Sea Vixen Fuel Management

[Fonsini]

Apparently at least one pilot managed to flame out both engines on a Sea Vixen due to him failing to "select the right tanks".

I thought that manual fuel management went out with Lindbergh, does the Vixen really require the pilot to manually select tanks, anyone know ?

[ORAC]

Chapter 2, para 4a.......

Sea Vixen FAW Mk 2 Pilots Notes - SeaVixen (http://www.seavixen.org/seavixen-technical-documents/faw-mk2-pilot-notes)

[pulse1]

A very good friend of mine, sadly no longer with us, told me that he only really understood the Vixen fuel system when he became an instructor on the sim. This was after doing a full tour on a carrier.

[Fonsini]

Many thanks as ever Orac, strangely I have Blakes 7 playing in the background as I type this.

Reading those pilot's notes it becomes obvious that the story I recall was caused by the pilot turning off the booster pumps with a resultant flameout when the gravity feed emptied the number 1 tank. Not sure why he would do that though.

Anyhoo, thanks again.

[Pontius Navigator]

There were plenty of other aircraft that could flame out from fuel starvation with tons of fuel remaining, the F4 for one.

[H Peacock]

Jet Provost, albeit not "tons."

Now how on earth can anyone manage to do that?

[Hangarshuffle]

Fonsini
I worked for a Chief who told me that a SV flipped over as it came in to recover onboard a carrier. It inverted rolling left to right and ended up crashing into the sea upside down on the stbd side of the ship adjacent fly 1.
This he maintained was somehow due to an error in fuel tank selection late upon approach.
No idea on any further detail but this would possibly have been on the Eagle, or Victorious.
Terrifyingly adjacent to the deck party, hence him remembering.
This being a tale long remembered but deffo involved fuel tank selection on finals- perhaps someone remembers the full story?

Sea Vixen tales littered my training in the FAA and they must have been horrible to be involved with in cold hard reality they killed a lot of good men.
Off thread, I often think would have been how useful to the FAA if the UK had been involved in Vietnam on the US side, or the 6 day war on either side, or even the Falklands on our side?

[Fonsini]

Fonsini
I worked for a Chief who told me that a SV flipped over as it came in to recover onboard a carrier. It inverted rolling left to right and ended up crashing into the sea upside down on the stbd side of the ship adjacent fly 1.

This he maintained was somehow due to an error in fuel tank selection late upon approach.
No idea on any further detail but this would possibly have been on the Eagle, or Victorious.
Terrifyingly adjacent to the deck party, hence him remembering.

This being a tale long remembered but deffo involved fuel tank selection on finals- perhaps someone remembers the full story?

Sea Vixen tales littered my training in the FAA and they must have been horrible to be involved with in cold hard reality they killed a lot of good men.

Hmm, now I'm confused, so there is an option for tank selection.

Always hate to hear about those crashes even when there is something to be learned from them. I can't think of a more terrifying job than sitting in the "coal hole" of a Sea Vixen during a carrier landing.

[Madbob]

H.Peacock

Try inverted flight or even a bit of zero g mixed with a bit of negative when trying to wring the best you think you can from the JP's limited performance:🤔
Leave the throttle wide open (one doesn't have a lot of choice here!) and wait 30 seconds and you will find out!:😳😳
MB

[H Peacock]

Try inverted flight or even a bit of zero g mixed with a bit of negative when trying to wring the best you think you can from the JP's limited performance:��


Ah, I see. Zero/negative g v recuperator capacity. I thought you were referring to fuel mismanagement, ie pumps and tanks!

[pulse1]

I have just been reminded that I once had a Sea Vixen parked outside my office while they worked out how to convert it for pilotless flight. My previously mentioned good friend told me that he thought that the fuel system was far too complicated to be operated remotely. However, as far as I know, they did successfully use the Vixen to replace the Meteors so they must have been able to do it.

[Mechta]

However, as far as I know, they did successfully use the Vixen to replace the Meteors so they must have been able to do it.

I have yet to find a reference which confirms unmanned operation of the Sea Vixen when converted to the D.3 Drone. Evidently they could be controlled from the ground but it would appear that a standby pilot was onboard (to operate the fuel system?).

Targeting at Llanbedr (http://www.airsceneuk.org.uk/hangar/1999/dera/targets.htm)

Between 1977 and 1985 the aircraft was converted to a D.3 drone by Flight Refuelling Ltd and flew as a manned drone from Llanbedr from 1986 until its retirement in 1991.

