RPG-40 + RPG-41 Grenade

A full scale replica of the iconic World War 2 era Soviet RPG-40 (handheld anti-tank grenade, model 1940), made for demonstration and throwing. It carried a 760g payload of TNT, which was enough to overcome tank armour early in the war. When the German tanks eventually grew thicker skin, it’s production was phased out beginning in 1943 to be replaced with the shaped charges RPG-43 and RPG-6. Despite this, it remained in use throughout the war.

A less common variant with about twice the payload, the RPG-41, was also in service from 1941. It's often illustrated with a strangely ridged spoon, but all documented examples I were able to find contradict this. If you have any evidence that it really existed, feel free to correct me and I'll model it!

The grenade had a surprisingly complex design. The spoon/lever was held in place by the safety strap and tension from the protruding bottom hook holding the long sprint which lied flush against the handle. When released, the spoon pulled both the short and the long sprint out in flight, releasing the internal mechanism. After this the grenade would detonate on impact.

Models are mostly based on measurements of relics found available online. Walls are slightly thickened to give it more rigidity and the thread is both wider and deeper to give it more strength. The internals are only enough to be able to simulate the basic external functionality. Grenade body is hollow to save material and to allow fitting of ballast to obtain a proper weight.

For the fabric strap, use either webbing or a strip of canvas. The provided plastic strap edge is meant to be glued and folded around the fabric edge, though is not a required part. A small bit of metal wire is needed to secure the strap and a small nail is needed to fasten the fuse latch. If possible, bend a piece of thicker metal wire to replace the sprint and hook, or even an extension spring for the later part.

For better bed adhesion, use a brim when printing the spoon. The loop on the handle require a small support structure. Use a variable layer height for the body to get good detail at the bottom without the print taking forever. The tiny parts as usual benefit from a fine layer height.

Designed for a 0.4mm nozzle (though body could be printed with a larger one)