Hucho's 'templates' - Fuel Economy, Hypermiling, EcoModding News and Forum

aerohead · 01-06-2021, 04:26 PM

In Hucho's, 'Aerodynamics of Road Vehicles', 2nd-Edition, December 1986, on over the 540-pages of actual text, I identified 812 visual-quanta 'templates', on 259 different pages.
All of my library is full of these types of visual teaching tools.

JulianEdgar · 01-06-2021, 06:08 PM

Quote:

Originally Posted by aerohead

In Hucho's, 'Aerodynamics of Road Vehicles', 2nd-Edition, December 1986, on over the 540-pages of actual text, I identified 812 visual-quanta 'templates', on 259 different pages.
All of my library is full of these types of visual teaching tools.

People often see what they want to see.

And what I want to see is a section in any aerodynamics textbook that applies a template as has been so often been encouraged here. Viz:

- Show where there is separated and attached flow on existing cars
- Guide the shape of rear extensions
- Show how rear spoilers on sedans should be positioned and shaped
- Allow the assessment of the ‘aerodynamic purity’ of cars

I don't know of even one textbook or technical paper that does so.

That's the reality: encouraging people to apply a predetermined shape as some sort of tool to help them in their aerodynamic car modifications is to simply mislead.

ME_Andy · 01-07-2021, 12:30 AM

Have you read Hucho's book, Julian? I haven't either, but that seems like the obvious place to start.

JulianEdgar · 01-07-2021, 01:20 AM

Quote:

Originally Posted by ME_Andy

Have you read Hucho's book, Julian? I haven't either, but that seems like the obvious place to start.

Yes, I first read that edition of Hucho in about 1988, and I've had my own copy for about a decade. I also have the current (5th) edition.

The only thing remotely like Aerohead's conception of a template in Hucho is this diagram, that shows five completely different shapes, all with low drag.

All the rest (applying the template to existing cars to guide modifications, etc) is just Aerohead's theory. Those applications are supported in no textbook or paper I have ever read.

Here is the reference list of the papers and books I used when writing my book. (I read many more than are on this list; these are the ones I quote from.)

Books

Allen, J, Aerodynamics – the science of air in motion, 2nd edition, Granda Publishing, 1982

Barnard, RJ, Road Vehicle Aerodynamic Design, 3rd edition, MechAero, 2009

Frere, P, Porsche 911 Story, Haynes Publishing, 7th Edition, 2002

Hucho, WH (Ed), Aerodynamics of Road Vehicles, Butterworths, 1987

Katz, J, Race Car Aerodynamics – Designing for Speed, Robert Bentley Publishers, 1995

Kieselbach, RJF, Stromlinienautos in Deutschland, Kohlhammer, 1982

Scibor-Rylski, AJ, Road Vehicle Aerodynamics, Pentech Press, 1975

Tamai, G, The Leading Edge – Aerodynamic Design of Ultra-streamlined Land Vehicles, Bentley Publishers, 1999

Papers

Atkinson, J., “Research into the Potential of Variable Aerodynamic Properties to Modify Ground Vehicle Behaviour”, Coventry University, 2014

Bannister, M., "Drag and Dirt Deposition Mechanisms of External Rear View Mirrors and Techniques Used for Optimisation," SAE Technical Paper 2000-01-0486, 2000

Barnard, R.H., Bullen, P.R., Qiao, J., “Fixed and Variable Cooling Outlet Geometries for the Minimisation of Associated Drag,” Procs. 5th MIRA International Vehicle Aerodynamics Conference, Warwick, U K, 13-15 October 2004

Barth, R., "Effect of Unsymmetrical Wind Incidence on Aerodynamic Forces Acting on Vehicle Models and Similar Bodies," SAE Technical Paper 650136, 1965

Beauvais, F., Tignor, S., and Turner, T., "Problems of Ground Simulation in Automotive Aerodynamics," SAE Technical Paper 680121, 1968

Buckley, F., "ABCD - An Improved Coast Down Test and Analysis Method," SAE Technical Paper 950626, 1995

Buljac, A., Džijan, I., Korade, I. et al. “Automobile aerodynamics influenced by airfoil-shaped rear wing”, International Journal of Automotive Technology, 2016

Buscariolo, F., Magazoni, F., Maruyama, F., Alves, J. et al., "Aerodynamic Enablers Review for Automotive Applications," SAE Technical Paper 2016-36-0203, 2016.

