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Building Model Aircraft from Plans

Issue No 27, 15 May 2023

By: Anthony O. Ives

Building model aircraft from plans is the one I miss about flying fixed wing aircraft. It is possible to build any shape of a fixed wing aircraft from wood. While I did not find flying fixed wing aircraft as enjoyable, I really prefer and have more fun flying helicopters it also took less time for me to learn to fly helicopters. However, I do enjoy making things out of wood, generally the great thing about wood is that you can almost make anything from it. The helicopter is the one exception while it is not impossible its just not really practical to make a helicopter from wood. So my sole interest in fixed wing aircraft is building them from wood and allowing me the work with wood building something that is relevant to flight. However, in more recent times there is also the possibility that a fixed wing aircraft can be VTOL (Vertical Take Off and Landing) which is closer to how helicopters operate. The process of building model aircraft from plans can also be used even if you are building a helicopter from metal and composite materials, its just that a more complicated process will be needed to make the individual components.

The plans for model aircraft are usually full scale which means that everything on the plan is drawn to size that you need, there is no requirement to scale up templates, etc. Some plans come with a build process which gives a order to build the components and order to assemby them. Most fixed wing aircraft have the four main components:

Wing
Tailplane or Horizontal Stabiliser
Tailfin or Vertical Stabiliser
Fuselage

In reality helicopters usually have the same components but will always have a main rotor and tail rotor as well. Some helicopters have an small wing but most do not and the fuselage is usually a different shape from that on a fixed wing aircraft. Generally the order which you build each component really does not matter, but I tend to build the component in order listed above. I think I do it this way because I consider the fuselage part of the finally assembly and usually need all the other components made to set up and construct the fuselage correctly. In general you should study the plans and decide the appropiate order to make and assembly the aircraft components correctly for the specific aircraft you are building.

Typically on most model aircraft the wing and fuselage components are the most complex to make and assemble. However, large model aircraft can require you to construct a tailplane and tailfin in similar way as you would the wing. In most cases the tailplane and tailfin is made cut out of sheet balsa wood using a template and can glued together to give the complete tailplane or tailfin. The process for constructing individual components is giving below:

Create templates of wing ribs or fuselage frames/formers.
Use the templates to cut wing ribs or fuselage frames/formers out of the appropiate wood, balsa or plywood, etc.
Cut to size all components needed to do intial assembly of the wing of fuselage such as spars, etc.
Using a protective transparent flim on top of your aircraft plan to assemble the wing/fuselage on top of the plan, pin the individual spars, ribs, frames/formers to the plan applying glue at the correct places.
Add other parts such as skins, shear webs after the intial assembly has dried, it is good to keep everything pinned in place until all the assembly is completed.

Templates can be created in various ways from the plans. You could use tracing paper intially to draw the outline then cut it out and then use it to cut your template out of stiff cardboard. Alternatively you could use ordinary paper (instead of tracing paper) placed on the plan with the plan placed on something like a window (or some other light source) which would give a outline of what you have to trace. I personally do not create cardboard templates I just use the intial ordinary paper template to carefully draw correct shape on the wood. How you create the template really depends how accurate you want your parts to be, in reality I think building something by hand the accuracy from a carefully used paper template is going to be good enough. Whichever way you create your templates you can then use it to draw your rib or frame/former shape on the wood it is to be cut from. Balsa wood is very easy to work with, so you could use a sharp craft knife to cut it out but with something plywood you will need to use a coping saw or an electric jigsaw.

During the construction you want to make sure your ribs, frames/formers, spars, skins etc are placed as accurately as possible according to the plan. You want to be able to pin the parts so they cannot move out of place so you would ideally place the parts on a purpose built board that allows you to drive pins into. Some people create boards out a hardwood sheet with cork pads glued on top. Someone told they used a sheet of pinewood and by using a pair of pliers to grip the stem of the pin they can drive the pin in without it breaking. I personally use a sheet of half inch thick plywood its never possible to drive the pins in fully but usually they go far enough in to hold the parts in place. You also want to protect the plan as you have to glue the parts on top of the plan so there is always the possibiliy they would stick to the plan and tear it when you try remove them. One way to do this is to use transparent plastic flim such as cling flim or the transparent plastic flim that comes of the back of solarflim. Solarflim is used to cover model aircraft [1]. You always want to hold on to your model aircraft plans as you never know when you may need to build a another wing or fuselage, also you may just want to build another aircraft.

I have mentioned solarflim which is one method of finishing and covering you model aircraft. In order to keep the weight down, most model aircraft have open structures which is required to be covered over if is fly. The simplest way of covering open structures is to use an iron on plastic flim covering material such as solar flim, these materials can also be used to cover the rest of the aircraft. There is a wide range of these plastic flim type materials varying in strength and suitability depending on whether your model aircraft is electric or fuel powered. Certain covering materials do not react well with some fuels so you need to check out the manufacturers advice whether the covering material is suitable for the type of fuel you are using. Glass fibre covering [2] is another alternative however, it is usually used in large model aircraft or just parts of the aircraft. Glass fibre covering is not suitable for open structures so the aircraft must be completely skinned all over or essentially covered in a wooden skin. Glass fibre covering is a lot more complicated and difficult to use as a covering and generally a bit of experience is needed so it will probably take longer the first time. Glass fibre covering has also the disadvantage that it can add extra weight but advantages are that more strength is added, is easier to repair, is suitable for most fuels and allows you to apply any paint scheme you want. I also heard people using other covering materials such as brown wrapping paper however I have never used them myself so not sure how easy or successful they would be.

The picture below shows various different phases of construction of model aircraft:

Phases of Model Aircraft Plans

In a future article I will talk about how it is possible draw your own model aircraft plans which is not all that difficult for small model aircraft designs.

Please leave a comment on my facebook page or via email and let me know if you found this blog article useful and if you would like to see more on this topic. Most of my blog articles are on:

Mathematics
Helicopters
VTOL UAVs (RC Helicopters)
Sailing and Sailboat Design

If there is one or more of these topics that you are specifically interested in please also let me know in your comments this will help me to write blog articles that are more helpful.

References:

[1] https://solarfilm.co.uk/

[2] https://deluxematerials.co.uk/

Disclaimer: Eiteog makes every effort to provide information which is as accurate as possible. Eiteog will not be responsible for any liability, loss or risk incurred as a result of the use and application of information on its website or in its products. None of the information on Eiteog's website or in its products supersedes any information contained in documents or procedures issued by relevant aviation authorities, manufacturers, flight schools or the operators of aircraft, UAVs.