I'm Tired of Being Cold (My Solution)

[Garrett Gee]

It seems that my CTLS is just drafty.  I have tried just about everything on the forum to try to keep it warm, to no avail.  Now, it doesn't help that I just hate cold.  I have sealed the doors, taped the overhead opening, adjusted the heater valve, checked the shroud, checked the intake, and it just seems my heater is just to anemic.

I got tired of having to fly in a big  winter coat and vest and long sleeve and thermals, so I (probably over) engineered a solution.  Did a little reverse engineering on the CT heater ducts, and made up my own in CAD.  With the added benefit of a high output fan in the mix.  Had it 3D printed in flame retardant Nylon 12.  This things moves about 10x more air than my poor little stock cabin heating system.

Haven't installed yet, but will report back once I get it going!

 

[Roger Lee]

Hi Garrett,

Give me a call and I can help you seal up the cabin and make sure the heater is working properly. I could fly in my SW in the teens and 20's  with nothing more than a shirt on.

I hate the cold too. That's why I live in southern Arizona. That said we've had snow twice in the last 4 weeks. LOL

[Eddie Cesnalis]

I have countless winter flights @ ~13,000' in my CTSW.  Talk to Roger, you don't have to be cold.

[Chuck]

That is some impressive CAD and 3D-printing - kudos!!!  I’ll be curious for the performance report.

 

I went flying this morning in northern NH around the white mountains with OAT of 13F. Flight went fine, with the defroster and cabin heat keeping up adequately.  Just before leaving the hangar though I tried to clean a few streaks off the windshield with my PlexiClean. As soon as I misted it onto the windshield it completely froze. Took me 15 minutes of rubbing to clear it. The days not over yet, but I’m hoping that’s the dumbest thing I do today…

[Anticept]

The air going through the system is hot enough to melt the rubber on shoes when it works. You might end up with a melted mess.

When the system works too well, it can also damage the windshield. Have one CTs with window damage from it.

[Eddie Cesnalis]

2 hours ago, Anticept said:

The air going through the system is hot enough to melt the rubber on shoes when it works. You might end up with a melted mess.

When the system works too well, it can also damage the windshield. Have one CTs with window damage from it.

True Dat    I have burned my foot too many times.  I have a nice difusser there now

[Garrett Gee]

7 hours ago, Anticept said:

The air going through the system is hot enough to melt the rubber on shoes when it works. You might end up with a melted mess.

When the system works too well, it can also damage the windshield. Have one CTs with window damage from it.

That's good to know.  I didn't realize that, as my heater has never been that good in the 5 years I have had the plane.  I know everything is fairly well sealed but, but it seems airflow (specifically volume) is my problem.  Going to look over the "firewall forward" part and see what I can come up with first.

[Anticept]

Mix in some cooler cabin air and implement a thermostat system that will cut the fan off if it gets too hot.

[FredG]

Garrett, when you inspect forward of the firewall, look to see that the flat metal flapper in the "thermic choke" (FD terminology) moves fully to the heat position when the heat knob is pulled in the cabin.  The "thermic choke" is an aluminum box about 3" each side.  A duct from the shroud around the muffler (for carrying heated air) enters the box and a duct exits the box and enters the cabin.  The heat control knob on the panel has a cable that controls the position of the flat metal flapper in the box.  when the heat is off, the flapper obstructs the flow of hot air.  When the heat is on, the metal plate does not obstruct the flow of air (it simply pivots out the way) allowing it continue flowing into the duct that enters the cabin.  Due to the construction of this air flow control, you can actually see the flap position.

When I first started flying my 2006 CTsw, it was cold in the winter.  When I inspected the hot air control unit I saw that the flap would not move to the position that allowed full flow of heated air.  When that was fixed, I had much better heat.

I do not know if the CTls has the same parts for controlling the flow of heated air.  Tom, Corey, or Roger will know.

Finally, for all CT pilots, remember that the tighter we make the cabin, the more at risk we become of CO toxicity should we have a leak in the muffler (allowing exhaust to be mixed with warm air that enters the cabin) when using the heater.  I use a digital CO meter with an alarm rather than the color changing disk that came with the airplane.  

