Looking for a successor for my Koolhoven FK.43 models, the Fokker F.VII came to mind. This aircraft was first designed and built in 1923 as a larger successor to the F.II. It retained some design features of the previous model. After a small number had been built the design was altered; a more efficient wing with integrated ailerons, a simpler U/C and a longer fuselage. Later, in 1925 Tony Fokker wanted to expand his bussiness in the US and entered the Ford Reliability Tour. His US agent, Noorduijn, told him that US airlines wanted a multi engined plane for safety reasons, so the original single 400 hp Gnome-Rhone engine was exchanged for three 200 HP Wright J-4 engines. In this configuration, the F.VII 3M the type was a huge success. The - 3m was not a successor to the single engined model as multi- and single engined examples were built side by side. Each F.VII received the attachment points for the wing mounted engines. Some started with three motors but were converted to a single powerplant later in their lives. The designations a and b were introduced during the period when F.VII's were built with the b signifying the longer span wing achieved by inserting an untapered center section.
Well, that is quite enough history. I wanted a rubber powered model, so it was to be a single engined example. And I needed a decent 3-view to start with. This was found on the internet. As a bonus, an original F.VIIa survives in a museum in this country. This is construction number 5054, delivered to Denmark. This plane happily survived WW II and was bought by KLM and Fokker in 1953 and presented to the aviation museum in Schiphol aerodrome. I had the 3-view enlarged at a local copy shop, to 33 cm for possible use for a peanut model, and tot 51 cm. for an F4D model. It was then simply a matter of adding my own construction to the enlarged 3-view and the ususal mods of slightly larger tail surfaces, higher U/C for a decent size prop and a slight dihedral.
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Quote from: Stunthenk on Aug 07, 2026, 04:19 PM... a slight dihedral.
I'm struck by how like the Ryan M-1, M-2 & NYP it looks and I wonder if you might be able to do without dihedral?
Looking forward to seeing this come together.
The big difference between the Koolhoven FK.43 and the Fokker F.VII compared with the Ryan NYP is the wing, both in plan view and in section. The NYP has a parallel wing with the same section from tip to tip (I do have that correct, don't I? ) while the Dutch designs feature tapered wings in planform and in thickness towards the tips. The F.VII wing has a vertical center line with zero dihedral so it actually has an anhedral on the top surface and a dihedral on the bottom. I considered to make the top surface straight, resulting in a center line dihedral of 5 mm at the tip (I might still change my mind and do that for scale appearance) but for now I have drawn the center line to have 10 mm dihedral at the tip resulting in a dihedral on the top surface too. The Koolhoven FK.43 has a straight upper wing surface with dihedral on the center line. My larger FK.43 model flies fine in this configuration. But I changed this to some dihedral on the smaller model.
Great to see this one in the works... I have something similar in mind... so look forward to your progress
Tim
I decided to start with the fuselage - the complicated part. I first built a fuselage side from 3/32 sq. balsa, with 3/32 x 1/16 uprights. The uprights in the cabin area are diagonal and can be seen through the windows so needed to be placed carafully. I then decided that the stringers along the fuse sides were not prominent enough to put them over the uprights so I let in pieces of 1/16 x 3/32; a tedious job at best with a less than neat result. After removing the structure from the plan I decided it was too clunky and started again, this time with 1,5 x 1,5 mm basswood longerons and 1,5 x 1,5 balsa uprights. Looking closely at pictures of the real thing I thought that adding the stringers to the outside would be justified but they needed to be thin so I used 1 x 1 mm basswood for these. I also changed the structure around the cockpit a bit, trying for a better scale effect.
One problem remained, however; on my 3-view the lines of the nose were drawn as rounded, both in side- and plan view. This did not match with the pictures I had, but I could not get a clear view. So it was off to Aviodrome museum near Lelystad, nice 40 mile ride on my 1974 Moto Guzzi 750S, truly combining need with pleasure! Close inspection of the real F.VIIa showed all straight lines on the nose, with only some sheet alu streamlining on the bottom giving a rounded effect. But I found another significant item I had not seen on any plan or sketch, and had not noticed before on photographs: the fuselage sides at the cockpit area have a triangular section that cants inward! Probably to allow the pilots to look rearwards through the open side windows. At the museum there is also an exhibit of a crashed F.VIII that was retrieved from a desert sometime, and the rusted bare steel tubing displayed the same feature. So back home the fuselage sides were modified once more and could finally be built into a basic structure.IMG_5865.JPGIMG_4731.JPGIMG_5866.JPGIMG_5901.JPG
Here are the final pictures belonging to my previous post.IMG_5904.JPGIMG_5907.JPGIMG_5909.JPG
For stringers like those, which barely show through the covering, I use fine carbon rod. And you you won't accidentally squeeze and break them.
