Cold Operation's?
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Senis Semper Fidelis
Joined: Feb 2001
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From: Lancashire U K
Cold Operation's?
Hi Rotorheads,
Last year I was in Finnish Lapland, the indicated day time air temp was fluctuating between -15 to -27 degrees of frost, there seemed little free moisture, but in the rays of the sun you could see a constant falling of crystals of very fine ice(which were so small that you could not feel them), I was amazed to come across a twin Squirril in a clearing and a guy clearing the frost of the inside screen, so with my son, I stood and watched as he(the pilot) cranked this machine into life, the thing that puzzeled me was the speed at which he accomplished all this and then took off, according to my watch it was just three and a half minutes from starting to crank, he lifted to about 150ft(towering type lift) and then flew of with what looked like a transistion from a low power take of, but remained at this low level. It turned out to be the state mapping department, who were mapping out the local terrain( we were about 200 miles inside the Artic Circle).
Could any of you cold flyers explain, what are the problems with flights in very cold area's and does low flying in such climates offer any advantage(apart from staying out of much colder air at higher altitude's) I also saw the Finnish Army Huey types(2 blades) flying at this sort of height also.
Last year I was in Finnish Lapland, the indicated day time air temp was fluctuating between -15 to -27 degrees of frost, there seemed little free moisture, but in the rays of the sun you could see a constant falling of crystals of very fine ice(which were so small that you could not feel them), I was amazed to come across a twin Squirril in a clearing and a guy clearing the frost of the inside screen, so with my son, I stood and watched as he(the pilot) cranked this machine into life, the thing that puzzeled me was the speed at which he accomplished all this and then took off, according to my watch it was just three and a half minutes from starting to crank, he lifted to about 150ft(towering type lift) and then flew of with what looked like a transistion from a low power take of, but remained at this low level. It turned out to be the state mapping department, who were mapping out the local terrain( we were about 200 miles inside the Artic Circle).
Could any of you cold flyers explain, what are the problems with flights in very cold area's and does low flying in such climates offer any advantage(apart from staying out of much colder air at higher altitude's) I also saw the Finnish Army Huey types(2 blades) flying at this sort of height also.
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From: Canada
Vfrpilot: I operate in a similar environement
and I can't think of 1 advantage of remaining at 150 feet unless it was a mission requirement .
Flying in ice crystals is not a problem as ice crystals don't stick.If it is that cold
(-27) the airmass is quite uniform in the lower levels and the temperature will probably remain constant for the first 3000 feet.
In fact because the atmosphere is heated and cooled by radiation from the earth, at night the temperature at ground level is colder than at 3000 feet , i.e. if you take-off at near dawn ( when temperatures are coldest) with a temperature of -27 a climb to 3000 feet will show an increase in temperature.
and I can't think of 1 advantage of remaining at 150 feet unless it was a mission requirement .
Flying in ice crystals is not a problem as ice crystals don't stick.If it is that cold
(-27) the airmass is quite uniform in the lower levels and the temperature will probably remain constant for the first 3000 feet.
In fact because the atmosphere is heated and cooled by radiation from the earth, at night the temperature at ground level is colder than at 3000 feet , i.e. if you take-off at near dawn ( when temperatures are coldest) with a temperature of -27 a climb to 3000 feet will show an increase in temperature.
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Senis Semper Fidelis
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From: Lancashire U K
Hi, IHL
Thank you for that explanation, but what about start up in these type of temps, by the way I envy you working in that sort of temp/enviro, whislt intense cold has its drawbacks I found it very nice to be in and work in!
Thank you for that explanation, but what about start up in these type of temps, by the way I envy you working in that sort of temp/enviro, whislt intense cold has its drawbacks I found it very nice to be in and work in!
Joined: Nov 2001
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From: Iceland
Vfrpilotpb: The biggest problem the guys here in Iceland have when operating in cold temp's like that, is a power drainage of the battery. It has a much lesser capacity at low temp's. Startup can become a problem.
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From: CANADA
Canadians all know of a device called a Herman-nelson.Loved if it starts , hated when it does'nt. I'ts a large space heater, powered by a gasoline engine. Newer ones have Honda engines and start first pull at -40. Heat is then applied to all the important areas of the helicopter. In the case of logging S-61's this can take up to 2 hours to remove snow and ice. The batteries will have spent the night in the drying room of the camp and will be installed nice and warm.
On S-61 's ice can be found in the oddest of places:in the corners of the inlet shield, inside the NFG spring, which will cause jammed yaw pedals.Blade pockets can fill with ice and the upper cargo door rail will collect it in flight.
