Saturday, August 8, 2015

Instillation Of The C-1201 Canopy Begins

The clearance issue mentioned in the previous post regarding the WD-1219 canopy frame hitting the F-1240 upper forward fuselage skin was easily resolved by placing washers behind the canopy frame as Van’s instructions suggested. A piece of stiff cardboard was placed between the F-1240 skin and the canopy frame so the frame could be lifted up without snagging the F-1240 skin. With the canopy in the up position the mounting bolts were removed one at a time. While Mike held the canopy frame, the washers were stuck onto masking tape and slid onto the bolt. The right side required two washers and the left side only one.

Two washers added behind the canopy frame on right side to adjust canopy frame outward to clear the F-1240 upper forward fuselage skin. The right side required a single washer.

With the canopy frame clearance issue resolved, work continued on preparing the canopy frame for the canopy instillation. Van’s instructs the builder to cut 1/8" thick cardboard and place it on the left and right canopy deck. The cardboard (which can be seen quite clearly in the second photo below) will become a spacer and also prevent the canopy frame from rubbing the rivet heads in the canopy deck. The canopy frame is to lay flat on the cardboard which will establish a 1/8" gap between the canopy deck and the canopy frame so the frame was tweaked accordingly. The same 1/8" gap also applies to the gap between the F-1254 support frame and the aft portion of the WD-1219 canopy frame. Next the canopy side to side positioning was tweaked. Of course, making adjustments at any one location affects other locations so it is a test of patience, going back and forth making small corrections until, in general, it is close enough. Next four C-1211 wooden spacer blocks are placed in the gap between the canopy frame and roll bar to lock in the proper gap between the two.
After getting the WD-1219 canopy frame to sit with the proper clearances, four wooden C-1211 alignment blocks are clamped in the gap between the roll bar and aft canopy bow.

The next step is to install the C-1203A&B canopy attach angles. The angles were drilled and fluted per the plans long ago so they could be painted … all that was required now was to align the angles with the inside edge of the canopy frame and use them as a drill template to match drill the WD-1219 canopy frame.
Using the predrilled holes in the right C-1203A canopy attach angle to match drill the WD-1219 canopy frame using a #30 drill bit. Note – the 1/8" thick cardboard spacers can be easily seen in this photo.

Upon completion of the match drilling the canopy attach angles to the canopy frame, all the C-1203A&B canopy attach angles were riveted onto the WD-1219 canopy frame using LP4-3 pop rivets.
Riveting the left C-1203A canopy attach angle onto the WD-1219 canopy frame.

Now that the canopy attach angles are riveted onto the canopy frame, the next step is to fish out the canopy from the shipping crate and prepare it for instillation. Van’s instructions suggest the builder remove approximately three inches of the protective film from the edges of canopy … but leave the remainder of the film on the canopy for protection from scratches.
Bernie, Mike and Moi pealing back the tenacious and sticky plastic protective film from the C-1201 canopy to prepare it for fitting onto the WD-1219 canopy frame.

Prior to installing the canopy onto the canopy frame for the trial fit, a strip of painter’s masking tape is to be placed over the forward bow in the canopy frame just aft of the instrument panel but not pressed down. The idea here is once the canopy is positioned, the portion over the bow is to be pressed down onto the bow. This will leave a faint mark in the tape at the contact point where the canopy was pressed down onto the bow. This will create a line of contact where holes will be drilled for riveting the canopy onto the bow. Bob, fellow builder in Wisconsin reported having great results using carbon paper in the place of tape to make marks on the bow where the canopy touches the bow. Unfortunately, the DOG Aviation procurement department dropped the ball and forgot to get some carbon paper to try this seemingly sound technique … so the masking tape method was employed.
C-1201 canopy sitting on the canopy frame for the trial fit. Note the blue masking tape covering the forward bow just aft of the upper forward fuselage skin.

All and all the canopy fit was good - the left side was perfect but the right side is slightly off … but will be OK just not quite as perfect of a fit as the left side. The cutout on the forward portion of the canopy may need a few thousands removed, but over, all it looks good. After removing the canopy, the painters tape on the bow is to be marked for drilling beginning on either side of the center weld and making marks at 2" intervals on the line left on the tape from contact with the C-1201 canopy.
Looking closely, one can see the line created in the tape where the canopy pressed the tape down onto the bow. Drill marks are placed onto the tape where the line was created at the pressure point where the canopy pressed the tape onto the bow. The drill marks are placed at 2" intervals per the plans.

Unfortunately, did not have time to drill the bow because of a commitment, so that will be the starting point for the next work session.