HEAT IN COCKPIT

[Ron Franks]

Hey guys and gals! I have an early 1962 Comanche 250 with a cockpit heat problem. When I first bought the airplane, the doggone thing would just cook me in this Texas heat! At the advice of several people I talked with at the Oklahoma convention, I put a dual exhaust system on the plane about a year and a half ago, and it cured most of my cockpit heating problems. Now it runs cool (or relatively so), until I start slowing for gear and flaps in the pattern. I get a blast of hot air that seems to come from under the instrument panel and continues through the roll-out. I'm sweating enough in the approach and landing already - I don't need something making me even hotter. Any ideas what's causing the heat??

[William Hughes]

There are push-rods attached to the rudder pedal system that go through the firewall and attach to a bell-crank that rides on the nose wheel strut to allow steering. They are sealed off by a rubber boot. These boots break down and can allow hot air right off the exhaust system to blow into the cockpit. As you slow down the angle of attack increases and the airflow also slows down. So you get higher pressure hotter air blowing into the cabin. I replaced the boots (they are cheap) and my exact same problem stopped.

I have heard that you can reverse them with the rubber boot pointing into the cabin to help prevent degradation but I installed mine per the manual.

Perhaps that is your issue?

William

[Andrew Foster]

Ron,

I would agree with William, it does sound like the boots. Ours are installed on t he inside of the cabin, vs outside. You should also check that the diverter valve in the two heater boxes, right and left side are fully closing.

Good luck

Andrew
61 250

[Ron Franks]