponent of it) a good VLA is a must for safety and best sortie rate. The flight control 'tuning' being described could well be applied to other JSF scenarios - it's required to do land based RVLs for the USMC as part of its basic requirement set.

The old 'it's better to stop and then land, than land and then stop' is still good, but how about 'It's better to slow down to a near crawl then land, than land at 140 knots and then hook a wire to come to a halt'? Not as snappy, but worth thinking about.

[Modern Elmo]

The old 'it's better to stop and then land, than land and then stop' is still good, but how about 'It's better to slow down to a near crawl then land, than land at 140 knots and then hook a wire to come to a halt'? Not as snappy, but worth thinking about.

How about, "It's better to be able to go around and try again, if you bolter the landing attempt?"

How about, "Shipboard Rolling Vertical Landing - The Harrier old boys club's false Messiah?" ... as if the STOVL F-35 needs to be saved by some Brits.

[Modern Elmo]

Rosa said past work has also identified a promising visual landing aids (VLA) concept optimised for SRVL and stabilised against deck motion. "We will continue to mature the SRVL-optimised VLA arrangements, look at the possible 'tuning' of the JSF flight-control laws, and further study the effect of SRVL on the CVF sortie generation rate," he said.

Yes, very well, how about an automated landing system, stabilised against deck motion, such as later model F-18's already have?

[Jetex Jim]

Engines, I suppose it depends what you mean by a near crawl.
The touchdown position on an axial flightdeck is similar to that of a conventional carrier - about 45m (150ft) from the stern, but no arrestor gear is required, as the aircraft uses its brakes to come to a stop within a distance of 90-150m.

They could always give it a hook, I suppose...





.

[Modern Elmo]

Definitely the next move for the RN's Rolling Stop Program.

"Can't you retrofit it with a sort of, er, lightweight barrier engagement device?"
Air Force Fighters & Tailhooks

http://www.aerospaceweb.org/question/planes/tailhook/f16-tailhook-2.jpg
F-16 being decelerated by a crash barrier cable

Aerospaceweb.org | Ask Us - Air Force Fighters & Tailhooks (http://www.aerospaceweb.org/question/planes/q0295.shtml)

[Engines]

Modern Elmo, JJ,

The team have looked at getting a hook on the STOVL (wasn't in response to SRVLs) and it's quite a job. The F-35A has one for land use, the F-35C has a monster one for shipboard use, but the B doesn't have the structure under the aft fuse to fit one, as it has to be left clear for the aft nozzle to swivel down.

All USN deck landing systems are stabilized against ship motion, and yes they do have an automated capability. I understand that they rarely use the full 'hands off' automated capability, but they do use the system extensively at night to aid stabilizing the aircraft on the glideslope. The work being done right now, I believe, is to assess SRVL workload against various scenarios and decide whether a full autoland capability is required.

ME - I can't support the view that SRVLs are a 'false messiah', nor do I think the Brits are trying to 'save' the F-35. SRVLs are most probably being looked at because the Brits want the aircraft to do more than the agreed specification asks for. I do agree, though, that we should aim to give SRVLs a bolter capability.

[Schiller]

"Better to stop and then land..." sez who.
Better to have the best performing aircraft you can find and then find out how to land it. That´s what professional pilots are for.

[dirty_bugger]

That´s what professional pilots are for.

...quite right! why don't we get rid of the flight control system and really make professional pilots earn their flying pay instead of trying to make flying safer...TALLY HO CHAPS....

[Jetex Jim]

Engines:
SRVLs are most probably being looked at because the Brits want the aircraft to do more than the agreed specification asks for.

This wouldn't because what is 'agreed' now is different to what was originally expected, would it?

Here's what Dr Kopp had to say on the subject in May, this year.

The saga of the weight reduction effort is a good example, as early in the SDD it was established that the airframe with systems installed was too heavy to perform, a critical definicency for the STOVL variant. This was followed by the SWAT (STOVL Weight Attack Team) effort intended to drive the weight of the design back to an acceptable number. The SWAT effort was followed by a major public relations campaign declaring publicly that the weight problem had been beaten. When the published target weight data for the JSF variants is tracked over time, it is clear that empty weight remains a major design problem. Between 2002 and 2006, the weight of the CV variant grew by 6.7%, the STOVL variant by 8.2% and the CTOL variant by 9.6%.


A look at:
Assessing Progress on the Joint Strike Fighter Program (http://www.ausairpower.net/APA-2008-03.html)
shows how the baseline weapons fit has been steadily whittled away since 2001.

[LowObservable]

On the Future Carrier thread, a poster who seems to know where his towel is suggests that the need for SRVL is driven by the definition of a "hot day", with the RN looking at hot/low pressure days that are more severe than Marine standard days... of course the Marines are stuffed anyway, since their decks aren't big enough to begin with.

[Schiller]

It´s not a question of safety. I don´t know that STOVL is any safer than cats and traps. Its just that any self repecting aviator would like to go to war with the best performing aircraft he can get. If that means he has more of a job landing it - well, so be it. He has to learn how to do that.

[Modern Elmo]

Its just that any self repecting aviator would like to go to war with the best performing aircraft he can get.

Please define "best performing aircraft" for aircraft carrier operations.

[Modern Elmo]

Here's what Dr Kopp had to say on the subject in May, this year.

The good Dr. Kopp. How are you doing there, Charley?

What do you suggest for the Fleet Air Arm? A well-chosen mix of Sukhois and F-111's?

[LowObservable]

Modern E - argumentum ad hominem, dude. You may have your opinions about Dr Kopp (who doesn't?) but the F-35's weight history is relevant to this discussion.

[dirty_bugger]

schiller - I agree that any nation should send their men/women to war in the best kit available (please note that it is nothing to do with professional aviator bollox, just best kit for purpose). however, modern procurement policy is not about best kit - it is about meeting defence targets in something that is affordable. If you want the best kit ....give us the cash! if you want the best value for money then F35 will give it to you. If you want to pmp money into british economy give it to BAES for Typhoon.

compromise baby.......

[Jetex Jim]

dirty b
if you want the best value for money then F35 will give it to you. If you want to pmp money into british economy give it to BAES for Typhoon.
Interesting, and that latter assertion is not something one could make regarding Dave-B, you believe?

From
Navy argues against Marine variant of JSF - Marine Corps News, news from Iraq - Marine Corps Times (http://www.marinecorpstimes.com/news/2007/04/defense_stovl_jsf_070430m/)

British support for the F-35B is seen by many observers as a key element in the survival of the variant in last year’s Quadrennial Defense Review (QDR). Although the QDR was completed over a year ago, the British carrier program remains a major ingredient in the STOVL program.
A British government official said Pentagon officials “periodically seek updates from the British government on the status of the carrier program — a move that some have suggested has less to do with Britain’s interest in building the ships than whether London is wavering on the raison d’être for the JSF STOVL program.”

A rather interesting way to describe it, don't you think?

Which is to say, without Dave-B BAE wouldn't be participating in the JSF manufacturing club. -- Too bad, I think, that the price of membership includes two dedicated STOVL 65,000 ton carriers. (BTW the nuclear CdG weighs in at a mere 42,000 tons)

[Question_Answer]

IIRC The VAAC Harrier successfully performed an automated VL a couple of years ago. Aren't many UAV now doing autolanding? So surely not too tricky to achieve autoland SRVL with F-35. Regarding slowing down post SRVL landing, would that be entirely down to the performance of the braking system, i.e. no reverse thrust vector? 90-150m, sounds very tight - how far does a fully laden truck (40T) take to stop on a wet road at say 50mph?

Irrespective of whatever funding cuts may be round the corner, BAES will be getting money, whether its through F-35, CVF, Typhoon, Nimrod, Astute, UCAV...............but then we do want to retain an organic defence/aerospace manufacturing capability dont we?

[Double Zero]

I notice one particularly experienced VSTOL Test Pilot is being very restrained on this subject - possibly as a lot of b----cks is being spoken !

Yes, stop then land, or nearly so; I don't reckon an approach speed of 140 kts sounds like a ' near crawl ', more like a 'near F-4' !

In WW2 the F4U Corsair was reckoned a good thing once airborne, but it took Eric Brown - with exceptional skills - to convince the USMC to use it aboard ship.

When I saw a recent claim that only 129 ( I find that figure very dubious ) Corsairs were lost in combat, and of course claimed about 4,000 kills, I would have laughed if the subject was not so sad; i.e, how about landing / training accidents - same goes may I suggest for the F-35B; and we're not even with our backs to the wall in an emergency wartime situation...

