There is something to be said for designing something from scratch, be it a simple free flight model or complex scale warbird. To take a concept from your mind and transform it into reality, is a fantastic journey of self discovery and learning. To give my experience as an example, on the 15th April 2017, I decided to finally start work on my own design, the Eala Emma. This model is primarily designed for FPV and slope soaring as a moterglider, with its twin pusher motors shut down. However due to the capacious and long fuselage, I designed the model to do a whole lot more, which I'll share here on Flite Test.
Photos of the Emma:
1. Overview of the design ( first preliminary sketch)
2. Fuselage completed as of 12th November 2017 ( with Beauty and the Beast pop vinyls for scale)
3. Wings folded ( the design has a folding wing to aid with transportation and storage ) , with omnipresent Belle!
4. Recently cut tail feathers
However, to design this model, I did not just start drawing the plans from my head, without first thinking about my three steps for making a model that I can honestly be pleased with, described in the video below.
With regards to the third tip I gave, if you are designing your model primarily from a full scale aeroplane, you can alter some characteristics when drawing your design to make it more suitable for a model. For example, the Junkers F13, which i based my Gannet cargo plane off, has a rather short nose, as can be seen from this picture.
This may cause some issues with getting the correct centre of gravity on a model strongly inspired by the Junkers F13. In the full size the weight of the engine (the heaviest component in the aeroplane) dictated that the designers use a short nose, as a long nose would more the c.g to far forward. This would make the aeroplane nose heavy, leading to sluggish pitch control inputs, as well as excessive amounts of up elevator to be given just to maintain level flight. With a J13 inspired model, this short nose is more of a hindrance than a help. With brushless motors being lighter, in terms of the motor weight being taken as a percentage of the airframe's total weight, the nose of the plane is lighter overall. This could potentially lead to a tail heavy aeroplane, not a characteristic you want to have on any design. As Josh Bixler says: "A nose heavy plane flies badly, a tail heavy plane flies once".
As a result, I made the nose of my Gannet design slightly longer than the F13's to ensure no c.g issues.
Thank you for taking the time to read this article. Please give this article a rating and comment on any improvements I could make. In addition to this check out my Youtube channel to see more design related projects about model aeroplanes ( and other stuff as well!).
Wishing you fun flying, Finn.