Wing In Groundeffect in Rigger3, How to do it? Options

[Gerzel]

First off here is a page explaining what these things are: http://www.se-technology.com/wig/index.php

Basically they are a plane that flies low to the ground to get improved aerodynamic properties. They are similar to a hovercraft except they generate their air cushion by their forward movement rather than dragging it with them.

The page includes comparative graphs with power to load ratios and comparisons in fuel economy etc. So I think it should be possible to work out what these things would look like in SR terms.

[Moon-Hawk]

Hmmmmm, sounds like either a hovercraft with a stall speed, or an aircraft with a very, very, VERY low ceiling. Either way, hopefully a watertight hull. :-)
I would say go with an aircraft with a very low ceiling, and give it an economy boost in exchange.

[Kagetenshi]

They're already in Shadowrun, and you'll probably recognize the name: T-birds.

~J

[kigmatzomat]

What the OP is discussing is a common phenomenon where the air is "thick" near the ground. It isn't a factor of air pressure as much as it is of friction; the air "sticks" to the ground and creates a highly turbulent zone that has an effectively higher viscosity and thus higher lift for vehicles with lift-generating surfaces.

T-birds use ground-effect to maximize their jet thrust, as the exhaust is in "direct contact" with the ground. This is demonstrable by the fac t that a Tbird can hover in place, while the increased lift of ground effect is only applicable with horizontal movement.

Virtually all light aircraft pilots have trouble landing the first time because they encounter the ground effect zone and the plane gains lift.

IIRC, the russians had a GEV intended to be a "supercargo" vehicle. It was intended as a means of ferrying bulk cargo fairly quickly across the ocean. It was too dangerous to fly over land (given the narrow GE window) but the ocean and its inherently denser air (due to moisture) gave it a wider operational profile.

Here's a wikipedia entry on the russian cargo vessel.

http://en.wikipedia.org/wiki/Ekranoplan

[mfb]

i used one of these as a luxury cruiser, in one game. like a cruise ship, only, y'know, in the air. i didn't bother with stats, though. i'd go with an airliner, arbitrarily reducing the flight ceiling and increasing fuel economy.

[Kyoto Kid]

...kigmatzomat, you beat me to the punch.

Saw the Ekranoplan on Wings of the Red Star.

...neat concept

[sunnyside]

Ok first of conversion to SR shouldn't be all that hard. You just need top speeds and accelerations and if you can info on fuel and weight.

I'd only use the things for NPC type stuff. It just seems the design would be very hard to maneuver and nearly impossible to use on land. Plus if they took a hit the waters right there, and if you lose speed you'll hit it, you'd think they'd have a brutal modifier for crash tests.

[Kagetenshi]

Is there any reason why it would be worse than a T-bird?

~J

[sunnyside]

Two very important differences.

#1 While not normally what they like to do, T-birds have the option to hover. Meaning that if something happens and they lose airspeed they don't smack the ground. Airplanes start off higher and glide. A WIG that suddenly loses speed due to a hit would drop.

#2. T-birds stay close to the ground, but not THAT close. Rigger 3 gives their flight ceiling as 1,500 meters for example. Certainly "low altitude" but very different from 8 centimeters or so. Even Nap-of-Earth flight is typically 15-60 meters and I'm not sure how well something in those situations would do if it had to really maneuver or take a hit.

On the other hand there is something to be said for fun and WIGs seem to be that. So maybe your WIG has jump jet capability and just uses WIG mode to improve endurance (a constant problem for LAVs!). The jump jet abilities could be tied into a drive-by-wire + sensor + autonav system so they can be used to deal with things that happen as you're going along.

In that case I would treat WIG as a design modification for a T-bird or for a smaller version use the vectored thrust UAV. (though I believe the website said that only for larger vehicles is WIG efficient, though on a smaller vehicle it would let you travel REALLY close to the surface of the road/water letting you be really stealthy. Especially if you toss in some ED.

Anyway the modification would at +1 to handling when not in WIG mode and add some load from all the wings and stuff that would get in the way of jump jet mode maneuverability. However when operating in WIG mode fuel efficiancy would increase significantly allowing the craft to travel much further than a regular T-bird.

[Kagetenshi]

I suspect the WiG plane is probably very different from 8 centimeters or so as well. On that kind of scale, almost no large body of standing water can be considered flat.

~J

[sunnyside]

You get the idea.

Actually from the WIG page it looks like you actually might want to consider using it as an extension of the hydrofoil rules. Which is how they describe it being used.

