Pickup truck aerodynamics

[aerohead]

Originally Posted by freebeard

Let the record show that an ephemeral Signature comment triggered this comment.

KNON made this list: gdhour.com/stations.html#other along with two stations in Eugene and two in Portland. Note the #other -- there appears to be a vast, subterranean network centered on NY State. gdhour.com/stations.html

Ontopic: Could a 55-gallon drum substitute for the captured vortex? On powered rollers for A-B testing?

If you did that, the 'boundary' of the drum's surface would induce the Magnus- effect, like the experimental ship 'sails', and all rifled bullets, and artillery rounds, creating lift due to the low pressure of the boundary layer, dragged around the circumference and acting against the oncoming flow.
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To simulate the bed vortex, you'd have to come up with some sort of horizontal version of what Dr. T. Theodore Fujita created in his lab. to study tornadoes. You'd have an all-air phenomena rather than a bounded system.
That would be fun!

[JacobLeSann]

Magnus effect is fun! Way before I even had a car or knew about drag reduction, I played with alternative ballistics. Arrows were expensive and incredibly easy to lose, so I stuck with marbles and steel ball shot. These don’t have good stability, but they were better than what my physics teacher would give them credit for. They’d travel in an arc, and to increase range you would increase your firing angle. That was essentially the limit on range.

My friends got into airsoft, and had high velocity/high RPM guns, while I didn’t really have either (no money). I would build crossbows, slingshots, etc and mess with the $50 hardware store pistols. Anyways, these guns shoot round, 0.20 gram projectiles at some pretty amazing distances, and use a “hop-up” system to do so. That system is an adjustable rubber pad right ahead of the firing chamber that puts back-spin on the projectile before it is shot down the barrel. Employing the Magnus effect, the projectile’s arc can be transformed into a flat trajectory or even an upwards climb. Neat stuff.


I love lurking old threads

[freebeard]

I've seen (or at least heard of) it's use for everything from sail boats to quad-copter drones.

[aerohead]

I believe that the 'Magnus effect' was originally observed with the 'KRUPP' artillery projectile, fired from a rifled cannon.
It would have been a state secret at the time. Classified. Involving another order of magnitude of sophistication in firing solutions to predict compensation for the spin-related 'lift'/ drift.
The Aberdeen Proving Grounds provided a subsonic-to-supersonic drag table for four projectiles in one of my reference texts, and the 'Krupp' ( 'soup-can ) projectile was one of the four listed.
Imagine a 'bullet' with a sub-MACH drag coefficient of 0.88!

[j-c-c]

Saw this in Albertsons parking lot 2007?

For all skillful metalwork the fabricator created here, not sure why the large shelf was included under the headlight vs continuing the same raked frontal panel all the way to the corner and a much-reduced shelf in its place?

[Piotrsko]

Probably some obscure state vehicle law regarding headlights. Cali had those.

[j-c-c]

This is what I was suggesting, I see little here to upset any legal restrictions.

[aerohead]

Originally Posted by j-c-c

Saw this in Albertsons parking lot 2007?

For all skillful metalwork the fabricator created here, not sure why the large shelf was included under the headlight vs continuing the same raked frontal panel all the way to the corner and a much-reduced shelf in its place?

All my noses have this. And they're all enclosed with Acrylic covers, until destroyed in hail storms.
Since these areas are within a favorable pressure gradient, with the boundary-layer essentially held in place by the attacking flow, the 'buckets' become 'filled' with dead air, with the outer flow just skipping over with the Prandtl surface of continuity ( phantom nose ).

[aerohead]

