Bug4 & Bug2 Page

by Mike Sandlin

Last Update: Feb. 10, 2004 (New file, b4z4.EXE)

Almost five years after first flight, the Bug2 and Bug4 are still soaring and serving as an example of how ultralight sailplanes can be simple, practical, fun and safe. Some of the "firsts" of these elegant biplanes include the following:

• Self launch soaring by rolling down hillsides (on a regular basis)
• Self launch training by rolling down hillsides
• Car top transport on non-specialized racks (by a wheeled sailplane)
• Construction (of a wheeled sailplane) from readily available materials without special welding, machining, or molds.
• An empty weight (for a not foot launchable glider) substantially less than the ultralight regulatory weight limit.
• Posting of the complete technical drawings of an aircraft on the Internet, freely available in the public domain for downloading and study.

Bug2 and Bug4 have demonstrated casual and comfortable airchair soaring, drogue chute landings in small fields, and novice instruction on training hills. They have been towed by trucks, winches, and ultralight airplanes. When a landing area has been available near a hilltop launch, we have taken turns making as many soaring flights as we have desired by roll launching, soaring up, and then landing back where we took off. The Bugs have soared high, if not far, and have always returned for a safe landing.

Unconfirmed safety design aspects include:

• Extensive frangible structure around the pilot for crash impact protection
• 4 point safety belts
• Inherently slow flight to minimize crash energy
• A hand deployed emergency parachute which is intended to bring the glider and pilot down together, tail first, so that the pilot is protected by the tail and wing structure during the parachute landing

Bug2 and Bug4 performance has not been measured but seems to be about the same as a single surface hang glider. Currently I am flying the Goat, my monoplane airchair design, and my biplane flying has come to an end for now.

I have flown the Bug2 and Bug4 for soaring only. I do not perform aerobatics. I consider the structural redline (maximum safe airspeed) for my flying to be 45 mph.

For liability reasons I do not provide plans or give advice, I only describe how I do things. My aviation activities are noncommercial and nonprofessional.

You can go to: B4 &B2 in Action

Drawings, as a Zip file download (b4z4.zip):

Bug4: Bug 4 was intended to be an improved version of Bug2, and I consider it superior.

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