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Read ALL instructions carefully before attempting any installation.
The materials used in the construction of these replacement ribs are all
aircraft type alloys. A great deal of effort has been expended in the
design and testing of this product to ensure that it is "equal to or better
than" the original Piper components which they are designed to replace.
Following the Installation Instructions will provide a high quality
installation and years of satisfactory service.
Installation:
 | Each rib is numbered according to its position along the spars, either
right or left. Follow the installation cross reference carefully to
position each rib correctly along the spar. |
| The replacement ribs are of a "built-up" design as were the Piper
originals. Because of this, the wing components will have to be
disassembled to replace the ribs. The amount of disassembly will depend
upon where the damage is located. Less disassembly would be required if
damage is located near the inboard or outboard ends. Major disassembly
would be required if the damage was located at mid-wing.
When dismantling a wing in preparation for accepting the new rib/ribs, it is
advisable to identify of mark each part as it is removed so it can be returned
to its original position. Inspect each part for defects (see
DC-INSTALL-1, Section 1 for allowable rib splicing locations) and replace if
necessary.
Each rib is attached to the spars with 8 each, #4 type B (blunt point) sheet
metal screws, (see DC-INSTALL-2, Section 6). It is advisable to replace
any original screws that have been damaged during removal or are
rusted/corroded. On wood spar wings, attach ribs as per DC-INSTALL-1,
Section 2.
When the rib/ribs have been reinstalled it is necessary to trammel or square
the wings then tension the brace wires evenly while maintaining square. |
| There are points at which the ribs will encounter interference from the
brace wires, strut attach fittings, or spar attach fittings. These
interference points are identical to the ones encountered by Piper. Each
rib has been "manufactured to fit" each location. There may be occasions
where a previously existing repair or damage may conflict with proper rib
installation. Follow recommendations on drawing DC-INSTALL-2, Section 7
when applicable. Figures 4 thru 6 detail limits for brace wire
clearance.
It is strongly recommended that all ribs be attached to the spars
"temporarily" with a could of screws/nails in each spar. Then proceed
with the installation of compression struts and brace wires. Rib
attachment screws/nails can be secured after all components are in place.
This process can save time and materials should a rib be misplaced during
assembly. |
| The rib mounting holes (on metal spar ribs) have been drilled in a fixture
to produce holes that are at the correct center line distance and alignment
from front to back on each spar. These holes are drilled with a #40
drill and provide a close fit on the #4 attachment screws. |
| When attaching the leading edge to each rib, drill screw attachment holes
offset from the capstrip center web; preferably between the web and the ball
radius edge. See drawing DC-INSTALL-2, Section 4. |
| It would be appropriate to establish a checklist by which the wing
assemblies can be inspected prior to fabric installation. This would
ensure that all component parts are placed and secured properly. Use all
available sources (owners manuals, parts manuals, assembly drawings,
Airworthiness Directives, etc...) to ensure proper installation. A
sample checklist is listed below. Use it as a starting point from which
to complete your own list. |
Note: There are many wing assembly drawing available from the "Cub
Club" 1002 Heather Lanes, Hartford, WI 53027-9045. Phone number
262-966-7627 or e-mail sskrog@aolcom.
They also publish the newsletter "Cub Clues" which features informative articles
written by Clyde Smith Jr. on the restoration and maintenance of the fabric
pipers. This newsletter series provides s wealth of information.
Sample Wing Assembly Checklist
- "Temporarily" install ribs onto spars.
- Install drag struts and brace wires, brace wires should alternately
overlap on alternating bays.
- Trammel wings for square ness and set lock tabs on ends of drag struts.
- Tension drag wires, set locknuts, and tape wires at cross points.
- Install landing and position light wiring (usually under leading edge
skin).
- Pilot Lines installed, connected, and secured.
- Install diagonal bracing at butt rib, inboard aileron rib, tank bay rib,
and tip bow.
- Install leading edge. See drawing DC-INSTALL-2, Section 4 for screw
size and placement.
Note: use drill stops on drill bits to keep bits from penetrating skin
too deeply which may cause bit to hit and nick spar material, (drill stops can
be fabricated from small diameter wooden dowel available at any hardware
store). It is also desirable to build in the proper amount of wing
washout during leading edge installation. This will prevent oil canning
of the leading edge during wing installation and washout adjustment.
Check maintenance manuals for washout dimensions.
- Install aileron false spar. See drawing DC-INSTALL-1, Section 3 for
screw size and placement.
- Check aileron and flap hinge alignment before riveting attach bracket to
false spar. Using the aileron/flap as an alignment tool works well
providing they are not bent or damaged. Drill the attach holes then
cleco the bracket in place. Remove aileron/flap and rivet bracket to
false spar.
- Install control cables and verify routing.
- Lubricate pulley bushings and pins. (Check pulleys for excessive
wear or misalignment).
- Install rib interlace tape at midpoint of rib to hold rib in position
during fabric installation.
- Protect fabric from sharp edges with anti-chafe tape.
- Adhere to fabric manufacturers procedures for attachment of fabric to
structure. Shrink fabric uniformly to prevent fabric from distorting
wing components.
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