High Quality Plan Sets for Radio Control Aircraft
Henry Struck's 1937 Benny Boxcar
Scaled to 108 inch span
Page 24
Fortune smiled and the surface travels worked out well with no transmitter adjustments to servo travel. It is best to use servo arms that have the same distances between the points the cords are attached
as do the surface control arms. The larger that distance is, the easier it will be to tension the cords to limit surface free play without developing extreme tension. There will be less binding in the control circuit
as well which improves the centering of control surfaces. The Kevlar cord does not change tension with temperature not does it creep while under tension. It has high resistance to fraying.
A slotted 1/16 balsa plate was installed where the lower elevator cord entered the fuselage. The cords will be left in the fuselage while it is covered. They will be pulled through small cuts in the covering as it progresses past the interception points.
The upper interception points. The upper elevator cord is the one most forward.
The covering has been attached up to the left side of the slot, the slot is melted in, the cord is pulled through and then the covering is attached the rest of the way to the tail end of the fuselage.
About 5 rolls of Ultracote later the Boxcar 108 is covered. There was a lot left over to cover small models with but the 16 inch chord of the wing uses up full rolls at an alarming rate. Doug Barton polishes off the last of the building dust.
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