The "LeDuc Line Shuttle" can be used to carry payloads such as cameras, etc. up and down a kite line. The Shuttle allows kites to be launched to a stable altitude prior to lofting the payload. The payload can be raised and lowered up and down the line to any altitude without having to adjust the kite flying altitude. The Shuttle requires no additional rigging to the kite or kite line allowing you to attach it to any kite already in the air. The Shuttle is propelled up the kite line by pulling monofilament fishing line from a small reel mounted to the Shuttle, and does not require electrical power or motors to operate, making it very compact and light weight.
The major components of the Shuttle consist of:
- Power Shaft
- Traction Wheel
- Power Reel with Power Line (monofilament fishing line)
- Rigging Pulleys (front and back)
- Line Alignment Clip
- Payload Arm
- Ground-Based Launch Reel
The Frame and Payload Arm are made primarily from carbon fiber and fiberglass materials.
The Traction Wheel is made from maple and is cut using a hole saw. The Power Reel is a standard fishing line spool available at most sporting goods. The Traction Wheel and Power Reel are attached to each other and mounted to the frame on a vertical shaft using ball bearings to reduce friction. The Traction Wheel is allowed to float up and down on the shaft to allow proper vertical centering on the kite line.
The Power Reel diameter must be larger than the Traction Wheel diameter. This is required to provide the necessary mechanical advantage for movement up and down the line. Ive found an optimum ratio between the Power Reel and Traction Wheel diameter to be 1.5:1. I use a Power Reel diameter of 3.75 inches and a Traction Wheel diameter of 2.5 inches. This ratio provides an approximate 2:1 mechanical climbing advantage allowing it to be raised or lowered very quickly. This means that for every 1 foot of line transferred onto the Launch Reel results in the Shuttle climbing 2 feet up the kite line. The Power Reel is loaded with 1000 ft of 8 lb monofilament fishing line. This allows you to loft the Shuttle approximately 667 feet up the line by pulling 333 feet onto the ground-based Launch Reel.
The outer edge of the Traction Wheel must be routed to a concave shape to keep the kite line centered on the Traction Wheel and to keep it from walking off the edge of the pulley as it turns. I use a concave radius of approximately 0.2 inches. A Dremel tool or router may be used to achieve the concave shape on the edge of the Traction Wheel. The Traction Wheel finish must provide enough friction to allow good traction to the line, but not too much friction as to impede smooth assent and decent up and down the line. Ive found it best to have a smooth, hard finish such as polyurethane on the Traction Wheel.
The front and rear Rigging Pulleys are mounted approximately 4 inches on either side of the Traction Wheel center line. The vertical adjustment of the Rigging Pulleys is important to reduce line friction as the Shuttle is moving up and down the line. The front Rigging Pulley (closest to the kite) should be rigged to be slightly below the vertical centerline of the Traction Wheel (approx 0.05 inches below center line). The rear Rigging Pulley (toward the ground) should be rigged to be slightly above the vertical centerline of the Traction Wheel (approx 0.15 inches above center line). This vertical rigging tends to spread the kite line as it enters and exits the Traction Wheel and helps reduce friction. Note that too much vertical spread between the front and back Rigging Pulleys results in unwanted friction and force on the Traction Wheel and makes it hard for the Shuttle to return down the line by itself.
The Line Alignment Clip is used to keep the Kite Line and Power Line close to each other as the Power Line exits the rear of the Shuttle. This helps reduce the force on the frame as the Kite Line and Power Line split away from each other at higher altitudes. Without this clip, tension on the Power Line may cause the Frame to flip around the kite line resulting in tangles between the lines.
Line friction is a major factor that needs to be managed in order to insure smooth assent and decent. Friction becomes a major issue with increased kite line tension. Ive found that keeping the line tension to no more than 15 or 20 lbs helps insure the Shuttle will return down the line on its own. Ive found that flying the rig with a smaller kite in stronger winds helps manage line tension. I use a Flowform 30 for winds up to ~15mph and a Flowform 16 for winds above that. Key design features used to manage friction are:
- Concave shape and finish of Traction Pulley
- Vertical alignment of front and rear Rigging Pulleys
- Use of ball bearings on all rotating parts