Why don't vehicles have aerofoils to partially take the weight of the car?

[freebeard]

Originally Posted by kach22i

FREEBEARD, the doughnut shaped things you mention are 2 foot and not 4 foot and called tires?

You lost me buddy, please clarify for those that just woke up and the coffee hasn't kicked in yet.

Why was I posting at 7:51 AM? That (questionable) idea was generally a stern wheeler hovercraft, the 'donut' would be a circular skirt. With a relatively high weight load it would fly low and need the impact resistance of a modern tire, at least on the leading edge.

Maybe I was just baiting Julian Edgar.

I don’t see the point - and I see a lot of negatives - in sharing ideas for which there is little / no evidence, and of which no testing has been done. Basically every conspiracy theory, for example, matches that description.

Conspiracy theories require conspiracy analysts. Not everyone [have/has?] this guy's resources:

Dynamic King Suspension on My Wingless Airplane | Scrappy #52

[JulianEdgar]

Originally Posted by kach22i

I'm not familiar with actual data on this, but phrases/experiences like the "steering got light" when going fast, and seat of the pants experiences going fast on a secondary highway with rolling hills feeling the car lift like a roller coaster ride is conformation enough for me.

The physics is there, the automobile will react to those forces be they F = ma in the vertical or aerodynamic.

If you reduce the effective weight of the car by half through aerodynamic lift, you will decrease the unloaded car's suspension static deflection by half. If the car has a static deflection of (say) 3 inches, and you have 50 per cent lift, the car will ride 1.5 inches higher. That will increase CdA, and may well in fact cause further lift.

(The opposite happens when you lower a car* - Cd, CdA and Cl all tend to decrease. *Road cars, with normal ground clearance.)

[JulianEdgar]

Originally Posted by kach22i

I am always amazed by humans, one person knows one thing, another knows another and somehow progress is achieved. Like ants building a massive ant hill.

It's a nice idea but I basically never see it occurring on web discussion groups relating to car modification. What I do see is that many people like to see themselves as part of that process, I think because it makes them feel good about themselves. ("I am not just contributing mindless garbage but I am actually helping Fred!")

The best example I ever saw was on the Honda Insight discussion group. One guy there developed, from scratch, really excellent electronic products for the car. He was light-years ahead of everyone else (including me of course), doing 99 per cent of the idea creation, and then 99 per cent of the test and development of those ideas. Fine!

But what gobsmacked me is that so many others on that group somehow thought they'd made major contributions to the development of those products! I even wrote to the bloke once and asked if he didn't get cross when other people were taking implicit credit for what he was producing, when they'd done basically nothing! He replied that it didn't worry him - but then again, he was selling the products to that group and so wanted a smooth ride.

In this group, when people link to references and do valid on-road tests, it's a completely different ballgame to those who just speculate.

[freebeard]

I always try to document my references. Here's an example:


justacarguy.blogspot.com: the floofy gold ones are the best

[j-c-c]

Originally Posted by JulianEdgar

Ah well, be stunned!

I don’t see the point - and I see a lot of negatives - in sharing ideas for which there is little / no evidence, and of which no testing has been done. Basically every conspiracy theory, for example, matches that description.

I am no longer "stunned", I am now sadded, but hopeful of my idea, you are the only one that "doesn't see the point".

And your conspiracy theory analogy has been wrong numerous times in the world, with plenty of examples.

Please don't let this discussion devolve into a tin hat conversation, as that ain't my thing, but I will not categorically refuse to listen to another's theory or idea because it has yet to be "tested".

Doesn't sound like you have enjoyed many brainstorming sessions that you have had to consider other inputs on a level playing field, other than your own?

[JulianEdgar]

Originally Posted by j-c-c

I am no longer "stunned", I am now sadded, but hopeful of my idea, you are the only one that "doesn't see the point".

And your conspiracy theory analogy has been wrong numerous times in the world, with plenty of examples.

Please don't let this discussion devolve into a tin hat conversation, as that ain't my thing, but I will not categorically refuse to listen to another's theory or idea because it has yet to be "tested".

Doesn't sound like you have enjoyed many brainstorming sessions that you have had to consider other inputs on a level playing field, other than your own?

Anyone can come up with ideas - and people very often do. I've had three this morning.

- I wonder if I put cabin outlet vents on the roof whether that would energise the boundary layer and reduce flow separation?

- I wonder if the sky is blue above my house today because someone is holding up a big blue sheet?