Sea Vixen Drone (D3) Era - SeaVixen (http://www.seavixen.org/sea-vixen-drone-d3-era)

3. Testing. All the test flights during the development took place with a pilot in place but he was able to fully mimic the intended remote control as a push-button matrix was installed at eye level. So all the commands available to the ground operator could be produced by the pilot, ie bank left, bank right, climb, descend, throttles open, undercarriage up / down etc. After the early flights the test pilot was able to completely fly the aircraft from take-off to touch-down using the push-buttons (around 20 if I recall correctly) with the new drone avionics turning the simple button pushes into control surface and throttle movements.

[megan]

Hangarshuffle, reading through the accident listings the only one that mentions fuel transfer problems on a deck landing is XJ853 of 892 Squadron on HMS VICTORIOUS 8th February 1961. Fuel failed to transfer from starboard drop tank and on landing the overload from the full tank caused the oleo on that side to collapse. A number of other aircraft are mentioned lost due to transfer problems, but not in the vicinity of the carrier.

One hell of a loss rate, 54 airframes of the 145 built, not including both development prototypes lost, making 56/147.

http://www.seavixen.org/images/templates/articlephotos/1_892_prang.jpghttp://www.seavixen.org/images/templates/articlephotos/3_892_prang.jpg

[Lordflasheart]

Fon - you didn’t identify the particular accident, but you indicate there may have been a simple cause …. I don’t think there was anything simple about the Vixen.

I didn’t fly the Vixen but I was around when they were. ISTR one of the early problem areas we heard about, was if you had a double generator failure. This could be brought about inter alia by low level high IAS occasionally causing a belly panel to detach along with necessary electric bits. The catch was you then had about 20 minutes flight remaining before the batteries failed. When that happened there was nothing left to push the fuel to the engines so not a lot to prevent a double flameout through fuel starvation, and not a lot you could do about it. I don’t think this precise situation had been anticipated during development so it was a bit of a surprise to the squadron boys when it first happened on the Mk 1. I assume remedial modifications were quickly put in place, to mitigate the immediate problem, including for the Mk 2. The Ram Air Turbine only provided hydraulic power. I wonder if they ever considered it for electrical generation.

Moving on from ORAC’s link to the Vixen Mk 2 PNs dated 1970, and for lack of any more specific answer (so far) to your question, here’s a most succinct quote from the same seavixen.org website, by the famous Jon Whaley, who is still current on type -

“Fuel management was one of the Vixen's highest workload for the crew. There are FOURTEEN tanks if you were carrying two drops, a total of 13,500 lbs or 7,670Lts. You had two fuel gauges, one for each side. You or normally the Obs could cycle the gauges to show the contents or sum of tanks 1 - 4. The fuel in the Pinion tanks and Drop tanks was not gauged. (The Pinion tanks were only on the Mk2 being extensions to the Mk1's booms in which fuel could be kept). Air pressure from the engines pushed the fuel from the drops into the No 2 & 3 tanks. To pump all this about, there are 10 main Booster Pumps and 6 auxiliary pumps. If I tell you that the P/Ns have 16 pages on the fuel system, you'll understand why I don't go into much detail. Fuel management was critical.”

‘Nuff said ? ..... LFH

ps One hell of a loss rate, 54 airframes of the 145 built, not including both development prototypes lost, making 56/147.
.............. including well over 50 aircrew.



......................

[ORAC]

I didn’t fly the Vixen but I was around when they were. ISTR one of the early problem areas we heard about, was if you had a double generator failure. This could be brought about inter alia by low level high IAS occasionally causing a belly panel to detach along with necessary electric bits. The catch was you then had about 20 minutes flight remaining before the batteries failed. When that happened there was nothing left to push the fuel to the engines so not a lot to prevent a double flameout through fuel starvation Sounds like an improvement on the Tornado F3......

[LTCTerry]

Not Sea Vixen, but about unusable (unreachable?) fuel.


My dad was leading a group of F-4s from Viet Nam to California for depot-level maintenance. One of the guys ejected over the Pacific after fuel starvation despite a full drop tank.


From what my dad told me, they were always supposed to burn off the center line drop tank first as it used bleed air instead of a pump to move fuel up. If you waited too long, ice could form and block the fuel line. No fuel. No thrust. In a Phantom that means the glide ratio of a rock.
At least they had plenty of time to radio for SAR to come get him.


