1:72 Australian Department of Aircraft Production (DAP) "Bunyip" Mk. IIB, aircraft „BF-K/A78-158“ of the Royal Australian Air Force (RAAF) No. 5 Squadron; Piva Airfield/Torokina on Bougainville (New Guinea), November 1944 (Whif/modified Eduard La-7 kit)
+++ DISCLAIMER +++
Nothing you see here is real, even though the conversion or the presented background story might be based on historical facts. BEWARE!
The DAP “Bunyip” fighter was an indigenous development as a successor for the successful CA-12 “Boomerang” fighter, which had been designed in late 1941. The main challenge to this ambition was the fact that fighter aircraft had never been manufactured before in Australia, and that the country’s aircraft industry was relatively young and only had acquired experience through license production.
The CA-12 proved to be successful, even though it had several weak spots. While the CA-12 was lively at low level, its performance fell away rapidly above altitudes of 15,000 ft (4,600 m), and its maximum speed of 265 knots (490 km/h) was not sufficient to make it an effective counter to Japanese fighters like the Zero and the Japanese Army's Nakajima Ki 43 ("Oscar"). Similarly, the best European fighters were reaching almost 350 knots (650 km/h), and even relatively sluggish contemporary fighters – like the Grumman F4F Wildcat and the Curtiss Kittyhawk Mk I – were substantially faster than the Boomerang.
As a consequence, CAC already commenced work upon a new variant which featured performance improvements in terms of speed, climb and ceiling during the CA-12’s flight testing phase. Designated CA-14, this aircraft was designed around an order for 145 U.S.-built, 1,700 hp (1,268 kW) Wright Cyclone R-2600 engines or, alternatively, by the even more powerful 1,850 hp (1,380 kW) Pratt & Whitney R-2800. In parallel, a design team around the Australian Department of Aircraft Production (DAP)’s chief engineer Robert Harford at Melbourne was also ordered to produce an independent, competitive design for a potential CA-12 successor with better overall performance characteristics, but using a different engine.
This was an unusual move, since DAP was an Aircraft Construction Branch of the Department of Supply and Development, an entity that had so far been primarily tasked with the license production of the Bristol Beaufort torpedo bomber, but it was per se not a design or engineering center.
However, the DAP team accepted the challenge and produced the DAP “Bunyip” in record time. This aircraft was a compact single seat fighter aircraft, powered by the British Hercules engine, which was already in RAAF use through the Bristol Beaufighter – a lucky move, since CAC’s proposal for their upgraded CA-12 turned out to be a dud: the intended R-2800 was not available for export from the USA when serial production would have started, since any R-2800 production was allocated to US companies. Even though the Australian government favored CAC’s proposal, the Bunyip was ushered into production after a mere year of development and testing.
The Bunyip was an all-metal construction with a low wing and a fully retractable landing gear. While it roughly shared the CA-12’s outline, it was a completely new construction and aerodynamically much more refined than the Boomerang. The widespread use of light metal alloys instead of wood resulted in a lighter and stiffer structure, and, together with a much higher surface quality and the more powerful engine, many small innovations resulted in a significant improvement in speed and climb. Standard armament consisted of six 0.5” machine guns in the outer wings, firing outside of the propeller arc, and two underwing hardpoints allowed bombs of up to 250 lb (113 kg) caliber to be carried.
The first production variant, the Bunyip Mk. I, was introduced into service in summer 1943. RAAF 79 squadron began combat trials of the new type in late 1943 in support of the unit’s first sweep over Japanese-held territory from Gasmata on New Britain, together with Spitfires and Boomerangs as benchmarks. During this time, the new fighters made 102 individual sorties and claimed 15 aerial victories while losing only four aircraft in combat – a very successful start, even though these initial hot operations revealed several flaws. Another problem was the type’s similarity to the Japanese Nakajima Ki-44 fighter – in order to distinguish the RAAF Bunyips, practically all machines soon received prominent, ID markings in the form of white wing leading edges and tails.
