Resistance dynamometers with model clamps measure the force of ship model hulls.
Our resistance dynamometers with integrated pneumatic model clamps measure the resistance force of model hulls of surface vessels installed in the towing tank. They can also be used during propulsion tests with ship models for applying and measuring the towed force in combination with measuring the model propeller(s) thrust and torque.
Resistance force is measured via an exchangeable loadcell incorporated within the balance with damping. The balance is operated in combination with a model clamp such that appropriate rated loadcells can be selected and fitted for the estimated test loads. The model is clamped and released via the pneumatic clamping / measurement system. This allows the clamping of - the model during acceleration and deceleration, only releasing once the model and carriage are at test speed. This ensures the force is measured accurately with the suitably sensitive loadcell, while protecting the instrument during the acceleration and deceleration phases.
The ship model is connected to the resistance dynamometer via a towing shaft that is mounted in the axis of the propellers shaft. The towing shaft can be set with the model trimming but it is free in heave and trim.