Designing to fly in Ground Effect

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parkpointer

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Jan 30, 2003
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New Hampshire
I am looking for information about aircraft that fly within Ground Effects. Several years ago I was given an article about the science of flying in ground effects. The process allowed fairly heavy aircraft to fly within this envelope. Does anyone out there know of any web sites that might have information about it. Haven't found anything useful yet. Thanks in advance!:confused:
 

Captain_John

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Feb 3, 2003
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I seem to recall something that was more of a boat that most resembles what you describe.

I forget where I saw it, but I searched my cranuim for possible uses of this technology. All I could come up with was passenger ferries from Boston to Nantucket. Even then, in poor vis you wouldn't dare a trip like that. There are too many small wooden boats out there that could be in your path.

Imagine their suprise!

:gig: CJ
 

parkpointer

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Jan 30, 2003
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New Hampshire
Curiosity about Ground Effects on Flying

Yes, I believe you're right now that I recall. I drove a race boat back in the early to mid-60's that was really an experiment in an odd hull design using tunnels and cat type sponsons for flotation. The boat used a reversed single V8 engine coupled to a twin Vdrive unit through the hull which was extremely fast and somewhat controllable when airborne. I remember it had a contraption that resembled a rudder/elevator mounted on either side of the outboard portions of the transom that were adjustable with the tab-trim plates from the cockpit. These ruddervators extended out beyond the sides of the boat and sort of helped when in corners and when the boat went airborne off waves. Most boats of the day simply had a single center fairing running from the cockpit to just in front of the engine(s) and back to the transom. This boat was way to radical for its time and was penalized at most racing venues as it was faster in the corners than most of the competition. My thoughts are aimed at what happens in ground effect with regards to weight, power needed to sustain flight, limits of, and what is required to break out of and back into ground effects. I was wondering if that hull design could be incorporated into a flying boat type aircraft. As a youngster that grew up on Lake Superior back in Minnesota, I was facinated with the planes on floats and Seabee amphibians. If you have any other ideas of where to look, please reply.
 

orion

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Ground-effect vehicles have been around for some time. The Russians have been the most prolific in this technology and although most are crude, they did develop several dozen variants the largest of which, the KM (also known as the Caspian Sea Monster), was capable of flight at over one million pounds. Despite the prolific development though, the Russian designs were primarily developed as a militiary platform whose purpose was to deliver large paloads under a radar screen. As such, they were point designs, very inefficient and for the most part, dowright dangerous to operate. Today the entire fleet is mothballed.

There are a few commercial enterprises operating very small craft on several Russian rivers but due to a number of service factors, most are not likely to survive.

There has been a cyclical pattern to the interest in ground effect vehicles however no one has really stepped forward in funding a program of developemnt, especially here in the US. The International Maritime Organization (IMO) made a ruling several years ago that classified WIGs (wing-in-groundeffect craft) as "boats", something that many in the fledgling industry have applauded since it meant that any certification would be under Coast Guard rules (at least here in the US), not the FAA.

The problem with anyone developing this type of craft though, is that there is really no public information regarding the technology. There are a few papers and books (the latter mostly in Russian and not very useful), but someone has to know where exactly to search to find them.

Otherwise, anyone seriously considering developing WIG technology will basically need to create his own unique database. WIG flight however is a relatively complicated science, making the design of such a craft a very time-consuming endeavor. In order for a WIG to operate efficiently, it's wing has to be very near the surface. It has to operate within a narrow band of angle of attack and be able to maintain a relatively stable altitude and attitude.

Ground effect improves two things. As the wing nears the surface, the flight characteristics change in that first, the induced drag is virtually eliminated (drag as a function of lift), and the lift coefficient as a function of angle of attack (lift-curve slope) is increased. The induced drag reduction is a function of height versus span. The lift benefit is a function of height versus chord.

On the other hand, for wings flying at a positive angle of attack, the closer the wing gets to the ground, the higher the nose-down pitching moment it develops.

Coupling all these things together, and making the craft controllable, is a rather involved task and many believe that in order for this to be done safely, any craft operating in this range will most likely benefit by using an active flight control system. No, it's not absolutely necessary but especially for commercial operations, it may eventually be required.

The most famous work in this technology was done by Dr. Lippish, here in the US. His work was then built upon by Dr. Hanno Fischer of Germany. Dr. Fischer is currently involved with an Australian organization (Flightship) that is developing an eight seat WIG craft that is scheduled to go into commercial operation within the next year or two.

Personally, I've been working on and off in this field for over fifteen years. I was introduced to the technology when many years ago I worked with Ron Jones in his development of unlimited hydroplane designs. Since then I've been researching the technology and from time to time, consulting to other companies in evaluating their technology or helping them with the applicable design efforts.

About five years ago, my company and I have undertaken the first steps to developing our own design, called the Pelican. A small picture of the craft can be seen at our web site (www.oriontechnologies.net) under the "Marine and WIG" heading. For some basic background information, I also posted a technology overview paper, titled "WIG Matrix", within the "Papers and Articles" page.

But due to the lack of invested funds, the Pelican program is now on hold and I'm not sure if I can restart it without finding someone who is seriously interested in this type of craft.

If you have any specific questions about this type of craft I can answer, you can contact me directly.
 

Robert Young

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WIGS

Several years ago I saw a WIG being demonstrated at the Miami Boat Show. It was a nice looking craft that was obviously backed by some serious money. I believe it came out of Connecticut. At the time I was involved with marine marketing and as I had some personal interest I spoke with the operators at some length. The craft was demonstrated for the duration of the boat show and it seemed to perform quite well.

The designer told me they were looking for a method to combine a marine drive prop in conjunction with an air drive prop. The marine drive was desired for maneuvering in marinas and for initial acceleration. The craft resembled some of Dr. lippisch's designs from the 60s.

If you look at the web site for Professional Boat Builder magazine (www.proboat.com) or email them at: [email protected] you may be directed to some WIG sources.
 

orion

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The craft you're talking about was most likely the Flarecraft. Originally this was a design licensed by the US developer from Dr. Hanno Fischer of Germany. The individual however tried to make several changes to the basic design, changes that he nor anyone else on the team was qualified to evaluate. The subsequent performance of the craft was seen as quite good however, further tests proved that the flight characteritics were controllable only under very fixed and limited conditions.

The program owner indicated that the reason for the changes were to increase the payload of the given craft. According to Dr. Fischer however, the changes were made primarily in an attempt to get out of the licensing agreement (there was a pending lawsuit).

Regardless of the reason though, the changes made the craft very dangerous to operate, a fact that was evidenced soon after when the program suffered two major crashes. The first caused some injuries to the pilot, and I think the second killed him.

As far as I know, the program went bankrupt and faded away.
 
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parkpointer

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Jan 30, 2003
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New Hampshire
WIG

To Orion and Bob Young,
Thanks to both of you! I really didn't know what sort of terms referred to flying in ground effects. WIG makes sense. I am searching the web with great results.
I wish I could remember more regarding that powerboat that I drove back in the 1960's. When I was getting my pilot's license I had some opportunity to discuss what might have allowed the boat to act the way it did. I often wonder if the two people who owned the boat might have been thinking WIG. It was really neat how when the boat got air under the hull instead of having the bow go shooting right up and over, you could by trial and error ease the hydraulic rocker valve for those ruddervators and fly it back to the surface. At 60 mph and above, it was like a life saver.
I will be doing a lot of reading in the next few weeks on WIG. Thanks again! :)
 
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