Background

The US Army Air Corps [USAAC] Circular proposal X-609 for a fighter capable of intercepting high altitude hostile aircraft led Bell’s chief engineer set about designing the aircraft what would be a unique looking fighter. The airframe was designed around the 37mm Oldsmobile T9 [later M4] canon. As the calibre of the canon was much greater than the standard 20mm canon, it was impossible to accommodate the engine in the forward fuselage. As a result, the engine was placed in the centre of the fuselage behind the pilot with the turbo charger placed in the belly. The air intake for the super charger was placed on the side of the fuselage similar to the intakes on the tail boom of the P-38. A ten-foot-long prop shaft connected the Allison V-1710 liquid-cooled V-12 engine to the propeller. The resultant XP-39 was submitted to the National Advisory Committee for Aeronautics [NACA] for tests. Unfortunately, it was found that there was high amount of drag resulting from the engine installation, oil cooler and intercooler scoops as well as the turbocharger. Changes were made from the recommendations of NACA including the deleting of the turbocharger. Its removal had a noticeable negative effect regarding high altitude performance. The glycol-cooled radiator was fitted in the wing centre section, immediately beneath the engine; it was flanked by the drum-shaped oil coolers. Air for the radiator and oil coolers was drawn in through intakes in wing leading edges and was directed via four ducts to the radiator faces. The air was then exhausted through three controllable hinged flaps in the fuselage centre section. Air for the carburettor was drawn in through a raised oval intake immediately aft of the rear canopy. Despite the change in aerodynamics the P-39 never attended speeds beyond 400mph. The lack of free space in the fuselage meant internal fuel storage was limited to the wing. As a result, range was disappointing and the P-39 generally flew on missions with external fuel tanks. Despite its limitations the P-39 saw service throughout WWII with the USAAF, Soviet AF, Free French, the RAF, and the Italian Co-Belligerent AF.

The P-39N the subject of this edition, is the final production version of the Airacobra. Production ceased in August 1944. There were quite a few sub variants of the P-39N during the production run including photo reconnaissance aircraft. The Soviet Air Force used the P-39N to great effect and became the largest user of the type outside the US. Most of the aerial combat on the Eastern Front took place at low and medium altitudes. The Soviets developed effective aerial combat tactics suiting the strengths of the P-39. Five of the ten highest scoring Soviet aces logged the majority of their kills in P-39s.

The Kit

Arma Hobby’s 1:72 scale P-39N comes in a side opening box and contains:

• 2 x grey plastic sprues
• 1 x clear plastic sprue
• 3 x steel ball bearings [nose weight]
• 1 x sheet of decals
• 1 x sheets of kabuki paint masks
• Instruction manual

The kits contents are packed into a single bag for security with the clear plastic sprue and ball bearings bagged individually. The decals and masks are placed inside the instructions. The surface of the grey plastic parts is matt in nature. The recessed detail is superbly executed and will take a wash if you want to bring out the panel lines and fasteners. There are locating pins and holes to help with alignment of the main parts. Parts are beautifully moulded and in scale, though some of the parts look very delicate. So, some care will be need removing them from the sprues.

Thirteen plastic parts making up a very detailed office. The inside surfaces of the fuselage have fine raised detail in the cockpit area. The instrument panel [IP] and central console has sharp detail and the instrument faces can be found on the decal sheet. The prop shaft is incorporated with the cockpit floor. Part of the cockpit floor forms a section of the roof of the forward undercarriage bay. The seat is attached to a nicely detailed frame. The seat harnesses are to be found on the decal sheet. The decking to the rear of the pilot and covering the engine is nicely detailed. Arma Hobby advise drilling a couple of holes into the deck to fit the radio.

The canopy and windscreen are one piece with separate car style doors. The doors can be displayed open. Plastic is nice and clear and Kabuki paint masks are provided. There are around nine decals to attach to both doors.

