Top Flite Red Box Zero
Wing Construction Log
For Wayne Degeorge, West Seneca, NY
Schwing RC 2003 all commercial rights reserved.
This Zero wing will include functioning split flaps and B&D mechanical retract installation.
PHASE ONE Jaunary 28,2003
Step One- Layout and Parts Modifications for Retractable Landing Gear Installation.
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Modifications to ribs 3,4,5,and 6 required. The retract unit location was determined by the fixed gear strut position and length from the wing plan’s front view. Hardwood mounting rails will extend from rib 4 to rib 6. Rib 3 must be modified also to accommodate the retracted wheels. |
Step Two- Plywood Rib Doublers Required
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The unit located over the plan top view. Ribs must be modified
to accept 1/2x1/4 hardwood mounting rails from r4-r6. These 3 load-bearing
ribs are double with plywood. The R3 rib is also doubled since so much of it
has to be cut out for the wheel well. Relief cuts for the servo pushrod,(or
hoses for pneumatics) have to be made also. |
Retract modified ribs ready to install are shown below. Note right and left method required when fabricating these ribs. Arch shaped cuts in the load bearing ribs are large enough to pass the pushrods required for mechanical retracts, not to mention scale struts. R3 doubler parts were trimmed and used for doubling R4’s, and new 1/8 lite-ply doublers were made for R3 and R6 ribs.
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Once
the ribs have been modified wing construction can proceed as described.
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Phase 2- Build and Join the Wing Frames
Note W7 ribs are slightly undersized in both chord and thickness, 1/16 shims were required to fill the gap at the trailing edge joint. A cap-strip will have to be added to the top aft section of ribs W7 also, before final sanding of the wing frames for sheeting.
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Basic frames complete. Rib notches behind the main-spars
are for routing of bellcrank pushrods. In this case they’ll be the wiring
route for aileron servos. |
Plane the top taper to airfoil shape on the 7/16 trailing
edge before adding 3/8 leading edge of the fixed flap section. |
The flaps on the Zero are the “split” type, top section in
this area is fixed. To make the ribs 3/32x3/8 balsa is cut to length and than
each piece split diagonally with a razor saw, providing 2 sets of ribs.
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Spars trimmed to proper dihedral angle. |
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Plywood joiners in place at the leading edge, mainspar and
trailing edge. Trailing edge filler block has to be installed first. With the right wing half still pinned over the plan,
height under the left tip at the mains-par should be 6-5/8”. Blocks placed
under W7 with jig tabs in prevent unintentional warping. |
January 29, 2003
Phase 3-
Prep for retract
installation.
Phase 4-
Sheet the Wing Top
The Zero’s wing was sheeted with pre-joined 3/32 sheets from the original kit. Skins were joined with Elmer’s carpenter’s glue (aliphatic resin) to insure a uniform surface after sanding. If CA is used the seams will be more resistant to sanding than the rest of the wood skins, leaving hard ridges.
The oversize skins were fixed permanently to the frames with
Everbond epoxy. A very thin film was spread with a squeegee across the inside
surface of the balsa skin and each rib top was painted with epoxy. Jig tabs on
the rib bottoms maintain warp-free alignment while the epoxy sets under weight
overnight.
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Magazine stacks work well for this job. By adding a trailing
edge stock wedge between the stack and skin over the leading edge area, good contact
is maintained while the epoxy cures for accurate airfoil shape.
February 3, 2003
Split flap prep
work must be completed before the bottom of the wing is skinned.
WING DIRECTORY Retract Directory