+++ DISCLAIMER +++
Nothing you see here is real, even though the conversion or the presented background story might be based on historical facts. BEWARE!
Some background:
The Lockheed XFV (sometimes erroneously referred to as the "Salmon", even though this was actually the name of one of its test pilots and not an official designation) was an American experimental tailsitter prototype aircraft built by Lockheed in the early 1950s to demonstrate the operation of a vertical takeoff and landing (VTOL) fighter for protecting convoys.
The Lockheed XFV originated as a result of a proposal issued by the U.S. Navy in 1948 for an aircraft capable of vertical takeoff and landing (VTOL) aboard platforms mounted on the afterdecks of conventional ships. Both Convair and Lockheed competed for the contract, but in 1950 the requirement was revised with a call for a research aircraft capable of eventually evolving into a VTOL ship-based convoy escort fighter. On 19 April 1951, two prototypes were ordered from Lockheed under the designation XFO-1 (company designation was Model 081-40-01). Soon after the contract was awarded, the project designation changed to XFV-1 when the Navy's code for Lockheed was changed from O to V.
The XFV was powered by a 5,332 hp (3,976 kW) Allison YT40-A-6 turboprop engine, composed of two Allison T38 power sections driving three-bladed contra-rotating propellers via a common gearbox. The aircraft had no landing gear, just small castoring wheels at the tips of the tail surfaces which were a reflected cruciform v-tail (forming an x) that extended above and below the fuselage. The wings were diamond-shaped and relatively thin, with straight and sharp leading edges – somewhat foretelling the design of Lockheed’s Mach-2-capable F-104 Starfighter.
To begin flight testing, a temporary non-retractable undercarriage with long braced V-legs was attached to the fuselage, and fixed tail wheels attached to the lower pair of fins. In this form, the aircraft was trucked to Edwards AFB in November 1953 for ground testing and taxiing trials. During one of these tests, at a time when the aft section of the large spinner had not yet been fitted, Lockheed chief test pilot Herman "Fish" Salmon managed to taxi the aircraft past the liftoff speed, and the aircraft made a brief hop on 22 December 1953. The official first flight took place on 16 June 1954.
Full VTOL testing at Edwards AFB was delayed pending the availability of the 7,100 shp Allison T54, which was earmarked to replace the T40 and power eventual serial production aircraft. But the T54 faced severe development delays, esp. its gearbox. Another problem that arose with the new engine was that the propeller blade tips would reach supersonic speed and therefore compressibility problems.
After the brief unintentional hop, the prototype aircraft made a total of 32 flights. The XFV-1 was able to make a few transitions in flight from the conventional to the vertical flight mode and back, and had briefly held in hover at altitude, but the T40 output was simply not enough to ensure proper and secure VTOL operations. Performance remained limited by the confines of the flight test regime. Another issue that arose through the advancements of jet engine designs was the realization that the XFV's top speed would be eclipsed by contemporary fighters. Additionally, the purely manual handling of the aircraft esp. during landing was very demanding - the XFV could only be controlled by highly experienced pilots.
Both Navy and the Marines Corps were still interested in the concept, though, so that, in early 1955, the decision was made to build a limited pre-production series of the aircraft, the FV-2, for operational field tests and evaluation. The FV-2 was the proposed production version (Model 181-43-02), primarily conceived and optimized as a night/all-weather interceptor for point defense, and officially baptized “Solstice”. The FV-2 was powered by the T54-A-16 turboprop, which had eventually overcome its teething troubles and offered a combined power output equivalent of 7,500 shp (5,600 kW) from the propellers and the twin-engines’ residual thrust. Outwardly the different engine was recognizable through two separate circular exhausts which were introduced instead of the XFV’s single shallow ventral opening. The gearbox had been beefed up, too, with additional oil coolers in small ventral fairings behind the contraprops and the propeller blades were aerodynamically improved to better cope with the higher power output and rotation speed. Additionally, an automatic pitch control system was introduced to alleviate the pilot from the delicate control burdens during hover and flight mode transition.
Compared with the XFV, the FV-2 incorporated 150 lb (68 kg) of cockpit armor, along with a 1.5 in (38 mm) bullet-proof windscreen. A Sperry Corporation AN/APS-19 type radar was added in the fixed forward part of the nose spinner under an opaque perspex radome. The AN/APS-19 was primarily a target detection radar with only a limited tracking capability, and it had been introduced with the McDonnell F2H-2N. The radar had a theoretical maximum detection range of 60 km, but in real life air targets could only be detected at much shorter distances. At long ranges the radar was mainly used for navigation and to detect land masses or large ships.
Like the older AN/APS-6, the AN/APS-19 operated in a "Spiral Scan" search pattern. In a spiral scan the radar dish spins rapidly, scanning the area in front of the aircraft following a spiral path. As a result, however targets were not updated on every pass as the radar was pointing at a different angle on each pass. This also made the radar prone to ground clutter effects, which created "pulses" on the radar display. The AN/APS-19 was able to lock onto and track targets within a narrow cone, out to a maximum range of about 1 mile (1.5 km), but to do so the radar had to cease scanning.
