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| First adopted by the Royal Navy, the long barrelled 50-caliber Molins gun was added to the Mosquito airframe as an anti-tank gun but Costal Command used the Tsetse in the role of sub-busting. |
The story of the deHavilland Mosquito is well-known, but the story of the weapon that led to the Mosquito FB. Mk. XVIII is not so familiar. In 1941, in order to meet a perceived need for a rapid-reaction vehicle-mounted anti-tank gun, British armaments engineers stumbled across the idea of fitting the 6-pounder 7cwt anti-tank weapon with an autoloading mechanism. This would be mounted in a fast, armored tank destroyer. The Molins Machinery Company (previously mainly noted for making cigarette manufacturing machinery) designed and produced an autoloading mechanism; but by the time it was ready for testing the 6-pounder was no longer powerful enough to defeat the heaviest German tank (the new Tiger), so the British Army dropped its requirement.
Despite this setback, the Molins gun was adopted by the Royal Navy and was fitted to many motor torpedo boats (MTBs) in the power-operated Mark VII mounting. In this form it used the shorter 43-caliber barrel of the Mk. 2 anti-tank gun and had a feed capacity of six rounds in the autoloader, plus one in the breech and another 12 in a ready-use rack on the mounting. The gun was a semi-automatic; the gunner had to press the trigger for each shot. It was probably the most powerful gun fitted to naval craft of this class and was regarded as very successful. Nearly 600 of these guns were made.
An additional 10 LCS(L)-2 was fitted with the Army’s manually loaded Mk. 5 gun in a Valentine tank turret, and these were used to provide close-in gunfire support for amphibious landings.
It wasn’t long before the Royal Air Force began looking at the versatile Molins gun for use as an airborne tank-busting weapon system to replace the 40mm-equipped Hurricane IID. The Molins replaced the four 20mm cannon below the nose of the Mosquito in a mounting that extended into the front of the bomb bay. This version of the weapon was known as the QF 6-pounder Class M Mk. I with Auto Loader Mk. III, and was based on the long-barreled 50-caliber gun.
The gun weighed 1,072 pounds (1,397 pounds with the autoloader) and was fully automatic with a rate of fire of about 55 rounds per minute. The ammunition supply in the autoloader consisted of 21 rounds, plus two additional rounds in the feedway. The rounds were fed by a combination of gravity and a spring-loaded arm and the four racks were moved into place in turn by an electric motor. The gun normally used the plain armor-piercing shot and had a high muzzle velocity of 2,920 feet per second.
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| The real life subject of Chris’ project. NT225 was attached to 248 Squadron based at RAF Pertreath. The Molins gun with autoloader can be plainly seen here. |
By the time the Mosquito FB Mk XVIII, popularly known as the “Tsetse,” had been developed, the RAF had lost interest in the anti-tank gun role, but Coastal Command eagerly accepted the aircraft.
Against U-boat hulls, it was calculated that the Molins gun would be able to penetrate when striking at an angle of 45 degrees or more at a range of about 1,400 meters, even through 60 centimeters of water. The gun/aircraft combination was extremely accurate, achieving a hit rate in training of 33 percent against tank-sized targets, compared with 5 percent for rocket projectiles.
The Molins gun in the Mosquito FB Mk XVIII was tested in the United States in 1945 against the nearest U.S. equivalent, the manually-loaded 75mm AN-Mk. 5 in the PBJ-1H Mitchell. This comparison made sense because the two weapons fired shells of about the same weight, and the 6-pounder and 75mm tank guns were all but interchangeable in the later British tanks.
The Molins gun impressed the Americans with its performance and reliability and was considered superior to the 75mm gun because of its much higher rate of fire. The researchers recommended that the Molins autoloader could be considered not just for conventional guns but also for recoilless weapons and spin-stabilized rockets, but the end of the war also meant the end of the line for the Molins equipment in automatic cannon.
However, the Mosquito Mk. XVIII had a career that was eventful in proportions that dwarfed its numbers. Only 19 of the aircraft were manufactured, and all but one of these were assigned to the Banff Strike Wing, principally serving with 248 Squadron.
