Pete's  Planes

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Scaling, Model to Model

to obtain the same appearance in flight pattern

If we scale-up a model to twice linear size, and choose the weight to give twice the stall speed, and install a power unit which produces twice the maximum speed, then the two versions will fly at the same apparent speed.

They will also have the same roll rate and climb angle.

When the larger model is flown at twice the distance from the pilot, it will present him with the same dynamic appearance as the smaller model. The flight pattern will look just the same.

TABLE 1 presents the data to achieve this relationship, for a range of scale ratios.

Each vertical column defines a model scaled from the datum model. More columns can be added, when required, for other ratios.

For the mathematics underlying table 1, see appendix !

TABLE 2 gives an example of scaling-up an IC powered model. The .60 cu inch motor is presumed to have four times the power of the .15 cu inch motor.

TABLE 3 gives an example of scaling-down an electric powered model.

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Where the speed of the derived model is required to be higher or lower than the scale speed, this same approach can be used to calculate consistent values for  size,  speed,  power,  and weight.

The possibilities are too numerous to tabulate. Each case would have to be considered separately, and the process of appendix 1 re-run.

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