Fiberglass Egg Shapes - Fiberglass RV
Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×


Reply
 
Thread Tools Search this Thread Display Modes
 
Old 09-10-2013, 04:50 PM   #1
Junior Member
 
Name: Troy
Trailer: Shopping
Nova Scotia
Posts: 8
Fiberglass Egg Shapes

I was curious, looking at the differing shapes of the RV's -- some "Boleresque" with softer lines and rounded corners and others, like the Beachcomber and Trillium Jubilee, with a squared-off shape.

Other than esthetiques, are there any functional differences between those two predominant styles? I've heard the squarer design has a feeling of greater interior space, but I am also wondering about "nuts & bolts" differences. For example, (from my research on this awesome site) a common problem is door sag -- is there any benefit to the door style in say a Trillium Jubilee vs. a regular 1300/4500/5500 Trill? What about replacing windows ... modifications ...?

Anyone with practical experience that would care to comment? Thanks.

troy
Dreamcatcher is offline   Reply With Quote
Old 09-10-2013, 06:37 PM   #2
Senior Member
 
rabbit's Avatar
 
Name: Jack
Trailer: '98 BURRO 17WB
Delaware
Posts: 2,548
You no doubt have heard of the carney trick involving the difficulty of breaking an egg by pushing on the ends with thumb and forefinger. The ends are very strong-basically arches rotated thru 360 degrees. Our camper eggs do not quite copy the geometry of the chick packaging ovoid but they do share surfaces of compound curvature, the corner radii in cases where these curve in plan or elevation and in the more egg like [Boler], large wall and end facets are also compound curves which resist deflection.

The Trillium/Amerigo/Bigfoot style uses corners of lesser radius and frequently no curvature in plan or elevation views. The sides and ends approximate true planes rather then compounds. I believe they are less resistant to deflection than is the more egg-like Boler/Scamp/Casita/Burro style.

It is clear to me that the designers who tended to the egg shape rather than radiused rectilinearity understood very well the benefits of curves as sectional stiffeners. These are usually the trailers that also employ the trolley roof section--an iteration of the wall to top and wall to end radius. Most of the trailers that tend to the rectilinear "trough" styling do not use the trolley top. Bigfoot is a case where internal framing (transverse battens or carlins) was employed to stiffen rooves against deflection.

I prefer the self-stiffening of the more egglike eggs. However, a door that will seal and seal reliably requires a rigid door case. A door case, curved or planar, protrudes inward or outward or both. Frequently, an adjacent interior partition or bulkhead acts as a stiffener at one side of door but is not all the engineering required. I believe a time and wrack-proof door opening is problematical in both classes of design. The flat door is much easier and cheaper to build and repair but many will say the eggsthetics suffer as a result.

jack
rabbit is offline   Reply With Quote
Old 09-10-2013, 07:33 PM   #3
Junior Member
 
Name: Troy
Trailer: Shopping
Nova Scotia
Posts: 8
Wow. Excellent, extremely thorough analysis. I had no idea the "protective" egg properties translated to that scale -- I honestly thought the design idea was moreso related to wind resistance and esthetics. Thanks. Another layer to consider.
Dreamcatcher is offline   Reply With Quote
Old 09-10-2013, 07:47 PM   #4
Senior Member
 
rabbit's Avatar
 
Name: Jack
Trailer: '98 BURRO 17WB
Delaware
Posts: 2,548
As above so below.

jack
rabbit is offline   Reply With Quote
Old 09-10-2013, 09:08 PM   #5
Commercial Member
 
Name: Mike
Trailer: Boler13/trillium4500/buro13
Ontario
Posts: 1,138
Quote:
Originally Posted by rabbit View Post
You no doubt have heard of the carney trick involving the difficulty of breaking an egg by pushing on the ends with thumb and forefinger. The ends are very strong-basically arches rotated thru 360 degrees. Our camper eggs do not quite copy the geometry of the chick packaging ovoid but they do share surfaces of compound curvature, the corner radii in cases where these curve in plan or elevation and in the more egg like [Boler], large wall and end facets are also compound curves which resist deflection.

