Alaska is back to being cold again basically state wide. Its a balmy -12 here at my house in Kenai. The state low at the moment is in Huslia.
-51 at the moment. The density altitude there is a crazy -8514' !
Brrrrrdiigggiiiitttyyyy

Temperatures that low don't even compute in my reality. I don't think I've ever been in colder than -10 F.

If a guy was stupid enough to roll his little Lycoming powered airplane out of his heated hangar, fire it up, and go flying in those temps (-51 F), would he have mixture issues? What is the DA where full rich isn't rich enough?

It’s -11, wind 16 mph at 320, wind chill -36. Wind speed is supposed to pick up to 30-40 mph. If I were sure the wind direction wasn’t going to change...I’d be pulling the Pacer out of the warm Hanger to make a speed run to Dillingham and back. My cut off temperature is -25 and a crosswind greater than 15 mph.... runway is 32-14... wish we still had our crosswind runway..


Sent from my iPad using Tapatalk

Is there any danger from the engine making much more than rated power due to the low DA?

It's effectively like the NA engine is supercharged.

The coldest it gets here is typically 20's although it can get colder for brief periods.

I love flying my lowly O-360 in low DA. I get to see what it feels like to fly a big balls (235-260 HP) Maule.

Zzz wrote:Temperatures that low don't even compute in my reality. I don't think I've ever been in colder than -10 F.

If a guy was stupid enough to roll his little Lycoming powered airplane out of his heated hangar, fire it up, and go flying in those temps (-51 F), would he have mixture issues? What is the DA where full rich isn't rich enough?

That's what carb heat is for.

Gump

Zzz wrote:If a guy was stupid enough to roll his little Lycoming powered airplane out of his heated hangar, fire it up, and go flying in those temps (-51 F), would he have mixture issues? What is the DA where full rich isn't rich enough?

I've been wondering that very same thing lately. I always lean the mixture a bit here for takeoff (4160' MSL). I would tend to think anything below maybe a -2000' DA might require more fuel than a carb is usually set up for, but I have no idea, really. Wouldn't surprise me if carbs in those types of climates get jetted a bit differently.

Sure would love to feel how the plane flies though!

GumpAir wrote:

Zzz wrote:Temperatures that low don't even compute in my reality. I don't think I've ever been in colder than -10 F.

If a guy was stupid enough to roll his little Lycoming powered airplane out of his heated hangar, fire it up, and go flying in those temps (-51 F), would he have mixture issues? What is the DA where full rich isn't rich enough?

That's what carb heat is for.

Gump

Guess that makes sense

Our temp cut-offs were most places -30 for piston and -35 for turbine, but.....

There's always an inversion layer 1000 feet up or so where the temps might be 0 to ten above. So, even most cold days, we flew. Just gotta slow down and plan waaaaaay ahead to keep engine temps in the green, and the biggy for me was always nosewheel tires. They don't flex at -40, and when you turn off the runway onto a ramp, POP, the tire rolls off the rim and takes out the valve stem on the tube. In the Sleds I learned to wheelie real well, and could spend an entire flying day with the nosewheel never touching the ground unless I was at a complete stop.


Gump

Zzz wrote:Temperatures that low don't even compute in my reality. I don't think I've ever been in colder than -10 F.

If a guy was stupid enough to roll his little Lycoming powered airplane out of his heated hangar, fire it up, and go flying in those temps (-51 F), would he have mixture issues? What is the DA where full rich isn't rich enough?

Heated Hangar? Now, that’s funny right there!

Our cold cutoff for flying piston a/c was -40. One November, I’d been flying a borrowed Super Cub (stock everything, including no heat heater) on a moose survey north of Galena, AK for a little over a week. We ran this survey out of a wall tent camp on the north fork of the Huslia River, and temps had been running around the mid -20s early in the week, getting progressively colder each day....as I finished the last unit and landed back in Galena, the Metar was giving -35 there.

Happily took a hot shower and a night in a real bed in a warm building, I figured on heading home to Fairbanks next morning before the real cold settled in.

Next morning, Metar was reporting -40. Lovely, but “legal”. An observer for the moose count was also from FAI, and we were both ready to go home.

The cub (on skis) was parked on Alexander Lake, in the middle of town, which is a sump of sorts, maybe fifty feet or so below the Airport and town elevation. An agency House was on the lake, so we could plug in there.

