3-in-1 Car

[IsaacAsimov]

I have a really neat idea. Engineers should be able to build a car that travels on land, air and sea. The main method of locomotion would be in the wheels.

For travel on land, the wheels would be vertical, and travel on roads, which of course is possible. They are just called cars, or possibly landcars.

For travel through the air, the wheels would slowly turn to a horizontal position, and start rotating within the tires. The wheels would have small wings in them, which would provide lift when rotated. The car could take off and land vertically. The cars would be called aircars, skycars, or flying cars.

For travel on the sea or lakes, the car would be driven a short distance into the water, then the wheels would turn to a 45 degree angle, and start rotating within the tires. The small wings on the wheels would propel the water backward, thus pushing the car forward, as in a motorboat. The cars would be called seacars or watercars.

Of course, all 3 functions could be used in the same car. I'm not sure what size the wheels should be: I was thinking 15-inch. The resulting car would be called a 3car or supercar, or something else. I think this type of car could be built. Does anybody else have any thoughts on the matter?

 

[Curious layman]

2 out of 3 ain't bad. Just got to work out a way to merge them.

[Phi for All]

21 hours ago, IsaacAsimov said:

, and start rotating within the tires.

<snip>

, and start rotating within the tires.

Please describe this mechanism. How does a tire, which needs to grip tightly to the wheel with no slippage so it can be inflated, allow a wheel to "start rotating within the tires"?

A big problem here is that any kind of propeller has a completely different function than any kind of wheel/tire. Displacing fluids is an entirely different engineering problem from maintaining traction, so asking the same device to do both is problematic. 

[IsaacAsimov]

Yes, I realized the same thing. How about using 18-inch wheels, and having the last 3 inches attached to the tire, while the inner 15 inches would rotate very quickly?

If the car could be made waterproof (the Japanese are good at this), the car could go underwater, which would be a 4th mode of transportation. The 4 wheels would be vertical, but at right angles to the direction of travel. The car could be called a quadcar, 4car, or supercar.

I'm not an engineer, but I'm very creative. Thank you for replying.

[zapatos]

I think there is little question that given time, the right people, and a  great deal of money you could develop such a vehicle. The problem is that it would be out of the price range of nearly everyone in the world, would not perform any function as well as a purpose built vehicle, and would be primarily used for only one (maybe two) functions. 

I can make something that is a knife, fork and spoon at the same time, but why would I?

[IsaacAsimov]

A knife, fork and spoon are usually used for eating different types of food, so we are better off if they're separate. Usually, only a fork and knife are needed to eat food.

So, about the car: If you don't have a lot of money, you could just buy the car. If you had a somewhat large amount of money, you could add the skycar feature. If you had a large quantity of money, you could add the boat feature, and if you were rich, you could finally add the underwater feature. There's nowhere in the world you couldn't go in such a car!

[zapatos]

I don't think you have a thorough understanding of how business works.

[Janus]

https://en.wikipedia.org/wiki/Amphicar

I actually saw one of these back in the '60s.  We had just finished a day on the lake with my uncle's houseboat, when we saw one come in off the lake, up the boat ramp, and drive off.

The flying part is another issue.  Your idea of small wings on the wheels just wouldn't work.   There is no way that they could generate enough lift.   While there are some designs for flying cars that use a four propeller system somewhat similar to used by drones, those propellers are set out quite a bit from the body of the car and use cowlings to maximize lift.

And the idea of  such " multipurpose" wheels is just bad from the get go.  It's just too fraught with things that could go wrong. When you are up in the air , the last thing you want is to have to rely on an overly complicated system to keep you up.

 

 

[zapatos]

35 minutes ago, IsaacAsimov said:

A knife, fork and spoon are usually used for eating different types of food, so we are better off if they're separate.

A car, plane, boat and submarine are usually used for different types of transportation, so we are better off if they're separate.

[Phi for All]

2 hours ago, IsaacAsimov said:

Yes, I realized the same thing. How about using 18-inch wheels, and having the last 3 inches attached to the tire, while the inner 15 inches would rotate very quickly?

As Janus points out, you couldn't generate enough lift for a regular car to fly this way, let alone a car also engineered to move on/under water. Also, being part of the generation that was told we'd all be in flying cars by now, I've had plenty of time to rethink the whole idea of commuters flying around the cities. People can be horrible 2D drivers, and I don't see that improving with another degree of freedom. Collisions are worse when you add gravitational acceleration.

What circumstances or jobs do you see this vehicle being a better choice for? When does one need to use so many different modes of transportation? Are there many situations where you need to fly till you hit land, then drive to a body of water where you can use your boat functions? Couldn't you just fly to the body of water and skip driving? I see this like carrying around a big multitool in my pocket. It's great to have so many options, but I'm probably going to use the knife blade and the screwdriver the vast majority of the time. Meanwhile, I'm always lugging around the corkscrew and the leather punch and the metal saw and the wire crimper....

As zapatos points out, when we try to combine too much tech into one piece, it often fails to function as well as the individual pieces did. My phone is pretty state of the art, but it's not as good a camera/alarm/game system/reader/or even phone as individual pieces I've had. 