Cai, J., Kapoor, S., Sikder, T., and He, Y., "Effects of Active Aerodynamic Wings on Handling Performance of High-Speed Vehicles," SAE Technical Paper 2017-01-1592, 2017

Chaligné S., Turner R., Gaylard A. (2018) The Aerodynamics Development of the New Land Rover Discovery. In: Wiedemann J. (eds) Progress in Vehicle Aerodynamics and Thermal Management. FKFS 2017. Springer, Cham

Cooper, K., Syms, J., and Sovran, G., "Selecting Automotive Diffusers to Maximise Underbody Downforce," SAE Technical Paper 2000-01-0354, 2000

D'Hooge, A., Palin, R., Johnson, S., Duncan, B. et al., "The Aerodynamic Development of the Tesla Model S - Part 2: Wheel Design Optimization," SAE Technical Paper 2012-01-0178, 2012

Emmelmann, H., Berneburg, H., and Schulze, J., "The Aerodynamic Development of the Opel Calibra," SAE Technical Paper 900317, 1990

Evrard, A. et al, “Comparative effects of vortex generators on Ahmed’s squareback and minivan car models”, Journal of Automobile Engineering, I Mech E, 2017

Froling, T. and Juechter, T., "2006 Chevrolet Corvette C6 Z06 Aerodynamic Development," SAE Technical Paper 2005-01-1943, 2005

Garcia de la Cruz, J., Brackston, R., and Morrison, J., "Adaptive Base-Flaps Under Variable Cross-Wind," SAE Technical Paper 2017-01-7000, 2017

George, A., "Automobile Aerodynamic Noise," SAE Technical Paper 900315, 1990

Howell, J. and Le Good, G., "The Influence of Aerodynamic Lift on High Speed Stability," SAE Technical Paper 1999-01-0651, 1999

Janson, T, and Piechna, J., “Numerical Analysis of Aerodynamic Characteristics of a High-Speed car with Moveable Bodywork Elements”, Archive of Mechanical Engineering, Volume 62, Issue 4, Pages 451–476, ISSN (Online) 2300-1895, 2015

Kataoka, T., China, H., Nakagawa, K., Yanagimoto, K. et al., "Numerical Simulation of Road Vehicle Aerodynamics and Effect of Aerodynamic Devices," SAE Technical Paper 910597, 1991

Kataoka, S., et al, “Aerodynamics for Lancer Evolution X”, Mitsubishi Motors Technical Review, No 20, 2008

Kawakami, M., Murata, O., and Maeda, K., "Improvement in Vehicle Motion Performance by Suppression of Aerodynamic Load Fluctuations," SAE Int. J. Passeng. Cars - Mech. Syst. 8(1):205-216, SAE Technical Paper 2015-01-1537, 2015

Kawamata, H., Kuroda, S., Tanaka, S., and Oshima, M., "Improvement of Practical Electric Consumption by Drag Reducing under Cross Wind," SAE Technical Paper 2016-01-1626, 2016

Koike, M., Nagayoshi, T., and Hamamoto, N., “Research on Aerodynamic Drag Reduction by Vortex Generators,” Mitsubishi Motors Technical Review, 2004, No 16.

