My Yankee Mike RC Plane Design
Thoughts and lessons learned on a first RC plane design
Yankee Mike prototype from RC plane from plans
The Yankee Mike was my very first RC model airplane design, completed and published the July 1998 RC Modeler magazine. The Yankee Mike was built in those pre-electric power days with design parameters ideal for the compact Saito .30 four cycle motor. However, the Yankee Mike was my first foray into the world of RC model plane design, and some useful lessons can be gleaned from my experiences and applied to any RC plane design and plan you might envision today.
A job begun is half done
I am a firm believer in “a job begun is half done.” For any RC airplane design, you simply have to decide to start some sort of concept, and put pencil to paper. Of course, that was back in 1998 before practical CAD programs became available for the home user. But even with today’s CAD programs, you’ll likely start with a model plane design concept sketched on paper.
Buhl Pup aircraft in flight
On a first model plane design, start with something easy. For the Yankee Mike, I took the general lines and layout of the Buhl Pup, a lightweight sport aircraft of the 1930s. I took inspiration from the Buhl Pup’s constant chord wing (just one wing rib to draw out), classic good looks, long enough nose and tail moments for balance, and a strong landing gear arrangement with a bit of character.
I did not do a lot of calculations for the initial dimensions of the Yankee Mike RC plane design. Rather, I emulated the proportions of the Buhl Pup, and I sketched out an initial plan that looked about right. The model came out surprisingly well given the lack of rigorous aerodynamic analysis. The only thing I should have done different was to make the wing chord slightly wider, for greater wing area. The Yankee Mike also came out just a bit heavier than I would have liked.
Yankee Mike article in 1998 RCM magazine
Use existing structural designs
For the Yankee Mike’s RC plane design internal structure, I used tried and true fuselage and wing spar construction techniques from other model aircraft I had built and flown. The only thing I did slightly different, and you’ll see this throughout my designs, is to add a bit of plywood around the forward fuselage and nose section for strength. While strength is a good thing, keep in mind you are also adding weight to your RC plane design. As always, you have to carefully balance the need for extra strength vs. the penalty of extra weight on flight performance.
The more I build and design, I have come to the conclusion that a lot of the extra structure I added to various designs was not really needed for safe flight of the RC model plane. So now, with more experience, I am leaving off structural pieces I might have added before. Remember, a lighter model will always fly better than a heavier one.
Determine aircraft design parameters
Please check here for a discussion of how to compute the various wing and tail areas and moments for a typical RC plane design. While there is no firm rule on how to do this, once you find a control and area arrangement that works (either from your own design or another kit or plan), go ahead and continue to use these parameters. You will find as you fly your designs that you will gain an intuitive sense of how much control throw you need, etc. In addition, when deciding the amount of tail or wing area, it is just about always safer to make the flight surfaces larger if in doubt.
Final Yankee Mike hand drawn plan from July 1998 RC Modeler magazine
The center of gravity is an absolutely central requirement for the safe flight of any RC plane design. For a straight, constant chord wing, you can start with the CG about 30% back from the wing’s leading edge. Again, if in doubt, move the CG slightly forward (add nose weight). You can survive an RC plane design's initial flight with a slightly forward CG rather than one a bit too far aft. Any model with an aft center of gravity will have an uncontrollable series of pitch ups usually leading to a crash.
Final version of Yankee Mike RC plane
Inspect after first flights!
With any original RC plane design, to include the Yankee Mike, perform a careful inspection of the aircraft after your first flights. You will be surprised at what little cracks and structural separations you will find as you examine the airframe. Again, this is all part of the RC plane design process. Take these signs as various “lessons learned” for your future RC plane designs, where you might have to add a strengthening gusset, or use a slightly stronger or larger type of balsa wood.
Yankee Mike | RC Plane Design