donpearsall
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Age: 59
Location: Seattle Area
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« Reply #15 on: October 22, 2009, 11:21:23 AM » |
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The testing that Popular Mechanics did with FastSkinz and what Mythbusters did was different. FastSkinz has very shallow depressions about 5mm in diameter (very small). The Mythbuster car had big depressions about the 3" in diameter and 1" deep. The Mythbuster dimples were supposed to be on the same scale as a golf ball while the Fastskinz are not. I think that the FastSkinz dimples are not big enough to detach the laminar flow while the big dimples on the Mythbuster car do detach the flow. Fastskinz only real-world claim was that Leslie Porterfield said that she gained 3mph with FastSkinz on her bike. That's just not a good test. Too many variables.
Don
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550 hp 2003 Suzuki Hayabusa Land Speed Racer
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joea
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« Reply #16 on: October 22, 2009, 11:31:53 AM » |
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re an earlier post about leslie porterfield..perhaps using it....
i looked closely at her bodywork...and there were
no dimples..especially on the critical "tail section" area....
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Warp12
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« Reply #17 on: October 22, 2009, 11:44:52 AM » |
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I didn't see the episode, but I was wondering if the car was made to weigh the same before and after "dimpling"? Were the climate and other environmental factors indentical during before and after testing?
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John Noonan
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Age: 45
Location: 6 X 200 club member: El Mirage 2 Club, Bonneville 2 Club, Australia 2 Club, Maxton, 2 Club, Mojave 2 Club, Bubs 201 Club
Posts: 3266
245 200+ mph time slips. 252 mph on a dirtbike
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« Reply #18 on: October 22, 2009, 11:49:26 AM » |
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I have looked and felt her tail section and she has little bumps... The bodywork guys...the bodywork..  I saw it a few times on her bike at Bonneville however I can't say I am a believer however she is the fastest female rider on the salt.  J |
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On 9-27-08 we lost a great friend and fellow racer, he was the BEST, he helped anyone with anything at anytime. His name is Dave Owen and he will be missed by all that knew him and I am glad to have met him.
Seeing him at Bonneville during 2008 Speedweek was the tops, Dave was in awe of the salt and as usual was there helping out anyone who asked..simply put we lost a great man who will be missed by all.
J
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754
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Location: KElowNA B.C. Canada EH!
Posts: 179
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« Reply #19 on: October 22, 2009, 11:58:25 AM » |
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I saw the Dimpled bodywork in the Porterfield Pits at speedweek.. cant say if she ran it..
..nice Pit area BTW.. totaly adequate...
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landsendlynda
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Location: FOUR! Count 'em 4 miles from the salt!!! Life is Goood!
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« Reply #20 on: October 22, 2009, 12:00:39 PM » |
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John, Did Leslie know you were feeling her tail section? Did you have permission? Did she slap yer hand away, or did she just roar off in a cloud of salt? Yeah, I'm talkin' about the bike too!  Lynda |
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Volunteer roadblock at Land's End! Yes, you need your stinkin badge! I'm your Dream Keeper, I protect your dream on the asphalt so you can chase your dream on the salt!
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maguromic
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« Reply #21 on: October 22, 2009, 12:05:45 PM » |
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 .............and the other extreme..... Its a slow day at work. Tony 
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“If you haven’t seen the future, you are not going fast enough”
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Stainless1
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Robert W. P. "Stainless" Steele Wichita, Kansas
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« Reply #22 on: October 22, 2009, 01:30:33 PM » |
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Now our secret is out.... we got an extra several MPH out of the bike after I painted it....  Bob, what size roller do you use? And -- most important -- is it one of those textured ones, like for fiiling the cracks in the pavement with extra ceement? How do you get that nice finish?
SSS, I sprayed it, my painting techniques and proficiency are well known among the Florida crowd... I used to paint their fruit until it evolved into its present state... I don't need no stinkin roller to apply texture..... |
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Stainless
MSA Lakester #1000 my fastest mile 245 and change, 84 ci turbobusa motor... but Corey's H/BFL record is still 3MPH faster than mine.
Builder of Bike 278 1000cc APS-G, Kids Red Hat Record 208.959 (old PS rules)
Other kids A-G record 179.172 Josh O record 182.266
Co-owner of the Amo Steele Streamliner, #1411... still sorting
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fredvance
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« Reply #23 on: October 22, 2009, 01:37:06 PM » |
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1.7 tip for finish coat = grapefruit peel. Fred |
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WORLDS FASTEST PRODUCTION MOTORCYCLE 213.470
Vance&Forstall Racing
All 9 SCTA 1350 NA records
WOS 2011 235+MPH
Engine by Knecum, Tuned by Johnny Cheese.