We drove to the lake went down the stairs and started getting the plane ready to go....crap it was cold, and dark.

Got covers off and the POS engine cover wouldn’t bundle up enough to go in baggage-Stock baggage, recall. So, my passenger got in back and I shoved the cover in on top of him. Cozy.

Fired up the engine, let it warm a bit, though at these temps, running at idle is more of a “cooling off” gig rather than a “warming” one.

I pushed up the power, taxied to the end, turned around and once again listened to the Metar. -41. I’m going now, so switched to Airport freq. announced and push up power enough to get airborne and clear the power line at the end.

As I turn east, I go to company freq and let them know I’m up. The gent who lives on the lake comes back with “safe flight”, and “I just checked the NWS official thermometer on the lake shore and it’s reading an even -60 F”. Okay, my excuse is I didn’t know there was actually a thermometer on the lake, but I’m NOT going back.

I figure it’ll be much warmer at altitude, so I climb up to 4000 feet, and indeed it’s warmer......but the gps ground speed dropped from about ninetieish to fortyish.....and with stock tanks and short days, we’re not getting to FAI today at that rate. Sooo, back down to NOTE heights, where there is less wind, and a lot less warmth.

An hour and a half or so later, we’re passing Tanana. I asked my back seater if he wanted a pee break and he answered in the affirmative. So I called Tanana FSS and told them we were inbound. He responded with “Tanana weather is sky partially obscured, 500 indefinite, visibility 3 miles in haze, wind calm, temperature -58 F.”

From the back seat comes “I don’t need to pee.” Me neither, so I call and let them know we’re continuing to FAI.

That flight was ~ three hours and change. I spent the entire flight trying to keep a small hole open in the frosted windscreen.

FAI was giving a balmy -35 when we arrived.

That little engine plugged along like it was born for this kind of shit. I never pushed the go lever all the way forward, but didn’t need to.

Mountain Doctor,

The Cessna 185s I flew recommended that the cold weather kit be installed for temps colder than.....around 0 F. I learned real quick not to install the plates that cover most of the cooling air inlets, but the other part of that kit is an engine induction restrictor plate that is mandatory at cold temps. The induction has an “alternate air door” inside the lower cowl. It’s designed to open against spring pressure if the air inlet is blocked by ice, thus inducting warm air from the lower cowl. With the restrictive plate in place, the engine draws enough air at full lope to open that door, this warming the air going into the engine, and preventing a serious overboost.

You can do the same by just not going crazy with throttle, but.....

And, of course, the oil cooler (non congealing type) was always covered with duct tape.

Those things make buckets of power in cold in any case.

MTV

mtv wrote:

Zzz wrote:T
If a guy was stupid enough to roll his little Lycoming powered airplane out of his heated hangar, fire it up, and go flying in those temps (-51 F), would he have mixture issues? What is the DA where full rich isn't rich enough?

Heated Hangar? Now, that’s funny right there!

I just wanted to take the pre-heat/frozen oil element out of the picture and talk about stoichiometry.

Ya'll poor bastards with your hangar shortages up there...

mtv wrote:

Zzz wrote:Temperatures that low don't even compute in my reality. I don't think I've ever been in colder than -10 F.

If a guy was stupid enough to roll his little Lycoming powered airplane out of his heated hangar, fire it up, and go flying in those temps (-51 F), would he have mixture issues? What is the DA where full rich isn't rich enough?

Heated Hangar? Now, that’s funny right there!

Our cold cutoff for flying piston a/c was -40. One November, I’d been flying a borrowed Super Cub (stock everything, including no heat heater) on a moose survey north of Galena, AK for a little over a week. We ran this survey out of a wall tent camp on the north fork of the Huslia River, and temps had been running around the mid -20s early in the week, getting progressively colder each day....as I finished the last unit and landed back in Galena, the Metar was giving -35 there.

Happily took a hot shower and a night in a real bed in a warm building, I figured on heading home to Fairbanks next morning before the real cold settled in.

Next morning, Metar was reporting -40. Lovely, but “legal”. An observer for the moose count was also from FAI, and we were both ready to go home.

The cub (on skis) was parked on Alexander Lake, in the middle of town, which is a sump of sorts, maybe fifty feet or so below the Airport and town elevation. An agency House was on the lake, so we could plug in there.

