How to calculate draft of the screw

It is possible to define draft of the screw on plane model using the dynamometer measuring tool. Depending on the necessary accuracy of measurement it is necessary to use dynamometers of various designs. For determination of draft of the screw of model of the helicopter it is better to use lever scales with a set of weights.

It is required to you

• It is required: a dynamometer mechanical with the indicator of hour type, a dynamometer electronic digital, scales lever with a set of weights.

Instruction

1. For determination of draft of the screw of model of the plane by means of a mechanical dynamometer fix it on a plain smooth surface. Attach completely collected and installed on the chassis plane model to draft of a dynamometer. Start the engine of model and take readings from the dynamometer indicator. Repeat this operation, every time changing engine speed, achieve the maximum draft of the screw. This way has the low accuracy of measurement which is limited to the accuracy of indications of a mechanical dynamometer.

2. For obtaining more exact indications use an electronic digital dynamometer. Fix it on a plain horizontal surface. By means of draft attach the plane model installed on the chassis to the dynamometer sensor. If this type of models has no wheel chassis (model of a seaplane or type "the flying wing), it is necessary to fix reliably it on the special cart. Height of the cart has to provide free rotation of the screw of model. Start the engine of model and, changing the frequency of rotation of the screw, determine the maximum draft of the screw by the dynamometer display.

3. For determination of draft of the screw of model of the helicopter establish lever scales on a plain horizontal surface. Counterbalance scales by means of adjusting small weights. Weigh model of the helicopter and remember its weight. Reliably attach model to a framework of the measuring mechanism of scales on which plates lie. Start the engine of the helicopter and, regulating engine speed, force the helicopter to rise as much as possible up. If the plate in which the model is fixed reached the top limiter, add to it the weight until she does not get up in average (zero) situation. Be careful – the rotating screw of model can strongly wound! Kill the engine of model, get and calculate the weight of the weights lying in a plate with model. To the received sum add helicopter weight. This result will also be value of draft of the screw of model.

Author: «MirrorInfo» Dream Team