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Master EcoModder
Join Date: Jan 2008
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[aero-mods(aft-body streamlining/boat-tails)Part-3 History/Timeline cont'd
My notes are so scattered,I left out some points I meant to include leading up the 20th-Century.Forgive me for the digression here.
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1858,Hemholtz Theorem#1 published,dealing with vortex behavior,trailing vortex and turbulent wakes ( our enemy ).Sailors refer to these phenomena as:"back wind","wind shadow" and "dirty wind."
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1865,J.Scott Russell publishes observations of "friction belt," laminar boundary layer against sailing ship hulls,The modern System of Naval Architecture,London.
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1877,Osborne Reynolds publishes research on fluid cohesion/adhesion/surface-tension,coining"cappilarity."
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1883,Osborne Reynolds publishes research on laminar and turbulent flow,with trigger-point velocities ( critical Reynolds Number ).
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1897,Frederick W.Lanchester submits paper to Physical Society of London,discussing concept of wing-tip vortices and circulation flow in three-dimensions around an "aerofoil" ( his term ).He introduces the concept of "end-plates",as used today on spoilers.His paper is rejected by the Society's referees.
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1898,gasoline automobiles hit the streets of Europe and USA with Daimler-Benz and Duyrea Brothers cars.The car race is on!
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1900,Count Ferdinand von Zeppelin begins his life's work on airships at Lake Constance.
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1901,Spindletop,oil-gusher well comes in near Beaumont,Texas,USA.Oil is $0.90 a barrel.
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Wright Brothers take to the air at 30-mph (48-km/h) at Kittyhawk,N.Carolina,USA.Heavier-than-air,powered aviation begins international aerodynamic and materials technological innovation.
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1906,Stanley Brother's canoe-bodied steam racer sets land speed record of 127.66-mph ( 205.9 km/h) at Ormond Beach,Florida.
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1907,Frederick W.Lanchester self-publishes his book"Aerodynamics,"in which he develops concept of finite aerofoil.
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Alexander G. Eiffel publishes his aerodynamic research from the "Tower."
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1910,Eiffel publishes his research from new wind tunnel,"Resistance Of The Air And Aviation." Eiffel's study reveals that Paris' ice-cream cone,with 20-degree cone,has lowest drag of any shape tested.By adding the boat-tail cone to the convex-hemispherical forebody,drag is reduced 73-percent.Also,when tests were conducted on Maurice Farman Strut#3,this configuration showed the least resistance of struts tested,and drag declined as velocity increased.Eiffel was witnessing the struts transition from laminar to turbulent boundary layer flow,however would know nothing of such things until Prandtl in the 1920s.In addition,the Farman #3 Strut is close to the 2.5:1 fineness ratio "ideal" teardrop form,as later reported by Hoerner.
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Deperdussin monoplane,first plywood, monocoque- fuselage,with 14-degree angle boat-tail,is first plane to break 100-mph (161 km/h ) speed.
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Edwin Gaulledet one-ups Deperdussin with his Gaulledet "Bullet",very streamlined,pusher-prop,monoplane,pushing speed record to 130-mph (209 km/h ).Aerodynamic "Experts" witness the event in utter dis-belief.Gaullaudet had been considered a misfit looney.His work has evolved into the General Dynamics Corporation,who's products ply the skies overhead,and deep under sea with their nuclear subs.
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1913,Alfa Romeo completes Count Mario Ricotti's-commissioned "wind-deceiver",airship- inspired,one-of-a-kind minivan,with full aftbody and 3.10:1 fineness ratio.Under carriage sucks,and there were no super highways to drive it on,however it did achieve 85-mph (137 km/h ),pretty impressive for the day.Sorry,no mpg figures.
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1914,World War-I begins with assassination of Archduke Ferdinand,Sarajevo.Arms race escalates for duration.
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Race car driver Barney Oldfield pilots Harry Miller's aerodynamic "Golden Submarine",sweeping every dirt track record in the USA.The media had panned the car,making disparaging remarks about it's looks until it began winning.( sounds like Toyota Nation).
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1918,WW-I hostilities end.Germany,Paul Jaray turns from Zeppelin R&D to automobiles.
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1920,Dornier-Werke GmbH ( formerly,Zeppelin Werk Lindan GmbH ) publishes research on truncated aerofoil sections( this will enter into the mythology of truncated boat-tails,and "phantom-tails".As reported in Hoerner's work,Dornier found that 10-percent of the chord ,at the trailing edge could be chopped off,without significant drag increase( 10-percent only!).
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1921,Edmund Rumpler introduces his "teardrop" car ( later tested at full-scale in VW Tunnel,with Cd 0.28 ).The car has full boat-tail when viewed in plan (from overhead).