[Jetex Jim]

but then we do want to retain an organic defence/aerospace manufacturing capability dont we?

Yes, but let's face it, BAE will get a pretty big piece of the action even if Dave-C were chosen.

It would be diabolical if Dave-B became another Spey Phantom debacle. Should it turn out that SRVL is a tricky manouver, even the advantage of reduced time spent practicing landing will be lost. And the penalties of vertical lift are then going to be very hard to justify. Of course by that time the carriers will be built, (even now the excuses for how difficult it will be to retrofit the new carriers with CATS are being rehearsed) and Dave-B WILL go ahead regardless.

As I recalled in the Future Carrier thread; the Spey Phantom was always going to pay for itself in exports to re-engine F4s the world over. In fact, it did no such thing, and the RAF ended up with the worlds slowest, and most expensive F4s, all 'justified' by an alleged need to generate a bit more thrust to improve bolter performance.

I would suggest that the rational for Dave-B is starting to look at least as tenuous.

[dirty_bugger]

jetex - simple question:

Do you know what the procurement and through life costs of Dave-B are compared to that of Typhoon? If you did and it was your choice you'd have Daves coming out of your armpits!

oh oh ..... can't help this postis going to be used extensively for quotes....incoming!

[Engines]

There's a lot of supposition going on here - and that's OK, it's a discussion forum. However, some of it is a bit wide of the mark.

SRVL relative approach speed to the deck is around the 40 knot mark, I guess. The available landing area on CVF is generous (especially if we were to use an angled landing area) and the F-35B brakes are extremely powerful. Distance from the round down to the touch down point will be a key parameter. The guys working this are not going to recommend an unsafe landing method to justify buying the B. The TPs involved are experienced, smart and operationally aware. They are working to devise a safe manual technique that can be easily automated to improve safety - very much as the USN do for their cat and trap operations.

Spey Phantom - yes, definitely a good bit of work for RR, in the wake of TSR2, P1154 and HS681 cancellation. But the driver for the UK changes was the need to get the aircraft off the shorter catapults and slower carriers the UK had in the 60s. In addition, Bolter performance was a very real issue. Landing gear was beefed up and heavily modified, more weight and so more thrust required. The problem was taking an aircraft designed in detail to operate from the USN CVN flight deck, and trying to get it to work from a smaller deck on a slower ship.

When looking at taking F-35C and putting it on CVF, we could consider this piece of history....

[Jetex Jim]

Dirty B
Do you know what the procurement and through life costs of Dave-B are compared to that of Typhoon?
Well, why compare it with Typhoon? I'm talking about carrier aircraft alternatives, Dave-C.

In any case, isn't it a little too early in the project lifecycle for anyone to say what the procurement and life cycle cost are really going to be?

And that's just thinking about the cost of the aircraft. If we adopt the view that in order to justify developing Dave-B we have had to buy a couple of STOVL carriers, we add in another big chunk of change.

I'd like to see an analysis of the cost of fully automating Dave-C CAT/TRAP landings. If it's possible, and cheaper than developing Dave-B it becomes a no-brainer right? More capability, without the need to wear out the airframes practicing the basics of carrier recovery.

[dirty_bugger]

Jetex - true, but.....

Dave was designed to meet Defence Strategic Guidence 05 (and previous instantiations) and did so in spades. Dave C did it in bigger spades but cost more so it was a no-brainer to go for the cheaper version (from what I've heard!).

[Double Zero]

Granted,

I thought the 'near crawl' approach of 140kts - rather than the more likely sounding 40kts was a bit dubious.

As mentioned previously, the VAAC Harrier ( thus leading to the F-35 systems ) and to some extent the F-18E, UAV's etc have 'autoland'.

'Bring-back' seems likely to remain an issue for carrier aircraft, no matter how they land, be it cat & trap, vertically or on a rubber mat alongside !

[Engines]

F-35C is designed to operate from USN ships - CVN-68 class (Nimitz). They will be designed to use the new JPALS landing system, and it will have an autoland capability.

BUT - there is very little chance that the USN will rely only on an automatic landing system to avoid training aircrew in manual landings. F-35C CONOPS will be a development of those used for F/A-18E/F and other manned jets. Trying to go for an F-35C option without training our aircrew would be, in my view, plain unsafe.

I'd suggest that the autoland issue is not the central one for SRVLs. (The one area where it might pay off is a automated braking function). The teams at Fort Worth and Warton are, I believe, working to develop a safe SRVL capability which can be carried out manually. JPALS could then be used to provide various levels of assistance, depending on weather and operational needs.

Hope this helps,

Engines

[Jetex Jim]

Engines.
Yes the Spey story is a good one. For RR. On the strength of equipping the ARK with its single squadron of F4Ks, the entire UK F4 buy were equipped with Speys. Which cost about twice what the standard F4J was then going for. Amazingingly enough, sufficient to have procured three new carriers, (with decent sized decks) I believe. That the Spey Phantoms were pretty duff can be seen from the fact that the Air Force got rid of 'em with almost indecent haste, (to replace 'em with the lovely F3, of course) And the Luftwaffe has only just retired the last of its ancient F4s, but even these were not too shabby at the end, with AMRAAM and decent radar.

When looking at taking F-35C and putting it on CVF, we could consider this piece of history....
Well yes, but the CVFs are big boats, over 60K tons. If the frogs can operate RAFALE off the C de Gaulle, about 45K tons, are you telling me that we can only operate a STOVL off these big, brand new ships?

Plus of course by going ski jump we then have to make do with rotary wing early warning aircraft, the frenchies have E2C, and so it goes on...

[glad rag]

Engines, could you remind us all what the term co-efficient of friction refers to please?

[PPRuNeUser0211]

Jetex - I hope they haven't quite retired the last of their F-4s, as I'm pretty confident there's one coming to an airshow north of the border in the none to distant future....

[Question_Answer]

regarding the braking system - do any aircraft/could this one be designed to have ABS type systems?
How about install some very large fans/blowers on the bow of the ship to increase the WOD during finals :-)
Or if bringback is such a driver for SRVL, tow a large dinghy behind the CVF and jettison stores before transition......I'll get my coat!

[PPRuNeUser0211]

QA - most fast jet a/c have an "anti-skid" system of some kind or another. The main drama with it compared to your common garden ABS is that braking is only being applied to two wheels, thus the ABS sensor system only has two wheels to compare. Thus if you have a snag with it it can lead to you getting no braking at all!

[Jetex Jim]

Jetex - I hope they haven't quite retired the last of their F-4s, as I'm pretty confident there's one coming to an airshow north of the border in the none to distant future....


Yes indeed, those at least one squadron of those venerable Luftwaffe F4s has to soldier on until 2015! (Now there's an Air Force that knows how to get value for money!!)

[BEagle]

Good point about the μ factor of a wet, kerosened deck. Particularly in lively sea states.

Perhaps a hook-like thing on the arse end of the jet and some wires across the deck might be in order?

[Modern Elmo]

BUT - there is very little chance that the USN will rely only on an automatic landing system to avoid training aircrew in manual landings.

Avoiding aircrew training isn't the point of an automated aircraft carrier landing system. ( At least that's what they tell naval aviators. ) It's there to make landings possible in worse weather, and to assist an aviator in distress for whatever reason when necessary.

Would you say that existing IFR equipment is there to avoid crew training?

Now, everyone who's for skipping the F-35 and moving on to shipborne UCAV's please raise your hand.

[glad rag]

Don't think a complete fleet makeup of UAV's is the way to go as both manned and unmanned can REALLY complement each other operationally.

However..

....If you look at the toll of US Naval aircraft landing on bolters/incidents/accidents with aircraft who, for want of a better term, "relatively simple landing phase systems" (sorry) how do you see the complicated setup of the JSF coping? (IMO it's a fudge)

[Engines]

Glad Rag and others,

The JSF team are definitely considering deck conditions, including coefficient of friction. The USN take quite good care of their landing areas, incidentally, with frequent washes and prompt removal of fuel and oil. UK should do the same with CVF.

JSF has a very advanced braking system, large wheels and substantial brake units. Braking performance at 40 to 50 knots is good, and the system is designed to handle wet surfaces as best as laws of physics will permit.

ME, landing aircraft on CVNs with wires at 140 knots is a hazardous undertaking and not at all simple. The USN keeps accident rates low with very good aircrew, lots of very good training, lots of practice at sea, closely managed authorizations (takes a while to get night qualified and hard work to keep it) and well worked up CVN crews to run the ATC, approach, autoland and arresting systems. They are the masters at it, but it costs a fortune to do it.

