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August 30, 2004
Here to download the Volo View Viewer.
This viewer is essential for you to be able to view the drawings
of the JayBird airplane.
All drawings, photos, and information presented on these web
pages are the sole property of Jay S. McMullan and are ©
2002. Nothing on these pages can be copied or reproduced in
any way without the written, expressed permission of Jay S.
McMullan and/or his assigness.
this series, I will show how the very beginnings of an aircraft
come into being. Before the preliminary steps can begin, the
following decisions must be made:
drawings shown below are not detailed drawings. Please download
AutoDesk's DWF Viewer and then click on
the drawing you want to see. With the DWF
Viewer, you will be able to zoom in and out on
the complete drawings to see much more detail and keep up with
the progress of the design of the JayBird aircraft.
26-27 - Studied sliding canopy design and worked
on the design of the wing spars.
The wing spar design
must be determined before the fuselage design can be completed.
Once that is done, how the fuselage and the wing are joined
must be determined. There are a couple of considerations here.
Do I want each wing panel to be able to be detached? I also
could design the airplane so that the fuselage detaches behind
the trailing edge of
the wing and the wings are permanently attached to the fuselage.
do want a tapered wing which makes designing the spars and other
things more difficult but it will also give more speed to the
airplane. The wing will have 5 degrees of dihedral
and 2 to 3 degrees of washout.
I had originally decided upon 2 degrees but I noticed that the
Falco has 3 degrees. I'll have to check into that further.
are two drawings linked below. You will have to use the Volo
Viewer from AutoDesk to be able to view them closely.
first drawing is of the fuselage structure. Some of the formers
will have to be moved and beefed up when I determine the wing
spar design. Notice that the canopy slides forward to open.
This may change later.
second drawing is the beginning of the wing
spar. You will also see the airfoil
for the root and tip
of the wing.
images are © 2002 by Jay S. McMullan
on the Image to view with Volo View
1 - Fuselage Construction - August 27, 2002
2 - Wing Spar and Wing Rib Construction - August 27, 2002
26-27 - I have been working on the spar
design for the airplane and building 2 degrees of washout
into the wing. I want to carry the fuel in the wing and I think
I have found a way to carry some of it there. I may still end
up carrying some fuel in the fuselage which I drastically don't
want to do for two reasons: 1. It just isn't safe. If the fuel
is in front of the pilot and passeger, it can be thrown all
over them if there is an accident. Even if there is a leak in
the tank, it can end up in the fuselage. 2. The wing
spar won't have to carry the extra weight of the
fuel if it is carried in the wing. Fuel weighs in at 6# per
noticed that the Falco uses 3 degrees of washout
in its wing but most other planes I have looked into have 2
degrees. After rotating all of the ribs,
I think I will stay with 2 degrees. After talking to the author
of one of the books I use on aerodynamics, it seems that it
is pretty hard to precisely determine what the washout should
be. There are just too many factors to be calculated. So, I
am sticking with the 2 degrees. Use the VoloViewer and you can
see the wing ribs combined to show the degrees of washout.
3 - Wing Construction - August 28 - Sept 2, 2002
4 - Fuselage Construction - August 28 - Sept 2, 2002
19, 20 - With the wing having 2 degrees of washout,
I drew the ribs. One view shows the ribs
as they would appear from the side of the airplane, the other
with the ribs stacked
one on top of another, aligned at their centers. The stacked
view will give you a greater understanding of washout
or "wing twist".
Now comes the tedious task of measuring and drawing the wing
spars, leading edge,
trailing edge, flaps
and ailerons. All of
these tasks are very slow but will pay off in the long run when
everything fits perfectly.
drawing above, shows the different parts of a wing made with
plywood wing ribs.
The wing's spars will
be constructed from clear vertical grain Douglas fir. The next
thing I have to do is scale each wing
rib and draw it with the spars
and flaps or aileron.
Once the ribs are drawn,
ribs can be cut from
plywood. The computer drawings can also be cut on a CNC machine.
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