Magna Models 1/72 Martin-Baker MB.3

Designed by Sir James Martin, the third aircraft built by the Martin-Baker Aircraft Company, the M.B.3, was a prototype fighter. First flown on August 31, 1942. It was fast at 415 mph, and one of the heaviest armed single engined aircraft at the time, with six 20 mm cannon with 200 rounds per gun. It was powered by a 2000hp Napier Sabre II, 24 cylinder sleeve valve engine. On September 12, 1942, the aircraft crashed after engine failure, (a sleeve drive crank broke), killing the pilot, company partner Captain Valentine Baker.

 This crash spurred Sir James Martin's interest in aircrew safety, with the first Martin-Baker ejection seat test on the 24^th of January 1945. The incomplete second prototype was extensively modified and fitted with a Griffon engine to become the M.B.5.  

Coming in a small top opening box, there are 13 cream coloured resin parts and 18 white metal parts supplied. There are four vac-formed canopies, two each of the razorback and bubble versions. The decal sheet had just two yellow 'P' in a circle, prototype markings, nothing else.

 All the resin parts had a thick greasy layer of mould release wax. Here is a more complete preview.

The first step was cleaning up the resin parts. The pouring lugs and flash was removed with a combination of sawing, filing, sanding, hacking, grinding and carving. It was a big job and took the best part of an evening.  The parts were then all washed in a mix of hot soapy water and rubbing alcohol, given a good scrub and left to soak overnight in the brew. Next morning another scrub then left to dry.

 Dry fitting revealed that the cockpit floor part was too large for the fuselage, so the floor and sides were carved down to fit. I separated one of the vac-formed bubble canopies from the card and used it to check clearance to the large headrest. Next step was to get the white metal instrument panel to fit. There is a slot formed in the right fuselage half for it, but was too forward and low, blocking access to the rudder pedals. The panel was too wide to fit just below the coaming, where I expected it to go. I got out the motor tool and gouged out a channel for the panel and eventually made it fit.

 I then started detail painting the cockpit. The instructions suggested interior green which seemed reasonable. I picked out the moulded seatbelts in blue, and other details in black and silver. I then added the pre-painted white metal control column and closed up the fuselage. I managed to line it up ok along the top deck, but ended up with a step at the rear lower joint and tail. Not too bad, filled the whole joint with superglue, and cleaned it up.

The wings didn't fit, they are much thinner and shorter than the roots, and if joined as moulded will dangle down at about 10 degrees anhedral. Just to add to the fun, there was a huge bubble at the leading edge of the port root. I matched them up to the roots at the top surface at the front and as best as I could along the rest of the top surface, the curvature of the roots does not match the aerofoil of the wings very well. I ran a bead of superglue to tidy up the top surface, then filled the huge gap along the bottom surface with several layers of thick superglue. There was a step between the wing and the root of about 2mm at the thickest, about mid cord.

 When it was all dry and hard, (not too long as I'd used accelerator), I ground down the wing roots with the machine. Second time to use the Dremel on this kit, resin dust everywhere. I was reasonably careful, wearing a dust mask and safety glasses. Tidied up the wing root with various half round files. Took the opportunity to grind out the resin blobs in the undercarriage wells. Gave it all a wet sand and a good wash.

 I then added the remaining resin bits, spinner, tailplane, intake, and the two underwing radiators. Nothing fitted well, needing plenty of filling and sanding, but no more grinding. Fixed a few more bubbles, and found a couple more blobs of resin and moulding silicon in the wheel wells.

I decided to do a desert air force scheme for No 451 Squadron RAAF. They operated Hurricanes, Spitfires, Lysanders and briefly Typhoons. I like the desert scheme of earth, stone and light blue, and could gather the roundels from the decal stash. I have a few sets of letters in various colours and styles so could get the squadron code 'BQ' and an individual aircraft letter.

 I painted the underside Tamiya light blue, and did the topside overall light earth. The good news was the paint adhered well to the resin, all that sanding and washing helped that. I then freehand painted an approximation of the typical camouflage pattern in a darker brown.

While the various layers of paint were drying, I started the clean up of the white metal parts. All had flash and moulding seams to be removed, and in some cases pouring lugs. Most of the clean up was done by cutting with side cutters and scraping with a scalpel blade, which just about destroyed the blade. Finished off with needle files and sanded where I could. I attached the white metal wheel legs and doors, tailwheel, pitot, radio mast and propeller blades, most of which fitted into small holes I drilled into the model for strength. I don't trust butt joints on those tiny parts.

 The cannon fairings had a bad case of mould misalignment, and needed a lot of work. They looked like baseball bats. I chucked them in the Dremel, filing and sanding them at low speed. They are still the wrong shape. I hope it really was white metal and not lead as there was dust everywhere again. The moulding of the metal parts was a lot crisper than the resin.

 After all the work on the cannon barrels, they still didn't look good, and were really far to fat. I made replacement barrels from 0.5mm brass tube, with 0.3mm inside diameter. A quick calculation reveals that works out to 21.6mm calibre which is close enough for government work. My M.B.3 now has unfaired cannons. I attached the vac-formed bubble canopy with Krystal Klear. It needed a little trimming but fitted fine.

I had to touch up a few spots around the white metal parts and the canopy, then I then gave it a coat of floor polish to help the decals.

 The roundels and fin flash decals were taken from an old Matchbox Mosquito sheet, worked fine but thick and glossy, needed a couple of doses of Mr Softer. The squadron codes came from Altmark decal set A18, 24” sky letters, very thin with continuous carrier, I had a bit of trouble with them folding, conformed well with Mr Setter. I didn't bother with a serial.

 Another small touch up paint here and there, then a coat of floor polish to seal everything. A final spray of dull coat, this time remembering to mask the canopy!

 A rather difficult build of a one-off prototype fighter. The finished result looks the part, but it was a lot of work. I used the Dremel more on this build than I have on any other kit. The cannon supplied were useless and the only bits that needed replacement. I had to supply my own decals.

 Recommended for experienced modellers.

 William Green, Fighters Volume 2, Macdonald, London 1961

 http://www.awm.gov.au/units/unit_11145.asp

 http://www.martin-baker.com

Peter Burstow

May 2013

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