Tow behind tailcone

[Varn]

I have an acquaintance that built a trailer to tow behind his van. He used it haul his streamliner bicycle to races. He claimed that it improved his mileage by filling in the negative pressure space behind the van.

The shape is a simple tear drop shape when viewed from above. The top is flat. I only have one photo of it that doesn't really show it well.



Here is a recent communication from him:

We used the Harbor Freight trailer kit to start from. Got the largest diameter tires and wheels they offered. Pretty much threw the frame part away and kept the axle and hitch.

I used 2" X .065 square tube for the main frame, 2" X .125 for the center spine to the hitch, 1" X .065 for the verticals on 2 foot spacing and 1/2" X .065 on one foot spacing for the rafters. we nailed wood forms to our back deck to form the aero shape of the 1" tube.

The skins are aluminum .065 thick 5' X 12' sheets. The height of the trailer is 5'. I put the aluminum skin on with 1/8" stainless pop rivets for most of the structure with 3/16" along the lower front. The top skins are .032" mostly because I had them from a previous project

It was made to fit behind a full sized Ford van which helped the mileage quite a bit.

It is taller then the mini van so does not do much mileage help on it
maybe if the corners were cleaned up a bit ....

....
The photo that I have is here: The side door is open and it pretty well hides the trailer.

[aerohead]

I like to think there will be a future for these.
I crashed mine in December and had to abort the trip,but for the limited mileage I was able to record,at a 1,000-lb penalty I was still getting 4-mpg better than stock,without the trailer.
With the trailer gap closed off there is upwards of an additional 10% mpg available.

[Piwoslaw]

I would think that for towing low, streamlined bicycles the trailer does not have to be 5ft. tall. Making it 3-3.5' at the front and 2' at the rear would see a much bigger improvement.

[KamperBob]

Varn, thanks for sharing. If you can rustle up more pix eventually that would be great.

Aerohead, agreed. I have actually EXCEEDED my Tundra's EPA rating while towing my 3500# fifth wheel camper!

Piwoslaw, remember that trailer was designed for a full van: it probably height matched for continuity. Being able to move around inside the trailer (if hunched) might be worth gold to the owner. The assertion about relative benefit of tapering down the pointy part is arguable. More data is needed.

Cheers
KB

[Varn]

The trailer was tapered to a vertical line as he wanted the length for his bicycle.

That is interesting so I am hearing 3 data points all positive. I don't like the idea of a long tapered extension on the back of my Econoline.

Originally Posted by KamperBob

Varn, thanks for sharing. If you can rustle up more pix eventually that would be great.

Aerohead, agreed. I have actually EXCEEDED my Tundra's EPA rating while towing my 3500# fifth wheel camper!

Piwoslaw, remember that trailer was designed for a full van: it probably height matched for continuity. Being able to move around inside the trailer (if hunched) might be worth gold to the owner. The assertion about relative benefit of tapering down the pointy part is arguable. More data is needed.

Cheers
KB

[Piwoslaw]

Originally Posted by KamperBob

Piwoslaw, remember that trailer was designed for a full van: it probably height matched for continuity. Being able to move around inside the trailer (if hunched) might be worth gold to the owner. The assertion about relative benefit of tapering down the pointy part is arguable. More data is needed.

Granted, being able to climb inside is valuable. What had in mind was a design where the whole top came off, so the internal volume was only the bare minimum. Would also help rear visability.

[Varn]

Piwoslaw:
Are you going to build a tail cone trailer with a removable lid?
Probably with a small car that might work good.

Originally Posted by Piwoslaw

Granted, being able to climb inside is valuable. What had in mind was a design where the whole top came off, so the internal volume was only the bare minimum. Would also help rear visability.

[Piwoslaw]

Originally Posted by Varn

Piwoslaw:
Are you going to build a tail cone trailer with a removable lid?
Probably with a small car that might work good.

Not at the moment, as I don't even have a trailer hitch. But if I will ever need to haul more than I can fit inside, then I'm sure I'll start an aerotrailer project. Maybe if/when we start building a house?

EDIT: I just realised that with an aerotrailer, not only would my drag be reduced, but I'd also have a pretext to drive slower. In fact, I'd have to drive slower, since the speed limit here for cars w/ trailers is 70-80 km/h, compared to 90-130 km/h for normal cars. So less tailgating and light flashing



I wish the lower speed limit also applied to cars with roof racks...

[euromodder]

Honda had an experimental trailer for their Insight 1 that continued the ideal aero shape further, leading to reduced aero drag.
They used flush but flexible panels to bridge the gap between towing vehicle and trailer.

[silverinsight2]

Originally Posted by euromodder

Honda had an experimental trailer for their Insight 1 that continued the ideal aero shape further, leading to reduced aero drag.
They used flush but flexible panels to bridge the gap between towing vehicle and trailer.

Any pictures or links please?