New methods of construction – light aircraft

Basic methods available: Wood, fiberglass, carbon fiber. And of course aluminium.

The most alluring is Carbon Fiber (CF). It aint perfect though. I hear at optimal result CF is maybe 28% better than aluminium. Also CF is basically carbon fiber twill weave mixed with epoxy resin – which is basically plastic. Again CF aint perfect. But have you seen the Youtube vids of what it CAN do? Ferrari makes drive shafts from it that have incredible lightness and strength and there are demonstrations of thin CF tube frames holding cantilever hundreds of kilograms, for the weight of the CF tubing itself being very very minimal like 5kg or something. So it has its good points too. Also you can use other materials with CF to make composite properties such as Kevlar twill weave.

Here is a composite aircraft prototype build:

 

 

This here was one of the best old-school construction methods:

3D Printed aircraft

One day soon you could go to a kind of 3D printer place where they have a huge 3D printer that can print any large components – like a printer the size of a tennis court, and take your plane plans and pay to have your plane printed out on the big 3D printer. Also, the actual printed material could be plastic, plus embedded carbon fiber thread. So then no need for the laborious process of making your own moulds. FYI by the same process you could print out a car chassis, or a boat. The design would cost maybe $1000 but you can select from many many designs, some of them free open source etc and you can see the user rating for each design how many stars they gave it, did it work well etc. A bit like Apps in the App store you can see how popular it is by how many downloads it has achieved and things like that. You could buy a P51D Mustang or a FW190 and then get it printed. The printed 100% scale warbird airframe might cost $12000, which would comprise the cost of the material plus the use of the 3D printer.  Maybe add another $5000 to the cost if carbon fiber thread was included in the otherwise plastic build.

Much of the innovation in light planes these days is actually coming firstly from the remote control plane world. Example jet engines. So its no surprise that the best ideas in 3D printing are found in the making of RC planes.

Apparently to achieve optimal strength a CF part must be cooked in an autoclave (oven) to quickly harden it, instead of just letting it dry and set at room temp. So the two big components of CF builds are vacuum-bagged moulds and autoclaves. And who has those laying around? I conclude it is tending towards innacurate and untimely to make moulds by hand because they need to be perfect dimensions, but a computer controlled 3D printer would make accurate moulds. And before you can build even one complete plane, you need a complete set of moulds.

It would be good if autoclaves were not required because then one wouldnt need an autoclave big enough to fit an aircraft wing in it or a fuselage etc.

Making a CF wing in a mould:

One could experiment with other substitutes for resin as well, such as how about a thin amount of molten aluminium be applied to a CF fabric? CF is not going to burn at molten aluminium temps (I think) and so you could get rid of the plastic resin and replace with a really thin aluminium impregnation of the CF twill.

Anyway, my basic idea here is to use a 3D printer to make many many mould sections that would fit together to make complete component-moulds – of which there would be many, and then use those moulds to make the components for the plane. This way completed wing moulds could make an aircraft CF wing and same for the fuselage and tail planes.

Some planes are quite small, for example a good project plane would be the Cri Cri. Imagine a jet powered Carbon Fiber Cri Cri made from components layed-up in a series of 3D printed moulds.

A standard Cri Cri (Note: even it has a CF instrument panel):

Further: Once you have the mould set, you can recreate more planes from the mould set.

This all presumes a monocoque construction – where the skin of the plane gives part of the structural strength. But you could try another route and just use store-bought CF tubes glued and fastened together to make a skeleton airframe that then gets a dacron skin. Like with ultralights like the Phantom, only the aluminium tube is replaced with CF tube.

With the 3D printed mould idea there is great scalibility and reproducibility. You wouldnt need to be a master craftsman to make the moulds to the required exacting dimensions because the printer would make what the instruction specified, same result every time.

Desirable characteristics

Cars now a days have a passengers safety area (designed to not deform) and crumple zone which is designed to progressively crumple and deform and in so doing to decelerate an impact. Its tried and true. Light planes could take advantage the same ideas. Racing cars have made great strides in driver safety, Formula One cars are reputed to have very safe driver compartments made from CF composite.

VTOL: The new concept now within our reach is rough field or farmers field landing and takeoff where the runway is long enough for a STOL plane a not much more, or even VTOL. This can be achieved with multiple smaller engines – either piston, electric or jet, or combination, that can be tilted upwards and controlled the same way one controls a RC drone such as a DJI Mavic etc. This is already proven here:

 

The Holy Grail of light planes in my opinion incorporates these kind of features and is easy to fly, takeoff and lands anywhere, is structurally resistant and safe, is not prone to breakdown, doesnt need very much specialised maintenance or training to operate and is cheap to build and run. Honestly I think the ingrediant components are already here, it is now just waiting for someone to put them all together.

Lighter than Air

Also there is a lot more that can be done in the area of lighter-than-air aircraft.

Here is the best solar balloon I have seen, it demonstrates that the sun alone – on a zero wind day – can lift a man into the sky.

My idea was to make a large hybrid fixed wing and lighter than air machine that could be at least neutrally buoyant and gain more lift to fly from the wings and low speed cruise.

Basically visualise the amount of big balloons required to lift one man, and place those balloons into a light weight airframe of a bulky scale fixed wing plane. You would get the benefit of lifting gas, with less of the susceptibility to wind and other great features like the ability to control direction of flight. The big problem is how to expand and contract the airframe with changes in atmospheric density and altitude. – To keep your lifting power as you ascend, you need to be able to expand your lifting volume. Thats an engineering problem that needs to be solved for a hybrid lighter-than-air / fixed wing aircraft to be a reality. A simple rudimentary way to do it is to make a CF frame fuselage and fit balloons within and on it. Its very crude though because it would generate a lot of drag.

New materials would be needed that have these properties: the envelope that contains the lifting volume needs to be capable of retaining the gas within it for basically a permanent basis. It also needs to be able to expand and contract with altitude changes. In the same way a rubber weather balloon does, but the material would not be so porous and would be much lighter than rubber. Mylar already exists as a great store of lifting gas, but it does not flex and stretch. Another idea is to use heated air – the heat from engines could be fed into the lifting envelope. Or Hydrogen could be used cut with some inert gas that is also fairly light weight but that might reduce the volatility of the Hydrogen to something acceptable. Helium is so expensive, it is almost not worth it, unless you can be sure your lifting envelope will not be porous. The concept of buoyancy bladders is in nature already – How fish keep their place in a volume of water by using buoyncy bladders.

 

 

Then theres the jet packs:

Kind of a gimmick, obviously these jets are best deployed on fixed wing aircraft in a way that can offer both normal flight and STOL/VTOL.

 

Paramotors

Paramotors are capable personal transport solutions, however they are susceptible to the wind and turbulence. They are kind of like the motorbikes of the sky. My suggestion to paraglider wing designers is to make a un-collapsible wing, by making a wing that is made rigid by pneumatic inflation.

 

hang glider/conventional aircraft hybrid

So this is one of my favourite planes ever, it is so beautiful and its a next level idea. The designers are a hang gliding background, but its an actual aircraft, but made in a way of construction and with same materials for hang gliders. It shows the way for a really excellent genre of personal aircraft that are going to be capable of meeting most of my criteria for what a light aircraft should be.

Here is an unconventional design:

 

Here’s another flying wing:

 

Compare and Contrast the two vids below.

Old school fiberglass layup techniques for Rutan aircraft:

Modern 3D printers for making RC planes – Check out this 3D printed Sabre:

New methods of construction – light aircraft

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s