The fuselage is split vertically with separate vertical fin and separate rudder as well as alternate pieces for the nose armament. Some of the panel lines around the nose need to be filled for accuracy.  A thoughtful inclusion is the three-ball bearing [BB] to counter balance the weight of the tail as the Airacobra had a tricycle undercarriage. There is a plastic part created specifically for the BB to fit into. To fit this part the raised ejector pins need to be removed from inside the nose section. There are two different styles of exhaust Included though one is only used. The one-piece prop has a separate spinner and into the spinner goes a separate canon barrel. 

The main wings are made up from three pieces, with the lower wing being one-piece. The control surfaces and flaps are moulded in the neutral position. The gap between aileron and wing is correctly wider and deeper than the panel lines. The three vent flaps under the belly for the coolant and oil radiators are separate and presumably can be displayed open or closed. The detail moulded into the roof of the undercarriage bay is well done. There is no sign of shrinkage visible on the upper half of the wing caused by the detail. The lower wing needs holes drilling to fit the belly tank/bomb. 0.50 calibre guns are separate and fit into recesses on the leading edge. Some of the detail on the wing does need changing, the ID lights under the wing tips to be filled. 

The detail on the parts making up the undercarriage is superb. Particularly noteworthy is the detail in the wing, on the inside of the undercarriage doors and the separate walls of the forward undercarriage bay. The latter are attached to the cockpit floor. The oleos of the main undercarriage display enough compression so that the sit of the model along with the weighted one-piece wheels should look good. The tyre manufacturer Firestone features on the sidewall in low relief. Both forward and main undercarriage units can be left off until painting is completed. The instructions for the construction of the front undercarriage is explicit, with numerous line drawing showing its build and fitting.

Included are a 250lb and 500lb bombs as well as the almost permanently fitted fuel tank. These are fitted in the belly position.

The kabuki paint masks are for the windscreen, canopy, both sides of the doors, wheels and I think the landing light. Arma Hobby do not provide any guidance for positioning the masks, though it doesn’t take too many brain cells to work out where they go.

The decals are produced by Techmod and includes the various insignia and markings, seat harness, cockpit instruments, placards, art work and wing walkways. There are quite a few stencils to add particularly on the wings. There is a section in the instructions illustrating the location of each stencil. The definition, registration and colour density of the decals is top class. The glossy carrier film is kept to a minimum.

The twelve-page A5 format instructions seem clear. Construction instructions are colour coded and a useful aid in construction are the multiple view diagrams. The painting guide is in colour with four profile views of each subject. The stencil guide also has four profile view of the airframe too. There are several paint manufactures referenced in the instructions including: Hataka, AK RC, Lifecolor, Ammo, Humbrol, Vallejo and Tamiya.

Markings Options:

There are four marking options, option 4 is a bonus. Camouflage is predominantly olive drab upper surface and light grey under surface though Arma Hobby’s selection of marking options is far from boring. Markings include:

• P-39N Airacobra 42-9033 „White 01”. 100th Guards Fighter Regiment, pilot: Grigoriy Dol’nikov, 1943-1945
• P-39N Airacobra 42-18354. 345th Fighter Squadron, Sardinia-Corsica, spring 1944.
• P-39N Airacobra 42-18736. Cdt. Jean Machet de la Martinière, GC 1/4 Navarre commander. Reghaia airbase, Algeria, March 1944.
• P-39N Airacobra 42-9033 „White 01”. 100th Guards Fighter Regiment, pilot: Iwan Babak, 1943-1945

Conclusions

This is another superb release from Arma Hobby. This edition certainly lives up to the high standards that Arma Hobby are setting themselves with the quality of detail. There are many examples of built models on the internet, with positive feedback with the build quality. Highly recommended.

Price: €26.50

Available from Arma Hobby

Many thanks to Arma Hobby for supplying this kit for review.

70056 – Bell P-39N Airacobra – 1:72

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