MPM 1/72 Fokker G.I Mercury


I'm not much into WW II aircraft, except for the Me 163B and two Dutch aircraft: the Fokker G.I and the Curtiss-Wright CW 21B. When MPM released its 1/72 injection moulded kit of the Fokker G.I around 1997 (catalog number 72-034), I bought it. I like the way they executed the kit: the completely clear fuselage halves was an excellent idea. The rest of the kit is typically MPM: a bit rough, no perfect fit, and some photo etch. Around 1999 MPM issued a second version of the kit, packaged in a black and white box, that has additional resin detail parts.



References

The next step after buying the kit is gathering references. The best G.I source so far is Hugo Hooftman's 'Nederlandse vliegtuig encyclopedie: Fokker G.I' that contains some 250 photographs (second and extended issue shown, first issue had a black and white cover photo, and 160 photos). Unfortunately this book is pretty rare these days. I had the luck that a friend had a copy that he donated to me; thanks again, Koen! I also laid my hands on extremely nice drawings by NVM (Nederlandse Vereniging van Modelbouwers). I attended a presentation of the Stichting Fokker G.I (Fokker G.I Society), and I was very impressed by their activities. They are slowly uncovering lots of information on the G.I. They brought some of the stuff they had found, including photographs from Denmark that showed the construction of G.I's. Edwin Hoogschagen's site about the Royal Netherlands Air Force had lots of pictures and provides a historical background of the aircraft. It even included a listing of the achievements of nearly all individual G.I's. However, the site is currently off-line because of reconstruction. You can mail Edwin to ask when it will be up again.

Other references (that I don't have) are Profile number 134 by Bart van der Klaauw (1966), and three articles in Air International (October, November and December 1974, Volume 7 numbers 4, 5 and 6) of which the second includes a cutaway drawing. Curiously no writer is mentioned. The magazine MIP of IPMS-NL had articles on the G.1 in its 3/78, 4/78 and 1/79 issues. A more recent source is the 5 January 1990 issue of Aviation News van 5 jan 1990. The 'Warpaint' section contains a large number of drawings, detail drawings and paint schemes, all in 1:72 scale, made by Frenchman Hubert Cance (see his website). Lastly, 'The Last Of The Fightings Fokkers' by Karl Toll, covering both D XXI and G I was published in the January 1982 issue of either Wings or Airpower magazine, and it contains some detail drawings of the landing gear and bomb bay.

Also worth mentioning here are the newsletters that the Stichting Fokker G.I publishes. They often contain very interesting sketches and drawings. Compilations of these newsletters are sold by the Stichting at Dutch airshows, and most likely can be ordered via the website too.

The ultimate Fokker G.I reference will be the book that the Stichting Fokker G.I is working on. Currently (summer 2006) the planned publication date is summer 2007.

Engineer Pim Pouw, member of the Stichting Fokker G.I, makes 3D drawings in Catia of the reverse engineered Fokker G.I. He shows a large number of his drawings of the digital mockup on his site. A fantastic reference!



Model quality

The MPM G.I is typical for limited-run kits: medium-quality injected parts (some mold damage being visible) with relatively soft detail, no perfect fit, some photo-etch for the cockpit, and nice decals. The engines are rather bad representations of the Mercury, since they have two pushrods in front of each cylinder, yet the Mercury had them running together through one central tube. The props are rather bad, firstly because of the crude detailing of the hub and inaccurate blade shape, secondly because they are handed, which the real ones weren't! The decal set is rather small, as usual with MPM, and contains decals for only one Dutch aircraft (314, with pre-war round roundels instead of orange triangles) and peculiarly a German captured G.I (coded '97').

A later 'Upgraded' issue included a resin set, with both front and rear cockpits, two seats, control column, and two Mercury engines with individual cylinders, and identical decals. The resin engines apparently are exactly to scale, and subsequently do not fit their cowlings, made of non-scale thickness plastic. Very considerable sanding of both the cowling interiors and the cilinder heads is necessary.



