Lightweight futility?

General Discussion about almost anything Teardrop or camping related

Postby Cliffmeister2000 » Wed Dec 02, 2009 11:38 pm

07rascal wrote:
Cliffmeister2000 wrote:
hiker chick wrote:
Travelmate - 360 pounds
http://www.golittleguy.com/teardrops/mo ... ifications

Rascal - 490 pounds

http://www.golittleguy.com/teardrops/models/rascal/

Overview

Need something larger than a cargo carrier--something that you can sleep in--but still light enough to be pulled with your motorcycle or small car? The Little Guy Rascal model is built with a tubular steel frame and light-weight composite materials, so that it is light enough to be pulled by a large motorcycle or tryke, and still has all the standard features of a classic Retro Little Guy Teardrop Camper Trailer.



:)


Obviously, I'm a bit taller than average, but 68" interior length would only sleep a 5'6" individual with any level of comfort. I need (and have) 78" in my 1,150lb behemoth! :D


I am 6'-4" and have plenty of foot room sleeping in our Rascal. The pillows rest on the lower curve on the front so essentially you can take the height from the shoulders up and not consider it in the flat length of the floor. In addition the head room is enough for me to sit up and watch TV or DVD in the evenings. Loaded we are 550lbs and towing with our Ford Focus 2.0L Auto we get 28-30. Life is good! :thumbsup:


I hadn't considered sleeping up the ramp! Of course, I have slept on a couch before. If one is tired enough, any shelter one can squeeze into becomes adequate, and most anything is better than sleeping on the ground!
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Postby dwgriff1 » Sat Dec 05, 2009 12:47 am

As is often the case this thread got way off topic.

I'll restate: Would the tow vehicle get better mileage pulling a 300 pound trailer than a 6 or 800 pound one?

I am sure it would get better mileage, but would the margin be enough to justify the search for the lighter weight solution?

Would it make a lot of difference if the trailer were very flat, like a folding trailer might be?

And yes, to get any where near that weight one has to look beyond the materials most of us have used.

dave
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Postby High Desert » Sat Dec 05, 2009 12:58 am

the closest thing I can personally reference is the difference with my full size pickup. With the car hauler behind it empty I get almost 2mpg better then with the 23' travel trailer. Even with a car on it which puts them at about the same weight, I still get a full 1mpg better, the only significant difference being it's lower in overall height. To my thinking these results would be similar percentage wise on a smaller scale, but maybe I'm wrong.

As for the lighter materials, it would make for an interesting exercise at the least.
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Postby artwebb » Sat Dec 05, 2009 1:46 am

I don't know about the weight making all that much differance (would depend what you're towing with so it IS relevant to the answer) but the height would IF you'r talking about a non-foldig trailer taller that is taller than, again, your TOW VEHICLE as additional height means greater frontal area, and that means more fuel necessary at a given speed, and as speed increases the drag increases not linearly but exponentialy. So, what tow vehicle, how tall, what sort of horsepower and torque? Of course, the fact that the pop-up has replaced the teardrop for most mainsteam campers is a hint and a half. The reason I don't care for pop-up is they're too prone to failure (too many moving parts) less secure from break in (a knife will unlock one) and much less cool than a tear
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Postby Arne » Sat Dec 05, 2009 9:22 am

The tow does make a difference.. If you are towing with a big pickup truck, probably not much....

Once the weight is rolling, if the road is flat, the weight makes little difference... The more hills, the more difference it will make. When I tow through the hills/mountains of w. va, There is a lot more downshifting than when I am not towing...

So, lighter is better, but convenience also counts. I don't want canvas.
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Postby dwgriff1 » Sat Dec 05, 2009 9:25 am

My tow vehicle is a small Chevy coupe. It is 62" high and even though my current trailer is quite low, it is taller than that. Width wise it is about the same.

And at 115 hp I might well be considered under powered. Still it has worked well.

It seems that many tear builders begin planning the 2nd build while working on the first. I am wondering if a 2nd build is worth the trouble.

