Ekranoplans and ground effect

Nice definitions aztec!................................. but some of them are
wrong!
The WIG vessel is a aircraft at the moment it leaves the surface. And so it is seen internationally by authorities.
The statement:
>>>>>>>>>>the landing area is always directly below you.<<<<<<<<<<
is the sheer nonsense, as everybody understands easily.

Nevertheless you are working on a very interesting and demanding project, no matter how you call it.
Good luck!
Richard

 

In it's Code of Federal Regulations FAA defines "aircraft" as "a device that is used or intended to be used for flight in the air".
It also defines "airplane" as "an engine-driven fixed-wing aircraft heavier than air, that is supported in flight by the dynamic reaction of the air against its wings".
So it is quite clear that a WIG is legally considered to be, in a general sense, an aircraft and, in a more strict sense, an airplane. Not a boat.

But like Apex said (well, kind of) - who cares? They are very interesting machines anyways.

 

Except that there is explicit mention of WIG craft in the FAA regs, and they specifically say that they don't want to hear about anything which cannot by design exceed 50 feet above ground level.

I was under the impression that this was a restatement of global regulations, but evidently not. I was lulled into a false sense of security by maritime law.

The license is a marine license. My hovercraft can be converted to a WIG. It's a really crude and inefficient one, but a WIG just as well. It can get to about 6 feet above the surface. It gets the same boat license that a regular hovercraft or regular boat does.

Edit: Here is a link with the most brief and understandable outline.
http://addington-barker.com/wing_in_ground_effects.php

Search on "license" in the page.

 

In Europe you need a pilot license (aircraft).

But should´nt we focus on the project of our young member? He does´nt need any licence.
Regards
Richard

 

That's wrong info. European directives do not require aircraft piloting lisence for wigs, as they are boats. Laws can be different in each european country though, but certainly not all of them requires aircraft licenses for wigs, if any of them does it's quite surprising as most if not all have ratified IMO conventions as well as FAA conventions and wigs are dealt with by IMO.

Colregs are clear that most type of wigs are boats, not aircrafts.
http://www.imo.org/Conventions/contents.asp?doc_id=649&topic_id=257

 

Yes WIG is most definitely an aeronautical subject. A complex and fascinating one, but not a boat when being operated.

 

Technically somewhat yes, legally definately not so.
International IMO convention ratified by most countrys are clear wigs are boats/ships. Check the colregs, they don't say anything about aircrafts but do about wigs !

When wigs turn air rudders can turn their heading, but not their course over ground (or water) !!! A centripetal force is needed for that and it must come from engines or by contact with water.

 

A WIG is an AIRPLANE and you need a pilot license to operate. As for a seaplane which is mentioned in COLREG too.

I took part in some testruns of a WIG in the early 70´s assisted by Dornier on the Bodensee lake, and we had to have a pilot license. And there is a good reason why, almost all WIG craft can leave the ground effect.
And naturally a WIG can change course by turning the air rudder, although some are a bit indolent like a hovercraft.

But again: I think we are going to hijack a thread, and we should be polite and focus on a boys endeavour.

Regards
Richard

 

In effect, the Title 33 of the US Electronic Code of Federal Regulations ( http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&tpl=/index.tpl ) talks about WIGs, in this paragraph:
"Vessel means every description of watercraft, including non-displacement craft e.g., wing-in-ground (WIG) craft, seaplanes) capable of being used, as a means of transportation on or through the water."

Yet, the Title 14 of the same Code gives a definition of an airplane which says (as I said in my previous post):
"Airplane means an engine-driven fixed-wing aircraft heavier than air, that is supported in flight by the dynamic reaction of the air against its wings"

It doesn't discriminate various flight levels and I couldn't find any reference to 50 ft minimum flight altitude, so the two definitions above appear to be in conflict with each other.

Apart from that, I have another question, coming from logical reasoning.
How on earth can WIG be classified as a boat if we all know that it's principal characteristics is the capability of flying in ground effect, entirely detached from the surface and completely sustained by aerodynamic forces? Is it because it has a takeoff phase, during which it is immersed in water?
And what if a WIG is made to operate inland, taking off and landing on a conventional airfield, with no floating hull? It is still a WIG but is it a boat?
Is then a seaplane a boat?

 

Having just searched for it, I can't find it either.

I know I read it somewhere. I'm asking around now for people who can tell me where that information came from.

However, by the logic used above any hovercraft or air prop driven tunnel hull would also no longer be a boat, and therefore would not fall under marine law when in operation in that mode.

I do know for a fact that that logic in my previous paragraph is legally false in the USA. When on water, I follow USCG rules. When on land, I am subject to the laws of off-road vehicles for the area I'm in, or hovercraft rules if there are any. In other words, I am bound by the rules which most closely resemble the mode of travel I am using at the time.

An aircraft is legally bound to pass no lower than 1500 feet above any populated area, including waterways. A WIG cannot get to those altitudes, therefore is automatically breaking the law every time you use it, if it is an airplane.

However, it ALWAYS interferes with boat traffic. Even if it is technically not touching water, they do not fly over other boats and other boats must take them into account for navigational purposes.

