Make a hovercraft that is wider than it is long, put a drive fan atop each side and steer with the throttles, have the air intake for the cushion in the middle where it gets un-obstructed ram-air assist.

This will allow planing on water at lower speed, simpler steering mechanics, and actually have the craft travelling narrow-wise while slaloming around corners.

Not for use in the canals of Venice.
-- baconbrain, Aug 24 2010

I can only assume Bacon has never flown a hovercraft.

Unlike almost any other vehicle, a hovercraft has no natural directional stability. Wheels, boat hulls and airframes all have a natural direction of travel and need to be steered by altering the angles they present to the road. water or air.

A hovercraft sits on a non directional air cushion. Steering changes the angle of the machine, but it is the resultant thrust angle which changes it's direction.

Slowing one of a pair of engines as described in the idea would cause the machine to begin rotating about it's vertical axis while continuing to move in an almost straight line.

Large multi engine hovercraft have all thrusters capable of steering, so the machine can be pushed sideways to execute a turn.
-- Twizz, Aug 24 2010


if yer travelling at enough of a clip that ram-assist is going to make any bit of difference, you don't want to be going sideways.
-- FlyingToaster, Aug 24 2010


well I've never flown one either, but maybe this can be used for flying down long halls (with the sideways push, you know against the walls??) I don't really know so I can't vote on this.
-- xandram, Aug 24 2010


No, I have never flown a hovercraft, but I have read books on designing them, and I have seen videos of how they turn. This idea was inspired by watching a rear-drive hovercraft crabbing around corners, which had it travelling sideways to turn.

The "steer with the throttles" bit was only intended to change the heading of the craft. I know full well that a hovercraft changes direction of travel by thrusting air the other direction. To make a hard right turn with this design, the driver will reduce thrust on the right drive fans, which will let the right side lag until the craft is travelling sideways, then applying full throttle on both drive fans will push the craft in the right direction, with heading adjusted by the differences, but direction of travel affected by overall direction of thrust. It is in a skid, like a drift car.

That isn't that hard to figure out, is it? Why the heck else would I have included "the craft travelling narrow-wise while slaloming around corners"? It twists sideways, then pushes itself around the corner. There are "round" twin-fan hovercraft that do pretty much this already--why do folks think it won't work?

If you prefer, we can change it to steering with the prop pitch, which seems to work for helicopters. Multi-engine aircraft do both pitch and throttle steering at times. Twin-engine seaplanes do exactly what I have described while on the water at slow speeds if the wind and current are against them. This idea simply takes the practices of other aircraft and applies them to a hovercraft.

As for the ram-air, I said it was an assist to have it getting un-obstructed flow, meaning; while going straight ahead. Again, that is standard hovercraft practice, achieved in a different way. While cornering, the lift fan can be sped up a bit, the craft will not be making ram-air speed sharp turns.

Again, the craft I watched the other day was travelling sideways in the turns, wide side leading.

Finally, a hovercraft on water is a planing boat. It starts out in a hole caused by the pressure of the air cushion, and, with speed, transitions up onto plane just like a motorboat does. A wide. short craft will plane at a lower speed than a long, narrow craft. Which is good for starting up, but would actually be a disadvantage for this craft while travelling slowly sideways through a turn, as its planing speed would be higher, not a lower speed like a sideways skinny craft. So there's a disadvantage.

I thought, a few years ago, about making a hovercraft that started out sideways on water, so as to plane sooner, then pivotted the fans to travel skinny-wise at higher speed with less drag. This idea was just the realization that it could stay sideways and have some advantages.
-- baconbrain, Aug 24 2010



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