Four Bunyips of this initial batch were lost to non-combat causes, mostly related to engine problems: Initially, the Hercules had the tendency to overheat in the hot and humid climate, this problem was traced back to an undersized oil cooler. The carburetor intakes in the wing roots caused reliability problems, too, due to dust ingestion, and there were problems with the stabilizers that tended to flutter at high speed, too.
After only forty Mk. I aircraft, production quickly changed to the Bunyip Mk. II, which incorporated several detail improvements like an enlarged oil cooler (which had, due to its size, to be re-located under the cockpit), dust filters, a stiffened landing gear and a reinforced tail structure. This variant also introduced an alternative armament of four 20mm Hispano cannon in the outer wings (called Mk. IIB, while the IIA retained the original machine gun armament) as well as the option to carry up to four unguided 60 lb missiles under its wings instead of bombs, what made the Bunyip a formidable ground attack aircraft. This role eventually became the type’s primary role, since, by the time of the Bunyip Mk. II’s introduction, the Spitfire had successfully filled the interceptor role and CAC was on the verge of commencing the manufacture of Mustangs under license to meet the sought bomber escort and air superiority roles. There was also an order for 250 of the new P-51H fighters for the RAAF, which was soon changed into a license production agreement at CAC as the Commonwealth CA-21 Mustang Mk. 24.
The DAP Bunyip’s active career was short and intense, and the aircraft was exclusively operated by the RAAF. In service, the operating units worked closely together with the Royal New Zealand Air Force, undertaking reconnaissance, artillery observation, ground attack, and aerial resupply missions in support of Australian ground troops fighting against the Japanese on Bougainville, New Britain and New Guinea. Until August 1945 a total of 351 Bunyips were produced at DAP’s Melbourne factory. After the end of WWII, the type was quickly phased out, though. Only a handful remained in RAAF service as advanced trainers and as ground instruction airframes until 1949.
Length: 8.6 m (28 ft 3 in)
Wingspan: 9.8 m (32 ft 2 in)
Height: 2.54 m (8 ft 4 in)
Wing area: 17.59 m2 (189.3 sq ft)
Empty weight: 2,638 kg (5,816 lb)
Gross weight: 3,315 kg (7,308 lb)
1× Hercules XVII 14-cylinder, two-row, air-cooled radial, delivering 1,735 hp (1,294 kW),
driving a 3-bladed Hamilton Standard, 11 ft 7 in (3.53 m) diameter constant-speed fully-feathering propeller
Maximum speed: 632 km/h (392 mph)
Cruise speed: 400 km/h (249 mph; 216 kn) at 4,000 m (13,123 ft)
Stall speed: 150 km/h (93 mph; 81 kn)
Range: 765 km (475 miles)
Service ceiling: 11,000 m (36,089 ft)
Rate of climb: 16.7 m/s (3,280 ft/min)
Time to altitude: 5.3 minutes to 5,000 meters (16,404 ft)
4× 20 mm (0.787 in) Hispano or CAC cannons with 200 RPG
Two underwing hardpoints for a total ordnance of 500 lb (227 kg),
or four launch rails for unguided 60 lb missiles
The kit and its assembly:
This is my submission to the 2019 “One Week Group Build” at whatifmodelers.com, and it’s actually a personal interpretation of a fantasy profile drawing created by fellow user PantherG who combined a La-5FN with an all-green RAAF livery. The result looked very convincing, and since the GB was coming up, I decided to turn the drawing into model hardware.
However, my build just stuck loosely to the drawing – the kit basis is an Eduard La-7, and I also wanted to get more away from the aircraft’s Soviet (and very characteristic) origins, primarily through a different, Western engine. A search in the spares box revealed the cowling from a Matchbox Bristol Beaufighter: an appropriate choice, since the engine was actually in RAAF use, and the cowling’s diameter fits well onto the La-7 fuselage. A suitable engine dummy had to be found, too, and I decided to add a spinner-less propeller for an even more different look. The latter was improvised from a B-24 propeller hub (Quickboost) and the La-7’s OOB propeller blades. It was mounted on a metal axis and a styrene tube was added behind the engine block as an adapter.
