Progress is frustrating slow. Too many other things going on. Last Sunday I spent most of the day with Terry as we haven't had much time together lately. We had company here from Monday until Thursday, so I didn't get much done then either.

Today I made a trial rear seat riser out of scrap plywood from one of the kit shipping crates. I'm not sure who first came up with the rear seat riser idea, but Cleaveland Tools created the plans that I am using (full size plans). The RV-4 and RV-8 rear seat cushions sit right on the floor. The RV-8 does have sunken foot wells for the rear seater to put his feet in, which helps a bit, but the basic seating position does have the butt fairly low. The rear seat riser is a platform that lifts the rear seat cushion about three inches off the floor at the front, and slants back to be about 1.25 inches high at the rear. I wasn't sure those dimensions would be ideal for my aircraft, so I decided to make one out of wood to test out the dimensions before making the real one from aluminum sheet.


I placed the two vertical plywood supports so they would sit on top of the seat ribs that support the floor. I didn't want those plywood pieces to end up a bit off the seat ribs if the riser slide sideways, as that would force all the weight to be supported by the thin aluminum floor. So, I put a short nail in the bottom of each plywood rib so that it would fit into an empty screw hole on the seat ribs and prevent the plywood from moving.


I put the seat cushions in place on the rear seat riser, climbed in and pulled the canopy closed. I found that my head was a bit too close to the canopy, so I pulled the one inch booster cushion off the bottom of the rear seat cushion and tried again. That seemed to work reasonably well, but I'm not a big guy. I'll get my coworker Jim over to try it out. I suspect I may have to lower the top of the seat riser a bit to better fit tall passengers. The RV-8 canopies are free-blown, rather than being made in a mold. So every canopy is a slightly different shape, which affects the amount of head room in the rear seat. My canopy may be slightly lower than average, which would also change the angle that it sits on the frame. This would be consistent with the fit problems I had on the canopy skirt.

There is a cutout in the rear seat bottom cushion to make room for the movement of the control stick. I get the impression that the stick might rub against the seat cushion if the stick is full aft with a large aileron input. I won't be sure on this one until I get the aircraft assembled with the controls hooked up.