Full-boat-tail trailer with gap-fillers for Toyota T-100 pickup

[Bmak]

This looks amazing !!! great Job

[aerohead]

Originally Posted by euromodder

In this situation, you don't really lose fuel energy or efficiency to braking.
There simply wasn't anything to be gained when you can come down the mountain using engine braking or aerodynamic braking with the engine off.

But you still had to drag the trailer up the mountain first.


There's a limit to that as well - the uphill part would have drained them to as low as the conditioning software will let it, but once the batteries are full, the harvest is over.

And these batteries too, have to be dragged up the mountain first.

I believe that these engineers look at thermodynamics and BSFC when they do their numbers.If any kinetic energy of a downhill descent is lost to braking,then they enter it as a loss in the energy balance.
The Chrysler engineer who published the paper on the Chrysler De Soto Airflow streamlining based all work on thermodynamics.
The context of what I posted was kinda like this:
*You take a SMART EV with a gasoline equivalency of 40 mpg @ Cd 0.38,then put the 620-lb Battery-Range-Extender Trailer behind it,which drops the drag to Cd 0.15.
*The aerodynamics boosts the efficiency to 52 mpg.
*Allowing for the added rolling-resistance of the BRE trailer,the mpg drops back to 48 mpg,an 8-mpg improvement over 'stock.'
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*On mountain highways,up to 2% gradients,the uphill and downhill basically cancel out according to AASHTO.I'm not in a position to dispute their peer-reviewed science.
*On mountain highway grades in excess of 2%,the EV,with regenerative braking,can provide runaway control via regenerative braking, which I understand will recover 80% of the kinetic energy,partially recharging the batteries on descents.(Mr. Sharkey wrote of such things when he traveled long-distance with his range-extenders).
*The 8-mpg advantage helps offset the climbing penalty of the trailer.
*The regenerative-braking helps recover 80% of the energy lost on the climb.
*And we never had to 'brake.'
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Without the regenerative-braking,the trailer forces me to use my brakes,causing an mpg penalty.
*If the trailer were 200-lbs instead of 620-lbs I think I could shrug it off.That will require a complete redo.And I believe it would be worth it.
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*When USAC tested their CRXs back in 1984,between Clinton,Oklahoma,and Santa Rosa,New Mexico,They lost 24% mpg on the uphill run,and gained only 14% the same stretch downhill.
*When Popular Mechanics tested their Geo Metro LSi from San Francisco,to New York,they saw a 6% drop climbing and only a 5.6% gain going downhill.
*Motor Trend realized similar phenomena with their CRX between Los Angeles and Salt Lake City and back.
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I'm pretty confident that the trailer's extra weight is beating me up in the mountains.
So it's go on a diet, stick to the flat lands,or pay!

[slowmover]

There was no way to have trans-continental trucks without the long, easy grades of the Interstate system. It wasn't just the difficulty by (what were still mainly gasoline-engined trucks) traversing tortuous grades and truly difficult descents and fuel consumption, it was that the vehicle drivetrain wore out prematurely.

The story of the engineers and surveyors laying out railways in the 19th century is full of this detail. One bad choice by one railway company compared to a competitor crossing a similar yet distant "difficulty" could be the margin that broke them.

Pre-Interstate highways nearly always followed -- as possible -- rail lines for just this reason. They, in turn, often followed water courses for the same reasons, yet again.

Straight lines on a political map are deceptive. One needs to keep close at hand a geographical atlas. The historical names have resonance, too, when out West. The lines travelled are usually as old as human presence in the New World.

.

[aerohead]

Originally Posted by slowmover

There was no way to have trans-continental trucks without the long, easy grades of the Interstate system. It wasn't just the difficulty by (what were still mainly gasoline-engined trucks) traversing tortuous grades and truly difficult descents and fuel consumption, it was that the vehicle drivetrain wore out prematurely.

The story of the engineers and surveyors laying out railways in the 19th century is full of this detail. One bad choice by one railway company compared to a competitor crossing a similar yet distant "difficulty" could be the margin that broke them.

Pre-Interstate highways nearly always followed -- as possible -- rail lines for just this reason. They, in turn, often followed water courses for the same reasons, yet again.

Straight lines on a political map are deceptive. One needs to keep close at hand a geographical atlas. The historical names have resonance, too, when out West. The lines travelled are usually as old as human presence in the New World.

.

A now- retired local mechanic told of a time during WW-II,when trucks would come through Denton,Texas hauling bomber components from Willow Run,Michigan to Ft.Worth,Texas for final assembly.
The FORD flat-bed truck engines had to be overhauled before the return trip back north.
In some areas of the country you can still spy decaying remnants of the old,2-lane highways along the way and sense the bygone days on those 'tortuous' paths and precipitous drop-offs.
The Interstate highways ARE really sweet by comparison.

[aerohead]

Originally Posted by Cd

Phil I know the Texas Mile is not long enough of a track to attain full speed, but wouldn't it be useful somehow ?
It's less than two hundred miles from your house.

