Can wheeled vehicle run on the surface of water at high speed?

[slboatdesing]

Continuing to explore.

I found a video of a dune buggy skipping in Iceland, racing against a snowmobile. Hard to describe, see the video. Top Gear no less. 800 hp on a large, heavy two seat vehicle to go at about 50 mph which is I think is about as fast as you can go in a speedboat of that horsepower. Of course a speedboat does not have wheels, and is lighter. The concept works, it is just not known how efficient it is. My idea would be to engineer it so that it floats in still water and runs over water at speed.

Have a look:

 

[slboatdesing]

This design gets as close to my original concept - add floating rubber spheres to the catermaran with axles and you have it. If rolling resistance is lower than sliding resistance over water, better use the rollers. I suspect it is, given the fact that an aquaplaning car does not slow down appreciably, and one is not supposed to apply the brakes possibly due to one wheel touching the surface of the road or slowing down, it is not clear.

Unlike a hydrofoil or hovercraft, the concept must be able to float in still water with the power off. Seeing those hulls go up and down in rough seas is a bit disconcerting to me, smaller swells will be just swell. A mechanical system on a smaller craft is what I had in mind, without expensive electronic and software controls, after all, early cars had a totally mechanical suspension after all.

Martini 7.0 Catemaran

CGI Videos - "Martini 6.0"

Also the Nauticraft

 

[comfisherman]

That Icelandic rock climbing truck with the paddles is an older design so maybe a 350 or an early ls1. We have similar chasis type rigs here with similar hp, they can on heavy throttle consume gallons per minute. I'd Hazzard for the several shots they did with Hammond they were burning more than a gallon a mile.

 

[slboatdesing]

These are heavy trucks. My bet is that at speed on the surface of water, which amounts to a mushy rough road, the power needed to maintain speed for a wheeled vehicle cannot be very high. Weight capacity is another matter altogether and from that point of view it may not be feasible.

The concept is modified with more low pressure flotation tires made out of same material that inflateables are made out of, and in a catamaran configuration. The thing will float in still water, when it gets up to speed, which may require considerable power, it will start rolling on water, and then power may be reduced.

A scale model will settle the issue to a great extent. Either that, or fit an air-boat with several rotating lightweight wheels and check the power settings over water at various weights.

Another way to test this is to add wheels to an airboat. If the air-boat travels faster with the wheels, and the added weight, or at certain weights, then the concept can be developed further. It could be thought of as an amphibious air-boat. Are there any?

 

[Wavewacker]

I might save you some money. In the 60's I had a VW Bug, pretty much gutted, Baja front end, larger tires but just mud tires.
I stuffed rags in the heater vents in the back at the engine and inside along the floor channel. Used flexible exhaust pipe tubes over the pipes and screwed them up higher on the body above the engine lid. I'd drive the car in the Finley River, back wheels spinning pushed me forward, it floats, I'd jump from sand bar to sand bar, the car would lunge forward as the tires hit the bottom. It was just fun, just caulk up an old VW Bug and go for it.

 

[portacruise]

If it requires around 50 mph to get up on top skimming, my guess is it can't be done with spherical Wheels starting from the stopped floating position. Seems to me like a spherical wheel would have the least resistance when being pushed and non-powered, but also the spherical shape would have the least traction when needing to deliver huge power required to get up on top? A wheel with nubs projecting from the side walls might give the required traction to accelerate from the stopped floating position, with a reduced profile when the vehicle is up on top, assuming that a reduced profile is required at speed for better efficiency? If skids are not used, it would appear that all Wheels must be powered to accelerate from the stopped floating position (and maybe stay up on top), four-wheel drive is required for 4 Wheels, 6WD for 6 Wheels, etc?

 

[slboatdesing]

I'd drive the car in the Finley River, back wheels spinning pushed me forward, it floats,

Pictures would be nice. What would that 30hp? Or so motor do if it was connected to a propeller like the airboats and 'air cars'?

Floating is good, I want the thing to float so high that after gathering speed on the motor driven propeller at the back, it starts to plane on the water, then the wheels start rolling on the water, reducing resistance. To the wheels it would seem like they are on a bumpy road. What if it was your car with just the wheels and tires and a propeller? Or fix your wheels and tires to a airboat?

The Hydrocopter is the closest thing I have found to what I am looking for - a hydrocopter with flotation tires would do it.

 

[slboatdesing]

Seems to me like a spherical wheel would have the least resistance when being pushed and non-powered, but also the spherical shape would have the least traction when needing to deliver huge power required to get up on top?

That is why I am proposing that the wheels be non-powered. If the wheels were large enough, they would float at about 10% of their height, and after being pushed along , they would aquaplane, then they would start to rotate just as on land. Little ridges across would help them rotate. As a plus the craft would also be amphibian. Weight matters, I am not suggesting running a heavy buggy on these wheels. As a proof of concept, the air boat with wheels should work fine. Run the airboat as usual, note power settings vs speed, then add the wheels and see how fast it goes on water at those same settings. On land it would be much faster with wheels I can guarantee that.