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1922,Klemperer publishes his research done at the behest of Paul Jaray.Jaray's pumpkin seed car scores Cd 0.13,and Klemperer's "minivan" scores Cd0.15.The Jaray "small car" model,with real world features scores Cd0.28 ( later re-verified in a better tunnel at Cd0.245 )
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1923,Prandtl originates concept of viscous flow boundary layers which explains d' Alembert's Paradox of 1768.
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1923, Prandtl and Klemperer co-develop "mirror image" system for ground plane simulation in wind tunnels.[This is EXTREMELY IMPORTANT TO ECOMODDERS!!!!!!!!!!!!.As far as the air is concerned,your car is TWICE as tall as you think it is!]
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1927,Charles Lindberg's trans-Atlantic flight in aero-optimized Ryan Flyer"Spirit of St.Louis".The Ryan fuselage incorporates a 10-degree-angle boat-tail.Vertical stabilizer area is reduced to cut drag,make the "Spirit" highly unstable in yaw,so as to keep Lindberg awake and busy at the stick for the flight duration.Fuselage drag coefficient is Cd0.27 ( high due to sharp edges ),requires 26.6 horsepower to propel at 100-mph ( 161 km/h ).Also,fabric covers on front wheels cut drag enough to extend flight range by seven miles ( 11.3 km ).
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W.E.Lay,University of Wichita,Kansas,publishes his results of wind tunnel studies for car models.Basically,he comes up with what Klemperer came up with in 1922.His fully-boat-tailed model achieved Cd 0.13,just like Jaray's.
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1933, Dymaxion Car(estimated at Cd 0.25 ) debuts at auto show.Bucky's spot is bumped by Walter Chrysler,Police Chief lets Fuller park the car at the curb entrance to the show.Everyone sees the car.They go nuts over it!!!!!!!!!!!
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1934, Douglas DC-3 ( Cd 0.12 ) debut,21-degree boat-tail and 192-mph ( 309 km/h ),astounds the aviation community.These planes are so good they are still in service today!!!!!!!
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1934,before introduction of their Cd 0.51 Airflow,Chrysler has 1933 DeSoto drive across the USA "backwards!!!!!!!" to try and educate American consumers that present auto styling is "backwards".Their plan doesn't work,the Airflow tanks in the marketplace,and when Carl Breer,aerodynamacist for Chrysler reveals aero-modded version of Airflow,with Cd 0.245,Walter Chrysler says" Forget it,streamlining is dead,no one will buy it."
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1934,Macchi-Castoldi MC.72 sea-plane,wins Schneider Trophy with record speed of 440-mph ( 709 km/h).Record stands to this day.
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1937,Hindenburg disaster,Lakehurst,New Jesey,ends the age of the great airships.
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1938," On the Triple Origin of Air Forces," published by Max Munk,Journal of Aeronautical Sciences.Munk gets into form,friction,and induced drag.The work and munk are considered top rate.I do not possess this work yet.It is cited in C.A.Marchaj's Aero and Hydrodynamics of Sailing.
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1939,World War-II breaks out in Europe.Japan is busy in China,has already aerial bombarded US ships in China,and Germany got to try out it's Luftwaffe in Spain during the "civil war",the world mobilizes for confrontation.
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1944,Miles Aircraft Company begins work on M52,supersonic plane.Fuselage is based on supersonic bullets.Soviet DshK 12.7mm machine-gun is firing Aberdeen boat-tailed ammo at 1,977-mph ( 3189 km/h ) MACH-2.58.
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1945,hostilities end with Fat Man and Little Boy.
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1945,Jack Northrop's all-wing,all-boat-tail,N9M-3 flying wing.
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1947,Capt.Chuck Yeager goes supersonic in Bell X-1,over Edward's AFB,California.The secret to supersonic flight was the all-moving tail which could operate in high turbulence and dancing center of pressure encountered in transonic flight.
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1949,"Fish propulsion in relation to design",published by R.W.Gawn,RINA ( sorry! I don't know what this acronym stands for yet ).
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1949,Hoerner publishes work on thick wing sections and cropped trailing edges.Yacht designers will attempt to "prune the wetted area" with "embryo transom hulls" ( truncated boat-tails ).Results aren't promising,as drag is reduced,but turbulence is so bad,rudders are rendered inoperable OOPS!
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1952,So-Cal belly-tank lakester,using discarded 319-gallon P-38 drop-tank for body,sets 198.34-mph ( 319.903 km/h ) land speed record at Bonneville.
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1953, US NAVY scientists,at David Taylor Model Basin,Carderock,Maryland,have decided that all submarines should have "fish-like" hulls like the 1900 USS Holland,and come out with X-Sub,USS Albacore which goes on to break successive submarine speed records ( sorry no numbers,guess it's still classified info ).
