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11-12-2015, 06:39 AM
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#21
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Rivet Master
1971 21' Globetrotter
Currently Looking...
Currently Looking...
Currently Looking...
Arvada
, Colorado
Join Date: May 2006
Posts: 3,530
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As this has been nothing but an idea bouncing around inside my head and I have have not actually done it, (I don't think it has been done by any forum members) some engineering will have to be done to figure out how thick a flat plat would have to be to replace a channel. Or just add more outriggers
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11-12-2015, 05:50 PM
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#22
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3 Rivet Member
1971 18' Caravel
Nokesville
, Virginia
Join Date: May 2013
Posts: 104
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I think more out riggers has been discussed at length and adding them is sort of a forgone conclusion. Channel or angle would be easy on the sides, it's the ends that bother me. In such a short trailer the ends must provide the majority of the strength. Thanks again for your patients and advise.
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11-12-2015, 06:51 PM
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#23
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Rivet Master
1986 25' Sovereign
2008 F350, 6.4L diesel
, Oak Harbor, WA
Join Date: Sep 2015
Posts: 605
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Forums are great for discussing new ideas. I would guess that your frame is so bad that you need to take the skin off and build a new trailer. Frame repairs with the skin on are easy to do.
Redesigning can be very challenging, plenty of design decisions that aren't apparent until you change the design. It is amazing how just moving one thing can ripple around the whole layout.
Good luck.
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11-12-2015, 07:16 PM
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#24
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Rivet Master
1971 21' Globetrotter
Currently Looking...
Currently Looking...
Currently Looking...
Arvada
, Colorado
Join Date: May 2006
Posts: 3,530
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Yup, it's the corners that's the challenge.
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11-14-2015, 05:41 PM
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#25
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Rivet Master
1981 31' Excella II
New Market
, Alabama
Join Date: Sep 2011
Posts: 6,145
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A perimeter frame would be connecting outriggers together and yes the corners would be hard without hydraulic benders. The object here is to provide a real structure for the shell and for it to be supported every few inches instead of at a few points at the front and back and at the tip of an out rigger. Yes it is overkill but you would not need to worry about a bike hanging off the back of the trailer.
Perry
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11-15-2015, 06:30 AM
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#26
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Rivet Master
1981 31' Excella II
New Market
, Alabama
Join Date: Sep 2011
Posts: 6,145
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The problem with the Airstream is that it is an Aircraft fuselage that has been cut in half. The floor and frame are an attempt to replace that missing half. The shell is really strong because of a large moment of inertia. The frame is pretty strong but not as strong as the shell. If you can keep both of them from moving relative to each other, you make a very strong structure. The out riggers only contact the shell in a few places and since they are cantilevered, they don't have much strength. At most they support the floor at keep the shell from bulging out when stressed. Better support at the back and front all the way around the corners would probably be the easiest way to gain strength. We had one guy on here, Steve, who did something like this and I think another guy who actually built a perimeter frame. I will see if I can find some of these links and post them.
Perry
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11-15-2015, 02:40 PM
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#27
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3 Rivet Member
1971 18' Caravel
Nokesville
, Virginia
Join Date: May 2013
Posts: 104
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Thanks Perry, I am a relative novice at all this and am definitely standing on the shoulders of Giants who have tons of previous knowledge, skills and most of all experience. I am absolutely going to have a frame built and want to try and get it right the for the first and hopefully the last time. I am currently leaning toward an 8 inch main rail with similar cross members. More outriggers and a top plate that will act as a perimeter frame. I will need to solidify a plan prior to talking to the trailer frame builder so long this conversation advice and sedate is very helpful.
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11-17-2015, 03:43 PM
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#28
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Rivet Master
1981 31' Excella II
New Market
, Alabama
Join Date: Sep 2011
Posts: 6,145
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Depends on what you plan to do with the trailer as to how crazy you go on beefing it up. I have not had problems with my center bath. Rear bath might be another issue. Newer trailers had better full box beams. If you do what you are talking about, you could probably have a back porch on it or a big storage box. You need to be aware of tongue weight and beef up axles for the weight of the heavier frame. Good luck.
Perry
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11-17-2015, 04:28 PM
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#29
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Rivet Master
1972 31' Sovereign
1975 31' Excella 500
Currently Looking...
Benton
, Arkansas
Join Date: Mar 2013
Posts: 5,868
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Replacement frame
An eight inch main rail is crazy overbuild in my opinion.
I see a six inch rail as overbuild, but more in the ballpark.
I would make the rails out of 5" x 2" rectangle tube if I was building from scratch.
Brevi tempore!
__________________
The fact that I am opinionated does not presuppose that I am wrong......
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11-17-2015, 04:32 PM
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#30
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Rivet Master
1969 29' Ambassador
brooksville
, Florida
Join Date: Nov 2008
Posts: 1,270
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Yes but they hold big tanks!
__________________
Not all those who wonder are lost.
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11-19-2015, 09:39 AM
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#32
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Rivet Master
1972 31' Sovereign
1975 31' Excella 500
Currently Looking...
Benton
, Arkansas
Join Date: Mar 2013
Posts: 5,868
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Quote:
Originally Posted by Silverflames
Yes but they hold big tanks!
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That is a fact. I do wish I had installed bigger tanks. There are ways to accomplish bigger tanks without running 8" the full length of the trailer.
Brevi tempore!
__________________
The fact that I am opinionated does not presuppose that I am wrong......
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11-19-2015, 09:49 AM
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#33
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Rivet Master
1981 31' Excella II
New Market
, Alabama
Join Date: Sep 2011
Posts: 6,145
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My center bath tanks hang way down below the frame. Make a tank pan.