Landström, C., Walker, T., Christoffersen, L., and Löfdahl, L., "Influences of Different Front and Rear Wheel Designs on Aerodynamic Drag of a Sedan Type Passenger Car," SAE Technical Paper 2011-01-0165, 2011

Larose, G., Belluz, L., Whittal, I., Belzile, M. et al., "Evaluation of the Aerodynamics of Drag Reduction Technologies for Light-duty Vehicles: a Comprehensive Wind Tunnel Study," SAE Int. J. Passeng. Cars - Mech. Syst. 9(2):772-784, 2016

Le Good, G., Howell, J., Passmore, M., and Garry, K., "On-Road Aerodynamic Drag Measurements Compared with Wind Tunnel Data," SAE Technical Paper 950627, 1995

Le Good, G., Howell, J., Passmore, M., and Cogotti, A., "A Comparison of On-Road Aerodynamic Drag Measurements with Wind Tunnel Data from Pininfarina and MIRA," SAE Technical Paper 980394, 1998

Levin, J., and Rigdal R., “Aerodynamic analysis of drag reduction devices on the underbody of a SAAB 9-3 by using CFD”, Chalmers University of Technology, Gothenburg, Sweden, 2011

Littlewood, R., Passmore, M., and Wood, D., "An Investigation into the Wake Structure of Square Back Vehicles and the Effect of Structure Modification on Resultant Vehicle Forces," SAE Int. J. Engines 4(2):2629-2637, SAE Technical Paper 2011-37-0015, 2011

Leuschen J., Cooper K.R. (2009) Summary of Full-Scale Wind Tunnel Tests of Aerodynamic Drag-Reducing Devices for Tractor-Trailers. In: Browand F., McCallen R., Ross J. (eds) The Aerodynamics of Heavy Vehicles II: Trucks, Buses, and Trains. Lecture Notes in Applied and Computational Mechanics, vol 41. Springer, Berlin, Heidelberg

Lew, C., Gopalaswamy, N., Shock, R., Duncan, B. et al., "Aerodynamic Simulation of a Standalone Rotating Treaded Tire," SAE Technical Paper 2017-01-1551, 2017

Lounsberry, T., Gleason, M., and Puskarz, M., "Laminar Flow Whistle on a Vehicle Side Mirror," SAE Technical Paper 2007-01-1549, 2007

Marcell, R. and Romberg, G., "The Aerodynamic Development of the Charger Daytona for Stock Car Competition," SAE Technical Paper 700036, 1970

Mayer, W. and Wiedemann, J., "The Influence of Rotating Wheels on Total Road Load," SAE Technical Paper 2007-01-1047, 2007

Mayer, W. and Wickern, G., "The New Audi A6/A7 Family - Aerodynamic Development of Different Body Types on One Platform," SAE Int. J. Passeng. Cars – Mech. Syst. 4(1):197-206, SAE Technical paper 2011-01-0175, 2011

Meder, J., “Aerodynamic Shapeshifter – The New Porsche 911 Turbo”, FKFS - 9th Aerodynamic Conference, 2013

Nakamura, D., Onishi, Y., and Takehara, Y., "Flow Field Analysis in the Development of the 2013 Model Year Accord Hybrid," SAE Technical Paper 2015-01-1534, 2015, https://doi.org/10.4271/2015-01-1534.

Ng, E., Watkins, S., Johnson, P., and Mole, L., "Use of a Pressure-Based Technique for Evaluating the Aerodynamics of Vehicle Cooling Systems," SAE Technical Paper 2002-01-0712, 2002

Okada, Y., Nouzawa, T., Nakamura, T., and Okamoto, S., "Flow Structures above the Trunk Deck of Sedan-Type Vehicles and Their Influence on High-Speed Vehicle Stability 1st Report: On-Road and Wind-Tunnel Studies on Unsteady Flow Characteristics that Stabilize Vehicle Behavior," SAE Int. J. Passeng. Cars – Mech. Syst. 2(1):138-156, SAE Technical Paper 2009-01-0004, 2009

Palaskar, P., "Effect of Side Taper on Aerodynamics Drag of a Simple Body Shape with Diffuser and without Diffuser," SAE Technical Paper 2016-01-1621, 2016

Park, H., "A Rear-View Side Mirror with Exterior Lens to Improve Field of View and Aerodynamics of Automobiles," SAE Technical Paper 2017-01-1358, 2017, https://doi.org/10.4271/2017-01-1358.