I have pulled my tandem axle flat bed trailer with a full sized pickup and loaded or empty (the load was lumber so was not high) the MPG was not much different.

My guess is that once you pass some weight, maybe 500 maybe 800 pounds it does not make much difference in mpg.

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Postby angib » Sat Dec 05, 2009 10:19 am

A while back I worked out the extra rolling resistance from a 1,000 pound trailer weight - this is just rolling resistance, so it applies to towing on the flat. The data depends on what type of tyres are fitted to the trailer:

Bias/crossply tyres:
Extra horsepower needed at 50/60/70 mph: 2.8/3.7/4.7 hp

Radial tyres:
Extra horsepower needed at 50/60/70 mph: 2.1/2.7/3.3 hp

Now these look like tiny powers, but remember that the tow vehicle is using maybe only 30-60hp at these speeds (maybe 50% more for a big truck), so we're looking at a 5-10% increase, to tow 1000lb. I would expect fuel consumption to go up (ie, mpg go down) by a roughly similar percentage.

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Postby teardrop_focus » Sat Dec 05, 2009 12:44 pm

I like threads like this. We get to brainstorm. Benchrace, etc.

:dancing

And I'd like to set the tone of my post here with my compliments on your oak-framed, 580 lb work of art, sir! You know what you're doing.

:SG



dwgriff1

I'll restate: Would the tow vehicle get better mileage pulling a 300 pound trailer than a 6 or 800 pound one?


Of course! Especially when starting and stopping... :pipe:



dwgriff1

Would it make a lot of difference if the trailer were very flat, like a folding trailer might be?

And yes, to get any where near that weight one has to look beyond the materials most of us have used.


Like Andrew said, "If the trailer expands into a size 3 (whatever that is), then it is likely to weigh more than non-folding size 3, because the folding/sliding/magic bits weigh more than rigid bits.

So in this case smaller and lighter don't go together."





dwgriff1

My tow vehicle is a small Chevy coupe. It is 62" high and even though my current trailer is quite low, it is taller than that. Width wise it is about the same.

And at 115 hp I might well be considered under powered. Still it has worked well.

It seems that many tear builders begin planning the 2nd build while working on the first. I am wondering if a 2nd build is worth the trouble.


There's no harm in engineering it "on paper" first! :thumbsup:




I have posted elsewhere that for my first build, I'd like to use traditional teardop construction materials, i.e. plywood, mild steel and a lightweight skin. From what I have gathered from one of the first plansets from the late 1930s - 650 lbs using 3/4 ply and a massive, custom-built galley w/ ice box - and Bill Harper's claimed 450 lbs empty for his Quik N Easy, I know I can build a 4 X 4 X 9 using additional "lightening techniques" to "add" even more "lightness" and come in well under 500 lbs empty.

My 12V system's 105-amp-hour, 70-lb agm battery may take the trailer's weight through the 500 mark, but not too far over. With almost 400 lbs of my stuff including a good supply of bottled water, I hope to go down the road at 900 lbs. I hope I am being realistic; I think I can do it with a minimalistic approach...

:lol:



As you've noted, those who've been asked about what they'd change for their second (and third) builds always answer, "I'd build it smaller and lighter - I went too big and too heavy..."

My particular tow vehicle, a Ford Focus ZX3, is rated to tow 1000 lbs, but that's for the 2.0 L version with the wimpy pre-'05 front discs. The 2005-and-newer Focuses are rated to tow 1200 lbs with only a mild front brake upgrade. My car has Ford's (first) PZEV 2.3 liter Duratec engine (155 lb/ft!) and I've added the even bigger, massive SVT/ST170 Focus brakes, so I hope that keeping the entire towed package at 900 lbs will result in a more-or-less understressed arrangement.





dwgriff1

I am sure it would get better mileage, but would the margin be enough to justify the search for the lighter weight solution?


A lighter trailer that sleeps a taller person such as yourself will have to be built entirely of luan (like Roly's) or one of the popular composites, as Ageless has just noted.

