Hey Guys, we’ve been trying to hard to figure it out, Simple is better.
(http://i1234.photobucket.com/albums/ff403/dave2-8-0/WT-55.jpg)
For real. I spent some time making a cardboard mock-up roof, Thanks Jon, John, Bruce, Gary et all… I agree with ya Bruce, it was to steep, so in my cardboard mock-up I dropped the pitch, and used some of Johns math, and came up with this.
(http://i1234.photobucket.com/albums/ff403/dave2-8-0/WT-58.jpg)
Its not exactly right, but closer then I’ve had . Gary offered a computer generated plan, and I think that will clear up all of the issues.
(http://i1234.photobucket.com/albums/ff403/dave2-8-0/WT-56.jpg)
Hows this look to you guys?. I’m thinking the height is about right. Would it look better with more overhang? @Randy, I tried to use your chop saw technique but I couldn’t cut a 17 inch piece at those angles. I thought that I might be able to cut it in half, but the angles got goofy and I gave up, Thanks tho.
It depends on whether you like that octagonal shape or not, Dave. It’s what I was thinking about when I posted yesterday. If you want the circular look that Gary was talking about, then his computer app would have been simpler after all. Until Gary’s post yesterday I had never heard of a SPLINE - but I looked it up and I understand the function - I’m not just a pretty face, Hah ha! I slept with his thoughts last night and I got it firmly in my mind. As a matter of fact I have a water tank project in mind myself and I may lean on Gary to produce my lines for me if he’s willing - and if I can get it from him as a GIF file, as I don’t think I can open vectors on this computer anymore. Anyway, my string and my compass and my divider won’t do the job, and Gary knows this - it’ll only produce curves which we don’t want here, where a ccylinder intersects a sloping plane. A spacer around the tank, as I suggested, would work, but it’s awkward, as you couldn’t easily draw the line on the underside of the roof or cut it afterwards. But you easily cut the roof’s perimeter from the top, even now, after assembly. Now the roof is assembled, if you want a circle as seen from above as Gary suggested you might, I think my little sketch below may be the best way to go, and it may have been the method those old guys used. They would have had a kind of ‘three dimensional’ trammel rotating around center at the roof peak, which held a pencil or a chalk marker vertically over the desired perimeter of the roof. They would keep the trammel level and the marker vertical as it rotated around. The marker would ride freely up and down the slopes across those triangles over the course of its travel around. The resulting line would be the SPLINE that Gary is talking about. Do you agree, Gary? OK so here’s the sketch:
(http://freightsheds.largescalecentral.com/users/choochoo_chaboogie/_forumfiles/trammel.jpg)
Then you’d cut around with a jigsaw.
Oh, that’s just a mockup. You’re golden! Ask Gary for his assistance now, if you want that circle. As for the roof pitch, I’d go with the engineer’s maxim: “If it looks right, it is right.” The slope is more a matter of your own personal taste than anything, dont’cha think?. Make is so’s YOU like it!
That looks a lot better. I MIGHT try another mockup that has a bit more overhang; there’s no telling until you actually see it, but it does look pretty good now.
How thick will the roof pieces be? Be prepared to bevel cut the edges - and that will not be easy with that angle!
Good morning guys. I want to thank Dave for his response to my e-mail yesterday regarding his roof. John that "compass you sketched out would work great, but with the cad system, I can actually make the roof into a “surface” and project the curve onto that surface (from any angle, depending on the slope) and you automatically get a spline. ALL of this depends on whether the curve is projected to the roof in relation to the view of sight OR natyral to the roof surface. Sounds a lot more complicated than it is, believe me.
I have a doctor appointment this morning and as soon as I get home, I will contact Dave and get the exact figures for his roof. No problem.
Perfect, Gary!
Dave, I found this site where Dave Bodnar built a water tower for his garden railroad. He did an interesting spider like rafter system for the roof.
