The Ship Model Forum

There's a programme on the BBC tomorrow night about the Ekranoplan - more details here and some footage pf the Caspian Sea Monster: http://news.bbc.co.uk/1/hi/magazine/7638659.stm

John

A perfect solution, even approved by Shakespeare: "Kill all the lawyers."

Ever get the idea Shakespeare was not entirely happy with the administrative aspects of his life as a theatrical producer?

If its a ship its subject to SOLAS 2010. Its safety rules will have been written by more lawyers than you can possibly imagine....and its much stricter than the rules for those highly subsidized and unsafe tubular extrusions 5 miles up.

Les, even though the air is dense, ground effect decreases drag by increasing lift dramatically for a given amount of wing area... thus you need less wing, which means less drag.

Personally, I see the WIG craft as being stuck in an area that's not profitable. Surface is slower, but it's cheaper than air. WIGs are faster than surface, but slower than pure air transport. I don't think there's a viable "middle ground" market that would accept the route and seasonal limitations WIGs would have. I could see them a fast intercoastal/large sea ferries, but not as serious long-haul cargo.

Looks strangely familiar the Boeing Pelican prototype!!! Resembles in some way Howard Hughes Spruce Goose!!!

A question and a scenario at this point:

An (any?) Ekranoplan flies in ground effects at an altitude of 50' or less. In a calm or mild sea state this should in itself present no problem (except for the high speed, which is another matter). I would assume that 50' would remain fairly constant regardless of sea state, in order for the ground effect to work.

What happens in a rougher sea state? How about big rollers way out in mid ocean? What happens after an Ekranoplan, cruising along at, say 400kts slams into the side of a ship it can't see on radar because the ship is in the trough of one of those big rollers?

What happens when the supply of barf bags runs out after following said rollers for hours at sea?

The Ekranoplan sounds to me like a lawyers dream. How about it, Richter?

The point of developing an aircaft is to increase economy/payload. Flying in ground/surface effect very efficent as far as lift and fuel burn are concerned. Of course Boeings project is probably a pipe dream; I first read about it at the Paris Air Show four or five years ago.

Scott

Heres more:

Proposed Huge Boeing Pelican Aircraft
Its payload would be more than an order of magnitude greater than that of a C-5 Galaxy.

This article has comparisons to other existing aircraft as well:

The Boeing Co.'s proposed Pelican transport aircraft would dwarf the largest plane now flying, the Russian-built Antonov An225.

The An225 has a 290-foot wingspan, which would be more than 200 feet shorter than the Pelican's preliminary wingspan design of 500 feet. It is 275 feet long, compared to the Pelican's projected length of more than 300 feet. And its cargo-hauling capacity, 275.5 tons, would be only a fraction of the Pelican's as-designed 1,400-ton payload.

The Daily Telegraph has an artist's rendering here.

The Pelican will be designed to fly 50 feet above the ocean, using the buoyant aerodynamic effect of flying close to the water to provide its maximum economic range.

The BBC says Boeing hasn't yet committed to building it.

Here's the best article on the prospects for the Pelican.

Update: Some additional clarification from the Pelican Program Manager.

Other than cruising at low altitude above water, the Pelican has little in common with historical Russian wing-in-ground-effect (WIG) aircraft. The Russian WIGs were designed primarily for short range, sea-based military missions. With beefy structure and ample propulsion systems for water operations, they were no more efficient than modern subsonic transports, despite their lower speed.

The advent of computer-based flight controls permits the Pelican to be land-based, so that it can be much lighter and aerodynamically cleaner than earlier WIGs. It appears, remarkably, that land-based WIGs differ little from aircraft optimized for conventional cruising altitudes. This permits a dual-mode aircraft to provide substantial operational benefits in the long-range transport of cargo.

Advanced flight control systems also provide ample maneuverability while automatically maintaining safe clearance from the water.

— Blaine K. Rawdon, Pelican Program Manager, San Pedro, Calif.

Pelican would fly on a cushion of air.

Riding on top of a cushion of air, the Pelican would experience 70 percent less drag than a normal plane, allowing it to travel further while using the same amount of fuel. The wing-in-ground effect occurs at an altitude equivalent to 10 percent to 25 percent of the wing’s width at the point where it joins the fuselage. The phenomenon increases the ratio of lift to drag for a wing.

"It’s an effect that provides extraordinary range and efficiency," says John Skorupa, senior manager of strategic development for Boeing Advanced Airlift and Tankers. "With a payload of 1.5 million pounds, the Pelican could fly 10,000 nautical miles over water and 6,500 nautical miles over land.

Boeing has been looking at it for some time.

Look here: http://www.boeing.com/news/frontiers/ar ... /i_pw.html

An Ekranoplan would be moving through the densest air on the planet, and would have to be under power at all times to avoid dropping onto the water. This is why I would expect fuel ecomony to be poor.

The only way an Ekranoplan would be exempt from the navigation rules would be if it operated high enough off the water not to pose a navigation hazard to other vessels. If that were possible, it would no longer work in ground effect and would be just another airplane.

http://www.modelwarships.com/reviews/sh ... 0_1068.jpg

Jim B's lovely little rendition.

The Russians flew a 550 ton ekranoplan in the 1960s. That remain the heaviest aircraft of all time, beating the An-224 by a significant margin. BTW, I notice the Wikipedia article claim the 550 ton Russian ekranoplan to be capable of carrying 1000 tons. For a 550 ton airframe, even one running on ground effect, to carry twice its own weight in cargo is something I find hard to believe.

Looking at the Wiki entry- I know, I know, never trust wiki completely- it seems there were problems with controlling the Ekranoplan, requiring automated systems and advanced technology- more advanced than Soviet-era at least.

The article alludes that research is ongoing.

Ekranoplan?

I doubt a commercial ekranoplan would be more energy intensive than a commercial passenger jet carrying the same weight and providing the same passenger and cargo space. By taking advantage of ground effect, an ekranoplan requires much less direct aerodynamic lift to stay aloft than a outright aeroplane. With any lift generating shape the amount of lift generated and the amount of drag induced is positively correlated. So an ekranoplan can also have lower drag than a commercial airliner of comparable weight an capacity, thus the reduce energy intensity and increased fuel savings.

If the commercial benefit of an ekranoplan is compelling, then I am certain exemptions from unsuitable navigation rules can be obtained to enable the ekranoplan to operate.

A commercial Ekranoplan would probably be more energy-intensive than anything short of the space shuttle. Under the International Navigation Rules, the thing would be classed as a ground-effects craft, subject to the same rules of navigation as any other seagoing vessel. Might be hard to be the give-way vessel at 300mph.

What kind of seas can these things take?

Seems to me such a thing would be a juicy target- high infrared, radar, and visual signatures.

747's can cross mountains- these can't.

Why is ekranoplan so out of favor that nobody I know of is seriously developing it? It sounds to me like for a company like Fedex, an ekranoplan would be much more cost effective than flying B747s over the oceans. Also ekranoplans should be much more effective than missile boats, yet lots of people are working on newer missile boats, and no one seem to be working on an ekranoplan missile boat.