Passmore, M. and Le Good, G., "A Detailed Drag Study Using the Coastdown Method," SAE Technical Paper 940420, 1994

Pitman, J. and Gaylard, A., “An experimental investigation into the flow mechanisms around an SUV in open and closed cooling air conditions”, 11th FKFS Conference: Progress in Vehicle Aerodynamics and Thermal Management, 2017

Sapnaras, D. and Dimitriou, I., "Experimental Analysis of the Underbody Pressure Distribution of a Series Vehicle on the Road and in the Wind Tunnel," SAE Technical Paper 2008-01-0802, 2008

Santer, R. and Gleason, M., "The Aerodynamic Development of the Probe IV Advanced Concept Vehicle," SAE Technical Paper 831000, 1983

Schenkel, F., "The Origins of Drag and Lift Reductions on Automobiles with Front and Rear Spoilers," SAE Technical Paper 770389, 1977

Sebben, S., "Numerical Simulations of a Car Underbody: Effect of Front-Wheel Deflectors," SAE Technical Paper 2004-01-1307, 2004

Shigarkanthi, V., Damodaran, V., Soundararaju, D., and Kanniah, K., "Application of Design of Experiments and Physics Based Approach in the Development of Aero Shutter Control Algorithm," SAE Technical Paper 2011-01-0155, 2011

Simmonds, N., Pitman, J., Tsoutsanis, P., Jenkins, K. et al., "Complete Body Aerodynamic Study of three Vehicles," SAE Technical Paper 2017-01-1529, 2017, https://doi.org/10.4271/2017-01-1529.

Tortosa, N. and Karbon, K., "Aerodynamic Development of the 2011 Chevrolet Volt," SAE Int. J. Passeng. Cars – Mech. Syst. 4(1):166-171, 2011

Unni, T., "Numerical Investigation on Aerodynamic Effects of Vanes and Flaps on Automotive Underbody Diffusers," SAE Technical Paper 2017-01-2163, 2017.

Vdovin, A., “Investigation of Aerodynamic Resistance of Rotating Wheels on Passenger Cars” Chalmers University of Technology, Gothenburg, Sweden, 2013

Wang, F., Yin, Z., Yan, S., Zhan, J. et al., "Validation of Aerodynamic Simulation and Wind Tunnel Test of the New Buick Excelle GT," SAE Int. J. Passeng. Cars - Mech. Syst. 10(1):195-202, 2017, SAE Technical Paper 2017-01-1512

Wickern, G. and Brennberger, M., "Scaling Laws in Automotive Aeroacoustics," SAE Technical Paper 2009-01-0180, 2009

Magazine

Sherman, D., “Drag Queens: Aerodynamics Compared”, Car and Driver, June 2014

aerohead · 01-08-2021, 11:16 AM

Quote:

Originally Posted by JulianEdgar

People often see what they want to see.

And what I want to see is a section in any aerodynamics textbook that applies a template as has been so often been encouraged here. Viz:

- Show where there is separated and attached flow on existing cars
- Guide the shape of rear extensions
- Show how rear spoilers on sedans should be positioned and shaped
- Allow the assessment of the ‘aerodynamic purity’ of cars

I don't know of even one textbook or technical paper that does so.

That's the reality: encouraging people to apply a predetermined shape as some sort of tool to help them in their aerodynamic car modifications is to simply mislead.

