Now pics of the trombone on the trailer in both conditions: folded and ready to rumble (both without the final camouflage until now).
First the unfinished folded version to show the cone inside:
and
And the other version:
and
(as I'd said: 4 to 4 meters in a square)
The hydraulic jacks are made by toothpicks. Putting the toothpicks into a Dremel's collet and sliding with a fingernail-file over it's surface, I'd made the typical view of hydraulic columns.
Both versions have it's own hydraulics to change them as the trailer's load and use it as the fixation on the trailer and its holders, and to show the different views of the heights of both conditions.
On the trailer's left side of the platform you see the electric pump with the cover of the electric engine and the pressure tube/barrel of the hydraulic oil pump.
There won't be a lot of oil needed, because the hydraulic columns having walls massive enough to fullfill it's 2nd task: stabilising the speaker on the trailer during the transport.
Because the highspeed of the Stug III in armed version only was 30 kms/h it maybe will have a Vmax of 20, maybe 25 kms/h with both trailers, the electric powerplant trailer and the trombone trailer: so there won't be strong forces to the structure.
(Don't worry: if the trombone-train will be transported by the Reichsbahn, the speaker will be secured additionally on the trailer and on the car! There were specific instructions for.
)
Norbert