The hangar is 24' deep and 35' 4" wide. The outside walls are framed 8' high from the lower frame to the top, and then the roof beams set on the top plate. The side and back walls are built using 4' X 8' sheets of 7/16" waferboard, (chipboard, strandboard, osb, whatever. It is more waterproof than plywood) so everything is in multiples of 4' X 8'. The side walls are made in two 8' high by 12' long sections, fitted in between pressure treated 4" X 4"s. Each section uses 3 sheets of wafer board.
The pictures above are the side wall, it has one 4" X 4" at each end and one in the middle, each sunk 2' into the ground, and the two sections are nailed between them, then another 2" X 4" plate is nailed length wise along the top, over the top of the 4" X 4", to help tie everything together. Notice that each section has a vertical 2" X 4" every 2' on center, to give something to nail the wafer board panels to. The wafer board panels should completely overlap the 4" X 4"s at either end, so each frame section is actually a bit shorter than 12' so that the overlap comes out right and you don't have gaps. (The frame is less than 12', the waferboards overlap the frame at each end and come out to 12') I have eight 4" X 4"s in all, three on each end, and two in the back side. The two 4" X 4"s on the back side wall will line up with the trusses, and be tied to them. Do not pour the cement around the 4" X 4"s until the hangar walls are finished, & everything is nailed together and squared up. In the above pictures, since the ground falls away, there is an added "skirt" below the bottom of the frame.
While you are pouring the concrete for the
4" X 4"s, go ahead and pour two footers for the trusses
to sit on, because they are the heart of the hangar. While you
are waiting for the concrete to cure, you can be making the trusses
and cutting the roof beams to length and fit. The hangar width
was determined by the length of the roofing panels I used. 18'
was the longest I could get, so the rear wall was sized to allow
the panels to almost reach the peak of the roof, and still stick
out 2" over the eaves. This gave me two rear outside wall
sections 137" wide and a rear center section of wall 139"
wide. I cut a door in one section of the back wall, be sure not
to cut through the bottom plate of 2" X 4"s, just plan
to step over them. The peak of the roof is covered with a standard
pre-bent cap strip.
The heart of the hangar is the two cantilever
trusses, which are very simple and similar to built up wing spars,
because they sandwich sections of wafer board between 2"
X 4"s to make a very strong structure. In the drawing above
left, the door end of the truss is to the left, and the part that
goes to the back of the hangar is to the right. The bottom portion
of the truss is 24" wide and 75" tall. Resting on top
of this is the center of the truss, which is a 4' X 8' sheet,
with the lower corner triangles cut away. To cut away the rear
corner triangle: starting at the corner, measure out 3', and up
2', draw a diagonal line, and cut that triangle off. To cut off
the lower front corner triangle, Starting at the corner, measure
up 1', out 3', draw a diagonal line between the marks, and cut
that triangle off.
To make the rear end of the trusses,
cut a 4' X 8' sheet of 5/8" wafer board down the middle,
making two 2' X 8' sheets. To make the front end of the truss,
cut a 4' X 8' sheet on the diagonal, so that you have two "almost
triangles" that measure 8' on the top side, 3' on the rear
side, (the side that butts up against the middle of the truss)
and instead of coming to a point at the front side of the triangle,
you want 8" of vertical depth. Now box the whole truss in
with 2" X 4"s along the edges of both sides, just like
in the picture. Plan ahead about how you will splice the 2"
X 4"s. Think about where the stresses lie, and make the 2"
X 4"s that go up the lower leg of the truss continuous to
the top of the truss, and have them stop at the horizontal 2"
X 4"s. (Don't cut into the horizontals!) Likewise the horizontal
2" X 4"s that run out to the front, keep them as long
as possible to where they tie into the rear section. Avoid splicings
that are the same on both sides, stagger your splices.
You will use one sheet of wafer board for two
vertical legs, one sheet for both truss rears, one sheet for both
truss fronts, and two sheets for the truss centers. You will need
26 sheets of wafer board total for the hangar, plus any extra
you might need for "skirts" if you have uneven ground
like I do.
The distance from the front side of the
truss leg to the front of the hangar overhang is 11', the nose
of the MKIII comes right up to this point. (I originally built
the hangar to accomodate an Anglin J-6) I have a heavy tarp that
is attached to the inside of the upper eave, and it is tied down
with two rubber elastic cords that go to ground anchors, that
keeps the rain off the airplane nose, and the sun out of the cockpit.
The front side of the hangar is ordinary sheet metal roofing,
nailed to the forwardmost roof beam and a lower 2" X 4",
braced by a 2" X 2" extending from the lower side of
the trusses, semi-visible in the pictures.
Roof
beams are 2" X 6" from the walls to the trusses, and
2" X 4" from the trusses to the ridgeline. Then 1"
X 4"s cross wise to have something to nail the roofing metal
to. Use the sheet metal roofing of your choice, I used Strongpanel,
it cost as much as the rest of the hangar combined, but you can
walk on it and it is holding up well. Use lightweight stuff for
the front and back eaves. Put gutters along both sides. I didn't
have any for years, and now the splash around the bottom has caused
some damage.
Set your walls so that the lower plate is a
couple inches above the ground. That way when the ground gets
wet, the moisture won't collect and corrode the airplane. Leaves
will blow in under the walls sometimes, but leaves don't cause
corrosion, damp hangars do. The floor of the hangar is covered
with sheet plastic, and then used carpet. Find someone that is
re carpeting their house and office and get the sections intact
and as large as possible. The only downside to using carpet is
that the mice rip off parts of it and build nests in the lawnmower...
The
outer walls will flex at the front end unless they are triangulated
or braced. I cemented a length of steel rod into the ground about
1' out from each front corner, and ran some old flying wires from
each rod to the top corner of the adjacent wall, screwed the turnbuckles
down tight, and it is solid as a rock. The roof doesn't have a
lot of pitch, the most snow we ever get around here is about 24",
and I can clean it off faster than it comes down most of the time.
You guys up in the Great White North might need more pitch than
that, that's out of my league. But it is easy enough to make up
a couple extra brace posts to fit under the very front of the
trusses if you are expecting a real load. I do not have main doors
on my hangar, but they would not be too hard to make, either folders
or sliders.