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Guess My Mileage Mini Round - Kardboard Kammback II Answered

Okay... I've got a 2 hour highway trip.... Same stats as before... except some aero modification :P I've done something unspeakable to my car... At least it looks a bit more like a kammback :p Looking from the front -- this adds no additional frontal area... So we'll see in a few hours if this helped at all :D Take a crack at it... I'm about to go fill up, grab some lunch and hit the road. Yes, you can still see the brake lights and you can still see out the back windscreen ;) I'm about to hit it with a permanent marker with some stats about my mileage :p And no, it doesn't damage the paint :p AND the radio still gets reception -- even though the antenna is held down like that :D

Discussions

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Weissensteinburg

11 years ago

What about seeing the blinkers from other lanes?

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trebuchet03Weissensteinburg

Reply 11 years ago

My current tail lights have visibility from the side... But my car has side markers in the front ;)

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acantinetrebuchet03

Reply 11 years ago

Have you considered using signal flares? Just a suggestion, take it or leave it. But you have to admit, it'd be totally awes.

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westfw

11 years ago

Interesting idea. Drag has multiple components that are usually munged together into an oversimplified "coefficient of drag" that one plugs into your equations to get an estimate of actual drag. For model rockets (where I learned most of my aerodynamics), you have frontal drag (proportional to forward-facing area), surface drag (area with parallel airflow), and base drag caused by read-facing area. Making your rocket "streamlined" seems to consist mainly of shaping things in ways that cause surface area that would have been part of frontal or base drag into surface area that contributes to surface drag instead. I don't know if your modifications will be successful at that or not... It'll also be interesting to see if the tape holds up at highway speeds...

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trebuchet03westfw

Reply 11 years ago

The tape held pretty good... I had some problems with the low pressure you get when passing a semi truck though :p My grille was also blocked off to make sure the stagnation zones are outside of the engine bay (so it could bleed off the front easier). My wipers were also lowered below the hood line (don't know why that wasn't done from the factory). I also removed my mud flaps and pulled in my mirrors when cruising. Lastly, my tires are pumped up to... well, lets not go there (I'm in a rather large group of people doing that - with one failure on an already damaged tire) :p I didn't post a picture -- but I took a picture head on -- this thing doesn't provide any additional frontal area... But that's not to say the effective cross sectional area didn't change. Really, the only accurate way to test this (at least more accurate) is A-B-A -- after/before. And verify with my fuel meter (scan gauge). The tail wind alone could have caused that fuel economy gain :p

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canida

11 years ago

Wow. What's the return mileage update?

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trebuchet03canida

Reply 11 years ago

Almost forgot to post :p

Return trip.... Also driving not very efficiently to keep up with others in my group:

34.61 -- the kammback was modified such that the top portion of the top section was removed.... To have to vertical panels and then the bottom bit was left alone. My thinking was to keep high velocity/low pressure air out of the dirty zone on the windscreen.


Here's the awesomeness....

On the way home (Orlando to South Florida - 200 miles). I had the kammback on for about 80 miles (then rain tore it apart). And I had a record tank (driving very efficiently).

39.2mpg!

Mother nature was on my side (sorta). That tropical storm was providing a nice tail wind... So the results are not "repeatable" (I guess that's not a result then :p). Mind you, the NEW EPA estimate highway is 31mph :D

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ewilhelm

11 years ago

Awesome! Now you need to make the whole setup inflatable so you can engage it while on the highway, but deflate it for tight, parallel parking!

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trebuchet03ewilhelm

Reply 11 years ago

Wow Eric... You have read my mind.... I actually want to talk with you and the people at squid about applying inflatable kite tech to such an idea :D Inflate only for higher speeds -- deflate for lower speeds and stop/go traffic et. al.

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acantine

11 years ago

sweet merciful jesus.... ...I don't know whether to bow or curse. Personally, I'm a big fan of the "it's easier to apologize than ask permission" mentality, but just for curiosity's sake, how many moving violations do you think you might be charged with in your eventual arrest? Good luck and Godspeed, Bandit.

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trebuchet03acantine

Reply 11 years ago

but just for curiosity's sake, how many moving violations do you think you might be charged with in your eventual arrest?

Zero -- I can still see out the back... Other drivers can still see my brake lights, signals etc. Even the third brake light is visible....

I actually spoke with an off duty cop at a gas station... He was rather interested. I told him that I hoped I didn't get pulled over... He said he was state trooper and checked my lights... and said no problem :) That made me feel much better.

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acantinetrebuchet03

Reply 11 years ago

*drums fingers* ...yes......excellent........

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trebuchet03

11 years ago

Well... my scangauge is on the fritz for some reason... I need to sort that out... But... the answer is (according to the gas pump)..... 35.5 driving like a madman because my sister's graduation was earlier than I was told o.0 My record is something like 36 driving slowly and efficiently on the highway. I reconfigured for the trip home... So we'll see how that worked out when I fill up next :p

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Stercus Fit

11 years ago

You've done some pretty crazy things but this definitely tops the list. I'm sure glad *I* don't have to ride in that thing. ;)