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Thanks Charlie,
All good points.
Factors to consider in my case:
1) Would like to avoid putting any weight on the truss spanning door
opening. That pretty much rules out the horizontal doors.
2) Want entire 10' x 38'8" opening unobstructed. I went through the
trouble getting that wide an opening, so it doesn't make sense to
make it smaller by obstructing doors. And 10 feet is pretty low if
I'd ever hope to get a helicopter in there.
The link that Larry sent (http://www.hortonstackdoor.com/stackdoor_description.htm)
seems to indicate that it can be done.
I was going to go with simple cart wheels on the bottom, but will
consider the track - truck assembly.
Unlike the Horton stack door, I'm planning on extending the
tracks on either side of the opening. In other words, when fully
opened the doors would be completely to the left and right of
the door opening. Also, one could push an entire door assembly
to the side a bit to create a small opening, without getting
into accordion mode. Lot's of options.
I looked at 3' sections simply because metal siding comes in 3'
wide sections. Also, the smaller the sections, the less side
load they put on the top track and truss. But yes, more trouble
opening them. Hm, considering they don't have to hang out until
reaching the sides (concrete wall/column), I guess I could make
them 6' sections.
Lots of fun considering all the possibilities.
Still no takers on calculation of "I" for square or rectangular
steel tubing?
Finn
On 12/29/2010 12:47 PM, Charlie England wrote:
On 12/28/2010 11:46 PM, Finn Lassen wrote:
Looking to design and build hangar doors.
I kinda fancy vertical harmonica doors.
/\/\/\/\/\
The inner points carried by wheels in groove in concrete slab.
Wheels able to pivot in bottom of door frames.
Top supported by rollers in a steel U-channel, able to pivot in
top of door frames.
I figure 3 feet wide sections hinged at edges.
The thinner the better, but will have to be able to withstand
wind pressure without deforming.
10 feet tall.
>>
snipped>>
Sanity
check appreciated.
Finn
Hi Finn,
Random Thoughts:
Bottom tracks/rollers could be a maintenance nightmare, especially
in the sand down there, and the track will either fill up with
sand/dirt, or if you use a raised track, be a pain to pull a plane
over. Give it some thought.
110 mph wind survival is likely to be tough to achieve with a 2"
thick door that big. What are the odds of seeing that load, even
in FL, since you're so far from the coast? Also, my thought is
that only moderate survival strength is needed when open, since if
they are left open I'm much more concerned about hangar contents
than the doors.
Accordion doors take up space in the opening of the hangar.
Thickness isn't really a factor, if the door is hung outside the
hangar & there's a small lip at the top to shelter it.
More panels = more (expensive: hinge/roller) parts = more
complexity = more build time + more money + higher maintenance.
More panels = more time/hassle to open/close the doors.
The lazy among us just copy what's been proven to work. My
neighbor has a 4-panel vertical hinge setup (commercially produced
kit) that hangs from a track; bottom edge is pinned to the floor
when closed. Works fine, but he does have to 'pin' the outer edges
to the ground when they are open. The existing pins at the 'break
point' of each door pair (required to hold the door shut) are also
used when open. Another neighbor has a product known as 'Ultimate
Door' that's a kit of track, rollers, cable, etc. The owner
supplies wood (mostly 2x4 & 1x4 stock) & the covering of
choice. It opens like an old style one-piece garage door. the
cables lift the door at vertical the center line (only 5 feet is
cantilevered above/below the lift line) & the door is guided
by the track to open and partially retract into the hangar. Mine
(a one-piece, 30' wide design for the shop side of my hangar) is
built from 6" aluminum irrigation tubing that I bought cheap. It's
hinged at the top & has a single counterweight so it swings up
with only a ~30 lb push.
I haven't built the door for the big 40+foot opening yet. I'm
seriously considering steel 'purlins', the stuff you see spanning
between the beams of metal buildings. 6-8 inch thick purlins can
easily span 40-50 feet on 5 foot centers and take full snow/wind
loads, so I'm pretty confident that they can handle door loads.
The bi-folds and one piece top-hinged doors have simplicity on
their side, and they make a nice shaded ramp area when open if you
want to pull the plain out in the breeze while doing maintenance.
FWIW,
Charlie
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