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1957,MG EX 181 pumpkin seed streamliner with Cd 0.12 sets land speed record of over 250-mph (403 km/h ) at Bonneville.
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1962,US NAVY begins Dolphin research,perplexed over the velocities achieved by the speedsters of the sea.
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1963,Walter H. Korff,Lockheed Aircraft Corp. lays out recipe for a Cd 0.21 automobile.
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1965,the Walter Korff designed Summers Brother's "Goldenrod" with 2,432 Bhp,and Cd 0.11-0.12 achieves 409.189-mph ( 659.982 km/h ) land speed record.
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1965,"Hydrodynamics of Dolphins," published by M. Kramer,Advances in Hydroscience 2,pp 111-130.
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1967,"World's Fastest Indian",Burt Munro's "Munro Special",1920 Indian motorcycle streamliner sets speed record ,which still stands.
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1969,R.G.S.White publishes recipe for a Cd 0.245 automobile.
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1969,W.A.Mair,GM Reasearch Labs,publishes his work on boat-tails.Starting with a cod's headed soupcan with Cd 0.165,Mair adds curved boattail until about 80=percent of section width is achieved,then walls of tail proceed at a constant 22-degree angle.If you stop the tail where he recommends,the Cd drops to 0.035.If you continue the tail to a point,you pick up another 14-percent drag reduction.
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1970,Soviet Alpha/Akula-class,nuclear submarine design debut.These are the fastest submarines,capable of almost 52-mph ( 83 km/h ) dived.They can out-run most torpedoes of the day,and embody heavily faired conning tower and organic fish-like hulls.
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1972,HONDA eco-mods their CIVIC with White's recipe,and with hybrid drive,achieve 173-mpg.
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October 23,1973,Arab Oil Embargo hits.Gasoline price doubles ( in California ) from $0.25/gallon,to $ 0.50/ gallon.
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March 1974,CAR and DRIVER Magazine publishes "CRISIS-FIGHTER-PINTO",eco-modding takes off in limited scale.
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1976,Urbasport Tri-Magnum (plans ) go on sale.
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1976,Dr.Alberto Morrelli's Pninfarina wind tunnel-developed CNR "banana car" unveiled.
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1976,Hucho publishes.
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1976,GM Chevrolet Corvette model candidate,scores Cd o.245 in GM's wind tunnel.
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1977,Space Shuttle Enterprise,with NASA boat-tail,after separation from 747 Mother-ship,glides TWICE as far as without boat-tail.
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1978,Mercedes-Benz sets Speed and mpg record with boat-tailed C-111.
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July,1980,an 18-inch ( 450-mm ) boat-tail,curving into a 20-degree angle,nets me 4-mpg with my 1970 VW Transporter.With the radial tires and other mods,I picked up a total 26.86 % improvement in highway mpg.
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1981,NASA releases photographs of their van boat-tail research at Edward's.It looks like Mair's.Mine looked like Mair's.
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1987,GM's Solaraycer pumpkin seed with Cd 0.12,wins World Solar Challenge,Australia.Dr. Paul MacCready comments that a car like that with internal combustion powertrain would be good for 400-mpg.
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1987, GM's Oldsmobile AEROTECH aero-modded March INDY-CAR chassis and estimated Cd 0.12 sets closed-course land speed record with 267-mph ( 430 km/h ).
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1990,Becker/Lyon #919 BMW motorcycle streamliner,Cd 0.11 sets speed record with 211-mph ( 340 km/h ) using 150-hp engine.
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1991,Phil Knox 1984 HONDA CIVIC CRX 1.3 picks up over 5-mph with track modified boat-tail to set club speed record.Cardboard and duct tape mods are good for about 60.5 mpg to the West Coast,and back to Texas.
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1992,GM Ultralite,1400-pounds,Cd 0.19,100-mpg at 50-mph.
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1994,GM Impact/ EV-1 sets land speed record at 178 mph ( 287 km/h ).They put a short boat-tail on the car and beat their record with 183 mph ( 295 km/h ),drag coefficient with the tail is estimated at Cd 0.172.
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Okay ! Enough is enough! I need to eat and go to work in a bit.There is a lot of material about limited production vehicles and kit vehicles that developed in the wake of the "Energy-Crisis" that some will know about others not.Since Cd 0.10 has actually been achieved on the road,it's a number to think about.
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I'm going to do some case-studies,where we can pick some things apart.I've waded out into deeper water than ever before and found some inconsistencies with respect to comments or claims made about streamlining and I think it would be good to clear the air on it.
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You all will need a break and rest after looking at all this material, and I am also a bit weary.If you can get a handle on this stuff you'll find yourself self-sufficient in crystal-balling your projects.Oil was at $143.00-barrel (US) today.It's a good time to know about aerodynamics.
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