ExSp33db1rd
23rd Jul 2009, 09:54
I have a problem with a Cessna 182 P - 1975 model.
With the cabin heat shut-off, the heat that is always coming up to the firewall from the muffler shroud heat exchanger, is dumped overboard by a metal flap operated by the knob inside the cockpit, such that the flap - in a sealed box on the engine side of the firewall, just above your passengers knee - lifts through 90 degrees, blocks off the hole through the firewall into the manifold that runs over the rudder pedals, ( and when left open directs hot air to the foot outlets at either side, or up to the windscreen defrost ) and instead directs the hot air downwards, through another hole in the box mentioned, to atmosphere.
Except that mine doesn't, and still lets very hot air into the cabin.
The flap is working, and has been inspected as being OK, but the Scat hose that connects the fresh air vent on the outside to the same manifold over the rudder pedals, gets indescribably hot, and we have to fly with the fresh air vent permanently open to keep things cool. Which does work, but isn't as designed, or right.
Local aircraft engineers have no solution. I am off the opinion that there should be a patch of heat resistant material ( I might once have said asbestos ! ) stuck to the metal flap, so that heat can't transfer from what is a very hot plate of metal, into the cabin.
The Cessna parts manual shows no such piece of insulation.
So what the H--l is happening ?
Anybody experienced this ? Or if you have a 182, have you flown with the cabin heat knob fully in, i.e. no heat required, which is probably the norm. and asked your passenger to feel the Scat hose passing from just above their right knee,forward. If so, does it get untouchably, and unbearably hot ?
If you haven't had the problem you won't know what I'm talking about, but if you have, and have solved it - pls. adv. even PM.
Many thanks.
ExS.
With the cabin heat shut-off, the heat that is always coming up to the firewall from the muffler shroud heat exchanger, is dumped overboard by a metal flap operated by the knob inside the cockpit, such that the flap - in a sealed box on the engine side of the firewall, just above your passengers knee - lifts through 90 degrees, blocks off the hole through the firewall into the manifold that runs over the rudder pedals, ( and when left open directs hot air to the foot outlets at either side, or up to the windscreen defrost ) and instead directs the hot air downwards, through another hole in the box mentioned, to atmosphere.
Except that mine doesn't, and still lets very hot air into the cabin.
The flap is working, and has been inspected as being OK, but the Scat hose that connects the fresh air vent on the outside to the same manifold over the rudder pedals, gets indescribably hot, and we have to fly with the fresh air vent permanently open to keep things cool. Which does work, but isn't as designed, or right.
Local aircraft engineers have no solution. I am off the opinion that there should be a patch of heat resistant material ( I might once have said asbestos ! ) stuck to the metal flap, so that heat can't transfer from what is a very hot plate of metal, into the cabin.
The Cessna parts manual shows no such piece of insulation.
So what the H--l is happening ?
Anybody experienced this ? Or if you have a 182, have you flown with the cabin heat knob fully in, i.e. no heat required, which is probably the norm. and asked your passenger to feel the Scat hose passing from just above their right knee,forward. If so, does it get untouchably, and unbearably hot ?
If you haven't had the problem you won't know what I'm talking about, but if you have, and have solved it - pls. adv. even PM.
Many thanks.
ExS.