Boat tail mod to my enclosed trailer

[slowmover]

Originally Posted by Frank Lee

21 to 15 towing sounds about right. My F150 goes from 18-19 to 13 or so pulling a big heavy flatbed. It does take more fuel to do more work.

30% loss is common, and 40% is normal. Figure 30% on a very good enclosed trailer, and 40% on a trailer that is a square white box as a rule of thumb.

These percentages were as true in 1970 as they are in 2010. Just page through some circa 1970 Trailer Life or Popular Mechanix articles and some reviews from today (or poll members at RV.net). I well remember these numbers, and from family members back into the 1950's.

The jump to 12 mpg was sweet. Hope to see more of that. I still believe you'll do better with a speed of 58-60 versus 64-66 mph. A ScanGauge is a good idea, but so is an airspeed indicator.

FALCON AIRSPEED INDICATOR<BR>0-80 MPH from Aircraft Spruce

A full or 3/4 crosswind is murder for towing numbers. Winds generally rise, then peak, during the day, so plan stops and a long lunch accordingly. (There are folks who drive at night to negate winds, but the safety trade-off is terrible, so, only in an I'm-dead-broke emergency).

Alternate routing is also a consideration. The longer the trip, the more the possiblities. Off the top of my head I can think of three approaches en route from Austin to Seattle. 3/4 winds trump head-on as to what's worst, as to FE. If you can predict mpg drop per time or distance based on records, then you will know how far OOR you can go (out-of-route) to offset the penalty before distance catches up with you. I'd happily pay the penalty -- while on the job -- as this is the entire point of FE in my mind: be able to make changes that allow for the least set of problems on the road. Avoiding I-90 thru Chicago is one . . avoiding a day of fighting winds is another.


DON'T! cruise control monitors vehicle speed many times a second and adjusts it accordingliny by adding more fuel or less as needed or even decellerating via brakes, which can be a big deal in a heavy setup like yours.

Might be fine for a solo vehicle. But is lousy with a tow vehicle. You did notice that his rig is 14k? You've driven such over very long days to achieve a delivery date? And are working against the driver fatigue to do so?

Cruise control use is proven in the big truck industry. The gain is substantial, repeatable and conclusive. The effort needed -- mentally and physically -- is in no way offset by problems to the driver: reduced attention to the roadway, reduced alertness earlier in the day, etc. If the truck is in a sweet spot according to gearing and engine rpm, then a slightly reduced speed with CC on is the best solution.

The benefit of its use to the driver outweighs the truly tiny gains to be found by manual throttle control. Obviously, the hills of West Virginia may not be the place to use, nor is it to be used in the rain, at night, in the left lane, etc. Dawn-to-dusk, on flat or rolling terrain is what it is designed for.

Again, on a long day, with a heavily-loaded vehicle, the "loss" to CC is so small as to be beside the point. And it is much easier to repeat performances day-after-day by it's use.

Truck driving is about predictable results performed safely. CC is a safety item used properly.

Also, as his truck is fully within spec (but WDH setup I'm waiting to hear about still) the manufacturer tested it with this in mind. It is central to the "mission" of an American pickup truck, thus programmed accordingly.

BRAEBYRN, you might consider an cushion from OERGON AERO that I have heard many praise (not at all what you'd find at Wally World or the truckstop, has science behind it):

http://www.oregonaero.com/softseat

I also did some reading about posture over the years as it relates to controls and safety in driving, so here's a post on that from another site:

http://www.cumminsforum.com/forum/2409680-post56.html

I sure admire the work you're doing, and look forward to more.

.

[aerohead]

If you choose to do a air speed indicator,Dwyer makes a nice slewing pitot-tube which will 'follow' the apparent wind.
I believe that a fixed pitot-tube is only good for up to 12-degrees of yaw,and at low speed in a strong crosswind the Dwyer unit would compensate 100%.
When placed within view they also make a great tattle-tale for your wind environment.

[Braebyrn]

Slowmover, I will check out that seat cushion and put it on my wish list.

I don't know if I will put on an airspeed indicator. I already get enough comments with the boat tail. But hey, it might happen. I just like seeing the savings at the pump.

On the weight distributing hitch, I most likely will stick with the one that I have been using. I wish I could afford the nice ones, but that isn't the case.



Varn,
The zote foam I will have to check out. You say its flexiable? It may work good where I don't need it to flex as much, but maybe to take up space too.

Aerohead,

What does yours look like? I wish I had some education in engineering. Seems like it would help with the design and construction.

Bamzippow,

I did that with the nose cone, good idea and it works great.

[aerohead]

Braebyrn,I don't yet have photos fit enough to post so I'll attempt to describe.
* very close to the tongue is a vertical receiver tube of 1-1/2'' square steel tubing with 3/4" lock-bolts.
* into the tube slides a section of 1-1/4" square tubing which 'pinches' the handlebar bracket of bicycle fork tube/fork assembly,which nests into a axle receiver at the base of the 1-1/4" tube.
* the fork assembly maintains the weather-tight ball-bearing sets and performs as the lolly shaft of a windmill,allowing slewing.
* onto the fork assembly mounts a welded steel C-Frame with triangulated bracing.The open part of the C faces down and straddles the trailers pull-bar.The C-frame pivots.
* onto the C-frame mount the 4 gap-filler panel frames with their body skins which are hinged like the canopy of a Lancair,with deep 'Cs' which allow flush fit of the panels plus 90-degrees freedom of movement.
* the upper panel frame rides a pivoting castor near upper center of the trailer face.
* the side frames contact the trailer face/sides with rollers( from inline skates
* the lower panel also rides on a pivoting castor
* all the panels are held 'closed' by cable/pulley/weights.( I considered using springs but they can break )
* an 'integration' panel replaces the tailgate,fills the gap to the C-frame,and has rollers which contact the C-frame face
* as the truck pivots the C-frame is forced to pivot which forces the affected panel frame against the trailer face,swinging 'away' to allow the turn articulation until the rig straightens at which time the weights/cables and pulleys pull the panel back 'in' to the stowed position.
* on my T-100 there is an additional boat-tail upper panel which completes the aeroshell which hinges from the aeroshell to allow upper 'compressions' to be relieved when negotiating driveways 'n such,spanning the upper void to the C-frame.
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It's a lot more simple than it sounds.I'll do color-coded photos as the project unfolds.

[Braebyrn]

Cool, this is going to be interesting to see! There are so many different ways to skin a cat, so to speak. My dad always said that, but until I typed it out, it doesn't sound that good.