>-----Original Message----- >From: Stuart A. Hall [mailto:[EMAIL PROTECTED] > >If you check out the various ads and articles in Model Aviation and on >the Web you will notice how many of them refer to "Drela airfols".
If the writer of the ads and articles didn't say what the airfoil was then almost everyone reading the ad or article would be left wondering what the airfoil was. There really is no mystery here. The airfoil is almost the first thing that anybody wants to know about a plane. If this information were not supplied in the ad or article then someone would be spending a lot of time answering individual emails or phone calls to answer that question. >It is >true that the Bubble Dancer, Allegro and other assorted planes fly quite >nicely, but I wonder how much of the airfoil choice is just a marketing >gimmick. The manufacturer of a new plane will use whatever airfoil he/she thinks will do the best job on the airplane he is building. A very great many modelers have come to believe that Drela airfoils are the best airfoils available. Why would they not choose those airfoils for their models? A marketing gimmick would involve advertising something to your customers that sounds really good but is in fact inferior but easier/less expensive to produce. Drela airfoils are the opposite of that. They are widely held by the modeling public as the best performing airfoils. They are also known by model manufacturers to be far more difficult and expensive to produce. This due to their thinness which requires more expensive materials and more labor to build. >One extra swipe of the sandpaper by our Czech worker-bee has >turned that Drela foiled AVA/Topaz/whatever into some other airfoil. There are inaccuracies involved in the production of any airfoil. This is true no matter what airfoil is chosen or which building method is used. Why not choose the best airfoil available and do your best to make it as accurate as you can? >Particularly on these amazing built up RES ships with mylar covering, I >wonder how much of the performance is due to the airfoil and how much is >due to very light balsa/composite building techniques. Dr Drela designs his airfoils for each specific application. In the case of a film covered wing, The wing/airfoil is designed such that all areas which are to be film covered will have flat facets rather than a curved airfoil shape. Since the airfoil was designed with this in mind, very little performance is sacrificed compared to just using a locally curved airfoil and letting the film covering sag between the ribs. >Does Dr. Drela get a royalty for the use of his name in advertising? >Did/does Dr. Selig? I sincerely doubt that this ever happens. Dr Drela freely publishes all of his airfoils and model plans and spends many hours at the computer instructing people on many topics. Every detail of his model plans have been discussed in public forums. Dr. Drela freely discusses the smallest detail of construction. He also freely shares his remarkable aerodynamic knowledge in a number of different groups. To even suggest a profit motive for all of Dr Drela's contributions to this hobby is way off base. Phil RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off.
