1:35 mideget submarine "Hecht" (Micro Mir) - display model

[DrSchmidt]

Continued with the drive train. The rpm of the electric motor was reduced by a dual belt drive that then coupled to the propeller axis. According to the drawings, the thrust bearing was simply attached to steel girder that was welded into the pressure hull. Simple enough. Left and right of the propeller axis were pressure bottles (air and oxygen). I chose to paint my depicted port one green for oxygen (no reference photos telling otherwise, so I can opt for more color). I also installed the steering column with its mechanics for the cable pulls for rudder and trim weights. Flimsy, but I got it in place without damage. On the port ballast tank a shelf with alkaline canisters found its place, and on the front side of the gyro compass cowling one can see a Papenberg depth gauge.

[DrSchmidt]

Continued with the interior of the crew compartment. The base color (flat white) was applied and weathered using gray filters and washes. Then the gyro compass and its housing were painted, weathered and glued into place as were the respective switch boxes and the motor converter. Starts to get crammed in there....





The battery nose was also airbrusched and weathered and then the batteries glued in place. The batteries are flat black. To make them look like somethimng I applied a weathering with gray filters and then I gave them some conturs using dry brushing.

[DrSchmidt]

After building a shelf and starting the build for a display box for the Discovery I found again some time to work on the Hecht. Started with the battery section. It contains two floors, some kind of grating construction, that hold two torpedo batteries in the middle and one on the top. The third battery sits directly downstairs on the keel. Left and right of the bottom battery are the movable trim weights. The sit on thread rods taht are actuated via chain drives by the front driver of the boat. Another chain drive on the front bulkhead was used for mine release and was actuated by the front driver as well. Left and right of the top batter are two compressed air bottles. Tight fit and especially the chain drives were quite challenging, as they are very, very small.















Here's an overview of the current status with the nose battery section that was used in the torpedo version.

[DrSchmidt]

Wile doing the monotonous jobs on my Discovery, I converted the CAD model into a printable version and added the additional battery nose that could be used when the boat carried a torpedo instead of a mine. As the boat is going to be cut away, I had to remove some equipment of the starboard side to allow for an unobstructed view into the interior.



Then I started by printing the frames, keel and battery bulkhead for the port side as one piece that acts as inlay for the kit's hull. Tiny and really hard to handle, but in the end, the result looks quite O.K.

[DrSchmidt]

Added some more bits in pieces. The model contained all major parts when I left it, but for actually make it printable, there is still much fine tuning to do...

[DrSchmidt]

The guy in the front controlled the throttle (cylindrical canister on the right), released the mine (or fired the torpedo) and actuated the trim weights left and right of the batteries (to correct general trim when the mine was detached). I guess he also operated the ballast tanks.

I think the Hecht midget submarines and the midget submarines in general were a reaction to the successes of X-Crafts against the Tirpitz (Operation Source), which also used mines. That lead to the founding of the "Kleinkampfverbände" (small arms units) which the midget subs were a part of.

I agree, the first generation of midget submarine (Hecht, Molch, Bieber, Neger) were not really usable and came close to the Japanese suicide subs in terms of fatalities of the drivers. One has to imagine the time: late in the war, resources and time became scarce. Desperate tries. And then stupid requirements form the naval command, like e.g. the gyro compass.

[He Who Shall Not Be Named]

That thing was a complete disaster....did you notice the cylindrical things left & right of the aft seat? Movable weights that acted as pitch control....as there were no actuated dive planes. Worked like **** and later they installed dive planes. Didn't make anything better. The nose was a detachable mine. Basically you screwed it loose with a hand crank. When the mine was detached the boat hat an almost flat nose. How immensely clever....all in all the boat was not usable and the few that were built acted as school boats. I guess the idea was, that f you'd be able to steer that thing, you'd be great anīt anything better.

I can imagine trying to shift weights mechanically to anticipate and attenuate the boats pitching -- you'd never get on top of that curve! And what was the function of the non-driver? CO2 absorbent can swapper and moral support?

But to be fair, halting steps like this design did eventually evolve into Seehund. German's are first-class mechanics and Engineers... with the occasional mean-streak breaking out every half-century or so.

[DrSchmidt]

That thing was a complete disaster....did you notice the cylindrical things left & right of the aft seat? Movable weights that acted as pitch control....as there were no actuated dive planes. Worked like **** and later they installed dive planes. Didn't make anything better. The nose was a detachable mine. Basically you screwed it loose with a hand crank. When the mine was detached the boat hat an almost flat nose. How immensely clever....all in all the boat was not usable and the few that were built acted as school boats. I guess the idea was, that f you'd be able to steer that thing, you'd be great anīt anything better.

[He Who Shall Not Be Named]

My God! the size of the MG set and gyro-compass! Well... you gotta work with what ya got!

[DrSchmidt]

Continued to detail the CAD files to actually fit the model. The hull thickness of the kit of course is not to scale. So I hade to scale down the CAD model in two dimensions a bit to fit the kit. Now some detail work to make everything into a printable interior....

[DrSchmidt]

Again a little update: The bow trim weights and the sea mine were manipulated by hand wheels by the engineer (front seat). The hand wheels acted via bevel gears on axis that turned the chain drives of the trim weights and the sea mine. All that is in place. Some holding brackets, the periscope and the hand drive of the bow hook still need to be added. Soon...

[DrSchmidt]

The big parts are done....last bit was the cooling equipment for the gyro compass on starboard....

[DrSchmidt]

Further progress....the electric motor was coupled to the prop shaft via a two-stage belt gear reduction. That and the thrust bearing block are in place. Left and right to the prop shaft are a compressed air and an oxygen bottle respectively.

[DrSchmidt]

Little update.....more alkaline cartridges and detailed racks. Started sketching the speed controller (cylindrical shape with hand wheel) on the starboard side of the front seat (engineer)...

[DrSchmidt]

The compass repeater on port and the depth gauge on starboard are in. On top of the negative tanks are alkaline cartridges for the air renewal. Getting more and more crammed....