DIY hitch-mounted boat tail on Audi A2 3L (photos)
 

Found out about this Audi + tail from an inbound link to my thread about the Blackfly's prototype boat tail.

An Audi A2 forum was reacting to this vehicle:

http://www.a2oc.net/forum/attachment...5&d=1309774028

Did a Google search of the text on the side of the tail, which led me to a Netherlands web site documenting the build: aerotail

http://www.cathelijne.nl/images/priv...5052011142.jpgEDIT: the tail builder has joined EcoModder and posted a thread here: http://ecomodder.com/forum/showthrea...2-18413-2.html

http://www.cathelijne.nl/images/priv...5052011146.jpg

http://www.cathelijne.nl/images/priv...8052011153.jpg

http://www.cathelijne.nl/images/prive/tail/img_0871.jpg

More photos & info (you'll have to Google Translate it, unless you read Dutch) here:

aerotail

I like their analysis:

and general description (Google translation):

Wow, I really like this. It looks decent. The build quality is quite good.
You hear that?...
It's the sound of gears turning.

Hmmm.

I could so DO THIS.

I have the need (Trips out west in my future). I have the skills. I have the tools. I don't have the materials, but that can easily be remedied.

I should do this. I must.

Looking forward to the build thread. :)

It's surprising to see people bash something that gets better fuel efficiency. I guess i'm too used to ecomodder.

Well, that looks a lot smarter than a car-top box - and smart is pretty in my book.

If it were built and marketed as storage enhancement first, and aero/economy enhancement second, it might be more acceptable to the naysayers.

Looks like it could use some better gap management, but I like it. A lot.

considdering the A2 already has an 0.25Cd ! one can only imagine what the Cd of this combination must be. plus the fact this is esentially a cargo box makes it legal where permanent extentions would not be

Metro, THANK YOU for the link:thumbup: This is the kick in the ar$e I need to get my mods going again (and legalizing, see below).

Have you contacted the owner? I'd like to see a few more construction details covered, maybe in a new thread? If you like, I can write them a message since I'm interested in how to legalize this in Europe (the license plates suggest it is legal).

I followed a link and noticed a page about an aero'ed e-motorcycle, which I thought I'd seen before (EM?):
e-motion

That A2 forum is hilarioushttp://ecomodder.com/forum/member-pi...13-rotflol.gif
But should I be laughing at them when they are already laughing at us? Feedback loop, feedback loop, feedback loop, ...

Same here, only...
I have the need (car used mostly for long trips with friends). I can find the materials and tools. I only partially have the skills, but I'd be more than happy to remedy that:D

And here is my problem: making it legal. Polish parliament has been too lazy to pass laws allowing the use of rear-mounted cargo carriers, so it is illegal here to mount anything that covers the registration plates, and it's also illegal to take your plates off and transfer them to the bikerack/cargo carrier, even if it was designed for it (and legal in other European countries). Go figurehttp://ecomodder.com/forum/member-pi...re2536-grr.gif http://ecomodder.com/forum/member-pi...-brickwall.gif http://ecomodder.com/forum/member-pi...661-censor.gif
Gotta find a way around that.

what about laws regarding trailers? i'm sure they must have some regulations for them (and perhaps the fewer the better).

what i'm thinking is if you add two wheels to the tail and perhaps some other things to place it in the legal definition of a trailer, (without being one)
if you'd ever get into some legal trouble because of the contraption, and you can prove it's legally a trailer, they can't do much. bit of a silly idea perhaps, but if lawmakers fail to be creative you must :)

I have been planning to build a similar cargo box, delayed by a boatbuilding project. I really want the extra 10% FE. If I build a cargo box and add a killswitch, I think I could get 20% by EOC as much as possible. With my car, I think I could reach 60 mpg. For a while I was thinking about selling my car and going without a car, but I really enjoy driving through the country and seeing the sights so I think I will do what I can to increase FE. I like it that I could get better mpg than a lot of motorcycles out there.

There are two methods that I have been thinking about:
1. Plywood stitch and glue - this is a boatbuilding technique using epoxy and thin plywood. I would use the thinnest, lightest plywood I can get from Menards. This would result in a squared off cargo box.
2. Insulating foam - find an adhesive that will glue foam (PL Concrete and Masonry Sealer?). Get sheets of insulating foam and cut them to shape. Use screws to screw and glue the sheets together. Do some minor shaping with an orbital sander.

The frame of the cargo box would be a simple "T" of 1-1/4" steel square tube. I already have one made up. Then bolt on a piece of 3/8" plywood as a base, and the rest of the cargo box is fastened to the base.

I may build one to open up and actually use for cargo but I don't want any weight that far back so I don't expect to use it for cargo. I rarely fill my trunk, I have more space than I need. If I need to haul something big, I use a bigger vehicle. It is probably easier to just build a box that doesn't open.

Because of the reaction I got from my previous tail, I would label the thing "CARGO" with large letters. Even if it did not open up to hold cargo. just to minimize the hassles of rubberneckers.

I would add handles on top and skids on the bottom to make it easier to install and remove. Even if this reduces aero a bit, it will make it much easier to deal with.

