Aerodynamic trailer plans

Member designs created in Sketchup or other cad program

Aerodynamic trailer plans

Postby jimbo69ny » Mon Oct 15, 2018 5:56 pm

Hello,

I am planning on building a lightweight aerodynamic teardrop to pull behind my all electric Toyota Rav4 EV.

I dont know how to use CAD (nor do I have the software) so I did the best I can sketching this out on paper. Please let me know what do you think.

Do you see any issues with the design that will become troublesome in construction?
What do you think of the idea?
Anything I should add?

I am not sure how the rear should hinge. I am thinking that the rear most section, after 8', could hinge up or to the side. I am open to suggestions.

Thanks!

Image

Image

Image


UPDATE: Version 2....

Image

Image

Image

Image

Image

Image

Image
Last edited by jimbo69ny on Mon Oct 29, 2018 8:20 am, edited 1 time in total.
jimbo69ny
Teardrop Master
 
Posts: 118
Images: 10
Joined: Thu Aug 09, 2018 2:53 am

Re: Aerodynamic trailer plans

Postby jimbo69ny » Mon Oct 15, 2018 7:04 pm

My motivation for the rear of my teardrop is the rear of semi trucks with the wind deflector. Its better for aero. Here are examples.
https://www.google.com/search?q=tractor+trailer+rear+wind+deflector&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjFxLfz24neAhXrT98KHRHmCesQ_AUIDygC&biw=1238&bih=681

I wanted to round the roof a bit to also help aero.

Lastly, I wanted the front of the teardrop to be flat so my wife and I can lean up against it when we are park if we want to sit and read a book or play with our baby. 36" is perfect. That leaves the overall height within my slipstream from my Rav4 too.
jimbo69ny
Teardrop Master
 
Posts: 118
Images: 10
Joined: Thu Aug 09, 2018 2:53 am

Re: Aerodynamic trailer plans

Postby Pmullen503 » Mon Oct 15, 2018 7:59 pm

I would make the whole Kam tail swing out sideways. Unless there is enough height at the roof junction to make a useable galley with the hatch up.
Pmullen503
The 300 Club
 
Posts: 458
Images: 58
Joined: Sun Nov 23, 2014 1:33 pm
Location: Fond du Lac, WI
Top

Re: Aerodynamic trailer plans

Postby jimbo69ny » Mon Oct 15, 2018 8:26 pm

Is there a good place to buy the parts to make it swing sideways? Just starting out so forgive me if there is some awesome trailer parts website that I dont know about.

Has anyone else done a side swinging rear door?
jimbo69ny
Teardrop Master
 
Posts: 118
Images: 10
Joined: Thu Aug 09, 2018 2:53 am
Top

Re: Aerodynamic trailer plans

Postby troubleScottie » Mon Oct 15, 2018 9:14 pm

There are several threads in here on this topic. I have not seen anyone suggest or build the rear deflector -- even on a square back design.


The teardrop profile is possibly the optimal shape as it presents good flow over the trailer. A brick shape is the worst. Wedges somewhere in between.

For any object, the biggest issue is the projected cross sectional area. Ideally the towing vehicle (TV) cross section is equal to or greater than the trailer. Due to the space between the TV and the trailer, the trailer often behaves like a separate object. Your trailers height might be less than the TV which is good, depends on your wheel size, axle placement, etc

Your upright front face may be the least than optimal. If you want a panel to rest against, you might consider a bulkhead inside the trailer. Of course given the 8' length, this might be impractical.

Also, the wheels are sources of drag. They might stick out relative to the TV, and present drag

BTW, 36 inch is pretty short. Given a mattress (2-6") and ceiling (1-3"), the usable height is cramped. Think about sitting under your desk. You might consider a taller design. A whole plywood sheet on top of the trailer bed will give you an additional 12 inches.


