adventures in flat plate land

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dog

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Dec 29, 2019
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A recent job is having aerodynamic repercusions,and as there is interest in similar projects I will ask for input.

The "mobile axe throwing lanes" I built for clients,#1 is 10' tall,8 wide,and 16' long.During the initial design,I said "thats going to pull a lot of air" crickets,then "gona want to go easy or its going to eat a lot of fuel" ... crickets. Second unit is even bigger ,12.5' x 8' x16' both units are completely flat on all sides and were built on existing flat deck trailers.

The client has now contacted me that.the trucks (full sized) are "struggling", and have heard back from the driver that they are getting well under 10mpg on the road.

But now I have another request to design a mobile photography studio,that must accomodate tall people, and be pulled by an SUV,and the client has mentioned a concern with wind,and getting blown around on the road. As this will be a scratch build, and will not need to contain thrown axes, I can build much lighter and take into account aerodynamic effects on fuel efficiency and handling.

Having validated the awsome drag generating capabilities of a flat plate,I am hopeing to get paid for something that demonstrates various drag reduction methods.

Dog
 
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TFF

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Apr 28, 2010
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17,658
Location
Memphis, TN
Usually the problem with trailers and aero is giving up space for the shapes or making it bigger to keep space but have the improvements.

I did have a friend with a homemade utility trailer that had a front like the bow of a ship using the hitch as the general guide. I had thoughts that it could be improved.

The nicest other purpose trailer I saw was a Vintage Airstream that was turned into a jewelry showroom. Completely gutted for new floor plan.
 

Hephaestus

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Jun 25, 2014
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YMM
nasa has some box truck wind tunnel testing reports. That's where those flip out air dams at the back doors come from, and funky molded trailer fairings ahead of the rear wheels.

Even that half round nose cone that kind of looks like a reefer - but is just a fairing - makes a noticeable difference.
 

proppastie

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Feb 19, 2012
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NJ
hope you have good liability insurance ......design and build of over the road hardware can be very dangerous......
 

dog

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Dec 29, 2019
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743
thanks for the links and anecdotes
wish I had pushed harder for making the
mobile axe throwing lanes more slippery
thinking about following the basics
build a "prow" of some kind
keep the outside as smooth as possible
make it as low as possible
put the wheel wells inside the box and to the
rear,fender skirts(with dzus)
arch the top and possibly give it
a tear drop shape as only one end has to
realy tall(front)
use a goose neck hitch and raise the tounge to keep from dragging in a hollow and with the wheels to rear it can be supper low and not ground out backing up,also will negate the need for steps if it works out.
looking at all the newer bumper hitch travel trailers as well
and,not worried about litigation,home built trailers
are made,bought and sold every day,in this case
they are for buisiness and have special liability insurance,I get signed off,and the department of transpo,gives a data tag,there is a police check
and a yearly saftey inspection,this is canada ,nothing gets done without the government getting involved in as many ways as possible
 

dog

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Joined
Dec 29, 2019
Messages
743
Does Canada have "loser pays both sides legal fees" like Europe?
no,but if you realy need to spend money on lawyers in canada,I suggest something to do with real estate
you can scratch build a one seat race car in canada,and get it road legal
heavy jet pilot who sold me some extra rivit guns
is building one,all aluminum,only one government
engineer in NB who can pass them regionaly,but
hey, its canada,kinda like a whole other country
 
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