+++ DISCLAIMER +++
Nothing you see here is real, even though the model, the conversion or the presented background story might be based on historical facts. BEWARE!
Some background:
The EKW (Eidgenoessische Konstruktionswerkstaette) D-44 was a Swiss, single-seat low-wing monoplane fighter and attack aircraft. It used a twin boom fuselage with a pusher engine, giving the aircraft an unusual, almost jet-like appearance. Its design started in 1943 when the former Federal Constructions Works became a separate unit of the Swiss Armed Forces at Emmen, after the Swiss government’s decision to embark on a major expansion program in preparation for the possibility of being drawn into the Second World War. The project was designated D-44 and was constructed around a single German Daimler-Benz DB 605B engine that was positioned to the rear of the fuselage nacelle, directly behind the pilot, and drove a pusher propeller. This arrangement allowed guns to be carried in the aircraft's nose while providing the pilot with good visibility, and it concentrated the aircraft’s major masses into the airframe’s center of gravity, so that the aircraft would be more agile than a conventional design. To enable the pilot to bail out without hitting the propeller behind him, the design also adopted an ejection seat, operated with pressurized air.
The Swiss Air Force ordered two prototype D-44 fighters on 31 May 1944, and if the prototypes were successful, it planned to order five pre-production models and sixty-five production aircraft. The aircraft was intended to be fitted with four 20-millimeter (0.8 in) MG 151 autocannon in the nose and in the twin-booms and was supposed to be able to carry 1,000 kilograms (2,200 lb) of ordnance under the wings. The fuel was stowed between the cockpit and the engine, together with a pair of self-sealing tanks inside of the inner wings, and a radiator for the inline engine was placed in a shallow trough under the rear fuselage. The tricycle landing gear – another novel design feature – was fully retractable and was stowed in the forward fuselage as well as in the sleek twin booms under the slightly swept wings.
However, soon major design changes had to be made. Due to the worsening situation for Germany, the favored DB 605B engine was not available for export or license production, just as the guns and other aircraft components. F+W’s designers wanted to use a British Rolls-Royce Griffon engine instead, but it proved to be too difficult to obtain, either. As an alternative, a Hispano-Suiza 12Z was temporarily envisioned, which was built by EKW at that time, leading to the project designation D-4401. But this engine was still too immature to be used, and there were doubts about the D-44’s performance with a powerplant that would have an output of around 1.500 hp when the D-44 required an engine with 1.800 hp and more to be competitive. These fundamental procurement problems could not be overcome until the end of hostilities in Continental Europe in mid-1945.
Eventually, EKW’s engineers were able to acquire a batch of British Napier Sabre II H-24 piston engines which had powered the Hawker Typhoon and were overstock material now, after production had ended and the RAF had retired the type by October 1945. The Sabre II promised high reliability and an output of 2,200 hp and more, resulting in an estimated top speed of 750 km/h (470 mph, 400 kn) at 8,700 m (28,500 ft). Since the Sabre’s cylinders were opposed, the motion in one was balanced by the motion on the opposing side, eliminating both first order and second order vibration. EKW hoped to use air cooling on the Sabre (as Napier originally had planned), but in service, the rear cylinders proved to be impossible to cool properly, which made the engines unreliable, and so the D-44 adopted water cooling.
To accommodate the bigger and heavier engine, the D-44’s fuselage had to be modified with different and stronger engine bearings. The radiator had to be enlarged, too, and its deeper fairing was also used to replace a prominent scoop on the left side of the fuselage that originally provided the engine with air, so that the overall frontal area did not increase much. A six-bladed contraprop was fitted, together with the respective reduction gearbox, to effectively exploit the Sabre’s high output and to accommodate enough propeller disc area in the confined space between the tail booms. As a side benefit, the contraprop countered the engine’s massive torque that would have affected handling with a simple propeller, esp. at slow speed. In this new guise the aircraft was re-designated D-4402 and cleared for production.