It dawned on me that at Goliad,Texas (Texas Mile),at about 115 feet above sea level,that on a mild day,a vehicle WOULD develop full horsepower.
The air drag would go back up to 'normal',but during the acceleration,there'd be a power advantage early before the air drag started to catch up.And you'd be on 'pavement',not damp SALT,which appeared to cost everyone at Bonneville.
With proper gearing,a vehicle might have a shot at top speed.
It would be an interesting comparison.

[euromodder]

Originally Posted by aerohead

*On mountain highway grades in excess of 2%,the EV,with regenerative braking,can provide runaway control via regenerative braking, which I understand will recover 80% of the kinetic energy,partially recharging the batteries on descents.

Sure, but when the battery is full, you're done regenerating, done gaining back the (extra) energy you pumped in going uphill.

Regen might regain 80% of the kinetic energy, that's not a lot compared to the potential energy it can get stored in it due to the increased height.

Without the regenerative-braking,the trailer forces me to use my brakes,causing an mpg penalty.

But that penalty is entirely caused uphill.

If without the trailer you're not using fuel going downhill, and your speed is kept in check by the aerodynamic and/or engine drag, then there's simply nothing to gain by adding the trailer - regardless of its weight.

You simply can't improve upon infinite mpg - unless you add regen

Lightweight regeneration, that is, or you'll need to work off another weight penalty.

The trailer penalty will be less as it gets lighter, but without regen and short of a "design-downhill" matched to suit your streamlined combo, I'm rather confident the penalty will always be there in the mountains.

It'll get less as you shed weight, but it'll never go away completely.
So you might reconsider the time and expense you want to spend on it.

I'm pretty confident that the trailer's extra weight is beating me up in the mountains.
So it's go on a diet, stick to the flat lands,or pay!

Or get a vehicle with regen, and streamline that ...

[aerohead]

Originally Posted by euromodder

Sure, but when the battery is full, you're done regenerating, done gaining back the (extra) energy you pumped in going uphill.

Regen might regain 80% of the kinetic energy, that's not a lot compared to the potential energy it can get stored in it due to the increased height.



But that penalty is entirely caused uphill.

If without the trailer you're not using fuel going downhill, and your speed is kept in check by the aerodynamic and/or engine drag, then there's simply nothing to gain by adding the trailer - regardless of its weight.

You simply can't improve upon infinite mpg - unless you add regen

Lightweight regeneration, that is, or you'll need to work off another weight penalty.

The trailer penalty will be less as it gets lighter, but without regen and short of a "design-downhill" matched to suit your streamlined combo, I'm rather confident the penalty will always be there in the mountains.

It'll get less as you shed weight, but it'll never go away completely.
So you might reconsider the time and expense you want to spend on it.



Or get a vehicle with regen, and streamline that ...

*It is the PhDs at the national research lab which published the downhill penalty,which existed anytime braking was involved.
*The point I'm attempting to illustrate is that when in mountain driving during road tests,the mpg is affected by not only the additional mass going uphill,but also on the descent if it causes braking which does not exist without the trailer,with kinetic energy lost to heat.
*It makes it very difficult for accounting purposes.
*A good reason why SAE says to stick to level roads when testing (not an option for me).
*AC Propulsion's 'Long Ranger' range-extender trailer weighs only about 180-pounds without its engine/generator vs 620-lbs for Viking.
*Viking is longer than necessary for a boat tail.
*A shorter proper tailed trailer with resin-coated papier mache or pre-preg carbon fiber full body would be of insignificant weight liability.
*Long Ranger has radials as well and AC Propulsion reported a 2% mpg benefit which Viking doesn't enjoy.
*If Viking weren't so long she'd fit inside the A2 Wind Tunnel and I could just have the drag measured directly.
*The T-100 debaucle has pretty much scotched any plans for A2 come fall,Bonneville as well.
*Perhaps by spring of 2014 I could be in a position to mock up a modular 'proper' tail/trailer configuration with faux wheel(s) and get it to A2 for a series of measurements of tails and trailer both.

[BamZipPow]

Aerohead...what is the length of yer trailer from the back end of the truck to the end of the trailer?

Been doing some research on single wheel trailers (there's a few of them) and found that this sort of setup might work fer you. It might make fer a longer swing out but it might be something you may want to consider. Would it be possible to adapt this tech to yer trailer?

Swivelwheel 78...
SWIVELWHEEL-78

Swivelwheel 78 attached to a pickup truck.


Swivelwheel ECO...
SWIVELWHEEL-ECO

This company is based out of Houston (Katy), TX.

[euromodder]

Originally Posted by BamZipPow

Been doing some research on single wheel trailers (there's a few of them) and found that this sort of setup might work fer you. It might make fer a longer swing out but it might be something you may want to consider. Would it be possible to adapt this tech to yer trailer?

Swivelwheel 78...

The extra swing out would be limited - and certainly a lot less than a regular trailer - as the swivelwheel trailer can be made quite narrow at the end .

[deejaaa]

i just drove through Katy yesterday. will have to check them out.