Back in 1989 the world was graced with the concept of Hoverboards- a creation used by Marty McFly to escape from the clutches of the town bully, Griff. The Hoverboard is shown as a skateboard like device that levitates about 3 inches off the ground and for some reason functions like one too.
Come 2018, the functionality of the Hoverboard still remains far from reality. The engineers fantasy seems as much of a reality as the floating cars observed in the cartoon television show, The Jetsons and while Elon Musk did deploy a Tesla into space, that’s the closest we’ve actually gotten to ‘floating cars’.
Most of the devices we refer to as jet packs are actually rocket packs, sometimes called rocket belts. The difference between a rocket and a jet is significant. A jet intakes air, compresses it with a turbine and pushes it out the back, mixing it with fuel and combusting it in the process. The oxygen in the air is a key ingredient in the combustion phase, so a jet needs a constant air intake to work. A rocket carries all its fuel and oxidiser (which may be liquid oxygen or some other chemical), mixes them together and combusts them. No air intake is needed. Due to the whole combustion aspect of these devices, they are generally still considered a little unstable.
‘So where did we go wrong? Why isn’t ‘Back to the Future 2’, a movie that inspired thousands of young engineers to experiment with the concept of personal flight a reality yet?”
Well, to put it simply, the technology required is still at a ‘primitive’ or beginner level. A few companies like Zapata have made efforts and have managed to create hydro and jet-powered technologies and products, however flight time is still relatively low lasting barely 6 to 10 minutes and travelling at 140km/h currently. With these specifications one wouldn’t really be able to travel long distance or truly use it for personal travel.
Despite the fact that this is a significant advancement, it’s still not safe for public use and still not something you can buy off an Amazon or an Ebay.
To understand why Hoverboards are such a structural engineering nightmare, one must delve into the physics of it all.
“Hoverboards require a certain weight to fuel ratio, in order to take off and the material used needs to be lightweight yet durable at the same time. It should be able to handle the weight of an average adult, which let’s say is around 79kgs max.”
However, in order for the hoverboard to be able to increase its capacity and runtime, the manufacturers would have to increase the amount of fuel/battery that goes into it, thus making it heavier and harder to float off the ground. While most manufacturers are currently experimenting with hydro powered jetpacks and hoverboards, those require a solid amount of water in close proximity in order to propel them upwards.
Another major issue is the amount of noise these futuristic machines produce. If companies like Zapata plan on handing these machines out to the military and using them on stealth missions, they need to invest in heavy noise reduction measures as the current iterations are really loud and disruptive.
Currently, these machines are a little difficult to get a hang off and require professionals and trained individuals to man them. A company called Hendo asked pro-skater, Tony Hawk to demonstrate their Hoverboard, the Hendo Hover, and even he took some time getting used to it. They can also be a little dangerous because much like a Segway, a hoverboard requires individuals to strategically shift their body weight as a way to turn the machine and this could be miscalculated and lead to a fall. Depending on the height at which the hoverboard is floating, this could prove to be potentially fatal.
“As stated earlier the material needs to be lightweight and durable in order to fly high, hence using a metal component wouldn’t really be a feasible option and would make the device sturdy but heavy.”
A simple solution to this would be to use components made of Carbon fibre, Nylon or Poly-carbonate. Manufactures can actually make use of 3D printing to put together prototypes or the parts of the machine in itself. Poly-carbonate in particular is known to be impact and heat resistant, making it an ideal material for 3D printing sturdy components.
However, the material is known to absorb moisture from the air while printing which can lead to defects in the final print.
The typical solution for this issue is to remove the Nylon spools from the printer once you are done using them, and store the spools in an air-tight container along with some desiccants to remove the moisture from within. If you do not want to constantly mount and remove your filament spool, there are also commercially available storage containers that will keep the filament dry, while allowing it to feed out of a hole in the container.
When it comes to using Nylon, the material is pretty solid and flexible and is also known to be impact resistant, handling hits from hammers and other hard objects pretty well. While Fibreglass is a newer material, it is known for being impact resistant and sturdy as well. These are just a few examples of how these kinds of 3D printed materials could aid in the manufacturing of hoverboards and jet packs.
All in all, the world seems to be making progress in terms of self transport. With the advent of AI controlled cars, who knows what’s a possibility in the near future?