93Cobra2771
East Tennessee
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Definitely wouldn't trade just to reap an aero reward. But if trading, and the aero reward is decent, would be likely to sway my opinion to aero if similar in price/floorplan/weight.
It does seem as if more of the fiberglass models are rounding the nose significantly.
Richard White
2011 F150 Ecoboost SCREW 145" 4x4
Firestone Ride-Rite Air Springs/Air Lift Wireless Controller
2006 Sportsmen by KZ 2604P (30')
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neva4get
NJ
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According to what I have read, the mpg increase is the same as that gained by installing one of those curved wind deflectors on the roof of a truck. None.
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zak21
CO
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Joined: 07/24/2011
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Yes it will make a difference. How much only true wind tunnel testing can tell but yes it can make a substantial difference depending on the design. Check out this NASA research http://www.sti.nasa.gov/tto/Spinoff2008/t_3.html
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t-smith
Findlay, OH
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The problem / solution isn't in the front of the TT. It is in the back.
The trailers with the biggest MPG improvement are those that have a rounded or tear-drop back.
What we don't see with our bricks in the back, is the turbulent air that is swirling directly behind our TT, causing drag. It's not the pulling the front through the air, it's the dragging a vortex behind our TT.
edit: in the NASA link that the post above mine has - check out the tabs on the rear that they were using to manipulate the air behind the vehicle.
2004 Dodge Ram 2500, long bed, 2wd, 5.7l HEMI, 3.73
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jmtandem
western nevada
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Quote:The problem / solution isn't in the front of the TT. It is in the back.
Ford's towing guide suggests a take down for frontal area from their tow ratings. In the case of the full size pickups they suggest using about 60 square feet. How much higher the TT or FW sits above the truck would be the incremental difference (the truck's aerodynamics are basically fixed).
As the speeds increase up to about 40 mph or so with all other things being equal that they never are (wind, grades, geometrics, alignment, pavement conditions, other traffic and altitude) the power/fuel is used to overcome rolling resistance due to the tires, RV weights and inefficiencies in the drive trains). That is why tire pressures are important. After about 50 mph most of the incremental power increases needed combats wind resistance. Airstreams have an aerodynamic front and back that combines to give them their slippery wind resistance shape; that is their benefit gains are over square box trailers.
As I understand this, the difference to the RV user is essentially do you want to travel at 63 miles per hour with the aerodynamic trailer (front and rear, not just front) or do you want to travel at 60 mph with a trailer that is not aerodynamic. The power/fuel results will be the same. It is about how much power is needed to move the RV down the road. We can control the power/fuel usage and wind resistance differential by modifying not our RV loans but our travel speeds and that difference is very minor to get to the same results. And under 40 mph the aerodynamics of the trailer contribute little to the power needed to overcome rolling resistance; therefore, the real benefits are at freeway speeds.
'05 Dodge Cummins 4x4 dually 3500 white quadcab auto long bed.
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t-smith
Findlay, OH
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jmtandem :
Yes. I suppose I worded my reply quite definitively.
The frontal area makes a huge difference in towing. I was trying to point out that making the rear more aerodynamic (instead of only the front) will have a large impact.
I've always wanted to try AirTabs. They are designed to create controlled vortexes to help reduce drag. Anyone use them? I imagine they could help a little, but I can't see them making my flat backed more aerodynamic to the point of saving 1-2mpg
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skipnchar
Topeka or somewhere else
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Minimal at best. Remember that with a V nose you will ONLY get full effect when wind is directly ahead and wind coming from just OFF of the nose will actually hit a flatter front than it would on a standard front trailer. With the traditional trailer the wind would be striking the trailer front at ABOUT the same angle as a V nose with head on winds.
2011 F-150 HD Ecoboost 3.5 V6. 2550 payload, 17,100 GCVWR -
2004 F-150 HD (Traded after 80,000 towing miles)
2007 Rockwood 8314SS 34' travel trailer
US Govt survey shows three out of four people make up 75% of the total population
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93Cobra2771
East Tennessee
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For the purposes of my question, lets assume calm day. Otherwise, no amount of aero improvements will help agains crosswinds.
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t-smith
Findlay, OH
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skipnchar wrote:Minimal at best. Remember that with a V nose you will ONLY get full effect ...
I have to admit - I was surprised when I started towing a travel trailer. I tow about 12 times a year a 3 horse bumper pull trailer (V nose). Empty about 3500lbs - then add 3 - 1200lbs horses = 7100lbs.
My first TT was a 18' box, 3800lbs loaded. My truck (at that time) had a much harder time with the TT than the horse trailer - even though the TT was lighter. I was amazed at the difference of the wind resistance of a giant wall behind my truck.
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t-smith
Findlay, OH
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93Cobra2771 wrote:For the purposes of my question, lets assume calm day. Otherwise, no amount of aero improvements will help agains crosswinds.
My TT (see below) has a curved front. I had towed a friends TT of simalar size, but old (with a more flat front) - and I thought that mine was easier to pull. The weights were about the same.
But, that is just my opinion.
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