Originally Posted by aerohead

I'll start a list for p'up drag coefficients and we can add and update as new data becomes available.The Cds will be in descending order, from high to low
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*1987 Ford F-150 ....................... Cd 0.567 (est)
*JEEP Comanche.......................... Cd 0.55
*1973-87 Chevrolet C-10............... Cd 0.569-0.535
*1985 Mazda B 2000 .................... Cd 0.523
*2002-2008 RAM 1500 Quad Cab .... Cd 0.52
*2000 RAM 4X4 1500 6.5' bed ........ Cd 0.50
*1986 Mazda B 2000 .................... Cd 0.495
*2001- Ranger ........................... Cd 0.49
*1994-2008 RAM 4X4 ................... Cd 0.48
*2000 RAM 4X4 Club Cab (all models)Cd 0.48
*1982-93 Chevrolet S-10............... Cd 0.475
*1982-93 GMC S-15 ....................... Cd 0.475
*1988 Ford F-150 ........................ Cd 0.473
*2005 Dakota Quad Cab 4X4/4X2 ... Cd 0.471
*2012 ISUZU D-MAX .................... Cd 0.47
*1987 Volkswagen Pickup .............. Cd 0.466 (est)
*2005 Dakota (all)......................... Cd 0.465
*1990 Volkswagen Tri Star Synchro.. Cd 0.46
*2000 RAM 1500 8' bed ................. Cd 0.46
*2000 RAM 3500 4X4 8' bed ........... Cd 0.46
*1988 Chevrolet C-1500 ................ Cd 0.45
*2000 RAM 3500 8' bed ................. Cd 0.45
*2004-2006 RAM SRT10 ................ Cd 0.45
*1994- Toyota T-100 ................... Cd 0.44
*1994-2008 RAM 2WD .................. Cd 0.44
*2006 Dodge RAM Mega Cab .......... Cd 0.44
*1990 Toyota pickup .................... Cd 0.44
*2000 RAM 4X2 Club Cab (all models)Cd 0.44
*2009 GMC Sierra HD .................... Cd 0.44
*1997 Dodge RAM 1500 ................. Cd 0.432
*1980s Dodge Rampage ................. Cd 0.428 (est)
*2008 F-150 Super Crew 5.5'bed ..... Cd 0.427
*1990 Volkswagen Projekt Zwo........ Cd 0.425
*1994 Chevrolet S-10 ................... Cd 0.42
*1994 GMC Sonoma ...................... Cd 0.42
*2009-12 Dodge RAM 1500 4X2 ...... Cd 0.419
*2011 Tacoma Pre-Runner off-road . Cd 0.419
*2011 Tacoma 4X4 0ff-road ........... Cd 0.419
*2009 GMC/Chev.XFE ................... Cd 0.412
*2009 F-150 Super Crew 5.5'.......... Cd 0.403
*2011- Ranger ............................. Cd 0.40 (A-pillars/C-pillars/lower air dam)
*2011 Tacoma Pre-Runner ............. Cd 0.394
*2011 Tacoma 4X4 ....................... Cd 0.394
*1997 Tacoma 4X4 V6 3.4L DLX ...... Cd 0.39
*2014 Toy.Tacoma (base) ............. Cd 0.39
*2010 RAM 1500 .......................... Cd 0.387 (200-hrs wind tunnel)
*2012 Dodge RAM 1500 4X2 ........... Cd 0.386
*2013 RAM 1500 Crew Cab SLT 4X4. Cd 0.376
*2009 Toy.Tundra ....................... Cd 0.37-0.38
*2007 Cadilac Escalade EXT .......... Cd 0.363
*1999-2004 Ford Lightning ............ Cd 0.36
*2010 Tacoma ............................ Cd 0.36
*2013 Dodge RAM 1500 4X2 ........... Cd 0.360 (lower dam,shutters,tonneau)
*2011 Tacoma 4X2 Reg Cab ........... Cd 0.357
*2011 Tacoma X-Runner ............... Cd 0.357
*1988 GMC Centaur (concept) ........ Cd 0.325 (est)
*2009 Mitsubishi Triton .................. Cd 0.32
*1989-90 GMC Syclone LSR ............ Cd 0.315
*2013 GM/Holden VT Commodore Ute, Cd 0.309
Here are two pictorial drag tables I completed last night.I'll add these as things evolve.

* 2023 Tesla Cybertruck................... Cd 0.335 ( official Tesla Motors reporting )
* 2023 Ford F-150 Lightning............. Cd 0.3757 ( @ 93% of latest F-150 reporting )
* 2023 Canoo Pickup....................... Cd 0.33 ( official Canoo reporting )
* 2023 Rivian R1T........................... Cd 0.322 ( from Wouter Remmerie, AirShaper )[without active air suspension lowered to minimum ground clearance ].
* 2023 Rivian R1T........................... Cd 0.30 ( allegedly from Rivian, with truck at minimum ground clearance.
* 2024 Chevrolet Silverado EV.......... Cd 0.331 ( official GM reporting )
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These additions are in random order.

[JacobLeSann]

Wow! I haven’t checked up on this thread in a while. Great stuff aerohead!

From what I can surmise, it looks like the better results in this list all share a common feature: rounded noses. The RAMs, Commodores, Tacomas…They all have good rounding on the front end. The Syclone seems to be the one that stands in the way of this. Perhaps it outclasses them by excelling in other areas.

Once again, my mind is darting back and forth about a Ute.