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-   -   AS brochure length and weight mysteries (http://www.airforums.com/forums/f463/as-brochure-length-and-weight-mysteries-69871.html)

carl28 09-25-2010 09:44 AM

AS brochure length and weight mysteries
 
Hello All

I am new here - have been studying the airstream floorplans and specs for new trailers, with consideration to matching the tow vehicle, and have discovered some things I cant tie down - would appreciate any comments:

1. The specs seem to indicate that “length” of the trailer is from the coupler to the rear bumper - is this really the case I can’t find any detail drawings anywhere. I ask this because:

2. On the brochure, the 28’ floorplans are speced as being 1” shorter than the 27s. But the floorplans seem to indicate that the 28 is in fact longer than the 27, not shorter. This is especially noticeable for the international page. This is not a screen or a printing issue because the plans are comparative on the same page. I put little marks on a piece of paper and the plans seem to be shown at the same width on the page (or screen) within a millimeter or so. So I dont think that someone has just imported these floor plans as images at the wrong scale on the page. This applies to both the overall trailer length and the length of the coach walls themselves.


3. The 28 ft models (27’-11”) seem to have a longer camper enclosure and a comparatively shorter A-frame / hitch area. Is the A frame shorter here? Does that affect anything with towing or balance? It looks as if the A frame is squished a bit, or the shell is overlapping what used to be a shorter frame. - it seems more noticeable for the international page floorplan. If this is the case, there is actually (comparatively) a more useable floorplan space in the 28 than the 27.


4. The 28 ft is listed as only being about 100 lbs heavier dry UBW than the 27s, yet it looks like more camper and yet is speced 1" shorter, making me wonder more. The blackwater tank is 2 gallons less than the 25 and 27.....
...

5. I understand the tongue weight specs - but the overall vehicle weight listed for the 28 ft is really about the same as the 25 and 27 - but it has less carrying capacity by a more significant jump comparatively to the 23s and 25s - so perhaps this is 28 ft is in reality a bigger coach on the same 27 ft trailer frame.



this 28 seems like a different animal - thoughts????
 thanks in advance, trying to justify that hitch load some in the midst of all this

carl28 09-28-2010 03:47 PM

OK - no one is responding - I think I have determined that the posted pdf for the airstream website is just improperly scaled, while the web page version of the same floorplan (international 28) seems to be correct.

If anyone has any notes regarding how the different A frame dimension at the front of the trailer might impact hitching or towing that would be great

still curious if this is a different frame altogether from the 27s

funkill 09-28-2010 04:04 PM

Sorry Carl, can't answer your question personally but be patient. Sometime takes a day to get flooded with replies!

I'm surprised that a 27' and a 28' are both offered. heck, I never even heard of a 28'. My 27' is measured tongue to bumper - but don't know it's exact measurements of cabin - just thought it to be in the 25' to 26' range. Sounds like I'm a slacker - but that is definately not the case. I surprise myself at my priorities sometimes. Ask me tire size and I can give you all the details... well, I could - back when I was doin' the research.

Laura

slowmover 09-28-2010 06:11 PM

(Answered this in your other thread). Published figures (even length) is open to interpretation. Center-of-hitch-ball to rear bumper outermost edge is trailer length (in decades past some trailers were measured by body exterior only, or, even just interior floor length).

Weights are absolutely NOT reliable except from a certified scale. Even trailer to trailer differences (options) can make significant weight differences.

Try either adding 700-lbs of personal gear past full fresh water and propane (plus several hundred pounds for options); or try deducting about 5-700-lbs from trailer GVWR to get guesstimate into focus. So long as one keeps in mind that all guesstimates are essentially worthless it's mental play until numbers can be obtained from real examples.

Conservative estimates are always high. VERY high, to be reasonable as you play around.

Good luck.

.

carl28 09-28-2010 11:53 PM

thanks for these responses - my original question was a little bit involved so I was sort of blaming myself not others. Its actually a tundra question in disguise - I havent yet seen a 28 footer in person...

I have to assume if you loaded up the trailer on the 28, the hitch load would go up about the same proportionally as the 27s or even the 25s, since the plumbing, cabinets, and tanks are over the wheels more or less in the same places.

