Realism Question

[Nonno]

I decided to reinstall the Beaver X the other day. Since I hadn't flown it in some time I wanted to get an idea how realistic it was when it came to cold weather situations. So I took it up to Point Hope in Alaska and flew it up the coast for about 25 nm, with no carb heat, no pitot heat. The temp was -27 degrees cel. I climbed to 9000 ft. with no problems, turned around and headed back to Point Hope and landed with no problems. I forget what gauge it was but it did show a temp between -20 and -40, so it did recognize the cold.

This didn't seem right to me, I would have thought for sure I would have had some kind of problem somewhere along the way. So, I pulled out the trusty Piper Cub. I flew the exact same route, figuring that the Cub would tell the true story. I was really surprised when I was able to fly her right on up to 9000 ft. with no problem and turn her around and put her on the ground without ever touching the carb heat. So, now I'm really confused.

That's what brings me here, I think there are many smart guys on here that can give me the right answer. Accusim was on. It was a sunny, mostly cloudless day. So, what do you think? Realistic or not? Thanks

[CodyValkyrie]

Having lived in Alaska, and having flown in such extreme temperatures, I can attest to the accuracy of what you saw here.

Often, when it gets that cold there is very little moisture actually in the air... hence no clouds. There is sometimes an ice fog on the ground, but not always. The problem is STARTING the planes in the cold. If they are hangered, this is usually not a problem. If they are not.... well, good luck. Cars are the same way, which is why we had engine block heaters, battery blankets and oil pan heaters that we would plug in.

SO, once you get her in the air, as long as you are not flying through clouds, there is little moisture to actually freeze your pitot or produce icing in the carb. This does NOT mean however that you will not freeze your carb. The Cub is pretty bad about carb icing, especially if there is any moisture in the air due to the long throat. Some of the worst icing conditions you could encounter would actually be in warmer moist climates, even in the Caribbean as the venturi effect would condense any air, cool the moisture build up and produce said icing.

As a matter of habit, you should ALWAYS turn on carb heat during a decent with the throttle far back. This doesn't necessarily mean that it will indeed happen, but once it does happen, it may be too late.

In the air you were flying in, we noticed very little icing, and the simulation is showing this situation as well. It could get as cold as -50 on the ground in Fairbanks. You will notice when the temperature rises in these places, often there are clouds present and the humidity rises. Notice also in those extremely low temperatures the high visibility above ground level? In Fairbanks, when the Chinook winds blew through it would get up to -10 - 0 degrees F with an overcast or broken ceiling. It was during these conditions that you needed to be more concerned about icing.

It was common for people to try the warm water trick when it got below -25. We would simply take a "warm" or "hot" cup of water and toss it into the air. The water would instantly evaporate.

It was during dead winter while I was working on my PPL. As long as the ice fog wasn't too bad (and usually by midday it was gone), the flight was easy. The old 172 I used to fly in never had a problem in the cold, and as a matter of fact it actually flew better in the thick cold air. I enjoyed flying best in these temperatures as it was very smooth, predictable and the visibility was amazing.

What you saw sounds accurate however to what I experienced.

[Nonno]

Thanks a lot for clearing that up for me. I didn't know how the Piper would react in the cold clear air. I really appreciate you taking the time to explain that to me. Thanks again!

[skunker]

Down here in South Texas, it is often very hot and HUMID. HUMID is the key here...and we have to constantly be concerned about carb ice in flight, especially with these little Continental engines.

[pjc747]

It also depends on density altitude. See, if it's cold, but the density altitiude is lower, the engien will function better because you get the power and output of say 7,500 instead of 9,000. On tyhe other end of the spectrum, carbeurators don't work well at higher altitudes, so it depends on how you have you speed set, and how the engine performes. All carbeurators work a bit differently at altitude. Also depends on dew point, at what temperature condensation will appear on things, and paossible freeze depending on conditions, speed and of course altitude.

[seaniam81]

This Chart will help for future reference
http://www.atsb.gov.au/media/56519/carb_icing.pdf