The FV-2’s standard armament consisted of four Mk. 11 20 mm cannon fitted in pairs in the two detachable wingtip pods, with 250 rounds each, which fired outside of the wide propeller disc. Alternatively, forty-eight 2¾ in (70 mm) folding-fin rockets could be fitted in similar pods, which could be fired in salvoes against both air and ground targets. Instead of offensive armament, 200 US gal. (165 imp. gal./750 l) auxiliary tanks for ferry flights could be mounted onto the wing tips.
Until June 1956 a total of eleven FV-2s were built and delivered. With US Navy Air Development Squadron 8 (also known as VX-8) at NAS Atlantic City, a dedicated evaluation and maintenance unit for the FV-2 and the operations of VTOL aircraft in general was formed. VX-2 operated closely with its sister unit VX-3 (located at the same base) and operated the FV-2s alongside contemporary types like the Grumman F9F-8 Cougar, which at that time went through carrier-qualification aboard the USS Midway. The Cougars were soon joined by the new, supersonic F-8U-1 Crusaders, which arrived in December 1956. The advent of this supersonic navy jet type rendered the FV-2’s archaic technology and its performance more and more questionable, even though the VTOL concept’s potential and the institutions’ interest in it kept the test unit alive.
The FV-2s were in the following years put through a series of thorough field tests and frequently deployed to land bases all across the USA and abroad. Additionally, operational tests were also conducted on board of various ship types, ranging from carriers with wide flight decks to modified merchant ships with improvised landing platforms. The FV-2s also took part in US Navy and USMC maneuvers, and when not deployed elsewhere the training with new pilots at NAS Atlantic City continued.
During these tests, the demanding handling characteristics of the tailsitter concept in general and the FV-2 in specific were frequently confirmed. Once in flight, however, the FV-2 handled well and was a serious and agile dogfighter – but jet aircraft could easily avoid and outrun it.
Other operational problems soon became apparent, too: while the idea of a VTOL aircraft that was independent from runways or flight bases was highly attractive, the FV-2’s tailsitter concept required a complex and bulky maintenance infrastructure, with many ladders, working platforms and cranes. On the ground, the FV-2 could not move on its own and had to be pushed or towed. However, due to the aircraft’s high center of gravity it had to be handled with great care – two FV-2s were seriously damaged after they toppled over, one at NAS Atlantic City on the ground (it could be repaired and brought back into service), the other aboard a ship at heavy sea, where the aircraft totally got out of control on deck and fell into the sea as a total loss.
To make matters even worse, fundamental operational tasks like refueling, re-arming the aircraft between sorties or even just boarding it were a complicated and slow task, so that the aircraft’s theoretical conceptual benefits were countered by its cumbersome handling.
FV-2 operations furthermore revealed, despite the considerably increased power output of the T54 twin engine that more than compensated for the aircraft’s raised weight, only a marginal improvement of the aircraft’s performance; the FV-2 had simply reached the limits of propeller-driven aircraft. Just the rate of climb was markedly improved, and the extra power made the FV-2’s handling safer than the XFV’s, even though this advancement was only relative because the aircraft’s hazardous handling during transition and landing as well as other conceptual problems prevailed and could not be overcome. The FV-2’s range was also very limited, esp. when it did not carry the fuel tanks on the wing tips, so that the aircraft’s potential service spectrum remained very limited.
Six of the eleven FV-2s that were produced were lost in various accidents within only three years, five pilots were killed. The T54 engine remained unreliable, and the propeller control system which used 25 vacuum tubes was far from reliable, too. Due to the many problems, the FV-2s were grounded in 1959, and when VX-8 was disestablished on 1 March 1960, the whole project was cancelled and all remaining aircraft except for one airframe were scrapped. As of today, Bu.No. 53-3537 resides disassembled in storage at the National Museum of the United States Navy in the former Breech Mechanism Shop of the old Naval Gun Factory on the grounds of the Washington Navy Yard in Washington, D.C., United States, where it waits for restoration and eventual public presentation.
As a historic side note, the FV-2’s detachable wing tip gun pods had a longer and more successful service life: they were the basis for the Mk.4 HIPEG (High Performance External Gun) gun pods. This weapon system’s main purpose became strafing ground targets, and it received a different attachment system for underwing hardpoints and a bigger ammunition supply (750 RPG instead of just 250 on the FV-2). Approximately 1.200 Mk. 4 twin gun pods were manufactured by Hughes Tool Company, later Hughes Helicopter, in Culver City, California. While the system was tested and certified for use on the A-4, the A-6, the A-7, the F-4, and the OV-10, it only saw extended use on the A-4, the F-4, and the OV-10, esp. in Vietnam where the Mk. 4 pod was used extensively for close air support missions.
