I'm wondering how to best scratch build an rc aircraft and what rough proportions the aircraft should be in.

I'm aware of the fineness ratio that determines the width to length ratio of a cross section of a wing should be around 1:3 or 1:4, but I can't seem to find similar rules for:

  1. The distance between the wing and tailplane

  2. The length of the wings

Am I just better off just making a scale model of an established aircraft instead of using these rules?

  • 5
    $\begingroup$ The question is likely too broad. I'd say find a good book or two on R/C airplane design. Stay away from scale to begin with; the proportions don't scale down to R/C that well. $\endgroup$ – Fred Larson Jan 16 '20 at 17:37
  • $\begingroup$ You could improve this question by providing more focus. Do you want your aircraft to do acrobatics or be a basic trainer, go supersonic or incredibly slow? What kind of materials do you want to build with? $\endgroup$ – Mark Jones Jr. Jan 16 '20 at 17:44
  • $\begingroup$ @Krish the rule of thumb is to use your brain. Start with the application and work back to your design. Speed is a very critical starting point. Straight wings are best for slower flight. A longer fuselage makes it more stable. Read up on gliders, and aircraft in general. $\endgroup$ – Robert DiGiovanni Jan 17 '20 at 10:29
  • $\begingroup$ This is another question that would be better on area51.stackexchange.com/proposals/123448/… $\endgroup$ – Robin Bennett Jan 17 '20 at 14:02

No, there isn't any single rule of thumb for airframe shape. Just look at the huge variety of airframes that have been built and flown over the years.

One way to scratch-build is to start with a cardboard glider that's roughly the shape you want. Tape the wings and tail to the fuselage in different places, tape on some noseweight, give it a toss, deflect the elevator, give it another toss, vary the dihedral, sweep, decalage.


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