The International Cessna^® 170 Association

I have been reading with some amusement this morning of "improvements" in cabin heaters after 1952.
You people must be Vikings!
I am a former commercial fishermen with many winters off New England under my belt, but this airplane had brought me to my knees.
My 170 is a 1955 model with all three winter baffles installed. Flight is tolerable from 20 to 30 degrees Fahrenheit, but from the teens on down, forget it.
I flew yesterday in the single numbers (Fahrenheit) and my feet, which almost never get cold, were like blocks of ice.
I have read where some of you have engineered modifications in the name of heat. That is not an option for me; as we say in Maine, I couldn't put a button on an outhouse door.
I used to instruct in a 150 that was so drafty we would stuff a jacket (yes!) around one door on winter cross countries, but other than that we thought nothing of it.
This airplane isn't drafty, it's just cold.
What are my options, other than a magnetic heading of 225 and three fuel stops?

They are all drafty. Do you have a wool headliner? Lots of cold air comes in from the tail boom. I have a vinyl headliner and I tape up the speaker holes cuz it's like a waterfall of cold air right down on my shoulder. I plan to make bulkheads to better seal that off.

Check your heat muff for obstructions. Maybe a birds nest is blocking the inlet?

Also, your heat valve may be worn out (the flapper valve has baffle material to seal it. If it's old worn and cracked, you could have lots of cold air premixing with the warm air before it hits your toes.

My heat duct inside the plane (1952) gets to about 220 degrees. I'd imagine yours should be the same so check it in flight with a fancy laser thermometer.

Take a strip of paper and close it in your doors to check how well they seal. Check all around. It the paper can call out or has no friction, you're getting cold air there. Don't over do the seals tho as it puts a big load on some very expensive hinges. I used AviationDepot memory foam insulation strips and trimmed it with scissors to the right height for each section of the door.

If all else fails, heated socks and a heated seat cover will work wonders.

One thing's for sure: There is no way the air coming out of that duct is 120, let alone 220. So we will start there.
Thanks

Your '55 model should have plenty of heat, IMO.
I did install a bulkhead above/aft of my rear bagg shelf to stop the airflow from the fuselage migrating into the cabin (which also reduces exhaust and noise ingress.)

Good cabin door seals are a MUST. Also, inspect/repair the entire cabin heater system, from mufflers to heat-valve, to distribution ducts (which have many times been found full of mice-nests in some airplanes.)

It sounds between you and David as though I am not getting my full measure of heat via the ducting. Which I don't doubt, I used to fly around in a '57 172 and cabin heat was not an issue.
Assuming there is no nest how should the heater valve assembly look when heat is full on (maximum heated air). I wonder if I am getting the full throw.

N3548C wrote:It sounds between you and David as though I am not getting my full measure of heat via the ducting. Which I don't doubt, I used to fly around in a '57 172 and cabin heat was not an issue.
Assuming there is no nest how should the heater valve assembly look when heat is full on (maximum heated air). I wonder if I am getting the full throw.

Check for mouse nest in the ducts.

Make sure those winter intake covers are not blocking off the incoming air flow to the muffler. I personally do not use intake air restrictor plates because they can cause problems such as you are seeing. It sounds to me like there is not enough supply air for some reason which in turn will not move the heat into the cabin. Something is restricting air flow somewhere or there is a major leak between the intake scoop and firewall valve. Even if the firewall valve flapper seals are completely gone, you should be getting more heat than you are.

I really like how this heat tube turned out on ____'s 52'

54170b wrote:I really like how this heat tube turned out on ____'s 52'

It's nice, but I might as well attempt to build the space station as re-create that installation.

I found on mine between the firewall and the next bulkhead a short section piece of ducting hose torn. After I replaced it was a different heater.

John

N3548C wrote:

54170b wrote:I really like how this heat tube turned out on ____'s 52'

It's nice, but I might as well attempt to build the space station as re-create that installation.

My heat box was damage on my 54' so I installed this one and it took me 2 hours to "re create" this installation. I can send you my measurements if you like

I haven't been to the airport this work week but the mechanic I use looked it over and said via email the cabin air valve wasn't open all the way. He rectified things and said "You should be all set."
I do not know whether he was speaking with respect to the cabin controls (which I believed to be set to max) or the actual valve, but I will look it over this weekend and if possible, fly it and report back.

N3548C wrote:I haven't been to the airport this work week but the mechanic I use looked it over and said via email the cabin air valve wasn't open all the way. He rectified things and said "You should be all set."
I do not know whether he was speaking with respect to the cabin controls (which I believed to be set to max) or the actual valve, but I will look it over this weekend and if possible, fly it and report back.

It may sound a bit counterintuitive at first if you aren't familiar with the system, but for maximum heat in a late B-model, the "fresh air" must be full ON (control pushed all the way IN). This valve is downstream of the heat diverter valve, and it's purpose is to isolate the firewall forward from the cabin in the event of smoke/fire in the engine compartment. When this valve is closed (knob fully out) there will be no air, heated, fresh, or otherwise, getting from the engine compartment into the cabin.

I never made a habit of it, but at least once I took off in single digit (F) weather and climbed to -20 OAT and my stock '55 heater kept the cabin warm enough to shed gloves and hat (and at that point I'd lived my entire life south of the Ohio River, so I'm definitely NOT a Viking! )

cessna170bdriver wrote:
It may sound a bit counterintuitive at first if you aren't familiar with the system, but for maximum heat in a late B-model, the "fresh air" must be full ON (control pushed all the way IN). This valve is downstream of the heat diverter valve, and it's purpose is to isolate the firewall forward from the cabin in the event of smoke/fire in the engine compartment. When this valve is closed (knob fully out) there will be no air, heated, fresh, or otherwise, getting from the engine compartment into the cabin.

I never made a habit of it, but at least once I took off in single digit (F) weather and climbed to -20 OAT and my stock '55 heater kept the cabin warm enough to shed gloves and hat (and at that point I'd lived my entire life south of the Ohio River, so I'm definitely NOT a Viking! )

That's where the controls are set. Flew it yesterday, quite comfortable but the OAT was in the 40s. So I'm skeptical it will be comfortable when it gets cold... so something may be going on... or not. It's going to colder soon, though, so we'll see.