General characteristics:
Crew: 1
Length/Height: 36 ft 10.25 in (11.23 m)
Wingspan: 30 ft 10.1 in (9.4 m)
Wing area: 246 sq ft (22.85 m²)
Empty weight: 12,388 lb (5,624 kg)
Gross weight: 17,533 lb (7,960 kg)
Max. takeoff weight: 18,159 lb (8,244 kg)
Powerplant:
1× Allison T54-A-16 turboprop with 7,500 shp (5,600 kW) output equivalent,
driving a 6 blade contra-rotating propeller
Performance:
Maximum speed: 585 mph (941 km/h, 509 kn
Cruise speed: 410 mph (660 km/h, 360 kn)
Range: 500 mi (800 km, 430 nmi) with internal fuel
800 mi (1,300 km, 700 nmi) with ferry wing tip tanks
Service ceiling: 46,800 ft (14,300 m)
Rate of climb: 12,750 ft/min (75.0 m/s)
Wing loading: 73.7 lb/sq ft (360 kg/m²)
Armament:
4× 20 mm (.79 in) Mk. 11 machine cannon with a total of 1.000 rounds, or
48× 2.75 in (70 mm) rockets in wingtip pods, or
a pair of 200 US gal. (165 imp. gal./750 l) auxiliary tanks on the wing tips
The kit and its assembly:
Another submission to the “Fifties” group build at whatifmodellers-com, and a really nice what-if aircraft that perfectly fits into the time frame. I had this Pegasus kit in The Stash™ for quite a while and the plan to build an operational USN or USMC aircraft from it in the typical all-dark-blue livery from the early Fifties, and the group build was a good occasion to realize it.
The Pegasus kit was released in 1992, the only other option to build the XFV in 1:72 is a Valom kit which, as a bonus, features the aircraft’s fixed landing gear that was used during flight trials. The Pegasus offering is technically simple and robust, but it is nothing for those who are faint at heart. The warning that the kit requires an experienced builder is not to be underestimated, because the IP kit from the UK comes with white metal parts and no visual instructions, just a verbal description of the building steps. The IP parts (including the canopy, which is one piece, quite thick but also clear) and the decals look good, though.
The IP parts feature flash and uneven seam lines, sprue attachment points are quite thick. The grey IP material had on my specimen different grades of hard-/brittleness, the white metal parts (some of the propeller blades) were bent and had to be re-aligned. No IP parts would fit well (there are no locator pins or other physical aids), the cockpit tub was a mess to assemble and fit into the fuselage. PSR on any seam all around the hull. But even though this sound horrible, the kit goes together relatively easy – thanks to its simplicity.
I made some mods and upgrades, though. One of them was an internal axis construction made from styrene tubes that allow the two propeller discs to move separately (OOB, you just stack and glue the discs onto each other into a rigid nose cone), while the propeller tip with its radome remained fixed – just as in real life. However, due to the parts’ size and resistance against each other, the props could not move as freely as originally intended.
Separate parts for the air intakes as well as the wings and tail surfaces could be mounted with less problems than expected, even though - again – PSR was necessary to hide the seams.
Painting and markings:
As already mentioned, the livery would be rather conservative, because I wanted the aircraft to carry the uniform USN scheme in all-over FS 35042 with white markings, which was dropped in 1955, though. The XFV or a potential serial production derivative would just fit into this time frame, and might have carried the classic all-blue livery for a couple of years more, especially when operated by an evaluation unit. Its unit, VX-8, is totally fictional, though.
The cockpit interior was painted in Humbrol 80 (simulating bright zinc chromate primer), and to have some contrasts I added small red highlights on the fin pod tips and the gun pods' anti-flutter winglets. For some more variety the radome became earth brown with some good weathering, simulating an opaque perspex hood, and I added white (actually a very light gray) checkerboard markings on the "propeller rings", a bit inspired by the spinner markings on German WWII fighters. Subtle, but it looks good and breaks the otherwise very simple livery.
Some post-panel-shading with a lighter blue was done all over the hull, the exhaust area and the gun ports were painted with iron (Revell 91) and treated with graphite for a more metallic shine.
Silver decal stripe material was used to create the CoroGuard leading edges and the fine lines at the flaps on wings and fins - much easier than trying to solve this with paint and brush...
The decals were puzzled together from various dark blue USN aircraft, including a F8F, F9F and F4U sheet. The "XH" code was created with single 1cm hwite letters, the different font is not obvious, thanks to the letter combination.
Finally, the model was sealed with semi-gloss acrylic varnish (still shiny, but not too bright), the radome and the exhaust area were painted with matt varnsh, though.
A cool result, despite the rather dubious kit base. The Pegasus kit is seriously something for experienced builders, but the result looks convincing. The blue USN livery suits the XFV/FV-2 very well, it looks much more elegant than in the original NMF - even though it would, in real life, probably have received the new Gull Gray/White scheme (introduced in late 1955, IIRC, my FV-2 might have been one of the last aircraft to be painted blue). However, the blue scheme IMHO points out the aircraft's highly aerodynamic teardrop shape, esp. the flight pics make the aircraft almost look elegant!
