6mmFlyRC F-14 Tomcat Instruction Manual - page 13
Page 13
15.
Make the 1/8” lite-ply servo arm, and then attach a nylon servo arm with
two screws as shown. You may need to experiment to find the exact hole
locations that result in both wings swinging identically forward to back—
and those locations will probably NOT be symmetrical. I found that the left
wing needs a little longer moment arm than the right wing to swing equally.
If one wing swings more than the other, simply increase the moment arm
on that side. The locations shown on the plans are what worked (after
much experimenting) with the HS-81MG servo used in the prototype.
Also note that if this horn seems weak to you (only .25” wide), that’s by
design! This servo arm is intended to be the weak link in the wing swing
mechanism. That way, if you catch a wing on landing, this horn will break
before anything else in the system breaks. This is good because this horn
is easy and quick to replace via the hatch in the top of the fuselage. This
design has already paid off for me—I had a crash landing in one of the
early flights and this arm broke just as intended, preventing any further
damage to the wing or swing mechanism!
16.
Glue 1/8” lite-ply strengtheners to the bottom of the servo tray as shown.
Then check the fit of the servo and trim as required. When done, the
assembly should look like the picture on bottom.
I used a Hitec HS-81 MG servo on the prototype, which works OK but is
definitely strains in this application. I think it works well enough that a
larger (and thus heavier) servo isn’t required, but if you choose to do so
there is room for a larger servo. The most important thing is to use a
METAL geared servo (a nylon geared servo is very likely to strip).