Silverado aerocap build thread

Airtabs, among other vortex inducers, are used primarily to organize airflow and promote laminar adhesion. Evidence indicates that they are also particularly useful in crosswinds as well. Vortex inducers are fairly easy to make, and though still in their infancy, can nonetheless produce considerable results. Obviously size, shape and placement are critical factors.


TS

[Frank Lee]

I requested evidence, not an advertisement

[ChazInMT]

I'm about to faint in terror and apprehension over just how incredible these "Air tabs" and "Other Vortex Inducers" might perform...Just imagine if we put them on a car or truck with golf ball dimples all over it? The dam thing would just push itself down the road with out using any gas, you'd spend a fortune on brake pads just keeping the thing from speeding down the road at 120 MPH all the time....heck, you could probably hook a generator up to one of your tires and charge your battery ta boot. (I suppose that mod wouldn't fall under "Aerodynamics")

What an incredible age we live in.

LOL, I get it, haze the newbie.


Without my own uber impressive personal victory data...Airtabs stink and I'm their personal schill boy.


Thank you sirs may I have another.


TS


P.S. I was going to share something really neato with this site, but you guys were....(sniff)....meanies! I hate you!

[mjboks]

Originally Posted by TechStuf

LOL, I get it, haze the newbie.


Without my own uber impressive personal victory data...Airtabs stink and I'm their personal schill boy.


Thank you sirs may I have another.


TS


P.S. I was going to share something really neato with this site, but you guys were....(sniff)....meanies! I hate you!

I think it'd be better to show proven results than to just say 'yeah these are great and the work'. There have been a lot of claims and people promoting vortex generators but no one has provided results that show they actually work (btw, a website saying they improve 4% FE isn't good enough). This site is all about what actually works and not just gimmicks. We like to see actual results like an A-B-A test that shows and improvement. For all that we know, you work for the air-whatever VGs and are trying to promote them. If you have something that is really neato like FE results showing improvement with those VGs then yeah, show us. Maybe start another thread since we've hijacked this one.

[Frank Lee]

Oh no, now we will never reach that stage of enlightenment. What a loss to humankind.

I think it'd be better to show proven results than to just say 'yeah these are great and the work'. - Mjboks

I understand where you are coming from. No doubt, personal experience is great, but I'm hardly interested in running a jaded gauntlet of those naysayers who will cast aspersion no matter the data... I courteously provided the OP a link to Airtab's site, at which a cursory perusal reveals meaningful results. If NASA's wind tunnel tests aren't enough for others, then my comparatively paltry and subjective data certainly wouldn't be persuasive.

Oh no, now we will never reach that stage of enlightenment. What a loss to humankind. - Frank Lee

It's not like I'm advocating pulstar plugs here, and as any EcoModder worth his salt already knows, aerodynamic efficiency gains are cumulative. No one addition or reduction is going to do it all. It's also common sense knowledge by now that a flat trailing surface creates a vacuum, which induces drag. By questioning the valid data already produced, that vortex inducers structure trailing edge flow, thereby lessening drag turbulence, one demonstrates ignorance.

Does the rear of a silverado truck end in a point? Obviously not. Would airtabs lessen drag at that location?


Well shucks, apparently that's a hog of a different hue now ain't it.



TS


P.S. My simple suggestion for the maker of the fine silverado aero topper to try airtabs is not responsible for any 'hijacking' of the thread. Topics grow, it's natural. And if by some nefarious chance sprinkling of pixie dust occurs and the OP should see some modest gains by addition of a few cheap airtabs, or his own versions, then I for one, could certainly see cause for a new topic.

[MetroMPG]

A-B-A evaluation of Airtabs at the rear of a GM minivan. No discernable change in fuel economy @ 55 mph:

http://ecomodder.com/forum/showthrea...fect-6381.html

Perhaps those wishing to beat this horse of undetermined vital statistics (VG's) could do so in a thread like that one.

[aerohead]

Originally Posted by TechStuf

I understand where you are coming from. No doubt, personal experience is great, but I'm hardly interested in running a jaded gauntlet of those naysayers who will cast aspersion no matter the data... I courteously provided the OP a link to Airtab's site, at which a cursory perusal reveals meaningful results. If NASA's wind tunnel tests aren't enough for others, then my comparatively paltry and subjective data certainly wouldn't be persuasive.



It's not like I'm advocating pulstar plugs here, and as any EcoModder worth his salt already knows, aerodynamic efficiency gains are cumulative. No one addition or reduction is going to do it all. It's also common sense knowledge by now that a flat trailing surface creates a vacuum, which induces drag. By questioning the valid data already produced, that vortex inducers structure trailing edge flow, thereby lessening drag turbulence, one demonstrates ignorance.

Does the rear of a silverado truck end in a point? Obviously not. Would airtabs lessen drag at that location?


Well shucks, apparently that's a hog of a different hue now ain't it.



TS


P.S. My simple suggestion for the maker of the fine silverado aero topper to try airtabs is not responsible for any 'hijacking' of the thread. Topics grow, it's natural. And if by some nefarious chance sprinkling of pixie dust occurs and the OP should see some modest gains by addition of a few cheap airtabs, or his own versions, then I for one, could certainly see cause for a new topic.

Tech,I'm going to throw my two cents in.
The air tab borrows from the turbulator,used in aeronautical work.
During landing of a tricycle landing gear aircraft,and at large angle of attack,the turbulator energizes the boundary layer,allowing function of the ailerons which might otherwise be embedded within turbulence and rendered useless,allowing a crashed airplane.
The turbulator is a constant source of drag but in the toatal energy balance of the entire airplane shows a net benefit to flightworthiness.
The most important thing to consider about the turbulator is that there is something BEHIND it.
If you place turbulators at the back of a vehicle,there is nothing back there for separated flow to re-attach to.
A Mitsubishi Lancer may benefit from tabs,as air will re-attach to the trunklid.
The pickup has no such structure behind it.
The other thing is,that with the new 2010 Lancer,you'll see that Mitsubishi has lost the notchback and has gone to the 'sportback',more like a proper Kamm roofline.Not great but better.
It seems like even they no longer want to play the separation/re-attachment game.
Those little tabs typically require a wind tunnel for sizing,number,and placement.They should be used as a last resort.

The most important thing to consider about the turbulator is that there is something BEHIND it.

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.

http://airtab.com/en/Product_Applica...ickups_30.html

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