Honda Insight Tail Extension Project

[3-Wheeler]

Originally Posted by aerohead

.... The boat-tails should help with that in a big way and it will be fun to finally hear the results after these add-ons make it through gestation.

Phil,

I have to say that reading all the postings of yours over the past two years, and hearing Mike from aerocivic talk about your affect on him at the 2009 Hybrid Fest in Madison, one can reach the easy conclusion that you have affected many people here at EcoModder in a very positive way!

We are all in this together and it's great to have your input and inspiration to help us in our individual projects that we post here.

Thanks for your input.

Jim.

[3-Wheeler]

Originally Posted by Varn

You are famous, cool beans....

I don't think of it in terms of being famous, and besides being famous is not really what it's cracked up to be.

But if one is passionate about something and really enjoys it, then "comes what may" may come true.

I really enjoy both reading and posting at this site. And that should really be enough, don't you think?

Jim.

[3-Wheeler]

Originally Posted by Weather Spotter

any MPG improvement data? I want an idea of what to expect if I make one

Weather Spotter,

I would have to say that so far, a 10% gain seems fair, but Metro's was closer to 15%, and both our cars are similar in aerodynamics overall.

I can give you a better idea after one solid month of coast-downs. That will be towards the end of November.

Also, I can understand your hesitation!! I felt exactly, and I mean exactly, the same way after reading Metro's exciting write-up on his tail extension. What would the Insight get after all this work? And a lot of work it was, since I really missed most of the summer while working on the car. I really like riding bicycle in the warm months and only went out once because of the tail, so it was a huge amount of work and sacrifice!

If someone knew ahead of time, maybe they could spread out the project over the winter and work on it in the basement with the snow flying outside. That would pretty cool in my estimation. But I knew from prior planning that the extension was too big to fit in my basement without making it in smaller pieces.

Jim.

[Weather Spotter]

The basement idea is a good one, but will not work in my case

10-15% was in the range of what I was expecting, someone one my idea thread thought I would get 20-30% which just seamed too high.

Any design guidance? I have to make a window in mine and will likely go the solid over built way. I put up some drawings of a rough shape, do they look right?

I might hit you up for some foam ideas as I want to use that to fill the gap from the structure of tue tail to the shape of my car. More on that when I get there.

[Piwoslaw]

Originally Posted by 3-Wheeler

We are having some work done in our office area by general contractors and one of them asked how much more fuel mileage I was getting. In otherwords, he could tell just by the shape that aero efficiency was the goal, but had no idea that the car can get close to or over 100 mpg. Most people guess about 50 or so for some reason.

This is probably b/c 50mpg is already astronomically high by many people's standards.

[3-Wheeler]

Originally Posted by Weather Spotter

....10-15% was in the range of what I was expecting, someone one my idea thread thought I would get 20-30% which just seamed too high.

I think what that person might have meant was, your total gain from the tail really will be 20 to 30%, but because rolling drag and air drag are equally split regarding affect on the vehicle, the aero benefit is cut in half, so you end up with an effective gain of 10 to 15% from the aero side of things.

Originally Posted by Weather Spotter

...Any design guidance? I have to make a window in mine and will likely go the solid over built way. I put up some drawings of a rough shape, do they look right?

Well one big piece of advise I can give is make sure your overall body shape matches the AeroHead template. I worked over these numbers with Phil quite a bit. Look on the following page for more info...

http://ecomodder.com/forum/showthrea...t-13533-8.html

That thread talks about the streamlining template quite a bit, so take a close look before making your final design.

Jim.

[RobertSmalls]

Originally Posted by 3-Wheeler

Robert, go for it! And contact me when you want to discuss working with foam more. We're all on this planet for one reason or another, and mine seems to be helping with foam of all things.

Jim.

Thanks, Jim. I won't be doing much with fiberglass until spring, but when the snow starts to melt, I'll give it a good, hard think and decide whether to start carving an Insight tail extension. In any case, hopefully I'll see you while I'm in Madison for Hybridfest 2011.

Perhaps I can give you a hand or some pointers on assembling a MIMA controller, too. I think it would go well with a boat tail.

[skyl4rk]

Originally Posted by 3-Wheeler

I think what that person might have meant was, your total gain from the tail really will be 20 to 30%, but because rolling drag and air drag are equally split regarding affect on the vehicle, the aero benefit is cut in half, so you end up with an effective gain of 10 to 15% from the aero side of things.

i meant that a good tail should increase the mpg by 20 to 30% above the EPA rating, without using any driving techniques. Driving techniques can easily add 20% or more on top of that.

If a car is rated at 30 mpg, one should see results of 36 to 39 mpg with the addition of a tail and no driving techniques.

Its just a rule of thumb, not a rule.

[RobertSmalls]

Skylark,

I would need an ~18% aero drag improvement to hit lean burn and achieve the magic 75mpg@75mph on flat ground in the summertime. That would be a 27% improvement over stock, with driving techniques that would make a hypermiler cringe.

[skyl4rk]

The more aero efficient the stock design is, the less increase you will see from a tail.