[quote]ORIGINAL: somegeek
My question is, do you set aside heavier and lighter balsa for different builds? I could see this lighter stuff working well for a smaller 1/2A build but don't know where you would want to use this really lightweight balsa?

Absolutely!-balsa selection is the basis for effective sratch building. Not only by selection of weight, but also by cut.....straight, random or quarter grain-or as it is expressed in the USA.....A-grain, B-grain and C-grain stock. All my models are built by first selecting the wood for both weight and cut. To that end-at any one time I probably have several thousand dollars of balsa wood in stock-ranging from 4-5lb cu ft (v.light) up to 10-12 lb (heavy).
Given that I am largely a competition F/F flier, with only an occasional foray into radio-I probably spend more time and effort in balsa selection than the average R/C flier. Ditto for C/L competition flyers-especially those flying team race-where the wing wood selection will determine whether you end up with a winner or an also ran.

To give some concrete examples, among the many contest classes I fly are P-30, Coupe d'Hiver, and Hangar Rat. The first two have minimum airframe weights of 40grams and 70 grams (less rubber) respectively. poor or indifferent wood selection can result in a model 50% overweight-and a performance not much better than a flying brick. Hangar Rat is a very simple indoor class-the first one i built-out of the scrap box-weighed 10.2g-the second, doing some reasonably careful wood selection-but not using any ndoor grade wood-was 6.5g-thats a nearly 40% weight difference-simply on wood selection. The difference is a model that flies on 3/32" rubber rather than 1/8"-and takes a lot more turns for longer flight times.

Yes wood selection is important-and so is glue-and covering material choice for weight control.

The Indoor fliers go a step further-and select for stiffness as well as density-and in the tiny tiny %s of balsa suitable for Indoor wood-it costs more than gold on a weight basis!

'ffkiwi'