X Gliders

Last Update: January 4, 2003 (added a Sundog photo)

Sundog

Sundog was a rigid wing I built to test the usefulness of flaps on a hang glider (see Hang Gliding, February, 1991). This version has full span flaps which fold under the wing for transport. There are spoilerons on the top surface of the wing for turning, actuated by side motion of the hang loop. The flaps were pulled down by a rope, just like the modern D-cell rigid wings of today. The tail surfaces are just fixed stabilizers. It was too heavy (90lb.s) and the static balance was non-existent (special launch procedures required), but it was fun to fly once you got it in the air. Full span flaps allow simple, easy landings, very similar to a drogue chute.

Sundog with ailerons

Skypuppy

Skypuppy was the predecessor to Sundog, my first rigid wing with flaps. Turn control was by rudder lines attached to the hang loop (no ailerons), with large flaps for take off and landing. The area was only 100 square feet, so the flaps were needed! It was too small to soar much, but everything worked well (see Hang Gliding, June, 1988).

Litewing

The Litewing series attempted to turn back the clock to the era of 35 lb. hang gliders. This is hard to do with today's performance expectations, especially considering my crude sail making, but it was fun and adventurous. If you are going to be a hang glider test pilot you must have heroic legs!

Litewing at Torrey Pines,California

Now the tail is attached to the main sail, as it was on my old Aolus. All the tailed gliders had strong trim forces; they always wanted to go fast when banked and required some pitch up force to stay slow.

Sundog launching at Soboba, California

This was the aileron version of the Sundog. These were up-only ailerons, actuated from the hang loop, then returned to neutral by a bungee cord (like the spoilerons, which came later). A right roll is being commanded here. A good system, but I wanted bigger flaps.

Test Flight

Experimental gliders are tested on training hills according to the rule: don't fly any higher than you are willing to fall. I also went out for testing on one of the fully equipped test trucks, which is not expensive and provides a lot of basic confirmation (both good and bad).

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