Model accuracy

Now about the accuracy. This is a confusing part, since no definitive drawings exist. I'm slowly (very slowly) discovering more and more about the model's accuracy, so bear with me. The following remarks are incomplete and could need revision at a later point. Also, I haven't seen any reviews in Dutch modeling magazines, even though this model was very welcomed by Dutch modelers. I started to compare the kit with the drawings I had back then, but found too many differences in the drawings to be sure. I decided to stop there, and build the kit more or less as it is and have fun. If I want a perfect example, I first needed to be sure the drawings were OK, and back then I wasn't so sure about that. So I started construction, as detailed below.

I looked again at the model's accuracy after I put the lower fuselage and wings together. The fuselage pod look somewhat strange to me, and that pod became the focus point of my research. I thought its diameter appeared too large compared to the engine nacelles. They almost line up at the lower sides, whereas pictures of the real one show that a G.I can make a belly landing without any damage to the fuselage pod. Another thing was the exterior shape of the cockpit. Having seen a built-up model I would say this part is too wide. This is possibly caused by the fact that the fuselage isn't circular at that point, but more of a square. Since the cockpit sides are tangential to the fuselage, this causes the whole cockpit area to be too wide. The sketch shows what I mean, but it is not a scale sketch!

After a long time of searching for the answers, I now think I found them. The good news is that the overall dimensions of the fuselage pod (width, height, length) are within 1 millimeter of the dimensions shown by the 1998 'Stichting Fokker G.I' drawings. The bad news is that the fuselage should be round indeed, and not squarish like the MPM kit. Unfortunately, that error is almost impossible to correct.

The source of this error was also found: it strongly appears the MPM model is based on a Czech (or Slowak) drawing shown on page 3 of Hooftman's book, drawn by Zdenek Kaláb (Kb signature). The drawing has four fuselage cross sections, and they clearly have flat sides, just like the MPM model. Another clue that this drawing was used for the MPM model is the elevator. The drawing shows 5 cut-outs on the leading edge, just like the model has, but the real aircraft doesn't have them. Other drawings don't have these cut-outs either. It will be interesting to compare this drawing and the 1998 'Stichting Fokker G.I' drawings. It could give us a good analysis of the MPM model. More news to follow.

Below is a comparison of the fuselage dimensions of the Stichting G.I drawings (scaled back to 1/72 scale) and the MPM, CMK and Rareplanes models (CMK data courtesy of Sidney de Koning).

Item

Stichting G.I     MPM         CMK     Rareplanes
Fuselage width @ cockpit rear bulkhead ~17.7 17.1 16.3 ~15.0
Fuselage height @ cockpit rear bulkhead    24.4 24.7 24.7 ~19
Fuselage length 90.2 92.2 89.1 89

This data suggests that the Rareplanes fuselage is considerably undersize, and that the overall dimensions of the MPM and CMK fuselages are close to the best data available. However, the CMK fuselage has a more correct fuselage cross-section it seems (see photos below). Fellow G.I builder Sander van Kreijl remarked that the MPM lower fuselage contour in side view is too massive, the fuselage should taper more, giving a more elegant nose.

The diameter of the MPM nacelles was found to be correct. They aren't round, but that can be solved easily by shimming the glue joint. But I believe the vertical position of the nacelles is not correct: they are placed too high on the wing. This explains the limited 'ground clearance' of the fuselage pod. But it is close to impossible to correct this problem.

I still haven't measured the overall dimensions of the model. I blame the configuration which makes it difficult to tape it together :-)



Other models

Four other Fokker G1 models in 1/72 scale have been identified. The resin models were issued under a number of brand names.

Model 1: Rareplanes vac

Rareplanes issued a vacform model in March 1978, with catalog number 4011 or RP4011. It has a much smaller fuselage pod than the MPM kit. I briefly studied it, and compared to the 1998 'Stichting Fokker G.I' drawings, the fuselage pod is 15% too narrow and 22% too low, but the length is more or less correct. Overall, the fuselage pod looks very small compared to the MPM pod.