[kigmatzomat]

These "wing in ground effect' vehicles have very high cargo capacities for their speed. Check out the models here:

http://www.yachtboutique.com/Designers/Ekr.../Ekranoplan.htm

The Aries has ~40 metric tons of cargo capacity and can travel ~450km/hr at around 3L/km. Compare to a 747-8I that can haul the same cargo at 100km/hr but sucks down 15km/L. Basically, you get 5x the fuel efficiency if you limit yourself to half the speed. For coastal regions, especially for low-swell seas like the Mediterranean, these vehicles are very effective.

[Kagetenshi]

15 L/km, you mean? 15 km/L is a lot better than 3 L/km.

~J

[kigmatzomat]

Yeah, I mistyped b/c I'm not used to putting things in terms of liters per kilometer. I pulled the 747 data off the wikipedia site, just for reference.

[Kyoto Kid]

[Kagetenshi]

Take the 737 out of mass production and see what the cost does.

Edit: though according to Wikipedia, some models of the 737 sell for up to $80.5 million.

~J

[Kyoto Kid]

...that is for the most advanced models. For about two thirds the price of the Bentley Aries (cute name BTW), you can get a BBJ with a 10,00 km range & a cruise of about Mach .8.

[edit]

One of my concerns is how a GEV would handle rough seas or operations during a major strom. the BBJ on the other hand could just fly around or over it. I'm not saying that the GEV is a bad concept, & I think it would be cool to see them on the water. However for the cost it is more practical for cargo ops, high speed ferry service, and possibly some military ops as opposed to a rich boy's play toy.

Though, I will admit, watching "Unlimited" GEVs out on Lake Washington battling for the Seafair Cup would be a kick. I may have to put that into my setting.

[Gerzel]

I think it should be noted that many of these GEVs can also operate at much higher altitudes losing the efficiency boost of the ground effect, but operating as aircraft. Also since many are designed to work over water they are built seaworthy.

GEV operation is used to increase efficiency, but not as an exclusive mode for movement.

[Kyoto Kid]

...I certainly wouldn't want to be flying at 100 - 300m altitude through a North Atlantic storm. Think of the wind shear & turbulence you'd be dealing with.

They may be built seaworthy, but it would still make for a pretty rough ride when swells exceed 6M. Keep in mind you have something about as large as a DC8 62 (Gemini) to C141 Starlifter (Aries). That is significantly smaller than a ship like the HMS Queen Mary II or SS Norway both of which also have stabilisation to dampen the effects of rough sea conditions.

Turbines also have a nasty habit of flaming out when they ingest large quantities of water in a short amount of time. This constantly plagued the early turbine powered hydro racers and required design modifications to minimise the effect. Also, hydro racers generally operate on relatively calm inland waters on fair days rather than the open seas.

[DuckEggBlue Omeg...]

I saw a single person one of these on Beyond 2000 years ago that looked more like the Bat-plane than something like the ekranoplan, but as yet I can't find any thing on it. But the wikipedia article on Ground Effect Vehicles had some other links of possible interest.

The Boeing Pelican

Hovercraft/GEV Hybrids from Universal Hovercraft

The German built 'Hoverwing'

Another interesting thing I don't think been mentioned yet is that, apparently, the Ekranoplan's benefits to the Soviet Military was not just fuel efficiency, but that it flew below radar but above sonar.

[kigmatzomat]

Which makes them great for smugglers.

[Tiralee]

[kigmatzomat]

On the opposite side, they also make great antismuggling platforms. Think about it you've got a 250 mph vehicle that moves between radar & sonar, doesn't fly so high that it is visible for any great distance aaaaand it can carry a huge amount of weight, aka weapons and armor.

Just look at the wikipedia image of the Caspian Sea Monster and tell me it doesn't cry out to be equipped with multiple turrets, a torpedo launcher, and a missile rack.

[Kyoto Kid]

...actually as a military vehicle the Ekranoplan is an excellent concept. Not only can it serve as a high speed seagoing intercept, but also as a covert landing/insertion craft.

@kigmatzomat: As for smugglers, I am going to have to stat one or two of these up.

[edit]

I have a copy of Soviet Military Power 1987. I believe it has is mention of the Ekranoplan it's speculations on its deployment. I'll have to check when I get home.

[kigmatzomat]

I'm not sure I'd want to deploy these monsters in true deep water conditions. They worked on the Caspian, which really a giant lake. I'm sure the Caspian gets some significant waves but nothing like what you'd find in the deep atlantic or pacific, with literally thousands of miles for waves to form. I found at least one verifiable, scientific account of 30m (95ft) waves in the Atlantic.

http://www.spiegel.de/international/spiege...,408953,00.html

You might see ekranoplans in the Mediterranean, which I'm told is a millpond compared to the horrors of the Atlantic. Also on large bays, gulfs, or even particularly straight rivers (imagine one of these buggers jetting up the Nile).