RV-8A Rear Seat Heat
RV-8A Rear Seat Heat
Since it?s winter, and although I?m not flying yet, here?s my contribution to the RV-8/8A rear seat heat ideas:
Spar Tubes:
1.25-inch flanges (ACS P/N 10350-5)
1.125-inch OD Tube, .049 Wall (ACS P/N 03-36980)
.040 2024T3 Donut Rings (approx. 2.5-inch OD to match flange OD and 1.125-inch ID to match tube OD) (installed between each flange and the spar web)
3M 2216 Structural Adhesive
Aluminum ?Y? Connector (not shown): One 2-inch SCAT to Two 1.25-inch SCAT Tubes
Two 1.25-inch SCAT tubes run from the Rear Spar Face, routed above the floor (to miss the roll servo and trim system), and under a 1.5-inch-depth pilot seat base to just in front of the rear stick. (Note: the two 1.25-inch SCAT tubes have only half the area of one 2-inch SCAT tube. I?m planning to install a 2-inch fan box aft of the pilot?s seat to pull hot air from the 1.25-inch SCAT tubes.)
The rear seat heat source is a dedicated 2-inch heater valve on the firewall. This heater valve is controlled by a cable running from the left rear cockpit wall to the valve. A second, separate heater valve supplies the front cockpit.
Overall system weight (heater valve, cable, SCAT tubing, ?Y? connector, spar tubes, pilot seat base) is approximately +4.5 pounds (2.5 pounds of this is the pilot seat base).
What I would probably do differently next time: For the spar tubes: Use 1.5-inch flanges and 1.375-inch OD tube. Reduce the OD of the 1.5-inch flange to the approx. 2.5-inch OD of the 1.25-inch flanges. Also, the ?flyboykelly? approach (side arm rest consoles) looks promising as an alternative to the spar tubes.
NOTE: I?m planning to use felt to help seal the rear canopy skirt area and reduce vibration (Thanks to Paul and others for this tip). Also, I?ve installed a fiberglass cap over the rear canopy bow, sealed with a ?d? seal on top of the turtle deck just aft of the copilot?s seat (Thanks to a red RV-8 at Oshkosh). Also, I?m planning to add two scavenge holes (Thanks Steve Smith) in an attempt to vent the higher pressure rear canopy skirt flow into the lower pressure tail cone.
This approach is ?Food For Thought,? anyway. Next winter, I hope to report how well, or not well, it works!
Good Luck!
Bill Palmer