Trailer heavy on one side!

[overlander63]

The frame "hole punching" was a weight-saving measure in the mid to late 1970's, with usually less than desirable results. It was one of the reasons coaches of that era have the rear end sag issues. Remember, this was around the time of the first gas crisis, and Airstream was trying to make their coaches towable by as many vehicles as possible.

[LI Pets]

Originally Posted by overlander63

The frame "hole punching" was a weight-saving measure in the mid to late 1970's, with usually less than desirable results. It was one of the reasons coaches of that era have the rear end sag issues.

Why do you say that?

If the holes were engineered correctly the overall strength is unaffected I would think.

[Minnie's Mate]

The issue with rear end sag was more of an issue with reduction in frame member size/depth than hole punching would have created. Yes, the hole puching does reduce weight, but as an architect, one thing I do know is that the strength of a beam is relative to the distance between the flanges not the amount of material in the web member itself. The web stabilizes and stiffens the flanges and keeps them parallel, but doesn't add a lot to the strength of the beam. Think parallel cord floor trusses. These are the flat "W" trusses used to support long span floors like in malls and flat roofs in warehouses and many other buildings. There is relatively little metal material between the flanges compared to the depth of the floor truss, yet they suppport a tremendous amount of load compared to their own weight.

However, when you decrease the distance between the flanges, you significantly decrease the beam's structural strength. This is what happened when Airstream reduced the depth of the frame members. Each was a small beam that supported the contents of the trailer above. IIRC, Airstream reduced this depth by 20-25%. This is what led to rear sag. Yes, I know part of the support of the floor was suspended by the monocoque design of the Airstream, but this whole assembly sits on the frame.

And yes, as long as the holes are properly spaced and not too large in diameter for the depth of the web, the strength would not be affected.

[LI Pets]

You took the words right out of my mouth

[Action]

The hole punching is done for weight savings. (So was the support spacing, with not so good results) And I would guess the hole punching only amounts to something like less than 100 #'s at best. Much less than 1 BD. And over many many miles, the savings adds up to lots.

Wouldn't you rather tow 2995 pounds or would 3095 be better. Getting all that weight moving each time one accelerates and then stopping all of it takes some energy. Over a weekend, it makes little to no difference. Over the life of the trailer/tow vehicle it adds up.

Why else would Airstream punch out the holes? (BTW in the automotive arena, design engineers get really excited with saving ounces for the same reasons. For in a daily driver the weight is spread out over many many more miles or use cycles.)

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[GetOutDoors]

One may question the reasoning for which Airstream reduced the weight of the frame by punching holes. . . And for using 5/8ths ply instead of 3/4 in the floors. . . And for using 3/8ths ply in cabinets instead of 1/2 . . .

Depending on what you are examining or working on, it may appear that Airstream took the "less-than-logical" way out.

Once you've rebuilt one of these from the ground up, you realize that a little weight savings here and a little there will add up to a lot overall! This is one reason Airstreams are popular! Take the Bambi for example: they are hot on the market in part because they are light weight and can be towed with mid-sized SUV's. Which means a family can have and tow a tt without the need of owning another vehicle that would not be used otherwise.

Calvin

[Chopper]

The reason my TV is a Diesel Ram is that my "lightweight" fiberglass Boler killed our original family van, a '95 Windstar, and went to work on the transmission of the replacement vehicle, a '99 Infiniti QX4.

The Boler was supposed to be 3000# empty, but we didn't know better and loaded it up fully until it was probably over 5000#. We lightened up a little after the initial wrecking of the Windstar, and went to a weighstation and we were at 4300#. Still, on that trip through the Rockies, fully loaded semi's were passing us on the uphill in the QX4. Which is why we finally got Big Blue.

What made up the weight? All the house extras went into the Boler, including a full set of silverware (eight person setting), all our extra pots and pans (including the heavy cast iron ones), a spare microwave (heavy duty one), firewood, two buckets of tools, full water tank, extra bedding, extra mattresses for comfort, a pile of extra dishes, portable chairs, outdoor games including a heavy bocce ball set, and books & magazines of all types, and kid's toys, and a portable TV that we never used...ouch...we learned that the TT is not a cabin. Maybe we should see it more as a backpack...keep it light!

Cheers!

[bhayden]

Wouldn't this make the trailer heavy on one side?

[Action]

One thing you all have discovered, RV's gain weight with age!

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[ROBERTSUNRUS]

Originally Posted by Action

One thing you all have discovered, RV's gain weight with age!

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Hi, I think that goes for people too. Well, I know I'm up a bit too!

Bob

[ROBERTSUNRUS]

Originally Posted by bhayden

Wouldn't this make the trailer heavy on one side?

Hi, only if those are real bricks?

Bob

[Chopper]

The weight of all the material I removed from the interior of the Argy (the original cabinets/walls/gaucho) is surprisingly light. I've filled a utility trailer full with the panels and it's a big pile, but not very heavy. In the process of taking the walls apart, I've found out that they are incredibly strong. I now know that the interior skin of the Argy is aluminum so the rivets that hold in the C-channels and upper cabinets make for a strong connection. I'll take these lessons from Airstream during my rebuild, but I fear that my experience more on the house building side will result in a heavier coach.

What's the experience out there by those who have rebuilt? Does the final trailer feel heavier? I see a lot of hardwood floating floor finishes that must weigh a bit, especially in light (no pun intended) of the comments made above about attempts to lighten up the coach with holes and thinner members even.

Cheers!

[Action]

The original asbestoes tile was not light. Compared to todays flooring it may be a toss up.

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[Minnie's Mate]

Laminate floors and hardwood floors are heavier than the original tile floors and the new sheet vinyl (and real linoleum) and carpets. Unless you get into something really exotic like a rubberized floor, you should be lighter than the VAC tile floors or aforementioned laminates and hardwoods.

[369goose]

Following

[Action]

Originally Posted by 369goose

Following

Your are following a 4 year old thread.

Good luck

Action

[OTRA15]

Originally Posted by action

your are following a 4 year old thread.

Good luck

action

14

[Action]

I lost the one key. How could that happen?

Action

[GCinSC2]

Action,

You’re keyless. But that beats clueless.

Blame the humidity.

Gary

[jaybauman]

Originally Posted by Action

I lost the one key. How could that happen?

Action

Inflation? Two is the new one.