It's cold!!

[Flymu2]

2000 M20S.

 

When the temp is below freezing I just don't get enough heat in the cabin even with the cabin heat pulled all the way out. Had a recent trip back from Willmar after tank reseal where OAT was -29C. There was barely enough heat. My feet were numb when I got out.

 

Causes? Cures?

 

Thanks,

 

Dennis Wolf

[orionflt]

My best recommendation is to tighten up air leaks. Made a big difference in my C.

[Awful_Charlie]

I really wish there was an easy and approved fix for this.  I've had a go at sealing up the leaks with the use of a plumbers smoke stick, a vacuum cleaner and a bunch of tape, but either there's a load I'm missing, or the heater just doesn't have the guts.

 

Such a shame when just forward of the firewall there is an abundance of heat, and highly capturable heat in the form of the oil cooler and turbo intercooler

[scottfromiowa]

They make electric and disposible feet warmers. Got to be a deer hunter (mentality)to fly in the winter. Adapt and improvise...on the cheap.

[WardHolbrook]

They make electric and disposible feet warmers. Got to be a deer hunter (mentality)to fly in the winter. Adapt and improvise...on the cheap.

I've still got the battery operated electric socks I bought 30 years ago when I first started flying gliders. 

 

I'd also check the obvious - cabin air leaks and make sure the cabin heat system is checked out, but at some point, the thermometer overpowers the heat muff. Wait until you've had the pleasure of flying a light twin in the upper midwest in the winter. At some point, guaranteed, the Janitrol heater is going to give up the ghost and you'll have one of the most miserable aviation experiences you can have. 

[mooniac58]

For what it is worth I have frozen feet in my Malibu Mirage this time of year in the FLs. No air leaks (pressure shell) but it is just hard to overcome all that cold around the aircraft.  The Mirage has an electric aux heater that helps (basically a hair dryer rigged into the defog blower that pulls 40A).  My instructor advised me on very cold days to place an electric heater in the cabin the night before.  He said that starting with the interior of the aircraft pre-warmed will help you from getting too far behind things...trying to warm up a cold soaked airplane is a harder battle.

 

Looking forward to warmer months for sure!

[BorealOne]

I put closed cell foam in the exterior cabin air vents during the winter. I figure if we can block our oil coolers, we should block our people coolers too. 

[aviatoreb]

My heater in my rocket is very good I think - I wear a light jacket (taking off the big jacket) even when it's -30f oat - but my feet still get cold - so I keep some thick leather wool booty slippers in the plane full time - they are clean and they live in the plane for winter ops. They do the job.

 

Here is a picture of the product I have - its sort of like leather gloves for your feet.  They are like sheep fur lined leather socks.  Sort of like an aviators sheep sheer lined jacket, but for your feet.  I like that they are close fitting since I always fly without shoes - I feel the pedal action better, and my big size 13 feet are sort of too big with big heavy winter shoes to fit well in the foot wells and feel what's going on.  I fly without shoes in the summer too - just my socks - I find I fly better feeling what is going on rather than reacting visually to what is going on. 

[Mooneyjet]

I flown my m20 c at -36 c and it had not too much problem keeping up with a 400 nm flight I did stay at about 6k. I also did start with a warm cabin. I may say that it climb like a home sick angel.

[carusoam]

LOP doesn't work in the winter....

Lower EGTs equate to lower heat transfer in the heater muff.

Flying at high altitudes has a similar effect. Less heat (less power) is generated by N/A engines at altitude.

There is very little insulation in the footwells. There are boots to help seal around the rudder pedals.

My old C had no insulation. It either fell out, or it was removed. check to see if you have some or replace what is no longer there.

Ideas that come to mind...

Best regards,

-a-

[Flymu2]

Wait until you've had the pleasure of flying a light twin in the upper midwest in the winter. At some point, guaranteed, the Janitrol heater is going to give up the ghost and you'll have one of the most miserable aviation experiences you can have. 

 

BTDT. I flew mail in BE18's out of Moline IL in the '70's.