[Garrett Gee]

On 1/28/2023 at 7:47 PM, FredG said:

Garrett, when you inspect forward of the firewall, look to see that the flat metal flapper in the "thermic choke" (FD terminology) moves fully to the heat position when the heat knob is pulled in the cabin.  The "thermic choke" is an aluminum box about 3" each side.  A duct from the shroud around the muffler (for carrying heated air) enters the box and a duct exits the box and enters the cabin.  The heat control knob on the panel has a cable that controls the position of the flat metal flapper in the box.  when the heat is off, the flapper obstructs the flow of hot air.  When the heat is on, the metal plate does not obstruct the flow of air (it simply pivots out the way) allowing it continue flowing into the duct that enters the cabin.  Due to the construction of this air flow control, you can actually see the flap position.

When I first started flying my 2006 CTsw, it was cold in the winter.  When I inspected the hot air control unit I saw that the flap would not move to the position that allowed full flow of heated air.  When that was fixed, I had much better heat.

I do not know if the CTls has the same parts for controlling the flow of heated air.  Tom, Corey, or Roger will know.

Finally, for all CT pilots, remember that the tighter we make the cabin, the more at risk we become of CO toxicity should we have a leak in the muffler (allowing exhaust to be mixed with warm air that enters the cabin) when using the heater.  I use a digital CO meter with an alarm rather than the color changing disk that came with the airplane.  

Thank you for the tip.  We actually did look at the valve last annual (October) and found the spring was stretched out and replaced it.  We also looked at the full movement of the control arm, but I don't think we actually looked at the valve to see if it was fully moving.  What do you use for the digital CO detector?  Any suggestions.  I have been thinking about getting one, as I have a bad tendency of not including that in my scan.  I think a digital one would be much better, especially if it alerted audibly or with a flashing light.

[FredG]

I use a BW Clip Real Time 2 Year CO Detector 25-100 ppm (BWC2R-M25100).  It has a digital readout and an alarm (sound, vibration, and flashing light) at 25ppm (they are used widely in industry).  I use it because I am familiar with the unit from my work (I do occupational safety and health).  There are quite a few new digital detectors made specifically for aviation and some may be more economical than the BW unit.  A big drawback of the BW unit is that it has a two year lifespan which cannot be extended.  I think some of the new detectors have longer lifespans and replaceable batteries.  Unfortunately, I am not familiar with any of the newer detectors.

 

[Jim Meade]

Aviation Consumer had a review of CO detectors in their a  recent issue.

[Chuck]

It seems like a lot of new aviation products are including CO monitors as add-on features.  I know some of the new high-end headsets have them (Bose or Lightspeed).  I just bought a Sentry to work with my iPad running foreflight.  It gives me a backup AHRS, ADSB-in functionality to show traffic on the iPad, and also has a built-in CO monitor with alarm.

[PhilT]

On 1/31/2023 at 5:21 AM, garrettgee2001 said:

Thank you for the tip.  We actually did look at the valve last annual (October) and found the spring was stretched out and replaced it.  We also looked at the full movement of the control arm, but I don't think we actually looked at the valve to see if it was fully moving.  What do you use for the digital CO detector?  Any suggestions.  I have been thinking about getting one, as I have a bad tendency of not including that in my scan.  I think a digital one would be much better, especially if it alerted audibly or with a flashing light.

Hey Garrett, one more thing to check I believe (and I'm very new at these CTs so take it for what it's worth) is the inlet hole in the cowling to the inlet to the exhaust heater muff. The rubber that is supposed to seal this transition is broken so air can bypass easily instead of pushing into the heater muff. I have yet to change mine but hoping that will make a difference as well. 

Any comments on this Roger ?

[Garrett Gee]

7 hours ago, PhilT said:

Hey Garrett, one more thing to check I believe (and I'm very new at these CTs so take it for what it's worth) is the inlet hole in the cowling to the inlet to the exhaust heater muff. The rubber that is supposed to seal this transition is broken so air can bypass easily instead of pushing into the heater muff. I have yet to change mine but hoping that will make a difference as well. 

Any comments on this Roger ?

Thank you for that.  I did replace my a few years ago, but FD at the time didn't have any of the material in stock, so I used some baffle seal.  I think that is essentially what is there.  I do need to revisit that though and see how it is holding up.  It is possible my "fix" made it worse.

[PhilT]

On 3/9/2023 at 7:28 PM, garrettgee2001 said:

Thank you for that.  I did replace my a few years ago, but FD at the time didn't have any of the material in stock, so I used some baffle seal.  I think that is essentially what is there.  I do need to revisit that though and see how it is holding up.  It is possible my "fix" made it worse.

Hi again Garrett. 

Just got the plane back from the shop. They replaced the rubber at the cowling interface for me and it's really solid material. It's no longer hardcore winter here but I did see temps of -12C flying home and I only have to add about 40% heat and I'm really comfortable. 