Side note - the fuel system for the Sea Vixen sounds like a nightmare.

[walbut]

Mechta,

I believe you are right in thinking that the Sea Vixen drones never flew without a pilot on board. I worked on the project at Brough in the 1970's, as we were at that time the Sea Vixen design authority as part of Hawker Siddeley Aviation. I assume that was because were were also design authority for Buccaneer and Phantom, so must know something about carrier borne aircraft. The drone control pack that sat in the cockpit in the observers station was known locally as 'the iron man' I made several trips down to Tarrant Rushton airfield to liaise with Flight Refuelling who were doing the majority of the design work. I can remember watching one of the aircraft weave its way down the runway under the control of the ground operator.
There was considerable debate about the safety of the system fitted and what was the preferred method of destroying the aircraft if control was lost. There were a number of explosively driven actuators that put in full aileron, elevator and rudder control deflections, independently of the main drone actuators. I seem to remember the plan to minimise the potential cone of impact was for the aircraft to be pitched up into a spin rather than pitched down into a spiral dive.
I don't know why the project never came to fruition but I believe there was some concern about the extent of corrosion in the airframes and there was a possibility of the aircraft breaking up under the loading of the planned evade manoeuvre that the aircraft was to perform when approached by the missile being used against it.
Like a lot of MoD sponsored projects at the time it just seemed to drift along with no clear end in sight and then faded away with no feedback why. Then again maybe I was in such a lowly position in the organisation in those days the management never told me such things.

Walbut

[Fonsini]

Fon - you didn’t identify the particular accident, but you indicate there may have been a simple cause …. I don’t think there was anything simple about the Vixen.

Moving on from ORAC’s link to the Vixen Mk 2 PNs dated 1970, and for lack of any more specific answer (so far) to your question, here’s a most succinct quote from the same seavixen.org website, by the famous Jon Whaley, who is still current on type -

“Fuel management was one of the Vixen's highest workload for the crew. There are FOURTEEN tanks if you were carrying two drops, a total of 13,500 lbs or 7,670Lts.

Here is what I recall of the "incident". It was a 4 ship on bombing practice, our man was tootling along quite happily in the slot position when suddenly there was a double flameout accompanied by all the bangs associated with disrupted airflow in the inlets. The Vixen dropped out of formation and began to lose altitude, the Obs commented that the pilot's hands were suddenly a complete blur as he began switching tanks and throwing switches to find some fuel, eventually succeeding and performing an air restart. In the debrief the Boss chided him for poor formation flying. The fuel mis-management and flameouts were never mentioned by the aircrew as I assume this would have resulted in a write-up of some kind.

[safetypee]

Following a brief and exciting association with the Sea Vixen, I concluded that it was an aircraft where the adage "if I can start it, I can fly it" did not apply. The parking brake being the problem.
Any flight without a fuel pump failure was a success. (was it 10 switches on the gang bar to get them on, but not so many to turn off after flight, and nearly as many white 'dolls eyes')
The inboard engine would flame out at high altitude with any slight disturbance; I didn't know that, so back to re read the pilots notes - a short two line entry explained the problem (pt 3, 2, c).

Then there was mod xxx, which enabled the approach speed to be reduced by 5 kts; wow what great aerodynamic achievement was this. None could be found on the airframe, but the small print in the tech log explained that if the bubble canopy was fitted then with a higher seat position the speed could be reduced.
Transonic flying was always full of surprises; the control system changed gear. A slight wing drop approaching M1.0 (pilots notes) was invariably a roll through 180deg followed by a supersonic recovery.

A few years later I was able to exchange experiences with one of the DH test pilots. After several beers we concluded that the difference in our views was due to the intervening years and experience; his stopped with the Vixen, mine started with the Lightning.
The Sea Vixen was a very good aircraft for its time, and in latter years enabled me to enjoy a rewarding love-hate relationship. Sadly my aircraft had to go to the drone factory.

[walbut]

I believe one of the reasons the Buccaneer fuel system was originally designed to have no electric pumps was because the Navy had such poor experience with the Sea Vixen multi pump system. Two were eventually introduced to transfer the bomb door tank fuel but as far as I can remember they were reasonably reliable.

Walbut

[4Greens]

The loss rate from the Scimitar was worse than a Vixen. Around fifty per cent of aircraft built. It was a simpler aircraft to fly than a Vixen. Maybe having somone in the coal hole helped.

