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Aerogram December 2009
lines. Place fuselage on two trestles, one under strut
three, and the other under strut nine. Trestles to be high
enough to allow for fixing of undercarriage.
Pack up trestle under strut 3 until laterally level. On strut
1 to 4 mark 15,1/4” down, on strut 5- 15,1/16” on strut
6- 13,1/32” on strut7- 11,5/16”on strut 8- 9,1/2”on strut
9-7,25/32” on stern post 6”
All these measurements are taken from the top of top
longeron on each side of fuselage, and these marks are
the datum lines when the fuselage is trued up. Fix
sectional straightedge on fuselage by clamps to the
marks on struts 1 and 9. Straightedge to be laterally
level, and between these stretch chalk line taut on both
sides of fuselage, the straight edge to coincide with chalk
lines, irrespective of the marks on struts, and pack up the
trestle under strut 9 until the section straight edge and
chalk line (checked by level on straight edge) are exactly
Order of Trueing Up
internal section 2nd side’s 3rd bottom 4th top.
Trueing Side Section
The top longerons from strut 1 to 4 are to be
longitudinally, adjust bracing wires until the marked points
on struts from 1 to 9 coincide with the chalk line
stretched from the section straight edge.
The side struts and sternpost to be kept perfectly plumb.
Trueing Bottom Section
Mark exact centres on all bottom struts of fuselage.
Trammel bay where king socket fitting are secured by
checking diagonals, which must be equal. Stretch lines
from the centre of struts of this bay so as to reach struts
of next bay, and adjust bracing wire until centre mark on
this strut agrees with the line.
Trueing Up the Main Plane
In trueing up a main plane it is essential to find xxx if the
centre of holes of the main spar socket fittings are to be
square with the front of spar of the plane. This is done by
checking measurements laterally across fuselage as
dimensions 3 to 4 and 5 to 6. If these are essentially
equal, then the root is exactly square and parallel with its
axis of fuselage, but if these lengths are unequal then the
distance B to 1 and D to 2 will be unequal. Mark on
centre line of front spar at A and B exactly opposite the
compression struts then measure distance from B to1.
To find point D on rear spar add or deduct the distance
B1 half the difference in length from 3 to 4 and 8 to 6
(remainder of entry obscured).
2 1/4% incidence
Incidence of tail plane nil.
Line of flight, parallel to the longeron
Longerons are made of solid Ash
Fuselage compression struts are Spruce
Bracing wires in fuselage are piano wire
Spars are Spruce boxed out
The leading edge is Spruce
Trailing edge is oval steel tubing
Ribs are made up of 3 ply and spruce
Interplane struts are Spruce
Centre cellulite struts are streamline steel tubing
Chassis struts the same.
The landing, flying, centre cellule, chassis bracing wires,
and drift wires are made of cable wire.
Dismantling a Sopwith Schneider
The first part of a Sopwith Schneider to be taken down is
one of the top main planes. Then take down the other
top plane. In taking down the top planes do not unfasten
the landing wires; otherwise a trestle has to be put under
the bottom plane to take the weight of the wing tip.
Then take down the bottom planes. When placing the
planes on the ground, care should be taken not to
damage the edges. To prevent this planes are usually put
on two pieces of wood. The next thing to be taken down
is the rudder, then the stabilizing fin, elevator and tail
plane. After this, pack up under the fuselage until the
floats clear the ground, then take off the floats and
undercarriage. Then let the fuselage down onto the
ground and take down the centre cellule.
The centre cellule is the first thing to be re fixed. Before
raising the fuselage it is advisable to true up the cellule
and get the correct stagger. This can be done by packing
the machine up to flying level, and dropping a plumb-bob
from leading edge of the root of the top plane and
measure the correct distance to the root of the lower
plane. Then raise fuselage high enough to clear the
undercarriage and fix the chassis struts. After this put on
the floats and true up the chassis. There are two ways of
doing this. One is to get the planes to flying level
longitudinally and laterally, find the centre of the fuselage
directly above the floats. Drop a plumb-bob between the
floats centrally. The other way is by trammeling. Then put
on the tail float. After this is done, the bottom planes, and
after them the top planes are to be fixed. Then re-fix the
tail plane, stabilizing fin & the rudder. The fuselage has
then to be put at flying level, and then you can start
truing up. The first thing to get right is the dihedral. This
is obtained by means of a dihedral ball and spirit level.
The dihedral of a Sopwith Schneider is 2%. Then get the
correct incidence with an incidence board. Then get the
tail plane true and adjust the rudder and elevator control
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