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Thread: 250 lbs. wig one man, river, lake, toy?

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    Registered User gahan's Avatar
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    250 lbs. wig one man, river, lake, toy?

    afternoon all! Iv'e been surfing in areas that to date ,I've not investigated. Wig aircraft , orion has a very complete overview of the potential to carry weight does anyone think their could be a market for this type of craft ? kit through one of the existing suppliers like Izon,fisher, lohel ? this is for us duffers that love to build but would prefer to stay at flare on final, it would keep the you're going to kill your self extended family backed off, and if you have lots of flat water it could be a major good time, can't loan out "just to techy" let them trash the jet ski. Are the little airplane boys missing something, like a market

    reguards tom Gahan

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    Super Moderator orion's Avatar
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    Dozens of organizations all over the world have investigated the application of WIGs to recreational and commercial applications and most have concluded that yes, there is a potential market. The difficulty however comes in several categories:

    One, the WIG craft is a very critical design exercise and has to be done just right to meet the specific requirements of performance and stability. This however is complicated as there is very little publically available information (not much in private hands either) as to the design specifics of winged ground effect vehicles (airplane design data is only slightly applicable) and so, any company looking to get into this field will either have to invest in developing their own database or, be willing to risk their customers' lives on an unproven product. This second option sounds highly unlikely but it is surprising how many organizations actually go that route - fortunately most have gone out of business, usually after a spectacular crash.

    Two, the WIG craft is rather unique in its configuration and as such, generally requires specific facilities for its operation. Simply said, due to the design constraints you cannot simply pull one of these to a normal dock. You will need some specially designed docking and mooring facilities and equipment (or ground in on shore) in order to get some level of conveniance.

    Three, the WIG craft is crtitical in its design constraints, something that might prove somewhat dangerous for the average homebuilder since building it even slightly out of balance or trim will almost certainly cause it to end up upside down somewhere. And yes, it's much more critical from this standpoint than an airplane. And no, you cannot simply add more power since that may enable to craft to get out of ground effect, which results in dramatic destabilizing shifts in the wing's pressure distribution and thus the craft's trim.

    The Russians have been playing with these for decades but despite all their work, virtually every model they built has crashed, usually killing all on board. The remaining models are all now in mothballs. It used to be said (usually by the Russians) that the Russians are the world's leading experts in WIG design - however practical examples have shown that that is about the same as Ford saying that they are experts at building Edsels: In other words, it doesn't mean much.

    In short, yes this is a potential market but one that requires a substantial investment to do it right. There are one or two organizations working on recreational versions (there's a modified hovercraft being marketed currently for instance) but these are trial and error designs that in my opinion are accidents waiting to happen.

    The more responsible organizations, several of which are in Europe, have been working this problem for decades but a few years ago there was a fly-off and of the six or seven craft entered, none was able to leave the water due to a slight chop generated by a less than ten knot breeze.

    Simply said, yes there is potential but in my opinion, don't hold your breath.
    "To live is to learn; to learn is to live" (author unknown)

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    Registered User gahan's Avatar
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    Talking I knew that!

    Thanks for the promt responce. but lets get really down and dirty. Last spring a company mfg. a water toy that flew behind your speed boat It was about $500 .my buddy who runs the marina ordered 3 sold out one weekend. one week later the mfg wanted them all back. It seems if it will scoot above the water at 2 feet with 25 ' of rope lets add 200' and zoom to 30 ' and promtly kill your dumb A#%^. I tried it it was a hoot It would have to look like a three man lawn chair and let E mail sell it.

    Merry Christmas
    Tom Gahan

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    I have two uncles that had a hovercraft business (they are now retired). They designed and built their own hovercrafts and were quite successful. They experimented with a WIG design. Theirs worked quite well, but was not as easy to fly as a hovercraft. It also needed more room to manuever, so they scrapped the idea. They never did sell the design because theirs could be very dangerous in the hands of an inexperienced pilot. It could break ground effect, but if it did, it would lose speed quickly and stall.

    Here's a few pictures of theirs.

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    Registered User gahan's Avatar
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    wig toys

    thats's slick
    It looks like they were having a ball. what about a rudder in the water up frount. with a little hydrofoil to pull the nose down if the canard is fixed? I'm thinking 6.5 to 7' wide to fit in garge low aspect ratio?
    Reguards
    tom gahan

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    There's an aussie company (can't remember the name at the moment) that makes a passenger one. It seats about 18 people iirc and last i heard was being marketed towards border patrol and island to island taxi in QLD


    Found it.
    Unfortunately it doesn't appear to be Australian anymore

    http://www.flightship.info/head.htm
    Last edited by smenkhare; January 8th, 2007 at 12:56 AM.

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    Super Moderator orion's Avatar
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    The first Flightship craft was an eight place, with an nineteen place reprtedly in the works. The whole project was funded from Malasia and developed jointly with Dr. Fischer of Germany. Unfortunately though, while in the certification process, the controlling company discovered a few questionalbe financial dealings by the Aussie partners and thus ended up pulling the plug, moving the project up to Malasia. There have been several publicly released news tidbits that suggested a new partnership for a restart but as far as I know, nothing concrete. Their web site now suggests that the project is in Turkey but I don't think that site has changed in quite some time.