[Hangarshuffle]

There was a really good article about Fuel Management of the FAW1 Sea Vixen in the FAAs "Cockpit" magazine many years ago by I think the now late Graham Wilcock as I recall (from the FAA museum I think, not sure), that is worth a read. In fact it really struck me at the time reading it - they launched from around Malta at Xmas time on the back end of a Far East deploy- nearly ran out of fuel recovering to 04 Yeovilton (at the end that is think - he was trying to recover to 27 and went into the circuit left hand then onto 04-Winter and weekend and marginal weather). Tanks practically dry as they rolled out.....worth a read if you can find it.

[Bengo]

The Vixen was still made for pitch-up. (Bah bah doop bah bah doop).

It also needed, and eventually got, a step change in the FAA's approach to what is called today a CAMO. Any one remember "We have a Problem"
M

[keith williams]

The Sea Vixen accident record was not good, but was by no means exceptional for that period. The following figures have been copied from the "Meteor Research" Thread. They include only accidents for the Meteor aircraft.

1. 150 total losses in 1952
2. 68 lost after running out of fuel
3. 23 lost doing official low level aeros displays
4. 890 lost in total
5. 436 fatal accidents between 1944 and 1986.

[Fonsini]

I still think that every Sea Vixen Observer deserved a DFC.

I wonder if we have any as members ?

[Rossian]

.....I think I know of a NornIrn one not too far from here. Did the exchange IIRC.

The Ancient Mariner

[walbut]

Towards the end of its service life, the original Sea Vixen drawings were kept in a small store room at the end of the main drawing office at Brough. Some of the original drawings were by then, pretty tatty, but some had been traced and were beautifully drawn in ink on linen. There was one particular drawing of the engine driven accessory gearbox that was absolutely fantastic, every nut, bolt, washer, split pin and spline fully detailed.

I resolved that just before the drawings were going to be disposed of, I would borrow that particular one and have it framed on my living room wall. Alas I missed my chance, the next time I visited the store room they had all gone, presumably to a museum somewhere. Perhaps they are now kept by the de Havilland museum in London Colney?

[GeeRam]

Old chum completed time in Fleet Air Arm as Sea Vixen 'looker,' and promptly changed colour to become WIWOL

I seem to recall that one of the two pilots that made the very last ever RAF Lightning flight delivering 2 x F.6's to Cranfield in 1988 had previously done an exchange tour with the FAA flying the Sea Vixen.

[Pontius Navigator]

LTCTerry, IIRC it was any fuel not in the fuselage at risk. Tanks certainly but also wings if the fuel burn exceeded the wing transfer rate.

[tarantonight]

My father was a driver and I am still in touch with a couple of his Lookers (absolute top men, both of them without a doubt).

I went flying with a mate of mine many years ago who at the time was in the AAR World. To cut a long story short, I learned then that whatever you do is another day at the office.

Having said that, on finals to Ark Royal at 0300 in the South China Sea during a storm from hell..........

[glad rag]

Great thread, reading the Pilots notes alongside the remarks here are a REAL eye opener.

[Fonsini]

Surely we have at least one Vixen looker hereabouts - anyone ?

[MPN11]

Any discussion of the Sea Vixen reminds me of a mate from BRNC who found himself approaching terrain at low level. His O didn't apparently hear the 'Eject" call.

It was sobering at SBAC a few years after I had gone light blue to encounter some old BRNC mates in the FAA enclosure, and discover how many had not made the reunion. They were hard days, whatever uniform you wore.

[Wander00]

I recall in the early days of 360 the odd part at a FAA mates house, and the conversation always turned to accidents various, usually fatal. The RN wives seemed to take it in their stride, but RAF wives tended to go a bit pale.

[pulse1]

Having lost 6 close friends out of total of 22 during his first carrier tour, my old friend said that he would buy himself out if he had to do another. He did do a second tour and they lost no-one so something must have improved.

