Design update by 4wings Hovercraft development

March madness design update!

In the last three month we got some information together which we want to share - tell you its worth it! But one after the other ... LOL!

Aeromobile Inc. made their first test-drive with the gimbal fan and it looks like they can circle around a peanut - guess this is the craft for all in rescue and close encounter situations -

I hope they keep us updated of their future success, so hover over to them @ http://www.aeromobile.com/amphibious1.htm

Aeromobil deisgned by Dr. Bertelsmann - US

F. Marc de Piolenc got in touch with us and after a few Mails he send us some specs for his new Gizmo - so all Sevtec user and racer - here is something which will hold your but up - or better hold more equal pressure in your skirt if you are at idle -

Marc's mail :
*Purpose:* An object of my invention is to provide a force or torque proportional to an applied, low, pneumatic pressure. This force in turn causes a change in the position of a device (hereinafter "splitter") tending to increase or reduce the pressure to the desired level. Another object is to provide a damping force or torque to limit overshoot and prevent oscillation. A further object is to provide all of the above in a device that is easily constructed and maintained, light and inexpensive, having only one rigid moving part. A final object is to provide the above features in a device that can be made an integral part of the plenum chamber whose operating gage pressure it controls. *Background:* In the course of the inventors work on integral lift/propulsion systems for static air cushion vehicles (hovercraft) and on liftoff aids for wing-in-ground effect vehicles (WIG), a recurring problem has been to maintain a constant pressure in a plenum chamber feeding a static ground cushion, while engine power and fan rotation speed varied in response to propulsion requirements. Problem: In small hovercraft at least, constant cushion pressure is usually sacrificed to simplicity of construction, and the solution adopted is a fixed flow splitter downstream of the lift/propulsion fan, which of course furnishes a cushion flow that varies with propulsion power setting. As a result, the necessity of maintaining a minimum skirt flow and pressure at minimum power setting ensures that excess flow occurs at higher settings, wasting propulsion power and causing handling problems. In the course of developing an automatic regulating mechanism for maintaining constant cushion pressure, it became evident that a sensor/amplifier/actuator (hereinafter actuator) was needed that was capable of producing large forces from small pneumatic pressures (in the ones to tens of pounds per square foot), and reliable damping responsive to changes in those pressures and to displacements of the actuator itself. As this need arises particularly in the case of small, amateur-built craft, the device had to be easy and cheap to build and to operate reliably without driver intervention. *Description:* The actuator consists of three plates--- -two fixed, one mobile ... guess what ... if you want to know more - give him a mail @ piolenc@reporters.net or visit his page @ http://www89.pair.com/techinfo/

David Carambat from http://www.industrialobject.com/hover.html send us his Design description for his "High Speed Hovercraft"

David's Mail
Design description: The Io Design, High Speed Hovercraft is a streamlined hovercraft based on proven technology. Its primary use is for comfortable, quite, long range cruising and brief overnight trips. This is accomplished by well padded seats and the application of sound deadening material placed around the perimeter of the enclosed cockpit. The streamlined, wide body shape of the craft allows for a narrow port and starboard bunk. Twin front seating is provided with additional space aft ( approximately 3' x 6') for seating or storage. The craft is designed for durability and damage tolerance by the application of a monoqouc type structure made up of encapsulated balsa/fiberglass reinforced panels. The balsa core panels also help to attenuate sound and vibration. Automotive quality safety glass is used for the windscreen which is provided with an electric wiper. Typical automobile fuel economy allows substantial range, this combined with the unique amphibious capabilities will allow unprecedented access to some of the most remote regions of the globe. This is the primary reason the design emphasis has been on reliability, all systems will be marine quality and special care is taken at all electrical termination's and pipe/tubing fittings. *Specifications:* Length overall = 20' - 4" (6.2 meters) Beam overall = 8' - 0" (2.4 meters) Height off cushion = 4' - 2" (1.2 meters) Weight = 1200 lbs lightship. Lift = 34" diameter fan powered by a 18 H.P. four stroke engine. Propulsion = 74" diameter propellor powered by a 80 H.P. engine. Fuel = 12 U.S. Gallons, unleaded (optional 24) Range = 300 Nautical miles at 50 Knots cruise. Payload = 735 lbs

Makes me feel better that i'm not the only one believing a Hovercraft has to be built after marine standard - equipment which is a lot more expensive than regular automotive. Check out his web site on his construction http://www.industrialobject.com/hover.html

Last not least here a response from Jim Lyne from the HCGB regarding the G forces in Hovercraft - they dropped it ... read on :

With regard to the cruising regulations. Yes we dropped reference to G
forces because it was felt by all scrutineers that it would be
impossible for amateur builders to even measure these let alone make
detailed calculations about them.

Hope this help clear the problem.

Best wishes

Jim Lyne
Secretary HCGB Scrutineering Committees