Frost question

Zeldman said:
Yep, did that a lot in the olden days in the bush. Usually used a glove to knock off the ruff stuff and go. Never worried about frost under the wing because of cold soaked fuel.
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I’ve only ever flown one airplane where I’ve seen that, and we almost always landed with little enough fuel that it didn’t stay cold long enough to form ice.
 
James331 said:
Oh... you park outside in AK?

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I could go pages with the NTSB reports of people who offed themselves and killed pax with wing contamination, but let’s just start off with this.

https://www.ntsb.gov/news/press-rel...lots_Wing_Upper_Surface_Ice_Accumulation.aspx
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I have experience with the topic. Your cheap shots don't change that. Can a guy exceed common sense? Sure, but that doesn't make what I do any less safe.

When I get home I'll take a picture of a garden sprayed that's still full of RV anti freeze from last year. All metal. Fits on my stove without the pump screwed in. Works great. You should try it.
 
kgruber said:
That area may not need any ice removal. For instance the King Air has deice boots everywhere except the front of the vert stab.

king_air_200_raisbeck.jpg
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Huh- I see that too. I’d rather be safe than sorry but it does seem like maybe ice could accumulate their in flight.

Seems like we are all not so sure on this one.
 
Stewartb said:
I have experience with the topic. Your cheap shots don't change that. Can a guy exceed common sense? Sure, but that doesn't make what I do any less safe.

When I get home I'll take a picture of a garden sprayed that's still full of RV anti freeze from last year. All metal. Fits on my stove without the pump screwed in. Works great. You should try it.
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Didn’t mean to come off like a cheap shot, but parking outside in AK isn’t a unassailable attribute.

Not saying I’m all that (despite my sig line lol), however learning about wing covers and spraying some type 1, that would be good for most who fly in the north.
 
Frost is kind of a big deal. From my airline’s manual. Notice the warning. EVEN SMALL AMOUNTS OF FROST.....MAY ADVERSELY CHANGE STALL SPEEDS AND CHARACTERISTICS.

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James331 said:
Didn’t mean to come off like a cheap shot, but parking outside in AK isn’t a unassailable attribute.

Not saying I’m all that (despite my sig line lol), however learning about wing covers and spraying some type 1, that would be good for most who fly in the north.
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My point was that I get to deal with it pretty much 100% of the time between October and April. Especially in the fall and spring when I tend leave wing covers off. It rained here all Friday and Saturday. Today my wing covers will be stuck to the wings from a thin layer of clear ice. Assuming there aren't any rough edges? The best way to get it off is to fly it off. Next month the Cessna will move north to the new hangar house. The Cub's already there. I'll still do the wing cover thing at the cabin but 50% of it will go away. I won't miss it.

I have several sets of wing covers including mesh covers with leading edge spoilers for windy days. Those mesh covers can leave a bumpy mess on the wings if moisture gets into them. That kind of fouling requires a hangar. The frost I'm talking about flying with is thin and smooth. I'm not stupid.
 
We get a different kind of ice and for about 6mo, to the point we roll with a backpack sprayer in the plane by default, with AOAs I’ve seen clear detail, just not worth it, if you got crap on your wing get rid of it, it’s not worth the risk. For the light stuff or post covers, some type 1 mixed with hot water will fix it up nice with little effort and $$
 
So for the newbie to frost/flying, what is the water to pink stuff mix ratio? I showed up to our plane on the Wednesday before Thanksgiving and found frost. Went to the store, bought bottled water and towels..... Frozen digits later, we had frost free, dry surfaces....
 
TheFB said:
So for the newbie to frost/flying, what is the water to pink stuff mix ratio? I showed up to our plane on the Wednesday before Thanksgiving and found frost. Went to the store, bought bottled water and towels..... Frozen digits later, we had frost free, dry surfaces....
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For the stuff I linked to on the last page.

Fill the sprayer half up, add hot water from
the FBO bathroom, like 60/40, spray the wings and tail etc, in the direction of the normal wind flow, careful of inlets and pitot and the like.
 
In Bethel, we put sleeping bags over the cowling and wings and kept electric heaters running through dryer duct into both wings. We drained the oil out of the engine and kept it in a pot on a Coleman stove in the hangar.

First the covers came off, then a rope was run over the top of the wing to clear off any remaining ice/snow/frost. We touched up the rest of the plane with a broom and then filled the engine with warm oil. Then, it was start up and run as in normal conditions...
 
IK04 said:
In Bethel, ...we drained the oil out of the engine and kept it in a pot on a Coleman stove in the hangar.
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This brings to mind something I've wondered about for years. In WWII, how they handled the aircraft engines during the incredibly cold periods when they had to be ready at all times?
 
Gerhardt said:
This brings to mind something I've wondered about for years. In WWII, how they handled the aircraft engines during the incredibly cold periods when they had to be ready at all times?
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The ones that had to be ready generally were run periodically to keep them warm.
 
