Studing WIG (Wing In Ground Effect)

Discussion in 'Boat Design' started by Geob, Nov 22, 2006.

  1. Geob
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    Geob Marine Engineer

    As soon as I began my Degree Project. My subject is the study of WIG boats.
    I have found a lot of information with regard to the aerodynamic part. In the hydrodynamic part I cannot assemble almost by no means information on the Hull designing. :confused:

    Plz if anyone know something...

    I would be glad a lot, I am shared my knowledge with you...
    I am waiting for your suggestions...
     
  2. Trevlyns
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    Trevlyns Senior Citizen/Member

  3. FAST FRED
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    FAST FRED Senior Member

    In the hydrodynamic part I cannot assemble almost by no means information on the Hull designing.

    Look at the bottom (hull)of ANY sea plane.

    FAST FRED
     
  4. yipster
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    yipster designer

  5. Geob
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    Geob Marine Engineer

    First of all thank you for your interesting!!!

    Dear Trevlyns: I know the site of se-technology ( but i must be a member...)
    The menu bar on the left I didn't see it... I take a look and i tell you

    Dear Fast Fred: Is the seaplane the same with a WIG plane??? The WIG plane must fly some meters above the level of the sea... So i believe that we must have a hull that has small resistance in air but also it helps in his smooth flow.
    That is to say I believe that hull it plays also the role of a wing. Am I right?

    Dear Yipster: Thank you for the sites! Now i check it, so i tell you if i have any prob. I saw WIGs with Deep-V hull or planning hull... But i believe that the stepped is the hull that we are looking for. What you believe about Deep-V and planning? Can i use them in a WIG craft?

    Thank you all of them...!!!
     
  6. FAST FRED
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    FAST FRED Senior Member

    That is to say I believe that hull it plays also the role of a wing. Am I right?


    In the case of a Northrop flying wing of a Burnelli of the 30's you're right.

    The hull is all simply drag on a cigar shaped aircraft , not lift..

    The WIG has been tried , mostly by the Russians and was never considered a success.

    Mostly because the air drag at sea level is far higher than at jet cruising altitudes.So fuel burn is higher than a standard cargo hauler like a 747.

    FAST FRED
     
  7. lohring
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    lohring Junior Member

    We have been building radio controlled model boats that get much of their lift from air for several years. We currently hold several straight line speed records for gasoline powered models with them. We depend on air trapped airfoils and sponsons for lift. The most significant drag is from the propeller and rudder. Similar electric motor powered models have gone over 140 mph. Pictures and video is available in the photo gallery at www.namba19.com Below is a picture of our boat.

    Lohring Miller
     

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  8. Geob
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    Geob Marine Engineer

    Fast Fred you are right! I believe that the hull must play the role of a wing, too. Russians build the ekranoplanes, a kind of WIG, but no WIG. Ekranoplanes are something like as plane that fly near the sea...

    Dear Lohring, the model that you have attach it is very interesting... Did you know where to buy one (If the price is low or logical)? I believe that a model will help me with my project.
    As i see in the net only "Fischer–Flugmechanik" have make a WIG that fly without problems! I believe that Germany has a very good technology on WIGs. And Russians, too. But in Ekranoplanes...
    Plz if you have more information about models i would like to inform me... Maybe in my project i will try to build one...
     
  9. lohring
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    lohring Junior Member

    We built this boat ourselves. It is the latest in a series of similar designs to set model boat speed records. Our inspiration was a German design for electric boats shown in the two pictures on the left. The design is very stable with the sponsons counteracting the tendency of the airfoil to pitch down. The center of lift of the wing is very close to the center of gravity and the air traps act as a very positive height control. The air traps on the sponsons reduce drag (we measured around a 3 mph speed increase at 105 mph) and are very directionally stable. Below are pictures of some of the similar designs.

    Lohring Miller
     

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  10. Geob
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    Geob Marine Engineer

    Nice work!!!
    But as I see, you use the main hull (model) as a wing, Am i right??? You don't use wings as Delta or something like this...
     
  11. Geob
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    Geob Marine Engineer

    Take a look at these photos... I want to study, and if it is possible to build one model like them... (the second photo is a model and the first is a photo of airfish)
     

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  12. lohring
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    lohring Junior Member

    The main hull is a low aspect ratio wing. With air traps it is very effective at lifting the boat. Air trapped airfoils work much better than a conventional wing for the very low altitude, smooth water boats we build. Nearly all the lift comes from the bottom of the wing so a small increase in altitude results in a large loss of lift as the air spills out of the air traps. Any attempt to lower the altitude results in a large increase in lift as the air traps seal better. This effect works on the sponsons as well. The boat is very directionally stable since most of the drag is from the rudder in back. The air trapped sponsons tend to blow a trough in the water that channels the air trap fences. Any attempt to turn the boat at speed causes these fences to hit the side of the trough and try to straighten out. The German designs do not use these air traps. They use a vertical tail for directional stability at speed and a horizontal tail in ground effect for longitudinal stability. Because they have a better power to weight ratio, they don't need the extra lift from air traps.

    Lohring Miller
     
  13. Geob
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    Geob Marine Engineer

    Thank you! Yes, the German Designs use the Vertical and horizontal tail. And they have more power in very low weight...

    May I ask you something about the hull again???

    Seaplanes use stepped Hull??? How can i find more about this. I need some Hydrodynamics because the moment that the WIG takes off, we have a very critical moment... Also we have the same problem in landing... Also before the take off, Is the WIG craft planning???

    Geob
     
  14. yipster
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    yipster designer

    [​IMG]
    they sort of invented the game, for take of the planing platform must be around CG
     

  15. Geob
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    Geob Marine Engineer

    Thanks for the photo yipster... Now i have an image how is the steps... Very usefull photo...

    You said that the planing platform must be around CG. The planing platfor in a planing mode the first part of the platform is in the air and the second planing on the sea. So, the second part generates the Lift...

    So my question is: This mode ( planing ) is changing the CG of the platform? How we find the CG in the specific operation mode?
    And one more question. Where can i find plans from stepped hulls?

    Thank you for your replies.

    Geob
     
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