What should US Travel Trailer makers do?
 

I've got a challenge for the more creative people on this site...

We bought a travel trailer last year and learned quite a bit in the process of shopping for one. Like the cars on a train they are boxes on wheels to maximize interior space and utility - round the corners and it screws up something or other on the inside and pushes cabinet costs skyward. And at $15,000 on up, people won't pay for much in the way of fancy aerodynamics.

Also, it's a fairly major industry in some US states. (It's actually rather surprising that anything is still made in the US and not imported from overseas.) I imagine it's dying a horrible death right now - along with a lot of real jobs where they create real things.

Anyway, I thought I'd challenge the people on this site to come up with suggestions on what the trailer designers could do, cheaply, to improve the aerodynamics of their products and save their industry.

Just Google "images" for travel trailers and you'll see few design concessions are made by the manufacturers towards aerodynamics. (The 5th wheels are little better.)

eg - this is like the one we bought... a K-Z SPREE and I sure hope that big indentation in the front centre is a fancy aerodynamic trick - to me it sure looks like a parachute. http://forum.ecomodder.com/images/smilies/eek.gif

http://i1.imagesrv.com/1/564/i/50118...83_1037856.jpg

The front end on that trailer is designed for adequate strength with a minimum of material, plus a window option. The recessed clearance lights are the only feature that might have been done for airflow.

Perhaps the best thing we could do for the trailer industry would be to make a kit of parts that would create a fairing to the tow vehicle. That would be better than having everyone make Airstreams. I'd start off by trying a big Coroplast box over the trailer hitch, flush with the sides, designed to support the back edge of a big cone attached near to the maximum diameter of the tow vehicle. The cone would only need a bit of bungee cord to keep it in shape, since air pressure would help hold it in position at speed. If wear ever becomes a problem, an extra skin could be stuck on.

Welcome to Award Recreational Vehicles

Ive heard that these are some of the most aerodynamic travel trailers. I saw one for sale nearby a few years ago. It also had the frame beams drilled to reduce weight.

Not knowing if they have the same length, weight restrictions as tractor trailers etc ... and advancement in that industry would be to adopt a system like the cruise liners. Build the interior component first then build the outside around it. That way you can still have a basic rectangle shape as a lead in price point then offer, aero add ons, like a front nose, teardrop roof line, boat tail rear, wheel skirts.

Offering these items as gas saving upgrades with data to back up fuel savings over the life of the trailer.

The idea has been thought of before.

Bowlus Road Chief

Airstream, Inc :: Flying Cloud

Most travel trailers only travel about 500 miles a year. Unless you are one of those exceptions that travels more. the aero advantage is not worth the scarifice of cost and interior space.

Beat me to it :p Not sure what the average is but the 1 percentile that puts many many more miles on isn't convincing enough to spend the money on R&D, implementation, etc.

All of that aside. I've been collecting a set of "Aero Rules" - here's a few that apply... I haven't really edited these - so pardon any goofy language :p Names in the curly brackets are the source/author ;)

Front Corners shall not have a radius to vehicle width ratio (r/W) no less than .045 {PAWLOWSKI}

Winshield angle from vertical shall be biased towards 90 degrees to reduce cD {G.W. CARR} but, the reduction is not as much as assumed. After beyond 60 degrees, there is almost no further reduction and may result in optical refraction and cabin heat issues {R. BUCHHEM, et. al.}

Lower Stagnation Point is better {R. BUCHHEM, et. al.}

Optimal roof camber ratio (a_r/l_r): .065 Where a_r is height above "flat" roofline and l_r is the length of "flat" roofline. Assumes FA remains constant. delta cD = -0.02 {R. BUCHHEM, et. al.}

Optimal taper angle is highly dependent on the "history" of flow. {HUCHO}

With increasing length, positive effect of tapering become weaker. "Bob-tailing" or truncating thet taper results in little loss in drag reduction {D.J. MAULL, W. KAMM}

Rear diffusers: For a given area ratio (outlet area/inlet area), long diffusers are better. The same drag reduction can be had with a smaller angle rather than a shorter diffuser). Small angle = 2 degrees {J. POTTHOFF}



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What does all that mean?
1. You don't need much corner rounding to make a significant impact
2. Both top and side profiles should bell outward in the center (camber)
3. For long objects - resisting resistance is futile...