JJ - Rafale performance off CdG is rumoured to be not good. The cats are a shortened version of the USN pattern, giving lower launch speeds. A problem, especially as CdG is not a fast ship. Spey buy - the F-4K buy had to equip the RN's complete fleet, a lot more than one squadron. In the end, the F-4K/F-4M split was about 50/50. Yes, it was a job creation scheme for RR - but as I said, the only real way to get F-4s to sea on UK ships. The USN had already learned that trying to convert WW2 ships to handle F-4s and larger (A-3 and A-5) was not a good way to go. Sadly, the UK just could not afford Forrestal class ships.

Best Regards

Engines

[Double Zero]

One thing I haven't seen mentioned yet - sorry if I missed it ! - is why on earth the SRVL is a 'new' idea, not designed in from the start ?

We all know Harriers like to creep forward on landing ( and certainly a bit more for take-off ! ) for reasons of hot gas re-ingestion & FOD, maybe a little wing lift - you tell me, I'm not a Harrier pilot...

Maybe the F-35B doesn't suffer as badly from hot gas into the intakes as the Harrier, what with the fan rather than close nozzles ( even the aft hot ones ).

Another point raised by a very accomplished VSTOL aircraft researcher is " how does it taxy backwards ?"- using braking Viffing - for landing rather than combat manouvres largely invented by the media - also handy for deck parking, though not easy, as related by Jerry Pook.

My father was crew-chief on a Harrier at the Paris Salon show, and after one attempt at taxying backwards then finding out the reverse castoring effect on the noseleg the hard way, it was quietly decided by all concerned to forget it unless the pilot had someone ahead directing - obviously a different deal on a carrier at war.

However braking / reverse parking thrust would seem handy to me.

As for the weight issue, remember the P1127 could barely lift itself when stripped right down to start with, but the Pegasus ended up with a lot more than twice that thrust !

[Jetex Jim]

Engines, I beg to differ, regarding your numbers of Spey Phantoms
from
Military Power: F-4 Phantom II (http://militarypower.wikidot.com/f-4-phantom-ii)
In 1964, the Royal Navy (http://militarypower.wikidot.com/royal-navy) ordered a 'anglicized' F4K, which had a wider fuselage to house the Rolls-Royce Spey, fan engines. Forty-eight machines were delivered to the United Kingdom as the Phantom FG.1. However the premature retirement of the Carrier HMS Victorious (http://militarypower.wikidot.com/hms-victorious) coupled with the prohibitive cost of refitting HMS Eagle (http://militarypower.wikidot.com/hms-eagle) meant that only the carrier HMS Ark Royal (http://militarypower.wikidot.com/hms-ark-royal) was available to operate the Phantom. As a result twenty aircraft of this order were transferred to RAF Strike Command (http://militarypower.wikidot.com/raf-strike-command), equipping No. 43 squadron at Leuchars. The twenty eight Royal Navy aircraft began trials by No.700P squadron based at Yeovilton in Devon before being passed to No.767 squadron for type conversion training, and finally becoming operational with No.892 squadron, also at Yeovilton. From March 1969 No.892 squadron made a number of cruises with these aircraft aboard HMS Ark Royal using the Phantom. In 1978 these aircraft were transferred to the RAF'S No.111 Squadron for Air Defense of the United Kingdom.....The use of Rolls-Royce Spey engines in the British Phantoms dramatically increased the unit price of the aircraft whilst decreasing maximum speed, height and performance at altitude.

Wow, 10 years worth of carrier ops from 28 aircraft. 48 F4K were made and 116 F4M, and of course, the Ms had Speys as well, and each Spey aircraft DOUBLE the price of the standard model.

Pretty pricey cocktails.

[Dan D'air]

based at Yeovilton in Devon

finally becoming operational with No.892 squadron, also at Yeovilton


Blimey!!! Not only did they transfer tho 'Tooms to the RAF in order to cut costs, they also seem to have managed the spectacular feat of moving Yeoves from Devon to a county nearer to London too!!! Just think what could be achieved if we were still using Lsd.............

[BEagle]

If I recall correctly, the UK had a substantial balance of payments crisis at the time and it was essential that a large component of the 'Fifty-fifty Phantom' (as it was nicknamed) was of UK origin. Hence the Spey.

The UK also tried to offset the cost by selling the Jetstream 3M to the US where it would have been the C-10A; that also flopped when Handley Page couldn't keep to its delivery dates. But at least the 3M wouldn't have had the awful Astazou engine, it would have had Garretts!

[Jetex Jim]

D.D

Not only did they transfer tho 'Tooms to the RAF in order to cut costs, they also seem to have managed the spectacular feat of moving Yeoves from Devon to a county nearer to London too!!!

Wot? Well didn't the RAF have a stab at moving Australia one time?

[Engines]

JJ,

I happily stand corrected on numbers. But the basic point is that the RN went for Ks as the only way to get the aircraft on board. The one plus - I believe that UK F-4s were the fastest to altitude of any variant. As you say, a pricey cocktail.

Victorious was retired on an excuse (politics) but it was the huge cost of her conversion that did for Eagle. As I posted previously, converting WW2 ships to take big and fast jets proved prohibitively expensive for the USN - the RN sadly had no real alternatives.

DZ,

RVLs on land have been there from the start on JSF - the USMC have a requirement for a short field landing. For ship operations, VLs were the only recovery method in the requirement. SRVL work is taking what the basic aircraft delivers and applying it to shipboard recoveries.

I don't think F-35B can back taxy. It was always there on Sea Harrier, and we used it plenty of times - but the CVF deck is large enough to allow aircraft repositioning via normal taxy.

Best Regards as ever

Engines

[Double Zero]

Thanks, 'Engines'.

Seems to me there are two sadly conflicting concerns here - in an ideal world, and with a little country like the U.K, one would have hoped they were both playing the same game.

Instead we have 'job creation' - usually leaving our forces with crap kit - or 'wartime desperation' - which it seems one doesn't get time for nowadays.

While the Gripen may not be the absolute bee's knees, I can't help thinking that what with that & the past Viggen & roads / flyover HAS's etc, the Swedish have much to be admired - their ladies aren't the worst I've ever seen either !

The most intelligent British decision I have heard, in military circles, was to incorporate potential for 'export features' such as extra pylons, RWR etc. into the Hawk, when the basic Ministry spec' didn't actually mention them.

Probably with a lot of thanks due to Gordon Hodson, chief designer of course.

[BEagle]

Whereas the RAF did, allegedly, 'move' Australia for obscure political reasons, at least some fishhead tried to do so physically by driving one of HM's war canoes into the only rocks for miles (nautical or otherwise) in any direction.....

[Engines]

DZ,

The JSF is probably one area where the 'job creation' label might not stick. The payback that UK industry is getting on the project is, I reckon, well in excess of what the UK MoD have paid to get on the project. No doubt that F-35B gives a bigger payback for RR, but that is by no means the whole story on F-35.

I am also a fan of the Swedes - good designs, strong and consistent defence policies and realistic requirements all play a part there, IMO.

Hawk's an interesting aircraft - it was a completely PV design in response to an overblown Staff Target for an advanced supersonic trainer (which would have needed a sort of Jag T2 to meet it). You are bang on, pylons and other features were put in with an eye to the future - I was once told that the MoD had to be dissuaded (By Hawkers) from spending a million or so to get them removed!

Beags - no allegedly about it - the RAF presented politicians a revised map of the Far East to show the ability of land based air to provide air cover for the fleet - people I trust told me that one bit of land was moved around 400 miles! Reason was to undermine the case for the carriers - but I don't subscribe to the 'evil RAF' school - sadly, it's probably more true that the RN failed to make their own case strongly enough.

Regards

Engines

[glad rag]

Thanks for the answers Engines, I don't agree that JSF/35B IS the right answer but WE of course can only offer opinions :ok:

[Jetex Jim]

Engines
The JSF is probably one area where the 'job creation' label might not stick. The payback that UK industry is getting on the project is, I reckon, well in excess of what the UK MoD have paid to get on the project. No doubt that F-35B gives a bigger payback for RR, but that is by no means the whole story on F-35.


Indeed, the costing of these projects gets pretty involved.

Commiting to STOVL means a commitment to a ski-jump deck right? Which means a commitment to rotary wing AEW, (Maritime Airborne Surveillance & Control MASC, so maybe we should also add in
(MASC unit cost + R and D) - (off the shelf cost of E2C)

best regards JJ (an interested party, a taxpayer)

[LowObservable]

"Do you know what the procurement and through life costs of Dave-B are compared to that of Typhoon?"

