Westronics
Redmond, WA
Moderator
Joined: 08/07/2002
View Profile
Good Sam RV Club
 Offline
|
rcase13 wrote:...No problem I guess I just assumed that there would be studs every 16" like a house... My son and wife will spend time in the back while on the road and I just want to be clear in my mind how these things are constructed. Asking the dealer these questions did not give me warm and fuzzies... They told me they were safe and I would never have wood rot...
Oh, I see the initial source of confusion for you - the dealer's sales person. Never, ever expect correct answer to any technical question, no mater how trivial, from the sales person. They sell - that's what they do. If they are very good, they can sell anything, even when they know very little about it.
So, back to safety. For the most part, you family in the back is very safe (assuming seat belts are used) mostly dues to the weight of the MH. Any movable object you might hit just gets pushed out of the way - and anything small (say, up to an SUV) that hits you gets stopped by your bulk.
Cabinets, etc., don't usually fall unless the accident is extreme in which case, frankly, things get BAD in a hurry regardless of house construction.
For me:
1. I know I have good basic construction, so I don't spend much time worrying over that.
2. I drive knowing I am driving around over 6 tons of vehicle - and am appropriately extra cautious.
3. I drive knowing I am driving over 25' of vehicle - and am appropriately extra cautious.
At all times I remember all my defensive driving lessons. They key lesson was one I learned when driving a commercial bus - most accidents are preventable. Assigning fault is only about figuring out who pays - just because you are not at fault does not mean you could not have prevented the accident.
But... I am drifting off-topic.
|
fisher60
Plant City, Florida
Senior Member
Joined: 03/23/2006
View Profile
Good Sam RV Club
Offline
|
I found aluminum studs in my rear beroom walls and cab over front window.
'01 Dutchman Express 28A, Master Tow, '06 Tuscon, '05 Honda VTX 1300
Good Sam Life Member
|
tatest
Oklahoma
Senior Member
Joined: 05/14/2005
View Profile
Offline
|
Most modern, mass production type C motorhomes have no framed walls. They are laminated sandwich panel construction, with metal tubing reinforcements in the wall. The strength of each wall derives from the lamination of skin materials to the foam core, not from framing.
The body is then assembled by attaching side panels to the metal floor frame, rear panel to sides and floor, then roof to the walls. Where there is some variation, some manufacturers frame and cover a roof on top of the walls, others (like Winnebago) build the roof also as a single piece structural sandwich.
People may describe RV wood studded wall construction anyway they want, and say what is wrong about it, but framed construction is used in the top-ranked type C brands: Born Free, LazyDaze, and Bigfoot; wood framing in the first two, metal in the third. Another high-end manufacturer (CoachHouse) builds its body as a one-piece molded plastic shell, like the hull of a fiberglass boat.
Some brands of towables (e.g. Carriage, Newmar) build a metal framed wall, and cover it, some fastening to the studs, others laminating to insulating materials. Some makes of type A motorhomes (Holiday Rambler, Newmar) use metal framed walls, and cover them; Newmar even builds its walls on top of a wood-framed floor. But most mass production type A manufacturers also use laminated sandwich walls, a technology pioneered by Winnebago in the late 1960's.
edit:
Can't emphasize this enough. The welded aluminum framing inside the sandwich walls is not the primary source of strength. The frame serves to add torsional stiffness (so the sandwich doesn't warp like a potato chip) and provide places to fasten the panels together. The tubing is not full wall thickness in most places, most often 1 inch inside a 1 1/2 inch wall, or 1 1/2 inside a two-inch wall.
The wall strength comes from the wood-foam-plastic sandwich (similar to construction of a composite aircraft wing or fuselage shell, or a composite helicopter rotor blade). These composite walls have about 10 times the strength, against bending, flexing, or side impact, of a wall framed to equivalent thickness using metal studs. The best of both worlds would be a stressed-skin composite on a framed wall, but you won't find that in a type C.
The sandwich construction is also the potential weakness. Crash into it, you may have to replace the whole wall. Let it get wet inside, the wooden skins will delaminate, making the walls delaminate. The result is not just ugly looking, the wall loses much of its structural strength, and you may not recover full strength by gluing the wall back together.
* This post was
edited 08/24/09 04:28pm by tatest *
Tom Test
Itasca Spirit 29B
2001 Ranger Edge
|
rcase13
Charlotte
New Member
Joined: 07/28/2009
View Profile
Offline
|
Thanks that makes it pretty clear. Not so upset now that I am not seeing 16 on center!
I assume the plywood sandwich is strong enough to hold a cabinet with a microwave in it. Or are the cabinets screwed into an aluminum stud?
|
frankdamp
Anacortes, WA
Senior Member
Joined: 05/04/2005
View Profile
Offline
|
rcase:
Our last rig was a 1985 Fleetwood Jamboree "Spirit", 26' Class C. It was unusual in that the body frame, aft of Ford's bit, consisted of three steel tube hoop frames. The sales material suggested the tubes were rectangular cross-section, maybe about 4" fore and aft and 1" side-to-side. One was just aft of Ford's cab, a second one was about 1/3rd the way between the entry door and the back, and the third one formed the rear cap. The walls were fibergalss on the outside, structural styrofoam and then lauan mahogany glued on to form the inside wall. I found some rot alongside the bed on the sidewalk side and was able to use the middle and aft frames to attach a fix.
