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Wing In Ground Effect Craft Design

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Gewher

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Jun 28, 2016
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Jerusalem, Israel
I would like to discuss the different aerodynamic designs of wig craft. Any insight or information would be greatly appreciated. To get the conversation started I am interested in a longer range craft powered by twin engines, either Chevrolet motors or aircraft motors. A craft that is similar to Airfish8 or Aron 7 and the new design from Aron the MK200. Where do you start on testing different designs aerodynamic properties? Right now I'm just going to start by trial and error which will become expensive rather quickly.
 

Topaz

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Welcome to the forums!

There are already several very good threads on this subject. Use the advanced search function with "WIG" as the keyword and the search limited to "topics", and you should find them all. A discussion of all existing or "different" WIG designs, and a full discussion of aero design for WIG craft is beyond the scope of this forum. If, after you've reviewed the material already here, you have specific, narrowly-focused questions, please feel free to ask them.
 

Himat

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WIG (Wing In Ground Effect vehicles), Ekranoplan, dynamic air cushion vehicles. Vehicles to achieve efficient high speed transport at sea and light airplanes within boat regulations. Unfortunately there are a few catches.

The large scale high speed sea transport has never materialized, one reason can be that the sought efficiency have never been realised and the cost have been to high. On the technical side, the required takeoff power being several times the cruise power for designs to date has been one culprit.

The boat regulation “light aircraft” stumble on physics Ekranoplanes do not scale well. To clear waves of any significant height the vehicle is out of ground effect. It is then by law in most countries an airplane. From the design perspective, the transition between in ground effect and out of ground effect is challenging as the stability requirements differ substantially.

Present a little more on your idea and you may get the discussion going. If you have not already done it search this site for:
WIG
Ekranoplan

And you get a lot to read, some of the threads I do think had links to useful information on the internet.
 

kent Ashton

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I am interested in a longer range craft powered by twin engines, either Chevrolet motors or aircraft motors.
Hummm, just thinking about this:
- You are building a boat-airplane and like the flying cars, the compromise is often not very satisfactory.
- You probably will have to fly it mostly over water.
- Near the coast there will be lots of sea birds to ruin your day.
- The seas will kick up salt spray that will fog your windscreen and corrode your engines.
- Your "long-range" will be much less(?) than the range of a comparable aircraft because engines use a lot more fuel at low altitude.
- There is no forgiveness of carelessness in ground effect. At the speeds you suggest, a small mistake and you're dead.
- If you encounter weather on your long-range trip, you have the problem of flying in clouds and rain a few feet above the sea and the shipping lanes with no radar help.
- You will never get an IFR (instrument flight rule) clearance because you can't get them at your altitude so you are on your own.

Set your goal a little lower--a small one that you can play with. :)
-Kent
 

HoneyMoneyToo

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Jan 19, 2016
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Georgia, USA
I don't see where it's such a hard task as long as you stay off the open ocean and out of 20 ft seas. Salt water is real corrosive as everyone knows but boats are in the water, jet skis are in the water, sea planes are in the water. As long as you take precautions to protect them as much as possible and keep them clean and washed down as you should then you should have any short term problems but yes long (years and years down the road) term no matter what u do it will eventually break down. The new marine 7 557 outboard is based on a 6.2LS motor from GM, what's the difference in following their "standards" for marinization? Keep engines covered inside with air cooled radiator on outside, shaft with thrust bearing to outside for the prop. Very plausible in my opinion.

The airfish 8 used a 400 hp car motor to push 2 props, why not have 2 motors to push 2 props then you have redundancy if you are in flight, you couldn't get off the water with one but who care u wouldn't be way off shore and need help you would still be at the dock.

Boats have radars, why couldn't you hook one up on this craft? Use large monitors (for a boat) and a co pilot/captain maybe even FLIR to see at night? Yea it just got expensive but nobody mentioned a budget... And keep your A$$ out the fog and storms, watch the weather and your radar to know when to not go or go around it. You don't go offshore fishing with 6ft seas and thunderstorm out there do you? I know I don't.

Kent Ashton- cozy and a long Ez... I like it! I want a velocity rg!
 

kent Ashton

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Boats have radars, why couldn't you hook one up on this craft? Use large monitors (for a boat) and a co pilot/captain maybe even FLIR to see at night? Yea it just got expensive but nobody mentioned a budget... And keep your A$$ out the fog and storms, watch the weather and your radar to know when to not go or go around it. You don't go offshore fishing with 6ft seas and thunderstorm out there do you? I know I don't.
Ha! What is this FLIR, radar, thrust bearing-equipped multi-engine boat-airplane going to weigh!? Or cost? $1Mil? $2Mil?

