Resistance Dynamometers Lab

Watertight Propeller Dynamometer

The Watertight Propeller Dynamometer of high capacity is sealed against pressure of up to 1 bar above atmospheric pressure and against relatively high vacuum (1 bar = 10 to the power 5 N/m2 = 0.1 MPa). Idle friction of the measuring shaft is small despite the use of sealing rings and is approximately 0.3 Nm for dynamometer and 0.4 Nm for dynamometer. The dynamometer can be used also for propulsion tests with relatively high torque and thrust values in ship models under water. That has slightly larger dimensions, but is of similar appearance. It is thus suitable for use in the measuring section of cavitation tunnels, as an inner drive dynamometer in ship models or in dummy bodies mounted in the measuring section of a cavitation tunnel.

Open Water Podded Propeller Dynamometer

The necessity to support the international ship model testing community with the provision of a Podded Propeller Dynamometer has therefore become imperative the need to carry out tests to establish the hydrodynamic and operational advantages of podded drives over conventional propulsion systems is a worldwide requirement and urgent. A variety of podded propulsion drive systems are increasingly being introduced into current and future generation designs of cruise liners, ferries, vessels operating in ice conditions, shuttle tankers and specialist multi-hull vessels.

Features:
The use of a single propeller fitted at either end of the pod or a duel  propeller combination rotating in the same direction. The standard gearbox suitable for a Maximum Torque for two propellers 15Nm at each shaft with a combined torque of 30Nm or a single propeller with a max torque of 30Nm
Torque and thrust strain bridge sensor telemetry units available for each propeller (single supplied as standard);
A compact podded propeller dynamometer with driveshaft, bevel gears and two output shafts to which propellers can be fitted if required. Please note the propeller shafts can be designed to suit customers requirements, however in view of the high forces generated within the unit,there is a requirement to use low-mass propellers and not to exceed recommended limits;
Height and Angle Mechanisms: these can be supplied with frame suitable for use in a towing carriage or a mounting system designed to fit the equipment for use with in a cavitation tunnel allowing adjustment in height/depth as well as adjustment in Roll, Yaw and Pitch Angles.
Drive motor and control with speed output signal for data acquisition if required
Combined with an three component balance facilitating measurement of forces drag/unit thrust Fx or lateral force Fly as well as Yaw moment Mz in open water testing
Speed Display Rack: this can be used either with the inline encoder or drive output to display the propeller speed or drive speed.Please note that as the uses a 2:1 gearbox.

Ship And Yacht Model Balance

The balance is then connected to the model via a light weight carbon fiber composite free heave towing post, that has height adjustment as well as being free to heave, fitted with a linear transducer for the measurement of heave. The balance can be used in both a circulating water channel or suspended from a small towing carriage and can be used in both smooth water tests and tests in waves. The Dynamometer utilises three of our K&R ex-changeable load cells in a 3 component world balance arrangement for measurement of Resistance (Fx), Side Forces (Fy) and Yaw Moment (Mz). 

Contra Rotating Propeller Multi Purpose Propulsion Dynamometer

The Contra Rotating Propeller Multi Purpose Propulsion Dynamometer is a generic design for use either within a large Cavitation Tunnel or within underwater models in the Towing Carriage. The design greatly simplifies the transmission of power to the output shafts and reduces the number of moving parts (and thus generated noise) considerably. In this case is to be supplied for use in both facilities with the appropriate equipment and accessories including a separate water cooling system for the integral motors. The new CRP dynamometer is based on the Dynamometer principle of integral motors in the gondola, however with higher ratings to meet our customers requirements.

Watertight Model Self-Propulsion Propeller Dynamometer

This additional sealing equipment can be taken out easily and can be replaced by the sealing arrangement for use in ship models in the towing tank in order to reduce friction So if the additional equipment for use of the dynamometers in a cavitation tunnel is ordered, the dynamometers are also suitable for use in ship models in a towing tank. In the first case, they are provided only with a sealing arrangement suitable for sealing against water pressure whereas in the latter case, they are supplied with additional equipment that seals the propeller dynamometers against relatively high vacuum and against pressure up to 1 bar above atmospheric pressure. 

Open Water Propeller Dynamometers

The propeller dynamometers are new designs to replace earlier dynamometers only adjustments to the inclination of the propeller shaft could be made, but with the introduction of the adjustment of propeller shaft height can also be achieved. Depending on the maximum capacity of the drive motors, the maximum torque ratings, and consequently the diameters of the propeller shaft ends, are different. The capacity of the drive motors of the same whereas that of less. Apart from the different arrangement possibilities,the technical details of all essential parts of propeller dynamometers are identical, with exception of the capacity of the drive motors and the maximum load ratings in respect of measurement of torque and thrust.

Traditional 3 Component Resistance Dynamometer

Equipment is designed for the measurement of resistance and alteration of draught and trim during tests with relatively small ship models on smooth water and in waves.

Electric Open Water Propeller Dynamometers

The dynamometers can be supplied with the standard height of the vertical streamlined profile or with an increased height of the vertical streamlined profile as described below. The three dynamometers are of the same general type but differ in size and capacity as shown below. Full technical details of the dynamometers are provided below.

Multi Component Balances

However it is suitable for smaller ship models than would otherwise be used. The balance is of the same general type as the balance. 

Electric Single Component Balances

Both balances serve mainly for measurements of forces acting on models which are either towed with the help of a towing carriage through a towing tank, or which are tested in a circulating water channel.
Both balances have the same general design but a different capacity as stated below. Pressure changes have practically no influence on the force measurements. The pressure surrounding the balance can vary between high vacuum and 1 bar above atmospheric pressure.

CRP Dynamometers

It is therefore possible to control the speed of the forward and the rear dynamometer independently from each other. All 3 CRP dynamometer types have separate driveshafts for the forward and rear dynamometer to facilitate the connection of two motors. Alternatively, the two driveshafts can be connected through a gearbox normally with a transmission ratio of1:1 so that it is possible to drive both the forward and the rear dynamometerat the same speed in opposite directions, from one motor.

Resistance Dynamometers

Resistance dynamometers combined with model clamp are of the same general type, but with different capacity. They are also used during propulsion tests with ship models for applying force in addition to the propeller thrust, which is often necessary for the test program. They are designed for the measurement of resistance of ship models, which are towed by a towing carriage.