That sounds like a good idea. However, since I have none in stock, I'll have to stay with the basswood. But it makes me think that for a Peanut, you could use thread.
The next step for the F.VII fuselage was to add the U/C. I bent the main leg (the rear one) from 0,8 mm pianowire (21 gauge) and the supporting leg from 0,5. (25 gauge). The wire was bound to the crossmembers with fine silk thread and glued with medium CA; the ends were bound with fine copper wire and soldered.
The instrument panel will be hardly visible so I 'suggested' one with brown tissue on a former with the instruments indicated with a black marker using a circle template.
The nose sheeting was first made to size using a paper blank and was then cut from soft 1 mm balsa. The sheeting felt too coarse so I sanded about half the thickness off. When glueing sheeting I prefer to glue one side in place before doing the rest. Unfortunately I damaged the sheeting in a clumsy movement so I had te make a new one. I decided to cover this on the inside with lightweight tissue for strength; that has the added advantage that it already curls. There are open windows at the rear of the cockpit; I glued lengths of thread in place to make cutting them out easier.
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Fokker FV11 peanut Aug 12 2026
Very nice build and pics Stunthenk! 8) You are inspiring me to get back at my stalled 30 inch Gipsy Moth ...
Lastwoodsman
Richard
Always follow any inspiration to pull a stalled project free! If I am to be an inspiration; we are having another heatwave in North-Western Europe but I am fortunate in having a modelling room on the ground floor - first floor for those on the other side of the Atlantic. So in stead of going out and doing usefull things I cut a set of ribs for the F.VII wing from 1 mm balsa. As I only had the section of the center rib, I 'extrapolated' the section of the other ribs. I simply took the length of each rib from the top view of the plan and the thickness from the front view, and used the front part of the plywood template of the Bill Werwage Juno plan that I cut in 1983 for the curved part. (For those who lost me here; the Werwage designs of control line aerobatics models used the so-called Detroiter construction for the wings using rib strips in stead of full ribs for lightness. A typical wing strip was 3mm balsa 6 mm high or 1,5 mm 10 mm high. It turns out that the curves or sections of those wings are very similar to the wing sections we use). The noses of the wing ribs were drawn with the use of a Burmeister set of drawing curves. As each smaller wing rib was fashioned, is was eyeballed to check if it conformed to the next larger rib and copied for a 2nd example. After all ribs had been cut, the 1,5 x 1,5 slots for the spars were cut with a small file. Next the rib noses were cut down to allow for the nose sheeting, and slots were cut for the 2,5 x 2,5 mm leading edges. Then it was a small job to cut the TE, LE and spars from sheet and assembling the wing on the plan.
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Nice careful work there Stunthenk.
A approach I have found helpful for building rectangular or straight tapered wing such as the wing you are building, is to build the wing with root and tip aerofoils shaped with blanks in the other rib positions.
Once the wing rib blanks are glued in place, the blanks are shaped with a straightedge using the root and tip ribs as templates.
The root and tip airfoils are protected with masking tape which is also used to hold the wing down.
I add the spar slots using hacksaw blades with a straightedge guide, after shaping the ribs. The hacksaw blades are pulled backwards with light pressure. Notch sanders would also work well.
John
Beautiful work and model Henk!
Cheers, Ramses
Your approach sounds very well thought out, but with this Fokker wing the wing section decreases in thickness so strongly, that I thought my approach would be the only way to achieve success. With with less accute decrease in thickness and taper I have used the technique you explain myself. Another problem is the slots for the spar. As my thinnest file is 1,5 mm thick, I find it difficult to make consistent sized slots smaller than that.
Well, back to this build. After some thought I decided to lift the wingtips (at rib 6) 10 mm. This would leave the top of the wing horizontal but still show some dihedral. Perhaps a little more difficult from the aspect of stability, but better for scale appearance, I thought.
So the tips were lifted, center section spars were added, and spars and trailing edges glued together. In this form the wing was stable enough for some sanding. The TE was sanded down, and I sighted along the ribs at the LE. The hand made rib shapes were well aligned, only some detail sanding was needed to achieve a uniform section throughout the wing. A rib standing out must be sanded down, to misquote a Japanese proverd. The slots for the LE needed some more work, but after that the LE fitted nicely and was sanded down to conform to the section.
The next step was bending the tips out of thin bamboo over a soldering iron, and pinning down the wing half to fit and glue the tip. After sanding this to shape and fitting the right hand tip, some LE sheeting was sanded down from soft 1 mm sheeting to approx. half thickness. The sheeting was applied in three sections: center and both wing panels. The sheeting was first glued to the spar, and then to the LE. The center section was also sheeted on the bottom because a cut-out for the cockpit must be placed under the wing.
