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Re: Foamie aerodynamics.

PostPosted: Tue Apr 10, 2012 2:07 am
by mezmo
Hi all Foamlings,

This is a cross reference posting for some Aero thoughts and ideas I drew
up last summer for Mojave Bob's Dreamliner proposal. I was having computer
problems and couldn't scan and post to a file and thus be able to post from
that back then. Anyway, I can now do that again and since I just came across
the drawings again that I did for the planned post then, I decided to post
it all now.

Here's the original Dreamliner thread link:

viewtopic.php?f=55&t=45633

Here are the two drawings I did. The explanation narrative for
them is now in the above thread. Just click on the pics and they will come
up larger. "CTRL +" will magnify them then if desired. "CTRL -" will back the
magnification down if you magnify too much with "CTRL +".

The Taper Draw-Up:
90555

The Foamie Plan and Side View Draw-Up:
90556

Cheers,
Norm/mezmo

Re: Foamie aerodynamics.

PostPosted: Tue Apr 10, 2012 5:31 am
by GPW
Norm, looks pretty sleek ! Should slip through the air pretty easily ... Like a fish through water ... :thumbsup: 8)

Re: Foamie aerodynamics.

PostPosted: Mon Apr 16, 2012 12:38 am
by atahoekid
GPW wrote:Norm, looks pretty sleek ! Should slip through the air pretty easily ... Like a fish through water ... :thumbsup: 8)


Hydrodynamics...aerodynamics. Pretty similar stuff, ain't it? :thinking: :thinking: :thinking:

Re: Foamie aerodynamics.

PostPosted: Mon Apr 16, 2012 5:23 am
by GPW
The air is just a thinner fluid ... :o

Re: Foamie aerodynamics.

PostPosted: Mon Apr 16, 2012 3:26 pm
by KCStudly
Figure out a way to apply fish slime (that thing that makes fish slippery) and you would really have something! (...but now I have to shoot you. :MLAS :whistle: )

Re: Foamie aerodynamics.

PostPosted: Thu May 31, 2012 12:49 am
by mezmo
Hi all Foamlings/Foamanistas,

This link isn't to a foam based TT as we think of it, but it is of a
related construction as they use composite panels that are foam
cored in their non-wood based construction. But, the reason I'm posting
the link is for the body design that uses aerodynamics applied to a
basically rectangular body design. Notice the front shaping and the rear
shape and tapering.

An amazing Australian Off-Road RV manufacturer:
http://www.kimberleygroup.com.au/4wd_camper
They make off road campers [tent trailers to us] and
now also two types of off-road caravans. We all need
to be able to rough it this way !!! [They are high end,
but they look to me like the highest value received for
the money.]

The newest product from Kimberley Kampers,
The Kimberley Kruiser:
http://www.kimberleykruiser.com/

Their first caravan, a telescoping hard walled unit, also with
aero applied to its body. The main idea here is to keep the
trailer[caravan] body within the tow vehicle's cross-section
and in [matching its] track width.
The Kimberley Karavan:
http://www.kimberleykaravans.com/

Again, great inspiration for home builders, at least for me.

Cheers,
Norm/mezmo

Re: Foamie aerodynamics.

PostPosted: Thu May 31, 2012 11:00 pm
by atahoekid
I love those Kimberley Kampers and had forgotten about them. I really like the unique look. I had looked at them before but didn't realize they are foam cored composites. If I build again, I am thinking about going truly composite just like these. I sorta went hybrid on this one. Thanks for bringing this back up for consideration. :beer: :beer:

Re: Foamie aerodynamics.

PostPosted: Fri Jun 01, 2012 5:54 pm
by SteveW
Those are awesome! If I had that kinda coin lying around, I'd definitely consider one.

Re: Foamie aerodynamics.

PostPosted: Fri Jun 01, 2012 8:01 pm
by GPW
http://www.kimberleykaravans.com/images ... 50x150.jpg

this looks good as is, un folded... for a LOW Foamie :thumbsup:

Re: Foamie aerodynamics.

PostPosted: Mon Jun 04, 2012 12:13 am
by loaderman
Wonder why the front doesn't go all the way down but has a storage box? Can't be better aerodynamics.

Do like it though.

Re: Foamie aerodynamics.

PostPosted: Mon Jun 04, 2012 7:45 am
by GPW
You know, when considering aerodynamics for a trailer (a box essentially) , you can’t get away from the profile drag , the cross sectional area presented to the wind... So that’s sorta “fixed” . The nose entry is probably the Most important element in smoothing the flow of air over the “Profile”. Ideally a fat smoothly rounded shape , practically for us , more Whale -like than “bullet”.. Rounding of the edges is key to a smooth flow. Easy with foam , as you can always add foam “fillers” under the basic structure to allow much more aggressive Rounding of the nose edges...
There comes a point where Practically bumps heads with Aerodynamics .....fer’ instance.. a fully rounded “Roswell” may look Slippery to the wind, but may not have the Inner space configuration for our needs (the BEER) :lol: ... when you severely round “the box” you lose a lot of interior ... :o So naturally the tendency in such cases is to go BIGGER ... but then you have a larger PROFILE :shock: ... the law of diminishing returns... You just have to do what You thinks looks and WORKS correctly for your needs ... :roll:

Re: Foamie aerodynamics.

PostPosted: Mon Jun 04, 2012 8:53 am
by linuxmanxxx
Most important is merging with and staying in the aero profile of the tow vehicle. You get outside of that vehicle created wind tunnel and rounding and shape won't help much with mileage results.

Re: Foamie aerodynamics.

PostPosted: Mon Jun 04, 2012 9:23 am
by GPW
True Dat !!! Like race cars “drafting” ... :thumbsup: Image

Re: Foamie aerodynamics.

PostPosted: Sat Jun 16, 2012 7:20 am
by GPW
OK, here’s another idea for a really streamline TD, with wheel fairings and underbody flow smoothing ... and it’s got a galley too ... 93611

Re: Foamie aerodynamics.

PostPosted: Sun Jun 17, 2012 5:45 am
by angib
Here is a graphic I did a long time ago about the best shape trailer I could think of to achieve low drag behind a Honda CRV:

Image

And here is a trailer that Honda themselves made to go behind an Insight. It is integral with the car and the bodywork is joined with flexible panels that allow it to steer. By adding the trailer (and also spats on the car's front wheels) they got the drag coefficient Cd down from 0.26 to 0.12 - that is a reduction to 54% less than the car alone.

Image

Minimising the gap between the car and trailer is important, though less so if the gap between the two is realistic for practical considerations like turning and negotiating dips/crests.