First Aero-Cap Maverick?

[narclepticfool]

Hey all!

I just recently got my 2023 Ford Maverick. I wanted a small truck, but didn't want to sacrifice fuel efficiency, so this seemed like the ticket (and also it wasn't $100k electric truck, which would have been sweet!). Because I tow all the time, I needed the 4k tow package, which meant I could not get the hybrid. The 2.0T Ecoboost is rated 24/29 mpg, which for a little non-hybrid truck is pretty good. I recently went on vacation with my family and needed the extra space for camping gear, so took the Maverick. To make sure I had covered/lockable storage, I threw together an Aero Cap. This is iteration 2, as the first aero cap build I did was for a 2009 Toyota Tacoma (profile pic, I4, 2WD, Manual trans). I learned a lot from that build and the longevity issues with how it was constructed. I also learned that the aero cap on that truck was good for +4-5 MPG.

Long story short, on my ride down to the Cape, I was doing 65-75mph fully loaded, with a hitch carrier and got 31.8MPG. I would say that this aerocap is useful, but maybe not as easy to hypermile as the Tacoma was because its an 8 speed auto with no manual control. Also, I know, 75mph is not a hypermiling speed, but the fact that I was able to exceed the EPA highway mpg estimates fully loaded, and well above the EPA testing speeds, means the cap is doing something!

[freebeard]

It would be interesting to see the cap off the vehicle. To see the internal framing.

v2.5 might be capping the frame with half-round tubing to soften the edge.

[narclepticfool]

Ill get some more picture of that.

What do you mean about adding 1/2 round tubing to soften the edges? Does that improve the aero even more?

[freebeard]

You can ignore that. I really can't see enough detail to know what I'm talking about.

[cRiPpLe_rOoStEr]

HAve you never considered a full-lenght boat-tail which could also serve like a bed extender with the tailgate down?

[aerohead]

Originally Posted by narclepticfool

Ill get some more picture of that.

What do you mean about adding 1/2 round tubing to soften the edges? Does that improve the aero even more?

1) you've converted a 'notchback', to a 'fastback,' and fastbacks are the most sensitive body type to 'tumblehome' and edge radii influence, because of vortex-related drag issues.
2) Baron von Koenig - Fachsenfeld tested 'fastbacks' specifically for this tumblehome/edge radii effect, and registered 16% lower drag, when the side-to-top intersection was 'softened.'
3) It requires 'compound' curvature. which is the most labor-intensive shapes to fabricate, and scares off all but the hard-core streamliner.
4) And the lack of plan-taper in the truck box mandates degree of compromise, as one would literally have to discard any OEM truck box, and start from a clean sheet of paper ( or CAD ).
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5) another observation about your trip mileage. There's a likelihood that the receiver hitch cargo carrier was acting as a crude boat tail, filling the void which would ordinarily be nothing but turbulence.
MOTOR TREND did an extended A-B-A road trip with a Pacifica and cargo carrier, and while reluctant to attribute higher mpg with the carrier, did experience higher mpg with it, compared to without it.
6) Member, Brett Herndon, of Littlerock, Arkansas, created a patented 'Aerolid', and 'aero tail' for the 2012 model F-150. His tail was good for delta Cd 0.031 in the wind tunnel.

[freebeard]

2) Baron von Koenig - Fachsenfeld tested 'fastbacks' specifically for this tumblehome/edge radii effect, and registered 16% lower drag, when the side-to-top intersection was 'softened.'
3) It requires 'compound' curvature. which is the most labor-intensive shapes to fabricate, and scares off all but the hard-core streamliner.

This is what I was getting at at Permalink #2.

[aerohead]

Originally Posted by freebeard

This is what I was getting at at Permalink #2.

Yes, thanks!
I constructed a dedicated graphic from Fachsenfeld's book, but lost it, along with about 770 other images when Photo-Bucket was sold to pirates. I'll never recover from that.

[narclepticfool]

Thanks for the clarification on the rounded edges. And yes, I know a full boat tail would be better, but I need it to be functional for daily contracting and family use. Not sure I could get a full boat tail to manage that.

As to the hitch carrier acting like a crude boat tail, I agree that is likely a possibility. I did another trip recently without the hitch carrier, and only got 30.5 MPG, or there abouts, and with similar speeds. I did go into the mountains though, rather than toward the coast, so that could have had something to do with it. It does give me an idea that maybe I should play around with a hard sided hitch carrier box thats more streamlined for when I do need more storage space. It might achieve a boat tail add on function and added space. If I do, I'll keep you all posted.

I also added a few more pictures so that the structure is more evident. I also added gas struts today so the lid lifts and doesn't require a prop stick.

[freebeard]

Notice the step of 2-3" abaft the cab. You can use everything else and just replace the triangular fluted plastic pieces.

As a first approximation you want 4% of the gross width as a radius (aerohead?). That's something less than 4".

You have a big advantage with the single box cab/bed design. Those black plastic edge protectors might be a foundation to work from.