Jim & Netters: Looks like some of this can apply to an aircraft as well under the right circumstances! Correct?
Don ------------------------------------------------------------------------ Jim Payne wrote: > Actually, lift only comes into play when the ball is spinning. The reason a > golf ball flies farther with dimples is because a golf ball is not > aerodynamic. The air traveling around a smooth golf ball is traveling very > fast close to the surface of the ball and the air will separate abruptly > past the vertical center of the ball creating a large air void at the rear > of the ball of drag slowing the ball down. The dimples are added to create > turbulence near the surface of the ball allowing the air to decelerate > around the ball so the air can follow the contour of the ball longer, > reducing the cone of drag behind it. > > A smooth surface will be faster than a rough surface if the air is able to > follow the contour of the surface. Once the air cannot follow the surface, a > result of speed and shape, then creating a turbulent surface will be > beneficial. You get more surface drag from a rough surface but you can > reduce the pressure drag trailing the object that is much greater drag. > > A rough suface creates turbulence and decelerates air around the boundary > layer delaying it's separation from the object, reducing it's trailing drag. > > Jim > > -----Original Message----- > From: krnet-boun...@mylist.net [mailto:krnet-boun...@mylist.net] On Behalf > Of Mark Jones > Sent: Thursday, April 13, 2006 7:09 AM > To: KRnet > Subject: Re: KR> Armoural > > The dimples on a golf ball are there for the purpose of lift which keeps the > ball in the air longer. At least this is what I have always read. A golf > ball with no dimples simply will not travel nearly as far as a dimples one > because it has no lift. Haven't you guys seen the dimpled leading edge tape > you can get for wings and props? It gives the wings more lift at slow speeds > which keeps the air from breaking off the wing pre stall. On the prop, it > gives it more bite. At least that is what I read. > > Mark Jones (N886MJ) > Wales, WI USA > E-mail me at flyk...@wi.rr.com > Visit my NEW > KR-2S CorvAIRCRAFT web site at www.flykr2s.com > > ----- Original Message ----- > From: "D F Lively" <riksh...@interl.net> > To: "KRnet" <kr...@mylist.net> > Sent: Thursday, April 13, 2006 7:02 AM > Subject: Re: KR> Armoural > > > KRnetters: > > > > This sounds analogous to the reason golf balls are "Dimpled". > > > > Don Lively > > ------------------------------------------------------------------------ > > > > "Hennie van Rooyen [HQP]" wrote: > > > > > Hi all, > > > > > > Just my 2 cents on this subject. There's a lot of info on the net on > this so I'll not even try to elaborate. > > > > > > Air over air causes a lot less friction than air over metal, fiber glass > or whatever. Therefore a very slight rough surface on i.e. a wing (pinholes) > will produce less friction than a very smooth wing surface and therefore > also higher top speed. > > > > > > You actually want dull surfaces for more speed as bright smooth surfaces > are purely for appeal and not for speed. The air clings to the surface and > this is the exact opposite of what you want. > > > > > > I'm convinced that if you take sandpaper and apply to your KR giving it > a dull, non shiny surface (not nice to look at), you'll get the speed > increase you're after. > > > > > > Regards, > > > Hennie > > > > > > -----Original Message----- > > > From: krnet-boun...@mylist.net [mailto:krnet-boun...@mylist.net]On > > > Behalf Of Frank Ross > > > Sent: Thursday, April 13, 2006 10:13 AM > > > To: KRnet > > > Subject: RE: KR> Armoural > > > > > > I know there aren't many things funnier than putting a good coat of > Armor All on the seat of a dirt-bike right before a steep hill-climb and > watching the rider try to stay on the seat... > > > > > > > > > Brian Kraut <brian.kr...@engalt.com> wrote: Did you scrape an inch of > bugs off the leading edge before you put that > > > Armor All on? > > > > > > I do know that fiberglass gliders fly considerably better when they are > > > clean and waxed, but they have a whole lot more wetted area than a KR > and > > > competition gliders likely have much more critical airfoils than the KR > > > does. > > > > > > Brian Kraut > > > Engineering Alternatives, Inc. > > > www.engalt.com > > > > > > > > > --------------------------------- > > > How low will we go? Check out Yahoo! Messenger's low PC-to-Phone call > rates. > > > _______________________________________ > > > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > > > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > > > please see other KRnet info at http://www.krnet.org/info.html > > > > > > > -------------------------------------------------------------------------- > --------------- > > > This e-mail is confidential and is for the addressee only. > > > Please refer to http://www.kumbaresources.com/email-disclaimer for > important disclaimers. > > > > -------------------------------------------------------------------------- > --------------- > > > > > > _______________________________________ > > > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > > > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > > > please see other KRnet info at http://www.krnet.org/info.html > > _______________________________________ > > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > > please see other KRnet info at http://www.krnet.org/info.html > > > > _______________________________________ > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > please see other KRnet info at http://www.krnet.org/info.html > > _______________________________________ > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > please see other KRnet info at http://www.krnet.org/info.html
