Mike Selig was visiting Denver a few years ago and was a guest speaker at our monthly RMSA club meeting. I was building a Saturn 2.9T at the time, and was wondering if there was anything special I could do with the wing tips to help performance. So I asked Mike about this and his response was that a sharp square tip was pretty close to optimal - but not quite as good as a well designed optimal tip. He added that the square tip is MUCH better than a poorly designed tip - such as an improper winglet or drooped tip. The Saturn flew great - with squared tips. I've never forgotten this advice.
Mark -----Original Message----- From: bcourtice [mailto:[EMAIL PROTECTED]] Sent: Wednesday, January 23, 2002 2:20 PM To: [EMAIL PROTECTED] Subject: [RCSE] wing tips: a peculiar experience I have an original design slope plane with a single taper rg-14 wing that originally had a tip design that rounded back from the leading edge to end at a point on the trailing edge, very much like what you typically see on a lot of electric hotliner type planes these days. The airplane flew fine in a good wind, but in lighter winds it was a disaster. It would tip stall violently, and recovery would often just lead to another stall. Well, the tip stall behavior resulted in a crash one day that ended up taking off one wing tip completely. (The tip was attached to the end of a foam core wing that had a square outboard edge.) I decided right then and there to deliberately remove the other wing tip right at the field. I now had a wing with plain square tips. I tossed it back out and the tip stall was completely cured! Back at the shop I attached small squared of wood tips to protect the exposed foam at the ends of the wings. I did bevel these tips so that the top span of the wing tip was about 1/4 inch greater than the bottom span. I have read somewhere that this kind of beveled tip is more efficient drag wise than a straight up and down tip. Anyway, the plane is now a joy to fly, and even on those days when the winds are light and you have to "milk it" to keep the airplane flying, it shows no bad habits whatsoever. I guess the moral of the story is that there may be more important considerations when designing a wing tip than just reducing drag. A draggy wing that keeps flying is better than a wing that very efficiently keeps falling out of the sky!! :) --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.317 / Virus Database: 176 - Release Date: 1/21/2002 RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] ******************************************************************************** This message is intended only for the use of the Addressee and may contain information that is PRIVILEGED and CONFIDENTIAL. If you are not the intended recipient, you are hereby notified that any dissemination of this communication is strictly prohibited. If you have received this communication in error, please erase all copies of the message and its attachments and notify Space Imaging immediately. ******************************************************************************** RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
