Model Aeroplane Notes

Manawatu Times, Volume 63, Issue 184, 6 August 1938, Page 10

Model Aeroplane Notes

(By 41 Joystick.”) Many people who saw the model aeroplane display at the Winter Show this year could not help but admire some of the very fine models displayed, but it is doubtful if they have any idea of the hours of work put into these machines by the boys. Apart from the actual building it is necessary that the competitors hunt all sorts of information concerning the correct details of the particular craft they intend to enter, and this is not always as easy as may be thought. However, by the time they have found out the Correct length, width and height of a macnine, the diameter of the propellers and whether the engine is radial or in line, etc., they have learned a good deal that is of value. This article is for future contestants, not only for the show, but for club | events. It is roally meant for the very (junior airmen between the ages of 9 and 1 11 years. There are the little men who (are too young to come along to the club (especially in the evening. The bigger [fellows are hard at it again, and the flight-lieutenants are training their I juniors to build and fly their models in I readiness for the inter-flight and interclub contests, and eo to the final contests on Labour Day week-end, when the North Island Model Aeroplane Association’s various record flights will, we hope, be lowered by some of our members. Now I will give the story of balsa wood. Balsa, the lightest wood known to man, is found anywhere in the tropies. The balsa we see in use, however, is grown in Ecuador, the little \ country on the west coast of South America, divided by the mighty ram-' parts of the Andes Mountains and crossed by the Equator. The trees have fairly smooth bark and largo brown leaves. JTkey may grow as nigh as 70 or 80 feet, | with trunks from 30 to 3G inches in diameter. The wood, half as heavy as cork, weighs only five to seven pounds to the cubic foot. Examine a piece of balsa wood under a microscope, and you will see that its structure resembles that of a honeycomb. It is made of a myriad of tiny cells. In balsa trees more than five years old the cell walls thicken and the wood grows heavier. For fchiß reason, balsa treeß over five years of age are nover cut for commercial purposes. A 25-foot pine ten inches square will weigh about 3251b5., whereas a balsa beam of these dimensions, however, will weigh about 75 pounds. In spite of its light weight, balsa wood has a strength almost half that of good spruce. It is easily worked, cutting like butter under a knife. Its consistency is something like rubber, for a piece of this astonishing wood can be compressed to nearly half its original volume between the fingers. (To be Continued Weekly.)