11-18-2013, 03:01 PM
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#1 (permalink)
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Master EcoModder
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Latest Hucho book questions
Does the latest Hucho book have any updated or better information on optimum car nose shapes? Tail shapes?
For example, his Fourth Edition, page 158, has drawings and graphs on optimized nose shapes, relative height of stagnation point, etc.
I'm curious if the newer edition addresses that, and especially if the planform (as seen from above) shape is considered. Round, elliptical, etc. shape is optimum?
The latest Porsche cars such as Carrera GT have elliptical planform, and I wonder if Hucho or any other good source adresses this.
Thoughts, cites, and especially pictures or exhibits posted here from such sources would be much appreciated!
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11-18-2013, 05:33 PM
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#2 (permalink)
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Master EcoModder
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Quote:
Originally Posted by Otto
I'm curious if the newer edition addresses that, and especially if the planform (as seen from above) shape is considered. Round, elliptical, etc. shape is optimum?
The latest Porsche cars such as Carrera GT have elliptical planform, and I wonder if Hucho or any other good source adresses this.
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Porsche Carrera GT
I would be curios to see where exactly the air is detaching from the rear quarters of the Carrera GT.
http://s184.photobucket.com/user/kac...?sort=3&page=1
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Last edited by kach22i; 11-18-2013 at 05:38 PM..
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11-23-2013, 05:53 PM
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#3 (permalink)
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Master EcoModder
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Hucho
Quote:
Originally Posted by Otto
Does the latest Hucho book have any updated or better information on optimum car nose shapes? Tail shapes?
For example, his Fourth Edition, page 158, has drawings and graphs on optimized nose shapes, relative height of stagnation point, etc.
I'm curious if the newer edition addresses that, and especially if the planform (as seen from above) shape is considered. Round, elliptical, etc. shape is optimum?
The latest Porsche cars such as Carrera GT have elliptical planform, and I wonder if Hucho or any other good source adresses this.
Thoughts, cites, and especially pictures or exhibits posted here from such sources would be much appreciated!
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In his 4th-Edition,does Hucho show the VW body research from 1981?
In his 2nd -Ed he shared a nested schematic of a hand full of body forms tested,including the AVA Schl'o'r wagen.
He has side elevation and plan-views for all shown.Cds range to 0.15.
In his 1978 SAE Paper he eludes to a Cd 0.14 'full-tail' variant of the VW 'Flow' body.
It's worth looking for.
I'm collecting material for threads including plan-views but am nowhere near ready for posting.
Some cars that plan-views are available:
1922 Jaray pumpkin seed
1922 Wolfgang Klemperer 'minivan'
1933 Walter E.Lay pumpkin seed
circa-1935 Koenig-Fachsenfeld streamline body of revolution car
circa-1935 K-Car development (FKFS)
1939 Schl'o'rwagen
1955 VW Beetle
1955 VW Karman Ghia
1957 MG EX 181 LSR streamliner
1961 Jaguar E-Type
1968 MIRA/R.G.S.White Cd 0.245 recipe car
1974 VW Golf/Rabbit
1978 D-B M-B C-111 III record car
1980 VW 2000
1981 VW Blunt
1981 VW Drop
1981 VW Flow (truncated)
1981 VW Flow (full-tail)
1987 GM/AeroVironment Impact
1987 GM Olsmobile AEROTECH (long tail)
1988 Lamborghini Countach
1996 HONDA Dream III solar racer
1963 Walter Korff streamliner
2013 Porsche 918 Spyder
Many factory shop manuals will have accurate line drawings including plna views.
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11-27-2013, 04:11 AM
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#4 (permalink)
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11-27-2013, 06:46 PM
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#5 (permalink)
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Master EcoModder
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Hucho
Hucho mentions half-bodies and wing sections as the 'ideal' forms for low drag.
*Wings require dimensions which would be hard to pull off in a passenger car.Toyota's Ra-Ra is the only commercial example I've seen.
*The half-bodies,Jaray's,Reid's,Heald's,Schl'o'rwagen's,Sola rWorld GT,Cambridge University's CUER,etc. have the 'BUG' nose which is ideal for sub-transonic flow.In plan view it's essentially a semi-circle.Hucho eludes to them in his section on commercial vehicles when he discusses the 'bulbous' nose and it's superior crosswind performance.It's what I chose for the 'Template.'
PS Short of wing sections,only the half-body has the proper boat-tailing which allows full pressure recovery and entire elimination of the wake,the key to really low-drag streamlining.
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Last edited by aerohead; 11-27-2013 at 06:58 PM..
Reason: add PS
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12-04-2013, 07:52 PM
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#6 (permalink)
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Master EcoModder
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planform
Quote:
Originally Posted by Otto
Does the latest Hucho book have any updated or better information on optimum car nose shapes? Tail shapes?
For example, his Fourth Edition, page 158, has drawings and graphs on optimized nose shapes, relative height of stagnation point, etc.
I'm curious if the newer edition addresses that, and especially if the planform (as seen from above) shape is considered. Round, elliptical, etc. shape is optimum?
The latest Porsche cars such as Carrera GT have elliptical planform, and I wonder if Hucho or any other good source adresses this.
Thoughts, cites, and especially pictures or exhibits posted here from such sources would be much appreciated!
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I spent some time in my rat's nest looking at the plan views of low drag vehicles.
It looks like the tail section of the 3.92:1,(25.5% thickness) symmetrical wing section has demonstrated the lowest drag over the decades.
As measured from the widest part of the vehicle,it would extend back 2.39X times body width.
I believe it's posted at the Aerodynamic Streamlining Template thread as "Drag per unit length vs thickness chord ratio,2-D flow,wing/strut sections."
It's the middle section of the three in the table.
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