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What is the coldest temperature you've flown in?

eh_v8_tor

Active Member
Hi Folks,

I 'm thinking about fuel system design with regard to the extreme cold weather that we get up here in Canada.

We are obliged to use a gascolator here. I've been wondering if anyone is using a gascolator placed inside the cabin, after the fuel selector, but before the high pressure boost pump. I'm planning to use fuel injection on some type of IO-360.

How cold is the coldest you've flown in? Please describe your fuel system with regard to the placement of any screens, gascolators and carb vs. fuel injection.

Steve Wolfe

P.S. Cold wx flying is mostly misery anyways, but I would like to be capable of it if a bout of insanity grips me in February!
 
I've flown Cherokees at -15 F many times in WI, MN, and IA. I think the coldest was -20 F. That was on the ground, of course.

Cherokees have gascolators. I remember it being so cold that there was ice around it, after sumping.

I look back at flying in the upper Midwest, in winter, and shake my head in wonder that I ever did it.
 
Cold wx

I've flown Cherokees at -15 F many times in WI, MN, and IA. I think the coldest was -20 F. That was on the ground, of course.

Cherokees have gascolators. I remember it being so cold that there was ice around it, after sumping.

I look back at flying in the upper Midwest, in winter, and shake my head in wonder that I ever did it.


Hi Jay,

I've not flown a cherokee, but I assume that the gascolator is on the hot side of the firewall similar to the Cessna way of doing things. Is that correct!

Steve
 
Hi Jay,

I've not flown a cherokee, but I assume that the gascolator is on the hot side of the firewall similar to the Cessna way of doing things. Is that correct!

Steve

Yep. The location varies somewhat from model to model, but it's always on the hot side of the firewall.
 
Yep. The location varies somewhat from model to model, but it's always on the hot side of the firewall.

Well, now that I think of it, that's not true. The main gascolator on my Cherokee Pathfinder was in the belly of the plane, far from the engine. It was a giant pain in the butt to "pee" all four tanks on the plane with a lever in the back seat.
 
The temperature of the gasoline is not the important issue, it won't freeze in normal temperatures. It is the problem of keeping the engine warm and the oil hot. At -40 the gas will still flow well but you will be able to do chin ups on the prop. You will need to pre heat your engine and have a warm battery. Don't use a propane heater they produce too much moisture and will cause a lot of ice to build up on a cold engine. Minus 35F is the coldest I have flown in and it was not pleasant in the cabin at all.
 
Also at very cold temperatures you won't need to sump your tanks, the water will be frozen if there is any at all.
 
Cold temps

Also at very cold temperatures you won't need to sump your tanks, the water will be frozen if there is any at all.

Hi Norman,

I think the likely scenario would be if I were to pull the plane out of a toasty warm hanger into cold weather. One could even see colder temperatures at the chosen cruising altitude. As you can imagine this is a situation where condensation could occur in the fuel tanks. The condensation then could turn to ice clumps or crystals that could potentially clog up fuel filter or gascolator screens.

I think avgas freezes at around -60 degrees Celcius. The issue is not the fuel, but the water that is suspended in the fuel, freezing up and clogging things up.

My biggest question is really this. Has anyone operated with a gascolator mounted on the cooler side of the firewall ?? ....and if so, how cold is the coldest temperature you've flown it in?? .....but I am also interested in the coldest temperatures in general that people fly in. A description of the placement of the filters or gascolators would be required for comparing apples to apples.

Thanks,

Steve W.
 
Stick to the plans

Hi Steve,
If gascolator is required I would suggest to mount it exactly per plans. I doubt there is better location.
I don't keep track of cold temperatures I am flying my RV but during this brutal winter I put around 70 hours on the plane in January/February. A lot of Maine, NH and Upstate NY flying. Norman is right saying
The temperature of the gasoline is not the important issue, it won't freeze in normal temperatures. It is the problem of keeping the engine warm and the oil hot. At -40 the gas will still flow well but you will be able to do chin ups on the prop. You will need to pre heat your engine and have a warm battery.
Flying in the cold is a challenge but it's fun. All skies and airports are yours because everybody sits home even on a sunny weekend.

I have carbed O-320 without priming system. My gascolator is mounted on the firewall per Vans drawing.
 
Cold weather

Hi Steve,
If gascolator is required I would suggest to mount it exactly per plans. I doubt there is better location.
I don't keep track of cold temperatures I am flying my RV but during this brutal winter I put around 70 hours on the plane in January/February. A lot of Maine, NH and Upstate NY flying. Norman is right saying Flying in the cold is a challenge but it's fun. All skies and airports are yours because everybody sits home even on a sunny weekend.

