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Old 08-19-2018, 09:24 PM   #742 (permalink)
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Join Date: Dec 2014
Location: Butte, Montana
Posts: 725

little jona - '91 Dodge D 250 first gen cummins LE
Team Streamliner
90 day: 23.4 mpg (US)

Little Jona airo modded - '91 Dodge RAM 3/4 TON D 250 24 AUTO
Team Cummins
90 day: 18.5 mpg (US)

The Salted Hound Jenny. - '87 Dodge Ram 50/D-50 5sp 4X4
90 day: 20.24 mpg (US)

Jona Allison aero - '91 Dodge Ram D-250 Le
90 day: 20.76 mpg (US)
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What is the reason for the "ears"? Redirecting flow toward the boat tail?
It is part of the functional design of the standalone headache rack/ long load carrying support to prevent damage to cab from ladders and long pipe.
I made a mistake matching the silhouette of the back of a cab, wound up being too short on the corners and dead even in the center(load sitting on cab sheet metal). So I added the flat 1:24 wing (24x longer than thick =1/8"3)with 3/16" positive camber(nose up) center 0 off horizontal, 3/8" pos. camber at the tips. The triangular supports mid-span are also set to approximately 10 to 15 degrees out of air flow travel direction ( would cause counter-rotating vortexes off of each leg of the triangle
All wings that produce lift have down wash. So yes the patch(wing) is designed to use the down wash to catch and mitigate the turbulence caused by the cab to canopy gap ( second thing the wing patch was the cab angles forward resulting in my ideal half inch at the base of a headache rack and 3.5" at the top).

It demonstrates what is happening in the wheel wells very nicely. At 0:03 and 0:51
Sorta. It would be better with the wheel rotating.
Yesterday 07:43 AM
agreed spin would be better . Best would be engine running at various speeds primarily Peak torque and Peak horsepower and a moving floor treadmill, while we're at it dreaming big put that treadmill on a turntable so we can account for crosswind interaction. wind is almost never straight on so the strate up wind tunnel testing only demonstrates about 2% of real world conditions primarily the Gorge between Bonneville Dam and The Dalles
1st gen cummins 91.5 dodge d250 ,HX35W/12/6 QSV
ehxsost manafulld wrap, Aero Tonto
best tank: distance 649gps mi 24.04 mpg 27.011usg
Best mpg : 31.32mpg 100mi 3.193 USG 5/2/20

'83 GMC S-15 Jimmy 2door 2wd O/D auto 3.73R&P
'79 Chevy K20 4X4 350ci 400hp msd custom th400 /np205. 7.5-new 14mpg modded befor modding was a thing
87' Hyundai Excel
83 ranger w/87 2.9 L FI2wd auto 18mpg on the floor
04 Mitsubishi Gallant 2.4L auto 26mpg
06 Subaru Forrester XT(WRX PACKAGE) MT AWD Turbocharged 18 plying dirty best of 26mpg@70mph
95Chevy Blazer 4x4 auto 14-18mpg
04 Chevy Blazer 4x4 auto 16-22mpg

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