WIG Craft (Wing In Ground Effect) Design in FS9

[irelectronic]

Hi all ...
I want design a Flighting boat in fs2004 or fsx
Please help on Aerodynamics and Hydrodynamics.
thanks

[Tom Goodrick]

Fligth Simulator does two things wrong that would make it difficult to design this vehicle and make it operate properly:
1. Objects that move on the surface of the water move rather strangely.
2. The aerodynamic forces in ground effect are not computed properly.

I tried to design a boat - just a simple 30 ft (10 meter) utility boat. It was powered by an invisible prop which is the only power available in FS unless you want a jet. I tried to keep it moving at low speed - 10-20 knots. It would work fine for a while and then suddenly flip into the air hundreds of feet and fall back and sink. I tried a lot of variation in where I put the float points. I gave up. But others have succeeded according to what I have heard. (I have not run any good boats.)

The water interface works well for aircraft to an extent but there are still strange things. For example try a replay of a landing of any float plane or flyiing boat. It will probably crash at the end of the replay even though it never crashed in the original landing.

The water interface is strange.

The model for ground (or water) proximity effect simply gives additional lift with a factor that changes as a function of height. The problem is that actual wind tunnel tests of the proximity effect have shown that only the induced drag is affected. It is reduced! Now any lifting theory will tell you taht increasing lift increases induced drag. In working on flight dynamics files for FS, I leave this lift effect alone just because it does give the pilot a feel for the change in flight characteristics when you get close to the ground during a landing. Unfortunametly it is the wrong feeling but it may be better than nothing which is the only alternative.

Here you see the problem for your wing-in-ground-effect aircraft. It should see reduced drag amking the motion more efficient. Instead it will see more drag with the increased lift slowing it down.

As far as I know, FSX has not improved the aerodynamics in any way.

Finally, no one has ever convinced me, as both an erodynamicist and as a boater of some experience, that a ground effect airplane has any efficieny with practical safety that makes it a good idea to pursue. I am aware of the many experiments conducted in Russia. It might make very good sence when used over frozen lakes where there are no waves. But wet lakes have a varying wave height that would cause a lot of problems with such a device. I note that many such devices have been ambitiously marketed and NONE have been put into common use.

This, of course, has nothing to do with "ground effect machines" which ride on a plenum of air pressure provided by powerful fans. Those have certain military uses but are not efficient in any sort of comparison with other vehicles. They are useful as landing craft because they do not have to stop at the water's edge.

[irelectronic]

Special Thanks Tom Goodrick.
I want to design Wig for FS9 , FSx , X-plaen or any other such simulator with carft design posibility, with clear weather and low hight wave (around 10 cm).
Can i using more than one air file (fs9 , fsx , X-plae and others) for diffrent counditions and switch them in such conditions? for example one file for 0 altitude (on water) and one for altitude between 0 to 3 meters and other for abow of 3 meter altitude.
Can i With this posibility changing the aerodynamic cofficient by factor of altitude or other parameters to meet WIG behavior on water , on surface of water and on air coditions?

[Tom Goodrick]

No.

If it can be done, it can be done with one air file and one aircraft.cfg file (which is easily edited and takes precedence over the air file.)

The biggest problem you have is that FS9 does not provide any adjustment of hydrodynamic force coefficients as it does with aerodynamic coefficients. I have looked at controlling float drag to get good performance for float planes. There are no appropriate parameters in the air file. However, I have not exhausted all permutaions of float points - number, placement and depth. It is obvious with large flying boats like the Boeing 314 that there is some hydrodynamic motion.

What is your interest here? Are you an engineer looking for an interesting field of work? The work I am aware of in past decades in this field is rather impractical. Aerodynamic effects vary with the ratio of height to wing span and the wing spans are generally short and the aspect ratios very low - less than unity. This renders the aerodynamic portion of the motion very inefficient.

If you cannot handle waves above 10 cm, you'd better quit. I don't know of any body of water worth any effort in crossing that has wave heights that low on typical days. 1 meter wave heights would be the norm on "protected" waters. But I have seen that 10 cm wave height mentioned in regard to past work in this area. That is what I mean by "impractical design efforts."

I would be tempted to try a design just for the challenge. But I can't avoid the problem of improper force calculations for ground/water height effects in FS. We could concoct a design that would appear to perform as desired but it would have no relation to reality. After all, a strong relation to reality is the heart of a dynamic simulation solution. Anything else is fantasy.