Only the first D-4402 prototype was intended to be fitted with guns, so the second prototype was completed first, beginning taxiing tests in December 1946. Test pilot Guillaume Fournier attempted to make the first flight on 13 January 1946. Further high-speed taxiing trials were made in February with promising results, but the elevator had to be enlarged from an area of 1.75 to 2.6 m² (18.8 to 28.0 sq ft) before the D-4402 could make its maiden flight on 1 April. After some more modifications, including a modified main armament which consisted now of four indigenous Oerlikon 20 mm cannon, all mounted in the lower nose, modified fins (extended downwards and outfitted with small, fixed wheels to protect the tail booms), elevators and landing gear doors, D-4402 #02 made its next flight on 21 April. Its configuration set the standard for the following serial production aircraft.
Flight tests lasted for more than a year, and during this period the initial ejection seat, which had been powered by compressed air, was changed to a simpler and lighter model that used a gunpowder charge inside a telescoping tube attached to the seat. A total of five prototypes were built as planned – including a static airframe and two pre-production aircraft that already incorporated some modifications that had been tested on the prototypes #1 and #2.
The first example from the first serial production batch of thirty aircraft was delivered to the Swiss Air Force on 1 December 1947. Construction was at EKW’s main plant in Emmen, and deliveries of this model ran until 5 December 1948, when deliveries of a second batch totaled thirty more D-4402s. A potential third order was cancelled, prior to the production line ending in 1950.
The D-4402 showed good performance and turned out to be a very stable weapon platform, even though its performance fell a little short the projected estimates. Despite the original intention for the type to be principally used in air defense roles, in service, the D-4402 was utilized mainly in the light bomber and attack role. Its active career did not last long, though: within less than four years some squadrons were already being re-equipped with a new generation of jet fighters capable of far greater speed, such as the de Havilland Vampire. The D-4402 was used only by the Swiss Air Force and due to the quick advances of jet propulsion the D-4402’s frontline career already ended in 1958. The type was completely retired by 1965, after being used as advanced trainers and as instructional airframes.
General characteristics:
Crew: 1
Length: 11.88 m (38 ft 11 in)
Wingspan: 11.14 m (36 ft 6 in)
Height:
Wing area: 23.1 m2 (221 sq ft)
Empty weight: 3,645 kg (8,036 lb)
Gross weight: 4,928 kg (10,864 lb)
Gross weight: 7,261 kg (16,008 lb)
Fuel capacity: 1,413-litre (311 imp gal; 373 US gal) internally
Powerplant:
1× Napier Sabre II water-cooled H-24 piston engine, 1,680 kW (2,250 hp),
driving a 6-bladed contra-rotating propeller with 2.7 m (8 ft 10 in) diameter
Performance:
Maximum speed: 730 km/h (450 mph, 390 kn) at 8,500 m (27,900 ft)
Cruise speed: 422 km/h (262 mph, 228 kn) at 4,000 m (13,000 ft)
Range: 852 km (529 mi, 460 nmi) with internal fuel
Service ceiling: 12,000 m (39,000 ft)
Time to altitude: 8,000 m (26,000 ft) in 10 minutes 40 seconds
Wing loading: 240.4 kg/m2 (49.2 lb/sq ft)
Power/mass: 3.1 kg/kW (5.1 lb/hp)
Armament:
4× 20 mm (0.8 in) Oerlikon autocannon with 200 RPG in the lower nose
Underwing hardpoints for bombs, unguided missiles or drop tanks for a
total external ordnance of 1.000 kg (2,200 lb)
The kit and its assembly:
This major kitbashing project was spawned from the idea: “What if the Kyushu J7W Shinden had had a more conventional layout, as a twin boom pusher?”. The overall proportions of a Hasegawa kit in The Stash™ looked promising, and I also had a Heller J21 kit that appeared appropriate to donate its tail booms and maybe other stuff, too.
On this vague basis I started to let the saw sing. Work started with the tail, because the J21’s elevator span would define the distance between the booms and their location on the J7W’s wings. Since the J21’s fins appeared a bit small and to change the overall look I replaced them with the swept fins from the J7W, what required some serious PSR and a new location for the elevator.