After a final detail sanding the wing was put on the scale; 5 grams, not unreasonable.....
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The next item on the build list were the tail surfaces (anything to avoid the dreaded engine!) The stabiliser was built entirely conventionally, 2 mm thick with 2 x 3 mm LE's, 1,5 x 3 TE's en 1x5 x 1 mm ribs. The fin was built around a hot bent bamboo outline. Bending an outline this strongly curved turned out not to be too easy; it is essential to keep moving the bamboo as you bend it over the shaft of the soldering iron. If you hesitate is all too easy to get a crack or even a break. And all this as you are holding your fingers a few mm. from the iron! Anyway, the second attempt suceeded. The bamboo was from an old chopstick. For both the stabiliser and the fin I added a provision to separate the rudder an elevator.
With the tail surfaces built and sanded it was time to see if it was starting to look like an F.VII!
Nice work , very neat.
What is a thickness of the LE sheeting?
Marcin
About 0,6 mm. I started with a 1 mm sheet that weighed 9 grams (standard size, 1 meter by 10 cm. so a density of 0,9). After applying the sheeting I did some more carefull sanding at the spar and the LE so now it is anybody's guess!
Nice work Stunthenk! Your use of bamboo is interesting.
John
With a model like the F.VII construction goes along fine, untill you get to the dreaded exposed engine. Then all momentum disappears.... That's the reason why this update took a while. First you have to design your model engine. In this case the engine is a Bristol Jupiter VIIIF, a 9 cylinder single row radial engine with a front exhaust collector / silencer. According to my enlarged 3-view the diameter should be approx. 36 mm. I therefore decided the diameter of the crankcase to be 18 mm, leaving 9 mm for each cylinder assembly. Perhaps scalewise the crankcase should be smaller. But in the model it is also the noseblock so it needs to be sufficiently sized. The cylinders have a part with slightly larger cooling fins under the head. The cylinder head has exposed rocker arms and valves. Each cylinder has two exhaust ports, with a Y shaped pipe connecting to the exhaust collector. The collector has two exhaust pipes going to the rear of the motor.
In the first picture you see the noseblock / crankcase in he model, a test cylinder and 9 cylinder stubs on a stick board between two supporting sticks to be sanded down to the correct size. Nine thinner, larger diameter stubs are wainting their turn on the sticky board to be sanded; and 9 3 mm balsa oblongs are waiting to be turned into cylinder heads.
In the second picture you see 9 cylinders under construction, the exhaust collector and the test cylinder.IMG_5996.JPGIMG_5998.JPG
Great to see this amount of detail. Good luck with the rest.
Quote from: Stunthenk on Sep 01, 2026, 04:46 PMWith a model like the F.VII construction goes along fine, untill you get to the dreaded exposed engine. Then all momentum disappears....
Aye. You have my heartfelt sympathy. :)
However, I'm in complete agreement with Dave; the level of detail is very impressive.
Thank you very much, kind gentlemen, but in my opinion this is simple balsa bashing and not comparable to the efforts of the real experts. Just look at pictures from Walsall and Wychen models and you know what I mean! And I still try to figure out how to do the Y shaped exhaust pipes? (And of course, I HAD to do an airplane flown BEFORE the introduction of NACA style cowlings....) IMG_4731.JPG
Quote from: Stunthenk on Sep 01, 2026, 11:53 PM...still try to figure out how to do the Y shaped exhaust pipes?
Henk, if the exhaust stubs aren't too small to work with might something like the sketch below work? Make the Y joint in basswood/bamboo and then paper tube extensions into the Townend ring and the cylinders.
I've tried to make satisfactory cylinders with cylinderheads but I am simply not satisfied with the results. I will have to start over. But, in order not to stall the project, I've decided to postpone that. But that brings me straight into the next problem, the burnished metal aereas on the nose! Of course I've read with interest Lurk's experiments with fake silver leaf; and I suggested using Bare Metal foil. Well, that was my starting point. I punched out 2 mm disks of 600 grit wet & dry paper and stuck that to a round balsa stick. No joy, the result was irregular scratches. So I stuck another disc to a piece of 2 mm dia, wire with a rounded point; not much better. Finally I remembered reading somewhere a long time ago that the eraser on the back of a pencil would work. And indeed, neat round burnishes. But 8 mm dia, much too big! Next step was a 2 mm slice of eraser held in a pin vice. Not bad! But when I cut the piece of foil from the backing and smoothed it on a piece of soft balsa, the marks became too indistinct. The Bare Metal foil was too soft! And trying to burnish the foil while on the balsa resulted in dents. Lurk's Ryan NYP report featured a finished model by Peter Smart where the burnishes were made with a silver marker pen on painted tissue. I took a 2 mm Molotow silver marker and applied that to the foil. Reasonable, but the Chrome ink looked darker than the foil; I had expected the oposite. Oh, well, exit the Bare Metal foil.