The start-up limits for a CT-58 are -25 below , and for good reason.If you ever check the oil level at such temps the dipstick will appear to have oil on it with the viscosity and appearance of treacle. Starting with the oil in such a state will overstress the accessory drive.
Winter flying takes a lot more effort on the ground.
On S-61 's ice can be found in the oddest of places:in the corners of the inlet shield, inside the NFG spring, which will cause jammed yaw pedals.Blade pockets can fill with ice and the upper cargo door rail will collect it in flight.
The start-up limits for a CT-58 are -25 below , and for good reason.If you ever check the oil level at such temps the dipstick will appear to have oil on it with the viscosity and appearance of treacle. Starting with the oil in such a state will overstress the accessory drive.
Winter flying takes a lot more effort on the ground.
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From: Canada
Vfrpilot : The aircraft must have already been run or had heaters in it. I could not imagine any pilot starting a cold soaked aircraft and taking off in 3 or 4 minutes.
In Canada there are various pre-heating devices available. Tanis Corporation has heating pads that are attached to the gear boxes, oil reservoirs, and fuel control units.
Most operators of light helicopters in Canada use car interior heaters and insulated engine covers. On a Jet-Ranger
one would go in the transmission area, another in the engine compartement, and a 3rd in the cabin. In addition to car heaters operators also employ heated battery blankets. Of course in the absence of a battery blanket one could remove the battery and keep it inside ( a warm building).
Because of unusaual circunstances I have even seen a 60 watt trouble light placed under the fuel control of a 206 a -40.
Temperatures of -27 would probably require a 10 minute warm up to get all the oil temperatures up into the proper operating range. In addition If I were operating at that temperature and had to wait for a client I would start and run-up the aircraft ever hour or so,.
In Canada there are various pre-heating devices available. Tanis Corporation has heating pads that are attached to the gear boxes, oil reservoirs, and fuel control units.
Most operators of light helicopters in Canada use car interior heaters and insulated engine covers. On a Jet-Ranger
one would go in the transmission area, another in the engine compartement, and a 3rd in the cabin. In addition to car heaters operators also employ heated battery blankets. Of course in the absence of a battery blanket one could remove the battery and keep it inside ( a warm building).
Because of unusaual circunstances I have even seen a 60 watt trouble light placed under the fuel control of a 206 a -40.
Temperatures of -27 would probably require a 10 minute warm up to get all the oil temperatures up into the proper operating range. In addition If I were operating at that temperature and had to wait for a client I would start and run-up the aircraft ever hour or so,.
Thread Starter
Senis Semper Fidelis
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From: Lancashire U K
IHL
Quite possibly the Heli had been used earlier, but the Pilot was scraping frost from the inside of the screen, but thinking about it though, warm moist air inside the bubble will possibly freeze fairly quickly in that sort of temp (-21 indicated at that time) oil already warmed up from a previous flight, would possibly take much longer than air to go really cold.
Quite possibly the Heli had been used earlier, but the Pilot was scraping frost from the inside of the screen, but thinking about it though, warm moist air inside the bubble will possibly freeze fairly quickly in that sort of temp (-21 indicated at that time) oil already warmed up from a previous flight, would possibly take much longer than air to go really cold.
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From: USA
Having done the Alaska thing for a couple of years....we used to leave the aircraft plugged into heaters....removed the battery to the cook tent...removed water filters from the hand pumps....rarely shut down in the field....always had a warming tent set up in the field sites...and when flying IFR on the bigger machines....always remembered indicated altitude and actual altitude could vary quite a bit due to non-standard temperatures. You have not lived until you find your bird filled with snow because a circular vent popped out during the night and the blowing snow found a way inside!
Iconoclast
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From: The home of Dudley Dooright-Where the lead dog is the only one that gets a change of scenery.
It seems that just about everything that must be done to accommodate flying in frigid conditions has been discussed. What is not being discussed is the performance of maintenance under these conditions. Civil helicopters are not designed with cold weather maintenance in mind. Military helicopters on the other hand are. Military helicopters are designed with human factors in mind, which includes the ability to perform certain maintenance procedures while wearing heavy winter clothing to include gloves. I did my stint under these conditions while in the military but I was maintaining civilian helicopters. Believe me it was difficult and almost resulted in frostbite. This activity was performed on icebreakers on Lakes Michigan and Erie in the middle of the winter and in Greenland and as far North as you can get and still be in Canada. I don’t think things have changed since that time (1949-1952) and I believe that the mechanics are still suffering.