- I wonder if I pressurised the frame of my bicycle at say 100 psi whether I could run tubes with paper thin wall thickness?

My classic story of an idea is the probably apocryphal one of WWII. Someone wrote to the UK government saying they had an idea for finding all the German Wolfpack submarines in the Atlantic.

Yes, asked the government, what is your idea?

Oh, said the correspondent, we should just boil the ocean dry.

Ideas are ten a penny - like opinions. Everyone has them. Ideas alone are worthless.

I am also amazed how people have, and I can only describe it as the arrogance, to believe ideas they come up with are worthy of consideration... without their having done even an hour of research or any testing at all. For example, I would never, ever suggest how solar race teams could do better. They are so far ahead of anything I could come up with that it's just not funny. We've had a person in this group suggest that the head of Porsche aerodynamics knows little. He knows so much more than any of us about car aerodynamics that to think otherwise is to be completely deluded.

I am currently (ie this morning) working with a suspension expert as I write a book on the history of car suspension. He knows so much more than I do about suspension that, even if I spent every minute between now and when I die studying suspension, I could never catch up. So yes, I am indeed happy to be guided by experts suggesting ideas. And you can be sure that in every case, they will have plenty of evidence to support the ideas they suggest - otherwise, they wouldn't have suggested them.

[freebeard]

For example, I would never, ever suggest how solar race teams could do better.

Not even it you frame it in the form of a question?

'Why don't [solar race] cars capture the 88% of solar energy rejected by the PV cells limited [in area] by class regulation?'

I wonder if the sky is blue above my house today because someone is holding up a big blue sheet?

duckduckgo.com/?q=goethe+color+theory

[kach22i]

Originally Posted by JulianEdgar

It's a nice idea but I basically never see it occurring on web discussion groups relating to car modification. What I do see is that many people like to see themselves as part of that process, I think because it makes them feel good about themselves. ("I am not just contributing mindless garbage but I am actually helping Fred!")...........

Originally Posted by JulianEdgar

........... So yes, I am indeed happy to be guided by experts suggesting ideas...........

Between these two posts is a gap of sorts, and I say that because we can call these two things separate or one in the same.

Basically, when it comes to car repair and modification, if someone has done it before then they are an "expert", if they have not, then they do not know of that which they speak.

Problem is some of those repairs have been done wrong, and some people know enough though other experiences that they don't have to try a bad idea to know it's bad.

I will say that I have personally seen car projects and repairs developed and proceed for the better and tragedy adverted via Internet bulletin boards/discussion forums.

However, I have also seen really bad advice given and criticism dished out, and when that critical person is asked "then what is the solution?" they have nothing and go on to the next person to annoy.

It's a mixed bag of nuts, never know what you are going to get.

List of things I would not be able to do on my own (without a forum):

1. Backside valve adjustment.
2. Re-index my ignition distributor.
3. Set my timing.
4. Find air leaks.
5. Fuel pump
6. Alternator
7. Accumulator (trickiness in bracing/turning)
8. Fuel filter (trickiness in bracing/turning)

The list is really long, this is only a partial list.

List of modifications I would not be able to do on my own (without a forum):

1. Remove points and install magnetic igniter system.
2. Remove 200-300lbs from car (where the low fruit is).
3. I have a list of mods to do, early design input gathered via forum (Pelican Parts - 911 Porsche - vintage).

[JulianEdgar]

Originally Posted by kach22i

I will say that I have personally seen car projects and repairs developed and proceed for the better and tragedy adverted via Internet bulletin boards/discussion forums.

Yes, common and well-proven mods on specific cars are often well covered on discussion groups. Same with common maintenance issues for specific cars.

I was referring more to 'ideas-based' mods i.e. stuff that is new or unusual. That's what I thought you were referring to when you said:

I am always amazed by humans, one person knows one thing, another knows another and somehow progress is achieved. Like ants building a massive ant hill.

With modifications that haven't been done before, I often think that people in discussion groups think the above quote is true, but I have very rarely (probably never) seen it.

[AeroMcAeroFace]

Originally Posted by JulianEdgar

If you reduce the effective weight of the car by half through aerodynamic lift, you will decrease the unloaded car's suspension static deflection by half. If the car has a static deflection of (say) 3 inches, and you have 50 per cent lift, the car will ride 1.5 inches higher. That will increase CdA, and may well in fact cause further lift.

(The opposite happens when you lower a car* - Cd, CdA and Cl all tend to decrease. *Road cars, with normal ground clearance.)

Adaptive suspension