Model 2: Airmodel vac

Airmodel from Germany issued a vacform Fokker G.I, kit number 337. Peter Ibes reports that he built the model somewhere between 1990-1995, and he kindly supplied the following scans and information. The kit allowed construction of both the G.I Mercury (G.IA) and G.I Wasp (G.IB). The Mercury version could built using the integral wing+fuselage upper and lower halves, for the Wasp a separate fuselage pod was provided.

This model was reissued late 2009 with improved clear transparent parts, but still no decals or resin parts. Wheels, engines and props from a Frog/Novo or Airfix 1/72 scale Blenheim are recommended. The Airmodel website has a photo showing the parts.

Model 3: brandless Czech resin

A brandless resin G1 was produced by Czechoslovak modellers in the communist days and they were probably only used as trade material with pen-pals. Resin models of a Fokker D23 and a Fokker T8W were made by the same modelers. Fellow IPMS-NL member Jos Gouman owns two versions of the model, identified as 'Fokker G-1' and 'Fokker G-1 a/b' respectively. Jos describes them as cast as almost one-piece models with separate engine cowlings, props and landing gear parts, mostly of mediocre quality, and in case of the landing gear of insufficient strength. Cockpit and rear gunner position are vacuum formed parts, but the center fuselage windows are just represented as depressions to be filled with paint, or alternatively cut open and filled with Kristal Klear. The 'Fokker G-1 a/b' version has complete vacform fuselage halves (split horizontally) included as an extra, for which the resin fuselage must be removed. The engine cowlings also show differences: in some kits the engines are integral, in other the cilinders are separate. The meaning of the number '444' on the bag is not known. By the way, if you are interested in obtaining this model, please contact Jos Gouman, he has a few left over. Shown here are two of Jos' models.

Interestingly, the model has commonalities with the MPM model. The overall dimensions and shapes are identical, the horizontally split fuselage of the 'Fokker G-1 a/b' version is repeated in the MPM model, and the resin model's forward fuselage has the same shape problem as the MPM model. The Fokker T8W mentioned above also appeared as an MPM model, and it too has a lot of similarities. It is likely that the resin models served as masters for the MPM injection moulded models.

Likely the same model was offered on Ebay. The auction description mentioned "Rare CzechMASTER epoxy resin casting with detailed interior. Manufactured by my friend in Prague in the 1980s." Mysteriously, the single-piece casting now has two colors.

Model 4: Czech Master's Kits & IPMS Master Models & Aeromodell & Mareksa resin

Czech Master's Kits issued a resin model in the mid-eighties (catalog number 74, with '72' hand-written below it). It is likely based on the brandless resin model, but it is broken down in parts. The same model was also sold from 1991 to 1994 by the 'IPMS-NL Shop' under their own label, IPMS Master Models, possibly without the instruction sheet. The model has a vacform fuselage pod that appears more accurate than the MPM fuselage, at least the windscreen of the cockpit is narrow as it should be. The left three model photos were made by Rene Erhart, the CMK instruction sheet and the right photo were provided by Sidney de Koning. The latter shows the better cockpit cross section and windscreen shape of the CMK model. Apart from the version shown here with parts in green resin, there is also a version with grey resin parts.

The same model was also sold by German mail order company WK Models under its Aeromodell brand with catalog number WK09. John Burns' PAK-20 book mentions "Many of the 1/72 resin-cast kits in the line probably came from Czechmaster molds". The G1 is clearly among these. Note the different resin color. Another model had green resin parts, and the cover sheet of the box was in yellow. Lastly, I've also seen a version which was 'packaged' in a printed yellow A4 sheet, folded double and stapled. Its parts were dark green.

John Burns' PAK-20 book also reports that the Polish manufacturer Mareska (operational between 1996 and 1998) issued a resin Fokker G1, and reports "Many (if not all) of these kits are also listed under Czechmaster and probably served as master molds for a variety of other European kit companies".



Aftermarket items

To replace the incorrect props, possibly Airfix Blenheim props or Aeroclub white-metal props will do the trick. I found two Aeroclub Blenheim props: P021, description '2x De Haviland (Hamilton-Standard) 3 blade 2 position bracket 11'6" [3.51 m] diameter R/H' for 'Bristol Engines - Blenheim/Beaufort' and P098, description '2x De Havilland two position BKT (bracket?) three blade 10' [3.05 m] diameter R/H' for the Bristol 142 which was a civil transport from which the Blenheim bomber was developed. The MPM props are 11'1" / 3.38 m. The Stichting drawings don't give a figure for them, but I measured 10'9" / 3.28 m in the drawings. Plenty of figures, take your pick!

