Top Flite S.E.5A - Manual (Page 16)

PRE-FLIGHT CHECK
This is probably the most important Job to do on any model Right here is
where the complete success of the maiden flight is organized A somewhat tire-
some task to do properly, but hurry here can lead to an expensive crash Let's
break down the pre-flight check into three units.
1. Balance
2. Alignment
3 Equipment
First, balance. The model should balance level to the ground or slightly
NOSE DOWN when supported by its wingtips on the fingers or some blocks at the
point marked CG on the plan (sheet 2) This is exactly half-way between the
leading and trailing edge of the upper wing
Due to the naturally good layout of the S E 5A for modeling, it will
almost always balance properly However, if it becomes necessary to alter the
balance point, try to do so first by moving some fairly heavy item of equipment
(such as the battery) to a new location If this is not possible, weight must be
added to nose or tail
However, much is needed this must be put in the model While it is admittedly
a shame to add, say, half a pound of dead weight, it is the only answer Never
be trapped into thinking that the extra weight will do more harm than incorrect
CG location'
If your model is nose heavy (CG too far forward) the worst that can happen
is a slight sluggishness in control response This presents no problem and can be
rectified before the second flight. With tail-heaviness, however, there is frequently
NO second flight'
Second, alignment. This check consists of finding out if the incidences of
the wings and stab are correct Proceed as follows Stand the model on its wheels
on a level surface—a dining room table will do fine Now block under the tailskid
with books, etc until the measurement from the table up to the L E of the stab
is the same as up to the T E of the stab It is important, of course, to have
previously set the elevator at dead neutral Having got the stab accurately parallel
to the table, measure the incidence of the lower wing
To do this, measure up from the table to the middle of the L. E at the
dihedral break Make a note of the figure Now measure from the table to the
T E point, at the same dihedral break This second figure must be somewhere
in the range of The same as the first figure to 3/16" less than that figure. (That is,
between 0° and + 1 ° incidence)
Finally, check the upper wing incidence This is very simple At the same
dihedral break as used before, measure the L E bottom to-L E top wing then
the T E bottom to T E top wing The figures should be the same It is allowable
to have slight positive incidence on the upper wing relative to the bottom one
That is, if the T E -to T E measures 1/8" or so less than the L. E.-to-L. E. figure,
do not be concerned
As long as care was taken during the construction it is doubtful that the
alignment will prove to be wrong beyond the tolerances allowed If, however,
such is the case, make the necessary alterations by regarding the lower wing as
correct and aligning the upper wing and the stabilizer to this Trimming the length
of the two forward or the two rearward cabane struts will decrease or increase
the incidence of the upper wing respectively (also trim the interplane struts to
match), the stabilizer can be brought into alignment with the lower wing by cutting
it free from the fuselage and re glueing it back after trimming-out the rear fuselage
sides to change the angle as required
Lastly, equipment. Switch on the radio and check carefully all control surfaces
for free movement Eliminate any over freeness that could cause rattles Check
motor control Do not be satisfied with less than full 100% perfection in this area'
To lose a good model from accidental causes is bad, to lose one because of hurried
checking of RC equipment is unexcusable because it could have been avoided.
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