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Autor Thema: Seehund Trailer Scale 1/35  (Gelesen 258 mal)

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Offline wulfing

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Seehund Trailer Scale 1/35
« am: 07 Oktober 2018, 20:27:30 »
Hi everybody,
First of all, I have never done a Work-In-Progress (WIP) before and secondly I intend to show you the build only. This WIP will deal with the Seehund trailer, since there is no commercially one available around (unlike the Biber and Molch). I take great interest in the Seehund midget submarine and the men of the Kleinkampfverbände who operated them in the last stages of the war. So, I thought I would share this with you.

Some research: I know of only 5 photos of practical use to replicate a Seehund trailer: 2x HMA, 2x IWM and 1 grainy Unknown. The HMA show the same trailer from different angles including a rear shot. Key features are the angular upper frame, the double main support I-beam, the extra wheel rim and the apparent lack of torpedo supports (?). The IWM photos show a different trailer: rounded upper frame, single support beam and close up views of submarine clamps & torpedo cradle/saddle carriages. The Unknown trailer photo looks similar to IWM, however the entire trailer is in shadow. Despite that it is a good photo to extract lengths and approximate position of the clamps.

The trailer I am building will be hybrid of both: angular upper frame and double support beams + central keel support beam and torpedo support cradles/rails + a heap of guesswork on my part. As well as reinforcements wherever necessary since the VP Seehund (made of resin) weighs as much as the real thing!

The donor kit for the trailer is Einheitsanhänger 5t by Bolddivision: wheels, leafspring suspension, axles, brakes, turntable, the drawbar and part of the frame were used (Elite Models also sells various WH trailers). The white plastics are from Plastruct, since they sell I-beams with heights of 10mm and over. For the main support beams I choose to use BSP-18: an I-beam of 14,3mm in height (500mm IRL), in retrospect BSP-16 (12,7mm = 440mm IRL) would have been better perhaps. Other items: AFS-2 angle, BFS -5, -12 I-beam, HFS -5, -6 H-beam, UFS-2 & -6 U-beam, MR-25 rod, MS-810 strip, TBFS-3 tube and VS-?? tube/pipe saddle (i do not know which one yet). In addition: 1 and 1.5mm plasti-card.


Photo 1 (2666)
The finished wheels/axle/brake. The wheel/axle interface is reinforced with 1.5mm diameter steel rod: I drilled the hub and the axle with a hand drill (see upper left).
The forward suspension assembly (upper and lower part). The upper part is reinforced with BFS-5 I-beam to match the HMA pictures. More I-beam will go on the onside of the resin frame. The spacer ring (upper left on cutting mat) should not be used. Because of that: part 6 of the Bolddivision kit (the triangular supports of the rear suspension assembly (on right side, upside down) need to be shortened by 3mm. I can recommend a fine toothed sawblade.
The grey resin frame is cut in two. Also visible is the BFS-18 I-beam.

Photo 2 (2670)
I glued two provisional cross-beams to ensure the I-beams remain at straight angles during construction; they sit at the approximate position where the foldable clamps will be on the outside. The connection plate between the I-beams and the wheel/turntable frame is made of 1,5mm card and strengthened with 1,0mm card on the inside. Note that no upper and lower flanges are added yet and reinforcement card not yet trimmed). The black Xs are a plate-extension which will sit snug (aka superglued) in the upper wheel/turntable frame (see photo 3 (2669) loose test fit).

At this point I am realising that the main support beams might be too tall (I had already accepted the fact that the upper and lower flanges of the beam are in fact too wide) and also that I should reconsider my earlier decision of omitting the slight curve in the lower part of the I-beam both front and back.

Photo 4 (2672)
A test fit of sorts: the main I-beams have been cut down to a length of 23cm; this will be not be their final length (which is 17 cm). Right now they end where eventually the trailer will end: around the same height as the leading edge of the dive planes. The pencil marks on the Seehund is where the clamps will touch the hull. This is an important benchmark to extrapolate other distances.

Photo 5 (2673)
More BFS-5 I-beams to buttress the back frame assembly. I glued a HFS-5 H-beam above were the axle is going to be. The research photos allude to some sort of construction above the axle, that stiffens the frame and to which the support beams/beam are/is connected. This is midway assembly: the I-beams will be cut flush and then using a grinding disc on rotary tool (dremel, proxxon) I slice between the I-beams to make a slit for the plates to sit snug in. The main support beams are cut to length (17cm). The connection plate is again made from 1.5mm card and braced with 1.0mm card on the inside. The angle is less steep compared to the front: a connection plate template is seen in the lower right (5mm squares). After cutting, the connection plates (all 4) need to be trimmed down a bit on the diagonal sides to accommodate the upper and lower flange.

Photo 6 (2674)
A rough mock-up, which defiantly stares me in the face: decision time. Leave the I-beam as is or put in that curve in the lower part of the I-beam on both ends. And BTW: callipers are indispensable in this project.

That's all for now.
Next up: put in that curve and start working on the crossbeams.
« Letzte Änderung: 07 Oktober 2018, 20:37:21 von wulfing »

Offline wulfing

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Re: Seehund Trailer Scale 1/35
« Antwort #1 am: 09 Oktober 2018, 11:22:38 »
Hi everybody,

Continuing with the trailer

Photo 7&8 (2679&2680)
I put in the curve: I cut/sawed out a sliver of a triangle with an opposite side of 2mm and an adjacent side of 60mm for the front and 30mm for the back (along the lower flange). Glued the flange into its new angle, gap-filled superglued the sides, tidied up the connection plates. There are still vertical plates/strips to be added where the bends start: the HMA photos show that these vertical strips fortify the I-beam and support the arms onto which the clamps are located (see photo 9 for frame overview).

I replaced the inside I-beam on the turntable frame with a UFS-6 U-beam. Between this U-beam and the H-beam on the back assembly sits the keel support beam made of UFS-12 I-beam. To make sure the rear frame was a square again I added a #6 U-beam underneath the bottom of the rear assembly to add strength and rigidity. Next came the upper and lower flanges: made of 1mm plasti-card. I am not sure I like the upper ones: constructed out of one piece of strip. It seemed like a good idea at the time; however I might end up making a cut instead of a bend. At this point it is all very rough: there is a fair amount of filling and sanding ahead.

Photo 9&10 (2685&2686)
To make the clamp support arms I cut two 60mm long pieces of HFS-5 H-beam, removed (in the middle) 10mm of upper flange and plate and glued it in place. A drop of thin superglue was added where the H-beam and the keel support I-beam connect. The location for these support arms was determined by looking at wartime photos and guestimate. In this case the forward arm sits 68mm from the front topbend in the I-beam and the rear 38mm from the rear bend (there is about 60mm between support arms). The BFS-5 I-beams in the middle will act as extra backing for the torpedo-carriage rail and an outer rim strip.
I did add the aforementioned vertical plates (12mm high, 3mm wide and 1mm thick); no photos yet.

Next up are the clamps and the torpedo carriage. That update will take longer because I have to wait for the parts to come in since I decided to make the clamps out of two U-beams instead of one H-beam.