So on a "things they didn't teach you in school" about de-icing. Do FBO's in the frost belt typically have a de-icing service? Even if it's a line guy with a back-pack sprayer. Is there a typical cost?

Have family up north and am going to try and be up there for a day or two weather permitting during the holidays. I've already set the expectation that it's a low probability, but if I get there and need to clean up on a cold, clear day....
 
" ...Test data indicates that during takeoff, frost, ice or snow formations having a thickness and surface roughness similar to medium or coarse sandpaper, on the leading edge and upper surface of a wing, can reduce wing lift by as much as 30% and increase drag by 40%. Even small amounts of contamination such as this have caused and continue to cause aircraft accidents, which result in substantial damage and loss of life. A significant part of the loss of lift can be attributed to leading edge contamination. The changes in lift and drag significantly increase stall speed, reduce controllability and alter aircraft flight characteristics. Thicker or rougher frozen contaminants can have increasing effects on lift, drag, stall speed, stability and control."

From https://www.tc.gc.ca/eng/civilaviation/publications/tp10643-menu-1118.htm
 
Hang 4 said:
So on a "things they didn't teach you in school" about de-icing. Do FBO's in the frost belt typically have a de-icing service? Even if it's a line guy with a back-pack sprayer. Is there a typical cost?

Have family up north and am going to try and be up there for a day or two weather permitting during the holidays. I've already set the expectation that it's a low probability, but if I get there and need to clean up on a cold, clear day....
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Depends on the FBO, here at KFAR they have a ton of option although it will cost you an arm to get you done. Heated hangar will be cheaper if it’s a short stay
 
Gerhardt said:
This brings to mind something I've wondered about for years. In WWII, how they handled the aircraft engines during the incredibly cold periods when they had to be ready at all times?
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There’s a section in “The Blonde Knight of Germany”, a biography about Erich Hartmann, that discusses how a Soviet prisoner demonstrated some ways to keep their planes flying im the Soviet winters. One technique was to fill a pan with Avgas, put it under the engine compartment with the cowling off, and light it. Hartmann was expecting the engine to be pretty much trashed after that and was surprised that it started fine.

Another technique the guy showed them was dunking their machine guns in Avgas to completely remove he lubricating oil which had been congealing causing jams. Said that technique worked also.


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WannFly said:
Heated hangar will be cheaper if it’s a short stay
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I have numerous times seen frost form on the airplane right after it's been taken out of the heated hangar. It was a constant hassle at the flight school on cold, clear early mornings. Frost is a phenomenon caused by the heat radiating from the aircraft surfaces into space when there's no cloud cover. That metal actually gets colder than the air due to the radiation, and water vapor sublimates onto it.

Your car's windshield is much less likely to frost up on a cloudy night, or if it's parked in an open carport. Same with an airplane. Just have to stop the radiative heat loss.

We used a garden sprayer and the orange Type 1 fluid, but I had to buy a whole drum of the stuff. Enough to last quite a while. And not cheap. But far better than the isopropyl/water mix some people used; the alcohol would evaporate rapidly, cooling the surface even further and leaving the water behind to freeze solid.
 
Could someone point me to the science that says aircraft surfaces "radiate heat" and become colder than the ambient temperature of air? I can see the wing being colder than ambient due to fuel inside colder than ambient and that cooling the wing, but without a colder material inside the wing, the wing should normalize to what ever the air temp is over a relatively short period of time absent sunlight on it or mass inside with a colder temp.
 
Push a warm vehicle into the cold and it'll often frost up. It depends on the humidity. Bring a cold vehicle into the warm and chances are better for fogging up. Humidity at work again.
 
Another bush trick I used to do was to keep a hand held spray bottle full of Isopropyl alcohol. A few pumps on a patch of light frost and away it goes. Then use a dry towel to wipe off the moisture so the water doesn't puddle up and re-freeze.

I have seen heavy dew freeze up on the wings right at rotation leaving the drops frozen on the wing. Something else to think about.
 
How do you zero-tolerance frost guys deal with the windscreen?
 
PaulS said:
Could someone point me to the science that says aircraft surfaces "radiate heat" and become colder than the ambient temperature of air? I can see the wing being colder than ambient due to fuel inside colder than ambient and that cooling the wing, but without a colder material inside the wing, the wing should normalize to what ever the air temp is over a relatively short period of time absent sunlight on it or mass inside with a colder temp.
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It comes from the evaporation of the fluid. From Wikipedia:

Definition of heat of vaporization. : heat absorbed when a liquid vaporizes specifically : the quantity of heat required at a specified temperature to convert unit mass of liquid into vapor.
 
WannFly said:
Depends on the FBO, here at KFAR they have a ton of option although it will cost you an arm to get you done. Heated hangar will be cheaper if it’s a short stay
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Even in a cold hangar you’ll usually be frost free in the morning. And much cheaper than a heated hangar
 
Skip Miller said:
It comes from the evaporation of the fluid. From Wikipedia:

Definition of heat of vaporization. : heat absorbed when a liquid vaporizes specifically : the quantity of heat required at a specified temperature to convert unit mass of liquid into vapor.
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What fluid is evaporating when you pull a warm airplane into cold air?
 