Fellow modeler Jan Verwoerdt came up with the definitive answer to this question in June 2004: according to Fokker's G.I handbook (that was never issued to the LVA by the way), the Mercury VIII engined G.I had props with a diameter of 3.28 m, which translates into 10'9". Ten points for the Stichting drawings! But neither of the two Aeroclub props will be completely accurate.

Propeller news in 2014:SBS Model from Hungary issued resin propellers for the Airfix Bristol Blenheim (SBS catalog number 72022). They are possibly usable for the G.I.

The vast catalog of Aeroclub also contained several Bristol Mercury engines. Aeroclub is currently dormant, but a full list of engines can be found on Joe's Model site. It contains three Mercuries:

Engine news in 2005: Vector from Russia (Podolsk) issued a highly detailed and perfectly cast resin Bristol Mercury in both 1/72 and 1/48 scale. Linden Hill (USA) has a page with information, and the 1/48 engine was reviewed on Hyperscale. The 1/72 version is rather simpler than the 1/48: it just consists of a crank case plus gearbox and ten cilinders, and the cilinder lack the characteristic single pushrod tube. As with the MPM resin engines, the characteristic baffles are absent. Also, the 1/72 engines are labeled as 'Bristol Mercury/Pegasus', but the cilinders are those of the Mercury version, the Pegasus cilinders being much longer. The kit lacks instructions on assembly, painting and detailing.

Engine news in 2012: Radial Engines & Wheels 72 from the Czech Republic issued a resin 1/72 Bristol Mercury (72016). The engine is cast in one piece, in contrast to the separate cilinders and crankcase of the Vector engine. From a first photo the gearbox in front of the crank case looks better, and the cilinders have a pushrod tube and clear exhaust ports, which helps in getting the tubes to the exhaust collecter ring right. There's a brief review on the IPMS Germany site.

Engine news in 2014: SBS Model from Hungary issued a resin 1/72 Bristol Mercury in two different sets: 72015 for the Airfix Gloster Gladiator, and 72017 for the Airfix Bristol Blenheim (two engines). Each engine is cast in 22 separate resin parts. There's a review on Aircraft Resource Center.



Wing-fuselage assembly

Due to its configuration and lack of mountings tabs or locating pins, this model isn't easy to assemble accurately. I decided for an approach that deviates from the instructions, and is probably more work, but I think the end result will be better. If you sandwich the finished fuselage pod between the finished wings, there's are considerable risk that the the pod is rotated or at the wrong incidence (pitch angle), or the wings are not mounted at the same level. I wanted to start by gluing together either the upper or lower wing halves and fuselage, and work from there. This allowed good alignment of the wing's dihedral and sweep, the installation of spars (although not really necessary for strength I think) and a good alignment of the fuselage pod with respect to the tail booms. Lastly, the spars would offer me a good starting point for the cockpit interior that I was planning to scratch build. MPM in the mean time has reissued the kit with resin cockpit and engine parts. Possibly I will use some of these parts, but I still intend to largely do the cockpit myself.

After some considerations I decided to use the lower half as the starting point. First problem was the alignment of the fuselage and wings. MPM has scribed a wing contour on the transparent fuselage halves, which would align the horizontal break in both the fuselage and the wings. I had my doubts about that: it looked like the gunner's turret would be too low with respect to the tail booms. After a lot of measurements I'm still not sure, but I decided to bring the tail cone up 2.3 millimeters. It looked like the position of the leading edge is OK. Gluing wing halves and fuselage together then became much more difficult. I decided to build a simple jig from plastic card, shown below. I used 2 mm card, built up with 0.3 mm in places that mattered.

