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Building Light for Better Performance, Part II

Last month, we discussed the advantages of building lightly when designing or constructing a model plane. This month we look into how one can adopt lightweight building practices when constructing that slick new kit. The ideas presented here are from a series of articles by Clay Ramskill.

There are two parts to building lightly: 1) knowing what to build with, and 2) knowing how to put those pieces together to create a lightweight but strong structure. Let's look at each piece of this puzzle separately. First, building materials:

Once we've chosen our building materials, we now need to consider how to put them together to make a better-flying, lighter plane. Here's where building techniques come into play. If you're scratch-building, it's only natural to come up with your own construction design. Kit-builders may find that they can trim their plane by modifying kit parts (lightening holes, etc) or by replacing certain pieces altogether, replacing them with parts traced on lighter wood. Here are some tips to try on your next plane:

Most model designs are heavily overbuilt - but it's always going to be up to you to decide what is overbuilt and what isn't. We're not rocket scientists (and neither are the designers!), so don't be afraid to ask an experienced modeler about modifications that you're not sure of. And don't be reluctant to experiment! If a ply former seems heavy, try making a duplicate of balsa ply, and compare. Try doing a built-up stab (they're easy, really!) and compare weight and stiffness with the solid version.

Keep weight in mind constantly as you build. Keep the following adage in mind: build strong where needed, and lightweight everywhere. Pay careful attention to the parts of your plane where strength is most important (center of the wing, landing gear attachments, engine mount, wing mounting, etc). Question the design of the kit you're building: Would EZ hinges be lighter than the conventional hinge-pin type? Can I use shorter (lighter) bolts than the ones the kit supplied? Can I trim the ends off the engine mount? Could I replace this lite ply doubler with balsa?

An ounce here, a half-ounce there - it all adds up fast! Here's an experiment: try adding 6 ounces to the CG of your favorite plane sometime, then go fly. Not nearly as much fun, is it? Now consider this: just about every glow kit out there could easily have 6 ounces removed from the structural weight with NO measurable loss of strength. It's worth thinking about...


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Next: Until Next Month... Up: Front Page Previous: Club Instructors are:

Craig Kulesa
Fri Dec 4 18:51:34 MST 1998