That and taping off holes in the ceiling of the cabin really seems to have done the job.

(A thought occurred to me.. before the cowling fix, I wonder how much carb heat I was actually able to get with air simply bypassing that exhaust muff inlet? So hard to tell with these Rotax engines as the carbs self adjust? Does anyone else notice an RPM drop at all when applying carb heat?)

Phil

[Roger Lee]

If you seal up the cabin like we did in out CTSW's I could fly in single digits with just a shirt and Levis on. No jacket. People just don't do a good job sealing the cabin.  The door jam needs to be sealed and ALL holes up around your head need to be sealed. The air intake for the heat air should be properly aligned too.

[Tom Baker]

6 hours ago, PhilT said:

(A thought occurred to me.. before the cowling fix, I wonder how much carb heat I was actually able to get with air simply bypassing that exhaust muff inlet? So hard to tell with these Rotax engines as the carbs self adjust? Does anyone else notice an RPM drop at all when applying carb heat?)

The CTSW doesn't pull carb heat air from around the heat muff. The airbox is just open to the inside of the engine compartment. You will not see a drop in RPM for the CTSW. The CTLS does pull air from around the heat muff, and with it you will see a little drop most of the time.

[Garrett Gee]

7 hours ago, PhilT said:

Hi again Garrett. 

Just got the plane back from the shop. They replaced the rubber at the cowling interface for me and it's really solid material. It's no longer hardcore winter here but I did see temps of -12C flying home and I only have to add about 40% heat and I'm really comfortable. 

That and taping off holes in the ceiling of the cabin really seems to have done the job.

(A thought occurred to me.. before the cowling fix, I wonder how much carb heat I was actually able to get with air simply bypassing that exhaust muff inlet? So hard to tell with these Rotax engines as the carbs self adjust? Does anyone else notice an RPM drop at all when applying carb heat?)

Phil

I did replace the rubber at the cowling with some good baffle seal a couple years ago.  I do need to seal up the overhead holes.  I typically have them covered, but in the summer, I do uncover them.  I did seal up the doors when I got the plane a several years ago, but haven't checked that lately.  That might be a point of leakage.

[Garrett Gee]

1 hour ago, Tom Baker said:

The CTSW doesn't pull carb heat air from around the heat muff. The airbox is just open to the inside of the engine compartment. You will not see a drop in RPM for the CTSW. The CTLS does pull air from around the heat muff, and with it you will see a little drop most of the time.

I actually tested (just to make sure it was working) and saw about 80 RPM drop in cruise.

[PhilT]

4 hours ago, Tom Baker said:

The CTSW doesn't pull carb heat air from around the heat muff. The airbox is just open to the inside of the engine compartment. You will not see a drop in RPM for the CTSW. The CTLS does pull air from around the heat muff, and with it you will see a little drop most of the time.

I did not know that Tom.

Strange still that there is no drop in RPM upon use of carb heat? Is it because it's not as hot compared to muff produced heat?

[PhilT]

3 hours ago, garrettgee2001 said:

I actually tested (just to make sure it was working) and saw about 80 RPM drop in cruise.

Is yours a CTSW or CTLS?

[Garrett Gee]

9 hours ago, PhilT said:

Is yours a CTSW or CTLS?

CTLS

[Tom Baker]

14 hours ago, garrettgee2001 said:

I did replace the rubber at the cowling with some good baffle seal a couple years ago.  I do need to seal up the overhead holes.  I typically have them covered, but in the summer, I do uncover them.  I did seal up the doors when I got the plane a several years ago, but haven't checked that lately.  That might be a point of leakage.

There is an area of high pressure where the flap rods exit the fuselage. This allows cold air into the cabin side openings, and also on top of the overhead cover above the hat shelves on the CTLS. You will get some cold air blowing in around the edge of that cover. Also the cover is very thin, so it will radiate cold into the cabin. There is not much that can be done with the radiated cold. The only wat to stop it would be to design a boot to stop the airflow around the flap rod.

[PhilT]

2 hours ago, Tom Baker said:

There is an area of high pressure where the flap rods exit the fuselage. This allows cold air into the cabin side openings, and also on top of the overhead cover above the hat shelves on the CTLS. You will get some cold air blowing in around the edge of that cover. Also the cover is very thin, so it will radiate cold into the cabin. There is not much that can be done with the radiated cold. The only wat to stop it would be to design a boot to stop the airflow around the flap rod.

When the weather warms up I'm going to take a good close look at all of this and see what I can do to improve it before next season's -30C weather