In parallel I started with the fuselage, which would be heavily modified. Before hardware work even started, I decided that the J7W’s radial engine would be replaced by a liquid-cooled in-line alternative, and I found the nose section of a Matchbox Hawker Tempest in the donor bank that had very good dimensions to make it fit in/onto the J7W’s rear fuselage. However, the exhaust stubs were missing, as well as the prop (which would have been much too big for the small space between the booms and for the ground clearance, anyway) – these were replaced with donors from a Special Hobby kit for late, Griffon-powered Spitfires. The respective contraprop was built with reversed blades, mounted on a metal axis (together with a matching adapter inside the Tempest’s Sabre engine), and received a tapered “plug” to bridge the different diameters between the engine and the smaller spinner. However, the contraprop was just small enough to fit between the booms, so that it was a very plausible solution.
Since the Sabre was a liquid-cooled engine a radiator had to be mounted, and the J7W’s original colling air intakes became superfluous. In a major stunt I decided to get completely rid of them and cut the respective fuselage walls behind the cockpit out and re-arranged and PSRed them into a slimmer shape that would blend directly into the Sabre section. Lots of work, but IMHO it paid out. The Tempest’s massive chin radiator turned out to be unusable for the build, so I replaced it with a shallower alternative, mounted under the fuselage between the tail booms, partially covering the J7W’s original landing gear well, which were filled because the landing gear would now retract into the tail booms, using the J21 parts.
Another major change was the nose section, which could only be tackled after the wings and the tail booms had been combined with the hull – the nose had to be shortened dramatically, but without knowing the proportions of the “new aircraft” any earlier attempt would have been very risky.
I eventually found a surprisingly good match (diameter and shape were almost perfect!) in a leftover nose section from an Airfix F-80 Shooting Star. However, one major problem persisted: the front landing gear and its respective well. Through the shorter nose it had to retract backwards, and the front leg’s considerable length would make the well reach deep under the cockpit floor (taken over OOB from the J7W kit, just with a new seat, and the canopy was used, too, even though cut into three sections to present the model with an open cockpit). I was eventually able to implant the J7W’s well, together with as much steel beads as possible, into the nose, so that there was actually a front landing gear well with full interior. Once the main landing gear struts had been mounted I decided to use the J7W’s stalky front wheel strut.
Painting and markings:
This was quite a challenge, because I initially was not certain who the manufacturer and operator of this fictional aircraft should be? Japan and Sweden were initial choices, but since there had been some indigenous and quite exotic designs after WWII I eventually settled for Switzerland. Another reason for this choice was the fact that I had wanted to apply the rather unique “layered” camouflage on a model, and this was great opportunity.
I have no information about the colors/tones that had been used, e. g. on some Doflug D-3801/03 fighters or one or two EFW P.16 prototypes. But apparently some darker shades, including dark green and earth brown (and probably more!) were applied with broad brushes or even a mop over a grey uniform basis, probably the same light tone that was used for the undersides. From the poor b/w pics I’d say that every aircraft received an individual pattern, and I used a color picture of a P.16 (which offered a good view on the upper surfaces, even though in a very weathered state) as benchmark and tried to replicate the look.
Things started with an overall coat with Humbrol 165 (RAF Medium Sea Grey). Then I used thinned acrylic paint to layer wavy lines with Revell 45 (Farngrau, close to RLM02) and 82 (Earth), both tones offered only little contrast to the underlying grey. Then came more wiggles with 42 (Gelboliv, RAL 6014) and finally with 84 (Lederbraun, RAL 8027) – resulting in a very disruptive pattern that really breaks up the airframe’s outlines and hides almost all surface details. Disturbingly effective!
The cockpit was painted in a very dark grey (Revell 06, Anthracite) and the landing gear as well as the respective wells in a mix of Humbrol 11 and 165, for a dull metallic grey.
After that the model received an overall black ink washing as well as some post-shading on the lower surfaces – a futile task on the upper camouflage, because of its cluttered character!
Markings became minimal, just with Swiss roundels procured from an F-5E sheet for the fins and from a generic markings sheet from TL Modellbau for the bigger wing markings. The tactical code was adapted from a Swiss BAe Hawk trainer (U-1257, the U was turned into a J with a cutter knife…). To add some color I painted the spinner red and added fictional unit markings to the nose, as well as some red warning markings, stencils and fake louvres around the engine.
