Boat tail mod to my enclosed trailer

[Otto]

Originally Posted by aerohead;1ques91311

I see no reason why the unit wouldn't be very light,unlike my Frankensteinian creation.
Home Depot has an ABS plastic garden pool as large as a trailer body which probably doesn't weigh 20-pounds ( 9-kilos ).Two of these would account for enough plastic to create an upper and lower clamshell.With 3/4-inch ( 19mm ) plywood decking,we're still talking under 250-pounds ( 113-kilos ).
The gap-fillers are yet an un-resolved issue,but mine are evolving nicely,just have to wait.There are certainly dozens of 'solutions' for them,just like automatic drip coffee-makers.
At some point,it's a no-brainer.

Plastic garden pool idea: Pool is round, radiused at edge of side to bottom?

Cut in half vertically, then use one half inverted to fair the upper forward roof of trailer, and then use the other half upright to fair the forward floor to leading edge wall?

PVC pipe might work to stiffen, frame the fairing?

[Braebyrn]

I was thinking what Bam said and I bought some led lights to install in the boat tail. I was hoping to get away with what is there and to keep it cheap, but really it could be more expensive when I get a ticket or worse get rear ended........ I could just hear it now..... Officer, I couldn't see the brake lights!!!!!

I can't find any Coroplast at Home Depots or Lowes in the Kansas area. Does anyone know where to get some? I am headed to Georgia, then to Chicago. Maybe a alternative to it?

Also, I am trying to figure a way in my mind how to build the nosecone with the Pvc and Coroplast. I also saw some cool looking clear curved basement window covers. They look like they could work for a deflector.

Thanks.
Rick

[Otto]

Originally Posted by Braebyrn

I was thinking what Bam said and I bought some led lights to install in the boat tail. I was hoping to get away with what is there and to keep it cheap, but really it could be more expensive when I get a ticket or worse get rear ended........ I could just hear it now..... Officer, I couldn't see the brake lights!!!!!

I can't find any Coroplast at Home Depots or Lowes in the Kansas area. Does anyone know where to get some? I am headed to Georgia, then to Chicago. Maybe a alternative to it?

Also, I am trying to figure a way in my mind how to build the nosecone with the Pvc and Coroplast. I also saw some cool looking clear curved basement window covers. They look like they could work for a deflector.

Thanks.
Rick

Sign shops sell Coroplast, so check Yellow Pages or Google online. Just out of the electoral primary season a few days ago, surely there are political signs to be had, although those are local scrounging endeavors more involved than a trip to any Home Depot or Lowes.

Why not do the front of your trailer just like the back, but orient the half-cylinder vertically? PVC pipe can be bent or bowed to semi-circular or elliptical shapes, is cheap and easy to cut and glue, etc.. I'd look into the plastic pool idea posted previously, for the upper and lower front intersections of wall to roof and floor.

Instead of PVC pipe, strips of wood lath from Lowe's would work for the frame. It should bend easily enough to the radius of the leading edge of your trailer, otherwise steaming the wood works great to make it bend to shape.

If/when I do a trailer, plan to try slicing wood strips into narrow enough pieces that will fit into the flutes of Coroplast, for protected internal stiffening where needed. A single 8' 2X4, sliced into thin strips, might suffice for most of your trailer fairing's forebody. Google for "geodesic canoe" or similar, and see how light and strong such structures can be.

[skyl4rk]

Cope Plastics Inc. - Distributor and Fabricator of Quality Plastics

[Frank Lee]

Forgive me...

I don't see how that rear end shape can improve aero substantially. The angle of the side pieces appears good but the top, bottom, and roundedness?

And the discussion about doing the same (same shape?) for the front = not good either. I think these things have been discussed in other trailer and semi/trailer threads here.

[Varn]

I once saw Steve DeLaire's trailer. It was a fairly small 2 wheeled trailer that was covered in aluminum panels. Looking down from the top it was tear drop. He claimed that he got several MPG better than when he was not pulling the trailer with his minivan. I only have one photo of it with the door open. It does not show the design very well.

[Otto]

Originally Posted by Frank Lee

Forgive me...

I don't see how that rear end shape can improve aero substantially. The angle of the side pieces appears good but the top, bottom, and roundedness?

And the discussion about doing the same (same shape?) for the front = not good either. I think these things have been discussed in other trailer and semi/trailer threads here.

So, he's better off to just leave it shaped like a brick with wheels?

Surely you jest, as this flies in the face of everything NASA, NASCAR, Hucho, Schlor, Hoerner, and various people on this website including the OP have been reporting, for decades.

I'll stick with my earlier suggestions, i.e., convert the front of the trailer to basically a rounded horse trailer shape, but with a teardrop or Kamm tail and faired wheels and belly. The extra weight will be inconsequential, but the cruise speed drag of both trailer and tow vehicle will be reduced significantly.

That's right: Proper drafting reduces energy used on both front and rear vehicle, regardless of whether they are connected mechanically by trailer tongue or not.

[Frank Lee]

No, he's better off making aero improvements. It's just that I don't see how that thing hanging off the back improves anything, and I don't see how your suggestions for the front improve anything either.

[Otto]

Originally Posted by Frank Lee

No, he's better off making aero improvements. It's just that I don't see how that thing hanging off the back improves anything, and I don't see how your suggestions for the front improve anything either.

Well, given all the discussion for years on this website, about streamlined tails, coupled with the OP's reported mileage improvements, what sort of other aero improvements did you have in mind?

After all, that thing hanging off the back is similar to various tractor trailer improvements, such as inflated bags, fairings, etc.. Rounding the front will surely help, too, as with horse trailer vertical semi-cylinder, or per blister mods common to many tractor trailer rigs, etc..

Drafting is commonly known to improve aero efficiency of front and following vehicles, such that if done right, two are better than one, and even the front vehicle benefits vs. no draft vehicle.

So, what aero improvements do you suggest?

[Frank Lee]

The same things that have always been suggested and proven to work.

Cap on the tow vehicle if it's a pickup. The closer it matches the trailer height the better.

Boattail that isn't angled too steep to be effective.

Minimized gap between tower and trailer.

Radiussed leading edges on trailer, keeping in mind that more radius than necessary has the effect of enlarging the gap tween tower and trailer, and taking interior volume away. I forget the formula for calcing radius size but it's here somewhere.

That tail just has the appearance of being so trunciated that it would mostly exist well within the turbulent zone, thus affecting flow how? Perhaps there is some benefit from it's side panels allowing some reduction in trailing wake but really the 3-4 mpg claim mystifies me.