The guys I know who use them slow down for no wake zones and follow all other maritime laws as they apply to the situation. Unfortunately I don't have the links, since I'm not going to be flying a WIG any time soon. I my convert my hovercraft later, but it's not in the cards right now.

Thanks.

 

Don't have anything on the FAA part yet, but here's the marine version:

http://www.navcen.uscg.gov/mwv/navrules/navrules2003.htm

Search on "WIG craft" for all pertinent text.

Particularly,

The way I read this, 18 (f) (ii) states that while the craft is on or near the surface, it needs to follow boat rules. Most WIG craft can't be operated out of ground effect, or if they can they can't maintain flight out of ground effect. If you are in such a vehicle, then by the maritime law as stated above, you need a marine license and need to follow the rules of the road for boats.

If you CAN fly outside ground effect, then a pilot's license is obviously necessary.

 

INTERIM GUIDELINES FOR WING-IN-GROUND (WIG) CRAFT
http://www.imo.org/includes/blastDataOnly....3D6713/1054.pdf

which has Annex 2, Form of Permit to Operate WIG Craft on page 144 of the printed document, which is 146 on the PDF.

That is basically an application for a license.

By implication, the existence of the above document and the Annex 2 part means any type A or B WIG can be licensed as a marine vessel and nothing else.

 

Interesting..............................
is all I can say.

 

OK, guys which is biggest WIG to ever Fly?

Howard Hughes Spruce Goose. Yet it was a WIG. Never flow out it. A WIG is an Airplane or Seaplane that is limited in its lift to only FLY in Ground Effect, which is a cushion of air generate under wing. It is aided by the turbulence at the wing tips and therefore has much greater lift.

Guess what, they have shorter wings and smaller engines than a regular plane therefore the supposed savings in fuel.

But think of this, a Plane is in its most dangerous mode on landing or takeoff. Flying a few feet above the waves is very dangerous and hard to do. That is why no one has been successful at putting a wig into commercial applications. No one has yet designed a 100% stable passive WIG wing. No one has yet built a fast reacting, sonar driven, computerised water hugging electronic flight control system. Flying at 100 feet is a challenge for long distances, imaging crossing an Ocean at 30 or 40 feet.

 

Mydauphin,

Some of what you are saying is incorrect.

The Spruce Goose was not designed to only fly within ground effect. The fact that it never got over 70 feet was more of a political decision than a technical failure.

The thing which makes a WIG into a WIG is wing loading. A short, stubby wing with very long chord is a good thing in a WIG, and a bad thing in an airplane. Once you start to escape ground effect, the wing losses cause the WIG to descend again.

There is a lot of very good, interesting reading on http://www.se-technology.com about what a good WIG is all about, and why it can reasonably fly in ground effect when it's dangerous to fly a regular plane in that space. They can say it much better and more concisely than I ever could, and that's where I learned it anyway.

I have mentioned my UH-18sp hovercraft before, which can be easily converted into a UH-18spw wing in ground effect. I want to contrast this device with a purpose-built WIG.

A purpose-built WIG is designed to take off at a relatively low speed and then accelerate to a much faster speed while never being able to stay out of ground effect, and to do so very economically. Take-off power is generally a lot higher than cruising power.

On the other hand, a UH-18spw is NOT a purpose-built WIG. It is a hovercraft to which you can attach a wing and fly around in ground effect. It is less efficient as a WIG than it is as a hovercraft, which according to the se-technology guys is wrong. The UH-18spw takes off at around 55 mph and then cruises at 60 or so. It holds less payload in WIG mode, has less range and it flies in a much nose-up attitude. All of that seriously irritates any WIG purist.

A UH-18spw can't fly out of ground effect for long even if it has power, because its wings have no dihedral and there is no aileron to prevent it from rolling over. When in ground effect, the nature of ground effect gives more lift to the lower wing and so it is self-righting. When built per plan, they don't have power to escape ground effect for long. They would be a class B WIG by that definition.

There are two groups of WIG people: The academic purists, who hang out on se-technology and the associated forum, and there are the practical WIG people, who just want to go out and fly. The purists have regular arguments about whether a UH-18spw is really a WIG or not because the speed and efficiency do not match the WIG expectations. However, the main critical property of a WIG is there, so in my book it's a real WIG even if it's not a very good one.

The se-technology guys keep insisting that there are no WIGs you can get in the private sector, even though the UH-18spw was listed last time I checked and I know several people who have the WIG version working.

Finally, back to the last point of argument with your post.

IMO, the reason that there are no commercially viable WIGs in use is not because of a lack of stability. That may or may not be there, it's a topic of discussion on the se-technology forum. The real reason though, is that whatever you can load onto a WIG and carry can easily be loaded into a 747 and flown there faster, safer and more reliably. And for less money. Per ton mile, a 747 is more efficient than any WIG which has ever been constructed. They get there by flying high and fast, rather than low and fast. There are no boats or birds or anything to hit, so it's safe. They go in a straight line, so it's fast. They land at airports, so the normal shipping trucks already go there.