No, I don't. Neither does Tom Burbage, Gen. Chuck Davis, DSD(AT&L), MOD(A) or OUT(C&A) because (a) Dave has only flown a few dozen hours and (b) its first cousin, the F-22A, is missing its maintenance targets by a large margin, despite much confident briefery in the 1997-2003 timeframe about "this time we've got the LO maintenance issues sorted, honest Guv."

[Double Zero]

Engines,

Many thanks for the gen' - one point though, and I don't mean to contradict you, but isn't even the CVF a lot smaller than a Nimitz class, and they still park with the tails over the side ( better for the crew getting out than nose-over-side I suppose ! ).

As the F-35B is a lot larger than a Harrier, I imagine reverse thrust viffing midair is not considered necessary even for approach, and parking will be done by a 'tractor' as is traditional ?

Cue a project for a new super deck tug - probably a more profitable contract than the aircraft!

While I'm all for advance, wouldn't a Harrier -even allowing for lost knowledge & manufacturing capability ( all relatively available given the will ) -with AMRAAM and something like an S-3 / Osprey / Orion with buddy tanking & AEW have been a lot cheaper, therefore in a perfect world more of them, and more Type 45 destroyers ( we all know the answer to that one...).

Too late now, in the words of Basil Fawlty after banging head on table " No, it's not a dream, we're stuck with it !"

[Engines]

DZ,

CVF deck is really big for the tonnage - it's about the same area as the original Forrestal class. You are spot on - the aircraft will still need to be spotted with tails over water, but the whole deck cycle and aircraft handling routines will be very different from our current CVS. On CVF, aircraft will be taxied under their own power to areas of the deck where a short 'push back' will get them spotted. On CVS, nearly all deck moves are 'tractored' from start to finish.

The CVF team have built some really smart flight deck movements simulations and have modelled this stuff for a few years - I am told that the USN are very impressed.

As an old time Harrier engineer, I'd love to agree that a Harrier plus AMRAAM could have cut the mustard - but we had one and we junked it early. FA2. Further developments were looked at, and there were any number of projects put around by Kingston, but the fact is that the basic Harrier concept of a centrally mounted high bypass turbofan generating lift by direct jet thrust carries too many performance penalties. The X-32 showed how real they were.

JJ, I agree that going STOVL ties us in to a range of costs. The trick is how that range of costs stacks up against the costs of running a cat and trap operation. I don't know the answers, but the high priced help in town apparently do. One thing I do know is that committing to an 'off the shelf' E-2 would not be cheap. I'd also suggest that one area of our capabilities that we do not want to hand over to Uncle Sam is our organic C4ISR.

Best Regards

Engines

[Modern Elmo]

... our organic C4ISR.

A helo with a radar dangling out one side is RN C4ISR for the 21st C.?

[Jetex Jim]

Engines, sorry. You've got me scratching my head over your last remarks.

One thing I do know is that committing to an 'off the shelf' E-2 would not be cheap.

Military procurement and cheap are words rarely found in the same sentence. But the cost difference between off-the-shelf and new dev...

I'd also suggest that one area of our capabilities that we do not want to hand over to Uncle Sam is our organic C4ISR.

Ditto the remarks of the representative from Tennesse, re. organic capability. We are hardly world class in this area.

Nationally, for MRA4, should it ever actually make it into service, all the LINK11/16 is Boeing; as with the rest of the mission electronics.
E3D, well I hardly need state the obvious.

JJ

[Engines]

JJ, ME,

Sorry if I wasn't clearer. My bad.

A helo with a radar dangling out of the side - or perhaps a converted airliner with a dome scabbed on top? Neither sounds good put that way. I had heard that the ASACs SK7 have done a good job in Iraq - but again, perhaps I'm off beam here. And these days they are really a joint asset, not 'RN'. Same as all our ISTAR assets.

What I was getting at is that going cap in hand to the US for a major ISTAR (more modern acronym?) asset just ensures a loss of UK expertise in this area. My view (very probably uninformed) is that we aren't as far behind the US in all the areas as some may think. And we need to remember that in ISTAR, as in all areas, enough might be, well, enough.

E-2 and affordability - again, none of us have the detailed sums, but I've been around enough 'off the shelf' projects to realize that first, there is no product on the 'shelf' - you always end up paying for some development (e.g. Danish Merlins). Second, the US extract a good price for their exports - and the support costs can be eye watering. I'm not arguing that buying US is wrong - but it's certainly not a panacea.

Best Regards as ever,

[LowObservable]

ASaC7 is not bad by all accounts, although it would be better if it could stay up higher and longer. And to add to the point on E-2D - it is so intimately involved with the US Navy way of doing business that it might be ill matched for anyone else's needs. (Note the fact that attempts to glue the E-2 radar on to other platforms have not appealed on the export market, nor generally has the E-2.)

[Double Zero]

"Although it would be better if it could stay up higher and longer".

I've heard that before somewhere - curse that Romulan ale !

- But isn't a UAV best suited - even going to the extremes of solar power ( I think that's in the future, but know the needs of a powerful radar - and for that matter a relatively VSTOL aircraft ).

In the meantime, as the F-35 seems a cert', there's still a big question mark over the other aircraft required on CVF; as it seems to me the obvious answer is ' Merlin ', how about a stripped out F-35 to buddy-tank the offensive ones - and maybe even give some short range cover for the fleet...

Please forgive my musings, but this is a 'rumour / discussion network' and I realise all this will have been thought of long before.

'Engines', I have the feeling we've met...

[Ivan Rogov]

Sorry to dissagree LO, but I think E-2 exports have been quite successful

Wiki list 8 (OK 7:E), and I think a couple more countries are interested (Pakistan and somewhere in South America?)

E-2 Hawkeye - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/E-2_Hawkeye#Operators)

[Caspian237]

I'm surprised no one has mentioned the V22 Osprey. Boeing seem to have given up on the idea of placing a large radar on top of the aircraft as it seems there was very little clearance between this and the rotors when in verticle mode. However they are now looking at fitting an inflatable rad dome to the rear ramp. Beedall's site gives this description under a photograph:-

"As an alternative to the Merlin airframe, Boeing is actively promoting a version of the V-22 Osprey fitted with a palletized version of the Thales Cerberus mission system and the Searchwater airborne radar system under the project designation of TOSS".

Third photograph from the top Navy Matters | Maritime Airborne Surveillance and Control (http://navy-matters.beedall.com/masc.htm)

[BEagle]

"As an alternative to the Merlin airframe, Boeing is actively promoting a version of the V-22 Osprey fitted with a palletized version of the Thales Cerberus mission system and the Searchwater airborne radar system under the project designation of TOSS".

Well, at least they've got one thing right....

[wobble2plank]

I also seem to remember, from my dim and distant past, that a friend of mine, ex boss of 820 Merlin Sqn, went to the good 'ole US of A to test fly the Osprey.

His impression was extremely favourable and the info from Thales at the time was that all aircraft lifts were to be made the correct dimensions to take the Osprey. Which has a remarkably small footprint when folded.

Osprey AEW perhaps?

(Sad that the Osprey looks like it's having a dump :confused: At least we had the excuse of rushing the MK2 AEW in for the Falklands, whats Boeings excuse for the jury rig structure?)

[WhiteOvies]

Not to mention the Osprey landing on CVS just to prove a point last year.

Probably discussed before but what would happen if you fitted Carson blades, 5 blade TR and new engines (all proven in SK HC4+) to an ASAC7? Not that we could afford it of course!

[Not_a_boffin]

The bag is actually doing a role more akin to ASTOR / MRA than the original AEW intent - and no bad thing either! However, a significant and important part of the MASC role involves not just AEW, but C2 of offensive force packages, which means better performance than you'll ever get from a pure helo, both in terms of ceiling but more importantly speed and endurance.

Hawkeye can provide the required platform performance, but the mission system performance is reputedly poor and doesn't do the things that the bag does well at the minute.

Sticking the Searchwater on the V22 would go some way towards a compromise between the two extremes, but at what cost? Development, design modification, production of (say) a dozen airframes for the RN and logistic support of same would be far from cheap. Would the current "bag radome" need streamlining to deal with the higher Vmax, and or strengthening the support structure? All allied with an ingenious but fiendishly complex power tx system between the engines that would also have to have generators modded to supply the watts to the mission system.

Nice thought, but unless someone stumps up serious wedge very soon, it ain't going to happen.