The other thing is to consider the materials that you are constructing this out of. Foam is the lightest. Plywood, etc can get quite heavy.
Michael Krolewski
Scottish Terrier Fancier
troubleScottie
Donating Member
 
Posts: 239
Images: 11
Joined: Sat Apr 11, 2015 5:02 am
Location: Seattle, WA
Top

Re: Aerodynamic trailer plans

Postby jimbo69ny » Mon Oct 15, 2018 9:25 pm

Thank you for your post!

I forgot to consider the thickness of the mattress when considering the height! Thank you!

I do plan on having the overall height and width slightly smaller than the Rav4.

Do you think I should curve the roof like I have in the plan? It really would be so much easier NOT to but I want to make it right. From what I have read and seen it is better to have the top/edges rounded off.

I googled it and the edges are a source of 6% of the overall wind resistance of a trailer.
jimbo69ny
Teardrop Master
 
Posts: 118
Images: 10
Joined: Thu Aug 09, 2018 2:53 am
Top

Re: Aerodynamic trailer plans

Postby Pmullen503 » Tue Oct 16, 2018 7:58 am

The compound curved roof will shed water better and be stiffer than a simple curved roof. So theoretically you can build it lighter. You have to ask yourself if it's worth the time and effort to get small increases in efficiency. My trailer costs about 10% on my gas mileage at 70mph. It's a cargo hauler with a big flat back end. Not very aerodynamic. But it's hard to justify building a better trailer when it only costs an extra penny or two per mile to bring it along.

Functional features should be your priority, then making that as aerodynamic as practical.
Pmullen503
The 300 Club
 
Posts: 458
Images: 58
Joined: Sun Nov 23, 2014 1:33 pm
Location: Fond du Lac, WI
Top

Re: Aerodynamic trailer plans

Postby jimbo69ny » Tue Oct 16, 2018 8:23 am

Pmullen503 wrote:The compound curved roof will shed water better and be stiffer than a simple curved roof. So theoretically you can build it lighter. You have to ask yourself if it's worth the time and effort to get small increases in efficiency. My trailer costs about 10% on my gas mileage at 70mph. It's a cargo hauler with a big flat back end. Not very aerodynamic. But it's hard to justify building a better trailer when it only costs an extra penny or two per mile to bring it along.

Functional features should be your priority, then making that as aerodynamic as practical.



I drive and will be towing with an electric vehicle. So to us it is very important to increase efficiency. You can refill in 5 minutes at any gas station. It would take me 45 ish minutes at a fast charger (which are still kinda rare).

So thats why I need to make it as efficient as possible.
jimbo69ny
Teardrop Master
 
Posts: 118
Images: 10
Joined: Thu Aug 09, 2018 2:53 am
Top

Re: Aerodynamic trailer plans

Postby tony.latham » Tue Oct 16, 2018 10:11 am

Camp-Inn says that their Raindrop model gets better mileage than their traditional teardrop-shaped model. You might PM those on this forum that have built raindrop shaped campers.

I noticed a difference when I went from a 4-wide teardrop to a 5-wide. Some of that was probably weight. (But I won't be going back to a 4'-wide.)

:thinking:

Tony
User avatar
tony.latham
Gold Donating Member
 
Posts: 3842
Images: 17
Joined: Mon Jul 08, 2013 4:03 pm
Location: Middle of Idaho on the edge of nowhere
Top

Re: Aerodynamic trailer plans

Postby swoody126 » Tue Oct 16, 2018 10:12 am

your drawings are not at all unlike the CLC teardrop

https://www.clcboats.com

here is a link to videos of it

https://www.bing.com/videos/search?q=cl ... &FORM=VDRE

like the concept waiting to see how you proceed

sw
"we are the people our parents warned us about" jb
swoody126
The 300 Club
 
Posts: 441
Joined: Mon Feb 22, 2016 6:11 pm
Location: north of Ft Worth
Top

Re: Aerodynamic trailer plans

Postby DaddyJeep » Tue Oct 16, 2018 12:19 pm

I have read this article a couple times during my designing. There are some interesting facts in here. It appears that the leading edge of your trailer is far more important that the trailing edge.