I have crabbed O-320 without priming system. My gascolator is mounted on the firewall per Vans drawing.

Hi Vlad,

I saw your plane at the Stanley fly-in, too bad we didn't get a chance to meet in person.

Here is the thing. I'm using fuel injection so I have a high pressure boost pump. The pump manufacturer insists that there should be a filter before the pump to prevent any debris from getting in there and destroying the pump. I don't care so much about that, however I am quite concerned that debris (just regular old dirt and crud) could eventually clog the boost pump and it's bypass. (I have an Andair pump).

I know of a reputable repeat offender who put his gascolator in the position that I described earlier in this thread. (His gascolator is inside the cabin prior to the boost pump). This would catch anything that could potentially make a blockage in the pump/ bypass it's self. .....including frozen H2O contaminants. This could ALSO cause a blockage.

On the other side of the coin. He is from the sunny south part of Canada. I don't know if he's operated in the -40 degree weather that we regularly see out west during our winter.

Would the cabin area be hot enough to heat the gascolator .... enough to turn the H2O into liquid??? I wouldn't want ice cubes to block the filter in the gascolator. Remember that the cabin is warm, but the fuel from the tanks could be close to -40 degrees flowing through there.

If the cabin is hot enough, then this is the perfect place for it.

If it's not, then it should be on the firewall where it would be much warmer than in the cabin. In this case, the fuel lines should be taken apart at least at each annual inspection to be sure that there is no debris trying to clog the pump/ bypass.

Steve
 
Cold weather / gascolator position

Is there anyone who is flying with the gascolators in the wing root, or anywhere other than on the hot side of the firewall?

What's the coldest weather you've flown in? Have you had any fuel flow issues?

Steve
 
huh ???

I have andair gasolators in each wing root... the filter area is huge, formed up much like an oil filter... not sure just what failure mode you are envisioning. I have flown in the cold but nothing crazy... 15 F on the ground, 0 F in the air.
 
Cold wx / fuel system

I have andair gasolators in each wing root... the filter area is huge, formed up much like an oil filter... not sure just what failure mode you are envisioning. I have flown in the cold but nothing crazy... 15 F on the ground, 0 F in the air.

Hi Stephen,

I'm envisioning taking my plane from a relatively warm hanger out into the extreme cold. Condensation could form and turn to ice which could plug screens. I'm thinking of going from + 75 Fahrenheit to - 40 or -45 degrees at the cruising altitude.

This could be typical if you were crossing Manitoba and Saskatchewan during the coldest days of winter on a long cross country flight. If at altitude for several hours, the fuel could become very cold....in turn freezing any water or condensation that is in the tanks. Ice crystals can form and plug up screens.

I'll admit that this is extreme circumstances, but I wouldn't want to be afraid to go fly just because it's really cold outside. I could very well be doing this very thing.

We've seen many days this past winter where you could take a boiling pot of water outside and throw it up in the air. It comes back down to the ground as snow!!

Steve

p.s. You have a good point that the gascolators have a large filter area. With fairly clean fuel it wouldn't be any problem.... The question is " how much ice could they filter before blocking the screens"?
Ice will only accumulate more and more if the gascolator is in a location that is too cold to melt the contaminate and allow it to be liquid in the bottom of the sediment bowl.
 
If you are keeping your plane in a nice warm hanger sump the tanks before taking it out of the hanger, there wont be any ice to worry about. I don't think that you will be able to keep your engine warm at -40. I also don't think that the water will thaw out going through your filter at those temps. You certainly won't be warm in the cabin at those temp unless youmaremflying with a snow mobile suit, warm article boots, hat and mitts. On your return trip how are you going to get the engine warm enough to start?
 
If you are keeping your plane in a nice warm hanger sump the tanks before taking it out of the hanger, there wont be any ice to worry about. I don't think that you will be able to keep your engine warm at -40. I also don't think that the water will thaw out going through your filter at those temps. You certainly won't be warm in the cabin at those temp unless youmaremflying with a snow mobile suit, warm article boots, hat and mitts. On your return trip how are you going to get the engine warm enough to start?
Hey Norman,

Yep it could be cold in the cabin.

Starting would certainly be a problem unless I pushed through to Vancouver or found a heated hanger to rent overnight.