I think it'd be cool to see these things made like large fiberglass boats. Prefab the "hull" - drop in the prefabbed innards... Glue on a "deck." That as opposed to the prefab wall on chassis method. If precise enough (and composite tooling can), a non square cabinet can be made a "standard" (routed wood or blanked/compressed composite) and allow for fast assembly that fits well.

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Now what should they do - aero aside?

Optimize material selection, manufacturing process and feature selection. Put cost, quality and innovative features as top priorities. Other factors should be secondary or tertiary considerations only if one of the three will benefit.

We're still looking to buy a fullsize trailer next spring, but not 100% still. Size and weight is a concern of course.

I've yet to drag my tent trailer project into the garage for work yet. We're looking forward to trying this out next spring whether we get a fullsize or not. The tent trailer is small and light enough to be pulled by my Grand Cherokee. And our F150 hardly notices it. I know a couple folks that traded from fullsize trailers down to tent trailers that also carry ATVs. Size, weight, wind resistance had as much to do with their decisions as pulling only one trailer (Utah allows double tows without CDL) to save fuel.

What?
 

The members have pretty much covered the physics of what could be done.Perhaps the manufacturing companies could present some "concept" trailers at their traveling RV shows around the country and see if they get laughed off the premises,or if people queue up to place orders. "Virtual" tours in autocad would allow the potential" market" to view and experience "virtual" trailers at relatively little cost (compared to experimental full-scale prototypes). Either way,if there is no public interest,"good business-practice" will dictate that they do nothing until forced.---------------- Preston Tucker established a business practice like the mobile home industry,marketing a product which did not yet exist.Color graphics by Alex Tremulis were enough to launch a car company based expressly on consumer expectations.Perhaps it is a propitious time for the RV industry.------------------- With accounts-receivable,in the way of deposits,venture capitalists will usually "smell" money and release startup money for a product launch.You just have to steer clear of Michigan State Senators!

I think Airstream is the best going right now.

I had a 34 foot HitchHicker 5th wheel with a wing attached to the top of my pickup. It help with the wind, but was a trial and error on the wing angle. I think a lot has to do with the tow vehicle and how it channels air around the trailer - then up to the trailer to exit the air smoothly. You see some big rigs set up for something like this - let me find a pic somewhere...

Here is an example to get things brainstorming...maybe RV manufacturers could offer aero kits for the tow rigs to match the RV aerodynamics?

http://bioage.typepad.com/photos/unc...7/trailer2.jpg

Lonestar:

http://www.gizmag.com/pictures/8785_8020860512.jpg

Aero RV stuff:

http://lh6.ggpht.com/_9C8JdUyXU6o/SA...2_051902AA.JPG

Titanium:

http://www.glendalerv.com/2006/Titan...9RKPofile1.JPG

Maybe a modified "hi-lo" would be a good base to start out with then improve from there?

http://cdn.psndealer.com/dealersite/...%20in%20az.jpg

PS I sold my HitchHiker and now just plan on throwing my tent in the Metro - how aero is that?

this may have been posted before.
its one of my professors

Ken Visser Research Page

I wonder if this could be placed on a van or SUV and get similar results.
Ray mac.

I’ve thought about this – strictly for the 1-percentile that puts 25,000 miles a year on an RV (race crews, etc).

Using my truck as the tractor. Mine is lower than usual and only SRW, so the cab shows 79.9” wide and 72” above grade. At the top of the bed (48” above grade) it tapers in on a 34 degree angle to be only 48” wide at the top of the cab.

The Bowlus Road Chief was 80” wide (todays RVs are at least 96” wide).

Start with a 79” wide Hi-Lo design. (Using my truck’s dimensions) have its road operating height no more than 71”. In camp it deploys higher. Compensate for loss of space (by making it narrow) with some additional length. Taper it in at truck-cab angle at the top. Now nothing “shows” in the air stream – just a small step at the interface.

Given the cites posted by trebuchet, I wouldn’t go wild on the shape – just avoid the A/C tumor on top and round the edges a la Airstream.

Check out patent # 6959958 by Tourigjm's Professor Visser. He combines the use to vector generators and enclosed and open panels mounted to the rear doors of the trailer to obtain a significant reduction in drag. When multiple panels are used, they appear to taper inward at a 20degree angle from the rear of the trailer. The "dirtier" the front of the tractor/trailer combo, the bigger the reduction in drag. You should be able to find it Patent Storm.com. You will have to register but the process is fast and free.