1) One textbook would be, 'Aerodynamics of Road Vehicles', 2nd-Edition, page 185, Figure 4.104.
In 1973, Janssen and Hucho, working on detail optimization of the upcoming 4-door, VW Golf, deviated greatly in terms of style from Giugiaro's original design, obtaining a 33% drag reduction, to demonstrate what could be reached over and above, by departing from the stylistic concept.
Exactly what we here at EcoModder.com endeavor for.
The Golf's drag minimum was achieved when the roofline matched the 'template' profile.( Figure 4.47, page-145 )
------------------------------------------------------------------------------------

2)* The 2016, Cd 0.19, Mercedes-Benz IAA extensible boat-tail section is a perfect 'template' match, according the Daimler-Benz' wind tunnel photographs and video.
* The Audi E-tron experiences a 20-count drag reduction when the 'raked' roofline is exchanged for the more template-like 'Sportback' roofline.
* The Audi SQ2, for 2019, enjoyed an 'aero improvement' by an elongation of its roof spoiler ( something the Cd 0.27, Mitsubishi Mirage takes to the limit).
* Volkswagen's 1981 Flow-Body ( long-tail ) experiences a 10-count drag reduction when the 'template' is followed to its conclusion ( Cd 0.140 ), Figure 4.120, page- 200, top of upper table.
* The Daimler-Benz, Mercedes-Benz, C-111 III demonstrates a drag reduction, from Cd 0.237, to Cd 0.178, when it's boat-tail 'template' is carried to its conclusion. Figure 4.42, page- 142
* Sunbeam utilized the 'template' for the aft-body of it's SUNBEAM 1000-HP land speed record car of the 1920s.
--------------------------------------------------------------------------------------
3) For notchback spoilers. please see:
1965 Ford Mustang fastback (sic)
1982 Pontiac Trans AM Firebird
1990 Opel Calibra
1993 Volvo ECC
1993 Chevrolet Camaro V-6
1997 Nissan 200SX
1998 Toyota MR2
2014 Audi RS5
2014 Chevrolet Camaro SS 1LE
2015 Alfa Romeo 4C
2015 Lexus RCF
2018 KIA Stinger
2012 Toyota GR SUPRA
------------------------------------------------------------------------------------
As to assessing the aerodynamic 'purity' of a car, that's kind of subjective, and non-quantifiable.
I'd go no further than 'streamlined.'
Hucho used the terms ' optimum' and 'ideal' interchangeably in his 2nd-Edition.
Hucho explicitly described the streamline half-body as 'optimum'. The reader is free to interpret that adjective as they please.
Other than 'wings', the streamlined body of revolution-based half-body, is the only other path to ultra-low-drag according to Hucho.
The discussion of 'wings' is for it's own dedicated thread.
Without any 'testing' or 'measurements,' I've found the 'template' to be adequate for facilitating land speed records, distance records, and low-emissions records.
For amateur modifications it's shown a propensity for low drag, as a 'first' and perhaps 'last' approximation for streamlining.

freebeard · 01-08-2021, 11:52 AM

Quote:

In 1973, Janssen and Hucho, working on detail optimization of the upcoming 4-door, VW Golf, deviated greatly in terms of style from Giugiaro's original design, obtaining a 33% drag reduction, to demonstrate what could be reached over and above, by departing from the stylistic concept.

Pics or it didn't happen.

JulianEdgar · 01-08-2021, 03:30 PM

Quote:

Originally Posted by freebeard

Pics or it didn't happen.

Here's the pic. It has nothing to do with any template.

JulianEdgar · 01-08-2021, 03:44 PM

Quote:

Originally Posted by aerohead

1) One textbook would be, 'Aerodynamics of Road Vehicles', 2nd-Edition, page 185, Figure 4.104.
In 1973, Janssen and Hucho, working on detail optimization of the upcoming 4-door, VW Golf, deviated greatly in terms of style from Giugiaro's original design, obtaining a 33% drag reduction, to demonstrate what could be reached over and above, by departing from the stylistic concept.
Exactly what we here at EcoModder.com endeavor for.
The Golf's drag minimum was achieved when the roofline matched the 'template' profile.( Figure 4.47, page-145 )
------------------------------------------------------------------------------------

Nether of your cited diagrams have anything to do with template. Neither mentions a template, shows a template or makes any claim that a predetermined shape is applicable in any way.

