Q1 Plans Chapter 15 Page 15-1
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- Category: Quickie Plans
- Published: Monday, 12 May 2008 10:28
- Written by Dan Yager
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THE CANOPY
The canopy is sent to you molded to shape. It is crated to protect it from scratches during shipment. We suggest that you protect your canopy from scratches by spraying or brushing on a “peel coat”* or by taping paper or plastic over it for protection while you are building the frame and while you paint the aircraft. Leave this peel coat in place except where you need to remove it to lay down grey tape or lay up glass. When your canopy is complete and the airplane is painted, this coating will peel off easily.
Trim the canopy plexiglass along the premarked lines provided. A band saw, an abrasive cutoff disc in a hand held grinder or skill saw, or a saber saw, will do the job, but in any case, go slow or you’ll ruin your whole day (not to mention your canopy). We've found that the abrasive disc is the easier method. Another excellent tool is the number 406 steel saw blade (about 1” diam. disc) that’s available as an accessory for your dremel hand grinder.
Laying down a layer of grey tape on both sides of the cut line will not only help guide you, but also help minimize breakage.
Remove all nicks from the plexiglass edges with a file. Polish the edges with 320 grit sandpaper. Nicks or scratches can start cracks in the plexiglass.
Next, make the aft canopy bulkhead, and locate the left side and right side canopy stiffeners that you made back in the fuselage section.
The canopy must be fit to your aircraft. You will find that you have to fit and trim several times before you are satisfied. Read over this entire chapter before preceeding to understand what it is you are trying to accomplish. Basically, the tighter that the canopy fits the fuselage, the more airtight and attractive it will be.
Bondo the forward fuselage cover to the forward fuselage. (Several dabs)
Lay three layers of grey duct tape along each longeron from the seatback bulkhead to the instrument panel bulkhead on the right side, and 4” forward of the aft edge of the forward fuselage cover on the left side.
What you will do next is to jig the Aft Canopy Bulkhead and the two canopy stiffeners in position on the fuselage. You will then do the final fitting and trimming of the canopy on the fuselage, and then permanently mount the canopy to the stiffeners, the Aft Canopy Bulkhead, and the front cockpit cover.
The Aft Canopy Bulkhead is located 0.3” forward of the top of the seatback bulkhead. This is to allow for the later installation of an aft canopy seal. Several foam chips can be used to space the bulkhead out.
The right side canopy stiffener extends all the way forward to the instrument panel. The left side canopy stiffener extends forward to the rear edge of the forward cockpit cover. These stiffeners rest on the grey tape that you previously place on the longerons. Note that the right side canopy stiffener requires a notch in the forward cockpit cover so that it can pass forward. Use Bondo or five-minute dabs to join the stiffeners to the aft canopy bulkhead and the front cockpit cover.
| * | For “peel coat”, you can use Spraylat “A” you need about 1 qt. - Cowley, Inc. Bldg 170, Mojave Airport, Mojave, CA 93501 805-824-2368 |