Golden
Era Model Service
High
Quality Plan Sets for Radio Control Aircraft
74 inch San Josè
A 1948 design by Antonio Arria
Holes drilled and threaded.
The stabilzer was
installed to help keep the fuselage aligned while the threads were
tensioned. The threads end up at the same place on the
fuselage on each side and are pulled down "smartly" as the Brits would say by a substantial weight. When all is right the threads are
glued
with gel CA at each hole location. Finally, after the weight is
removed the ends are run through additional holes and glued.
30 pound Kevlar was
used for control cables. These are the rudder exits, found by
pulling the cable tight and changing the routing
through the fuselage repeatedly until a clear straight route is found
to the control horn from the servo. The small fuselage cross
section
is a hindrance but it worked OK with a tweak here and there such as the
grooves filed into the bulkheard here. The slot
location was found by sliding the precut 1/64 ply sheet along the longeron and stringer until it touched the string.
A line was drawn on the ply and a slot was routed along it.
3 layers carbon fiber tow was CA'd to the bottom of the subfin and sanded to smooth it out.
The elevator string exit locations.
After preliminary balancing the battery retaining 1/4 square balsa was extended back to F3 and a 1/64 ply plate
was inserted on the front of F3 as a battery stop. Foam blocking will be used to position the battery.
A
top view of the rudder thread exits. The aft fuselage was covered
with a single sheet of covering, starting at the bottom longeron
and continuing on around to the bottom longeron again.
As the covering was wrapped around the hole locations for the
string
exits
were found and burned in with a small soldering iron, which toughens
the covering against rips. The threads were routed
through the covering and the covering process continued. The
front and back covering areas were joined at the F5 bulkhead.
I covered the front section first which is backwards but it may
be the best way as it is easier to determine the cut on the aft section
at F5 as it can be wrapped around tightly and tape can be applied to use as a guide for cutting the material when it is off of the airplane.
I was very much surprised later on when the fuselage was covered at how much stiffness the covering added to the aft fuselage.
Because of the small cross section in the last bay the threading
is a good idea there, but it is unclear to me whether stitching the
middle bay was needed and it is cetain that it is not needed in the bay
behind F5. Transparent Ultracote was used for covering.
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