Perhaps this is a naive (or dumb) idea, but how come nobody just puts an inflatable boat tail on the back of trailers?

Make it out of the same material used in those bouncy houses that kids like to play in. No worries about hitting stuff (it'll bend/deform), and just collapse it when not on the road or when there are clearance issues...

*scratches head* how come nobody does this? Seems like it would be pretty inexpensive and it wouldn't compromise interior space or construction techniques...?

Chaster

Its not dumb. I have seen pictures of similar devices made out of rubber or plastic materials. The drawbacks are remembering to deflate them or open the doors to which they are attached before getting to close to a loading docks and other objects. Also they cost some $ and only last about 5 years.

Another problem is that independent truckers ( who pay the fuel bills on the runs they make) often don't own the tractors they haul. One solution is government requirements or incentives to tractor manufacturers.

Hm, okay, so how about the following ideas to address these challenges:

1) I realize they would cost money to make, but it seems that if they were mass manufactured (like inflatable rafts, beds, etc.) are then they could be made for a relatively low cost (say, less than $300). If they save 10% on fuel bills, the trucker would make that back in probably just a couple long hauls.

2) I know that the truckers often don't own the tractors, but seeing as how these are essentially add-ons that the trucker would attach to the back of the trailer during a long haul (using some sort of clips), and trailers are fairly standard in dimensions (:confused:), it seems that the truckers could add these on to their loads themselves.. I don't see why the manufacturers have to be the supplier?... Or maybe my ignorance is showing through.. heh..

I agree. There is no doubt that alot of $ and fuel could be saved on long hauls. As fuel prices significantly increase, as I suspect they will, there will be more motivation to make changes. A fair number of independent truckers have made improvements to their tractors and some fleet owners have made changes to their tractor/trailor combs, but it might be tricky to come up with a way to attach a device to some one elses trailor without putting mounting holes in it that might cause leaks when the device is removed.

Now if the aerodynamic aftermarket industry and the trucking industry or the government could come with standard mounting plates to be attached to the rear of existing and new tractors, I think that significant progress could be made.

If they do not, they will face incresing competition from the railroad industry that can deliver more cargo at less cost as fuel prices rise. Warren Buffet, one of the most successful investors of our era is betting on the railroad industry.

Most travel trailers only travel about 500 miles a year. Unless you are one of those exceptions that travels more. The aero advantage is not worth the sacrifice of cost and interior space.

Travel trailers vary greatly in design and application. Most are sold, these days, to those with time (older, no children at home). Since the de-regulation of airlines in 1978, the tremendous increase in commercial truck traffic at the same time, and the decline in the average Americans income (since 1972; against increased fixed costs), the day of all-aluminum, aerodynamic trailers has pretty well passed. Cheaper, easier to fly & rent for many. But such was once not the case, as the better trailers were bought by families for extensive travel. This is to say that the high end travel trailers were meant to be used for decades, with excellent road manners, and low overall cost of ownership.

I'm third generation, looking for yet another. My folks kept theirs for 27-years. As to the "practicality" of the right travel trailer (TT), aero has significant advantages not only in fuel economy. Rounded edges/corners/fully enclosed undersides means winds just roll off of them. I have seen ordinary "boxes" heeling over like sailboats, and accidents from strong winds are not rare. Same for being parked. More than once I have seen an aero trailer advertised as being a survivor of multiple hurricanes (FL) where others blew away or blew apart.

Most important is in handling the headwinds of tractor-trailers, especially when on a two-lane and several trucks coming the other way are traveling close together . . the effect of multiple bow waves is an accident coming at you (if the trailer is a box). A "sway-eliminating" hitch is only just good enough (such as Pro Pride).

Aero-formed with light, strong construction has no equal. When the trailer also has independent suspension, the combination cannot be beat (assuming also disc brakes) for roadworthiness.

I am aware of no space reduction on trailers from, say, 1960 to 1990 (the ones from the 1930's to the early 50's were towed behind seriously underpowered cars).

A fuel economy gain of 20% is ordinary. When the TV (tow vehicle) is intelligently matched, the gains can be better if one is perfectionistic about all details related to "steady state" highway operation (my term). A turbodiesel is the best in that case. (The Europeans received the Chrysler 300 in wagon form with a near-perfect TD engine that could have been a heckuva TV for North America, at a reasonable price).