[SpazSinbad]

'pulse1' said:
"Having lost 6 close friends out of total of 22 during his first carrier tour, my old friend said that he would buy himself out if he had to do another. He did do a second tour and they lost no-one so something must have improved."
I can only guess that from research about 'how others deck landed' that the re-introduction of LSOs to help ameliorate the loss of Sea Vixens and crews perhaps was a factor. Of course there are many other factors as outlined/hinted at in this thread.
“...This large aircraft [Sea Vixen] was operated from small aircraft carriers by day and night. It was difficult to deck land because being an aerodynamically clean aircraft it had low profile drag. The consequence of this was that the throttles were retarded to about one third of their travel in order to command the low thrust required for a constant speed approach critical for deck landing. The engines were therefore operating in the lower rpm response time margins when fully configured on approach to land. Speed control was difficult and speed accuracy was essential to the safe conduct of a deck landing....”

http://www.seavixen.org/sea-vixen-accidents-public-page
FLY NAVY - The view from the cockpit 1945-2000 - Lieutenant Commander Bob McQueen, Commanding Officer, 899 Squadron, Sea Vixens, HMS Eagle, 1966. RNAS Yeovilton, 1968
-
“In the course of my 700-odd fixed-wing carrier landings in the comparatively safe environment of the angled deck, several refinements were introduced to improve the art of deck-landing and make it safer.

One was the 'Donkey's Tail', a vertical string of lights dropped down over the ship's stern to extend the very short line of lights indicating the deck centreline. For the pilot on approach at night its effect was magical, for the slightest deviation from the true centreline immediately showed up as a kink in the donkey's tail, allowing much more precise line-up control than before; and as a Sea Vixen landing at 130 knots on one of the smaller carriers like Centaur or Hermes could not be more than two feet off-centre without the risk of hitting something, this was important.

Even more momentous was the introduction of the LSO or Landing Safety Officer, previously the 'batsman', who had been pronounced redundant with the introduction of the mirror landing sight. Initial problems with the big fast jets forced a re-think on this and the LSO reappeared in the form of a senior pilot, of such experience that even I as a Squadron C.O. could not question his judgement, monitoring all landings from the deck-edge with the power to 'wave off' any dubious approaches. And because his assessment of each landing was posted up in stark colour on a board in that most public of places, the Squadron briefing-room - red for dangerous; yellow, passable; green, good; and green star, teacher's pet - deck-landing became competitive. The LSO, stalking the crewrooms with his clipboard preaching the one true faith, standardization, was at first resented by some of us more senior and experienced pilots, but there was no escaping the very public verdict of 'The Board', or the fact that deck-landing safety improved tremendously, to the extent that most pilots including myself were soon catching the target No.3 wire on the centreline every time. Dare one say - a little tame?

However, other things could happen to spoil a pretty row of 'greens'. [OK landings as shown on a 'greenie board']”
[SEA VIXEN] Lt. Cdr. (P) John E. Kelly. RN.“...6/1/1961 he witnessed Accident ID 4. From his Interview:

http://www.seavixen.org/aircrew-testimonies/testimonies-john-kelly

"The C.O. Dave Stanley and myself as No2, followed by a second pair Lt. Cdr. Jeff Varley and Lt Dudgeon set off for night touch and go DLP. On completion of my 4 night DLP's and Hook On, I went to Flyco to witness the second pair. On the final (4th) night approach Lt Dudgeon was authorised for "Hook Down". There was no LSO in those days. The approached seemed a little unsettled and Lt Dudgeon self waved off. His port wing tip struck an engine box parked in Fly 4. A six foot section of his port wing separated and the aircraft continued inverted down the flight deck and crashed into the sea. His previous approaches had been perfect. Lt Dugeon was a highly skilled and experienced night deck lander from the Sea Venom days. Jeff Varley who had just landed on and was walking back to the Island also witnessed this sad occassion....”
Personal Testimony of Sea Vixen Operations by: Lt. (P) Jonathon Whaley. RN. 1965/1973

http://www.seavixen.org/aircrew-testimonies/testimonies-jonathan-whaley

“Am I qualified to write a "Pilots Perspective" on the Sea Vixen? Well as probably the only pilot left that still flies a jet fighter www.heritageaviation.com and who flew Sea Vixens operationally for two tours, one as Air Warfare Instructor (AWI), I stake my claim.

I'm allowing myself (or I hope the Ed. will) a paragraph of "Soap Box" One of the primary requirements for acceptance in to the Royal Navy and in particular as Naval Aircrew, is to have a sense of humour. The source of "If you can't take a joke, you shouldn't have joined" the Senior Service. If your sense of humour was slightly warped, then a) you were a survivor by nature and b) destined for great things.

