Cabin Heat Not Working - Not sure why

[N-43121]

Now that its cold out, I am noticing that I'm not getting much (actually very little) cabin heat output. I have a C-85 with Cessna 150 style exhaust system. The left and right systems are independent. The carb heat is plumbed to the right side and the cabin heat to the left. I've checked to make sure that there are no blockages from the ram air inlet through the baffling at the nose; scat tube to the heat shroud; and scat tube to the cabin heat box. i've checked to make sure that the deflector plate in the heat box is working properly as well. In spite of no obstructions, I get very little air flow through the system.

Anyone else out there with a similar set up experience the same problems? If so, did you get them resolved?

Ideas?

Thanks, Rod

[Hank Jarrett]

Re: Cabin Heat Not Working - Not sure why

When I pulled my exhaust there were a LOT of small leaks in the shroud (poor fit) that lost the pressurized air before it got to the cabin. It only takes a small leak to drop the heat a LOT.
Hank

[magman]

Re: Cabin Heat Not Working - Not sure why

They probably had a similar problem on a C-150.

The solution was a "Scoop" at the Cowl Inlet.

Typically mounted on the horizontal baffle on the right side.

Visible without any disassembly.

Right next to it is another hole.

It is used to collect screws , water & other items.

The intent is to be a "Carb Heat Inlet" however.

[Pearson]

Re: Cabin Heat Not Working - Not sure why

Rod,

I think Hank is onto something with the advice about the small leaks. I would use a laser thermometer to make sure your exhaust pipes are actually heating up. If you are getting good heat through the pipes and there are no obstructions to the airflow going into the cabin, it must be leaks around the shroud. Try plugging the vacume hose on your shop vac into it's outlet hole and tape the other end to the scat tube going into your heater shroud. Put soapy water on the shroud and fix wherever you see bubbles. Good luck!

[swoeric]

Re: Cabin Heat Not Working - Not sure why

my heat shrouds really didnt fit that bad but not great.....i worked on them a bet and sealed them up a bit better....it heat was then 1000 times better

[matsuthunder200]

Re: Cabin Heat Not Working - Not sure why

Rod
I was at charly centers place about a week ago and he showed me a picture of the t-craft that was rebuilt in his shop last year. I think he said it was his brother in law.
Was that your plane??
Also i do have the same set up as you. I have the cessna 150 set up it is set up a little diffent I have a y pipe and duel pa-18 heat boxes. i did have a leak in one of the shrouds and it made the airflow about half of what it is now after i fixed the leak. It wasn't leaking that bad eather. The bigest problem i had was keeping the moter up to temp in -0 weather. I have the middle hole in my nose bowl completely blocked off when it gets below 20 deg. The thing that helped the most is i mad a insulated sheild that felcro's from the back of the seat to the top tube so i only haft to heat the small cabin area works great.. without it all the warm air go's right out the baggage compartment and out the tail.......
I went to the cabin about a week ago was 18 below when i left willow warmed up in about 10 min to where i could take off my gloves and hat.
I do alot of real cold weather flying following the iditerod and the iron dog and just going to the cabin I do have the cold weather stuff figured out after 20+ years of bunny boots and snow gear.

[N-43121]

Re: Cabin Heat Not Working - Not sure why

Rod
I was at charly centers place about a week ago and he showed me a picture of the t-craft that was rebuilt in his shop last year. I think he said it was his brother in law.
Was that your plane??
Also i do have the same set up as you. I have the cessna 150 set up it is set up a little diffent I have a y pipe and duel pa-18 heat boxes. i did have a leak in one of the shrouds and it made the airflow about half of what it is now after i fixed the leak. It wasn't leaking that bad eather. The bigest problem i had was keeping the moter up to temp in -0 weather. I have the middle hole in my nose bowl completely blocked off when it gets below 20 deg. The thing that helped the most is i mad a insulated sheild that felcro's from the back of the seat to the top tube so i only haft to heat the small cabin area works great.. without it all the warm air go's right out the baggage compartment and out the tail.......
I went to the cabin about a week ago was 18 below when i left willow warmed up in about 10 min to where i could take off my gloves and hat.
I do alot of real cold weather flying following the iditerod and the iron dog and just going to the cabin I do have the cold weather stuff figured out after 20+ years of bunny boots and snow gear.

Hi Lance,

Yes, that was my plane that Charly re-built. It seems that I have very little air flow into the cockpit from the cabin heat. I may have a leak in the shroud as well. I just put it on skis this morning and I'm looking forward to winter flying. I used to do a lot of winter flying, but it's been a few years. I like the idea of the insulated curtain and think I'll do the same. I need to do some winterizing.

I would like to visit with you ... and maybe stop by and take a look at your heater set up. Drop me a PM with your phone number and I'll give you a call. I will be out of town for a few days starting tomorrow, but hope to get in the air next weekend.

[Levi]

Re: Cabin Heat Not Working - Not sure why

I was wondering what you guys up in alaska get for oil temp when flying when it around 0 degrees. I am working on a winter kit to block some air flowing over the cylinders for when the temps finally drop here in Maine.
-Levi

[Pearson]

Re: Cabin Heat Not Working - Not sure why

Rod,

Regarding your original question, I was doing some research on another airplane with an A65 Continental engine and ran across something that I had never heard of before that I thought you might find interesting. This is from an Aeronca service manual.

CAUTION: Proper functioning of the heater butterfly valve may be determined as follows:

Set throttle at cruising RPM (2150 to 2200 RPM) Pull heater control on, RPMs should drop not less than 75 RPM not more than 200 RPM.

If no change is noted check butterfly valve for proper seating.

I have never seen anything regarding an RPM drop associated with activating the heater control. Has anyone ever heard of this applying to a Taylorcraft with an A65 engine?

[barnstmr]

Re: Cabin Heat Not Working - Not sure why

Richard,
Although it says heater, I suspect this instruction is intended as carburetor heater function. Operation of cabin heater should have absolutely no effect on engine performance.

[matsuthunder200]

Re: Cabin Heat Not Working - Not sure why

Thats a new one on me.. barnstmr must be right carb heat. I have great carb heat rpm drops about 125
Levi I dont think i would mess around with blocking off any airflow over the cylinders We do block off the hole that lets the air flow on the crank case the middle hole above the carb intake. My macanic wont let me block off none of the air flowing in the cylender holes where the grills go.
Also there is a kit to put on your oil pan and pushrod tubes it is a insulated cover.. I need to get one to see how it works..

[Marv]

Re: Cabin Heat Not Working - Not sure why

Those kits work great in Ohio. Marv

[M Towsley]

Re: Cabin Heat Not Working - Not sure why

The problem I had many years ago with the 'kit' I got from Wag was the tank cover was huge and didn't seem to be made for the A-65 tank. The people I spoke with at Wag didn't seem to be interested in fixing it, either.

[jmvolpp]

Re: Cabin Heat Not Working - Not sure why

I block the hole above the carb air inlet and use the insulated long underwear kit and maintain about 140 degree oil temp on the coldest days here in Hoosierland. Remember to turn out the idle mixture screw 1/2 turn also, for the winter.

Mike V.

[Levi]

Re: Cabin Heat Not Working - Not sure why

I have the center hole only blocked and had an oil temp of 140 ish this past weekend with the out side air temp of upper 30's. I was worried that when temperatures gets colder the oil temp wouldn't come up enough. I looked around on wag aero for the winter kit but couldnt find anything, is it still availble?
-Levi