Some outstanding measurements on drag reduction from the Standard Cirrus NewsGroup that I subscribe to. This is truly remarkable stuff, read on. (Could this be the start of a quantum leap in performance improvement????????)
------- Forwarded message follows ------- Date sent: Mon, 20 Oct 2003 19:31:27 -0500 From: Jim Hendrix <[EMAIL PROTECTED]> Subject: [StandardCirrus] Sinha Flexible Composite Surface Deturbulator To: Standard Cirrus - Yahoo <[EMAIL PROTECTED]> Send reply to: [EMAIL PROTECTED] Some of you in the Standard Cirrus group may not be active readers of the rec.aviation.soaring news group where I made an announcement today. So I thought I would send you the same message. It follows: ---------------------------------------------------------------------- - Subject: Sinha Flexible Composite Surface Deturbulator Well, here goes. I'll understand, or try to anyway, if my friends, who used to think of me as a reasonable, level headed kind of guy, turn and run when they see me coming down the street. Maybe it really didn't happen. Maybe it was only a dream. Maybe it was a calculation error or equipment failure. Maybe someone who really knows how to test aircraft can see a flaw big enough to make it all go away. Maybe I'll just end up with egg on my face and that will be that. But I keep sitting here, looking at this graph, in disbelief. I built the drag rake, constructed and calibrated the pressure sensor, flew the test flights, crunched the numbers, plotted the graphs. I can't just write this off as a kooky claim by someone I never heard of. You have that luxury, not me. Sumon, Dr. Sinha, my long time friend and hydrodynamics professor at Ole Miss, told me a few months ago that he thought we could get 25% profile drag reduction on my Standard Cirrus wing. "Yea, sure," I thought. "We,ll see." He had already demonstrated 18% on an NLF0414F airfoil last year in Starkville, MS. And we easily got the same number at some airspeeds on the first attempt with my glider which has a very different airfoil. "That was about it," I thought. "We lucked into the sweet spot and we probably can't do much better than that." Then, two days ago, last Saturday, October the 18th, Sumon thought he'd try a little modification. I knew before landing that there was some improvement, about 0.12 volts on the pressure sensor at 100 kts and much smaller improvements at low speeds. (With this sensor, 1 volt is 1 inch water gauge pressure.) When I got home and processed the data, there it was. We had essentially doubled the drag reduction we were seeing at speeds over 70 kts and we exceeded 26% improvement at two points, one being the highest tested speed, 100 kts. The average from 50 to 100 kts was 23.7%. We had also corrected a low speed roll off so that we now saw basically flat drag reductions, as a percentage of clean wing values, at all airspeeds from 40 to 100 kts. Maybe it's a fluke, some huge error. Maybe we won't be able to repeat it and that will be that. Or, maybe it's real. For the full details you can take your browser to www.oxaero.com and click the Sinha Deturbulator and Test Results links. So there it is. Don't expect me to defend it. I'm happy to let time be the judge. ... --------------------------------------------------------------------- Observation, there's a lot of life left in the wonderful old birds yet. Regards, ----------------------------------------------- Jim Hendrix 662-234-0492/7508 voice OXFORD AERO EQUIPMENT 662-234-2195 fax 417 N. 11th Street [EMAIL PROTECTED] Oxford, MS 38655 www.oxaero.com ------- End of forwarded message -------ANDREW WRIGHT -- * 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.