One mod that I plan to do is to make up some stick boots for the wing/fuselage intersection. They would be like a stick boot inside the cabin, but they would cover the large aileron push tubes. This should keep cold draughts from entering the fuselage through the wing roots, and cut down on the heat required from the heater muff.

Steve
 
I've flown as crew in a large USAF helicopter during cold-weather testing in Alaska a long time ago. We operated between -20 F and -63 F, with lots below -40 F.

1. Oil freezes rapidly at those temps. If we didn't start up immediately after pushing out of the hangar, we'd have to go through the entire cold-start sequence.

2. Cabin heat is pretty much non-existent. The hardest things to keep warm were our feet, in contact with the aluminum floor. Bear in mind that we were dressed to survive outside in those conditions.

3. Headsets or warm heads were our two choices. Noise or cold. It was cold enough to choose noise.

4. Hydraulic fluid was in a gel-like consistency. While our hydraulics worked, they didn't work well in the colder temperatures. Don't count on your brakes working - or releasing if you use them.

5. A cold-soaked helicopter was a miserable thing to attempt to start, even with ground support equipment available. If we took it into a heated hangar, it would begin leaking from many orifices, even some that weren't intended to be orifices.

Dave
 
I don't remember exactly what the outside temp was but this past winter flying my -7 home to Georgia from California in snow, I reached back to grab our bottled water and the water inside the bottles was frozen... We decided it was time to land and call it a day.:eek:
 
Two AC.

1) O-320 E2D with a gascolator on the firewall in a cool box for summer heat protection. Flown as cold as -30 but only on a few long cross country flights. No issues with fuel flow or ice crystals in fuel. Non heated hangar at the time.

2) IO-540 Rocket flown numerous times in -18C to -20C but usually warmer at altitude. A mix of cold hangars, warm hangars and no hangar so lots of potential for condensation, as well as snow and rain contamination. The gascolator is mounted in the center between the foot wells , along with the boost pump. After the andair selector valve the fuel goes through the gascolator then the boost pump, then exits through the firewall and into the engine driven pump. No issues to date with water or ice in the fuel. I have never found any when sumping the wing tanks OR the gascolator.

However, on long cross country flights even in clear blue sky if the air temp and humidity is just right there is enough throttle body ice builds up to really get your attention when you reduce the throttle for landing and the ice breaks free. Just imagine a 540 trying to jump out of the cowl for a heartbeat. Then all is OK. It's enough to keep you high and close on the approach just in case you become a glider.

Since I started flying seaplanes, I sump for water in everything I fly in. A friend took me flying in his cherokee that was tied down outside. I refused to get in unless he sumped the wing tanks. It took 3 cycles with sampler to clear the right wing:eek: He was a bit red in the face.

On the Rocket and RV8 you have a good chance to look at your fuel vents when you sump the tanks for water.

Good luck in your build. -30 is a good time to stay at home with the girlfriend.
 
Is there anyone who is flying with the gascolators in the wing root, or anywhere other than on the hot side of the firewall?

What's the coldest weather you've flown in? Have you had any fuel flow issues?

Steve

My gascolator is in the left wing root area, and I?ve never had an issue during any of my winter flying. I?ve flown in ground temperatures down to -20?C or so. But my aircraft lives in an unheated hangar, and I usually add fuel post flight in the winter, so my experience isn?t completely relevant to your scenario.
 
a couple years ago leaving the northeast in the fall to head south we had to deal with 28 degrees. :D it was tough, cold start, frost on the plane, eek. made it out fine. ill pass on cold temps. take off performance was good though. hello florida.
 
25 below

I ferried an unheated Pitts S2B to Afton Wyoming around twenty years ago. The day I landed in Afton, Jackson Hole was reporting 25 below. It was probably colder at 12500 as I was crossing the mountains. Because the oil breather tube that goes to the tail in most aerobatic aircraft was unvented, I blew the seals on the engine and made a real mess. I'm not sure why I agreed to that flight at that time of year.
 
Yep. The location varies somewhat from model to model, but it's always on the hot side of the firewall.

In the Cherokee 140, the gascolator and electric boost pump are on the engine side of the firewall, BUT they are housed inside a metal box-like structure that seals them away from the engine heat plus that box is fed via a 2" SCAT duct to a forward-facing air scoop on the bottom of the lower cowl to force-feed ram air into the box to keep the gascolator and boost pump cool, to help mitigate chances of vapor lock. In extremely cold weather, it's going to get mighty chilly inside there ;)
 
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