In addition to the posts I hope your thread here will generate, there're several composite-build threads posted. You may have already seen most of them.

:thumbsup:
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Postby Ageless » Sat Dec 05, 2009 1:11 pm

Well, if cost be damned; you could fabricate a composite frame even lighter than aluminum. Back in the 80s, Ford built a racing engine using composites; only steel parts were the valve springs.
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Postby starleen2 » Sat Dec 05, 2009 7:09 pm

Ageless wrote:Well, if cost be damned; you could fabricate a composite frame even lighter than aluminum. Back in the 80s, Ford built a racing engine using composites; only steel parts were the valve springs.

I've seen a lightweight trailer constructed out of Cardbord tubing encased in fiberglass. The tubing was the type used for upholstery fabrics :thinking:
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Postby dwgriff1 » Sat Dec 05, 2009 8:39 pm

Right now my thoughts on construction are way off the page. The reason for the thread was to check with THE engineer and the engineers to see if the lighter yet idea made any sense.

I am not totally sure yet. The big bugaboo is wheels and axle.

No construction details yet, but I continue to work and think. I'll make a model, maybe 2 or 3 inches to the foot scale before I begin any actual work.

Right now I am sketching and thinking.

And thanks for the input all of you.

dave
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Postby Stealth TDI » Sun Dec 06, 2009 8:31 am

Hello,

One point that's been just barely touched is frontal surface area. With the exception of braking and initial acceleration, I tend to believe a low, narrow 1000-lb trailer would tow better than a larger 500-lb trailer. This assumes the TV is a car. If it's a truck, then it's probably a wash. ;)

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Postby bobhenry » Sun Dec 06, 2009 8:53 am

Stealth TDI wrote:Hello,

One point that's been just barely touched is frontal surface area. With the exception of braking and initial acceleration, I tend to believe a low, narrow 1000-lb trailer would tow better than a larger 500-lb trailer. This assumes the TV is a car. If it's a truck, then it's probably a wash. ;)

Scott


Head wind can be a problem too ! The barn does down the road fine behind my 2000 Suzuki esteem

UNTIL...

I was heading home 1 day in a 35 mph head wind . Now combine that with the 50 mph I was trying to maintain thats 85 mph. I was running out of ponys under the hood. So out of 5th and into 4th and all was well again.

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"Aerodynamic as a barn"

You can build a 200# box and it will still require more h.p. to pull it if it is just a slab faced unit. I think the new roswell is one of the most aerodynamic shapes we have seen on this board in some time. Cargo trailers are opting for the Vee nose configeration. These are happening for a reason but it's not new , Len posted just today picture of a 1938 airstream larger tear. Round nose and a slopeing front roof for aerodynamics so maybe we should reconsider this configuration for a future build.

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Thanks to Len ( I stole the pic)

I think I just found out where the T@B got it's rear design. Image
Last edited by bobhenry on Sun Dec 06, 2009 9:34 am, edited 1 time in total.
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Postby PanelDeland » Sun Dec 06, 2009 9:17 am

I didn't notice anything on "cost to advantage" on this.My thought is that even an ultra light 300# trailer is not going to be towed enough to make up the difference in cost.If you used the trailer 50 weekends and a couple weeks a year,Maybe.But if you use it that much,than a larger TV and trailer would be required for comfort.
However discussions like this breed ideas that may be used in other applications.With the avaiability of modern lightweight materials and careful design and planning,300# is not unobtainable.Maybe a composite skin of foam(as stated above) or cardboard and fibreglas or epoxy coating(much like interior doors) with no gallery and the lightweight frameless design.
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Postby bobhenry » Sun Dec 06, 2009 9:31 am

PanelDeland wrote: However discussions like this breed ideas ..............
:o

So I need to install a large hay mow door and a couple small windows in the rear to exhaust the incoming air and thereby reducing frontal exposure ........... :rofl: :rofl: :rofl2:

Flow thru dynamics a whole new topic ! ??????
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