Let us return to Earth, my friend, my nose is bleeding. :)
 

HoneyMoneyToo

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Haha, the original post said nothing about size, weight, power, or cost constraints. Almunium LS engines are cheap, dime a dozen as are over time air cooled engines, boat radar is realitivy cheap but the FLIR is about my yearly wages ... If you were to do it right to cross small areas such as the gulf or down the coast or "island hoping" you would need redundancy in engines and every critical system. Thrust bearings are in planes and they are light enough to fly, how much weight do you think one would be to add to one of these, 20 pounds tops? if you didn't add one it would eventually "push the crank out" so to speak.
747 weighs 700-800,000 pounds? Flys 30,000 feet for 6,000 miles? You can make anything fly, in this case if you have couple 100 million laying around just depends on that $$$$
 

Gewher

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The third pic I posted is out of the Aron camp with the model they are calling MK200. This is in the neighborhood of the craft I am proposing to build, of course I intend on starting with a smaller prototype similar to Aron 7 which could be hauled on a trailer as pictured with a single engine and single prop. I may be a little naive at this point in my life, but I do not really see what the big deal is with constructing such a craft? Of course it will take time and a boat load of cash, but how much is too much when you are talking about your life masterpiece? Does anyone have a computer program on which you could build a model, test model with environmental factors to get figures for horsepower needed to takeoff and fuel ranges? Thanks!
 
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kent Ashton

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I may be a little naive at this point in my life,
I read a couple of Google page results on the Aron-7 and don't see where they have sold any.

As a hobby, people do impractical things. Nothing wrong with that. You can learn a lot from the exercise. But your idea IS impractical as you've proposed it: way too complex.

I knew an older gentleman here in Charlotte who had worked for one of the big aircraft manufacturers and his idea was to build a tilt-rotor aircraft. He actually built the one in the pics from scratch. He spent years and thousands of hours getting to this stage but it never flew. It cannot fly. Too complex, too heavy, no engine he could afford. He eventually realized that but it was his hobby and he worked on it until he died. The Charlotte museum made wood props for it out of plywood and aluminum flashing just to complete the picture.

Boeing can build a V-22 tilt rotor and make it work. The U.S. Marines can afford to operate it. THEY could build and operate a multi-engine long-range WIG.

Yes, I'd agree you're a touch naive, my friend. :)
 

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Victor Bravo

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I'm guessing that as you scale a WIG down from a larger Ekranoplan size, the wingspan and chord have to be relatively larger and larger in proportion to the fuselage/weight/power. You can shrink everything down except the swells and waves in the water. "Ground effect" is a function of span and chord I believe, and I suspect that the limitation is the proportion between the size of the waves and the span/chord/aspect/whatever. So even taking Reynolds numbers and "Scale effect" out of the equation... a 6 foot R/C model Ekranoplan cannot possibly hope to successfully fly as a WIG over the ocean or even most lakes.

Well, El Mirage lake might be an exception :)
 

Gewher

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Jun 28, 2016
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Jerusalem, Israel
First, let me say that the tilt rotor craft looks pretty good. Sucks that it can't fly, however it does look a bit complicated with the tilt motors. I assume everyone is aware of the airfish 8 videos on YouTube. I may not know basic strategy but I have been doing some research on the matter for a little while. From what I can tell the airfish is able to ride over water, light chop, and even sandbars without any loss of control or affecting ride height dramatically. I'm disappointed that the airfish operation has disappeared from what I've seen. I really thought it would of caught on more than it did. The Aron company seems to be still manufacturing wig craft as to my knowledge. The old man in Charlotte had a dream and he followed it, so good for him.

Airfish 8
https://youtu.be/TYFEFekPzDM
 

Himat

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First a comment about the Aron. They state on their website, THE FLYING SHIP ARON that their vehicle is a class B WIG. Looking at the picture of the prototype in flight there is some pictures of the vehicle obviously flying like an airplane well out of ground effect. A class B WIG do have this capability, at least lightly loaded, but that make the regulatory bodies in many countries regard them as airplanes.

Next, a tip if searching for information on the internet. Look at who site belong to and the format of the text. An *.EDU site with an *.PDF document often provide more scientific information on the topic.

Like these:
http://www.nt.ntnu.no/users/skoge/prost/proceedings/ifac2014/media/files/1832.pdf
http://www.shipstab.org/files/Proceedings/ISSW/ISSW_2014_Kuala_Lumpur_Malaysia/Papers/ISSW_2014_sX-p03.pdf
http://arxiv.org/pdf/0912.3355.pdf
http://www.southampton.ac.uk/~mb4/xin_zhang/78.pdf

Ok, no *.EDU here, but NTNU is a university and there is an university in Southampton.
 

Sockmonkey

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"Ground effect" is a function of span and chord I believe, and I suspect that the limitation is the proportion between the size of the waves and the span/chord/aspect/whatever.
Sort of. You have span dominated GE and chord dominated GE depending on the aspect ratio and shape of the wing. Your classic "Hershey bar" wing would be span dominated. IIRC a higher aspect GE wing is also a bit easier for the tail to stabilize since the COP and COL can't "creep" as much as with a low aspect GE wing.
 
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