In a prior thread, Abufletcher made a comment that set me to thinking. Here's what he said:


"I, for one, don't want a model that flies BETTER than the original. I don't want a RE-ENGINEERED version. I'll never fly a full-scale replica...the closest I'll ever get is a scale-flying miniature. And if the original had adverse yaw, then I want to experience what it was like to fly with adverse yaw (and "a boot full of rudder")."


I'm sure many of us share Don's sentiment. But, does ANY scale model really fly like its full sized counterpart ? I think the answer is a resounding NO !

Just because a scale model is shaped exactly as the full size plane was shaped, right down to the original airfoil, there are several reasons why the model doesn't really fly the same as the full scale. Unfortunately, most modelers have never seen the full scale version fly. Or at least seen enough flying to study the behavior of the full scale.

Why aren't they the same ? Well, there are several reasons. The first that comes to mind is the vastly reduced mass (inertia, if you will). When a 1500 lb. airplane hits a gust, it reacts much more slowly and with less motion than does a 6 lb. model. The result is quick little motions with far greater amplitude than the full size version. That's why scale models look so much more "real" on a calm, smooth day.

Then there's the takeoff and landing problem. The full scale WWI planes were directionally unstable on takeoff and landing roll. We know that. But the pilots were usually able to overcome the instability because the swerves happened so much more slowly. On models, the swerve and flip over onto the top wing can happen so quickly that we sometimes only let out a gasp when it's all over. Again, lack of inertia.

Then there's the problem of how rapidly the model reacts to control inputs. With such low inertia, a model reacts very rapidly. Rolling and pitching motions look far slower and smoother on the full scale machines.

As models are made larger and larger, they approach the behavior of the full scale plane. With their greater mass and inertia, they respond more slowly and gracefully to pilot inputs and gusts. That's one of the reasons why giant scale planes are so popular. But most of us want to have smaller scale models with their correspondingly smaller costs, storage, and transportation problems.

So, my question for this thread is: What can we do to make our scale models give us "the closest experience in a scale-flying miniature" ? (Loose quote from Abufletcher)

Dick