Thulin Type D

[Torbjorn]

Modelling time! But first some babbling.

 

A few days after he defended his dissertation «On air resistance on flat surfaces», Dr. Enoch Thulin travelled to France and enrolled at Bleriot’s flying school for more practical aeronautical exploits. He passed his tests in October 1912 and received the tenth license in Sweden.

He was one of six children who had lost their father early and performed his studies on stipends. Through his studies he became a member of the Swedish aeronautical society, which housed a number of distinguished members of society bitten by the flying bug. There, he got in contact with several wealthy individuals who became both friends and benefactors, including Tord Ångström, grandson of the physicist, Nobel laurate Gustaf Dalén and Gustav Ericsson, son of the founder of the Ericsson telecom business. With their backing, Thulin would build up one of the first independent aeronautical companies in Sweden.

 

After returning to Sweden, Thulin bought a well-used and worn Bleriot XI. He found a partnership in airplane mechanics/producers Nyrop&Ask, who contributed with the necessary practical knowledge,which became the foundation of his company. They started license-producing Bleriot XI under the name Thulin A and later opened a flight school. This was in 1914. Thulin quickly bought the shares from his partners. 

 

Before the war broke Thulin acquired a Morane-Saulnier Type G and license rights to their aircraft: The MS G became the Thulin B and MS L the Thulin D. He reverse-engineered a Le Rhone 80hp engine which went into mass production as the Thulin A  (yes, he named the engines the same way as the planes - there was also a car Thulin A). Starting with the Thulin E they started producing their own designs, and found a market in the non-warring nations which otherwise had troubles acquiring both aircraft and engines and the company grew to almost a thousand employees. 

 

Both Thulin and his company met an abrupt end. The war ended, filling the market with cheap surplus material, and Thulin himself crashed fatally during a practice flight in May 1919. 

 

I have long contemplated builing models of the different Thulin types, and this is a good opportunity. I am intending to build a model of a Thulin D - a license-built Morane Saulnier L, the parasol scout. Thulin tinkered with the design, and it differs somewhat from the original. The dimensions are different, and the engine was a Thulin A, and the front end was rebuilt to a more aerodynamic shape with a smooth fairing flush with the cowling.

The wing appears to sit lower as well, giving the Thulin D a more compact look. 

 

Very few of this type were built: two were bought and donated to the army by a women’s organisation and three more used by Thulin’s own flying school. The type still made a mark in an unexpected way: one of them ended up as the first aircraft of the Finnish air force, resulting in the Finns adopting the swastika: it was the donor’s personal emblem with which he had emblazoned his plane.

 

Wiki has a free photo:

 

 

 

Blabber finished, back to modelling. The centre-piece will be a Smallstuffmodels engine:

 

The rest will be put together from sticks and strings and hopefully the occasional PE left-over.

[trickyrich]

welcome along......with an interesting build... and only the engine to start with!!! 

 

Most members start with a model and in a lot of cases build an engine for but you've gone the opposite!   

 

More real modelling, great to see! 

 

Good luck with this one, I know there'll be a lot of interest in this build for sure!

[Marlin]

WOW

What a project Torbjörn.

I'll for sure follow your progress on this one. 

God luck with your build. 

/Bosse

[Torbjorn]

Thanks, gents!  I have made a start.

 

The first step was to modify drawings: I only found MS L drawings, and although the wing appears almost identical, the Thulin fuselage is shorter and the height lower. The latter is explained by a lower wing. I modified the drawings somewhat to account for the shorter length mostly by reducing then aft section. 

The largest difference is in the front. While the MS has a square cross section all the way to the engine mount, Thulin streamlined his plane by adding plywood panels gradually curving to attain the curvature of the cowling. The back side was straight. The panels were mounted on extra, curved support frames. I will try to plunge mold these: the inner sides can be seen, and the support frames are thin and week, so the panels will have to hold their shape without forcing.
 

With no drawings, I decided to use the engine to measure the cowl diameter. Thus the first step was to attach the cylinders:

 

 

 

I added some spark plugs that fell off from the sprue when I cut loose the cylinder. With this as a guide I cut a fire wall for the engine.

 

 

After that I cut the bottom and flat side sections of the fuselage. The sides are cut too large and will be cut/sanded down to shape, which will be defined by the upper and lower covers sitting on solid bulkheads. In the visible front section I built up the frames (the curved frames holding the front side panels will just be shaped and glued to the currently missing panels), which will be guided into holes in the engine plate.

 

 

 

I have no info on the cockpit details and will base it entirely on the MS L. The cubic box which will hold the front seat doesn’t exist on the real thing: I added it for support and it won’t be seen.

[JeroenS]

That's some quick work and a good start!