Next step was silver tissue. Mine is no modelling tissue, but came from a stationary store. It tears very easily along the grain so is useless for covering open areas, but the nose of the F.VII is sheeted. This tissue has a dull and a shiney side, and the Molotow dots on the dull side look promising. So that is what I am going to try.
But first I need to cover the fuselage. The structure visible through the side windows was painted red brown to match the F.VII in the Lelystad museum, rectangular window strips were cut from thin transparent plastic and applied using thinned UHU Hart. Then the aluminium strips separating the individual windows were drawn with a 1 mm Molotow chrome marker. The hard part was cutting the side pieces from blue and black tissue. The top and bottom of the fuselage were covered with blue tissue using Deluxe tissue paste. In the picture the top and bottom tissue is awaiting trimming after which the side piece can be applied.
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Surfing on the internet for more F.VIIa pictures, I found a true treasure trove of pictures of early Dutch registered airplanes, on a website called Nederlandse Luchtvaart (Dutch Aviation)
https://www.nederlandseluchtvaart.nl/forums/showthread.php?34754-Foto-s-van-vooroorlogse-H-PH-PK-en-PJ-toestellen-die-ook-nog-thuis-lagen
Very worth the time to browse! They had some more pictures of the plane I want to model, the H-NACT as it was delivered to the museum at Schiphol in 1955. These pictures clearly show that this machine had closed side windows at the cockpit, and the engine exhaust collector ring was coloured burnt iron in stead of the virginal shiny metal on the motor in the current museum.
But I also found the second photo! This is PH-ADZ, assembled by KLM from parts of two damaged machines, and equipped with a P&W Wasp with Townend ring! Much easier to make!
In the mean time, construction of the model proceeds.img476.jpgFoto 143. PH-ADZ (ex H-NADJ, H-NADZ). Fokker F.VIIa, kopie.jpgIMG_6018.JPG
1955?
Indeed, see: https://www.oy-reg.dk/register/1897.html But the pictures of the arrival by air at Schiphol must be in 1956, after Fokker had refurbished and repaired it.
For more on this plane, serial number 5054, see: https://www.fokker-history.com/f-viia
Great build report on a special airplane.
If you're ever passing through Switzerland, the Swiss Museum of Transport in Lucerne is worth a visit. A Fokker from the former Swissair, featuring a cowling-covered engine, is on display there.
I'll be following the report with interest.
Peter
Yes, I know, that is serial number 5005. Also a very important survivor. If I were Swiss, I would finish my model in these colours!
I always had 'a thing' about FVIIa H-NACT*- decades before I started aeromodelling. So all the best with your project.
Stephen.
*Why did I have 'a thing'? . . .No idea. Too long ago.
Post Script:
https://www.youtube.com/watch?v=vX8LTWSBq7o
Indeed 1956. After the plane had been delivered from Denmark, it was refurbished and repainted by Fokker.
The first picture shows how it looked when it was ferried, the second picture as it came out of the Fokker paintshop.
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While surfing the net in search of more info on the F.VIIa I found a building report by a Dutch modeller who scratch built a static (non flying) model. It featured very nice burnishing on the nose panels. The builder explained that he used aluminium tape, and made the marks with a small brass wire brush in an electric drill. So I went to a hardware store and bought a 5 cc. wide roll of aluminum tape. 10 meters long, if it works I can build the entire pre-war Fokker fleet. But the smallest cup shaped wire brush I know still has a diameter of 8 mm., so I dug up the small length of 2 mm pianowire with a 2 mm disc of 600 grit sandpaper glued to an end that I made earlier. I clamped that in my Dremel, and well, well! simply briefly touching the tape with the spinning bit produced nice marks! I made a test piece, cut the tape to size for a side panel, removed the backing and the tape allowed itself to be smoothed to the balsa witout losing the marks and without any wrinkles. Of course, the metal panels on the F.VII nose are flat or have a simple curvature. For a double curvature I don't know if you could apply the tape without wrinkles. And applying the marks is mind numbing work....
Still, the aluminium coloured tissue will be removed from the nose, and burnished tape will be applied as the last step before assembling the model.
First picture: the static model; second picture: the burnished tape test piece.
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The ali tape is mallible enough to conform to a double curved surface if burnished down with a plastic spatular. This requires a smooth, hard surface or you will crush grooves into the surface. It is best to experiment on a trial part first.
I would cover the nose in tissue and seal it well. You can afford the increase mass on the nose. Any texture, such as unfilled grain may be picked up by the tape if it is not smooth