"Models", page 1
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Making of "Airwave" Not finding a radio controlled model sailboat of the design I wanted, which was of a stand-off scale 38 ft. gaff-rigged ketch, I decided to make my own. Originally thinking it would be easier, I decided on a 'glass/epoxy hull so I made a foam/fiberglass plug of hull, then a female mold from it, then molded the hull. All this proved to be more work than it was worth for a one-off hull, but the experience was good. The fiberglass covered balsa deck enclosed seven airtight compartments leaving two compartments for the equipment, that although closed while sailing, have a small outside air tube to the cabin area. The rest of the wood used is mahogany, spruce, and bass. The main and mizzen spars are a laminate of bass (center) and spruce (outer). The pulley blocks and other miscellaneous hardware, with the exception of the bronze prop and brass turnbuckles, were homemade. The gaff-rigged mainsail, mizzen, and club-footed staysail are controlled from a modified "ACE" heavy duty servo and limit stop switches on the control lines. The flying jib is controlled by another modified servo and limit switches. Other channels operate the rudder, aux. motor, and lights. A 7-cell ni-cad battery (1500 ma, presently) is used with a 5V. regulator dropping the voltage for the receiver, servos, and lights. The radio was an old "ACE Digital Commander" 3-channel radio, built from a kit, that I modified with a new case and controls, some homemade circuits, and narrow-banding, to a 7-channel transmitter. The receiver is a "ACE Silver Seven" build from a kit, with "ACE Radio" servos. Five channels are currently used. I used a "Grimes" 5-pole electric motor for the direct-drive propulsion to a 3-blade bronze prop in case the wind dies. (Motor obtained from a "Grimes" 24V. aircraft rotating beacon and uses only about 175 ma of current at half power, which gives a nice scale cruise speed.) A homemade speed control gives variable speed forward and full reverse, and runs from the full battery voltage. Specifications: Length O.A. 45.5 in. Draft 6 in. Length, Deck 40.5 in. Sail Area 636 sq. in. Length W.L. 33.5 in. Displacement 15.5 lb. Beam 12 in. Ballast 5.5 lb. "Airwave" sails very well and tacking requires re-adjustment of the jib only as the other sails are self-tending. For some simplicity, automatic running backstays help with the mainmast stresses. The 5.5 lbs. of ballast help keep the boat upright. Lights include a cabin light, nav. and steaming lights, all radio controlled. |
Pictures on the following 3 pages.