It is an age old saying in the vast subject of design, that design in its most inherent form is always a delicate balance of various compromises, and RC model aeroplane design is no exception. In the video below, I discuss some things I personally find helpful to take into account, when designing radio controlled model aeroplanes.
A trend you will perhaps notice with these design considerations, is that they tie in closely with the purpose of the aeroplane itself. This will be explained over the course of this article and the video.
Things to consider when designing the forward fuselage of a radio controlled model plane:
1. Fuselage width/cross section dimensions. This ties in most closely with the overall function you wish your model to have. If you wish to design a high speed pylon racer or a super efficient slope soarer, then keep your fuselage diameter to the absolute minimum dimensions that practicalities ( such as required battery space) dictate.
Take my recently built Flite Test Tiny Trainer chuck glider. As it can be build as a unpowered radio controlled glider ( this example is free flight ) note the narrow dimensions of the fuselage, in relation to the wing and tail area. This reduces the overall form drag ( air resistance caused by the bulk of the model travelling through a medium, in this case air), and therefor increases overall aerodynamic performance ( such as top speed and gliding efficiency) as a result.
A small fuselage cross section, is also featured in full scale designs, where speed or gliding efficiency is of primary concern. Just look at any fighter plane or glider from history ( or the present day) to see this.
Both of these designs ( a Spitfire and Swift glider respectively) , had both very different functions ( the Spitfire being a WW2 era fighter aeroplane, and the Swift being a modern day pleasure glider) , but both feature extremely narrow fuselage cross sections, to give speed and aerodynamic efficiency.
By contrast, a design, full scale or model, where speed and aerodynamic performence is not a primary deisgn goal, a wide diameter fuselage is used. A great example of this in the model world, is the Flite Test Guinea Pig design.
From even a quick glance at the model, it is clear that speed was not really a primary design consideration for this model. The key goal was the ability to carry copious amounts of equipment, such as candy, cameras and even other aeroplanes! Remember the Pun Jet?
To use my own design as an example, I chose a rather wide diameter fuselage, as speed for me was not really important for this model. I was more concerned with being able to mount a lagre volume of batteries and FPV equipment in the confines of my fuselage design.
2. Covering material. This aspect is especially important for foamboard aeroplanes, as exposed white foamboard is quite vulnerable to damage when exposed to moisture. For my design, the covering material is of great importance, as the plan is to have the plane land on its belly when complete.
I go into the various choices in the video in much greater depth, but I chose yellow duct tape. Despite this material being a little heavier than packing tape, it is far more robust, with woven cotton fabric in the substance of the tape itself.
As you can see from the picture, I also chose yellow for a very practical reason. Yellow really stands out from the rest of the picture, quite distinctively, as you can see. This will make orientation in the air extremely easy, even in overcast conditions.
I hope you found this article and video of my creation helpful in coming up with a forward fuselage design for your own builds. Obviously, there is a lot more things to take into account, but to keep the article and video engaging, I mainly focused on the design considerations which I think have the most importance for new designers and builders.
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Image credits: Spitfire: By Adrian Pingstone (Arpingstone) - Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=4476784
Swift Glider: By Adrian Pingstone (User:Arpingstone) - Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=7929713
Ft Guinea Pig: Property of the Flite Test website
All other images in this article are my own work.