https://www.nasa.gov/centers/armstrong/ ... -DFRC.html
My big hybrid toy hauler with lots of curves build viewtopic.php?f=50&t=69618

155894
User avatar
DaddyJeep
Teardrop Master
 
Posts: 127
Images: 25
Joined: Sun Nov 19, 2017 5:30 pm
Top

Re: Aerodynamic trailer plans

Postby Pmullen503 » Tue Oct 16, 2018 2:04 pm

jimbo69ny wrote:

I drive and will be towing with an electric vehicle. So to us it is very important to increase efficiency. You can refill in 5 minutes at any gas station. It would take me 45 ish minutes at a fast charger (which are still kinda rare).

So thats why I need to make it as efficient as possible.


In that case, I'd think about rounding the leading edges of the trailer, keeping the underside smooth, and reducing the aero drag of the wheels if they'll be outside the body.

In my own case, I know just by watching rain through my back window (and the dirt patterns on the trailer itself when I tow through rain) that the airflow between the trailer and TV is chaotic. That has to be a major contributor to the total drag. So cleaning up that in any way will help.
Pmullen503
The 300 Club
 
Posts: 458
Images: 58
Joined: Sun Nov 23, 2014 1:33 pm
Location: Fond du Lac, WI
Top

Re: Aerodynamic trailer plans

Postby jimbo69ny » Tue Oct 16, 2018 2:50 pm

DaddyJeep wrote:I have read this article a couple times during my designing. There are some interesting facts in here. It appears that the leading edge of your trailer is far more important that the trailing edge.

https://www.nasa.gov/centers/armstrong/ ... -DFRC.html


I will definitely read this article. However before doing so I have to say that the leading edge would be the front of the car. If I can minimize the gap between the rear of the car and the front of the trailer, the front of the teardrop isnt as important.

There was another thread here on this site that showed the different aero turbulence points but here is a link that also shows it.

https://www.teamrunsmart.com/articles/truck-smart/maintenance/july-2013/aerodynamics-101-streamlining-your-trailer
jimbo69ny
Teardrop Master
 
Posts: 118
Images: 10
Joined: Thu Aug 09, 2018 2:53 am
Top

Re: Aerodynamic trailer plans

Postby jimbo69ny » Tue Oct 16, 2018 2:52 pm

swoody126 wrote:your drawings are not at all unlike the CLC teardrop

https://www.clcboats.com

here is a link to videos of it

https://www.bing.com/videos/search?q=cl ... &FORM=VDRE

like the concept waiting to see how you proceed

sw


I do really like that teardrop but I want something larger. Also, it seems like a lot of work putting that kit together. I have read about fitment issues with the door too.
jimbo69ny
Teardrop Master
 
Posts: 118
Images: 10
Joined: Thu Aug 09, 2018 2:53 am
Top

Re: Aerodynamic trailer plans

Postby jimbo69ny » Tue Oct 16, 2018 2:58 pm

tony.latham wrote:Camp-Inn says that their Raindrop model gets better mileage than their traditional teardrop-shaped model. You might PM those on this forum that have built raindrop shaped campers.

I noticed a difference when I went from a 4-wide teardrop to a 5-wide. Some of that was probably weight. (But I won't be going back to a 4'-wide.)

:thinking:

Tony


Thank you but that thing is too heavy. I just checked out their site. Its over 1000lbs! I am looking to build one around 400-600lbs.

I think my body design is good but I am keeping an open mind. So if anyone can prove differently I am leaning towards my design.
jimbo69ny
Teardrop Master
 
Posts: 118
Images: 10
Joined: Thu Aug 09, 2018 2:53 am
Top

Next

Return to Sketch up designs

Who is online

Users browsing this forum: No registered users and 1 guest