[jlunseth]

Sorry, but no one can fix that for you.  The Mooney has a designed in air leak and there will be some exchange of air through the cabin.  You need to be very careful about installing "extra insulation" in the cabin, there are types of insulation that retain moisture and cause corrosion in the steel roll cage.  The heat comes out of the base of the center console, so really does not get forward very well to warm feet in the footwells.  The only way to beat it when temps are as cold as that (-20F) is to wear more clothes.  Especially warmer socks and shoes.  The cabin heater does a little better job heating your upper body.

 

I flew out to Willmar about the same time as you were coming back.  Temps were around -10F as I recall and I had not had my oil cooler block installed yet.  It was a balancing act to keep the oil temp above 100 (minimum operating temp) without running the engine right at peak.  Brian put a cooler block in for me and the trip back was much nicer for the engine, but my feet were still cold.

 

Two words.  Merino wool.

[WardHolbrook]

I guess the best thing to do is dress appropriately for the flight...

 

[jlunseth]

Yep.  That looks like the outfit I was wearing last week. 

[Flymu2]

I flew out to Willmar about the same time as you were coming back.  Temps were around -10F as I recall and I had not had my oil cooler block installed yet.  It was a balancing act to keep the oil temp above 100 (minimum operating temp) without running the engine right at peak.  Brian put a cooler block in for me and the trip back was much nicer for the engine, but my feet were still cold.

 

Two words.  Merino wool.

 

I ended up going to 11.5 to stay over some icy clouds. Temp was -29C OAT, putting density altitude at about 9500.

 

I turned around so that my feet were directly in front of the heat outlet, and even with that it was frigid. The heater output was just warm, not hot.

 

On balance though the plane performed great. With about a net 30 kt tailwind I made it from Willmar to Farmingdale (just under 1000 nm) in 5 hours flat burning 63 gal. There's nothing else in the sky that will do that.

 

Everything is a set of compromises.

[jlunseth]

You probably know this, but just to make sure, if you pull the cabin vent knob out when the cabin heat knob is also out, that mixes cold vent air in with the warmed air.  When it is supercold and you need all the heat you can get, the cabin vent knob should stay in.  If you had it out, that may have cooled the heating airstream.  There is also an internal adjustment the mechanic can make to moderate the amount of heating air coming in.  You might have them check that next time.  My heating air is usually nice and toasty once the engine warms up, it just does not warm the footwells very well, and when it is truly cold it does not warm the cabin enough to be flying in light clothes.

[Cruiser]

the heat output in the Ovation is great, yesterday's flight was at -10°C for about two hours. I had to close the heater vent to the first notch and the cabin was comfortable BUT my feet about froze.  I can see that it would be much worse at -20 or -30° temp.

[RJBrown]

If cowl flaps are open you can lose heat. You may need to check and see how closed they are.

[Shadrach]

Not sure when the change occured, but my 67F has two blast tubes with butterfly valves that port heat directly from the heater box that runs atop the nose gear wheelwell into the footwells. I insulated my plane with closed cell vinyl nitrided foam. I've never been cold in my plane even at sub zero temps in cruise. The back seaters can suffer from uneven heat distribution in such a way that if their feet are toasty, their torsos are getting cooked, but I've only ever had an issue with females. Someone needs to come up with an STC for a low profile blast tube to run under the carpet to the rear pax feet area.

There are vents to the outside just aft back of the horizontal rear seat cushion which probably help a little to draw cool air out of the cabin.

[aaronk25]

but I've only ever had an issue with females.

Ah slippery slope here my friend

[carusoam]

Aluminum rudder pedals make nice heat sinks...

Anyone try to insulate their surfaces?

Best regards,

-a-

[Hank]

What rubber compound do you recommend for insulation and non-slip properties? It must also be flame resistant, and not interfere with full-deflection crosswind landings.

[carusoam]

I prefer the Sperry docksiders. They provide for good feel on the rudder pedal. But very little insulation!

-a-

[kmyfm20s]

Buy some of those really nice UGG driving shoes, wool lined with rubber sole and heal wrap. Makes me wish I didn't live in San Diego for a day just so I could justify having a pair!

[bonal]

Planning a trip to Montana so my wife had me remove the rear seat and I had the STC install pot belly wood stove nice and toasty now