The Fleet Air Arm, at the time I joined in 1965, were losing about 1½ aircrew a year per squadron. That's three killed out of 28 Pilots and Observers. You gotta have a sense of humour just to want to join! Circa 1971 "SOPs" were tightened up and "job's worth" criteria added to restrict the antics of aircrew such that losses were dramatically reduced. In 1969 when we lost a couple of Vixens flying in to the sea at night, the papers never mentioned it. To day, such rare accidents are front page news. I'm not saying today's restrictions in flight ops are wrong in any way, just that I was lucky enough to fly (and survive) in the last few years....”

[peterperfect]

ORAC, fascinating reading the Sea Vixen Pilot's Notes you provided the link to earlier.

Slightly off thread but is raises the question who was L. T. Dunnett ? His signature is on the first paper page of the notes in the ring binder.
I did a quick 'google' and he also released other Manuals: Seamanship and Mathematics etc.
I recall that JSP 318 as late as the mid 1980s had his signature too.

What was L T Dunnett's position in MOD PE ? Is he (or she) still alive and has a tale to tell about the responsibility of releasing all these important documents ?

[Innominate]

I suspect that Dunnett was a senior civil servant who may not have been closely involved with the editing etc. of such manuals. In the inter-war years Air Publications carried the name of (I think) the Secretary of State for Air who would have issued instructions that APs were to be published, but probably didn't see even the final proofs.

Sir (Ludovic) James Dunnett was Permanent Under-Secretary at the MOD from 1966 to 1974 http://www.gulabin.com/britishcivilservants/pdf/Senior%20Civil%20Servants.pdf

[jimjim1]

I thought that manual fuel management went out with Lindbergh, does the Vixen really require the pilot to manually select tanks, anyone know ?

Well no (you are thinking incorrectly:-) - e.g. look up the Clutha Bar Police helicopter crash only the other year.

https://www.gov.uk/aaib-reports/aircraft-accident-report-aar-3-2015-g-spao-29-november-2013
Has a summary.


https://assets.publishing.service.gov.uk/media/5628ea4ded915d101e000008/3-2015_G-SPAO.pdf
Full report.


From memory:- Helicopter with fuel on board and with no evidence of fuel supply system faults (pumps or valves or pipes) fatally crashed due to the engines not being supplied with fuel.

Switchology issue?

Possible issues with some of the 4 fuel level sensors?

Jim.

[Engines]

Perhaps I could offer a couple of thoughts.

Military aircraft fuel systems are complex and are getting more so. In my view, this is probably linked to the need for LO airframes, where more fuel has to be packed inside the mould line inside of dangling off the outside in a drop tank or two. As a result, fuel has to be spread around a number of tanks scattered around the airframe. On top of that, the aircraft C of G has to be maintained to close limits (this has always an issue for single rotor helicopters) and even required to help with cooling the aircraft. Add in AAR capability plus redundancy features and you have some seriously complex plumbing.

Harrier had some fairly challenging fuel system architecture to maintain fore and aft C of G, as well as some definitely 1960s type indication and control systems. Plus the UK's insistence on playing around with the way the indication systems worked. That led to the loss of at least two T12s due to pumps being selected off and not switched back on.

The RN had some issues with fuel management on Sea King Mk5, caused (as I remember it) by a substantial aft shift in C of G. Again, some fairly critical pumps had to be switched on and off at various times.

My view only, but any fuel system that needs to be actively managed by a single pilot is an aircraft loss waiting to happen. With two (or more) aircrew, the risk is reduced, but certainly not avoided. Similarly with fuel jettison systems that can be switched on and not always switched off. This is not always a recognised risk. It needs to be.

When the UK fitted RTM322s to Apache, I attended a CDR where we were told that the (really quite good) automatic fuel management system on the aircraft would have to be 'overridden' and 'actively managed' to cope with the much heavier engines aft of the C of G, as it would cost too much to change to software handling the management system. This was agreed to there and then by the then PM. Not a few of us in the audience disagreed. I'd be interested to know whether this caused any issues in service.

The F-35 has a complex fuel system, doing lots of stuff around the airframe. The head of the team designing it was Brit, very experienced and able to use all the lessons learned on Typhoon. He was very well regarded at Fort Worth, but he had to handle literally hundreds of charges to the system. His view was that the fuel system is frequently called upon to help solve problems all over the airframe. That can lead to complex results.