We drove to the lake went down the stairs and started getting the plane ready to go....crap it was cold, and dark.

Got covers off and the POS engine cover wouldn’t bundle up enough to go in baggage-Stock baggage, recall. So, my passenger got in back and I shoved the cover in on top of him. Cozy.

Fired up the engine, let it warm a bit, though at these temps, running at idle is more of a “cooling off” gig rather than a “warming” one.

I pushed up the power, taxied to the end, turned around and once again listened to the Metar. -41. I’m going now, so switched to Airport freq. announced and push up power enough to get airborne and clear the power line at the end.

As I turn east, I go to company freq and let them know I’m up. The gent who lives on the lake comes back with “safe flight”, and “I just checked the NWS official thermometer on the lake shore and it’s reading an even -60 F”. Okay, my excuse is I didn’t know there was actually a thermometer on the lake, but I’m NOT going back.

I figure it’ll be much warmer at altitude, so I climb up to 4000 feet, and indeed it’s warmer......but the gps ground speed dropped from about ninetieish to fortyish.....and with stock tanks and short days, we’re not getting to FAI today at that rate. Sooo, back down to NOTE heights, where there is less wind, and a lot less warmth.

An hour and a half or so later, we’re passing Tanana. I asked my back seater if he wanted a pee break and he answered in the affirmative. So I called Tanana FSS and told them we were inbound. He responded with “Tanana weather is sky partially obscured, 500 indefinite, visibility 3 miles in haze, wind calm, temperature -58 F.”

From the back seat comes “I don’t need to pee.” Me neither, so I call and let them know we’re continuing to FAI.

That flight was ~ three hours and change. I spent the entire flight trying to keep a small hole open in the frosted windscreen.

FAI was giving a balmy -35 when we arrived.

That little engine plugged along like it was born for this kind of shit. I never pushed the go lever all the way forward, but didn’t need to.

Mountain Doctor,

The Cessna 185s I flew recommended that the cold weather kit be installed for temps colder than.....around 0 F. I learned real quick not to install the plates that cover most of the cooling air inlets, but the other part of that kit is an engine induction restrictor plate that is mandatory at cold temps. The induction has an “alternate air door” inside the lower cowl. It’s designed to open against spring pressure if the air inlet is blocked by ice, thus inducting warm air from the lower cowl. With the restrictive plate in place, the engine draws enough air at full lope to open that door, this warming the air going into the engine, and preventing a serious overboost.

You can do the same by just not going crazy with throttle, but.....

And, of course, the oil cooler (non congealing type) was always covered with duct tape.

Those things make buckets of power in cold in any case.

MTV

Thanks for the input.

Since the carb can only get so rich at full rich mixture, it seems to me running with carb heat on would richen it up some and make it more stoiciometric. Of course then you have unfiltered air, but once off the ground that shouldn't matter.

Yeah, unfiltered air is a non issue in winter in the interior of AK. There is no dust there in winter. Nothing out there but snow, and that won't hurt a thing unless you somehow shove chunks of it down the induction.....

MTV

When I was learning to fly out of Elmendorf AFB, we had a heated hangar that all of the Aeroclub airplanes were kept in, but that didn't make it warmer to fly. Some Alaskans like to call the Anchorage area the "banana belt", but it still can get pretty cold. The coldest I remember flying in during training was about -20F. Carb heat made all the difference in getting the little Continentals to run smoothly in that cold of temps. They didn't have CHT gauges, but often the oil temp gauges would just barely get into the green.

That, incidentally, was my introduction to carb ice, too. I was on short final to 34 at Merrill Field when the engine quit--prop stopped about 50' in the air. Fortunately my instructor had the philosophy that most landings should be without power, so I had enough altitude to continue to land--but it was embarrassing, as I didn't have enough speed to coast off the runway--stopped still on the runway at taxiway F, which is about halfway down the runway. As always, Merrill was busy, so at least half a dozen airplanes had to go around before I was able to pull the airplane off the runway. By that time, the ice had melted, and it started up again without any difficulty.

