It appears from a very good source that Barry is not dead to the entire world of hovercraft. Angela Phillips from Amphibiuos Marine saw his corpse last weekend. Must have been just like a weekend with bernie?
The rest of us are still awaiting confirmation or as we like to call it proof of life. I'm thinking a banner flying from the craft that says, "you guys are all HELL, find your own parts!"
If you remember just one thing about Barry, let it be his own words.
The designer, a graduate in Mechanical Engineering from U. C. Berkeley, was designing and flying flexible wing hang gliders as early as 1960, which was the very start of the modern hang gliding movement. He designed, built and test flew snowmobile engined aircraft he called "ultra-light" (as registered with the FAA in the Experimental Category) in 1967, at the very start of the Ultralight aircraft movement. He has been plying the waters of (mainly) Florida and Puget Sound country in airboats and sevs of his design over the past 25 years, while serving as a staff engineer in aerospace, working on projects from rocket engines to spacecraft components and acoustics.)
A great picture of Bosworth and Barry cruising the Fantastic on the Skykomish.
Surface skimmers were developed over the years under names of Air Cushion Vehicle, ACV, Ground Effect Machine, GEM, Surface Effect Vehicle, SEV, and other names.
Serious development of these machines started in the early fifties in the English aerospace industry. These vehicles ultimately came to be called "hovercraft", and in the fifties, the vehicles were built by individuals in England and used in recreational racing. The racing craft, which were usually one or two place, were also called hovercraft and this term became generic for this type of craft.
I entered the picture in the early sixties, when after building a small air cushion platform I began doing numerical analysis on the small amount of information coming out of England on the new hovercraft. I found that while there were scholarly looking papers on the subject, things did not make sense. Analytical efforts were not directed in the area of making the vehicles more efficient, and less costly. These hovercraft required far too much power to fit into the real world and compete with even the expensive helicopter, except where the physics of scale effects (and possibly some government subsidy) allowed large vehicles a small niche in the scheme of things.
It became quite evident to me that the English efforts were directed at merely getting surface skimmers to work, and there was little effort in making them fit into the real world of commerce. The approach to design seemed to be "gadgeteering", rather than analysis of the designs as systems. The craft were built using aircraft technology, which worked fine on a 350 knot aircraft, but was far too expensive for a 40 knot surface skimmer.
In numerical analysis one builds a model of the system using mathematics and then applies estimates of the empirical part of the design (such as friction coefficients and diffusion losses). It is up to the designer of the vehicle to try to achieve these empirical aspects in real hardware (usually the estimates are too optimistic at the start), or at least approach their values as closely as possible. Then the next time, more realistic empirical input can be used to improve the next generation of vehicles. For instance, if this had been done in early English efforts such items as skirt elements that are pressurized well above cushion pressure, and peripheral jet surface skimmers would never have been built, as they cannot be made to work with reasonable efficiency in numerical analysis even with the most optimistic empirical input.
To this day, design of hovercraft suffers from designers that copy what they assume is mature technology, derived from the English efforts.
Design areas that should have been addressed by surface skimmer people were "farmed out" to others, and as a result the craft were exceptionally expensive to build. Bulky, heavy and cumbersome mixed flow lift fans were used, where a one or two stage axial fan, with perhaps one twentieth of the size would do a better job, and expensive aircraft propellers would be selected where a much less sophisticated propeller would do for a surface skimmer. The flexible edge, or skirt also evolved along a line that requires much complexity and surface area, and a built in ability to destroy itself even on the simplest terrain. Low cost and simplicity seemed to not be an objective.
Two hovercraft of note are the SRN 4, and the SRN 6. A few SRN 4 craft were built and put into service as vehicle and passenger ferries crossing the English Channel. Age and wearout, (and the Channel Tunnel?) have been causes for this craft to cease operations (At last word, the SRN 4 is in operation! http://www.hoverspeed.co.uk/hover/.)
Fan-Tastic I
The Fan-Tastic I sev was a 70's program that produced about a gross of 8 and 10hp Briggs engined homebuilt craft. The hull was an aircraft fabric covered wood frame over a couple of carved polystyrene floats. Propeller and fan started as fiberglass covered balsa, and then fiberglass covered foam, and finally molded Birch plywood.
Climbing a river bank on only 8hp was easy for fan-Tastic I.
The SRN 6, which of which several dozen were built, is also disappearing, with a small remnant population still operating, even though there are similarly sized and powered specialty craft, notably excursion jet boats, that continue to operate as economically successful entities.
The era of the hovercraft is not dead, however, as the professionals began copying the amateurs by using more sensible, less costly construction for ferry hovercraft, such as welded aluminum and diesel engines in the AP 1-88, and numerous efforts have been made to get the hovercraft into manufacture as a recreational vehicle, and for specialized applications such as search and rescue.
However, these hovercraft still suffered from high costs, due to their low efficiency, inherited from the older designs, and the World community still assumes the hovercraft technology to be mature. The resultant vehicles usually use high power for their size, with attendant high vehicle construction and operating costs as a result. It is not unusual to have the order of 100horsepower in a 4 place hovercraft, and unlike the case of a powerful automobile, much of the power must be used most of the time.
Sevtec has taken a new course, for this old idea. By backing up and re-evaluating the surface skimmer concept, craft have been designed and built that use only one half to one fourth the power, which results in a much smaller vehicle for a given payload and speed, and the Sevtec surface skimmers have a skirt system that requires only a fraction of the material used on hovercraft. The resultant vehicles are far cheaper to build and operate, and as a bonus are more reliable and much quieter than hovercraft. An older term is taken for these craft, the SEV, or sev.
I do not consider the Sevtec technology to be mature. In a world where if your product is just a few percent better than competing products, it will eventually win the market, Sevtec technology cuts 50 to 75 percent off costs. However, as in any new technology, advances will occur through time, as economic commitment increases. Research in this area would be an ideal project for a university program,where costs are low, and where advances could be made while preserving the skills involved in working in hydrodynamics and low speed aerodynamics.
Welcome to this new concept with an old name, the sev. Join the adventure!
Bryan Phillips operating the north to Alaska Explorer that he built from Barry's designs. Very exciting!!
Here is a picture of Barry the wizard working behind the sceens. Are those pond skimmer plans I see over his shoulder? Whats that Barry's saying? Audio
This picture was shot during the expoloration in the Explorer to further the growth exponetially of Explorers. Say that three times fast!!
An information package is available for $8 U. S. that describes all of the craft, and is loaded with pictures and drawings, and an $8 price reduction coupon good on any Sevtec product. (Only slightly more detailed information on the craft is in the information package than is available in this web site.) (Mail check or Money order to the address below. State of WA residents add $.66 sales tax. For those who have a credit card account payment for the info package or any other Sevtec product may be made through PayPal, payable to Sevtec@aol.com.
The information package will be sent free to anyone purchasing plans or videos or parts from this order form or parts order form (Print out the order form using your browser or save the order form as a text file, and fill it out off line) to order videos or plans or parts right off these pages. If the order form cannot be printed out, state that the order for videos or plans is off this web site and the information package will be sent free of charge.
. SEVTEC . PO BOX 846 . MONROE WA . 98272 . ph:360 794 7505
Website email watercatwn6535nd@yahoo.com I post a lot of picts. Some I take, some I take from you. I always try to give every one credit. Try not to wine about it. But if it bothers you let me know. I'm just trying to have fun and promote my hobbies. More than likely it helps promote you!!
