Truck aero help please

[aerohead]

Originally Posted by Piotrsko

the slant aero top would reduce rear traction or mess with the spoiler they have now.


Suspect they are traction limited as it is.

The aeroshell reduced rear lift on Spirit to 22-pounds @ 130-mph. 4220- pound travel weight, @ 50/50 weight distribution.

[Telco]

Got a question on the cab spoiler. Invariably, the studies I see show that the ideal angle for the spoiler is, tape a string to the top of the cab, then pull the string to about 6 inches before the end of the bed. This is for a 6.5 foot bed so I'm going to assume the angle is same for a bed that's a foot shorter, pretend the bed is 6.5 foot. If this is not a correct assumption I don't mind being corrected.

What I don't see is the ideal shape for the spoiler itself. Should this thing be rounded on the ends, a flat plane all the way across, should it stretch the full width of the cab or fall a couple of inches short on either side, how should this thing be shaped when looking down at it from above? I'm going to wind up making my own here. All I'm seeing for cab spoilers for my truck available for purchase are for the purpose of ricing it up, not for correcting aerodynamic shortfalls. Actually, that's all I'm seeing for any trucks, looks trumping all.

[freebeard]

I don't get the string falling short of the bed part.

Put little weathervanes at both rear corners and see which way they point at road speed. My suspicion is that the air is being pulled together and they will point outward. If so, then -- what? a 45 degree chamfer?

[Xist]

Originally Posted by freebeard

I dare them to take this camping!

[Piotrsko]

Been places where it could go camping, but might as well be lost wages casino camping for what's that worth

[aerohead]

Originally Posted by Telco

Got a question on the cab spoiler. Invariably, the studies I see show that the ideal angle for the spoiler is, tape a string to the top of the cab, then pull the string to about 6 inches before the end of the bed. This is for a 6.5 foot bed so I'm going to assume the angle is same for a bed that's a foot shorter, pretend the bed is 6.5 foot. If this is not a correct assumption I don't mind being corrected.

What I don't see is the ideal shape for the spoiler itself. Should this thing be rounded on the ends, a flat plane all the way across, should it stretch the full width of the cab or fall a couple of inches short on either side, how should this thing be shaped when looking down at it from above? I'm going to wind up making my own here. All I'm seeing for cab spoilers for my truck available for purchase are for the purpose of ricing it up, not for correcting aerodynamic shortfalls. Actually, that's all I'm seeing for any trucks, looks trumping all.

If you parked the truck on top of a really big mirror, and stood way back, 'seeing' what the air actually 'sees', the 'ideal' cab-wing contour would be defined, if you superimposed the ideal teardrop after-body onto the truck and it's mirror-image below the ground, from the peak height of the cab's roof.
It would also define the architecture of a proper rear spoiler.
It's exactly what Dr. Hermann Burst of PORSCHE did with the 911 in 1968.
Today's Hyundai IONIQ 6 does the same thing to help with its aerodynamically-incorrect roofline.

[Telco]

We've had a lot of rain lately, and what little time it's dry outside I have to spend maintaining my farm. But, I've picked up a flat piece of cedar scrap from the local feed store. I'll be starting with the underwing idea first as I'm still trying to work out how to temporarily mount a deflector to my bed cover without damaging anything or drilling holes. There are plenty of places to mount the underwing without damage though.

[kach22i]

Just to let you guys know, I tested out a large rear spoiler on my pickup truck.

https://forums.pelicanparts.com/off-...xperiment.html


It hurt gas mileage and felt like I was towing a large boat when on the highway, or like a giant child was squishing down on his toy car.

Ended up cutting it down in half, and it worked great.

EDIT:

If one misses the air attachment profile, you can go up with a ductail or out with a tea-tray.

https://www.reddit.com/r/Porsche/com...s_your_choice/


The concept below would be in clear/tinted acrylic or polycarbonate so that taillights could still be seen. The diagonal support kicker could be a lockable in position hinge or collapsible strut. And for added safety, a continuous LED light along the rear edge - always on and tied into the brakes.

https://ecomodder.com/forum/showthre...e-41767-2.html


EDIT:
If the Bonneville style rear extension was getting the cops attention then maybe large tufts in lieu of safety flags could be put on.

AI says:

If a load extends 4 feet or more beyond the rear of a vehicle, a red flag or cloth at least 12 inches square must be displayed at the extreme rear end of the load during the day. This flag must be visible to drivers approaching from the rear.