why hasnt someone made the inflatable boat tail yet?

[Otto]

On, say, a van or Volvo wagon, I think it would be cheap and easy: Use Coroplast panels to extend the lines of the sheet metal aft, attached with duct tape, and with a self-inflating fabric panel to enclose the rear. Self-inflating like the shirt of a motorcyclist, which balloons out behind.

Actually, NASA already did this years ago with tractor trailers. The bag would self-inflate at speed, reducing drag in the process, but droop down when the truck slowed or stopped.

If you put, say, a bike rack on the back of a Volvo wagon, this thing would cover the bikes and protect them from the weather and road grit, while streamlining the vehicle at highway speed.

[BamZipPow]

Someone has made an inflatable boat tail...

Aerovolution...

[EVDRVR]

Originally Posted by BamZipPow

Someone has made an inflatable boat tail...

Aerovolution...

Nice, but from my reading on ecomodder it looks like that would be a much better front than back. Better than the blunt but wouldn't more length and less severe angles result in greater gains.

Of course a truck would be up against maximum length laws and they want the length devoted to payload.

[BamZipPow]

Originally Posted by EVDRVR

Nice, but from my reading on ecomodder it looks like that would be a much better front than back. Better than the blunt but wouldn't more length and less severe angles result in greater gains.

Of course a truck would be up against maximum length laws and they want the length devoted to payload.

It's not about the shape...but more of the technology and the materials.

[miket]

Originally Posted by Bicycle Bob

that wives would only veto because they look Too sexy?

Originally Posted by MadisonMPG

How much time/money do you have? That will be a big factor.

Pfizer the maker of the little blue pill could sponsor this project to eliminate aerodynamic dysfunction, they spend huge amounts of money on advertising and promotion. Turn the inflatable boatail into a billboard for them and drive in their commericals, do some publicity events and magazine articles etc.

[miket]

I was thinking of 2 ways to make boatails.

Take medium sized tubing, inflate it and then fold it back and forth like intestines a bunch of times, glueing the folded tubes together to form a boatail shape.

Make a boatail out of fabric then sew a huge number of threads between the top and bottom and the left and right sides to pull it to the correct shape. Im curious, how did they sew all the threads in the inflatoplane, long needles?? With something as big as a boatail it might be best to sew from inside. I was thinking bend 4 or 6 steel tubes to form the corners. Attach one end of the tubes to a support, maybe scaffolding, or a pair of bookshelves etc. Take the open vehicle end of the fabric boatail and slide it tightly over the curved corner tubes. crawl in the open end with thread and a needled and sew working backwards. When done disconnect the tubes from the support and pull them out one at a time. If the bottom side of the boatail is flat than this could be done directly on the floor or ground.

[round.boater]

Rafting companies already have the technology for strength needed of this application. My raft has a perfectly flat surfaced drop stitch floor that inflates to ~4psi and I can stand on it hardly making a dent. The issue is attachment to the back of the vehicle and cost. To get a high enough quality fabric, your pay-back time is going to be a bear. That's not to say I don't day-dream about this though...

[miket]

How do they do the drop stitching? Can they do that on structures that aren't a constant thickness??

Anything done by hand wouldnt have near that density of fibers.

How long would your payback be if you use a 1000 gal of gas a year? Attachment doesnt seem that hard. I have a hitch. I was entertaining adding some attachment points on the back of my flip up cap door to drop it onto.

Aerohead recommended a hinged flat bottom piece to add stiffness and keep the tail from flapping around as well as forming the bottom. I wonder if that raft material would work good for the bottom.

[euromodder]

Originally Posted by Otto

Self-inflating like the shirt of a motorcyclist, which balloons out behind.

Done that way, it'd add drag.

[Bicycle Bob]

Do you think self-inflated airfoil kites have high drag?