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About Center of Gravity

All Terrain Vehicle Performance Chart

The lift fan is attached directly to the crank!

The thrust fan is belt driven from a pulley set above the lift fan.

The thrust  propeller delivers approx. (120lbs of thrust)

And now "hovering," actually cleaning the street!

Hovercraft Education

Principles of Hovercraft

When the subject of hovercraft comes up in a conversation, often the first question I hear is, “What is a hovercraft?” That question is usually followed by an awkward explanation, such as, “Oh, that’s the thing that flies on air or something . . . I saw one a few years ago, and, man, was it noisy, and it looked like it was out of control all the time.” This intriguing description frequently triggers interest and curiosity, and a desire to know more about this amazing machine. Following is a simple explanation about the hovercraft and its capabilities and special features.

Hovercraft and the airplane have similarities. There is a roll, yaw and pitch associated with a hovercraft, not unlike an aircraft. It is not critical to use the dynamics of math for the design, although some need to be applied. It does not fly high enough to be significant in a roll, yaw, or pitch scenario, although it can be precarious. If an inexperienced flyer is involved, it is possible to cause severe damage to the craft, other objects, and possible injury or death to the pilot and passengers.

A hovercraft is affected by wind, which can be calm on any given day; however, on that calm day, the hovercraft is affected by the ground affect. It is the surface wind created by pressures in the atmosphere. On a hot day, the molecules in the air are thinner and it takes a much greater effort to accomplish a task. On a cold day, the hovercraft almost seems to fly itself.  Ground affect is the densest air, since it is closest to the ground where all the affects of gravity pull the hardest. Ground affect is on an average of about 3 to 6 feet above the surface. So if you think something is wrong, or the hovercraft feels a lot different one day than another, take a look at the barometric pressure and the sky. Keep a log of the days it flies the best. It can be frustrating wondering why the performance changes so drastically.

Consider the transition of flying from land to water; the temperature causes a drastic change on the performance of the hovercraft and the operator instantly experiences a completely different flying aspect. This transformation is similar to an airplane taking off on water; it goes from friction to frictionless. On a river or stream, ground affect follows the river’s motion. The flowing ground affect, and not the current, affects the hovercraft. Considering that the speed going downriver is increased by ground affect, it is apparent that the reverse is true when going upriver; the speed is decreased, not unlike having a tailwind.

Hovercraft fly on a cushion of air supported by low pressure and high volume airflow to the plenum (curtain, bag, fingers, etc). This airflow is supplied by an independent source of power - one engine for lift and one engine for thrust, or an integrated system where one engine supplies the power for both the lift and thrust.

The hovercraft flies on air, and has a ground pressure of less than a pound per square foot on most small hovers. It is environmentally and ecologically friendly because of such a soft footprint on the surface that it flies over. It is also quite user-friendly and will give a smooth and comfortable ride when adapted to the specific conditions of the area in which it is being used. Harmful effects are virtually zero where the vegetation, tundra, lake, riverbanks, beaches and mudflats are concerned. Bank erosion is kept to a minimum due to the low wave height. Once the hovercraft clears what we call “the hump,” the craft’s footprint doubles in displacement, creating a very low pressure per square foot compared to a boat that remains in a constant displacement position in the water.

Noise associated with a hovercraft has always been a problem. The new age hovercraft manufacturers have begun to use new technology to make the craft quieter. With the new 4-cycle engines, hovercraft noise decreases considerably and passengers can carry on conversations without yelling or using earmuffs or earplugs.

Learning to fly a hovercraft and getting to know its characteristics is like learning to drive any other vehicle. Hovercraft are subject to camber - the rise and fall of the surface upon which it flies. As a bubble floats in a level, so does a hovercraft float on the surface of the earth. Training is necessary, but unlike other vehicles, it can be accomplished in just a few hours, and can be fun and rewarding.

Hovercraft have numerous functions.  Many private and commercial operations use them for environmental studies, surveying, fishing, hunting, transportation, fish and game studies, mining, tourism, charters, and many other things. Search and Rescue operators are using them more and more for flooding, ice, and debris-laden areas, where other types of craft could not penetrate. Negative effects of the hovercraft on the fragile environment is nearly non-existent.

Licensing a hovercraft is no different than licensing a boat; please see the legal information provided on this site.

Getting a new paint job for 2004

And some needed repairs

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