The Trillium/Amerigo/Bigfoot style uses corners of lesser radius and frequently no curvature in plan or elevation views. The sides and ends approximate true planes rather then compounds. I believe they are less resistant to deflection than is the more egg-like Boler/Scamp/Casita/Burro style.

It is clear to me that the designers who tended to the egg shape rather than radiused rectilinearity understood very well the benefits of curves as sectional stiffeners. These are usually the trailers that also employ the trolley roof section--an iteration of the wall to top and wall to end radius. Most of the trailers that tend to the rectilinear "trough" styling do not use the trolley top. Bigfoot is a case where internal framing (transverse battens or carlins) was employed to stiffen rooves against deflection.

I prefer the self-stiffening of the more egglike eggs. However, a door that will seal and seal reliably requires a rigid door case. A door case, curved or planar, protrudes inward or outward or both. Frequently, an adjacent interior partition or bulkhead acts as a stiffener at one side of door but is not all the engineering required. I believe a time and wrack-proof door opening is problematical in both classes of design. The flat door is much easier and cheaper to build and repair but many will say the eggsthetics suffer as a result.

jack
That's exactly what I was going to say lol
Mikmay is offline   Reply With Quote
Old 09-10-2013, 09:38 PM   #6
Senior Member
 
Donna D.'s Avatar
 
Trailer: 1988 16 ft Scamp Deluxe
Posts: 25,697
And here I thought the egg-shaped trailer was built that way to make it cute!
__________________
Donna D.
Ten Forward - 2014 Escape 5.0 TA
Double Yolk - 1988 16' Scamp Deluxe
Donna D. is offline   Reply With Quote
Old 09-10-2013, 11:33 PM   #7
Senior Member
 
Brian B-P's Avatar
 
Trailer: Boler (B1700RGH) 1979
Posts: 5,002
Quote:
Originally Posted by Dreamcatcher View Post
What about replacing windows ...
Regardless of the shape of the rest of the trailer, almost all window areas are designed to be flat, so special windows are not required, and the shape does not affect the installation. Similarly, large flat areas on the sides accommodate refrigerator vents and other fittings.

Notable exceptions are the front windows and in some cases rear windows of the Boler 1300 and various trailers (such as Scamps) derived from it. These windows are just flat sheets of acrylic held in the opening by a rubber gasket; they are not formed to curve of the body, they are just forced into place and will spring back to flat if removed (at least initially).
__________________
1979 Boler B1700RGH, pulled by 2004 Toyota Sienna LE 2WD
Information is good. Lack of information is not so good, but misinformation is much worse. Check facts, and apply common sense liberally.
STATUS: No longer active in forum.
Brian B-P is offline   Reply With Quote
Old 09-10-2013, 11:43 PM   #8
Senior Member
 
Name: Daniel A.
Trailer: Bigfoot 17.0 1991 dlx
British Columbia
Posts: 741
Registry
The functional differences between build molds is where the seam is.
Some have an upper & lower half shell and others the seam is from the middle. Given the risk of acceptance and cost of molds there is not much incentive for a manufacture to stray from the norm.

I do believe that a Scamp or Casita would provide better gas milage with the rounder shape.
I think the Bigfoot with all the additional framing provides a stronger structure same for Trillium .
Daniel A. is offline   Reply With Quote
Old 09-11-2013, 07:00 AM   #9
Raz
Senior Member
 
Raz's Avatar
 
Trailer: Trillium 2010
Posts: 5,185
Quote:
Originally Posted by rabbit

The Trillium/Amerigo/Bigfoot style uses corners of lesser radius and frequently no curvature in plan or elevation views. The sides and ends approximate true planes rather then compounds. I believe they are less resistant to deflection than is the more egg-like Boler/Scamp/Casita/Burro style.