[Torbjorn]

3 minutes ago, JeroenS said:

That's some quick work and a good start!

The research and drawings were prepared in advance 😛 I’ve been waiting for ths GB!

[Torbjorn]

 

 

I haven’t put a driver in a model since I was a kid, but this Airfix Spitfire pilot is invaluable as a sanity check.

[Bertie McBoatface]

You make the process sound a lot easier than (I suspect) it actually is. 

[trickyrich]

great start, assembling that motor would have driven me crazy, those parts are so small!

 

It will be interesting to see the transition of the fuselage shape....... this will be awesome

[Torbjorn]

The engine does have small parts, but that’s the fun 😛 

 

On 9/9/2021 at 5:21 PM, Bertie Psmith said:

You make the process sound a lot easier than (I suspect) it actually is. 

 

Not so difficult yet - patience and care does 90% of the job.

 

Some paint on the interior parts. Frame bracing wires have been attached, to be stretched when the frames have been fastened on the fuselage pieces as they would otherwise be distorted.

 

 

 

[trickyrich]

gee that looks amazing! 

 

The controls and and stressed wire, hard to believe this is a wee 1/72nd beastie. 

 

I love following your builds

[John Masters]

Wonderful!

[Old Man]

Excellent work, Sir!

 

Glad I took a look, this a great project.

[Torbjorn]

On 9/13/2021 at 9:36 AM, trickyrich said:

gee that looks amazing! 

 

The controls and and stressed wire, hard to believe this is a wee 1/72nd beastie. 

 

I love following your builds

 

The driver’s compartment does a bit of time with all the wee details. It’s finally done: leftover PE intsruments and throttle, a faux fuel tank from aluminium can, remaining wires, chair from styrene etc.

 

I also had to remove and move the stick forward a whole mm: the stick goes through the underside and the wires go beneath the fuselage for a bit before entering inside again, in the middle of the observer’s cockpit (those wires are visible in the first photo). This I hadn’t noticed until checking the drawings - after I had installed it erroneously.

 

 

 

Enough with this. Lacking a lathe, I ordered some suitable dowels to make moulds for the cowling and panels. If I had planned better I should have ordered it earlier, since the will likely take a couple of weeks to arrive. At least it leavs me plenty of time to attend to other things: next up flying surfaces.

Edited September 18, 2021 by Torbjorn

[trickyrich]

WOW!! 

 

You didn't swap you build out for a Wingnut Wings model did you? 

 

The detail work and scratch building work is amazing, more so when you know it's all in 1/72nd! Those wires you are using are just so fine....my poor eyes couldn't handle them.

[Torbjorn]

On 9/19/2021 at 1:17 AM, trickyrich said:

WOW!! 

 

You didn't swap you build out for a Wingnut Wings model did you? 

 

The detail work and scratch building work is amazing, more so when you know it's all in 1/72nd! Those wires you are using are just so fine....my poor eyes couldn't handle them.

 

I wish - I never got this far on a WNW kit. Best I can offer is a comparison with a half-finished WNW engine from a Ninak. 😛

 

 

(I do have optivisors for wire work)

Edited September 21, 2021 by Torbjorn

[Torbjorn]

 

Flying surfaces.

 

 

Tailplane and rudder
The tailplane on the MS L/Thulin D is held by an axle which in turn is suspended by brackets extending behind the fuselage. I simulated the brackets by short pieces of brass tube (holding an axle made of .3mm brass rod) glued directly to the fuselage. To make a strong enough bond I first prepared the aft edge of the fuselage to have a round indent for maximum contact surface. This was made by heating a needle of the same diameter as the tube and pressing it into the edge:

 

 

Control horns should also sit the same axle - I was lucky and found perfect double-sided horns with a .3 mm hole in the middle, on a PE sheet named ”WWI accessories” or somesuch.

 

The tailplanes were cut and sanded from sheet styrene. There is a longitudinal ridge where the axle goes through. Although my axle only goes a mm inside I hinted the shape by glueing strip along the line and sanding down - the strip’s purpose mostly to ensure a somewhat straight ridge. The rudder was cut roughly, still a work in process:

 

 

There are no stationary stabilisators: the entire tailplanes are elevators (they are turned wrong way on the photo above) and the fin a rudder.

 

 

Wing

 

The wing was made with a twisted version of the usual method of embossing ribs on a thin plastic sheet and wrapping around an inner core.

 

First the spar and rib structure was transferred from drawings to the plastic.  Then the ribs were embossed with an old pen:

 

 

Instead of sanding and bending a whole wing to wrap this so called skin around, I added the leading edge (metal tube for strength and rigidity) and spars of suitably thick styrene strips. A few ribs were added too. It looks a bit wavy here but gets straight and rigid when the lid is closed, so to speak.