[IsaacAsimov]

Well, the way I see it, is that the bigger the wheels on the car, the more blade surface you can fit on it, and the greater thrust you will have. I would suggest 19-inch wheels inside larger 20-inch wheels, which would be attached to the tires. The car might have to be jet-propelled like on an airplane. Actually, I don't really know how thrust is generated on an airplane, so I'm going to search for it on the Internet as soon as I finish this post. Cars that fly will probably have to be computer-controlled, and may have to fly inside different flyways (similar to highways) to avoid collisions. The flying car is just more efficient than a regular car, which has to stay on the ground and travel on roads, while the flying car can fly directly from point A to point B. You could fly it directly into a lake and then activate the boat function, which would just be for fun in your free time. Going underwater would also be for fun, and you could observe many underwater life-forms. The boat and underwater functions could also be computer-controlled. If you just wanted the car for efficiency, you could just have the flying car option and leave out the boat and underwater travel options. That's fairly simple, isn't it?

 

[zapatos]

3 hours ago, IsaacAsimov said:

That's fairly simple, isn't it?

No

[Curious layman]

A flying boat car is one thing, but the ability to go under water as well? It would add so much weight it would be a terrible car and an even worse plane/helicopter. Not to mention you'd need to run your car on a battery in most places soon, adding even more weight, you could make a hybrid I suppose, but would it be powerful enough to lift a car, a helicopter and a boat/submarine all at once?

Rather buy a Porsche, a boat, and a quadcopter separately personally.

As for using the wheels as the as propulsion/lift, maybe something like this-                              

YEE flying car-  although they admit its currently impossible, unfortunatelyhttps://cooolengineering.blogspot.com/2013/02/yee-flying-car-concept.html

or something like this maybe..

Came across this aswell, a submersible plane 

Doing two seems to be achievable, even useful, especially for military, but all three/four together seems too impractical, pointless even.

Edited September 10, 2019 by Curious layman

[IsaacAsimov]

I agree that doing two seems to be achievable, such as a car and a flying car, where all 4 wheels would be used for vertical takeoff and landing (VTOL), and then tilted forward for flight. The key to these vehicles would be the 4 wheels of the car, which would have blades to produce thrust. If they don't work in a flying car, use jet engines. For three (a boat), the car's wheels would be tilted at an angle and its blades would be partially submerged to give it forward thrust. For four (a submarine), the wheels would be vertical, but at right angles to the direction of travel, so that the car could go pretty fast, and naturally sink below the surface of the water due to its weight. I thought of a fifth method of travel (a hovercraft), which the car could accomplish by tilting the wheels parallel to the surface of the water, which would provide upward thrust greater than the car's weight, which would lift the car a short distance above the water, and the car wouldn't sink because the air would bounce off the surface of the water and hit the car, thus producing more thrust. So there you have it: The 5-in-1 car!
 

[Raider5678]

4 hours ago, IsaacAsimov said:

I agree that doing two seems to be achievable, such as a car and a flying car, where all 4 wheels would be used for vertical takeoff and landing (VTOL), and then tilted forward for flight. The key to these vehicles would be the 4 wheels of the car, which would have blades to produce thrust. If they don't work in a flying car, use jet engines. For three (a boat), the car's wheels would be tilted at an angle and its blades would be partially submerged to give it forward thrust. For four (a submarine), the wheels would be vertical, but at right angles to the direction of travel, so that the car could go pretty fast, and naturally sink below the surface of the water due to its weight. I thought of a fifth method of travel (a hovercraft), which the car could accomplish by tilting the wheels parallel to the surface of the water, which would provide upward thrust greater than the car's weight, which would lift the car a short distance above the water, and the car wouldn't sink because the air would bounce off the surface of the water and hit the car, thus producing more thrust. So there you have it: The 5-in-1 car!

Uh huh.

I don't think jet engines work the way you think they do. They take air, speed it up, and use that to create thrust. However, that requires intake of air, which you can't achieve hovering because you have to be either moving at high speed to get that much intake or you need to have some sort of fan type of thing(and then you question where that's getting it's intake.) Jet engines won't work unless it takes off like a plane.

And the hard part here is mathematically calculating how much thrust you'd achieve from Wheels with air blades inside of them. What rotational speed are we talking about? What drives the wheels when they rotate? It obviously can't be the drive shaft connected to the axles, otherwise they couldn't rotate. Maybe electric motors, but then you have the issue of whether or not they can spin it fast enough and over come the resistance required to produce that much thrust.

As for the submarine idea, how do you equalize the pressure? How do you prevent it from sinking too far, since you already aluded to it naturally sinking below the surface due to the weight?

 

 

Edited September 16, 2019 by Raider5678

[Ghideon]

10 hours ago, IsaacAsimov said:

naturally sink below the surface of the water due to its weight.

Is this car idea serious? 

A subcompact car* has an interior volume of 2,405–2,830 liters (engine compartment, tires etc excluded)

A Passenger cars compact* (PC/C) weights 1100 kg–1360 kg. So a regular car will float if sealed.
Your idea is to build a car that weighs about 2 to 3 times more than a standard car does? And then make it fly by using four small propellers? From a commercial point of view; how is the fuel economy for such a vehicle if it is even physically possible?

Example as comparison: R44 Police Helicopter has a maximum gross weight 1134 kg**. You propose a vehicle that is 2-3 times heavier than that helicopter and make it fly by using four 17 inch propellers. 

Second example: A commercial drone fitted with 21-inch propellers weights approximately maximum 15 kg*** at takeoff.  

*) There are different classifications; examples used to illustrate taken from https://en.wikipedia.org/wiki/Vehicle_size_class 
**) https://robinsonheli.com/r44-police-helicopter-specifications/
***) Example: https://www.dji.com/matrice600/info#faq

[dimreepr]

5 hours ago, Ghideon said:

Is this car idea serious? 

Well, M did ask but Q just rolled it's eyes.