The total weight of the complete model is only 6 oz., and in making the machine every effort should be made not to exceed this amount.
[Fig. 135] shows a model hydro-monoplane in perspective.
CHAPTER XIII
Compressed-air Engine
for Model Aeroplane
Signs are not wanting that compressed air as a motive power for model aeroplanes will become equally as popular as the twisted skein of rubber, which has practically held the field since it was introduced about the year 1870 by Alphonse Penaud.
One of the chief disadvantages of the rubber motor is that experiments of a full-size scale nature cannot be undertaken, owing to the length of frame required in order that the necessary power and duration of run may be obtained, and also owing to the disposition of weight, and consequently of the centre of gravity, not being tantamount to that obtaining in full-size practice. With a compressed-air plant these disadvantages are eliminated, since the weight can be kept well forward, thus making possible the designing of a model which represents in essential proportions a full-size machine.
Particulars are here given of a highly successful plant, for which the machine described in the next chapter was especially designed. Several of the illustrations in this present chapter are exaggerated to render the construction clear, and it is thought that the details given will be found comprehensive.
Fig. 136
Fig. 137