PaulS said:
Could someone point me to the science that says aircraft surfaces "radiate heat" and become colder than the ambient temperature of air? I can see the wing being colder than ambient due to fuel inside colder than ambient and that cooling the wing, but without a colder material inside the wing, the wing should normalize to what ever the air temp is over a relatively short period of time absent sunlight on it or mass inside with a colder temp.
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https://en.wikipedia.org/wiki/Radiative_cooling

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=8&ved=2ahUKEwjXu9PD3ZjfAhVn8IMKHXGsDUMQFjAHegQIBhAC&url=http://www.asterism.org/tutorials/tut37%20Radiative%20Cooling.pdf&usg=AOvVaw1HxbbqZMuq2RmbPeWG9rs-

https://www.google.com/url?sa=t&rct...t%202011.pdf&usg=AOvVaw23cLpJ3MmsPxhTyoJQUdUW
 
I’ve used the windshield de icer spray for cars, seemed to work well... I kept it off the windscreen as I wasn’t sure about it and plexi.

If Wing covers are too pricey- go to any second hand store buy an old sewing machine, fire up YouTube and make some. I did boat seats- never sewed a stitch in my life before that... something of simple shape is not overly difficult, material is cheap... I’m going to make a cowl and prop spinner cover. I don’t foresee need for wing covers or I would... but it can be done and they do allow guys into JoAnne fabrics ;)
 
Bobanna said:
If you don't mind being followed-around by security.
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Lol no doubt! The ladies in there shopping were always very helpful they thought it was "cute" i was sewing.
 
Speaking of frost on the ground, how does it relate to in the air,? Every morning and evening here the dew point spread is between 0-4, as a personal minimums I try to avoid it, but it’s putting fairly big hole in my flight time... I know the less the dew point spread is the greater the chance of things turning out MVFR or even IFR OR the hanging particles in the air sticking to the airframe especially when the the OAT is around 30C. Relative humidity should play a role, but I just not experienced enough to interpret when it’s not gonna be a problem... insights?
 
WannFly said:
Speaking of frost on the ground, how does it relate to in the air,? Every morning and evening here the dew point spread is between 0-4, as a personal minimums I try to avoid it, but it’s putting fairly big hole in my flight time... I know the less the dew point spread is the greater the chance of things turning out MVFR or even IFR OR the hanging particles in the air sticking to the airframe especially when the the OAT is around 30C. Relative humidity should play a role, but I just not experienced enough to interpret when it’s not gonna be a problem... insights?
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I don’t think frost can develop in flight. If you have visible moisture( like rain,clouds) and then fly into below freezing temps, you would accumulate ice— not frost. A CFI once told me that it is far better to fly into snow than rain on a cold day as snow is already frozen and will have a much harder time sticking to the wings than rain and the rain will eventually turn the plane into a block of ice!

With regards to dew point spreads, you are right to be cautious but if I cancelled a flight everyrime the dew point spread was between 0 and 4 I’d have about half as much time as I do now. On these days with small spreads I may expect more potential for low clouds and maybe more moisture in the air but unless there is a significant weather influencer around( cold front/warm front) I don’t worry much about these close spreads. You got to keep in mind that these spreads are calculated by weather stations on the ground. We all know that on most days, as you climb higher the air gets colder and this creates, by nature, a difference in the temp/dew point spread.
 
WannFly said:
Speaking of frost on the ground, how does it relate to in the air,? Every morning and evening here the dew point spread is between 0-4, as a personal minimums I try to avoid it, but it’s putting fairly big hole in my flight time... I know the less the dew point spread is the greater the chance of things turning out MVFR or even IFR OR the hanging particles in the air sticking to the airframe especially when the the OAT is around 30C. Relative humidity should play a role, but I just not experienced enough to interpret when it’s not gonna be a problem... insights?
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It’s visable precip you got to worry about, that ofcourse includeds low visability, if it clear outside you’ll be fine.
 
PaulS said:
Could someone point me to the science that says aircraft surfaces "radiate heat" and become colder than the ambient temperature of air? I can see the wing being colder than ambient due to fuel inside colder than ambient and that cooling the wing, but without a colder material inside the wing, the wing should normalize to what ever the air temp is over a relatively short period of time absent sunlight on it or mass inside with a colder temp.
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I guess the same way that the ground radiates heat and becomes colder than the air above it?

Just last week frost formed on the upper surfaces of my plane (and all the cars in the parking lot) and the AWOS was reporting a temperature of 4°C. This was only an hour after sunset.
 
Moisture precipitates from the atmosphere as temps drop. That's why frost is on top and not the bottom of wings, unless there's ice fog.
 
I would never advocate for flying with frost on your wings, I'm not sure I am buying the FAA statement of 30% higher stall speed. I have had some airplanes with paint jobs that were rougher than any frost I've seen that still flew book numbers. That said, I would still remove any containment as the time isn't worth the risk.
 
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