Sea Vixen PR2a

[lenny100]

Sea Vixen PR2a

Following humiliation at the 1956 Suez crisis when they had to rely on the RAF with its new Meteor PR19 aircraft for high level photo reconnaissance  over flights to find targets in the southern Egypt area of operations, the lords of the admiralty requested funds for a new purpose built high flying reconance aircraft to operate from a carrier deck.
These funds were refused but a small allocation was given to upgrade the a current platform. so they issue the 1958 photo  reconnaissance operational equipment  specifications for a aircraft using a current airframe but capable of flying at +65,000 feet for 2,500 miles unrefueled, and landing on a carrier with a deck with of max wingspan of 75 feet.

Two company's responded

Blackburn with a variant of the new Buccaneer navel strike aircraft whose bombay could already carry  a photo-reconnaissance "crate".
This reconnaissance package featured an assortment of six cameras, each at different angles or having different imaging properties, but this could only be mounted on missions specifically involving reconnaissance activities, as it removed most of weapon carrying capability of the aircraft, and the service ceiling was only 40,000 feet so they suggested a dedicated type using up-rated engines and a dedicated photo-reconnaissance package with a ten foot wing tip extension bringing the wingspan to 54 feet.

De Havilland suggested a variant of its Sea Vixen aircraft, a twin-engined all-weather fighter which was in full service with the fleet, with a photo package using 3 up to cameras in the nose of the aircraft and a package of two further aft, behind the crew compartment, up rated engines  and a  new larger outer wing section with a stretch of 10 feet bringing its wingspan to 74 feet the maximum possible to allow it to land on the current large fleet carriers with a option to fit a even  larger outer wing for the projected CVA-01 aircraft carriers. 

De Havilland's design was seen as a better overall package and a order of 3 development and test aircraft were ordered.
The aircraft shared the company's very successful twin-boom layout of the de Havilland Vampire aircraft, but unlike the wooden body of the former it featured an all-metal structure and also swept wings.
It was to be powered by two Rolls-Royce Avon 210 engines with 13,000 lbf each.
The first prototype PR Sea Vixen was built using company's second dh101 prototype which was still in storage after it finished trial flying in 1960 in support of the Sea Vixen FAW1 program, with the new engines and improved navigation systems fitted and first flown at Hatfield on 26 September 1962 piloted by Group Captain John "Cat's Eyes" Cunningham the company chief test pilot ; the aircraft's performance exceeded expectations, however, it was fitted with the FAW1 shorter outer wing panels, as the new extended wings, had been delayed by strike action at the company.



The prototype  during its first flight, in 1962 without the extended wings


Making its first flight from De Havilland's factory airfield at Christchurch with the new larger wing in June 1963 again by John Cunningham he noted that on approach he found the aircraft unwilling to get through the ground effect until he lost speed by opening the speed breaks to fully open, a trait unwanted in any navel aircraft. this problem was found to be caused by the design of large wing flaps which used so it was changed to a Fowler flap system with spoiler intergraded to give more control at low speed. The second and third aircraft were taken in hand on the assembly line and given the new wings and  the first aircraft was refitted with the FAW1 wing and had a successful carrier as company trails aircraft,  showing the way forward for the upgraded fighter FAW2.



line drawing of the PR1 aircraft



When the second aircraft began flying in aircraft October 1963 the landing problems had been solved and it was found to be actually twenty knots slower in landing configuration than the FAW1 wing equipped prototype one, not a bad thing for a carrier aircraft. During later stages of the flight test program, flutter testing showed that the wings suffered oscillation under certain conditions. This difficulty was partly solved by reducing the stiffness of some wing components. However, a particularly severe high-speed flutter problem was solved only by inserting depleted uranium counterweights as ballast in the extreme outboard wing section
During the high flying trails although a max height of 75,00 feet was achieved a operational ceiling of 70,000  was chosen. To maintain this height the aircraft had to fly very near their never exceed speed (VNE). The margin between that speed and its stall speed at that altitude is only 15 knots  below its maximum speed. This narrow window was referred to by the pilots as the "coffin corner". For 90% of the time on a typical mission the aircraft would be  flying within only five knots above stall, which might cause a sudden  decease in altitude likely to lead to detection, and additionally might overstress the airframe.
In May 1964, the third aircraft and the first with full navel equipment including the powered wing folding system, flown by Captain Eric Melrose "Winkle" Brown, made its first arrested deck landing on the fleet aircraft carrier HMS Ark Royal, and over the following week there were several launchers and landings aboard the ship, with no major problems found, and because the basic airframe was based on the fighter no extra equipment was needed to be onboard the operating ship, so a specialist support flight was not required during a short or emergency deployment.




A order for 12 operational aircraft was placed in September 1964 and 700P Squadron Fleet Air Arm was commissioned on January 5 1966 at RNAS Culdrose, also known as HMS Seahawk, as a operational evaluation unit for the type with the first aircraft being delivered in March of that year.
The trials undertaken by the squadron were designed to test the aircraft in challenging weather conditions, test its onboard systems and define the aircraft operating limits using the painted deck and catapult system at RNAS Culdrose. During the trials 390 deck landings were completed, including 148 night landings, using this facility as well as short deployment onboard the aircraft carriers Ark Royal and Eagle. It was also found during in-flight reflueing trails that the aircraft made a steady tanker aircraft using the standard buddy pod and caring three 200 gallon drop tanks and it was famously photographed with a RAF Valiant tanker plugged in at 30,000ft, This gave the navy the new large capacity aerial tanker they had been looking to acquire for nothing

.

a PR1 refuling a RAF Vallent bomber over the North atlantic 1967

In July 1968 all 12 aircraft were transferred to the operational  750 squadron RNAS and 700 was stood down.
750 squadron was based at HMS Seahawk and provided HMS Ark Royal , and HMS Eagle with aircraft fights as needed for operations but usually 3 aircraft were onboard whenever the ships deployed although extra aircraft could be flown in at any time.

