Designing an RC Plane Using a Spreadsheet

If you start trying to design an RC plane, just about everything affects other things.

Say that you are designing a 3D airplane. You have completed most of your design, but then you remember that if you want your plane to be able to climb vertically, you will need a thrust to weight ratio of at least slightly more than one. You decide that you then need a more powerful motor to give you the thrust that you are looking for. This motor happens to weigh an extra 25 grams than the previous one that you were initially planning to use. Assuming that you did not change the weight of the plane, since wing loading = weight / wing area, you have just increased the wing loading. 

Another example is finding out that the wing loading is to high, then you increase the wing area to lower the wing loading and decrease the plane's stall speed. 

However, There is a way to design the best possible RC plane, plus keeping track of all of the changes that are taking place in as many areas of the design as you want. Use a spreadsheet!

They look really boring, but my Dad showed me how useful and fun they could be really recently when we were designing an RC plane (not the foam board one in the about me page). 

This is a copy of the spreadsheet that I made a few days ago.

Blogger does let you enter spreadsheets very easily so you will have to scroll around for a while to see where everything is and what information is there, sorry. Pay most attention to the aspect ratio, wing loading, wing area and weight. Unfortunately, it doesn't allow you to edit. These are the formulas I used. Remember that the boxes that I use in the formulas (e.g L39) change depending on which boxes you actually use for the different values. The brackets are not part of the formulas. You don't have to do it this way, this is just the way I did it. Use whatever units of measurement you like, just remember to be consistent

• Wing Loading : = (weight in grams) i18 / (wing area in sq. dm) K18
• Aspect Ratio: = (length in cm ) K21 / (width or chord in cm) K23
• Weight: = All the parts added up (Engine speed control, motor, battery, airframe, servos) = J32 + J34 + J36 + J38 + J40 (weight in grams if you used grams before)
• Wing Area: = (wingspan in centimetres ) K21 * (multiplied by) K23 (width or chord in centimetres) 

If you decide to design an RC plane and want to use a spreadsheet. Great! Because they are really helpful. Something that I did not do in this version of the spreadsheet that I recommend is putting the units in the boxes below the values because it gets hard to remember after a while.