Then I moved back to Laramie. There had been days when I was in college at UW when the temps in Laramie hit as low as -54F, and it wasn't unusual to see -30--35F. So when the first winter after returning to Laramie rolled around, and I was regularly working on my commercial, I often flew in temps well below zero. That cold weather "l'arnin'" I'd had in Anchorage paid off, because many of the other regular renters/students didn't want to fly in that cold of weather, so I'd be the only one. I seem to recall that all the 172s at Laramie had cold weather kits installed, which blocked off part of the cooling air intakes.

Now I've become a wimp. My airplane has a pretty good heater, but I really don't want to fly when it's all that cold. Last winter returning from visiting my Sis in Durango, I encountered temps at altitude that were well below zero. Ol' Molly dog and I were both ready for it, with her wearing her down vest (one of my cast off Eddie Bauer vests that my belly has outgrown) and me wearing both a down vest and a heavy coat, and the heater going full, so we were comfortable although the OAT briefly said -40F over the San Luis Valley. So this winter I don't think I've flown in anything colder than +15F on the ground, which meant a few degrees colder just flitting about at around 6500' or 7500' MSL.

I can appreciate those whose employment requires flying in really cold temperatures, but honestly I'm glad that I'm not required to do that. I love the extra performance of cold weather flying, but beyond that, I'd much rather be warm.

Cary

One of the really “interesting” phenomena you find in Interior Alaska, and elsewhere in extreme cold, is the hard inversions, noted earlier by Gump, and intimated by me in the previous story.

My last home in Fairbanks was ~ 150 or 200 feet above the valley floor. When the temperature in town was -40, it would rarely be below -20 at the House. So, as Gump noted, a smart pilot flying in very cold will commonly find much warmer temperatures at even as little as a thousand feet agl.

BUT, as they say, you can’t stay up there forever...... at some point you’ll have to descend and if that isn’t somewhere a lot warmer, you’re going to wind up back in those very cold temps.

Further, these hard inversions can take on micro characteristics......I once landed at a seismic camp on a large lake about 25 miles SW of Fort Yukon. FYU was reporting -19 F at the time, but the NWS certified thermometer at the camp read -58 on the lake surface......just a few feet lower than FYU, but down in the trees, protected from the very light breeze at the Fort.

So, if you’re up for flying in these extreme temps, bear in mind that if anything goes wrong with your magic carpet, you’ll probably be landing in one of those “cold sumps”.

I was pretty brave (and seriously dumb) when I started flying in the interior. Over the years, I became more circumspect about flying in very cold temps. But, there was work to do and working north from FAI, if you don’t fly at cold temps, you won’t get much done in winter.

Be careful out there.....those fire making skills need to be sharp.....

MTV

That is an incredible DA! Can't even imagine...

Carb heat would be a lifesave is my guess. Fuel really starts to atomize poorly in really cold temps, especially in a carb'd engine. Being able to richen it up, and help atomization would make a lot of difference.... once you get some heat built up and the carb heat is working! Crazy cold temps.. I saw -22f here once on new years eve... plenty cold for me.

mtv wrote:One of the really “interesting” phenomena you find in Interior Alaska, and elsewhere in extreme cold, is the hard inversions, noted earlier by Gump, and intimated by me in the previous story.

My last home in Fairbanks was ~ 150 or 200 feet above the valley floor. When the temperature in town was -40, it would rarely be below -20 at the House. So, as Gump noted, a smart pilot flying in very cold will commonly find much warmer temperatures at even as little as a thousand feet agl.

I know what you mean, we lived on Chena Ridge. Once my diesel truck cranked and ran just fine at the house but gelled up on Chena Pump. I had to get towed.

It had been sitting for a few months and I guess I still had some summer fuel in it.

Back in 75 or so I was working on the ice off Ellef Ringnes Island in the Arctic. A hercules dropped off a Nodwell on our ice strip. Dead calm, minus 40 and severe clear. Looked like he was off in 500 hundred feet and climbing at 60 degrees. Very impressive.

mtv wrote:Yeah, unfiltered air is a non issue in winter in the interior of AK. There is no dust there in winter. Nothing out there but snow, and that won't hurt a thing unless you somehow shove chunks of it down the induction.....

MTV

Unless you are in Bethel, Dust, dirt and snow always blowing around in the winter.

We have snow in Platinum...a little bit...but its brown.


Sent from my iPad using Tapatalk

The snow in that area doesn't melt, it wears out from being blown a hundred miles and then the next day blown back the opposite direction and so on.