Tip Top Tier Drop

Design & Construction of anything that's not a teardrop e.g. Grasshoppers or Sunspots

Tip Top Tier Drop weight measured

Postby WizardOfOdds » Mon Jul 18, 2016 8:25 pm

I finally got around to weighing the Tip Top Tier Drop (Pisa Ed) at the local landfill. The result: 550 lbs (+/- 10 lbs; the scale had a granularity of 20# and vacillated a little). This is just the empty trailer (includes tonge jack but no mattress or any equipment), and a little less than I anticipated. I expected the Pisa Edition to weight a few pounds less than the original, but it now looks like my original estimate was a bit heavy. (That estimate was made by adding up the volumes of various wood parts and applying an estimated density. It gave an estimate of 570# plus 30# allowance for metal hardware for a total of 600#.)

I am happy with the results because it falls within my desired envelope for towing with a 4 cylinder TV and I doubt I can bring the total down much without major concessions.
WizardOfOdds: Chalet shaped rag roof clam shell TIER drop for 4 cylinder tow
Tip Top Tier Drop thread http://www.tnttt.com/viewtopic.php?f=5&t=56232
Unusual Designs thread http://www.tnttt.com/viewtopic.php?f=5&t=64495
Tale of 2 Trailers thread http://www.tnttt.com/viewtopic.php?f=35&t=61451
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Re: Tip Top Tier Drop

Postby OP827 » Thu Aug 18, 2016 9:10 pm

Thanks for sharing. I really like the simplicity and yet great functionality of your design. I have read your thread in full now and noticed that back in 2014 you were looking for a free CAD program which can be used for modeling moving parts. I had the same need and found that in sketchup I could use move and copy tools in combination with layers to create copies of moving parts to view them in separate layers. I also had difficulties learning sketchup until I found (in my opinion) some very good tutorials to learn how to use sketchup here: http://jayscustomcreations.com/sketchup/
Using keyboard shortcuts saves me a lot of time and makes 3D modeling much quicker.

I wish you and yours all the best. Hope to see more of your creative thinking.
My foldable foam trailer build: http://www.tnttt.com/viewtopic.php?f=50&t=61344
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Re: Tip Top Tier Drop

Postby WizardOfOdds » Fri Aug 19, 2016 9:22 pm

OP827 wrote
Thanks for sharing. I really like the simplicity and yet great functionality of your design. I have read your thread in full now and noticed that back in 2014 you were looking for a free CAD program which can be used for modeling moving parts. I had the same need and found that in sketchup I could use move and copy tools in combination with layers to create copies of moving parts to view them in separate layers. I also had difficulties learning sketchup until I found (in my opinion) some very good tutorials to learn how to use sketchup here: http://jayscustomcreations.com/sketchup/
Using keyboard shortcuts saves me a lot of time and makes 3D modeling much quicker.

Thanks for the kind words and the tip on Sketchup. The reason I wanted a CAD that does moving parts is to help in dealing with an issure I call "lock down", a situation in which the trailer can be in either of two configurations (open or closed state) but can not move from one to the other because some parts limit movement before the other state can be reached. I call it lock down because I first encountered it with a design in which you could not lift the upper portion because as you lifted the back end, another part of the top needed to first rotate slightly downward (before reversing and raising upward). This is only a problem with multiple pivot designs. One fix was to accommodate the small downward movement with cutouts in the base, and I recall writing a program which displayed all the moving links for various degrees of opening. I also recall there was a freeware program for doing stick figure cartoon characters with multiple pivots which calculated and drew the new locations of connected links as you move one of the joints, but I never got around to investigating it much.

Right now I'm busy with other things, but I'll try to see if I can draw up a stick figure to illustrate the problem. I'll also give Sketchup a try after looking over your tutorial links. Thanks for the tip!


Edit 6/13/2018: I did put together an animated gif to illustrate this over a year ago, but it would not animate when uploaded to my album. The second try (months later) had the same problem. My 3rd try (tonight with a less complex gif as a test) suffered the same fate. I plan to add it here as soon as I can resolve why the post does not animate.
Last edited by WizardOfOdds on Wed Jun 13, 2018 10:30 pm, edited 1 time in total.
WizardOfOdds: Chalet shaped rag roof clam shell TIER drop for 4 cylinder tow
Tip Top Tier Drop thread http://www.tnttt.com/viewtopic.php?f=5&t=56232
Unusual Designs thread http://www.tnttt.com/viewtopic.php?f=5&t=64495
Tale of 2 Trailers thread http://www.tnttt.com/viewtopic.php?f=35&t=61451
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Clam Shell Comments

Postby WizardOfOdds » Sat Jun 09, 2018 10:57 pm

I just added the comments below to a thread in the "Foamie" forum. I am adding a copy here because it relates to the overall history behind the Tip Top Tier Drop...

As this will essential be two open “halves”, only attached by a piano hinge at the back and lock down clamps at the front (when traveling); will foam give enough rigidity to keep it from flexing, or do you think I’d need a stick frame (say 2x2) with XPS?


For what it’s worth, here are my two cents:

I don’t worry about the closed state, nor do I consider the key question to be rigidity of the erected configuration (top raised and latched)....

Yes, it is true that a opened pop up does not have the rigidity of the classic tear drop or even that of a simple fixed box trailer, even though the two halves are latched together. This is especially true with a telescoping top because (unlike the base), the top can not have cross corner reinforcement (it has to nest over the bottom). However, my chief concern in designing the Tip Top Tier Drop was always the stability of the top during erection before it is latched to the bottom. Diagonal flexing was my major worry because the top had to be manually raised (by an elderly weakling with no assistance) and that meant holding it in the raised position with one hand while latching with the other. Finding the right balance between stability (rigidity), cost and weight was my aim and that drove me to experimenting with very marginal construction to see what I could achieve.

Manual lifting also put a limit on open height since I had to be able to reach a height clearing the latches. I knew this would be problem with camp sites that “rolled off” in the back, but what I under estimated was how often that would be the case. In fact, many camp site pads have a log back stop (which often ends up under the rear of the trailer) and a steep drop-off beyond it, creating quite a step down off the back of the trailer. We keep a stool handy for such situations, but sometimes that stool is needed just to raise the top.

Your diagrams show the reverse, the top is hinged at the rear, which has an obvious advantage in such a case. Also, your flip-up end and side walls should reduce lift weight, but there are set up exposure advantages with telescoping designs. In any case, I find clam shell designs well matched to manual erection constraints.
WizardOfOdds: Chalet shaped rag roof clam shell TIER drop for 4 cylinder tow
Tip Top Tier Drop thread http://www.tnttt.com/viewtopic.php?f=5&t=56232
Unusual Designs thread http://www.tnttt.com/viewtopic.php?f=5&t=64495
Tale of 2 Trailers thread http://www.tnttt.com/viewtopic.php?f=35&t=61451
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