    The hovercraft/WIG combination mentioned by BearHawk747 was an interesting approach but the intracasies of WIG flight would have made it an accident waiting to happen. A further complication would have been the fact that Dr. Fischer actually patented the idea so if they ever got beyond the prototype, there might have been a chance of a lawsuit.
    "To live is to learn; to learn is to live" (author unknown)

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    Re: 250 lbs. wig one man, river, lake, toy?

    Intracasies of WIG flight? Both of my uncles are experienced aircraft pilots, I don't see how a WIG would be any more intricate than an airplane.

    I'm also trying to see how their design would infringe on Dr Fischer's patent. Did he patent flight in ground effect? If so, every plane would infringe on his patent when they flaired to land.

    If the patent applies to his craft, I don't see how a single engine two person WIG is the same as a 19 passenger twin engine craft.

    I'm not saying that you are wrong, I just need some clarification on this.

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    Super Moderator orion's Avatar
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    Re: 250 lbs. wig one man, river, lake, toy?

    This actually calls for an answer longer than this medium would allow - but I'll try to keep it short and still meaningful. First, WIG flight as defined for the purpose of designing and building an actual WIG craft is defined as height off the ground as a function of span and as a function of chord length. Given the constraints necessary to take advantage of WIG operation, the wing has to be lower to the ground than that of even the lowest of low wing airplanes (unless of course they land gear up). A common design point is an "h/c" of about .1. As such, a conventional aircraft would have a hard time being a WIG vehicle just simply due to its wing geometry, plus given a typical GA airplane, it would be virtually impossible to safely fly only about 4" off the surface.

    Even large aircraft like the 747 do not see actual WIG flight, even though they do have large chords. Due to the dihedral and wing taper, more than half of the wing is out of the chord based ground effect regime.

    In this realm of flight several things happen. The first and major that deals with trim and controllability is the fact that in level flight in close ground effect the resultant Cp vector of the wing shifts aft to about the 50% MAC point (in free air it is of course at at about c/4). So, if you trim for ground effect then accidentally pop up higher, possibly into free air, the Cp moves dramatically forward and you may end up with an unstable airplane.

    Given this behavior, coupled with the dynamic effects of ground effect craft, you end up with trim requirements that are dramatically more complex, and sometimes counter-intuitive, than what you require in a conventional airplane. The stability equation for instance, is applicable only for a particular height - you move up or down a couple of inches and you have a different condition you now have to solve for.

    In short, this is why designing for WIG flight is very difficult and requires very specialized knowledge. Due to IMO regulations (International Maritime Organization - true WIGs are classified as boats - no FAA to deal with), true WIGs (Class A and B) are designed to operate only in ground effect. The design of a Class A WIG has to have inherent features that actually prevent the craft from reaching free air. Class B is the same as Class A but it can have "brief" pop-up capabilities that would enable the craft to make short hops out of ground effect for obstacle avoidance or possibly, ground based landing.

    Class C allows for extended free air operation but that essentially becomes an airplane and is no longer under maritime jurisdiction (back to the FAA).

    The inherent design features of WIG craft are essentially counter to what we need in conventional airplanes. Two of these are low aspect ratio wings and a bit of anhedral - both of which would make for poor and even uncontrollable airplanes. There are of course other approaches, as demonstrated by some of the Russian and Chinese Ekranoplans, but in their environment, they all pretty much have to operate within the confines of the same physics.

    Regarding the patents, no they did not cover ground effect flight, but they do tend to cover those aspects of the technology and configuration that make the craft operate better at the extreme low altitudes. The two primary technology innovators were Dr Lippish and more recently, Dr, Hanno Fischer. The Russians have also been prolific in the directions they pursued however most of their work has been directed more by politics than actual technological pursuit and as such, is generally dismissed by Western ventures.

    In most developments, one of the keys to a sucessful WIG is of course the inability to accidently or purposefully pop up into free air. As such, the designers tend to heavily optimize the wing area-to-power-to-weight relationships. The result of this is that most WIG craft tend to be somewhat underpowered (as compared to conventional aircraft). They are however marine vehicles, which of course have to accelerate and come up on plane prior to take-off. Due to the design issues of hull borne operations, anything that one can do to reduce the effect of the bow wave and the subsequent planing drag is of extremem benfit to WIG design. And so here we come to the patents.


    First, the patents are technological in nature and as such, the size of craft is irrelevant. One of these that applies specifically to the previous discussion, is specifically the combination of a WIG craft with an air cushion configuration, which is internationally owned by Dr. Fischer and his company. I believe the patent was general in nature so the configuration of the cushion is irrelevant. Below is the Fischer Flugmechanik Hoverwing in flight. The air cushion is developed between the two hulls. There are retractable doors at the fore and aft locations that create the cushion cavity. In flight they are retracted into the belly (this also results in interesting trim changes).


    Last edited by orion; January 17th, 2007 at 05:47 PM.
    "To live is to learn; to learn is to live" (author unknown)

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