Unicraft 1/72 Martin-Baker Tankbuster

KIT #:  
PRICE: $27.00
DECALS: One option
REVIEWER: Peter Burstow
NOTES: Short run resin kit

HISTORY

Conceived by Sir James Martin, the Tankbuster was a paper design. Powered by a Rolls-Royce Griffon and armed with an anti-tank gun, it would have been a formidable ground attack aircraft. The gun proposed was the Ordnance QF-6 6 pound anti-tank gun, 57mm bore, also produced in the U.S. as the M1. A later modification of the GF-6 was the Mollins gun as used in the Tse-Tse Mosquito.

It was intended to include 4900 lbs of ½ inch armour plate. The aircraft was a conceptual forerunner of the A-10.  

THE KIT

Coming in a very small top opening box, there are 23 cream coloured resin parts and a single vac-formed canopy. The decal sheet had markings for one RAF aircraft. An interesting additional part is a resin mould of the canopy, so another could be smash or vacuum moulded. 

The parts are full of bubbles, there are plenty that will need attention. I counted 41 in an 8mm diameter circle on the fuselage. There is a warning about brittle resin and they are not kidding.

CONSTRUCTION

 The first step was cleaning up the resin parts. The pouring lugs and flash was removed by sawing and sanding. All done wet to minimise dust. The instructions recommend using a hot knife, but I believe the fumes are likely to be even more toxic than resin dust.

 There were a lot of lumps and bumps and other moulding glitches that needed cleaning up, that exposed more bubbles to be repaired. The parts were then all washed in hot soapy water, given a good scrub and left to dry.

 I started by assembling the fuselage, the port half is moulded in two pieces, the starboard side is one piece. The cockpit is furnished with a two part seat and an instrument panel. There is a second instrument panel supplied, must be for a different kit as it is far too wide to fit. I attached these parts to the starboard fuselage third. Almost nothing of the cockpit is visible when assembled, so I painted the panel black, and everything else dark green.

I then added the port front fuselage half, fit was not to bad, but it will need quite a bit of filling. I found a review on another site which confirmed my thought that this would be a tail-sitter, so I filled the forward fuselage with lead shot (No.8 Winchester) and superglue. The rear port fuselage piece was about 1mm too narrow at the front, so I matched it along the side of the fuselage, leaving a long wedge shaped gap along the top surface. 

I then added the one piece wing, a lot of preparation needed, as it had a pouring lug down most of the leading edge, As I removed this more and more bubbles appeared. It was also covered in little resin lumps, especially in the panel lines and the aileron hinge lines, most of these revealed another bubble as I cut them off. The wing fitted, sort off. Good fit at the trailing edge, about 2mm gaps at the roots, and a canyon at the leading edge.

 I mixed up some 2 part automotive body filler and used that for the fuselage, wing gaps and some of the larger bubbles. A good wet sand then I went over all the joints, lots of bubbles, and most of the nose with Mr Surfacer 1000. Another sanding session and more bubbles appeared, so more filling and sanding. Gave it a coat of primer before proceeding, and found a few more things to fix.

 The smaller bits all suffered from a mould misalignment, with a 1mm or so step. Had to thin the tail booms a lot to get rid of the step. The radiator intake and exit scoops were not too bad, and I recovered the u/c legs with a lot of carving and sanding. I had to thin the edges of the scoops to make them more like sheet metal, rather than armour plate.

 Added the two scoops, got a good fit (for this kit anyway), along the top edge, the bottom edges had a big gap, just about impossible to get at just above the wing. I faired the scoops in with superglue, and then used some Mr Surfacer to tidy up.

Added the tail booms and the tailplane, always a tricky operation on twin boom aircraft. The booms were a good deal smaller than the stubs mounted on the wing as a result of the step removal, I lined them up with the upper surface and left a step underneath. It ended up a little out of square, but so was everything else on this model! From most angles it looks OK.

 There was a location marked for the main undercarriage legs, but if there was one for the nose leg I probably sanded it off, so I used the 3 view in the instructions to position it. It's a firm tail sitter, despite the nose forward of the cockpit being filled with lead, I filled the cockpit with more lead, but still not enough. I detached the main undercarriage legs and moved them 2mm towards the tail, that was just enough for it to become balanced. See what happens when I add the prop.

I decided to go with the box art desert air force scheme. First another coat of all-surfaces automotive primer, whoops, more bubbles and other glitches to fix. I painted the underside light blue, and did the topside light and dark brown.

FINAL CONSTRUCTION

 The resin gun part was horrible so I cast around for a replacement. Had a look at the Airfix “Bren Gun Carrier and 6 pdr anti-tank gun” as a possible donor, it's the right gun, but far too small. A little research and I discovered that when first released in 1964 the kit was OO scale (1/76.2), and has since magically been resized to 1/72. It looks much smaller than that. I then tried a Paragon Mosquito conversion, gun is the right bore, but too short. I settled eventually on a 6 barrel mini-gun from a scrapped 1/32 helicopter kit, hey! this is a Mark 2 Tank-Buster.

Like the gun, the supplied resin blades were not too good. The spinner was OK, so I used a cuffed Hamilton Standard propeller, left over from a recent Mustang build. These blades where much nicer looking and close to the right diameter. I joined the spinner to the prop, and added a disc of plasticard to the front, then filled the void around the hub.

A Hobbyboss Tempest kit donated 8 rockets and rails, which I installed under the wings.

I had to touch up a few spots, then I then gave it a coat of floor polish to help the decals. I used the supplied kit decals which were ALPS style with a continuous carrier film. The colours were a little bright and shiny, and registration was not the best, with a white line along the edges of the roundels and fin flashes. They worked OK with a little Mr Mark Setter.

Another small touch up paint here and there, including going over the edges of the roundels and flashes to hide the white line and shiny carrier. Then a I gave it a coat of floor polish with some added Tamiya buff to seal and dull the decals. A final spray of dull coat and call it done.

CONCLUSIONS

A rather difficult build of a concept ground attack aircraft. Only a few parts, but fit issues and those bubbles meant a lot of work and not much fun. I had a real struggle to remain motivated enough to finish it, but resisted temptation to abandon it.  It looks much better finished than I expected.

 Recommended for practice in bubble filling and mould step repair.

REFERENCE

 http://forum.worldofwarplanes.eu/index.php?/topic/8912-martin-baker-prototype-concept-aircraft-photo-archive/

Peter Burstow

November 2013

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