Paramotors & ultralights

Normal planes use a somewhat flexible, but ultimately rigid airfoil + frame. This page is for planes which build their wings out of flexible fabric.

Ultralights, Hang Gliders, Powered Kites

This class of vehicles stretch fabric on some type of frame, and typically fly with a large hanging open cockpit underneath this space-frame wing. The degree of coverage and support for that wing covering varies. For some ultralights it may be treated as little different than sailplanes that use stressed Monokote, a full-fledged tension skin. For others the airfoil may be one-sided ('hollow'). At the extreme, the Rogallo wing craft, the airfoil is simply a wide delta of compression ribs with a loose single-layer sheath of fabric; The air pressure on this sheath holds it open.

Typically these are somewhat inefficient compared to their rigid-winged brethren, and aren't capable of flying for as long. They are a lot easier to pack up into a small space, however, and the simpler ultralights are essentially similar to tethered kites, but with a propeller. The more complex, larger ones may progressively add features until they turn right into a normal fixed-wing plane, albeit one with a lot of wire support and a large undercarriage.

Models

• WildRC IFO Mini - 21 dm^2
• BLAC Gymallo - 28 dm^2
• WildRC T-IFO - 29 dm^2
• WildRC IFO Mk3 - 38 dm^2
• RC Air Kite
• Robbe Skyflex - wingpan 1.8m
• Electricflights Hawkeye - 142 dm^2
• Electricflights Hawkeye 24 - 223 dm^2
• Electricflights Hawkeye 28 - 260 dm^2
• Hangar 18 Breeze (ext)

Prototypes

• UKHAS Glider Project

Links

• HAWKEYE The Portable Aerial Photography System - Joel K. Scholz
• GoFlyKite Products - The most prominent of the Singapore manufacturers of night-flying "LED Kites", very popular in that country as a competitive pastime of acrobatics and style/design. Their high prices make sense only in that context.
• Premier Kites and Designs' VR line - A series of acrobatic kites which couple with a vectored-thrust power pack

Paramotors

Straying even further from the rigid wing concept are paragliders and paramotors by removing the wing spars. These use a specific design of parachute that revolutionized the practice of jumping out of planes. The ram-air parachute, or 'parafoil', holds its shape purely under the influence of air pressure build-up and tension, and it is used to build cells which deploy as a remarkably aerodynamic gliding wing, with lots of forward velocity. In manned parachutes, this forward velocity is used to steer left and right, and to 'flare', essentially pulling up on the stick and accepting some more forward horizontal speed in exchange for bleeding off vertical descent speed.

Paramotors take a parafoil and add a caged, fixed-pitch propeller. They tend to be even less efficient than the utlralights, necessitating short flight times per battery weight, but have an even more extreme portability for their size, and excel at slow, steady flight, even during extreme diving and climbing maneuvers. With a hanging payload, battery, and motor, there is an extreme degree of pitch/throttle coupling and yaw/roll coupling. The extreme speed limitations of a paramotor do make them difficult to operate in a significant headwind.

Vehicles like this may be practical for those without expertise or interest in complex fixed-wing constructions. They are capable of STOL, and can be packed into a very small volume for travel. Nonrigid-winged vehicles move slowly and tend to have relatively safe crashes for all involved, and may have regulatory advantages over faster fixed-wing crafts.