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Old 02-27-2015, 05:59 AM
  #18  
Genslro
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I have to apologize, but my numbers were a little off for a 40% airplane. I was in a hurry and the wing load numbers I used were for 30-33%. The numbers I should have used are 2.0 to 2.5 for aerodynamic (38 to 47.5 lb) and 1.5 to 2.0 for 3D (28.5 to 38). I think that anything less than 26 pounds is going to be just a little squirrely. My guess is that most IMAC planes are set up around 2.2 to 2.3 pounds per square inch and the same planes used for 3D are set up at around 1.75 to 2.0 pounds per square inch. But you are right, 26 to 28 pounds is attainable if you are able to control the design and construction weight and from the sound of it, your airplane flies just fine.

We have a guy from West Virginia that comes to our field every so often and he exclusively flies 3D with 40% IMAC birds and I think his wing loading ranges from 1.8 to 2.0 depending on the airplane. All of his planes are Pilot ARFs that he has modified, but even then he does not have that much control over the basic airframe weight. His planes fly very well.

Like I said before, proper weight is dependent on many factors, not just wing area. The plan form of the wing and the airfoil are very important factors and should be analyzed together to determine proper loading. I primarily use a 15% symmetrical airfoil that I developed on my aerodynamic designs and it generates more lift than the 12 to 13% airfoils used on many ARFs. Therefore my wing loading can be slightly higher with similar performance.