Before putting them in the jig, I thinned the trailing edges of the lower wings halves. The jig allowed the lower fuselage to be canted slightly (it rotates around the wing leading edge), while the wing halves were kept horizontally. The 'wing sweep' (none on the center section) was controlled by the stops at the leading edges. It turned out that a small spacer was needed between the rear fuselage and the trailing edge to keep the wing sweep at zero. The Milliput filling around the spacer can be seen in the picture. I hope this will have no consequences for the fit of the horizontal tail between the tail booms!

I used some Milliput to reinforce the joint between the wing halves and the fuselage. Then it was time to put in the spars. Since I was building the kit 'optically', I found the position of the front spar by looking at the rear panel line of the canopy; the panel lines on the wing do not agree with that. The position of the rear spar was determined by looking at the rear windows. I cut out small notches in the clear lower fuselages accordingly. The spars were built up from 1 mm plastic card, made to fit in inside the wing halves. Inside the cockpit they were thickened to the real thickness of the wing. Pieces of 0.25 mm card covered the laminated spars. I also put in a small partial bulkhead just in front of the front spar. It is the forward bulkhead of the bomb bay (yes, it's usually called bomb bay!). To have a starting point for my scratch built interior, I glued a piece of card in the forward fuselage. It sits too deep to serve as the cockpit floor, but it is a start.

This is what it looks like with the upper fuselage and wing halves added. The upper fuselage halve also needed small notches to make room for the spars. Don't let the painted window on the nose fool you; it is an experiment to find out the best technique for painting the interior without its light grey color showing on the outside.

Here the assembly stalled, since I thought the fuselage pod was too large in relation to the engine nacelles. Now that this turned out to be not true, construction can be resumed.



Tail assembly

Now that the situation with the fuselage was clear (but not solved), I continued construction of the model. My biggest worry was the tail assembly. Typical of a limited run kit, the fit of the parts is pretty vague, and a careless modeler can easily end up with a severely mis-aligned model. I decided to take no risks here, and over-engineer things a little. First I wanted to achieve a perfectly square connection between the tail booms and the horizontal tail. I drilled holes through the tail booms and into the horizontal tail, using squares to ensure alignment. I then glued pins in the horizontal tail plane, as shown in the photo. These pins were plastic initially, but due to the tight fit they didn't last long. They were replaced with steel wire later. Note that the pins' primary function is to ensure proper alignment, allowing assembly and disassembly during construction. I don't think they are necessary from a strength point of view.

With these measures, the whole tail assembly was nicely square, without play between the parts. Time to test-fit them, a moment which I feared because of my slight change of the wing sweep, as explained above.

The result was surprisingly good: the tail booms connected nicely with their 'roots' on the wing. And for the first time I saw the complete model, which is always an inspiring moment!

As you may have noticed in the photos above, I removed the tail's control surfaces. I had never done this before, but it wasn't too complicated. I started with the left rudder, which was easily cut off using a razor blade saw. The hinges were created from pieces of plastic card, and the job was done!

The elevator was a completely different story however. From the five notches moulded in the leading edge of the elevator, I concluded it had five hinges, and that it the leading edge would remain (partly) covered by the trailing edge of the horizontal tail. I cut off the elevator, give the tail plane a 'lip' from my smallest-size plastic strip (just visible as a white line), and built up a partial leading edge on the elevator. And only then I started looking for photos of the real thing. Note that this is definitely the wrong order :-) And what did I see: no notches at all, and the leading edge of the elevator projecting above and below the tail plane when it was deflected! This discovery helped to convince me that MPM used the Zdenek Kaláb drawing, as explained above.

After this discovery, I removed the strip from the tail plane and the built-up leading edge on the elevator. Measurements in the Fokker G.I Stichting drawings showed that I should sand the original leading edge round, without any extension. About a year later I found out the truth about the elevator hinges, courtesy of the Stichting Fokker G.I people manning a stand at the Volkel 2004 airshow. The elevator did have five hinges, but due to specially shaped hinge brackets and an unusual elevator structure, they don't show on the top side. Although the drawings did not show it, there must have been slots in the lower side of the elevator, and this is how I will finish my elevator.

