Here is a “Rahm” winch that I mounted on an aluminum frame with wheels so I can move it around easily. This has a ford long shaft starter motor that has been beefed up with four brushes and four field windings for high torque. The winch comes with the brake arm, foot switch, battery cables and turnaround.
I have also installed a set of “Real Balls” ball bearings for the shaft for less friction. This bad boy gets it done!
The battery I use is a “Trojan Marine” SCS225 deep cycle 130 amp hour capacity, 7.1 hours run time @ 15 amps. I also installed a high amp switch ( red) for emergency shut off. The two “L” shaped pieces are for metal spikes, they hold the winch stationary. The line is Samson #30 braided nylon, rated at 330 lb. test. The drum holds enough line to go out 900 feet to a turnaround chive that is also staked to the ground.
We use a “bridle” for all our scale gliders. It”s made from sail boat hardware. The parts are, a quick snap caribiner with a eye, 36 inches of 1/4″ kevlar line, 2 welded 5/8″ rings, two 1/4″ inch copper swedges. The line is allowed to slide through the eye so as to keep even tension on the hooks.
Assembly: Slip the 1/4 line through the eye, slip 2 pieces of shrink tubing that fits over the swedges. Then slip the swedges over each end of the line. next put the line through the 5/8″ rings, then slip the end through the other side of the swedge and then crimp the swedges with a swedging tool, most marine hardware stores have one that you can use. then heat shrink the tubing over the swedges, whala! it’s done.
In this shot you can see the location of the tow hooks. We mount them about 2″ below the wing and 1/4″ to 3/8″ forward of C/G, the closer to C/G the higher the angle of attack on the launch.
In this shot you can see the location of the tow hooks. We mount them about 2″ below the wing and 1/4″ to 3/8″ forward of C/G, the closer to C/G the higher the angle of attack on the launch.
In this shot Mark is holding for Dennis, Mark keeps the wings level, when dennis sets up he will first take up any slack from the line. Then when ready he will say “Launching” to alert any one in the immediate area, then he will step on the foot peddle. Mark will let go with just a small amount of line tension, so as not to load up the line. You want to ROG (roll off ground), with enough line speed to keep the model flying and not stall it. Let the model run out about 15 feet before rising up. When you get to the top of the launch let off the foot peddle and just fly straight off the line. As you can see we don’t use a retrieval winch, we don’t want to risk catching it in the tail, and don’t want the additional drag on the launch.
Here Gene is launching his 1:3 scale ASH 26e. This model is around 24 lbs. you can see that the model is around 20 or so feet before he starts the climb. Letting it get airspeed first, if you don’t the model can tip stall and we don’t want to see what happens next! If you do stall immediately push the nose down to get control, and get off the pedal!
Here Mark is well on the way up. He also is flying his ASH 26e. We have launched this way for some time now with no miss hap’s. The trick is to keep your equipment in good working order. I replace the line every year. The advantage with a bridal is it allows you to place the tow hooks closer to the wings and center of gravity. Gliders that have a tall thick mid section at the wing root will tend to pitch to quickly if the tow hook is at the bottom of the model, thus causing the model to tip stall before it gets enough air speed, This is not good!
Dennis has a 1:4 KA-6, the tow hook was located on the bottom just in front of the wheel. He crashed it several times. after switching to the bridal, the model goes up like it’s on a rail. A lot of us don’t have the advantage of aero tow yet, so a good winch system is still a good method for launching