Best wishes as ever to all those poring over fuel system diagrams,

Engines

[yossarianabu]

The Sea Vixen fuel system was, indeed, a nightmare. We often shut down one engine on LLCAP and I spent more time (as a Looker) managing the fuel system than I spent looking for bad guys on the radar. It was even worse if you drew the short straw and ended up flying the Vixen tanker from the deck. Unlike many Lookers, I survived and moved on to F4's but I'm still waiting for my DFC!!

[Geriaviator]

This Sea Vixen thread brings happy memories from 45 years ago when I and my Tiger Moth (pic below) were very privileged to be guests of the Royal Naval Aircraft Yard, Sydenham. The skipper, Captain Monk, had instructed on TMs during the war and it was a treat to fly with him. We flew from the Naval officers' golf course alongside the tower and nobody seemed to mind the tailskid furrows along the turf -- or they were too polite to mention them.

The Yard had its own Vixen which carried the Red Hand of Ulster on its fins and (all this is from memory) was flown solo on occasion. Then came an edict that Sea Vixens required a permanent Looker because the pilot could not access all controls. I think this included some aspect of fuel management. While pilots were on hand at the Yard, Lookers came and went, so it was agreed that a civilian Looker could be trained to fill in when necessary.

The lucky (?) man was my friend Ivan, a radar techie who was familiar with the beast's electronic innards. So the Yard's Sea Vixen, always polished to perfection, was adorned with the names of the Lt/Cdr (Air) Tom Tuke on one side, and Mr Ivan Mawhinney on the other. I tried Ivan's Coal-Hole and did not fancy it one bit, although the Looker's seat in the nose of the PR9 Canberra proved even worse.

Incidentally, Sea Vixen nose 125 at IWM Duxford was flown there from Sydenham, the remaining machines being broken up. After takeoff 125's gear would not retract so it was decided to leave it down rather than risk the obvious problem. Just thought I would mention this in case anyone fancies giving 125 an airing someday :eek:

https://s20.postimg.org/x1x297sx9/TM_sydenham.jpg

[steamchicken]

So what was with the manned drone thing, then? Were they using the aircraft as a testbed for the drone electronics?

[walbut]

Steamchicken,

The intention was to use the Sea Vixens retired from FAA service as realistic targets to evaluate the effectiveness of various anti aircraft missiles. The drone control pack fitted in place of the observers seat. There were a number of electrical actuators distributed around the aircraft to operate the flight and engine controls, together with an independent system to destroy the aircraft if control was lost when flown as a drone.

To allow the drone control system to be developed, the aircraft could be flown with a safety pilot who could monitor its performance and take over control and land it if the drone system failed. In principle it was a similar system to that recently retired on the USAF F4 Phantoms.

Walbut

[steamchicken]

Steamchicken,

The intention was to use the Sea Vixens retired from FAA service as realistic targets to evaluate the effectiveness of various anti aircraft missiles. The drone control pack fitted in place of the observers seat. There were a number of electrical actuators distributed around the aircraft to operate the flight and engine controls, together with an independent system to destroy the aircraft if control was lost when flown as a drone.

To allow the drone control system to be developed, the aircraft could be flown with a safety pilot who could monitor its performance and take over control and land it if the drone system failed. In principle it was a similar system to that recently retired on the USAF F4 Phantoms.

Walbut

Thanks, this makes more sense than the Monty Python-ish idea of a manned unmanned aerial vehicle:-)

[megan]

The currently flying SV is one of the ex drones.

[Lordflasheart]

But was it ever allowed to go solo ?

[Bonkey]

I have just been reminded that I once had a Sea Vixen parked outside my office while they worked out how to convert it for pilotless flight. My previously mentioned good friend told me that he thought that the fuel system was far too complicated to be operated remotely. However, as far as I know, they did successfully use the Vixen to replace the Meteors so they must have been able to do it.

So did I have one (actually two) Vixen's parked outside of my office awaiting conversion to drone. Did you work for Flight Refuelling by any chance as this was the company tasked with the D3 conversion? However the program was cancelled before completion and the Sea Vixen never flew pilotless, always had a safety pilot on board whether being trialed from Hurn or Llanbedr.

[Bonkey]

The currently flying SV is one of the ex drones.

Indeed it is, XP924 was the back-up / second development aircraft. XN657 was the main airframe used for trials and had the code "TR1" for Tarrant Rushton 1 on the nosecone. It's call sign was "Rushton 1" when communicating with the development team once airborne.

