I have finished up the front half of the F-18 and have started on the back half. Speedbrake was the first project. There is nothing much available on the speedbrake from Skymaster, so I'll post my process for those that are interested.

You need to start by relieving the rear formers a bit with a rotary tool to get the air cylinder below the brake and to provide an upward angle to the brake attachment point. I threw away the bolts that came with speedbrake kit and used a cap screw and locknut to attach the L brackets to the rear of the piston. I cut a maple block about an inch square and the width of the brackets. With the brackets assembled, I zapped them to the maple, removed the piston and used two servo screws to secure the brackets to the block. With the piston back in place, I epoxied the block to the rear of the former with the cylinder as low as it would go at the rear. I found that if the front of the brackets are flush with the rear of the former, the air line connection is just in front of the former and positions the air hose nicely. See photo.

I then carefully drilled out the speedbrake arms on the speedbrake itself for the large robart hinges. These have double tabs and metal pin. I had to slightly reduce the size of the hinge to make it a bit smaller so I wouldn't have to drill too large a hole in the speedbrake. I used a rotary tool to create a pocket for the hinge point itself. See photo. I then drilled mounting holes in the bottom of the speedbrake arm pocket on the fuse and positioned the speebrake in the fuse. I aeropoxied two ply plates from underneath to hold the hinges to the fuse. Don't glue the hinges into the speedbrake arms yet.

With the piston and speedbrake in place, mark the end of the blue ball joint connector against the bottom of the speedbrake from inside the fuse. I then made a couple of ply plates, routed slots in the bottom of the speedbrake at the marked position, and aeropoxied these in place. I made the plates just big enough to give the ball connector a little clearance to keep as much upward angle on the piston as I could. I also position it in the slots so the piston arm wasn't quite fully retracted to keep positive pressure on the speedbrake when closed. See photo.

At this point, I aeropoxied the hinges into the speedbrake arms. I had to radius the arms a bit to get them clearance in the fuse pocket to rotate up. The last photo shows the final assembly, though the bolt isn't secured yet as I won't do the final assembly until the stabs are in place. Works like a charm.