The Tsetse arrived at a time when U-boats were no longer diving to escape air attacks but were instead remaining on the surface and fighting it out with ever-heavier batteries of anti-aircraft guns. The Tsetse gave Coastal Command a weapon that could stand off farther and pack a greater punch than the standard 20mm guns, or so it was assumed.
The Tsetses did indeed damage a number of U-boats and were credited with sinking one, but they also lent their powerful punch to attacks on German-controlled shipping along the Norwegian coastline and across the North Sea. The Molins gun could be devastating to merchant ships and the flak vessels that protected them, and in combat the Tsetses established an enviable record.
NT225 was a very good representative of the Mk. XVIII. It entered service with 248 Squadron around May 1944. The aircraft flew on numerous strikes along the Norwegian coast until Dec. 7, 1944, when the Tsetse failed to return from a mission to attack a convoy at anchor at Alesund. Two Tsetses were lost on this mission, the first to meet with significant Luftwaffe opposition. Flying Officers William Cosman and Leslie Freedman were lost after an attack by the Bf 109G of Lieutenant Heinrich Freiherr von Podewils of JG.5.
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| Another image of NT225. The Molins gun can be seen poking out from under the nose. The anti-shipping gun replaced the four 20mm cannon. |
Many years ago, I toiled over an Airfix Mosquito in an effort to build a Tsetse. While the Airfix kit is good even today, sometimes an individual model is just cursed. Anything that could go wrong did go wrong, from the cockpit to the paint to the propellers. Nothing worked, despite my best efforts. This model was so benighted that, on the night my club held its “dogfight” contest for models that didn’t come out right, one of its wings popped off while I was holding it and damaged my latest model! Still, I had affection for the Mk. XVIII, and when Tamiya and Hasegawa each put out new 1:72 Mosquitoes I started thinking about building a Tsetse again. I decided upon the Tamiya kit primarily because in the space of six months, I won three in club raffles! The kit’s engineering is similar to that of the Tamiya 1:48 kit, with a carry-through spar supporting the wings. The top of the nacelles is molded to the top wing and breaking at a panel line; and the nose joins the fuselage along a seam that is largely hidden by the wing. It’s a thoughtfully engineered model.
My first step was not the cockpit, as is usually the case, but the wheel bays. I made blank-off plates for the front and rear of the bays and added squares of .005 styrene sheet to blank off the two ejection-pin marks in each side of the bays - cut to match the squares formed by the stringer and former detail. I used copper wire to add detail to the top of the bay, and some styrene strip was added for structural detail. The nacelles were then cemented together and test-fit against the upper wing, yielding a very encouraging result. Builders of multi-engine aircraft are used to doing lots of work to join the nacelles to the wings, but there would be little of that here!
The wings were assembled once the landing lights had been inserted into each lower wing. The nacelles were added next, and they fit well except for the flat, pointed area extending behind the wing, where large gaps were present. These were very easy to address, however, and filling them with styrene bits and superglue followed by a few minutes of sanding cleaned them up. I also used an engraving bit in my Dremel tool to add a little depth to the carburetor intakes; the kit has the openings to these molded flat, but a few minutes of careful work created the impression of openings with in-scale edges.
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| After painting and masking the invasion stripes, Chris painted dark green freehand over the light sea gray for a soft edged camouflage pattern. |
The kit cockpit was nice, but I opted to use the Aires cockpit instead. This included a resin door for the forward fuselage; however, the sidewall piece provided for the starboard side where the door would go had no guide as to where to cut. This raised the prospect of a mismatch between the kit fuselage and the resin part. Instead of devising a way to true up the two parts, I started looking at the sidewall in relation to the kit fuselage. I quickly realized that I could cut the resin away just below a run of wiring and then down along the flare gun holster; effectively going around the door, and the raised features would prevent this cut from being seen from above. This allowed me to cut the door off the fuselage with a Dremel tool and an assortment of small bits, using the kit panel lines as a guide.
Next came the assembly and painting of the Aires interior parts. These included a series of sections that made up the stepped floor and radio shelf, two sidewalls, a control panel with a photo-etched control panel, a set of radios, the pilot’s seat and the observer’s armored seat back and photo-etched seat belts.