 

 

After closing and glueing, the edges are reinforced with a bit of CA and sanded to shape. There are two reasons for this method. One, it is much easier to get a proper and above all consistent cross-section than filing a thick slab of plastic. Secondly it is quicker. Ok, three reasons. The third and main is that you get a translucent wing: 

 

 

 

Hmm, the wing on the right looks a bit warped but that’s ok since the machine was controlled by wing warping in any case. The shadow is from a piece of tape.

The translucency means I don’t have to paint (which I don’t enjoy) to get this effect:

 

 

Still haven’t made up my mind about which specific aeroplane to make (Finnish, Swedish army or Swedish civil in Thulin’s school).

Edited September 21, 2021 by Torbjorn

[Mjoo]

20 hours ago, Torbjorn said:

Still haven’t made up my mind about which specific aeroplane to make (Finnish, Swedish army or Swedish civil in Thulin’s school).

Finnish, pretty please?

[trickyrich]

gosh that wing looks amazing!!!

 

You made the whole process look so simple, but I know it's not quite that!  You can add a 4th reason for the super glue too I think, extra strength for the join. I've used it before for on some super thin joins, give you extra strength without the worry of plastic glue melting the plastic too much.

 

The transparency of the wing is perfect, what about the colour? Do you need to paint it? Some really light coats of super thinned paint would do the job without losing the transparency of the plastic too much.

[Torbjorn]

On 9/22/2021 at 5:00 PM, Mjoo said:

Finnish, pretty please?

It is definitely the most important role of the plane, which speaks for - but I’ve seen plenty models of it, whereas none of a Swedish. Still haven’t decided.

 

22 hours ago, trickyrich said:

gosh that wing looks amazing!!!

 

You made the whole process look so simple, but I know it's not quite that!  You can add a 4th reason for the super glue too I think, extra strength for the join. I've used it before for on some super thin joins, give you extra strength without the worry of plastic glue melting the plastic too much.

 

The transparency of the wing is perfect, what about the colour? Do you need to paint it? Some really light coats of super thinned paint would do the job without losing the transparency of the plastic too much.

 

Yes, it adds rigidity too, not just strength. And Tamiya liquid glue smelting the plastic is indeed a large nuisance. I’ve ruined one wing that, and  defiled the ether with lots of naughty words. 

 

I will need to paint it, but the translucency remains if you airbrush a light colour with thin layers. CDL in this case. I did it once before, I will aim for something similar now, but just a tad thicker paint layer:

 

 

 

[Torbjorn]

One small update: the ”mast” on top of the wing to hold the rigging. The six forward wires (3 on each side) are to be fastened to the eyelets on the mast, the 3 aft ones go to both sides, passing through a pulley. The mast itself is flattened brass tube, the eyelets thin wire spun around a .3mm drillbit to create the eyes. Those and the wire holding the pulley was soldered together. One or two of the eyes will need to be spun a few more turns and some other corrections (like covering the spiralled wire with something to make it look solid), but I’ll do that when rigging it.

 

The pulley is a piece of plastic rod, superglued after the rest had been done. 

 

 

 

I still have some sanding to do to smooth the edges around the cut-out in the wing, but after that I can’t do much until the dowels arrive.

Edited September 26, 2021 by Torbjorn

[Paramedic]

Really impressive work.

[arfa1983]

Absolutely fantastic. That see through effect is unbelievable 

[Col.]

Fairly sure the word 'wow' has been used already in this thread but it bears repeating; stunning work

[Torbjorn]

Thanks for the compliments guy, it’s encouraging!

 

Searching how to mold cowls gave plenty of results of people calling it easy or a piece of cake. I have to disagree, this was darn difficult. Turned out the dowels I ordered were all too small, but a Roden Camel cowl turned out to be perfect. Doh. Still, it took quite a few attempts before I got something remotely acceptable. Note to self:

1. use quite thick plastic and allow a lot of extra space - it will be too thin at the back edges otherwise

2. make the female mould quite tight and smoothen the edges. I haven’t molded anything with a high aspect ratio previously, and serrated edges haven’t been a problem - here it made ugly marks and ruined several cowls

OR

3. Forget molding and buy a cheap old  kit with a suitable cowl!

The leftovers after some but not all more or less unsuccesful tries:

 

The chosen cowl was then whittled down to somewhat correct shape. Honouring the local traditions («rulers, compasses, levels, markers etc are for people who don’t know how to do things») this was done by eye. Getting closer:

 

 

In case anyone wondered, the strings are wires handling wing warping.

Edited October 1, 2021 by Torbjorn