[Engines]

A few years ago, Westlands put forward a proposal for a 'compound 101' with stub wings, augmented exhausts and a combined power/flight controls system to provide better speed/height/endurance for an 'AEW/MASC' solution. Anyone know anything more about this one?

In the meantime, Carson blades and uprated engines for the ASACS 7 might very well need to be the stop gap. Just money, right?

The V-22 solution described earlier was designed to be palletized and allow a standard V-22 to take the radar fit fairly quickly, using the ramp aperture to deploy the dome. Not sure that the comms and power requirements wouldn't have led to a special airframe in any case, though.

That said, the Osprey really could offer a very neat solution in terms of speed and endurance. Costly, though.

best Regards as ever,

Engines

[Squirrel 41]

Engines, N-a-B;

As ever, very interesting. The V-22 idea was debated here sometime ago, and IIRC there was also an issue with the lack of pressurisation and, cost. Which was reputedly massive. (Mahoosive, in fact). For a maximum of 12 aircraft, getting the altitude performance and radar integration work done seemed to provide a range of numbers from the shockingly high to the truly absurd. However, if we could expand the customer base, then at least the engineering amortisation would be spread further - which leaves Spain, Italy, Thailand and India as possibles with little carriers and a potential MASC requirement.

(Though I heard a rumour that the Spanish Armada have probably permanently binned their Bagged Sea Kings; sad, if true).

Presume that discussions are on-going with these, and other - USMC? - air arms about a joint programme? This is a rumour site after all....:E

S41

[Jetex Jim]

Before this thread drifts right off the radar, maybe its worth one more bump.

The UK's commitment to STOVL, which ensures high level industry participation in JSF-B, neccesitates a ski-jump carrier. A ski jump carrier, neccesitates a rotary wing 'AEW/MASC' solution. Both STOVL aircraft and rotary wing 'AEW/MASC' will have less capability and be more expensive than non STOVL aircraft and fixed wing 'AEW/MASC'. The new carriers, unlike the RN current boats, are large enough to support CAT/TRAP operations.

STOVL can apparently be justified, though not with any figures in the public domain, on the grounds that STOVL training/currency is much easier than cat trap operations.

Interesting to read, in
Navy Matters | Future Aircraft Carrier Part 12 (http://navy-matters.beedall.com/cvf1-12.htm)
That back at the time of the Phantom/Bucc; cat trap ops were considered no big deal, in fact the 1964 Defence White paper assumed that RAF Phantoms would operate from the carriers too!

At the time, the 'High price help' were arguing the opposite case, in order to support the Spey Phantom, as their succesors are now arguing to justify JSF-B.

Interesting or what?

[John Farley]

Jetex Jim

That back at the time of the Phantom/Bucc; cat trap ops were considered no big deal, in fact the 1964 Defence White paper assumed that RAF Phantoms would operate from the carriers too!

I don't feel that attitudes (and indeed facts) from the past can be used as simply as that to justify actions today.

For example below are the fatalities suffered by the RAF in the early 50s when their only war ops were Sunderlands in Korea. They are therefore effectively peacetime figures. At that time to use your phrase these losses were "no big deal" and certainly coroners and lawyers were not involved.

Year
1950 380 238
1951 490 280
1952 507 318
1953 483 333
1954 452 283
1955 305 182

The first column is aircraft lost and the second total fatalities

I would not expect to argue today that such figures show (for example) the current discussion about a single Nimrod accident is unreasonable. Times really do change and with them people's attitudes and reasons for what they do.

JF

[Simmbob]

Year
1950 380 238
1951 490 280
1952 507 318
1953 483 333
1954 452 283
1955 305 182

The first column is aircraft lost and the second total fatalities

Rather sobering statistics!

[Engines]

JJ,

One more bump then -

The UK has not 'committed to' STOVL - we are still officially in 'wait and see' mode', although STOVL is stated as our 'preferred option' - clear as mud, right? Basically, my view is that we are hedging our bets in case the F-35B falls over big time. My view is that it won't. I might be wrong and others will differ.

Assertions and facts - 'high level industry participation in JSF' is not a direct link to UK buying STOVL. Yes, RR get lift fan work, but they have a good stake in the F136, which could go in all variants. BAES are building bits of all three variants, MB are supplying all the seats.

Cost of F-35B against F-35C, for the same capability, just isn't known with certainty. We do know that C will be the most expensive variant. 'Capability' of a CVF with its air group is not easy to quantify, but there have been studies by respected organizations (actually quoted in the link you provided) that point to very good 'bang per buck' for advanced ASTOVL equipped ships. And one thing is certain - we are going to have less bucks to play with than the USN.

As ever, John Farley is bang on the mark - current requirements for safety and public attention to loss rates would make a move to the very skill intensive world of cat and trap an expensive business (and don't forget the costs of training the deck crews and ships company as well)

This has been a really enjoyable thread,

Best regards

Engines

[Jetex Jim]

Engines
The UK has not 'committed to' STOVL - we are still officially in 'wait and see' mode', although STOVL is stated as our 'preferred option' - clear as mud, right? ...Assertions and facts - 'high level industry participation in JSF' is not a direct link to UK buying STOVL. Well that's clear enough, but the CRS report to congress; dated October 25 2007 puts a rather different slant on it.
http://www.fas.org/sgp/crs/weapons/RL30563.pdf explicitly says
..The costs and complications of pursuing the STOVL variant (including reducing weight growth) are leading some to suggest that the JSF program would be more feasible and more affordable if the F-35B were cancelled. In this case, the Marine Corps would buy the CV JSF instead of the STOVL variant. ...Others point out that cancelling the STOVL version of JSF is complicated by the United Kingdom’s investment in the program and its requirement for a STOVL aircraft...The United Kingdom needs the STOVL design to operate off their aircraft carriers and only plans on purchasing the STOVL design for both their Air Force and Navy. In addition the UK is identified as the only 'Tier 1' participant, with a 2 Billion investment in the project.

JF
Yes indeed, things have changed since the 50s, and a good thing to. However, it would be interesting to see what actual Ark Royal F4 Bucc losses were in the 1970s.

cheers JJ

[airborne_artist]

According to NAVAL-HISTORY.NET (http://www.naval-history.net/) there was only one fatal loss of an embarked (probable) two-seat aircraft from the Ark in the 70s;

Sunday, 3 May 1970

Ark Royal, air crash in English Channel
COOMBES, Phillip J, Lieutenant
STEWART, Alexander, Lieutenant

[Schiller]

Deck landing isn't that difficult (after all, quite a few Crab pilots were taught how to do it), or dangerous, even without intensive practice. During the 60-70's, although the loss rate was high-ish, very few accidents were directly due to carrier landings or launches.

[Brain Potter]

To reduce the shipborne training burden could the routine deck-landing of F-35C be left to automation?

If manual deck-landings were regarded as a reversionary mode then perhaps line pilots would then only practice them in a simulator, with a recurrent dual-check from a small cadre of instructors qualified in live deck-landings.

Pilots are going to have get used to the idea of automatic ejection on the F-35B so perhaps reliance on automatic landings doesn't seem so radical.

[LowObservable]

CV autoland is a huge part of the Navy's X-47B unmanned combat aircraft program, but won't be demonstrated until 2011.

If the program survives, and if it works, the effect on CV aviation is vast. Why so? Because the requirement is that automatic landing should be at least as safe as a piloted landing at all times.

And if the GPS and computers do as well as the pilot on a clear, calm day, they will inevitably do better on a rainy, windy night, because they sense deviations and make corrections at a much higher cycle rate, and because the system uses GPS and neither knows nor cares that it can't see the lights.

It's also a system that is not hard to retrofit to any fly-by-wire airplane.

However, the RN has to make its decision before we know whether it works...

[Jetex Jim]

CV autoland
...if it works, the effect on CV aviation is vast. ...However, the RN has to make its decision before we know whether it works...

Yes, dashed bad timing that.

I keep forgetting that the RN hasn't, officially, decided between Dave B or Dave C yet. Must be that darn Congressional Research Service report, cited above, that insists that the UK has already commited to JSF-B...

[LowObservable]

Right you are, JJ...

All the apparently knowledgeable froods here insist that the UK's position is officially undecided and that there is an exit ramp from STOVL, maintained in place on the far side of STOVL flight testing. As far as I can tell it would mean extending Big Lizzie's phase of Harrier GR9 operations, incorporating cats on Chucky from the get-go, and building cats into the first carrier at the first refit.