All the parts were painted with Testors interior black, followed by an airbrushing of RAF interior gray-green. The navigator/ observer’s seat was painted burnt sienna with a black wash to replicate leather, as was the back cushion on the separate seat back. The wiring was painted a yellowish-tan color to replicate the colors found in my references, and the flare cartridges below the navigator/observer’s seat were painted their appropriate colors. The pilot’s seat was painted interior gray-green and the cushions were painted a dark gray. I painted the seat belts for both seats, which were provided as photo-etched parts, and carefully added them to both seats. The radios were painted using the excellent photographs in the SAMI book on the Mosquito as a guide. The radios and pilot’s seat were then set aside. I had some problems with the complex photo-etched rudder pedals; eventually I resorted to stealing the pedals out of the hulk of the old Airfix Mk. XVIII!
The fit of the major structural parts of the resin cockpit was troublesome, to say the least. I spent a lot of time sanding and test-fitting them to the fuselage, because they were simply too big for the space they were intended to fit. That combined with the multi-part nature of the cockpit made for a tedious job. The same went for the control panel and instrument shroud. The panel was a photo-etched part with an acetate backing for the instruments, and the shroud replaced the out-of-scale kit part and included the gunsight and other prominent features inside the windscreen. This part was nicely detailed but fit poorly, so judicious sanding was needed to get the part to fit without causing a visible seam inside the cockpit.
Once the major cockpit pieces were re-sized and positioned into one of the fuselage halves, things became easier. The pilot’s seat and radios went into place with ease, and I was pleased to see that not much of a gap was left inside the fuselage. The resin door was painted and set aside for future addition.
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| The aircraft version of the Molins gun with autoloader (top). The business end of the Mk. XVIII “Tsetse” with the Molins gun (bottom). |
With the cockpit ready, I prepared to join the fuselage halves. First, however, I had to cut off a section of the lower fuselage in order to accommodate the Molins gun nose from the Airfix kit, which provides plates for both the 20mm cannon nose and the Molins gun nose. The Airfix part is slightly longer, however, so I had to cut away a section of plastic from the Tamiya fuselage halves and make a notch in the bomb bay doors to accommodate the big gun. The fuselage went together next, followed by the bomb bay doors and the nose gun plate. Once this plate was added, I sanded away the overly-heavy rivet detail and the inaccurate keg-shaped breech fairing, both vestiges of Airfix’s attempt at a Molins gun arrangement, and added a new breech fairing from, of all things, an Italeri RB-66 ECM blister. According to photos, it’s a very close match. After much sanding, I rescribed the lost panel detail on the nose and bomb bay doors.
Next, I added the nose and the four .303 machine gun barrels. Most Tsetses eventually had two .303s removed, but I liked the look of the four guns bristling from the nose. I next made my biggest mistake of the project: I relied on the SAMI book on the Mosquito for the details of my Tsetse. I painted the exhaust stacks with a darkened mixture of burnt sienna and glued them in place, then added the exhaust shrouds as the book instructed in its guide to the variants. A little later, I started looking for photos of a specific aircraft to model, and I found that NT225 was particularly well documented and settled on that aircraft. Unfortunately, NT225 did not have shrouded exhausts, so I pried them off and removed the stacks for addition after painting. I had to scrape and sand the points where the shrouds joined the nacelles, grumbling the entire time about not working from a photo from the beginning.
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| Chris used the nose from his Airfix Mosquito kit and a Aber turned aluminum 57mm Russian anti-tank gun for the Molins gun barrel. An Italeri RB-66 ECM blister was used for the breech fairing. |
The wings went on with absolutely no fuss. I brushed a light layer of Mr. Surfacer 1000 over the seams, then removed the excess with a cotton swab dipped in Mr. Thinner. That was all that was needed to perfect the wing root joint. I drilled small holes in the wing tip lights and then painted the inside faces silver followed by a small drop of the appropriate color into the hole to simulate the bulbs. These parts were superglued into the wing tips, sanded, polished and masked. I also drilled out the signal light positions under the tail in advance of the addition of MV Lenses of the appropriate colors.