The gains are in fuel economy, unit life, and on-road performance. They must be balanced. (And you would never see me buy a square white box as they fall apart after a half-dozen years, have terrible road manners, poor insulation, etc).

The better ones (Arctic Fox) may last a bit longer, but suffer from the shoebox design that never allows one to feel as if he were sitting outside once parked. Unfortunately the AWARD trailers had serious deficiencies. CASITA is one brand of tiny trailers that is well received.

If someone were so inclined, a good project helpful to all would be to design an alternative air-conditioner shroud, as those roof units are used on all types. That the manufacturers have low-profile units now only illustrates the problem.

There are plenty of us (a small subset, granted) who have, or will, travel full time with extended parking contemplated for living. Also, being on the Gulf Coast I see a good trailer as being nothing more than prudent. The number of people in the future needing affordable portable housing will only increase, IMO. Aero is part of that. One should not need a pickup to tow a 7,000-lb trailer.

J. Baldwin, long-time Tech editor for Whole Earth, resided happily for many years in an Airstream. It was known as "the Silver Turd."
I've had tentative plans for a bus or trailer conversion with all the utilities lined up on one side, and the other wall folding down into an extended floor, with an arch-rib greenhouse structure filling the resulting gap.

[QUOTE=slowmover;167985][I][B].

"If someone were so inclined, a good project helpful to all would be to design an alternative air-conditioner shroud, as those roof units are used on all types. That the manufacturers have low-profile units now only illustrates the problem."

An inexpensive alternative that is sometimes used, is to mount a conventional 5000 BTU window air conditioner to the front or back of of the travel trailer. Either location fills part of an aerodynamic low pressure area that otherwise creates drag. Also this arrangement does not add to the frontal area as a roof top unit does. If need be, you could install ducting to carry cool air to the opposite end of the trailer. Often you could also arrange to park the trailer so that the air conditioner is in the shade most of the day which would make it a little more efficient. Of course you would need to hook up to an AC source when parked or use a large capacity DC to AC converter.

If you want an areo camping trailer, try a motorcycle trailer. My friend had one that he pulled behind a Honda Goldwing
Mustang trailers

[QUOTE=4536;168059]Yes, but . . window frames are not built for this load; the A/C must be secured somewhere for travel (damage potential all around), etc. I have seen A/C mounted internally (done very well), but it takes up storage space that is usually at a premium (where weight, shape and road performance take precedence). It is favorable, however, that the roughly 100-lbs of weight is lower on the chassis, but a roof mount directly over the axles helps offset this problem of COG and FF/RR balance.

Todays RV A/C units are, unfortunately, disposable unlike those of yesteryear. Cheaper in all ways with no field serviceable parts. So any shell mods must accommodate ease-of-removal. Even for mobile command units, etc, the tendency is to use roof-mount, for sliding a new one in place takes not much longer than describing the work. Obtaining the services of a factory-trained technician and parts/supplies for something more exotic is not tenable for time-critical operations.

Granted that, somewhere, there is a combined HVAC unit for heat & cooling. Initial expense, size, NVH would all be problems, even on high dollar units (one must, essentially, go to units spec'd for million-dollar buses [NEWELL]). Obtaining the services of a factory-trained technician and parts/supplies for something "exotic" is not tenable for time-critical operations OR ordinary travelers.

There is a "solution" for combining water heating and space heating in the PRECISION TEMP line of models, but, again, ducting, water & gas plumbing, plus electrical must be re-engineered. This would free space for an A/C unit, but overall costs at this point have become quite high once an internal-mount A/C is specified. Ducting a small trailer is fairly straightforward, but for larger (say above 25') expenses mount.

For safety' sake, an engineer should be employed to review such major changes as above. RV's are both houses and cars, with a bit of sailboat thrown in. Plumbing for water (from pressurized external source OR from internally-pressurized tank[s]), propane, two electrical systems (12V and 120V), two and three-way operable appliances, etc, etc. There are any number of governing bodies one may argue take precedence: Shall it be RVIA, USCG or NEC? UL or . . . ?

Remember that in many regions A/C is a necessity for a majority of months. Shade is desired but not always available. Combine the viable lack of A/C options and the the desireability of some aero work becomes clearer (where mpg is chasing small margins all over the place). Simplest solution is where economy and long-life are not affected by safety/space/damage concerns.