So I'll say again:

What I want to see is a section in any aerodynamics textbook that applies a template as has been so often been encouraged here. Viz:

- Show where there is separated and attached flow on existing cars
- Guide the shape of rear extensions
- Show how rear spoilers on sedans should be positioned and shaped
- Allow the assessment of the ‘aerodynamic purity’ of cars

As we both know, no such textbook or paper exists - and for good reason.

Quote:

2)* The 2016, Cd 0.19, Mercedes-Benz IAA extensible boat-tail section is a perfect 'template' match, according the Daimler-Benz' wind tunnel photographs and video.
* The Audi E-tron experiences a 20-count drag reduction when the 'raked' roofline is exchanged for the more template-like 'Sportback' roofline.
* The Audi SQ2, for 2019, enjoyed an 'aero improvement' by an elongation of its roof spoiler ( something the Cd 0.27, Mitsubishi Mirage takes to the limit).
* Volkswagen's 1981 Flow-Body ( long-tail ) experiences a 10-count drag reduction when the 'template' is followed to its conclusion ( Cd 0.140 ), Figure 4.120, page- 200, top of upper table.
* The Daimler-Benz, Mercedes-Benz, C-111 III demonstrates a drag reduction, from Cd 0.237, to Cd 0.178, when it's boat-tail 'template' is carried to its conclusion. Figure 4.42, page- 142
* Sunbeam utilized the 'template' for the aft-body of it's SUNBEAM 1000-HP land speed record car of the 1920s.

This is exactly the same logic as saying '225 section tyres are best' and then citing every car that uses that tyre as if it is sound evidence for the proposition that 225 section tyres are best.

Quote:

--------------------------------------------------------------------------------------
3) For notchback spoilers. please see:
1965 Ford Mustang fastback (sic)
1982 Pontiac Trans AM Firebird
1990 Opel Calibra
1993 Volvo ECC
1993 Chevrolet Camaro V-6
1997 Nissan 200SX
1998 Toyota MR2
2014 Audi RS5
2014 Chevrolet Camaro SS 1LE
2015 Alfa Romeo 4C
2015 Lexus RCF
2018 KIA Stinger
2012 Toyota GR SUPRA
------------------------------------------------------------------------------------

What about them? None were developed using a template, or even a predetermined shape of any type. As for this list being evidence of anything, see my comment above about tyres.

Quote:

As to assessing the aerodynamic 'purity' of a car, that's kind of subjective, and non-quantifiable.
I'd go no further than 'streamlined.'
Hucho used the terms ' optimum' and 'ideal' interchangeably in his 2nd-Edition.
Hucho explicitly described the streamline half-body as 'optimum'. The reader is free to interpret that adjective as they please.
Other than 'wings', the streamlined body of revolution-based half-body, is the only other path to ultra-low-drag according to Hucho.
The discussion of 'wings' is for it's own dedicated thread.

Hmm, so overlaying a template over cars and saying 'it would be so much better if only it matched the template' is as nonsensical as it sounds?

Quote:

Without any 'testing' or 'measurements,' I've found the 'template' to be adequate for facilitating land speed records, distance records, and low-emissions records.

For amateur modifications it's shown a propensity for low drag, as a 'first' and perhaps 'last' approximation for streamlining.

Yes, and just as with the tyres, I've found that 225-section tyres give excellent results on many cars - something which proves absolutely nothing about 225 tyres.

Unfortunately the application of the template is just your weird theory - and I say 'unfortunately' because if it were as easy as that, gee, that would be good.

To others reading this, I'll say again. Don't believe me - just look in any car aero textbook and find those major sections extolling the value of a template. There aren't any.