[Bonkey]

Mechta,

I believe you are right in thinking that the Sea Vixen drones never flew without a pilot on board. I worked on the project at Brough in the 1970's, as we were at that time the Sea Vixen design authority as part of Hawker Siddeley Aviation. I assume that was because were were also design authority for Buccaneer and Phantom, so must know something about carrier borne aircraft. The drone control pack that sat in the cockpit in the observers station was known locally as 'the iron man' I made several trips down to Tarrant Rushton airfield to liaise with Flight Refuelling who were doing the majority of the design work. I can remember watching one of the aircraft weave its way down the runway under the control of the ground operator.
There was considerable debate about the safety of the system fitted and what was the preferred method of destroying the aircraft if control was lost. There were a number of explosively driven actuators that put in full aileron, elevator and rudder control deflections, independently of the main drone actuators. I seem to remember the plan to minimise the potential cone of impact was for the aircraft to be pitched up into a spin rather than pitched down into a spiral dive.
I don't know why the project never came to fruition but I believe there was some concern about the extent of corrosion in the airframes and there was a possibility of the aircraft breaking up under the loading of the planned evade manoeuvre that the aircraft was to perform when approached by the missile being used against it.
Like a lot of MoD sponsored projects at the time it just seemed to drift along with no clear end in sight and then faded away with no feedback why. Then again maybe I was in such a lowly position in the organisation in those days the management never told me such things.

Walbut

Correct - the Sea Vixen drone never flew without a safety pilot on board. The corrosion was fine on the airframes allocated for D3 conversion as they were specifically selected after thorough inspection by FR and engineers from the FAA and Farnborough and many were from the fleet based at VL - some had never even been on a carrier. Quite a few were from 899 squadron too when Eagle was decommissioned - but the corrosion was perfectly OK. In fact many frames were relatively young and quite a few were from the "XS" serial range built in the mid-60s so were only about 7-8 years old when taken out of naval service. Two came from the School of Aircraft Handling at Culdrose and were flown up on a one-flight test certificate after some 10 years outside and these were a bit ropey - it was these two were parked right outside my office window.

The project ran for about 10 years from 1974 until cancellation and the main reason I believe for cancellation was that AAM seeker technology (and emerging computer simulation) had progressed so much that it obsoleted the need for full-scale target drones. During the development we did get to the stage of flying the aircraft out of Hurn Airport (BOH) from take-off to touchdown fully remotely, albeit with a safety pilot on board. Not sure that sort of work would be permitted from BOH now!

FR also used two of the airframes allocated for drone conversion for other purposes - XJ524 was used as a high-speed target tug for the navy with the low-level height keeper target towed behind to simulate a low-level incoming missile such as Exocet. That aircraft was pretty busy after mid-1982!! A second frame (XJ580) was used for the flight trials of the new Mk32 underwing refuelling pod then being developed for the upcoming VC10 tanker fleet. This frame was alternately based at BOH and Boscombe Down and flown by an FR pilot and a civilian in the coal hole and trial refuelled a number of aircraft from Boscombe including the Phantom, Buccaneer, Lightning etc. Happy days working there,

[pulse1]

Bonkey, I did indeed work for Flight Refuelling Electronics. Although we had nothing to do with the Sea Vixen venture itself we did provide a service by vacuum heat treating various manufactured parts for them.

[Bonkey]

Bonkey, I did indeed work for Flight Refuelling Electronics. Although we had nothing to do with the Sea Vixen venture itself we did provide a service by vacuum heat treating various manufactured parts for them.

Ah ok, the Sea Vixen outside your office must have been that FAW1 version that was based at the Wimborne factory? If I recall correctly, it was about half-way up the Wimborne site between where the fitting shop ended and the FRE buildings started? You probably recall some of the folks I worked with at FRE for a while....Dave Plowman, Brian Nurthen, Alan Hearne, Jack Dillon-Lee. There were more....but is nearly 40 years ago now!

[NickB]

A friend of mine was a FJ Observer in the RN who trained on the SV but then moved on to the mighty F4 on 767 NAS.
Lovely chap, but he wasn't a fan of the SV - I'm sure he said he spent most of his time on SVs managing the fuel!
Very dangerous times - in his words, if you were going to meet your maker, it would be when deck landing at night! Can't even begin to imagine what that must have been like strapped into the 'coal hole' of a Sea Vixen... :\
Brave chaps.