(http://www.davebodnar.com/railway/watertower/tower3_small.JPG)
(http://www.davebodnar.com/railway/watertower/tower1_small.JPG)
(http://www.davebodnar.com/railway/watertower/roofsupports_small.JPG)
Note that the rise/run for the roof is dramatically less than you have chosen, much more pleasing to my eye. If I had to guess, I would say that the rise/run was near 3/12
(http://www.davebodnar.com/railway/watertower/withroof1_small.JPG)
The plans he used are here. Even at this late date, you might find something useful here. Here are some pics from different prototypes…
(http://img.groundspeak.com/waymarking/large/bb94184c-3b8f-48d5-8640-fd47c9f4796f.JPG)
Los Pinos, NM.
(http://www.gngoat.org/Gnr24.jpg)
Great Northern Railway, Wenatchee, WA. Icing the reefers. I grew up about 3 miles from here. My daughter can see this location from the school she teaches at.
Pitch still looks a little too steep. Overhang looks about right.
Ralph
That looks nice. I need something like that to fill my live steamers up.
OK guys. I think that Gary’s computer drawing will solve the technical end of the roof line. I too agree that the height (pitch) is to high, mostly for the visual look. I have been referencing the C&NW plans from the start. The pitch on that one is or appears to be much shallower then the D&RG photo that Steve posted of the Los Pinos tank, but the C&NW tank is a 24 ft. tank, and the D&RG I believe is 15 ft. Short and fat verses tall and skinny like the ones in the background of the Iceing shot.
I really do want the input on this guys,
Give me a voice on lowering : A lot, A little, Some.
Overhang compared to mock up: More, Less, Same
Looking down on the top, on the ends of the triangles / eves: Hexagonal, or Round
My goal is for this coming weekend or sooner, if work doesn’t get in the way.
My 2 cents worth Dave…a roof pitch of about 4-5 in 12, Hex roof and about a 12" scale overhang for the eaves at the middle of the straight sections of the eaves. FWIW.
I like a fairly generous overhang. and stingy ones sort of bother me… I don’t have opinions about the pitch or the octagon/round options.
I prefer the shallower rise/run, say 3-4/12, but that is just me.
If the area expected a lot of snow, I suppose they opted for a steeper rise/run. The larger, taller tanks seemed to have a steeper rise/run. Dunno why.
I like them shallower, My 2 cents worth.
Got the CAD drawings from Gary Armitstead this pm. WOW guys, this is really high tech drawing in 3D. For those of you that don’t recognize it this is State of the Art stuff here. Gary took my chicken scratches ( no offense Roster) and turned them into 21st century stuff.
(http://i1234.photobucket.com/albums/ff403/dave2-8-0/finishroofsideview05042012.jpg)
(http://i1234.photobucket.com/albums/ff403/dave2-8-0/finishroofisoview05042012.jpg)
(http://i1234.photobucket.com/albums/ff403/dave2-8-0/roofsurfaceshaded05032012.jpg)
Now if only I had a CAD driven table saw. I know that I’m not going to be able to cut to Garys ± .001 tolerances. Not with my miter gage.
(http://i1234.photobucket.com/albums/ff403/dave2-8-0/finishroofscallopwall05042012.jpg)
(http://i1234.photobucket.com/albums/ff403/dave2-8-0/finishroofundersideeave.jpg)
(http://i1234.photobucket.com/albums/ff403/dave2-8-0/completedroof05042012.jpg)
Gary also sent a set of dimensioned drawings with all the call outs, and I haven’t been able to convert to .JPGs yet. Looks like this weekend will be busy. Thanks Again Gary for all the time and work put into helping me get this right.
Two thumbs up for Gary 
Ralph
Happy to help Dave. Any time. The nice part about doing this stuff, is that it keeps an old retired brain active!
Pretty impressive work, Gary! Sure beats my old trial and error ways. 
And, it has a pleasing rise/run! :lol:
BZ, Gary.
Very impressive graphics, Gary!
So, when all’s said and done, Dave, are we going circular or octagonal here?
That’s what I’m waiting to find out!
I’ve been rained out of my garden for the past two weeks - finally some clear weather & a chance of railroading, or at least some Spring cleaning-up out there.
Here’s to a productive weekend, Dave - actually, for all of us.
Cheers!