I painted the propellers next, airbrushing the yellow tips first, then masking them and painting the blades a semi-gloss black. In fact, I painted propellers for several planes at once; I think I had five Mustang propellers, a pair of HU-16 Albatross props and a T-28 propeller on the table all at the same time! I find that mass producing parts like wheels and propellers can be a productive use of painting time and less wasteful of paint than just painting one or two props in a session. The spinners were painted ocean gray, as were the backing plates, and the propeller/spinner assemblies went together and were set aside for future addition.
Next came the tail. The horizontal tailplanes required only a small bit more filler than did the wings, but I did slightly reshape the vertical fin as the kit fin is slightly too tall. Close inspection of photos helped in this. I then rescribed any panel detail I had removed, and I suddenly had a very Mosquito-shaped object on my workbench!
The one disappointing area in Tamiya’s kit is the canopy. One side window is provided as a separate and difficult to fit part; moreover, the entire canopy is just oversized enough to cause a sloppy fit. I joined the canopy to the fuselage first with white glue, then with a small amount of superglue, followed by some nerve-wracking sanding. I was afraid the sanding might break the canopy free - which it did on two occasions, forcing me to go back to the start and repeat the process more carefully. Once the canopy was on, I faced the equally nerve-wracking process of masking the canopy with Parafilm M and the use of a new scalpel blade.
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| While the Tamiya kit was very good over all, Chris found the canopy to be over-sized and a bit troublesome to get a proper fit. The port side of the nose it painted is if it were a replacement part from another Mosquito with a slightly different painted scheme. |
With all of the major parts in place, I started work on the finish. One of the more striking things about NT225, and about Banff and Dallachy strike wing aircraft in general, was the presence of invasion stripes long after such markings had been removed from most aircraft in Great Britain. My process for painting these markings is simple, but may seem counter-intuitive to many. I paint the invasion stripes first, then mask them off and apply the rest of the camouflage to the model. The same goes for leading edge identification panels, theatre bands and other large markings; I find that painting them and masking them is easier than aligning and applying decals.
I start by painting a band of flat white over the entire area of the invasion stripes. It’s a good idea, whenever possible, to paint light colors first. The white stripes that would remain were masked and Testors interior black was shot over them to form the distinctive invasion stripes. Masking the wings is very easy, but I had to use very thin sections of tape cut with a straightedge in order to conform to the compound curves present on the rear fuselage. Once the paint had dried, I stripped off the masking to check my work and promptly masked it all off again in preparation for the application of the camouflage scheme, with the exception of small rectangular sections on the tail. Photos showed that the serials on both sides of the fuselage had been masked over before the application of the invasion stripes, so these open panels would get the camouflage, followed by the serials during decaling.
Roy Sutherland has spent the last several years trying to debunk the idea that large rubber mats were used to apply RAF camouflage schemes. I personally believe these mats were used in North Africa to help inexperienced crews apply improvised theatre camouflage; but I agree with Roy that factory camouflage had a soft edge during the war years. With that in mind, I shot the entire model with a coat of light sea gray and lightly traced the appropriate RAF camouflage pattern with a pencil. I also masked off the horizontal tail, which was left uncamouflaged, according to photographs. Feeling confident in my abilities with my Paasche VL, I freehanded the scheme and achieved a fairly tight line on the borders between dark green and light sea gray.
Photographs showed that NT225 had an odd paint anomaly in the nose area. Apparently, the aircraft suffered damage and a replacement nose panel was substituted, because the port side of the nose had a hard line in the camouflage right along a panel line. For a moment, I entertained the idea that the replacement had come from a nightfighter Mosquito and I could paint the nose black; however, it seems much likelier to have come from another Banff Strike Wing plane that had a slightly different application of the camouflage applied.
I masked off the panel line and applied a little darker mix of dark green, matching the photos. Once all the painting of the main surfaces of the aircraft was finished, I took off the invasion stripe masking and shot a coat of water-based Varathane thinned 50-50 with water to provide a glossy base for the decals.
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| The code letter “O” proved to be a difficult decal to acquire. Chris solved this problem by cutting the tail off a two-part “Q” decal from his Hasegawa Spitfire Mk. VIII kit. |
The decals, or at least one of them, proved to be a challenge. The roundels and serials were taken from an assortment of sheets for the Tempest V. The data decals came from the Tamiya sheet and went on very nicely. The only big hang-up was the code for this particular plane: a single “O” on each side of the fuselage. This serial was RAF insignia red, with a white surround.
