How can a vehicle fly?

 

How does a flying vehicle achieve flight?

Basically, there are four main ways to do this. It's all explained in the video below. Do take a look.

A summary of the contents of the video are given below.

Method one: Lighter than air

To achieve this, a vehicle must be lighter than air. Think of, say, a helium balloon, or a hot air balloon, or an airship. This type of flight uses the Archimedes principle to be airborne. Basically, the upthrust on anything in a fluid is equal to the weight of the fluid it displaces. If a vehicles displaces more air (in terms of weight) than itself, it will float.

It’s pretty easy to accomplish, if you can find a gas that is lighter than your ambient air. Helium can be pretty expensive. Hydrogen is an option, but it’s very flammable when mixed with air. Hot air is a pretty good compromise (the gas itself is not flammable), but you need a fuel source to, well, heat the hot air.

In this type of flight, you can change altitude by changing the overall density of your vehicle. This may be by reducing the amount of your lightweight gas (to loose altitude) or dropping something heavy like basalt (to gain altitude).

Method two: The reaction from a downwards force

Here, you can direct air downwards to create an upwards force that keeps your vehicle airborne. Think helicopters and jet packs. The advantage here is you can take off from pretty much anywhere and the vehicle isn’t massive like in the previous case.

The disadvantage is fuel requirement. A helicopter is more efficient than a jet pack, but you still need to produce enough lift to counteract the vehicle’s weight.

Method three: Fixed wing

Here, you use the shape of a lifting surface (wings or the whole vehicle) to create an upwards force based on speed. This is generally more efficient than straight up producing the thrust to lift it up. Think airliners and general aviation and fighter jets. These are, unsurprisingly, fast.

You can also have the unpowered version in gliders, where you can use air currents to generate the lift you need.

The problem is landing and takeoff. You need a long, clear area to take off and land. Because of the high speeds and the proximity to the ground, landings and takeoffs can be relatively dangerous. Modern airliners and airports are designed to be very safe. However, if you’re dealing with, say, the early days of aviation or a society that is just discovering this type of flight, it could be a point you can consider.

Method four: Flapping wing

This is what’s seen in most birds (the larger ones who glide a lot mix it up with fixed with flight quite a bit, and smaller ones may be going into a completely different type of flight). 

There have been man-sized ornithopters (as they are called) as well.

It’s pretty efficient, but the problem mechanical complexity if you want to make a machine that uses this type of flight. You can take off from most places (heavier birds still need a runup), and you can change to the more efficient and faster fixed wing flight once you’ve taken off or if you want to glide.

In short...

These are not the only ways you can achieve flight, but these are the most practical methods for vehicle sized things.

Expect more flight related videos and articles in the future.

Please let me know what you think in the comments, and please ask if you have any questions.

See you next time!