Silverado aerocap build thread

[aerohead]

Originally Posted by TechStuf

I see that there is something behind the technology, and size, shape and placement are key factors. Airtabs certainly aren't the end all be all of drag reduction nor is anyone claiming such to be the case. They are, however, a good start in the right direction. 4% or more is worth it to some, not to others.

Autos & Pickups: Airtab

It seems pretty straightforward that structured airflow off the tailgate is better than having the airflow attach to the tailgate in the traditional chaotic manner with commensurate maximized drag losses. Also, considering the sizable pressure differential between the area just forward of the tailgate and center aft of the tailgate, I'm certain that there is much that could be gained by exploiting that difference. I am working now on a system which should generate a truly astonishing amount of energy from the pressure differentials otherwise being wasted on a vehicle moving at highway speeds. My test bed vehicle is an 89 Toyota xtra cab pickup.

Simply making a vehicle as slippery as humanly possible and calling it good is great for those who love the tradeoffs... and let's face it, land torpedoes are awesome eye candy! But there is also much (and this is an appreciable understatement) yet to be explored in the way of compromise between acceptable aerodynamics and energy capture.


TS

Techstuf, I feel like I'm missing the boat somehow.
You speak of 'generating'' energy',Do you mean to say that you are going to generate 'power' from the available energy?
If you harvest energy of the pressure differential between the front of the truck,and behind the tailgate you're doing nothing to reduce the engine load so your mpg will be unchanged.
Any machine you employ to capture energy will have a net overall energy loss compared to just streamlining the truck.
No doubt your study of thermodynamics and entropy have made that clear.
If we make vehicles as streamlined as humanly possible have we missed something?
The study of aerodynamics,within the context as we use it at EcoModder,deals with drag reduction and it's association to mpg only,not 'energy capture.'
Any attempt to capture energy would only degrade the quality of the flow field surrounding the vehicle,leading to increased drag and increased fuel consumption.Yes?

[swede]

In response to the conversation above regarding vortex generators on passenger vehicles.....

While I make no claims to being as knowledgeable as some of the senior members here, I can say with confidence that the first law of thermodynamics applies especially when considering road-going vehicles. If there was a way to create a vehicle that demonstrated over-unity characteristics with regards to energy in vs energy out i am sure that it would have made it's way onto this forum of all places and been tested ad nauseum.

I can however attest to the simple effects of a few simple aerodynamic improvements and the gains in efficiency that can seen. Vehicle manufacturers have little choice but to cater to the customer's demands when it comes to the styling cues that denote a vehicle as the "new" model. This more often than not leads to less than ideal aerodynamic and efficiency numbers.

Thankfully this gives us here a lot to work with and improve upon. I would feel very satisfied if I owned a vehicle that was ideal in all aspects, but alas, I fear that will never be the case in my lifetime, unless I do the work myself.

Swede

Any attempt to capture energy would only degrade the quality of the flow field surrounding the vehicle,leading to increased drag and increased fuel consumption.Yes?

Yes. All except for the words, 'any' and 'only'.


Careful study of the lowly Bacterial Flagellum reveals some amazing design considerations, as they employ virtually 100% efficient electric motors and propellers by which to effect locomotion.

http://www.youtube.com/watch?v=5I3f4OpT3_w

Notice the design and placement of their propeller filaments, particularly in the E Coli bacteria.



It's all there in nature. Everything. By design....the opportunities to reverse engineer what has already been created are mind boggling.


TS

[ChazInMT]

Tech stuff, you seem to buy into the idea that fairy tails are true. Here's one for you then, get this "Flagellum Drive" of yours all worked out, built and tested in reality, then I will personally be there to shake your hand in Oslo Norway when you collect your prize.

I hate to seem mean spirited, it's just that there is simply no reasoning with someone who lives in a fantasy land, so I won't bother. You put off the comments of Aerohed (Who is among the most respected people in the world of automotive aerodynamics) so nothing I could come up with can compete.