Sponsers Catalyst Composites, Johnny Cheese Perf, Knecum Racing Engines, Murray Headers, Carpenter Racing
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sockjohn
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« Reply #24 on: October 22, 2009, 02:13:33 PM » |
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I've always thought of Mythbusters as pseudo scientific, they do a decent job but to much gets skipped due to time lines and budget. It doesn't take a genius to figure out where to put the dimples on a golf ball, but where do you put them on a car? Is "everywhere" the optimum solution or do you only put them where the flow is about to separate? It's things like this that I wish they would delve into, and that is what I would consider a rigorous scientific experiment. IMHO this is also the issue with the Flexskinz, unless they have made up an installation guide for each and every car based on wind tunnel testing, it won't work for every vehicle and would be easy to cherry pick a data point and claim x % improvement. A round ball is a pretty far from optimal shape, but would dimpling a streamlined body (i.e., an airfoil body of revolution) have the same improvements or any improvement at all? I would bet dollars to donuts that myself and many others on this site could use that same amount of clay and make LARGER improvements without using dimples. Most of the LSR classes are either very restrictive on body mods like production, or are practically wide open like the streamliner classes. Just because you could use dimples doesn't make it the "best" solution. I have to add, I didn't expect it to work! PS I don't get hangovers, and I own a Harbor Freight ball peen hammer if needed |
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joea
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« Reply #25 on: October 22, 2009, 03:38:31 PM » |
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.........i guess folks who deal with airflow for a living...arent good
authorities on this.......if myth busters guys are your aero expertise...you
get what you deserve.....
as my good friend porkpie pointed out.......are you ready, this is
REALLY complex........hit a golf ball without dimples....then
hit a standard one with dimples......you need nasa to find one of them.....
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Milwaukee Midget
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#996 I/GT
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« Reply #26 on: October 22, 2009, 05:10:54 PM » |
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I remain skeptical - The dimples on a car would remain static with respect to their trajectory.
A golf ball spins and twirls in flight - traits many people try to avoid in their LSR cars.
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Celebrating 50 years of the MGB by desperately trying to keep one roadworthy.
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Dr Goggles
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The Jarman-Stewart "Spirit of Sunshine" Bellytank
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« Reply #27 on: October 22, 2009, 05:19:11 PM » |
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Perhaps you would be better served with the investmant in a ball pein hammer at Harbor Freight. If things work out for you the next step might be improved fuel mileage on your daily driver. Wayno
.........just to back my claim that this ain't new I bring you the DLRA site from a few years back.... Dr Goggles Joined: 05 Jul 2005 Posts: 755 Location: Right behind you Chief ! Posted: Fri Aug 10, 2007 1:46 pm Post subject: Cute dimples -------------------------------------------------------------------------------- Lynchy wrote: Here's a question for the Aero literati: Will the hail damage act the same as the dimpling on a golf ball and promote the laminar adhesion of air over the body thereby allowing an increased speed? Is this cheating or Act of God? Lynchy Dunno Lynchy but I'm gonna bring a little ball-pein hammer to the lake next year in case it catches on , I hereby offer my services to "aero-dimple" any car for a cold six pack. _________________ ...few understand what I'm trying to do , but they vastly outnumber those who understand why.. anyway, long time no see Wayno.... |
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jimmy six
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« Reply #28 on: October 22, 2009, 07:36:06 PM » |
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Look up www.dimpletape.com and see for yourself. I don't think it would go over well on the back edge of tha roadster grille shell with Dan.. But maybe on the front edge of your trailer would be good.......JD |
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First GMC 6 powered Fuel roadster over 200, with 2 red hats. Pit crew for Patrick Tone's Super Stock #49 Camaro
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askotto
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« Reply #29 on: October 22, 2009, 08:26:37 PM » |
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Great to see the sceptics haven't left! What a bunch of non believers. What will it take? When the mythbusters did the test, the cars did weigh the same as they collected all the golf ball "divots" and put them in a can in the back seat. The test was on the same stretch of road the same day. Close enough for me. The clay idea was not to reshape the car for better streamlining, it was just to test the difference between a smooth finish and one with dimples. The Airforce is using this technology but because of the extreme speeds, "shark skin" is all that is needed. Reduces drag and surface temperature. A golf ball doesn't have to spin to get the benefit from the dimples. If your golf ball is spinning, it's probably sailing out of bounds in a slice or hook. They had an expert golfer hit a bunch of dimpled and smooth finish golf balls and the dimpled ones flew almost twice the distance of the smooth balls and the dimpled balls flew straighter. I don't think the entire body needs dimples and some areas may benefit from different size dimples in different patterns. Possibly for a car body going in a straight direction, ridges may be better than dimples. F1 uses "wicker strips" to control laminar flow over their wings. Knowing what I do about airflow, a vehicle with the correct size and location of dimples, ridges or wicker strips will go faster than a car with a smooth finish. Breaking up the laminar flow can reduce drag and that equates to speed. From the sounds of some of the comments, you wouldn't believe dimples would work even if a car did go faster. Some of you really need to loosen up and see the positive side of things. Your negativity is getting you nowhere but more depressed!
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