Thus the point about a more aero A/C enclosure. It is in line with the OP request, ought to be fairly low cost for DIY, and, hopefully, help to manage airflow a bit. It is applicable to virtually every RV. Other roof vents (plumbing, kitchen oven, refrigerator; ventilation passive or powered) tend to be "low profile", but once one adds a second A/C (on larger RV's), storage "pods", solar panels, multiple telecomm antennas, etc, well, . . a "dirty" roof needs all the help it can get.

.

This iswhat my 1976 Boler looks like. Boler sold the plans and the name changed a few times, the latest being "Scamp". This is not my trailer, just while reading this thread I thought I would jump in so I found one on Google. :)

This thing is a work of art in practical design. Nearly every square inch of the interior was used, now with a few mods of mine, it is ALL used. :) I haven't towed it in a few years as a friend has been living in it, (yes LIVING in it). But I know with my 1965 Skylark with a little V8 you didn't even know it was there.

All the cabinets, bed, bunk, etc. are made of fiberglass and formed to the inside of the body. I have had people ask to go in while I am out camping. And I get the same response everytime "It gets BIGGER when you go inside!" :)

Brian

http://images04.olx.com/ui/2/24/61/35062361_1.jpg

These are the same colors as mine. :) Groovy huh?

http://www.favoriteflies.com/bint2.jpg

http://http://www.favoriteflies.com/nicktrip2.jpg

http://www.favoriteflies.com/smoke.jpg

Here is an "Ultravan" that was made in the sixties, powered by Corvair. It was made by an aircraft company and believe me, it's construction looks like it! We have one in the shop right now.

Brian


http://i200.photobucket.com/albums/a...s/100_0797.jpg

http://i200.photobucket.com/albums/a...s/100_0790.jpg

Another plug for fiberglass
 

Right on. Boler was great ancestor to many brands, most of which vanished but a few remain on market. I posted on the other currently-active trailer thread.
http://ecomodder.com/forum/showthrea...tml#post167980
For a more direct link you can learn more about these wonderful little campers here.
Egg Central

Cheers
KB

Yeah, I was going to sell the thing, my wife didn't want me to. My buddy needed a place to live so there it is still. I am now glad I saved it as I have been going on VERY long roads and haven't camped in years but I look forward to going again. I went on ebay looking to see what they do for and they sell for a heck of lot more than what I paid for it 20 years ago! You know what I sold to buy it, a tear drop! Yep, a real, vintage all aluminum tear drop made by an aircraft mechanic right after WWII and even had components from war birds!

Anyway, here is the floor in the Ultravan, it is made of the holding tanks!

http://i200.photobucket.com/albums/a...s/100_5478.jpg

http://i200.photobucket.com/albums/a...s/100_5477.jpg

It has a FULL belly pan under it.

http://i200.photobucket.com/albums/a...s/100_5476.jpg

This thing is very cool, he just got back from a trip all the way to Delaware from Oregon!

Brian

Here’s a little AutoCad study I did on travel trailers. I’m assuming a guy who drives around with a trailer at least 20,000 miles a year – enough to make this rig worth the effort.

Length is 34 feet from hitch to tail and its 79.9 inches wide (doesn’t need marker lights and come fair to a standard SRW pickup). In “down” position the top is 64 inches above grade (same as my pickup).

I married the “Hi-Lo” concept with an 80 inch wide Bowlus Road Chief and put a 70 inch long tapered tail on it. The tail reduces wake area by 58%. I gave it a “toy hauler” configuration. The same configuration would work OK as a straight cargo trailer or as a travel trailer.

Like the “Hi-Lo” the trailer comes in two parts: a “tub” that carries the payload and a “shell” top which is raised once the trailer is parked. The “shell includes a flip-up tail cone that tapers in at an 11 degree angle in all aspects. The dimensions of the “tub” dictate that I cannot taper the top until the back of the “tub” is cleared. This assumes full “tub” cargo height all the way back.

Instead of having a cancerous tumor on top of the trailer for HVAC, I would build mine into the nose of the trailer, along with propane cylinders and maybe even a generator.

Why is it so long? Answer: To regain space lost by making the trailer low and narrow. The “tub” (payload) volume is 240 inches long by 76 inches width (interior dimension) by 54” high. That comes out to 985,000 cubic inches. Your average “Wheaties Box On Wheels” is 104 inches wide by 80 inches high (interior dimension above load deck). So the load volume of my aero trailer is roughly the same as a 10 foot long standard trailer. At best, Spartan accommodations for two. The triple axle is probably not necessary unless you carry Die-Hard batteries for cargo.