It is clear to me that the designers who tended to the egg shape rather than radiused rectilinearity understood very well the benefits of curves as sectional stiffeners. These are usually the trailers that also employ the trolley roof section--an iteration of the wall to top and wall to end radius. Most of the trailers that tend to the rectilinear "trough" styling do not use the trolley top. Bigfoot is a case where internal framing (transverse battens or carlins) was employed to stiffen rooves against deflection.



jack
What's a "trolley roof"? Raz
Attached Thumbnails
image-580878960.jpg   image-3019655545.jpg  

Attached Images
  
Raz is offline   Reply With Quote
Old 09-11-2013, 07:32 AM   #10
Senior Member
 
rabbit's Avatar
 
Name: Jack
Trailer: '98 BURRO 17WB
Delaware
Posts: 2,548
Raz, the first foto; is that Lum's Pond in DE? Looking at your Trill, I'd say it has a raised central roof area. Is that the case? Scamp does not have a such a roof but Casita, Burro, UHaul do. Not certain about EggCamper.

It may be that not every urban trolley car had a roof with a raised central section but many did, hence the derivation trolley roof or trolley car roof. On most of these trailers, the demand for full standing height in the central corridor and only there may have been a consideration as equally important as roof stiffening in the genesis if this feature. Oddly, the ParkLiner has what is referred to as a "reverse trolley" or pontoon roof showing a raised longitudinal area at each side of trailer. This feature is admired by those for whom overhead storage is paramount.

jack
rabbit is offline   Reply With Quote
Old 09-11-2013, 07:37 AM   #11
Senior Member
 
cpaharley2008's Avatar
 
Name: jim
Trailer: 2022 Escape19 pulled by 2014 Dodge Ram Hemi Sport
Pennsylvania
Posts: 6,710
Registry
Parkliner has an anti trolley roof without windows, flat on top. If you are old enough to remember riding in streetcars and some railroad cars, the roof was elevated but flattened and had windows for ventilation which due to them being under the roof kept some rain out. This also made the roof stronger than it would have been without. See here Light Rail Products: Railroad Roof Modification
Attached Images
 
__________________
Jim
Never in doubt, often wrong
cpaharley2008 is offline   Reply With Quote
Old 09-11-2013, 07:46 AM   #12
Senior Member
 
rabbit's Avatar
 
Name: Jack
Trailer: '98 BURRO 17WB
Delaware
Posts: 2,548
None of our trailers have the clerestory fenestration of a trolley. Obviously, ventilation was not the reason for raising the roof.

jack
rabbit is offline   Reply With Quote
Old 09-11-2013, 08:01 AM   #13
Senior Member
 
honda03842's Avatar
 
Name: Norm and Ginny
Trailer: Scamp 16
Florida
Posts: 7,517
"Scamp does not have a such a roof but Casita, Burro, UHaul do."

Jack,
Unless I've mis-read your post, Scamp does have a trolley roof. Beyond providing central aisle headroom, it stiffens the roof, much like rippled truck beds.
__________________
Norm and Ginny

2014 Honda Odyssey
1991 Scamp 16
honda03842 is offline   Reply With Quote
Old 09-11-2013, 08:02 AM   #14
Raz
Senior Member
 
Raz's Avatar
 
Trailer: Trillium 2010
Posts: 5,185
Quote:
Originally Posted by rabbit View Post
Raz, the first foto; is that Lum's Pond in DE? Looking at your Trill, I'd say it has a raised central roof area. Is that the case? Scamp does not have a such a roof but Casita, Burro, UHaul do. Not certain about EggCamper.

It may be that not every urban trolley car had a roof with a raised central section but many did, hence the derivation trolley roof or trolley car roof. On most of these trailers, the demand for full standing height in the central corridor and only there may have been a consideration as equally important as roof stiffening in the genesis if this feature. Oddly, the ParkLiner has what is referred to as a "reverse trolley" or pontoon roof showing a raised longitudinal area at each side of trailer. This feature is admired by those for whom overhead storage is paramount.

jack
Lums? Yup

Perhaps not a good picture but if you look closer at the Scamp roof.
Raz is offline   Reply With Quote
Old 09-11-2013, 08:06 AM   #15
Senior Member
 
Roy in TO's Avatar
 
Trailer: 1972 Boler American and 1979 Trillium 4500
Posts: 5,137
Quote:
Originally Posted by rabbit View Post
You no doubt have heard of the carney trick involving the difficulty of breaking an egg by pushing on the ends with thumb and forefinger.
I feel this applies in general theory when comparing our eggs to stick builts. Then we have to factor in that a hole of approximately 20% is cut into the circumferential structure for a door. In some models more for a floor. Where those two points meet is a week area oft cited as being a major factor in door sag.