[irelectronic]

Special thanks Tom Goodrick about your useful guide
1-Can you recommend me a useful tolls or simulator for WIG simulation?
2- I read a documents that sayed X-plane can simulate Ground effect. are you grace thats claim? if thats true why i can simulate WIG craft in x-plane? aerofoil model or hydrofoil model needed?

I want design a simulated model of Wig craft and if thats ok cooperate with aerodynamist for design a real one for fun and tourism.
I am MS degree of electronic engineering.

[Tom Goodrick]

Sorry, but I know very little about the current version of X-Plane. I have an early version and know their approach to the mechanics of simulation which is very good. I know nothing about their simulation of ground effect or of hydrodynamics.

I think if you knew more about the flight dynamics involved, you would not be pursuing this course. Get some advice from people in the aeronautical or aerospace engineering department of a university. Also, talk to some people who are experienced with boats who know the typical water conditions in bodies of water like those in which you might operate. With a team of experts in those fields, you could develop your own simulation to develop the concept with a sound base in reality. I wrote my own simulations as a working engineer for parachutes, airplanes and for spacecraft that must land on runways. That sort of thing is a normal business task for a working engineer. Commercial simulators can only be used when they directly apply to the problem.

I remember seeing fanciful drawings of vehicles with hydrafoils and low-aspect ratio wings on covers of science fiction magazines. There are good resons why they never happened. I got an "A" in an aeronautical lab design project in school for making and testing a plenum-chamber ground effects machine powed by a 40 psi machine shop air supply. I could stand on it and slide around on a concrete floor. It was a good way to dent your backside. The value of a ground effects machine is that it can run from water onto land and back again. The vehicle you discuss can't do that. It is just a fast boat. But there are boats today that easily go 70 knots on water. How fast do you need to go across a small lake or bay? If you want to go farther, then you must except 2 meter waves as normal and 6 meter waves as occasional problems. They don't bother an airplane flying above 2,000 ft. A surface proximity machine could work fine over frozen lakes.

In any application where your vehicle could work, an airplane works better. If you can dispute this, go ahead.

[irelectronic]

Thanks Goodrick.
Yes thats right but i can't forget my idea. (Increasing Wave hight to 6 meters!!)

[Allan_Lowson]

There is a formerly payware Russian A-90 Orlenok aircraft now available for free from alphasim.co.uk.

The file name is ALPHA_A-90_Orlenok.zip and may be available from flightsim if not alphasim themselves.

They admit it is a fudge due to the limitations of FS.

I have not loaded it myself, so I have no idea what it is like to fly or whether you can see Sarah Palin or any other Alaskan from the cockpit.

[irelectronic]

Thanks Allan_Lowson
And thanks Goodrick about his very useful and nice guides.
I download thats file and fine.
In fs2004 i measure GPS Altitude (With FSUIPC.dll) in water and by follow changing the altitude ai saw in fs9 20 to 30 cm vawe lenght can be simulated and affect on crafts. but this value fixed and don't change by changing weather conditions. For Wig Craft flight simulation, I thought Ground effect very important than Hydrodynamic because after increase crouse speed Wigcraft left water. and we can simulate Wig Craft but not fully simulate wig craft behaviore.
Have any Idea for this Claim?

[irelectronic]

Can i Design a simulation engine and simulate WigCraft when thats in water (On Ground (or water) Signal can be Read by FSUIPC) and apply data to FS2004 in Slew mode and when Craft left the water surface (On Ground Signal = 0) turn off my simulation engine and push fs9 into normal flight?

By this idea we can simulate hydrodynamics myself and when in air using fs9 simulation engine for better Performane.

[irelectronic]

After a month styding on X-plane, i found witch x-plane simulate Ground Effect and Sea State up to wave hight 20 feet. by this capability we can design Wigcraft cearfully in x-plane. but when i change sea water wave conditions, visual scene not affected and water wave hight not change by sea condition setting. !! Please some one help me on thats limitation.

[Tom Goodrick]

You will have to look for a Web Site that deals in more detail with X-Plane. It is a good program but most of us find the Microsoft Flight Simulator suitable to our needs. It is very troublesome to use two different simulators. You may very well find what you want with X-Plane.

Good luck.