It must've been an expensive rig to build, because it was only made by Fleetwood for one model year. I think the design was sold to the Canadian manufacturer that made the Telstar. They sure looked familiar! Even their Class A version has the same cross-section.
As it had a 1985 460 engine with all the carburator-related issues (air pumps, warped manifolds, rotten gas mileage) we didn't keep it very long.
Frank Damp
Anacortes, WA
|
|
|
McZip
Wisconsin
Senior Member
Joined: 11/17/2008
View Profile
Offline
|
Tatest, Great post and info. Thanks!
Safety was the main reason we had Turtle Top Bus build our new steel cage Rig. It has a one piece Fiberglass roof and other features to keep the water out.
|
AstroRig57
near Tehachapi, CA
Senior Member
Joined: 01/15/2009
View Profile
|
rcase13 wrote:
No problem I guess I just assumed that there would be studs every 16" like a house. When I saw the huge space between the aluminum frames I thought there would be wood studs to make up the difference. In my mind I can't see how an aluminum frame with huge spacing could support all the cabinets etc. in a crash. My son and wife will spend time in the back while on the road and I just want to be clear in my mind how these things are constructed. Asking the dealer these questions did not give me warm and fuzzies... They told me they were safe and I would never have wood rot. I wanted to get an unbiased view.
Again I am a newbie so bare with me. I'm doing my best to research and not ask so many stupid questions.
In many cases, cabinets and appliances are attached THROUGH the laminate walls to steel plates which, in turn, are attached to the aluminum tubing. This "feature" has been used as a selling point by many manufacturers.
* This post was
edited 08/24/09 11:43pm by AstroRig57 *
2005 31' Coachmen Freelander 3150SS, Stargazer II - Mobile Astronomy Unit
Do you remember when the sky was dark, and the stars were bright?
The International Dark-Sky Association
American by birth...Scottish by the Grace Of God.
|
rcase13
Charlotte
New Member
Joined: 07/28/2009
View Profile
Offline
|
AstroRig57 wrote:rcase13 wrote:
No problem I guess I just assumed that there would be studs every 16" like a house. When I saw the huge space between the aluminum frames I thought there would be wood studs to make up the difference. In my mind I can't see how an aluminum frame with huge spacing could support all the cabinets etc. in a crash. My son and wife will spend time in the back while on the road and I just want to be clear in my mind how these things are constructed. Asking the dealer these questions did not give me warm and fuzzies... They told me they were safe and I would never have wood rot. I wanted to get an unbiased view.
Again I am a newbie so bare with me. I'm doing my best to research and not ask so many stupid questions.
In many cases, cabinets and appliances are attached THROUGH the laminate walls to steel plates which, in turn, are attached to the aluminum tubing. This "feature" has been used as a selling point by many manufacturers.
I wonder what companies do this? I'll have to do some more research. I feel much better with this type of construction.
|
ron.dittmer
We Danced & Won, Check Out My Website
Senior Member
Joined: 02/26/2007
View Profile
Offline
|
I think we are describing the same or similar construction methods using different terminology.
I was trying to describe the methods used for our Phoenix Cruiser motor home. Phoenix USA describes their construction as follows.
- Aerodynamic Body Styling with Curved Walls
- Smooth Vacu-Bond Laminated Gel-Coat Fiberglass Exterior
- 2-1/8" Thick Floor, Tubular Steel Construction
- Strong, Long Lasting 1/4" Plastic Fluted Sheet Underbelly
- Rubber Pucks Between Floor & Frame for Smoother Ride and Road Noise Reduction
- Moisture Proof Plywood as Flooring Sub-Base
- 1-1/2" Thick Wall, Aluminum Cage Construction
- Metal Framing Around All Openings (Windows, Doors, etc)
- Block Foam Insulation in Roof, Floors, and Sidewalls.
We Danced The Rumba.
Click on the link in my profile
to see a video & explanation below it.
|
rcase13
Charlotte
New Member
Joined: 07/28/2009
View Profile
Offline
|
ron.dittmer wrote:I think we are describing the same or similar construction methods using different terminology.
I was trying to describe the methods used for our Phoenix Cruiser motor home. Phoenix USA describes their construction as follows.
- Aerodynamic Body Styling with Curved Walls
- Smooth Vacu-Bond Laminated Gel-Coat Fiberglass Exterior
- 2-1/8" Thick Floor, Tubular Steel Construction
- Strong, Long Lasting 1/4" Plastic Fluted Sheet Underbelly
- Rubber Pucks Between Floor & Frame for Smoother Ride and Road Noise Reduction
- Moisture Proof Plywood as Flooring Sub-Base
- 1-1/2" Thick Wall, Aluminum Cage Construction
- Metal Framing Around All Openings (Windows, Doors, etc)
- Block Foam Insulation in Roof, Floors, and Sidewalls.
How are the cabinets attached to the wall? I don't see this listed on the website. I was impressed with the video showing the build. I see at least one model that had a floor plan we liked. The 2700 was almost perfect for us. The wife wants a walk around queen. The only bummer was no upper bunk for my 7 year old. He REALLY wants that. It's like a tree house for him! 
Dad just wants safety...
|
|
|
|