I also did a 108 inch wide by 80 inch high version that makes a fairly good car hauler.

Is it aerodynamically superior to the average box on wheels? Of course. How much? I don’t know. A wind tunnel would be necessary to determine that, but I’d say it had better beat the box on wheels pretty bad to justify parking a 34 foot trailer.

BTW, sorry about the shabby picture of an AutoCad drawing. I an not much of a hand at sharing data files (I’d rather think about cars) and AutoCad (as I know it) wants no part of Ecomodder, so I simply took a picture to help everyone visualize what I’m talking about.


On edit.
Forget the attachment. The durn thing just will not co-operate. If anybody cares, send me a PM and I'll send you a 1.35 Mb picture or a .dwg file if you want it.

Looking at this page, I'd have to say that the makers should try to get the good designers and the good salesmen onto the same teams. The acres of 1X2 and house-siding garbage out there are disheartening.

I bet would this trailer would do very well behind a SUV. 7 feet wide ,total height only 7 1/2 feet , the sides even taper inward behind the wheels and it almost fits the ideal profile

https://www.tc.gc.ca/eng/programs/en...-2939.html#s73 check out what i found

I'm going to just build my own, after looking at costs of a new one and then costs of the materials they use it looks like they are loaded with profit. Much more so then the average car which I assume is because the volume is so much lower. Anyway, nobody builds a true areo camper. I saw somebody post the average camper only travels 500 miles per year and I believe it but the question is why? I'm sure the owners plan on more when they buy them but then the reality of 8mpg and $4/gal hits and they just can't afford the 500 mile trip each way to the beach, national park, or whatever. At that point the $500 spent on gas would buy hotels. My thing is also the wear on the tow rig While your drivetrain is getting 8 mpg it is also working it's butt off.
For my design I think I have settled on a design that looks like a boat from the top and a tapered box from the side. That gives me mostly upright but curved side walls and flat but sloping roof. About 15' long not counting hitch by 6.5 feet wide. I will keep the hitch short about 2' and the trailer about 1' off the ground with a 6.5' max interior height.

The other reason Airstreams are good: they last. Most trailers don't.

They last, but they don't $80,000 last, that is ridiculous.
They aren't all that aerodynamic either, they could do a lot better.

I may add a campershell then add a frame and sheet extension like my other topper...or modify or build another topper

Aero trailer:

http://ecomodder.com/forum/attachmen...8&d=1405359064

With the boattail installed, it's no higher than the minivan pulling it. It's a box, but it's a smaller box than the TV.

Campers are one of those places where you can't have your cake and eat it, too- usable interior space and effective aero work against each other. The practical limitations (amateur drivers and people who strap gear all over the place) are worse for campers than big rigs. I just don't see any improvement for production models.

BTW, the US RV industry is doing just fine. Elkhart County, Indiana is still a stronghold.

RVs are tough to offshore because of the transportation costs.

One of my clients makes them and he builds regional factories to keep transportation costs down.

Has your client looked at Local Motors and their microfactories?

The cost has laways been high, relatively, A fixed location vacation home, or an all-aluminum, aero TT with independent suspension. Both are financed the same way with second mortgages. But the AS can go wherever you want it to go. True now or in 1965. Cheap if you actually understand whta you are getting for that money which is decades of service, not a half dozen years. So buy a used one. Ten years old is still a new AS.

The shape and layout has been been pretty well standardized since the mid-1960's. As to how areo they are I'd suggest you aren't thinking of how they're used. And that is stationary. Interior space layout is central.

They're on-road performance speaks for itself. Nothing else comes close . . and in this we speak of braking and handling. As to MPG, a turbodiesel tow vehicle will be the champ. Breaking into the 20's is not a challenge.

.

I am working on my 2011 Apex trailer aerodynamic mods now. As a trailer owner I am here go tell you poor aerodynamic performance is a concern of mine. Base mpg in good conditions can be between 11 to 12 mpg. This limits traveling simply because of the fuel cost. Having the same trailer that could get 14 tp 15 mpg would be a real coup. I have built appliances to help push the air from the tow truck (F 150) up over the trailer but this is not enough. I am looking at front facia for the trailer to store air from hiting the front edges and to act as a gap filler. I am also looking at a 3 ft boat tail to reduce the wake area. See my aero mods for trailer towing post.