Thursday, August 20, 2015

RV-12 Canopy Latch Instillation Completed

The section of the plans that covers the instillation of the canopy has by far the most pages devoted to it … 23 actually. Last year there was the introduction of the canopy latch micro switch and at that time a few of the canopy latch parts were slightly modified by Van’s to create more of a positive latch and a -1 was added to the part number.  In addition to the instructions for adding a micro switch, section 34 received an additional seven pages which mostly covers various methods of sealing the canopy at numerous locations. A trip was made to the printer so the changes to the plans and the new additional pages could be printed out and inserted into the instruction book.

One of the modified parts is the C-1205 latch block which is now the C-1205-1 latch block. The latch block will be installed under the roll bar and has a trough which captures the canopy latch. Prior to instillation it requires a little finessing by way of countersinking, taping and drilling. The latch block comes with two holes drilled into it and the builder is to countersink the holes for the head of a #8 screw. Easier said than done because there is a trough cut into the latch block and it interferes with the countersinking bit. I ended up taking apart the countersink cage and placing the center portion into the drill press then SLOWLY countersunk down through the wall of the trough and finally into the hole.
Using the drill press to SLOWLY chew away at the wall of the trough on the C-1205-1 latch block and finally on to countersink the hole for a #8 screw. The countersink cage was disassembled and the center portion was placed into the drill press.
Finished machine countersinking of the C-1205-1 latch block. Because of the white on white it is hard to see but zooming in on the photo one can see the wall adjacent to the rear countersink was carved into a little by the countersink bit.

The second hole in the latch plate is a piece of cake to countersink compared to the first hole adjacent to the wall. After both holes are countersunk, the plans instruct the builder to tap one of the holes in the latch block to 8-32 then use it as an aid for tapping the hole in the roll bar squarely. The instructions say to Cleco the tapped latch block onto the roll bar and screw the tap into the latch block and then tap the hole in the roll bar. The idea here is to make a straight square taping of the roll bar. The second roll bar hole is to be tapped after the holes in the latch block are drilled out to #19. Because the holes in the latch block aligned perfectly with the holes in the roll bar, I deviated from the plans and just tapped both holes in the latch block and clecoed it in position to use as a guide for tapping both holes in the roll bar. After the first hole was tapped to 8-32, a screw was placed in the threaded hole to secure the latch block onto the roll bar so the second hole could be tapped … after both holes were tapped, took it all apart, got rid of the metal burrs, final drilled the latch block to #19 per the plans and screwed the completed C-1205-1 latch block onto the roll bar.
Using the threaded hole in the C-1205-1 latch block as a guide to tap the hole in the roll bar squarely using an 8-32 tap.

(Have to mention here that leaving the rear window out has proven to be a golden decision. Working on the latch assembly and adjusting the micro switch would have been much harder if the window were in place). The final piece necessary to complete the canopy latch assembly is to fabricate the C-1214 latch block. The C-1214 latch block is attached onto the aft face of the F-1231F-1 latch plate and level with the latch plate. I made mine just slightly proud about 1/32" … seemed to be a better fit that way. After positioning the C-1214 latch block is to be match drilled to the F-1231F-1 latch plate.

C-1214 latch block clamped onto the F-1231F-1 latch plate for match drilling.
Match drilling the C-1214 latch block using the holes in the F-1231F-1 latch plate as a drill guide.

After drilling, the left most hole in the C-1214 latch block is countersunk for a flush rivet this countersink is to be made deeper than flush. The C-1214 latch block is to be shaped to conform to the shape of the F-1231F-1 latch plate … the Scotch-Brite wheel was used to adjust the shape as necessary. The C-1214 latch plate was then installed using a CS4-4 rivet and two LP4-4 rivets. Because the micro switch and associated wiring has already been installed, all that was necessary to complete the canopy latch instillation was adjusting the positioning of the micro switch. The switch was adjusted so it just barely activates as the latch handle drops into the trough in the C-1205 latch block.
Completed canopy latch and micro switch instillation.