| [GMCnet] AERODYNAMICS [message #362197] |
Thu, 04 February 2021 11:45  |
Oliver Moore
Messages: 21
Registered: March 2018
Karma: 1
|
Junior Member |
|
|
I just returned from a two-day drive on I-95 (in my car). It struck me that
most of the long haul trucks had a variety of wind deflecting
devices--front air dams, long panels between the wheel to reduce air under
the trailer, and curving shields over the rooftop AC. Has anyone tested if
any of these would improve our MPG? I have two rooftop storage units, for
instance. It would be easy to make a deflector to lessen air resistance--if
it would improve mileage.
Oliver
'74 Glenbrook
Patterson Stage II engine
Alcoa wheels
Honda generator
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
|
|
|
|
| Re: [GMCnet] AERODYNAMICS [message #362198 is a reply to message #362197] |
Thu, 04 February 2021 12:53  |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
|
Senior Member |
|
|
Search airtab.com. Due to the curved rear cap on the GMC probably less gains. Might help on trailing edges of rooftops etc.
John Lebetski
Woodstock, IL
77 Eleganza II
|
|
|
|
| Re: [GMCnet] AERODYNAMICS [message #362203 is a reply to message #362197] |
Thu, 04 February 2021 15:51 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
|
Senior Member |
|
|
Before the accessories go on, the coach is very aerodynamic. Resistance is roughly the same as the corvette of the area, drag coefficient of about .3. Of course, .3 times the area of the thing is a fair amount to push through the wind. JI wouldn't be looking for any great mileage gain though. Jimmy the K's degree in in aerodynamics, he might could help you.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
|
|
|
|
| Re: [GMCnet] AERODYNAMICS [message #362206 is a reply to message #362203] |
Thu, 04 February 2021 16:39 |
 |
Richard RV
Messages: 631
Registered: July 2012
Location: Full-timer for 12 years, ...
Karma: -17
|
Senior Member |
|
|
I don't recall (paging Bill Bryant) if the drag coefficient of ~0.3 was for the 1/8 scale model, but it was for a naked GMC - no mirrors, no wind wings, no rooftop AC, vents, pod, roof rack, door hinges, awnings, etc. With all of that stuff I don't have a clue what the GMC's coefficient would be, nor how it would compare to any other RV. It's a good bragging point, though. 
Richard
'77 Birchaven TZE...777;
'76 Palm Beach under construction;
‘76 Edgemont waiting its turn
|
|
|
|
| Re: [GMCnet] AERODYNAMICS [message #362211 is a reply to message #362206] |
Thu, 04 February 2021 18:26 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
|
Senior Member |
|
|
You would be well served to insure your tire pressures were on the high
side of correct, keep your loaded weight as low as possible, drive 55 mph.
Keep your engine well tuned-up, and install the EBL Fuel Injection with a
re-curved distributor that was matched to your final drive gearing. Also,
be sure that you have no brakes dragging, and your wheel bearings are
freshly packed and properly adjusted. That should account for 3 to 5 mpg
better mileage.
Jim Hupy
Salem, Oregon
On Thu, Feb 4, 2021, 2:39 PM Richard via Gmclist
wrote:
> I don't recall (paging Bill Bryant) if the drag coefficient of ~0.3 was
> for the 1/8 scale model, but it was for a naked GMC - no mirrors, no wind
> wings, no rooftop AC, vents, pod, roof rack, door hinges, awnings, etc.
> With all of that stuff I don't have a clue what the GMC's coefficient would
> be, nor how it would compare to any other RV. It's a good bragging point,
> though. ;)
>
> Richard
> --
> '77 Birchaven TZE...777;
> '76 Palm Beach with 18,477 verified miles;
> ‘76 Edgemonte
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
|
|
|
|
GMCforum
Search
Help
Register
Login
Home