As simple as this sounds, this marking was almost impossible to find. The search was exhaustive; among the candidates were nose numbers in 1:48 for a MiG-29. While some of these may have gotten close, they simply didn’t satisfy me. Ultimately, I stumbled on a solution by cutting the tails off the two-part “Q” decals included in Hasegawa’s first boxing of their Spitfire Mk. VIII. This marking was provided as two decals - one white and one red - which was the only thing that made the surgery needed to form a pair of “O”s possible.
Again, contrary to my expectations, the kit decals went on without any problem. Perhaps the largely panel-free surface of the Mosquito provided an assist in this department!
Once the decals were in place, I shot a second coat of thinned Varathane as a sealer and applied a dark gray “sludge wash” to the entire model. This involved using a gray watercolor paint mixed with water and a few drops of dishwasher liquid to provide “sticking power” in the nooks and crannies. Once the wash had dried, I wiped the excess off with a moistened paper towel. I mixed up a 60-40 mix of lacquer thinner and Testors Dull Cote and applied this as a flat coat; thinning the Dull Cote ensures a smooth texture and a thin application that is resistant to the yellowing that Testors’ flat coat is notorious for. Once the dull coat was applied, I took the masking off the clear parts and was rewarded with a fairly clean application of the canopy framing.
Since my Mosquito was supposed to be a strike wing veteran, I added some gun blast effects to the nose in the area that would be occupied by the Molins gun; along with some exhaust staining behind the eventual location of the exhaust stacks, with gray, brown and black pastels. Only after the exhaust stains were applied did I add the stacks themselves. During this stage I also added some black wash to the carburetor.
The landing gear are small models in themselves. Each consists of a two-piece wheel and tire, two struts, a retraction strut, a mudguard and an oil tank, all of which fit together remarkably well. I drilled out the lightening holes on the mudguard’s mounts using a pin vise, but such common add-ons as brake lines were already present on the parts. I pre-painted the struts with a mixture of Testors aluminum and metallizer buffing aluminum; the lacquer-based metallizer helps the aluminum paint flow off the brush better. Details like brake lines and the black shock-absorber section of the struts were also painted before the parts were assembled over the wheels. The oil tanks were painted a burnt sienna color with silver mounting straps and added to the main gear. The tail wheel was painted and installed, and the mains went into place with very little effort.
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| NT225 and the other planes in it’s strike wing wore D-Day invasion stripes long after most units were having them removed. NT225 was lost on December 7, 1944 when it failed to return from an attack on a convoy at Alesund. |
Once the model was on its gear, I mounted photo-etched screens on the carburetor intakes using bits of fine wire to replicate the standoff the real items have. The props came next. I added some visual interest by applying tiny drops of black ink with a .005 Rapidograph pen to the perimeter of the spinners near the propeller cutouts and smeared the ink backward with a moist cotton swab, replicating the oil leakage seen in some Mosquitos. The finished props, with their vinyl bushings, were pushed onto the prop shafts.
The final detail: the Molins gun! Vladimir Yakubov, the club’s resident Soviet 1:72 armor expert, picked up an Aber turned aluminum 57mm barrel intended for a Russian anti-tank gun. This was cut down, painted, drybrushed and cemented into place. The final addition was the crew boarding door, which had been painted and set aside much earlier.
So, at last, I had the Mosquito Mk. XVIII I had wanted in my collection for so long. The Tamiya kit is so well thought out I’m already entertaining ideas of a 1:72 Sea Mosquito TR.33, a two-stage photo reconnaissance version or a somewhat out-of-the box Mk. VI fighter bomber. I still have two more kits, so a swarm of Mosquitoes might be in the offing!
[More photos of Chris’ Mosquito model can be seen at - http://svsm.org/gallery/cbmos]
Chris Bucholtz has been building models since 1973 and has been a member of SVSM since 1986. His interests include 1/72 scale aircraft of all types, but specifically World War II and subjects whose pilots or crew he has met.