One of the highlights of these deployments was in 1972 when 3 aircraft were onboard HMS Ark Royal when she operated with the US navy sixth fleet in the sea areas around Cyprus and several landing were made onboard the USS Forrestal were the aircraft was closely looked over by the American aircrews, some of who had been onboard the USS America when Lockheed U2 aircraft had been onboard, but lacking folding wings they were found to be unsuitable for extended deployment.
during this time several flights were undertaken over the black sea to photograph the new large hulls being built in Black Sea Shipyard in the Ukraine, which later turned out to be  the first Russian aircraft carriers of the Kiev class.



HMS Ark Royal and USS Forrestal in company


Following a request by the Australians also in 1972 a fight of 4 aircraft were deployed to Australia and the far east officially to operate onboard HMAS Melbourne although they had less than 5 feet of clearance for their starboard wingtip when landing.
One aircraft was lost during this time when during a flight with a two man Australian crew and it had been "zapped" in Australian navy markings, it navigation suit failed and it was unable to recover back to the carrier, but rumours suggest that it shot down by a SA-2 Guideline over north Vietnam.


With the cancelation of the CVA-01 carriers in 1966 and the final decommission of HMS Ark Royal in 1978 the surviving 11 aircraft were in danger of being scraped, and they were offered to the RAF along with the Phantom force, but this was rejected by the RAF, as they had no need for these aircraft, so the aircraft were put up for sale.
The navy also at this time found it had a need to find large cuts in the fixed flying arm of the service, as no large fixed wing aircraft carriers would be available until the harrier equipped through deck cursers came into service, so  The Fleet Requirements and Air Direction Unit (FRADU) was formed at RNAS Yeovilton on 1st December 1972, following the merger of the Fleet Requirements Unit (FRU) which provided target towing and  electronic air warfare targets for the fleet, tasks  Air Direction Training Unit (ADTU) tasked with training Royal Navy personnel in the control of fighter aircraft, and the aircraft used by these units were found to be obsolescent at best, the FRU inventory consisted of de-Havilland Mosquito and Sea Hornets, and the Hawker Sea Fury. the ADUT was little better with  de-Havilland Mosquito T.3s, Supermarine Attacker, Gloster Meteor T.7s.
It was decided to replace the aircraft with a single type and because the sea vixen was in use as both a fighter in the FAW2 model and the recon PR version it was chosen.
On transfer the surviving PR aircraft were taken in hand and several system were updated for its new role and a electronic warfare suit taken from the recently deactivated  Grumman A2F-1H Intruder aircraft from the US Marines, and a new large camera in the rear bay for "mapping work"
Although aircraft were redesignated PR2a aircraft but there now no true standard, as equipment fits and the roles of several aircraft have changed as needed over the years since this refit.
During the Gulf war of 1991 two aircraft fritted with extra electronic warfare equipment were sent to the area but it is not know what role they played in theatre.
There are at this time plans to replace both the FAW2 and  PR2 aircraft with a version of the Dassault Falcon 20 business jets to be flown by civilian contractors, but the fleet air arm historic flight plans to keep at least one of each type flying.

[PR19_Kit]

hehehe, see here :-

http://www.whatifmodelers.com/index.php/topic,30424.0/highlight,sea+vixen.html

[Weaver]

Methinks somebody's wondering what to do with that pair of tiny-scale airliner wings in the spares box.......

[lenny100]

its in build now a cyber-hobby faw.1 and a set of wing from the spare box that are almost the same sweep as the Vixen. I will take photo when i get the charger for the camera (had to get a new one old one died) will make it up in the traditional white and blue/gray of the FAA in the 1970s, as part of the historic flight but still haveing all the later equipment.
never saw that write up by you kit until now but don't mind think alike when you try to place a story behind a build, that started as a discusion at the Perth show?

[JayBee]

He, He, He! 

[PR19_Kit]

That should spring mine into a build state too. They'd make a good pair as mine is based on an FAW2 airframe and is a later mark as it's a PR3.

I'll see if I can find it......

[JayBee]

....but "Lenny" I thought it was meant to be a land based design navalised.
I still think the navalised Me-262 with afterburners in FAA markings would work.



JIm

[lenny100]

....but "Lenny" I thought it was meant to be a land based design navalised.
I still think the navalised Me-262 with afterburners in FAA markings would work.



JIm

i have the other airframe in build also the short nose one doing them inbetween makeing the rigging of the black pearl, also have a ww2 bomber with a larger wing also awating paint..

[Old Wombat]

Lenny?

Are you sure your name's not Kit?



Guy

[tc2324]

Wing span damn it..., we need more wingspan....... 

[PR19_Kit]

Wing span damn it..., we need more wingspan....... 

Exactly! 

[lenny100]

a seventy foot wingspan is as far as a uk carrier based aircraft could go in the 60, and 70s, even then you only have 6 feet clearance on the stb wing tip and you must have a clear rear deck on landing. now if the replacments carriers had come along, such as a upgraded malta class or the cv01 who knows

[Dizzyfugu]

Or a contraprop... or two. 

[JayBee]

You know Lenny, maybe you should come up with 50's/60's Wide Deck carrier design. Possibly a Catamaran or Tri-maran.
Maybe wide enough for normal span ops. with parallel runways. 



Jim

[lenny100]

there is always a uk version of the uss united states



now there is no problem with any wingspan