29 Nov. 1975|
Hand launched balsa glider plans,modern wooden table plans,free woodworking plans toys - Review
C-grain or quarter-sawed balsa, as shown here, is very resistant to bending across the width of the sheet. The design of the glider, however, is only one of many factors required for success in IHLG. Transfer the outlines to the balsa by tracing around the template with a ballpoint or sharp nylon-tip pen. Before shaping the top of the airfoil, sand the wing to the proper thickness at each station, as shown on the plan.
Balsa model hand launch glider Manufactured by Eagle Wing Model Aircraft in Portland, Oregon.
MATERIAL CHANGES: For at least 80 years, balsa has been the material of choice for hand-launch gliders. The Core: For tip-launch gliders, the most popular core choices are insulation foam, Spyder Foam, and Rohacell foam. If the launching was the slightest bit off, a collision with a parked helicopter was inevitable.
But, just as the event has dramatically changed from the traditional javelin launch to tip launch, construction materials and techniques are also starting to change.Javelin-launch gliders typically measured 16 to 22 inches in wingspan and weighed roughly an ounce. The cloth or tissue pieces are placed on a piece of thick Mylar and wetted out with epoxy resin, and then the excess resin is blotted off. Composite glider wings require an investment in both time and money, as does any new technology.
It may take a little sanding to get it into shape but the payoff is a beautiful little balsa glider that will give you, and any youngsters who may be around, a day full of old fashioned fun.
However, by using a six-panel wing and tapering each panel, you can approximate an elliptical planform. Next the core is positioned over the bottom skin and then the top skin placed on top of the core.Another piece of Mylar is draped over the assembly, and everything is placed inside a vacuum bag. For some of us, the feel of a razor-sharp plane on a piece of C-grain balsa offers more rewards then messing with epoxy and strange plastics. Serious fliers produced large batches of gliders knowing that some would be broken, some wouldn’t fly well, and others (always the good ones) would be lost in thermals.
Dihedral joints were reinforced with carbon-fiber tow on the top only to reduce bending on launch.
With any type of construction, keeping accurate weights of each part as you build is important.The other glider I examined was British glider flier Mark Benns’ Spin-Up 1000.
The vacuum is held until the epoxy hardens.The result is a stiff wing that won’t flutter on a hard launch and won’t change between contests. More importantly, you can make another one just like it without spending weeks searching for a perfect piece of balsa.Matt Gewain has created an excellent tutorial about vacuum bagging, which can be seen on the CST website. Consequently the tip-launch gliders last longer, allowing more time and money to be invested in construction. For faster and more accurate production, a jig could be devised to hold a router at the correct angle to shape the sloping rear of the wing airfoil.Jim Buxton's tip-launch glider sports an insulation foam wing, skinned with two layers of lightweight glass cloth.
This also means that models can be more accurately constructed.Although balsa is still a viable choice for larger tip-launch models, some modelers are exploring other options for wing construction. Although the choices vary in the materials and building techniques used, they all utilize a stressed-skin structure.Unlike a solid balsa wing, a stressed-skin structure uses two different materials, each to its best advantage. Using a CNC mill allows the wing core to be cut as a single piece and also permits a curved planform.Carbon-fiber cloth is oriented on the bias for maximum torsional stiffness. Many RC models utilize a foam core covered with thin-sheet balsa or even heavy plastic film. Others use fiberglass, aramid, or carbon fabric to handle thinner airfoils and higher flight loads. Closely spaced balsa ribs provide the core function.More recently, thin, hard aluminum foil, fiberglass cloth, or carbon fabric have provided the stiff outer skin, either over a fully sheeted wing or a foam core.
In principle, even a traditional stick-and-tissue wing is a stressed-skin structure, with the taut tissue adding both bending and torsional strength to a lightweight balsa framework core.