CanoeStream 09-29-2010 07:41 AM

I agree that you've got to treat listed weights as a starting point -- even for a new, unloaded unit. Fresh water is usually right at the axle; one does tend to tow more with this full and the others empty ... but not always. Moment arm calculations (hardly necessary) would suggest that adding antisway/weight distribution gear and propane at the A-frame would add mostly to hitch weight.

Don't assume the catalog illustrations to be scaled properly -- and certainly not one to the next. I would think that A-frame sizes are all similar enough and these wouldn't lead to reporting trailer lengths unlinked from cabin length.

The convention for measuring is bumper to ball. And the stated length is derived from tossing away fractional feet; eg, my 25' 11" Safari is called a 25-footer. Except there was some model sequencing that led the new 27' 11" Internationals to be called 28-footers. And later yet, the 28' long (per the catalog) FB International was introduced. That was called the 27-footer to remove any confusion. :blink: I know ... makes no sense. I'm not sure the 28' or 27' would measure any differently in the real world. Overall significance is not worth tangling with.

I hope you can walk through both floorplans. That's how your preferences should guide you. :flowers:

Aviator 09-29-2010 12:31 PM

I keep reading that the length of our Airstreams is from ball to bumper. That said, our 1997 34' trailer is 35'11" from ball to bumper.

steverino 09-29-2010 01:33 PM

Just as a point of reference; data fresh off of a CAT scale for my 2010 FC 27FB. Tongue weight, for the trailer loaded as we normally tow (full fresh water tank, full propane, normal assortment of personal items, bedding, camping equipment, etc) was 900 lbs exactly. Which is up 109 lbs from the published spec. About 40 of that weight can be attributed to tools and supplies that I stow in the front locker. Don't know if the 28 has a front locker; it might be under the bed in the rear.

As far as tongue length, I think it's the same for 27FB and 28. they are equipped identically with respect to power jack, propane cover, and battery box.

carl28 09-29-2010 08:49 PM

steverino

thanks for this post! This confirms what I have been wondering, the tongue is probably going to be more than what I am trying to guess, but not outrageously so, based on specs for the 28. I assume this is the real tongue weight not the WD number of course - I dont know how you would really weigh that one anyway - Thanks again. You can see my other thread at "sell my new tundra?..."

steverino 09-29-2010 08:59 PM

I got 2 cat scale readings - one with rig hitched with WD, and one with the truck alone. the net gain in weight on the truck's steer and drive axles when hitched, is what I call tongue weight.

carl28 09-29-2010 11:22 PM

OK - thanks
that means the non-WD weight is more like 1200 lbs which makes more sense loaded up, and the 28 will likely be even heavier. So that really puts a twist on things for my setup. (You dont have some mega 200 lb hitch do you?)

thanks again this is a real number I think will make a difference for my plans

steverino 09-30-2010 12:25 AM

Surely there's more expertise here than me, but isn't what counts is the weight applied to the truck when hitched up and WD installed? Yes, there might be 1200 lbs on the tongue jack when unhitched, but that's not the weight the truck bears when hitched up...

slowmover 09-30-2010 08:36 AM

Quote:

Originally Posted by steverino (Post 901455)
Surely there's more expertise here than me, but isn't what counts is the weight applied to the truck when hitched up and WD installed? Yes, there might be 1200 lbs on the tongue jack when unhitched, but that's not the weight the truck bears when hitched up...

Depends on how it is distributed (which is why a separate TW reading is called for), which can vary according to a particular TV, AND by TV manufacturer recommendations. Trailer loading can also, obviously, change things, so a TW (empty weight) is the background for any changes (as all changes tend to be additions).

Hitched (only) is another TW, and any application of leverage are other TW's (differing amounts of force applied via bars).

carl28 09-30-2010 10:24 AM

my assumption is that theres no guarantee you are going to get exactly 2/3 of weight from the WD hitch on the TV. And then I agree the system is changing as you use up water or move cargo on a trip.....

Also the non-WD hitch weights are kind of useful to get some perspective on all the various numbers, if you are willing to absorb them - dry vs wet vs non-WD vs scaled vs the manf stated weights.