As a gimmick and a reminder of the CA-12’s characteristic “porcupine” exhaust, I added a similar installation to the engine, even though the flame damper had to be shortened considerably. IIRC, the exhaust stub also comes from a Matchbox Beaufighter.
Other changes concern the armament; all guns were moved into the outer wings, using a set of resin 20mm Hispano cannon (Pavla) for a Hawker Hurricane Mk. IIC. Additionally, I mounted four 60 lb missiles and their respective launch rails under the outer wings – also resin aftermarket parts (Pavla again).
Painting and markings:
PantherG’s original profile drawing showed an all-green La-5FN with Australian markings and characteristic white quick ID markings. Since I already had an RAAF Hurricane in my collection with such a livery, I rather went for a different paint scheme and went for another RAAF “classic”: upper surfaces in foliage green and earth brown, paired with sky blue undersides – plus the white markings.
PantherG was so kind to draw up a matching profile, based on my plans, and I stuck to it as good as possible. The real challenge became the colors, though. RAAF tones, esp. foliage green, are under heavy debate among modelers, and it is hard to find good evidence. Moreover, the RAAF seems to have been very pragmatic when it came to (re-)painting the flying equipment, there must have been a lot of variance and tolerance concerning the paints’ tones.
The most frequent recommendation for foliage green is FS 34092, but while this bluish green tone goes into the right direction, I find it (after having seen trustworthy WWII pictures of RAAF aircraft) to be much too light, lacking chroma. Furthermore, the recommendation of simply using RAF Dark Earth for the RAAF’s Earth Brown appears fishy to me, too. Again, the RAAF tone appears to be much deeper and richer, and less reddish.
As a consequence I decided to mix my own colors and eventually settled on a 3:1 mix of IJN Green (Modelmaster 2116) plus Humbrol 30 (Dark Green) and a 3:1 mix of Humbrol 10 (Brown) with Modelmaster 2108 (French Earth Brown) – both became relatively dark tones, but this would only make the white ID markings and the grey tactical codes better stand out. The Sky Blue underneath was also a light but rich tone and I found in Modelmaster 2131 (Medium Su-27 Blue) a suitable approximation.
The white tail was painted with a mix of Humbrol 34 and some 147 (White and Light Grey FS 36495), while the wings’ white leading edges were created with white water slide decal sheet material (TL Modellbau) and some touch-ups with white enamel paint. A convenient but somewhat tricky solution that saved time and masking hazards – I guess that painting would have been the more hazardous alternative.
The kit received a standard black ink wash and panels were post-shaded with lightened basic tones, visually adding surface structures that are actually not there.
The interior of cockpit and landing gear were painted with RAF Interior Green (Humbrol 78) – I checked several sources and pictures of museum pics, and this seems to have been the typical tone for RAAF aircraft (or at least those that had been built in Australia).
The decals were puzzled together from various sources. The roundels belong to an RAAF Spitfire (from a Carpena sheet), and this aircraft’s serial number was cut into pieces and re-arranged for the Bunyip. The tactical codes were created with single RAF font letters in medium sea grey from Xtradecal.
Some soot stains around the exhaust and the cannon nozzles was added with grinded graphite, and some signs of wear added on the leading edges and around the cockpit as well as the engine with dry-brushed light grey and silver. Finally, the kit was sealed with matt acrylic varnish (Italeri), and some oils stains (Tamiya Smoke) as well as small details (wire antenna, position lights) were added. Voilà.
Not a complex build, but the time frame of just nine days made this one, also due to the engine surgery, a tough build. Nevertheless, I am quite happy with the result – the La-7/RAAF combo just looks right, like a natural successor to the stubby CAC Boomerang.