Perry
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11-21-2015, 04:31 PM
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#34
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3 Rivet Member
1971 18' Caravel
Nokesville
, Virginia
Join Date: May 2013
Posts: 104
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So I am leaning toward the following:
8 inch Structural C for the main rails, with 5 similar sized I beam cross members (poss a C in the front and rear?) Originally there were 6, but I would need to remove one to accommodate the new black and grey tanks on both sides of the axle. Fresh water tank will remain forward of that, same as original location.
More out riggers (every 6-12 inches???) 5 inches deep in order to maintain the original belly pan configuration (the deeper rails will be exposed 3 inches below the wraps).
Top perimeter plate 6 inches wide, 0125 thick (jimgolden, aerowood)
Similar original A frame with a spare tire mount under the front.
Extend the rear by 12 inches to accommodate a slightly larger trunk and a small separation between the back of the trailer and the trunk. This will help to address the problem of water accumulating or running down the back and leaking into the skin (I will also address the seam in that area by extending the rear panel to a belly wrap)
There has also been some thinking of adding a pneumatic or hydraulic leveling system. Pillars in each interior corner of the frame??? Who knows.
I am concerned about tongue weight, how heavy do the axle need to be (5000# dexters). Mostly tech stuff as I am no en-guh-neer or even Mechanically inclined.
All of this is speculative at best, though I will have to decide something soon.
Any thoughts.
Thanks again for all the suggestions.
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11-21-2015, 04:45 PM
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#35
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Rivet Master
1972 31' Sovereign
1975 31' Excella 500
Currently Looking...
Benton
, Arkansas
Join Date: Mar 2013
Posts: 5,868
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Well, I have a 45 foot flatbed trailer, the frame is made of 8" I-beam, it uses 4" crossmembers every two feet.
It weighs in excess of 7,500 pounds...
I expect a frame like you described will weigh between 4,500 and 5,500 pounds.
Are you going to haul rocks in that thing?
Imho, the frame you propose is ridiculously overbuilt.
You might consider how much that 10 to 15% tongue weight is going to be.
Brevi tempore!
__________________
The fact that I am opinionated does not presuppose that I am wrong......
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11-21-2015, 04:55 PM
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#36
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Rivet Master
1972 31' Sovereign
1975 31' Excella 500
Currently Looking...
Benton
, Arkansas
Join Date: Mar 2013
Posts: 5,868
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There are pluses to a deep frame, if I wanted a deeper frame I might go eight inches, but it would be thinwall tube, not thickwall.
Brevi tempore!
__________________
The fact that I am opinionated does not presuppose that I am wrong......
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11-22-2015, 07:01 AM
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#37
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Rivet Master
1981 31' Excella II
New Market
, Alabama
Join Date: Sep 2011
Posts: 6,145
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Ya need to have more than a plate between the outriggers. This might be hard without hydraulic tubing benders etc. A plate with some gussets might be all you can fab on the corners but angle works fine for the straight sections. No having to put the floor under the walls has its advantages.
Perry
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11-22-2015, 07:29 AM
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#38
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Rivet Master
1969 29' Ambassador
brooksville
, Florida
Join Date: Nov 2008
Posts: 1,270
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What about having the 8" c channels formed out of 1/8" galvanized sheet metal? The original frame was about this thickness.
__________________
Not all those who wonder are lost.
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11-22-2015, 01:32 PM
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#39
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Rivet Master
Vintage Kin Owner
1977 31' Excella 500
Berkeley Springs
, West Virginia
Join Date: Sep 2005
Posts: 1,638
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Perry,
By a plate around the outriggers, I meant essentially a 1/8" thick (1/16" would probably suffice) plate that is 6" wide, cut to the outside contour of the trailer, going all the way around.
To this flat plate, you would attach your U channel. With the U rigidly attached to the plate, you now have a big L with a ton of Moment of Inertia. Very stiff. You can attach the shell to the U, and let the outer edge of the floor bear upon the remaining width inside the U.
In fact, I'd change the floor as well. I'd do it like Avion does, with three layers: 1/2" plywood bottom, 1.5" spacer (with a cross piece every 4' and insulation filling the gaps otherwise), 1/2" plywood top. You'll lose a little bit of headroom, but the result is a very stiff floor that is insulated. It works well for the Silver Sister, so would do well here....as long as you're not 6'6" tall
As for the curved portions, I'd recommend grinding the flat plate to a width of 5 15/16" wide, taking the 1/16" off the outer edge on the rounded areas. Then, get a strip of 1.5" tall by 1/16" thick steel and weld it to the outside edge, making an L in the corners. So, use the U channel on the straights, have the outer edge 1/16" steel piece welded to the corners match the outer portion of the U, and you have a continuous vertical web 360 degrees all the way around the outside.
It would be a little harder to form a 1/16" inner portion to match the U channel out of plate, but it could be done with spacer blocks without too much trouble.
On the outer plate, I'd weld it solid on a short section of straight. Then, for every 3", I'd bend it into place and weld, then bend the next 3" into place and weld, and keep going all the way around the circumference.
Anyway, I think you, AeroWood, and I are all saying essentially the same thing. Put a stiffened "perimeter frame" atop the outriggers, have something with it to carry the floor, and bolt the shell to this perimeter frame and let the floor bear within. This in addition to a proper main frame and it'll be goodness.
If he does this, he will be Gold
__________________
- Jim
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11-22-2015, 04:14 PM
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#40
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Rivet Master
1971 21' Globetrotter
Currently Looking...
Currently Looking...
Currently Looking...
Arvada
, Colorado
Join Date: May 2006
Posts: 3,530
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FYI , your banana wraps will no longer work with an 8 inch tall frame. IMHO an 8 inch tall frame would be grossly overbuilt for a Caravel. You could carry a skid loader inside you trailer.
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