Beware old and new aero data

[aerohead]

Originally Posted by JulianEdgar

The nearest parallel I can think to all of this is the old argument about engines 'needing back-pressure'.

I used to have this argument all the time, especially with older modifiers, about 20 years ago. They, too, would quote outdated magazine articles, outdated books, etc. Then they'd tell me the results of their tests - how power went down with free-flow exhausts. They had all sorts of theories as to why back-pressure was needed, and what terrible things would happen without enough back-pressure.

And, unfortunately, some people modifying their cars listened and were terrified of putting on large exhausts and freeflow mufflers.

I very much doubt 'engines needing back-pressure' was ever a valid concept, and with the advent of engine management and the ability to tune an engine so much more finely than with points and carbies, it is of course now just rubbish. But to this day, some people believe it.

That's why I hate seeing BS being spread in car modification - unless it is challenged, it gets a life of its own. And I really like seeing people succeed, not following bad advice and so going on to achieve substandard outcomes.

Back issues of HOT ROD Magazine are your friend.They have published for decades on this topic and have the controlled,laboratory,engine test-cell, dynamometer data to back up all the dialogue.

[freebeard]

This may be the only photograph of this car.

This the one?


https://www.allcarindex.com/producti.../fkfs-k-wagen/


https://www.fkfs.de/aktuelles/pressebilder

'He positioned the radiator air intake at the very nose,in the area of highest pressure,then ducted the cooling air out again at the base of the windshield.Just at the point where the airflow was starting to slow down and enter a low-pressure area,Kamm's design ejected a shot of relatively high pressure air.

It must have had an OP fan.

[aerohead]

Originally Posted by freebeard

This the one?


https://www.allcarindex.com/producti.../fkfs-k-wagen/


https://www.fkfs.de/aktuelles/pressebilder

It must have had an OP fan.

That's K2. And you can see Kamm's extractor vent at the base of the windscreen.K2 and K5 are the only K-cars with Kamm's cooling system.For K5,you'd take K2 and put Volkswagen's 'ideal',low nose from 1976 onto it.In the orthogonal view photograph of K5 undergoing tuft testing in HOT ROD,shot from behind and above the car,you can't even see the nose,it's so low.

[freebeard]

A Rabbit nose on that would look weird. Volkhart-Sagitta?

...then ducted the cooling air out again at the base of the windshield...

I confuse easily. More like Morelli?

Trying [in vain] to find the Hot Rod picture I went down a rabbit hole about the XP-39

May 1, 2018_#59_pbehn_Oct 30, 2013

When discussing the Meredith effect, as with everything there is no free lunch, on full power the water pumps on a Merlin consumed 40BHP.

[aerohead]

Originally Posted by freebeard

A Rabbit nose on that would look weird. Volkhart-Sagitta?

I confuse easily. More like Morelli?

Trying [in vain] to find the Hot Rod picture I went down a rabbit hole about the XP-39

It would be the very organic,fully radius'd,low stagnation point nose Hucho depicted in his text.If I hadn't lost everything to photobucket I could have shared the image.

[JulianEdgar]

Originally Posted by aerohead

*Perhaps Australia offers remedial classes in reading for comprehension and critical thinking.Some of you're comments suggest a complete lack of perspicacity,and a complete failure of Richard Feyman's admonition,to never open your mouth unless you've exhausted all avenues of exploration as to the possibility that you're incorrect in your premises.I do give you high marks in 'insult.'

Unlike what you write, the material in my book (which basically I am quoting from for nearly everything I write here) was checked before publication by four expert car aerodynamacists.

They included:

• the head of aerodynamics at a major car company
• an F1 aerodynamicist
• a professor of aerospace (and author of two major books on car aero)

...and of course my official technical consultant and reviewer for every page in the book, Dick Barnard. Dick's CV:

Richard Barnard is a world-renowned aerodynamicist. He started his career as an undergraduate aeronautical engineering apprentice at Handley Page Ltd, and later became Principal Lecturer and Postgraduate Research Tutor at the University of Hertfordshire, and is currently a Visiting Research Fellow. He is also a founder member of the UK Wind Engineering Society, and a Fellow of the Royal Aeronautical Society (FRAeS). He has been a consultant for numerous companies, including Jaguar and Rolls-Royce Bentley. Richard is the author of Road Vehicle Aerodynamics and has written many technical papers.

That is why I am very confident in the material.

So when I read what you write, which is very often completely or in part wrong, I am cross that you are leading people astray. It becomes even worse when you persist in saying the same thing, despite the errors in what you are saying being pointed out.

Misconceptions are fine - no one is perfect - but to continue to give people poor advice, is in my opinion, unforgivable.

I have this really odd moral belief that people modifying their cars should actually be given the best advice available. That way, they spend less of their money, time, effort and enthusiasm being wasted by pursuing courses of action that result in outcomes that often don't achieve what was promised.

[MeteorGray]

This debate reminds me of the medical advice we're being given by various experts in the field about the coronavirus.

EG, should we wear a mask or should we not?

What seems simple turns out to be not so much. :-)

[freebeard]

Reminds me of:

https://imgs.xkcd.com/comics/duty_calls.png

[Fat Charlie]

Love that one.

[freebeard]

How about this? The door has been opened, in lawyer-speak, to comparing airplanes and 1930s aerodynamics to today. 'How about a little of this?'[Dennis Hopper]


kfgo.com: Delivery drone flies medical supplies to Britain’s Isle of Wight


https://en.m.wikipedia.org/wiki/Burnelli_UB-14