I don't think cargo carriers are legal here either. We are allowed an extension of no more than 4 feet, but it does not specifically permit a cargo carrier. The extension law seems to have been written in a way that would suggest someone hauling long pieces of lumber would be OK if it didn't hang out more than 4 feet.

Are the cops in Poland that picky? Can't you get away with stuff? Here, most people ignore the laws, at least the details of the law. There are very few cops around here in the countryside.

If you follow the rules for a trailer (lights, registration) it seems you should be able to confuse the law officers enough to just use it and get away with it.

The termination of the tail reminds me of a bulkhead in a small airplane.
That combined with his construction style makes me wonder if he is a plane builder/restorer ?

Looks marketable to me. Might not use the aluminum skin though. Maybe ABS?

IANL but they sure do sell lots of cargo racks around here.
The 4' rule is important for safety reasons.

Intersting! for a while now I've been thinking about whether I could make something sort of like this to hang off the tailgate of my pickup. I hadn't even thought about using the hitch receiver.

Of course, I still don't have time to make it...but why should that stop me from thinking about it :D . Plus, I still have to build my aero-cap! Baby steps...baby steps

I wonder why he didn't pt some sort of dor on it and seal it completely. There was mention of limited cargo space and how the boat tail could be used to add cargo room. I think that is the definition of win win. Go on a trip, bring all your stuff and get awesome highway mileage. It would be interesting if it caught on with the public because of the dual functionality.

Haven't contacted anybody.

I bet he knows Allert Jacobs, who made the super streamlined ICE-powered motorbike. If you look through Allert's site ( Allert ), you'll see they even share a few photos of the comparison of upright vs. recumbent rider position.

There are even a few buildings in the background that look the same.

I wonder if they work together at a velomobile shop...

First build the boat, then the boattail?;)

Not yet, or at least I've been lucky. The only attention from police is when they take pictures with their phones:rolleyes: Even when I got stopped for speeding the policeman didn't say a word about my mods. Though I have noticed that when I pass a patrol one of the policemen usually has a "WTF?!? I wish I'd stopped that car!" expression on his face. Then I check in my mirror if he's fired up and chasing me for a second look, but no luck, yet.

It's the yearly inspection which is a potential problem, either because the inspector wants to solicite a bribe, or b/c he's afraid that if I get into trouble then the authorities will easily see which inspection station OK'ed me.

EDIT: Maybe I should register my car in Ukraine, where technical inspections have recently ceased (in an effort to stop the widespread bribery between inspectors and car owners)?

That's actually a good idea, but trailers have their own set of can&cannot laws, which may include a minimal distance between the trailer itself and the rear of the car. On the other hand, I doubt that any law specifically states that a trailer's wheels must be in contact with the ground at all times... Though I probably won't get away with just painting wheels on the sides, so there will be a weight penalty for the wheels.

It's that comparison photo which turned on a light. Those guys doing great!:thumbup:

Back on topic, this A2's aerotail just reminded me of Bondo's Box

Another way to possibly attach this to a hatchback and still get access to the hatch, would be to use extending slides (like drawer slides) on the underside and have a latch release to move away from the car.

Crossposting
My Aerotail on Audi A2

http://wwwm.coventry.ac.uk/researchn...%20Vehicle.pdf

Good test documents on drag reduction

Have seen some softpack rear carriers on the road but a hitch-supported boxes looks so much cooler. http://ecomodder.com/forum/showthrea...html#post95597

Cd 0.288
 

So if the production car comes in at Cd 0.288,and the tail nets a 10% improvement in HWY mpg,then that's a 20% drag reduction,and 0.8 X 0.288= Cd 0.23.
If the integration of the tail to the A2 was tighter we might expect to shave a little off that number.

I think that if something for car or car itself is legal in one EU country, it must be legal for rest of EU countries, but of course in practice it might not be so happy situation, might need to go into court and fight to EU court until EU says that yes Poland must comply to EU legislation.

We have similar issues too, but here is more with taxes and such.

Maybe such should be possible here, to make small boattail, that would boost my economy quite a bit for sure, might even get to 3l/100km with such :D

I added a curt basket to my car and while testing my F/E "hit" that I expected I actually saw a gain!

It's this model CURT Manufacturing | CURT Manufacturing - CURT Cargo Carrier #18140.

I choose this one because it curves up a bit to get it out of the air flow and it also adjusts front to back to get it as close to the bumper as possible. It's still very easy to load the trunk. I also got it at about half the price listed there.

I got about .5l/100 better of 6.1 to 5.6. I did 3 runs to and from work with it, then took it off and saw my tank avg increase after 3 more runs to and from work. Put it back on for the rest of the tank. Next tank took it off for the first 3 runs then put it on and saw the avg drop. It's been on every since. In the summer I may play with smoothing out the bottom and sides with coroplast and using plati dip to stop the sun drying it out. I won't touch the top though so that I can still use it for it's intended purpose. It really came in handy when I picked up the xmas tree, so far the only time it's been used for it's original purpose.

One downside is most of the rubermaid boxes I see are listed as about 1in too wide to fit, however they mostly taper so I'm hoping that when I actually try one it will fit down at the base.