Test a

[franzkait]

What is this ?

[jumpinjan]

Tool to check gun synchronization to prop.

[Machinbird]

Probably some sort of aerodynamic test rig to gather pressure data in the flow field surrounding the propeller. The tape gives it away as a temporary setup. The vertical arm probably goes over the top of the prop to the top wing center section.

[jumpinjan]

Machinebird, it has hydraulic lines in it and attached to a cylinder looking shape. Could it be a prop hub puller?

[franzkait]

maybe this helps

[Machinbird]

Franzkait, Don't tell me it is a mechanism to jettison the prop inflight in order to get glide information undisturbed by the propeller airflow? I was wondering why all the lines ended at the hub.

[jumpinjan]

I'll return back to my original hypothesis that its to measure gun synchronization to the propeller using hydraulics. I don't think this was at the depot level, but probably a factory experiment.

[franzkait]

why shut anybody take the synchronization from the front,if the same possibility exist at the back ?

[Machinbird]

Another possibility would be an in flight propeller balancing system test rig. The eccentric nature of some of the items on the prop shaft would permit altering balance to a substantial degree. The central cylindrical item is obviously a slip joint to pass pneumatic/hydraulic connections from the vertical arm to the rotating propeller hub. I don't see anything resembling an actuator however.

[van der Laan]

I figured it out!

It is a BEER TAP, flown only during Oktoberfest!
Flieger simply holds his STIEN above the wing and it is instantly refilled.