Andrew, I am busy for the next couple of weeks. But you are more than welcome to come over one night after J and I get back from the GCV camp at Khancoban. I can try and answer your questions for you then.
Anthony -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of ANDREW WRIGHT Sent: Wednesday, 22 October 2003 1:29 PM To: [EMAIL PROTECTED] Subject: [aus-soaring] Where is the drag To Mike Borgelt, Anthony Smith or anyone else who knows. I am really confused about this drag thing so please stay with me on this whilst I explain. My confusion surrounds the speed range at which defects in the BOTTOM surface of the wing effect the performance most. Do defects (read extra drag) on the bottom surface of the wing hurt the low speed performance most or the high speed performance most? (As I understand it the top side produces more drag than the bottom side, three times as much at 40 kts, two times at 50 kts and 1.5 times at high speeds.) Mike Borgelt said; > "the bubble is usually smaller on the top surface because to >get one you need a favourable pressure gradient for laminar flow and >low Reynolds numbers. This occurs on the lower surface at low >speeds/high angle of attack. On the top surface the low angle of >attack case occurs at higher speeds where the Reynolds numbers >are higher and hence the bubble doesn't form or is small." Does this mean; 1. That anything that prematurely triggers a bubble on the top surface will be a greater drag penalty than something that prematurely triggers a similar bubble on the bottom surface? 2. That anything that prematurely triggers a bubble on the top surface will effect the high speed performance more than the low speed performance. (Because on the top surface the low angle of attack case occurs at higher speeds where the Reynolds numbers are higher and hence the bubble doesn't normally form or is small.) 3. That anything that prematurely triggers a bubble on the bottom surface will effect the low speed performance more than the high speed performance ( Because a favourable pressure gradient exists for laminar flow and low Reynolds numbers at low speeds/high angle of attack.) I am completely confused !! PS 1. I am very interested in this stuff and really appreciate the benefit of your knowledge. PS 2. Anyone who is bored by this stuff is welcome to hit the delete key at anytime. Regards Andrew Wright (VH GAM) -- * You are subscribed to the aus-soaring mailing list. * To Unsubscribe: send email to [EMAIL PROTECTED] * with "unsubscribe aus-soaring" in the body of the message * or with "help" in the body of the message for more information. -- * You are subscribed to the aus-soaring mailing list. * To Unsubscribe: send email to [EMAIL PROTECTED] * with "unsubscribe aus-soaring" in the body of the message * or with "help" in the body of the message for more information.
