MetroMPG's Honda Insight boat tail extension (cardboard) tuft video; ABA test +9.7%

[AndrzejM]

Great result! Congrats! I wish I could build a boat tail for Berta... But that's impossible here in Poland.

[MetroMPG]

I bet an aero trailer isn't.

[pascal28]

Bloody good job!! Thanks for sharing the results of such a rigorous test!

What was the distance travelled in your runs?

Also, do you think it is worth filming a tuft test on the underside of the boat-tail? It would be great to get some test support on what angle works there.

[ECOHondaOdyssey]

Excellent work!

[MetroMPG]

Hi, Pascal: test route is straight, level and 1.6 km/1 mile "at speed" (not counting the distance used to get up to speed & level off, coast down and turn around etc). You can see the section of road I use here: along the shore of the mighty and lovely St Lawrence River, immediately to the southwest of where that map link is centered.

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I plan to tuft test the bottom of the tail. The car needs a full belly pan for the bottom of the tail to work well. I'm sure it's in very turbulent flow now, but a full undertray will feed it some cleaner flow to work with. It's on the list!

[Blue Angel]

Very nice! Glad to see the work paid off with great results!

[pRoy]

Your cardboard skills are on another level! Looks so amazing!

Decided to take a brake from my Vanagon project to check out some eco love!

Let me know if you want coroplast. Also near the top it was mentioned Aluminum composite panel would be a good product to make this out of. I have some ok sized scraps laying around you can have if you want to see what the properties are like.

Msg me if you need a camera man to follow you! Would be happy to help out.

[wmjinman]

OUTSTANDING JOB, MetroMPG!!!!! I was all happy & proud of myself after filling up the White Gnat and seeing my first 54 mpg tank, but is that really 109 mpg you got with the boattail? - in "non-hybrid mode"?!?!?! Whoa - I gotta git me a first gen Insight!!!!!!

Again, WELL DONE!!!!

[jime57]

Interesting. I also looked at some quick and simple approach, but I also suffer from TMP. My only criticism is that I don't think I'd give away the improvement achievable from smoothing out the tail light area by relocating them, like you did on the metro. I think you will regret doing that. It isn't really all that hard to do. all you have to do is use a trailer harness with snap on taps just inside the hatch wiring.

I'm glad you aren't looking for the 15% you got on the Metro because I strongly suspect it isn't there on the Insight. The Cd is already too good.

[MetroMPG]

Originally Posted by pRoy

Decided to take a brake from my Vanagon project to check out some eco love!

Hey pRoy.... thanks for the offer to film. I need to keep that in the back of my mind. I sent you an e-mail on other topics.

Originally Posted by wmjinman

is that really 109 mpg you got with the boattail? - in "non-hybrid mode"?!?!?!

Yup - that's the beauty of light weight + good aero + tall gearing + the secret weapon: LEAN BURN.

Originally Posted by jime57

My only criticism is that I don't think I'd give away the improvement achievable from smoothing out the tail light area by relocating them, like you did on the metro. I think you will regret doing that. It isn't really all that hard to do. all you have to do is use a trailer harness with snap on taps just inside the hatch wiring.

No trailer harness or extra lights on hand made that approach less quick & less simple. The future better (and more complicated) version of the tail will take that approach though. Until then, I can happily live with ~10% better highway MPG.