| Anyone use AIRTABS [message #294871] |
Tue, 02 February 2016 06:28  |
skip2
Messages: 544
Registered: September 2011
Location: Winter Haven,FL (center o...
Karma: 3
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Just saw an advertisement for AIRTABS on the monthly link to the FMCA, anyone ever tried them, mostly interested in getting rid of the semi-truck and crosswind problems it claims to help with. Wouldn't take to many at 3 per foot and $2.75 each. Or is it just more snakeoil?
Skip Hartline
74 Canyon Lands, FiTech,
3.7 FD LSD, Manny Tranny,
Springfield Distributor,
2001 Chevy Tracker Ragtop Towd
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| Re: Anyone use AIRTABS [message #294883 is a reply to message #294871] |
Tue, 02 February 2016 07:57  |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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skip2 wrote on Tue, 02 February 2016 07:28Just saw an advertisement for AIRTABS on the monthly link to the FMCA, anyone ever tried them, mostly interested in getting rid of the semi-truck and crosswind problems it claims to help with. Wouldn't take to many at 3 per foot and $2.75 each. Or is it just more snakeoil?
Skip Hartline
Skip,
Vortex generators have been around a long time. Their activity is well understood.
That type will do the most good when applied at a square trailing edge. We come real close to not having any of those. If you had a Winnieboxo, they might be worth considering.
I can pretty much bet that they will not change the truck bow wave or cross wind issues you might be having. For our coach, those issues were much improved by getting the front end right. The truck "bow wave issue is still there, but it was much improved.
I bet JimK knows more about them than I do and I would love to hear what he knows and thinks.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: Anyone use AIRTABS [message #294886 is a reply to message #294871] |
Tue, 02 February 2016 08:39 |
TR 1
Messages: 348
Registered: August 2015
Location: DFW
Karma: -7
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My understanding of VGs is that they help keep air affixed to a surface when it would normally depart which causes drag, and in the case of an aircraft wing: loss of lift. These are often used in STOL (short takeoff and landing) kits... You'll see them on bush planes, etc.
I would think that if the air can stay affixed to the rear curve of a GMC, it ~may~ reduce drag, but only sure way to tell would be in a wind tunnel.
At $2.75, each, I would probably pass, but most of the VGs I've seen on aircraft are just right-angle bent pieces of aluminum riveted to the skins in a chevron pattern.... That would cost very little in materials and might be a fun project.
Do some research on the proper angle and location of the tabs... Or maybe some experimentation... I've seen where before wind tunnels, people used dollops of washable paint placed on the surface of the skin, then go out and drive/fly, whatever. The wind would create a streak that could be used to determine air path over the surface, and should be able to show where the air is currently departing the surface of the motorhome...
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX
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| Re: Anyone use AIRTABS [message #294893 is a reply to message #294871] |
Tue, 02 February 2016 10:19 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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skip2 wrote on Tue, 02 February 2016 05:28Just saw an advertisement for AIRTABS on the monthly link to the FMCA, anyone ever tried them, mostly interested in getting rid of the semi-truck and crosswind problems it claims to help with. Wouldn't take to many at 3 per foot and $2.75 each. Or is it just more snakeoil?
Skip Hartline
I've spent considerable time with them and my opinion is that for the average person like us--they are a waste of time. You need to accompany their use with extensive airflow tools that most of us don't have. They are great for aircraft and automotive manufacturers that have sophisticated wind tunnel resources. Without those, it's a total crap shoot and a waste of money.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: Anyone use AIRTABS [message #294897 is a reply to message #294871] |
Tue, 02 February 2016 10:49 |
skip2
Messages: 544
Registered: September 2011
Location: Winter Haven,FL (center o...
Karma: 3
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Also just hit me that most of us have 2 vertical 1" pieces of aluminum at the back left, also known as awning support, in the way of airflow so it would probably just kill off any good it might be able to do. I'm sure 2 AC units and a pod and a visor on the front don't help. Well maybe the visor does, any thoughts on that?
Skip
74 Canyon Lands, FiTech,
3.7 FD LSD, Manny Tranny,
Springfield Distributor,
2001 Chevy Tracker Ragtop Towd
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| Re: [GMCnet] Anyone use AIRTABS [message #294958 is a reply to message #294918] |
Tue, 02 February 2016 23:05 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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All I can say as a degreed Aerospace Engineer is that these devices can
help I F you can apply it in a correct manner.
I have an rough idea as to where it an help our coaches, but I would need
to consult with my buddy that plays with these things and have practical
experience.
On Tue, Feb 2, 2016 at 1:04 PM, Robert Mueller
wrote:
> Bob,
>
> Agreed!
>
> I did some web surfing and could not find ANY video's of actual wind
> tunnel testing, the only thing I found was computer generated
> "cartoons" (I used that word deliberately) showing before and after:
>
> https://www.youtube.com/watch?v=f80a9jssUFU
>
> Regards,
> Rob M.
> The Pedantic Mechanic
>
> -----Original Message-----
> From: Bob de Kruyff
>
> I've spent considerable time with them and my opinion is that for the
> average person like us--they are a waste of time. You need to
> accompany their use with extensive airflow tools that most of us don't
> have. They are great for aircraft and automotive
> manufacturers that have sophisticated wind tunnel resources. Without
> those, it's a total crap shoot and a waste of money.
> --
> Bob
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: Anyone use AIRTABS [message #294962 is a reply to message #294871] |
Wed, 03 February 2016 02:02 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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I think I'll order 3 of them and put them on my pineblock derby coach. I need something to beat Laurie with.
Naw, they will have to wait until I finish with the diesel upgrade.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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