On the other hand, the JSF program foams at the mouth at the very suggestion of such treachery, because there is no alternative to Dave B for the Marines. Take away the UK's B order, and the Marine jets start to look very expensive.

[Engines]

LO,

The UK position on STOVL vs. CV is, I absolutely agree, less clear than it could, or should, be. I'd expect a more positive posture soon in response to the JSFPO's request for firm commitments to production numbers.

The UK's B order is important, but the fact is that if it doesn't technically work for the UK, it wouldn't for the USMC. If the UK cancelled for another reason, the USMC would still, in my view, get their Bs. They are absolutely committed to the project, and their track record shows that when they want a piece of kit, they usually get it.

Auto landings - I'll repeat my thoughts. The USN are developing, testing and qualifying F-35C to fit in with their recovery CONOPS, which call for a primary ability to land the thing manually, with JPALS (Joint Precision Approach and Landing System) as a 'recovery aid'. USN is using existing ACLS more than it did before as amount of night flying goes up, but mostly as an aid to glide slope acquisition and initial lineup - I am told almost all landings are still manual to allow pilots to retain their deck proficiency ratings.

In my view, the chances of JSF going to auto-land as a primary recovery mode to the deck are slim. Chances of the USN drawing down on landing training and relying on it are almost nil. If the UK wanted to go against that policy, there would be big money involved.

Still a good thread, this one....

Best regards as ever

Engines

[Mr-AEO]

Engines,

In addition to the ability for an increased bringback which is good, is it also the case that we are avoiding burning a sodding big hole in the deck each time we land (as might be the case from a pure Vertical Landing??).

If so, which one is the real driver for the SRVL?

Also, I don't believe that we can ever 'hand on heart' say that an SRVL is as safe as the purely VL recovery. As has been said, if you hit one wheel on that single oily patch at night, massive brakes or not, you risk 'kerbing' your shiny jet down the flight line or worse if aircraft laden with weapons are involved!

As for bolter, I think that a V22 with a fat tank sat in the circuit would be quite useful for that situation; the rest of the embarked V22 flight could have a radar/mission system and fulfil the MASC role. Not to mention a big space for returning the u/s 'Lightning' powerplants.

[Jetex Jim]

I suppose one could say that regardless of any 'hidden' costs of JSF B, the payback to BAE and RR will still be huge. These companies, thanks to that 2 Billion dollar tier 1 buy in, and what seems to be a commitment to support the case for the STOVL version, come what may, now get to manufacture about 1/3 of all JSF types, at the very least 2000 planes.

So UK armed forces get a couple of big ships, some new aircraft. And maybe they are not exactly optimum but look how much good it does industry! And what's good for BAE and Rolls Royce has got to be good for the UK exchequer – the jobs created, trickle back income tax and other taxes, right ? So stop gripping and just 'Rejoice Rejoice'.

Well maybe. Back in the day, such a deal would have been an unqualified success. Now we have globalised industry and both BAE and RR have production facilities in the USA. RR employ over 8000 people in North America, and BAE 43000. Couple that with the Buy America Act and we have to start wondering just how much of that 1/3 of 2000 will actually get manufactured in the UK?

Well, the UK plans to acquire about 140…

[LowObservable]

I believe that BAE's biggest piece of JSF will be made in USA: the EW system.

[LowObservable]

I too would be surprised if the USN committed to automatic landing for its carrier aircraft, even if the conservatives don't succeed in killing UCAS-D and the program demonstrates autoland successfully.

But it's a pity, because the USN spends a lot of money replacing aircraft that have been flogged to death practicing carrier landings - the lifetime of a Super Hornet seems to be about 17 years, with the type headed for a OSD in 2030 (is that why the export market's not excited?), which doesn't compare too well with the EPAF F-16AMs.

I'd never be too surprised if France, or India, were the first to go autoland for their carrier operations.

[Engines]

Mr-AEO,

The driver for SRVLs is not deck erosion. Deck erosion is an issue, but it's not the reason SRVLs are being looked at. The real reason is the UK desire to get back to the deck carrying more at higher temperatures.

Don't think I ever said that SRVLs will be as safe as a purely VL. I don't know what the relative safety analyses say. Al I do know is that the team will not recommend SRVLs unless they can be made sufficiently safe. Oil on the deck -yes, absolutely a problem. That's why the USN take severe pains to get rid of them ASAP. They are a problem for CVN arrested landings as well.

Best Regards as ever

Engines

[Mr-AEO]

:ok:Engines. Many thanks for the reply.

Noted that we are trying to recover the hot/heavy capability, but is SRVL a critical go/no-go factor in the decision for a STOVL jet (i.e. a Key User Requirement) or have we passed that point already by selecting a certain flavour of CVF? Ipso Facto, we get what we get and if it is able to meet the requirements safely using the SRVL then even better.

[Not_a_boffin]

AIUI, we're not committed yet, but are certainly on the vinegar strokes / got the Jesters toes......

It will probably be too late to get cat n trap into QE before her first refit, but the possibility remains for PoW to enter service fitted for Dave C - particularly given that QE will still be operating GR9 until 2017/2018, which is broadly the IOC for Dave B. Switching to Dave C might knock that back a bit, but ain't a show-stopper yet.

Either way, decision must be made before the end FY at latest.

[VitaminGee]

As ever, very interesting. The V-22 idea was debated here sometime ago, and IIRC there was also an issue with the lack of pressurisation and, cost. Which was reputedly massive. (Mahoosive, in fact). For a maximum of 12 aircraft, getting the altitude performance and radar integration work done seemed to provide a range of numbers from the shockingly high to the truly absurd. However, if we could expand the customer base, then at least the engineering amortisation would be spread further

From aviation week, USMC and TOSS (http://www.aviationweek.com/aw/blogs/defense/index.jsp?plckController=Blog&plckScript=blogScript&plckElementId=blogDe&plckBlogPage=BlogViewPost&plckPostId=Blog%3A27ec4a53-dcc8-42d0-bd3a-01329aef79a7Post%3A6d3e5e72-c23e-4ac3-9bfd-88ff8fda82b5)

...couldn't find mention of this earlier in the thread.

WRT Dave B and SRVLs, is the degree of difficulty increased by Dave B's unconventional flying controls when hovering and the transition thereto?

[Double Zero]

Vitamingee

seems to me you're on a safe bet re. software...

'Engines' will know a lot more about it, but given the basically non-vectoring thrust of the F-35B, it takes a whole new load of software to allow a SRVL.

Why this wasn't an initial requirement still hasn't been explained in words to get into my thick skull, nor has the reason why a ski-ramp isn't of use.

For reference ( of a sort ) we at BAe Dunsfold - no amount of money could seduce talented software guys to the northern slums of Wart On - had a whole, large building especially made housing over 200 people to solely write the control laws for the Eurofighter /Typhoon, they were particularly wary after the first Gripen's disaster ( how the Test pilot survived is still regarded a miracle ).

It would seem the only way the F-35B can slow down is to pitch up, but god knows what the computers make of that !

[NoHoverstop]

Sorry Double Zero but you're a bit off beam.

What makes you think F-35B won't do a ski-jump? Do you think CVF has a bow ramp simply for fun? F-35B most certainly has thrust-vectoring and most certainly uses it.

Many years ago, enlightened souls convinced the MoD to put its hand in the taxpayer's pocket and fund an experimental programme to answer the question "Yeah, but what has active-control-technology ever done for V/STOL?". "Well, there's autostabilisation". "Obviously, but apart from autostabs etc etc". Anyway, the point is that XW175 has tested, ashore and at sea, some pretty fundamentally different ways of doing the V/STOL thing. The option judged to be the best (not by everyone, not without reservations, not without some serious discussions) has been selected as the basis for how F-35B does it. Of the options I've seen (and indeed flown), I happen to agree with that selection. One legacy of all the effort is that UK happens to have pretty much the right tool for the job of actually going to sea and having a look at how something that flies like an F-35B would actually do an SRVL. So we did. Last year on the Charles de Gaulle, with our software tweaked to make XW175 as good a match for the rather heavier F-35B as we could (and if you do ever get to look in XW175's rear cockpit, you'll note it has un-Harrier like things like a sidestick and a whopping-big linear-slidey left-hand "make plane go fast now" control, plus a thing that sayeth "It is now safe to switch off your computer" upon its screen. Verily, I kid you not).

