Canopy & Turtleback
Rick Irwin let me use his turtleback jig for my TB since his is also 4 inches wider it is a good thing, I hate reinventing the wheel over and over. Held it down with staples. Rick has assured me it will come off the form with minimal damage when the time comes.
Here's where I start to deviate from plans. I am planning a split canopy ala Rick Russell. The back half will open to the side, but the front half is going to be a front hinged canopy. My brother Stuart has engineered it out using the trunk hinges from an audi. Besides flawless movement opening and closing, the hinges have the mounts for the gas struts on them so I dont have to mount some monster struts somewhere that would get in the way.
I made the inserts for the turtleback a bit different. I made one for the front hinged canopy and one for the rear turtleback. My headrest will bolt through the front one so it raises with the canopy. Also I plan a latch, set about 6-8 inches up from closed position to hold the canopy partially up during taxi so I don't have to hold it up by hand. There will be a release lever above the pilots headrest to release it for full open or closed position.
Since I do not have the awful triangle headrests I am trying to find other ways of stiffening up the canopy for roll protection. Besides using flox on all the side exposed foam areas, I used my dremel to router out 5/8 inch depth around the outside curved area of the reinforcements and I filled it with spar tape I had left over from the spar build. I'm not sure the amount of strength this will give the structure, but It's certainly better than the nothing I had before. and with the double reinforcement, that's a section 3/4" x 5/8 inch of spar tape structural reinforcement.
Is that enough? I don't know the math well enough to crunch the numbers and I certainly hope I never have to find out the hard way.
WOW. Here's an example of "your mileage may vary" I had a hell of a time getting the turtleback off the jig. After it came out spent about 2 hours microing the holes the staples and the places the micro came thru. After that cured made a couple of jigs and sanded the edges as per plans and here it's ready for the outer uni layups.
12/9/12 Here's an update... took the canopy off after carving the outside to install the second brace before I separated the front and back canopy/TB sections.
I routered out foam from the inside of the canopy to install wood ribs up through the canopy section to increase strength and torsional stiffness.
Had to make a decision here. The ribs got in the way of the control panel when closing my canopy... Since I had to cut into the plexiglass of the canopy anyways to fit it over the control panel, I decided to alter the shape of the control panel to fit the canopy. I lost a bit of area on the top sides and added tabs on the upper area to widen it to fit the new space... certainly a little different shape from the standard....
01/05/2013 Here's what i've been working on for the last month or so... Jeez it really does add time when you deviate from the plans... I wanted to have this done by new years but it was not to be. ALA Rick Russell I am doing my canopy split. The rear will mostly be for luggage so I didn't like the clamshell door, access is bad that way. I'm just going to use rotary clasps to keep everything down. 2 for the back door and 2 for the FHC( 1 on each side)
Rick was able to get by with a 30lb strut to keep the back up, but I decided to use a 40lb one. it seems to work good. The tensile strength is decent on the rear portion but I did drill a hole thru the turtleback with it in the down position and floxed a 5/16 pin in place to go down into the longeron in the closed position as sort of a guide pin in closing it.
As I mentioned earlier here is my FHC system. This was copied with permission from my brother Stuart Smith (he's a bit ahead of me, but no website.) These are Audi trunk hinges with 130 lb struts on them. They are mounted to triple thickness wood I had leftover from other portions of the plane. These things are sturdy as hell. And you can see my wood ribs under the inside layups running through the canopy. As you can see I have a lot of cleanup work to do, but the big parts are in place.
As you can see from this picture, the rear section comes down on a drip edge on the turtleback, is clamped down by 2 rotary clasps and the FHC comes down on top of a drip edge at the leading edge of the rear section, kinda acting as a secondary system to keep the back from coming open inflight. I still have to install my mechanism to keep the canopy up 10 inches during taxi, but I did want to post these today.