2airishuman 09-30-2010 03:23 PM

hi carl

welcome to the forums

and good4u trying to sort ALL of these issues, PRIOR to buying.

i see your questions (in these 2 threads) lumped into 3 general categories...

1. trailer specs, build issues, structural differences and so on...

2. w/d in regard to hitches, calculating vs measuring tongue weight and how that all relates to tv selection.

3. tv ratings, matching tv to trailer and meaningful modifications to the tv that may enhance real world towing.

the tangential issue related to #1 is "what size/floorplan stream do i need"

the tangential issues related to #2 are many and will eventually involve SELECTION of a hitch apparatus.

the tangential issues related to #3 are also many but for now focus on axles, springs and supporting payload.

is that a reasonable summary?
_________

for now this post focuses on #1 with a tiny bit on #2.

#3 and most of #2 will go into your OTHER thread.

http://www.airforums.com/forums/f463...gle-69998.html
_________

u have correctly concluded that the floor plan graphics are improperly scaled.

the LISTED lengths are correct the 27 is longer than the 28.

a/s is well know for doing this, for example classic 30s and 31s are exactly the same length.

they differ by floor plan and the 31/30 tag was a simple way to make that distinction.

the actual FRAMES on 27s and 28s are different.

the 27 as a rear door model has different outriggers and structure around the steps/door.

the 28s as a front door model has specific outriggers and support around the door/step location.

they MAY be other differences, like # of cross braces, outriggers and placement of the axle cut outs.

a/s doesn't make the frames, leland does,

and since heavy things are in different locations it is not UNreasonable to assume frames differ.

the gvwr are diffent, so u might also ask IF the axle ratings are different for the 27 vs 28.

i had a similar set of questions back in 05 when sorting out an order,

http://www.airforums.com/forums/f296...-up-15259.html

http://www.airforums.com/forums/f296...sic-15300.html

http://www.airforums.com/forums/f296...res-27055.html


and only cleared things up, after a few email exchanges with a/s tech/customer support.

the dealer also hounded them about these questions, since i was unwilling to BUY without the details.

LUCKILY 4 me, no one responding here (trying to help) suggested a DIFFERENT SIZED UNIT.

knowing exactly what size/floor plan i wanted was a done deal, so suggesting smaller would not have been helpful.

the printed materials, the website and the actual SPECS for any given unit or year (especially new) don't always MATCH UP.

often the factory web site differs from the dealer pamphlets.

1. contact tech support with your questions about frame/tongue issues, they will tell u the differences between a 28 and 27.
_________

ok now a few notes on #2 above, the w/d issue.

a/s has 4 a long time UNDER estimated tongue weight, leaving out spare tires, lpgas and options.

recently they've started including spare tires and appear to be TRYING to improve published estimates.

still the only real way to know is weighing the tongue, loaded, gased, watered and so on...

steverino' report doesn't mention IF w/d was engaged, and is indirectly estimating tongue weight (that's not a bad thing)

i understand U are interpolating that data to arrive at a higher real tongue weight.

that's fine except the notion of 1/3-1/3-1/3 or 2/3-1/3 is NOT based in reality.

it may have been at one time (i doubt it) when single axle, short trailers and long sloppy sedans were the norm...

the goal of w/d is to RESTORE steering axle loads NOT distribute the tongue equally over all axles.

we can dig further into this later but for now, don't assume a 27-28 has a 12-1300 lb tongue.

cheers
2air'

carl28 09-30-2010 04:00 PM

2air

thanks for you methodical post. I will absorb this for awhile and perhaps call AS and see what they can say. My guess is the 28 is just a different animal altogether, frame too. But since I wont really know till I get on the scales and on the road for awhile what it means, I will simply go after the floorplan I want - with some wiggle-room-likely-to-be-required in the loaded weights I experience

2airishuman 09-30-2010 04:33 PM

Quote:

Originally Posted by carl28 (Post 901690)
... My guess is the 28 is just a different animal altogether, frame too...

we agree on this.

cheers
2air'

JFScheck 01-04-2011 10:50 PM

Scales be our best friend....


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