I post this message so that anyone who stumbles into this thread will maybe get the idea that you're sort of out there.

I will not respond to anything you ever say again.

Tech stuff, you seem to buy into the idea that fairy tails are true.

you're sort of out there.

I will not respond to anything you ever say again.

Well, that certainly seems sort of unreasonable. Considering that the lowly

Pistol Shrimp

has mastered some of the finer points of cavitation energy and sonoluminescence, I'd have hoped you could have cut me and my fairy tailed cohorts, the bacterial flagellum, a bit more latitude.

"There are more things in Heaven and earth, Horatio, than are dreamt of in your philosophy."

...then I will personally be there to shake your hand in Oslo Norway when you collect your prize.

And what a 'prize' it must be. I hear they don't give those things out to just anybody...

Al Gore wins Nobel Peace Prize - Climate Change- msnbc.com

http://www.nytimes.com/2009/10/10/world/10nobel.html

You put off the comments of Aerohed (Who is among the most respected people in the world of automotive aerodynamics)

A modicum of research reveals that there are plenty of aerodynamics to go around for everyone. My reticence at impaling my left ventricle with a cuff link or two in a forum to which I am, as yet, an uninvited visitor, should hardly be considered off putting. As I largely agreed with Aerohed, I would have hoped you could appreciate the difference between his being slightly put off, and roundly put down.

This forum is titled, "EcoModder", not '"EcoFodder", is it not?


Peace and Prizes,



TS

[Christ]

Just to clarify something -

The shrimpy dude, as well as bacterial flagellum, exist in incompressible fluids. Trust me - that helps.

They have to spend less energy to begin moving because the medium is already compressed. In air (back up here, where we drive) the medium isn't already compressed... this means that ALOT of energy has to be "wasted" to compress the medium so that it's density is correct to propel the vehicle through space. This has to happen at the same rate of speed (slightly faster, actually) that the vehicle wishes to progress.

Get in the water - now wave your arms quickly from front to back, while standing completely immersed. I bet your body moved, did it not? You could feel the drag of the water against your arms, driving you forward. Now do the same thing in open air. The only movement you feel is inertia from your arms' movement. The compressible air around you will flow out of the way before you can compress a column of it tightly enough to provide propulsion.

Hold a fish behind it's gills in water while it attempts to get away... most average sized fish will be able to either pull away from your hand, or force you to move as they do.

Do the same in air... that fish can't compress the air fast enough to do anything more than wiggle in your hand. It can't propel itself at all.

You can't directly compare things that exist in incompressible medium with those that exist in the opposite.

You can't directly compare things that exist in incompressible medium with those that exist in the opposite.

They are hardly opposites....merely dissimilar fluids. And as for our atmosphere not being compressed, I'm sure you are at least somewhat flexible on that one.

They have to spend less energy to begin moving because the medium is already compressed.

I think I hear you saying that water is an incompressible medium that is already compressed.

My video expositions are not meant to be 'direct' comparisons. Directional, perhaps, but certainly not direct....not at this juncture.



TS

[Christ]

clearly, you understand those concepts... I was clarifying for the sake of others, not as immersed in this field of study.

[ShadeTreeMech]

lessons learned from the world of fluid dynamics are universal, but water is much less dense than air, so anything extrapolated from water to use on land would have to be exagerrated to be considered similar.

Also, somewhere common sense should come into play, surely.

And aerohead has been doing this stuff while many of us were babies. He deserves respect by virtue of earning it.

[Christ]

Originally Posted by ShadeTreeMech

lessons learned from the world of fluid dynamics are universal, but water is much less dense than air, so anything extrapolated from water to use on land would have to be exagerrated to be considered similar.

Also, somewhere common sense should come into play, surely.

And aerohead has been doing this stuff while many of us were babies. He deserves respect by virtue of earning it.

Backwards, my friend. Water is on order of 800 times more dense than air.