STC MOD FACT SHEET
Cessna One-Piece “Strapless” Windshields |
| Models: | Early Cessna High Wing Aircraft |
| Purpose: | Removes Center Strap Visual Obstruction – makes windshield “One-Piece” or “Strapless.” On some models also increases windshield thickness. |
Models / Part Numbers:
| C-170 A, B (All) | P/N 312/CON, 312/CMB |
| C-172 (Through S/N 17249544) | P/N 312/ CON, 312/CMB, 311/CON, 311/CMB |
| C-175 (All) | P/N 314/CON, 314/CMB, 311/CON, 311/CMB |
| C-180, C-185 (All) | P/N 315/CON, 315/CMB, 316/CON, 316/CMB |
| C-182 (Through S/N 18255844) | P/N 315/CON, 315/CMB, 316/CON, 316/CMB, 339/CON, 339/CMB |
| C-205 (All) | P/N 326/CON, 326/CMB |
| C-206 (Through S/N 2060275, | P/N 326/CON, 326/CMB |
| C-210 (Through S/N 21058715) | P/N 327/CON, 327/CMB, 326/CON, 326/CMB |
The Original Cessna Design: The center strap provides positive retention of thewindshield at the top of the cabin. Positive retention in channel is necessary becausethis area operates in a negative pressure environment and could “pop out” if not positivelyretained.
The LP Aero Plastics, Inc. Mod: The LP Aero STC conversion windshields provide
positive retention through the use of a doubler strip bonded to the underside of the
windshield top edge. This doubler strip engages in a new aluminum retainer strip provided
with the STC windshield (see figure 1). This is the same Cessna-engineered retention system
used on all later model aircraft that use the “Strapless” or “One-Piece” windshield.
This system allows the windshield to “float” in its mount channel yet still be positively
retained. Windshield thickness increases are implemented where the original windshield was
1/8″ or 3/16″ thick.
Competitive Information: All competing “strapless” STCs provide positive retention
by installing screws in holes drilled through the cabin top, windshield, and existing
retainer strip. Cracks are a continuing concern on any installation that requires holes
drilled through the windshield or window, as holes with screws tend to be stressed areas
prone to cracking. The LP Aero Plastics’ Conversion is the only “Strapless” STC that does
not use holes drilled through the windshield and cabin top, allowing the windshield to
“float” in the mount channel.
Options Available: The “CON” windshields provide no mount for the
compass. If the current compass is located on the center strap, it must be relocated to the
glareshield (P/N LP-081 Glareshield Compass Mount can be used – see figure 2) or to the
instrument panel. Relocation is sometimes difficult because the compass may not “swing”
or perform accurately when mounted close to other instrumentation or avionics equipment.
It is best to temporarily relocate the compass and evaluate performance before ordering a
“CON” windshield. The “CMB” windshields are equipped with a bonded compass mount block that
will accept a late-model Cessna “bullet” compass housing and pedestal (P/N SP-CMKT Housing
Kit with new compass, and P/N SP-CHKT Housing Kit without new compass). The existing aircraft
compass most likely cannot be used unless a new bracket is fabricated to match the screw
points on the compass mount block, as the mount block is set up for the late model housing
and compass. The compass mount block can be added to the “CON” windshield in the field but
bonding is difficult with the windshield mounted in the aircraft.
As with all LP Aero Plastics Windshields and Windows, Clear, Green, and Solar Gray tints are available.
