Here is the blurb on the Speed 600 Eco from the Westbourne Models web site -
Graupner Speed 600 Eco Pt No 3323 Ref: 2100
One of the best of the series for General Scale Model Boating
Low-cost, current-saving versatile Speed Eco motor for a wide spectrum of applications.
Specs:Nominal voltage 7,2 V Operating voltage range 6 ... 9,6 V No-load rpm 11000 minNo-load current drain 1 A Current drain at max. efficiency 7,5 A
Current drain when stalled 50 A
Length of case, excl. shaft 57 mm Diameter 37 mmShaft diameter 3,17 mm Weight 220 g
It would seem that they are a good motor. I would assume that the other Graupners would also be excellent motors in the right situation, depending on model type and size.
Peter.