The structural integrety is improved with the addition of various countours in the surface. For example the "trolley roof" not only allows for increased height, it increases structural integrity and prevents the roof from flapping as we drive down the road.

Other factors to consider are how the various components are joined. Are they riveted together? Are they screwed to wood or wood products laminated to the fiberglass? Are they glassed together at structural features?

One has to look deeper than the outer skin to understand the differences.
Roy in TO is offline   Reply With Quote
Old 09-11-2013, 08:33 AM   #16
Senior Member
 
rabbit's Avatar
 
Name: Jack
Trailer: '98 BURRO 17WB
Delaware
Posts: 2,548
Thanks for the correction, Norm. The raised section is very hard to detect, at least by me. Is it the case that the Scamp roof displays more of a ripple or corrugation, as in your truck bed analogy, rather than a deep step?

jack
rabbit is offline   Reply With Quote
Old 09-11-2013, 08:50 AM   #17
Senior Member
 
rabbit's Avatar
 
Name: Jack
Trailer: '98 BURRO 17WB
Delaware
Posts: 2,548
Brian, there is a recent thread by Cathy Futrell, subject being her difficulty getting rigid window frames to fay with the vertical wall curvature of her Love Bug. One correspondent concluded that the wall curvature in the window area was likely the result of outward sag due to roof weight rather than mold-determined.

jack
rabbit is offline   Reply With Quote
Old 09-11-2013, 09:02 AM   #18
Senior Member
 
Roy in TO's Avatar
 
Trailer: 1972 Boler American and 1979 Trillium 4500
Posts: 5,137
Quote:
Originally Posted by rabbit View Post
Think it may have been Roy?
Are you trying to egg me on?
Roy in TO is offline   Reply With Quote
Old 09-11-2013, 09:21 AM   #19
Senior Member
 
honda03842's Avatar
 
Name: Norm and Ginny
Trailer: Scamp 16
Florida
Posts: 7,517
Jack,

From the front or rear it's difficult to detect the Scamp's trolly because it blends down to the curvature of the trailer. From the side it's clear that it's 3 or four inches. The top of the trolly section is also curved like most Scamp surfaces though not too much for a flexible solar panel.
__________________
Norm and Ginny

2014 Honda Odyssey
1991 Scamp 16
honda03842 is offline   Reply With Quote
Old 09-11-2013, 09:32 AM   #20
Senior Member
 
Bob Miller's Avatar
 
Trailer: Class A Motorhome
Posts: 7,912
Hmmmmm, it sounds like we are discussing the design of the next spacecraft to Mars..... where a single fitting can cost more than a new Scamp.

It appears that the sagging door issue is more associated with certain mfgs. than shape. Bigfoot, for example, built a 13' egg, but used a square edge flat door to take care of that issue.

And remember that Boler begat Scamp and the dozens of other followers just knocked off from those designs, hence the popularity of the shape.

I think that personal preference and use trumps any MPG differences that shape might imbue.

For a given envelope size the square trailer will have more useful storage and sleeping space. Those that get relegated to the back area of the dinette/bed (me)or the front bunks of most Eggs will agreed I am sure.

As far as sturdiness, my 1973 Hunter is as old as 99% of the eggs out there and it's square shape is as sturdy and rigid as it was 40 years ago.

Again, go with what you like, and ferget the engineering considerations.....



Bob Miller is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Shelter Shapes Next to Trailers D Davis Modifications, Alterations and Updates 43 06-20-2013 03:28 PM
Are trailer shapes patented? Ken C General Chat 7 12-31-2012 02:42 PM
What are these two fiberglass egg's? Robin G General Chat 27 12-02-2012 05:01 PM
Egg Shapes, one more roomy than another? melissab General Chat 20 08-21-2010 07:38 PM
New Fiberglass Egg On Market Legacy Posts General Chat 36 05-29-2003 10:29 PM

» Upcoming Events
No events scheduled in
the next 465 days.
» Featured Campgrounds

Reviews provided by


All times are GMT -6. The time now is 07:07 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.