If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#11
|
|||
|
|||
Why don't wings have dimples?
|
#12
|
|||
|
|||
Why don't wings have dimples?
In article ,
Ron Wanttaja wrote: On 12 Jun 2006 06:07:26 -0700, wrote: if golf balls have dimples, to help them sail further, why don't wings Philippe Vessaire wrote: because birds hav'nt.... Dang. That's a lot of feathers for the fellow to have to glue to his wings. "Fortunately, I keep my feathers numbered for just such an emergency." - Daffy Duck Foghorn Leghorn. Ron Wanttaja |
#13
|
|||
|
|||
Why don't wings have dimples?
Capt. Geoffrey Thorpe wrote: ... Dimples work on round things under a relativly narrow range of reynolds numbers (a function of speed, size and properties of air) by helping keep the boundry layer attached. Golf balls happen to fit into that range and have the right shape. Gliders sometimes use "turbulator" tape to trip a laminar boundry layer and make it turbulant so it will stay attached longer - but the placement is critical (and only works if you have a very laminar wing to begin with). So, if you are having boundry layer seperation problems due to the shape of your fairing aft of the maximum "thickness", then dimples or other boundry layer devices may or may not help but most likely they will not. So maybe you could use dimples on fairings, fuselage or struts, especially if the struts are circular tubing, eh? -- FF Lots of aviation stuff for sale cheap: http://groups.google.com/group/rec.a...e=source&hl=en |
#14
|
|||
|
|||
Why don't wings have dimples?
Dancing Fingers wrote: Hi all, I always wanted to build my own airplane but the time and money has eluded me. So I've decided to design and build my own recumbent trike, with farings. This brings me to my question, if golf balls have dimples, to help them sail further, why don't wings -- especially for STOL aircraft? Would putting dimples in my faring reduce my wind resistance? Just curious. Chris I read a story about NASA research of wings with thousands of tiny holes that suck air into them on the top of the wing. Apparently they aid in laminar flow, but there were concerns with the holes clogging too easily with dirt. Dean |
#15
|
|||
|
|||
Why don't wings have dimples?
wrote in message ups.com... Capt. Geoffrey Thorpe wrote: ... So maybe you could use dimples on fairings, fuselage or struts, especially if the struts are circular tubing, eh? -- FF Could be. Somewhere or another I saw some wind tunnel data on golf balls that nicely showed how the flow remained attached further around the back side (no spin was involved - just a reduction in the wake). But you would have to find out what the range of Reynolds number this works for... -- Geoff The Sea Hawk at Wow Way d0t Com remove spaces and make the obvious substitutions to reply by mail When immigration is outlawed, only outlaws will immigrate. |
#16
|
|||
|
|||
Why don't wings have dimples?
Thanks everyone for the great answers vto my silly question.
Capt. Geoffrey Thorpe wrote: wrote in message ups.com... Capt. Geoffrey Thorpe wrote: ... So maybe you could use dimples on fairings, fuselage or struts, especially if the struts are circular tubing, eh? -- FF Could be. Somewhere or another I saw some wind tunnel data on golf balls that nicely showed how the flow remained attached further around the back side (no spin was involved - just a reduction in the wake). But you would have to find out what the range of Reynolds number this works for... -- Geoff The Sea Hawk at Wow Way d0t Com remove spaces and make the obvious substitutions to reply by mail When immigration is outlawed, only outlaws will immigrate. |
#17
|
|||
|
|||
Why don't wings have dimples?
Does anyone know of a good simulation program where you could play with
dimples on a large hot dog shape, just to see what happens. Just more curious. Chris Dancing Fingers wrote: Thanks everyone for the great answers vto my silly question. Capt. Geoffrey Thorpe wrote: wrote in message ups.com... Capt. Geoffrey Thorpe wrote: ... So maybe you could use dimples on fairings, fuselage or struts, especially if the struts are circular tubing, eh? -- FF Could be. Somewhere or another I saw some wind tunnel data on golf balls that nicely showed how the flow remained attached further around the back side (no spin was involved - just a reduction in the wake). But you would have to find out what the range of Reynolds number this works for... -- Geoff The Sea Hawk at Wow Way d0t Com remove spaces and make the obvious substitutions to reply by mail When immigration is outlawed, only outlaws will immigrate. |
#18
|
|||
|
|||
Why don't wings have dimples?
("Alan Baker" wrote)
First of all, golf balls have dimples because in order to create lift they need to influence the air passing by them with the golf ball's spin. The dimples help to make the air slow down beneath the ball and speed up above it; creating downward flow. Wings produce that downward flow with their shape. How about a dimpled spinner? Your choice - slice or draw. Montblack |
#19
|
|||
|
|||
Why don't wings have dimples?
"Capt. Geoffrey Thorpe" The Sea Hawk at wow way d0t com wrote in message
... wrote in message ups.com... Capt. Geoffrey Thorpe wrote: ... So maybe you could use dimples on fairings, fuselage or struts, especially if the struts are circular tubing, eh? -- FF Could be. Somewhere or another I saw some wind tunnel data on golf balls that nicely showed how the flow remained attached further around the back side (no spin was involved - just a reduction in the wake). But you would have to find out what the range of Reynolds number this works for... -- Geoff The Sea Hawk at Wow Way d0t Com remove spaces and make the obvious substitutions to reply by mail When immigration is outlawed, only outlaws will immigrate. I've seen a video of that, but don't recall where. However, I believe that you have it backward--the flow detaches earlier (from the non-spinning golf ball) and reduces the drag. I am not quite sure how that might relate to wings and propellers; but I suspect that they (wings and props) are two radically different, and possibly opposite, phenomena. Peter |
#20
|
|||
|
|||
Why don't wings have dimples?
"Alan Baker" wrote in message ... In article . com, "Dancing Fingers" wrote: Hi all, I always wanted to build my own airplane but the time and money has eluded me. So I've decided to design and build my own recumbent trike, with farings. This brings me to my question, if golf balls have dimples, to help them sail further, why don't wings -- especially for STOL aircraft? Would putting dimples in my faring reduce my wind resistance? Just curious. Chris First of all, golf balls have dimples because in order to create lift they need to influence the air passing by them with the golf ball's spin. The dimples help to make the air slow down beneath the ball and speed up above it; creating downward flow. I believe that you have the effect exactly backward. The spin, which should only be significant using the more steeply pitched irons; slows the relative speed over the "top" of the ball and causes it to remain attached longer, while the air flowing under the bottom breaks away more quickly, which would result in a slight net lift. It also explains why a "slice" curves as it does--which is why a smooth ball would have improved my game. :-( Wings produce that downward flow with their shape. Exactly. Peter |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
VP-II wings available in Oregon, USA (Or, "How I was coconuted...") | Roberto Waltman | Home Built | 2 | October 29th 04 04:21 PM |
Charging for Wings safety seminar? | Marty Shapiro | Piloting | 19 | June 23rd 04 05:28 PM |
Double covering fabric covered wings | [email protected] | Home Built | 9 | May 9th 04 08:39 PM |
Stolen "Champ" wings located...from 23,000 feet!! | Tom Pappano | Piloting | 17 | December 15th 03 02:24 PM |
Wings from "Champ" stolen in Oklahoma after emergency landing | Tom Pappano | Piloting | 1 | December 7th 03 06:02 AM |