At 06:38 AM 8/19/2006, you wrote: >I used 3/16 AL---------Put a 1/4" plywood doubler on the bottom of the fuse >directly behind the rear spar, that stiffened everything up and gave me a >good mounting point for the hinge. My board and mechanism was my design, it >works like a mouse trap, spring loaded in the up position at all times, that >way all u need is a 1 way flap handle setup. >Kenneth Wiltrout ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
A piece of 1/4 inch foam will work and save some weight. Mine is 9X30 inches with a piece of 1/4 inch spruce in the lead edge for the hinge and a small block in the push-down rod attach area. I placed a strip of 1/4 inch spruce on the fuselage floor just behind the rear spar like Ken and used the "wood washers" with 5 each 3/16" bolts to attach the hinge. If you weight the foam when the glass is wet you can get it to conform to the shape of the fuselage bottom. I tapered my board at the edges on three sides to fare in to the fuselage and built a small air ramp to fare in the lead edge and hinge. My single jack screw push down is slightly off center to allow for the elevator cables routing. I placed a number of 3/4" holes across the board in several rows for additional drag. I regularly lower the board a 110 mph indicated with no problems to date. When deployed, I get a noticeable nose up pitching and a very noticeable airframe buffeting. It does not seem to affect the handling characteristics in pitch, roll, or yaw in any way. The hinge is attached to the board with glass and flox only with many 1/8" holes in the hinge for epoxy/flox flow through for better adhesion. http://mysite.verizon.net/flesner/19.jpg http://mysite.verizon.net/flesner/02092593.jpg My board is electrically operated but I like Ken's idea of the spring loaded up for a hand actuated board. A fast retract is appreciated for a "go-around". Mine takes 7 seconds but that can seem like 7 minutes as you approach the tree line ! Larry Flesner