Now I would think that if there were something horrifically wrong with how the F-35B control strategy deals with SRVLs (we did NOT change the strategy from the "Unified" control scheme), we'd have noticed it at some stage in the process of preparing for that activity (or perhaps even in the trial, because if you knew exactly what was going to happen in a flight trial there would be no point going would there? Apart from the food and climate obviously). I might be wrong of course, but "Unified" to me seemed to be pretty much just the job for SRVLs, as of course its originators back in 1980 or so knew it would be (and they'd never heard of SRVLs, but they knew about V/STOL and fundamental pilot-throttley-rudder-stick-stuff and were also a bit clever, which makes the job of those that followed-on, like me, rather easier).

[Double Zero]

Okay Novhoverstop,

You've flown it ( or rather the prototype / simulators ) and I certainly won't; but when I say ' no vectored thrust ' I know that aft nozzle vectors a bit, but not as in the 98.5 degrees - all combined - like the Harrier.

As for ski-ramps, well it seems any decent fighter - as in Mig 29 on the Russian carrier- can do it, but without vectored thrust the launch/ bring back penalty is considerable.

- Yes I've heard at least the first of the CVF's is getting a ramp, but made out to be a hang-over from Harrier times - remind me again about delivery dates & delayed expiry dates ?!

Despite the obvious advantages of STORL / STOVL ( if the kit allows ) the U.S. Marines don't seem to be driving the project along, hence the flat rather than ramped decks of their carriers - they put up with whatever they're given.

[Not_a_boffin]

We're still missing the fundamental problem with SRVL here. FCS is an issue but not a show-stopper. The real problem with SRVL is that once you're committed to touch down, you are totally reliant on the brakes. The throttle will have to be brought to idle, otherwise you're p1ssing away your braking power. If you spool the engine down, there is unlikely to be sufficient time to get sufficient power back on to do anything - that's why boltering is not an issue - if something bad happens you just can't do jack-sh1t about it. I may be missing a trick here and it may be possible to spool up again in the 200m or so between touch-down point and the bow (inc ramp), but then you're into a number of undesirables, like ramp entry speed, a further margin of fuel to allow a (very) abbreviated go-around with consequent impact on the bringback issue that we're trying to fix, and the huge swathe of deck 280m x 18-ish that would then have to be kept clear. Plus, if "something" does go wrong, it is likely to involve lateral forces which will tend to make the cab go anywhere but straight ahead. With VL, the relative velocity is unlikely to make you hit anything, with CV, you're pointed away from the deck park and going so fast that if something does happen you're still unlikely to cause any unpleasantness (except to yourself). SRVL doesn't appear to allow either of those.

Once again, I have no doubt that SRVL can be done - and with a "reasonable" interval between something going wrong. It's just that when the "something" is aboard an operational deck crammed with bombed up, fuelled up aircraft, it might end in tears.

[Question_Answer]

What is the potential for UAV/UCAV operations from CVF?

I assume the maturity of any potential solution is currently so low and that there is no programme geared for CVF which would influence the cats/traps vs STOVL/STORL debate for the long term?

Can CVF (HMS QE) retain the ramp but be fitted with a cat along the angled deck (a la Nimitz class)? Whilst this would give a really good cross deck potential and allow for a mixed fleet (training issues noted!!) I assume that Dave-B and Dave-C are now very different from a logistics footprint (compared to the original intent of JAST to achieve a "common" platform with service variations).

[Not_a_boffin]

You could do it, but why would you want to?

One cat = one point of failure and low launch rate. You could put two in the waist, but it's very cramped. You're also then compromising one of your prime parking positions for STO, in addition to needing the full angle for a CV recovery.

One or t'other. Otherwise you end up like a STOBAR carrier, with a relatively tiny deck park due to the large launch and recovery areas needed.

[Mr-AEO]

N.A.B - nice post, and I quite agree!

Whilst there are obviously no Cat's, does anyone know if CVF are considering a Trap to catch SRVL overshoots? What if the jet has no brakes because of an in-flight emergency? I guess the option there is to dump as much fuel/ordnance as possible and recover light, thereby allowing a STOVL approach?

[Modern Elmo]

Despite the obvious advantages of STORL / STOVL ( if the kit allows ) the U.S. Marines don't seem to be driving the project along, hence the flat rather than ramped decks of their carriers - they put up with whatever they're given.

They'd get a ramp if they wanted one. The ski jump has disadvantages. For one thing, it gets in the way of rotary wing operations.

You've flown it ( or rather the prototype / simulators ) and I certainly won't; but when I say ' no vectored thrust ' I know that aft nozzle vectors a bit, but not as in the 98.5 degrees - all combined - like the Harrier.

For slower, heavier takeoffs and touchdowns, the aft nozzle needs to be able to vector upward to offset the nose down moment due to full[er] flaps.

[Modern Elmo]

Wrong to say slower takeoffs. I should have said "shorter."

How about this?:

SUCCESFUL ESTOL LANDINGS WITH THE X-31A
By Karl Schwarz

„It was the high point of my career as a pilot,“ said Rüdiger Knöpfel of the Bundeswehr Aircraft Test Center (WTD 61) with enthusiasm, as he looked back on the first landing with the X-31A in extremely short take-off and landing (ESTOL) mode. In the critical minutes of the flight he had had virtually nothing to do, as it is only thanks to the unbelievably accurate position finding and automatic control functions of the complex software that the German-American experimental aircraft is able to perform extremely short landings.

...

„You don't have time to be nervous,“ adds Rüdiger Knöpfel, although the manoeuvre is extremely risky. „If the computer reduces the angle of attack too early, the nose landing gear could buckle under; if it acts too late or too little then the tail could hit the ground.“

Neither occurred, a major success for the small test team, which had to contend with a very tight budget. But what was the point of all this expenditure? On the last test flight the landing speed was 121kt (224km/h), down 31% from the normal 175kt (324km/h). Whereas on a normal conventional landing the X-31 requires some 2,400m of runway to come to a halt, all it requires now is 520m.

Such figures naturally depend on the aircraft type, but have the attraction of making landings on short temporary airstrips feasible. The reduction in landing energy is important for aircraft carrier-based operations. The aircraft structure could be lighter or it would be possible to set down with greater fuel reserves remaining or with unused weapons without overstressing the airframe. Again, the requirements regarding headwind on the deck would be less stringent if planes could land at a lower speed.

...

FLUG REVUE July 2003: X-31A demonstrates ESTOL landing (http://www.flug-revue.rotor.com/FRHeft/FRH0307/FR0307f.htm)

http://www.pprune.org/FR0307f1.JPG


http://www.pprune.org/FR0307f1.JPG

[Double Zero]

Modern Elmo,

I certainly wasn't suggesting 'upwards vectoring' though I suppose it would give a specific deck spot to keep clear of !

[Tightflester]

I know that aft nozzle vectors a bit

YouTube - f-35 Thrust Vectoring (http://www.youtube.com/watch?v=iRgcC9eqEJg)

Might help if you define 'a bit'

[Engines]

NoHoverstop's post sets the stall out here, and very well too.

The F-35B can do SRVLs. It's designed to do land based short landings, and the changes needed to get the SRVL optimized for CVF use aren't, I believe, too significant. For those in the programme, the 'unified' control system they have adopted seems to work OK.

The issue Not a Boffin identifies is very real - stopping safely after touch down, or executing a bolter. My view is that a bolter is really a must, and the CVF has the space to adopt an 'angled deck' layout for SRVL recoveries.

One thought on the safety issues - we did takeoffs from the very small CVS for some years, and as far as I know never lost an aircraft or a person to the aircraft running laterally off the very small runway. SRVLs present a similar issue, in controlling a maneuver (in this case decelerating) down a deck. The speeds involved are actually lower for SRVLs. And losing an outrigger tyre would be every bit as bad as losing an F-35B main wheel.

Not trying to be glib, but I trust the team who are working this at Warton and in Fort Worth. They are committed to a safe solution - and I think they'll get there.

Best Regards

[Not_a_boffin]

Engines - the bolter is irrelevant (although missed approach is not). I may be wrong, but would have thought that on touchdown, the engine will be immediately brought to idle (otherwise you're negating your braking effort) which means if something goes wrong on deck, you have no time to spool back up and regain any sort (wing or thrust-borne) of flying speed off an angle. It's been a while since I checked the distances, but assuming a touchdown point 60-80m forward of the round-down, the size of CVF and probable angle gives you around 120m-ish to play with before you hit the deck edge. At 40 knot relative, thats 6 seconds maximum to get back your rpm, probably a bit less if you factor in things going wrong slightly after TD rather than on it, plus an "oh-sh1t" factor and thottle lag. As if thats not bad enough, if you've done any of the hard braking necessary, your actual speed will be WoD plus about 20kts at best.......

