The International Cessna^® 170 Association

I've been thinking of making some sort of device to enable me to control the three door vents located on the heat plenum. The idea is to be able to independently control the heat on the right or left side of the cabin. The advantage would be for individual comfort and, when both are closed, to divert more heat to the windshield defroster vent. I don't want to reinvent the wheel, has any one done this already? If not, I was thinking of some kind of a push/pull cable control for each side. I'm still trying to think of how to attach such a cable to the vent doors, any ideas? This is for a '54 B, any ideas or direction to information about prior installations would be appreciated.

Dave

Oops wrong forum .... can this be moved to the Hangar forum?

There are a couple of ways I can imagine accomplishing what you wish. One way would be to copy the heat mixing-valve/cabin-air-shut-off "guillotine" on the firewall, one on each outlet above the rudder pedals. I think this would be complicated.

Another (and what I think, more simplified method) would be to pop-rivet short-arms to each louvre at the rudder-pedal outlets, left and right, and then tie them together with a tie-link, so they would operate in unison, similar to how A/C vents work in automobile dash's. A Bowden cable (control cable such as operates the cabin heat or lawn-mower throttle) could be attached to the "cascade" you've created, in order to open/shut each side individually. I have wished to do this myself, but don't want to mess up my airplane's originality.

I guess the other question would be of legality. If I were to add this mod, what kind of reporting needs to be done?

Dave

Log it as the owner/pilot. (It's an interior upholstery/furnishings modification if you utilize the second method.)

An even simpler method would be to not bother with the Bowden cable after the louvres have been inter-connected. Simply open/close them with your foot/toe.

If you're really motivate (and truly want defrosting capability) increase the defroster vents to two, one on each side. Add a blower and you'll REALLY have capability. (But that would definitely make it a minor alteration and require Form 337.)