I revised the model with larger tires and moved them up to more or less level of air-boat hull.

Would a scale model prove the concept or would the scale effect be too complex to deal with?

 

[slboatdesing]

This 'similar thread' has some similar ideas, though the tracked vehicle looks mechanically complicated and prone to wear and tear. (DARPA)

brainstorming for a 'micro' 2TEU container/2x vehicle RORO cargo haul https://www.boatdesign.net/threads/brainstorming-for-a-micro-2teu-container-2x-vehicle-roro-cargo-haul.56639/

There were amphibious trucks that could load/unload cargo from ships to beaches during WW2. Some remain in service.
DUKW - Wikipedia https://en.m.wikipedia.org/wiki/DUKW

Big hovercrafts are better. Now that they are out of service in Dover for 15 years, some may be available.
BBC - The last flight of the Hovercraft out of Dover http://news.bbc.co.uk/local/kent/hi/people_and_places/history/newsid_9048000/9048330.stm

This thread also has some great ideas: four human hamster wheels with a propeller attached? the Hamster wheel illustrated the point - how fast would a human be able to push that thing through water if it was stationary? I think we are getting close..

Amphibious Paddle Wheeled Canoes. https://www.boatdesign.net/threads/amphibious-paddle-wheeled-canoes.59038/

 

[kerosene]

Continuing to explore.



Have a look:

Seen many clips of these icelandic buggies crossing water but also dipping in when the suspension oscillation gets too large.

 

[Wavewacker]

Pictures would be nice. What would that 30hp? Or so motor do if it was connected to a propeller like the airboats and 'air cars'?

Floating is good, I want the thing to float so high that after gathering speed on the motor driven propeller at the back, it starts to plane on the water, then the wheels start rolling on the water, reducing resistance. To the wheels it would seem like they are on a bumpy road. What if it was your car with just the wheels and tires and a propeller? Or fix your wheels and tires to a airboat?

The Hydrocopter is the closest thing I have found to what I am looking for - a hydrocopter with flotation tires would do it.

Stock it was 36hp, lol. The water line was about 10 inches up the side doors. I thought about putting a bolt on paddlewheel on the rear wheels, but never got that far.

In the mid 60's, state of the art photography by most folks was a polaroid camera, my Dad wouldn't let me use it unsupervised. Sorry, no pictures.

Might save some money just buying one of these, Amphicar based on a Renault.

 

[slboatdesing]

The amphibious vehicles are very interesting things, no doubt. A hydrofoil amphibian would be fast and land and water.

I am not talking about amphibious vehicles: water craft keep skimming over the water, planing on the waves all the time. All I am asking is how to reduce friction of the contact patch? An age-old solution to sliding things over distances has been to use rollers or wheels. The concept is feasible, but I am not sure how cost effective it will be.

The 'bouncing bomb' of WW II illustrates the concept. The item is very heavy, but see how the bomb keeps skipping over the water while rotating. Does it go further when rotating forwards or backwards? That will indicate how much friction is reduced by rotation.

 

[Wavewacker]

I'm not a physicist, my guess is that the direction of rotation doesn't matter because rotation at speed and some velocity lifts the leading edge above the water. It's like skipping a rock over water.

But I would question the practicality of this exercise since there are other alternatives that are more efficient, economical and reliable.

 

[portacruise]

"All I am asking is how to reduce friction of the contact patch?"

My guess is there has to be a certain balance between the total contact patch friction, vehicle weight, and minimum vehicle speed that have to be just right for this kind of skimming to work. I think it's a lot like skimming a rock. Skimming a rock doesn't work if the rock is spherical or has tubular shape tumbling without enough contact patch, or if it is too heavy for the contact patch, or if you don't throw it hard enough ie. if there's not enough speed coming into the water surface and being maintained at the water surface afterwards. The tire design which I mentioned previously would allow for flotation from the additional volume of sidewall Nubs, while allowing for a smaller contact patch from the narrow outside circumference of the tire once the vehicle gets up to skimming on top and the Nubs no longer touch water.

The main drawback of such a vehicle would be the clear running distance needed to start Plus high power required to sustain the skimming, compared to some of the other aquatic vehicles that are already in use.

The Bouncing bombs would not travel as far all things being equal, if they were tumbling, or spinning backward, JMHO. But given enough huge launch speed and spin, perhaps even a pig would skim albeit for a shorter distance, haha!

 

[comfisherman]

Louisiana swamp dragsters..... start in the water and get to skimming.

There is your prototype...

All you need is a funny fuel dragster on tractor tires. Should bee good and green getting several hundred feet per gallon.