An angle should prevent the deck park having a bad day, but I should have thought we're looking at a very wet and scared pilot and a certain requirement for a plane guard (damn - I knew I shouldn't have mentioned that!).

The STO vs RVL comparison isn't necessarily valid - for a kick off, on launch there are minimal vertical loads on the gear compared to a 3-4 degree glideslope and instantaneous frictional contact with the deck on recovery.

I don't doubt Warton & FW are looking very hard for a safe solution - my concern is that they are looking in a very small box from absolute necessity rather than exploring options for "extra" performance.

[Modern Elmo]

Mr. 0^2:

To perform a conventional landing or a short rolling landing or a roll until something stops you landing, one doesn't try to level the aircraft with respect to the surface on final approach. Instead, the nose is pitched up somewhat. The higher the angle of attack on final approach, the less kinetic energy the aircraft's center of mass will have at touchdown, other things being equal. Why? Because both lift and drag increase as aoa of the lifting airfoils increase, until stall.

This is the case whether the aircraft is CTOL or a Harrier or an F-35B.

The point is, one doesn't use thrust vectoring merely to push the aircraft upward or backward, if the goal is a minimum kinetic energy rolling landing. In addition, some thrust vectoring should should be used to rotate the airplane to a higher aoa than could be achieved without thrust vectoring.

The question is, can this attitude control be done without automation?

[LowObservable]

N-a-B...
That would be my view too. And add to that the fact that there is a hell of a lot of rotational inertia in that propulsion system, and it is not going to come to full power like switching on a light.
Another aspect: if SRVLs (as Engines has said) will only be needed on a a Royal Navy Hot Day (as opposed to a Marine hot day, the Marines having the ability to control the weather) with weapons on board, does that mean that everybody (pilots, deck crew) will train for both? Or will SRVL become standard, in order to eliminate double training? And does that affect parking, recovery and sortie rates?

ME...
Good question. In a VL, wing lift doesn't matter - so it's not surprising that the F-35 appears to be designed to land with next to no AoA at the wing. But even at 60 kt (airspeed for a SRVL) that eedy-beedy thin wing is going to need some alpha to produce some lift (I should think). While the integrated controls should handle this, it does mean that the landing will be mains-first, derotate, throttle back, brake...

[Not_a_boffin]

LO

I think if it became SOP then you've negated the reason for doing it in the first place - namely bringback, aka recovery weight. If you plan to do it on a routine basis, you'd have to be a dribbling idiot not to include a fuel margin for a very short go-around, even if that go-around included hitting the emergency ditch everything button (which come to think of it won't be easy with internal weapons carriage). Additional fuel margin = additional recovery weight, which reduces your bring-back etc....

The more you scratch, the less sensible it looks.

[DBTW]

Sorry to come so late to this thread and maybe it's already been raised.

Haven't seen it in my quick scan so I'll just make the point most vertical landings on carriers are made with the ship steaming into wind, so the wind over the deck is often quite high. This means, whilst the piloting technique used is definitely VL, the effect and benefit relative to the stationary planet is that of an RVL. IE any wing lift from wind is always aiding jet lift and therefore potentially increasing bring back loads.

This is particularly noticeable if you compare the Harrier I (less wing lift) approaches to the Harrier II approaches. The big throttle movement during the final transition from wing borne to jet borne flight in a Harrier I happened around 90 knots, whereas it was much later in the approach in a Harrier II. That's why the Harrier II youth used to enjoy the rudder inspection in their early approaches because they missed the throttle up with all the excitement of seeing the pitching/rolling boat!

To my mind, along with deck space issues, creeping and running VLs are avoided in both Harrier models because of weak brakes and slippery flightdecks. There is also the issue of manoeuvring within the 30-120 knot speed range with the Harrier's intake momentum drag stability issues. In a normal ship board VL, where you could be seeing indications of 60 or 70 knots anyway, those problems were avoided simply by keeping the vane straight and the AoA under control. If these problems are overcome then there should be no issue for the replacement jets doing CVLs and RVLs if it helps. It is slightly less flexible because more deck space will get taken up during the landing phase.

Remeber most innovation is brought on due cost. STOVL came about because countries couldn't afford conventional carriers. It could be said that because everybody is so rich now there is no reason why we shouldn't all go back to them. Having lived with both types of carrier though, I believe the desire to return to conventional carriers or "semi" conventional with catapult or arrester gear options really only complicates something that is very simple. And to my mind, innovation is moving forward whereas going back to something is not. STOVL, including CVL and RVL techniques, adds flexibility to the launch/recover options. Adding launch/recover machinery reduces flexibility by making the aircraft more dependant on mum. (IE if the machinery doesn't work the aircraft don't fly/become scrap metal)

Let new aircraft technology close the gap on the perceived (by some) performance benefits of conventional over STOVL aircraft and then move towards shorter runways on land as well.

[Tightflester]

For reference ( of a sort ) we at BAe Dunsfold - no amount of money could seduce talented software guys to the northern slums of Wart On - had a whole, large building especially made housing over 200 people to solely write the control laws for the Eurofighter /Typhoon, they were particularly wary after the first Gripen's disaster ( how the Test pilot survived is still regarded a miracle ).


Where do get this from?
Without going into too much detail (off thread), DASA (as was) accomodated the FJT (Flight Controls Joint Team) out in Munich, there were engineers at Warton, involved in the design, but there certainly wasn't a purpose built building for 200 of them! A number of engineers employed by Warton did work in the software design team out in Germany, but there was only a few and they were not all from the SLUMS as you callously refer to the NW of England.
These engineers were working on Eurofighter flight control s/w a long time before the Grippen incidents and I can't recall anything changing for us as a result of the Grippen incidents.

[LowObservable]

NaB...
True. Not a lot of point in planning a bolter if you've only got enough fuel to get to the impact point.

[Engines]

It's been a while since I was on the programme, and I don't know what the current figures are for the aircraft to go from landing mode to a 'bolter' mode - if that's what they are still looking at.

The distance available down the angle on CVF is about the same as a US CVN (by design), and at the forecast landing weights the F-35B gets off the deck fairly smartly and in a very short distance.

My view remains that to land an aircraft straight down the axis of a flight deck, relying on the (albeit very good) brakes to stop, is not the best way to go. In the final analysis, you are aiming a lot of energy straight where you don't really want it to end up. If you cain aim off, do so, and if you can also bolter, have it as another risk reducer.

Best regards as ever,

Engines

[Modern Elmo]

Remeber most innovation is brought on due cost ...

I assume you mean "cost constraints."

Is that really true, in general?

It sounds like the kind of white lie one tells disgruntled subordinates.

For example, one might argue that the F35-B program itself is an unnecessary extravagance that US air power doesn't need, and that aircraft carriers of any sort should not be Britain's top military priority.

However, others here will reply that I am all wrong and that new STOVL fighter planes on new aircraft carriers are splendid innovations that the UK needs.

I suppose it all depends on who where one's paycheck comes from.

[Modern Elmo]

The throttle will have to be brought to idle, otherwise you're p1ssing away your braking power.

That's a good point. It suggests the additional question, when does the human pilot start closing the throttle in this landing mode?

I suppose thrust vectoring might be used to hold the nose up after touchdown. Is that the case for SRVL landing?

These SRVL landings are planned to happen along the axial centerline of the aviation deck, and not on an angle deck, correct?

In general, is any sort of go-around attempt simply impossible because the F-35B will have insufficient kenetic energy to do so? Unless I've missed a post, the SRVL fellows posting here haven't firmly said yes or no on this point.

[DBTW]

I think the main point about any landing referred to as "vertical" does not have a bolter requirement once you are on the deck. Leaving power up after landing puts you in a dangerous position in terms of contolling a bounce and stopping. As soon as you are down the power comes off and the aircraft is stopped.

The conventional carrier landing technique of powering up on touch down in case you miss a wire does not apply because a landing where the aircraft is mostly jet borne, as distinct to wing borne, needs to have the power completely off on touch down.

Having said that, if you are doing a true VL relative to the deck, I have seen pilots start the descent, not like the picture, re-apply power and pop the aeroplane back up in the hover to reposition. Assuming the SRVL technique being advocated is similar to the Harrier technique, this kind of action will be a little harder to do in a running VL as I think we are assuming the aircraft will be performance limited and using the technique to bring back loads in excess of the normal hover weight. Even so, whilst partially wing borne and partially jet borne in the approach, a pilot using an SRVL technique should be able to initiate a successful go around until just before touchdown.

[DBTW]

Modern elmo. Good point about who pays.