I am working on the right rudder now, repeating the work of the left rudder. I also rescribed the left tail boom. The real tail boom is built up from 7 sections, with a total of 15 frames (visible because of the rivets). MPM correctly engraved 7 panel lines, but the panel lines on the inboard and outboard halves did not line up. Since they were also wrongly positioned, I decided to do them all over.



Colors and markings

Probably the best source on the colors of the G.I is 'De geschiedenis van Camouflage en Kentekens op de vliegtuigen van de Nederlandse Strijdkrachten' by John Greuter, Max Schep, Luc Boerman and Joke Bossong, Bonneville, 1997. This book reports that no paint chips survive, only some models that were painted at the Fokker factory with the original paints. These give a reasonable idea of the colors. The G.I was painted brown overall with sand and green patches on the top surfaces. There was one scheme, but in two variations, with the green and sand switched (used on 300-317 and 318-335 respectively). The following matches are reported:

Another interesting source of G.I colors was published in 'Periodiek Informatie Bulletin (PIM)' by IPMS-NL, issue 1983-5. In a letter by P. van de Dijk from Utrecht, he recalls the colors he saw on LSK aircraft before the war at Soesterberg. Working from memory, but having tested his memories on Fokker D21 and G.I models, this modeler reports:

The MPM instructions suggest the following colors:

A different set of matches was found on rec.models.scale, posted by Jim Maas in 1997. It's colors are somewhat closer to the first set of matches, compared to the MPM colors:

I am a long way from the painting stage, and I haven't studied the FS matches in detail yet. On first inspection, the first set of colors is rather different from the other two sets. The green is very dark, the sand is not a tan color (it has little yellow in it, and a bit of green), and the brown has much less red in it. The model's appearance will be quite different from the MPM and Jim Maas colors, and very different from the MPM box art or the book cover shown above. The cockpit color is not confirmed yet, but nearly everything points to light grey. Other Fokkers from that era also used that color, and cockpit pictures show a light color. I will use light grey with very few doubts.

In March 2005, White Ensign Models announced that it will produce the G.I (and D21) colors for MW Models in the Netherlands, now Naval Models but the site doesn't list the paint. The colors are coded as follows: ACD 01, LVA Camouflage Groen (green gray), ACD 02, LVA Camouflage Bruin (dark brown), and ACD 03, LVA Camouflage Beige (light sand). Luchtvaart Hobby Shop started selling them in 2005. Here's a message from White Ensign Models about the paint.

A couple of days after I bought the White Ensign Models paints, *possibly* a spanner was thrown in the works. According to a member of the Stichting Fokker G.I, the colors found on recovered G.I parts was different from those reported in the 'Camouflage en Kentekens' book. He wasn't completely sure though, but I found it worth mentioning here.



Decals

I haven't looked good at the MPM decals, so I can't say whether they are correct. The scan shown below is courtesy of fellow G.I builder Sander van Kreijl.

For aftermarket decals, there are/were two choices:

I designed some decals myself using CorelDraw, for Alps printing. Apart from the serial numbers I want, I made a decal for the data block seen on the tail boom of most G.I's. This decal is not included on the MPM sheet, and only partially and unreadable on the Dutch Decal sheet. It took lots of modifications on an existing font to make something that looked like a hand painted 1939 font, but I think it looks really sweet now. Only problem is that I hadn't realised how small the printing would be. It is to be seen whether my sweet data block is readable in 1/72 scale.. Some of the figures in the data block are guestimates! Also, my interpretation of the wording differs in detail from that of Jan Broos in the NVM drawings. I used 'Benzine' instead of 'Brandstof' and 'Geschilderd' instead of 'Datum'.

Shown below are the actual decals. Their quality may look mediocre, but remember how small the lettering is: only 0.25 mm (1/100th of an inch) high, and still readable!! I had to scan the decals at no less than 1200 dpi to show it, and then crank up the contrast and reduce the brightness to make them better visible. This explains the spotty background color. Alps decals are fantastic!



Bristol Mercury engines

To reduce the loading time of the current page, I moved the photos and drawings of the Mercury engine to a separate page about the Bristol Mercury engine of the Fokker G.I.



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