'Plastican' fuel containers are also good at carrying TKS fluid in. (OK for re-filling your ice protection tanks, no good for de-icing your aircraft though).

200 litres should last you an age! I'd be more worried about it having an expiry date than running out of it to be honest! Especially if you mix it with hot water too.

Steven, try here to get some. LAS - Kilfrost Products

Get a couple of containers, lock them away in the hangar with your name on and get a sprayer from B&Q. Borrow a step ladder from the fire shed and spray away!

Good lead sayitagain. Many thanks.

Killfrost has a new very interesting product in its range called Killfost sustain, which looks to be very well suited to aircraft parked out on grass. Kilfrost | Kilfrost SustainIt has both a low energy production process and is biodegradable.

hello neilgeddes -
 

From your initial question, you do have time to spare. the next two suggestions from mm flynn and englishal I think really cover the situation nicely. As for buying antifreeze spray and gunk, that sounds like money for trouble later. Lavish use of water even in fine weather leads to corrosion.

Lucky you to have a hangar to keep the pride and joy safe.... refuel the day before, keep it full if possible (this prevents condensation accumulating in your tanks).

As for predicting frost on the wings and tail, your car in the morning will give you an idea of the problem! No hurry, you've done all the planning before you roll it out. Fog and low cloud? decide on some other activity. Cold bright sunny day, best of all. The improved performance will be a revelation.

It was -18ºc in mid Wales last night and I have seen indicated temps of -20ºc when driving in Scotland.
My niece had to be rescued this morning after a night shift at the hospital she works at as the brakes on her car had frozen solid. It was only -10ºc there!

SayItAgain slowly

While I agree with a lot of what you are saying about using water I cannot totally agree.

Water from a bucket is not the only way of the airframe getting soaked.

I can remember a difficult instant in a Seneca Where I was held in a torrential donwnpour at 3000 feet awaiting a climb clearance into CAS to FL120.

I got the clearance trimmed the aircraft in the climb. The rain diminshed as the aircraft climbed and on reaching FL120 I attempted to level.

The trim wheel had frozen solid and using power and a lot of out of trim forces I had to descend to warmer air until the trim wheel came free again.

This was a result of intense rain not from a bucket.

I have used warm water but only on the leading edges which are the most important bits and over the screen.

If used very carefully and away from any moving surfaces where water could get into the control lines etc it is a useful way of helping remove ice.

I totally agree the correct fluids are better if available but dont discount water if used with utmost care.

Pace

20 litres, not 200 litres, SAS.

After all this typing, I just saw that Pace made a rather better post. Oh well,

Say Again:

I believe water would work in the end, it's just the quantity that makes it impractical.

I did a few ball-park calculations for a C172 at -2 deg C.

If some 30 sq m of wing, fuselage, etc is covered in 1mm of frost, that is 30kg of ice at -2 deg.

The specific heat of ice is 0.5 kCal/kg/degC (also cal/g/degC)
so we need 2 x .5 x 30 = 30 kCals to get it up to zero.

Then we need the latent heat of fusion/melting, 80 kCals/kg/degC.
80 x 30 = 2400 kCals.

Then, to mop it up without it freezing, we want it at perhaps +3 degs, so with a specific heat of 1, we have
3 x 1 x 30 = 90 kCals.

So that's 2520 kCals to clear the ice and get it to a moppable temperature.

But we also have to warm the aircraft and fuel from -2 to +3, ie through 5 degs C.

Say 500kg of Aluminium at 0.2 kCals/kg/degC is:
5 x .2 x 500 = 500 kCals

Say 135kg of fuel at at 0.5 kCals/kg/degC is:
5 x .5 x 135 = 338 kCals

Which gives us a total of 3358 kCals required.

Ordinary water at 10 degs C will have 10 kCals/kg of useful heat for clearing the ice (which is most of the requirement), and then down to 7 kCals/kg for heating the airframe. So at least 335 litres will be required.

But with such small temperature differences the heat transfer will be poor (except for the very first water which freezes on contract) and I suspect we are talking about at least a tonne of water, very slowly and painstakingly applied.

Warm water does't help much because in thin sheets it evaporates and cools quickly, giving up heat to the atmosphere instead of the airframe.

So not very practical.

There is also the little issue of what happens to the water. Putting a tonne of ice on an apron may not be popular, nor making a huge muddy patch in a field.

Sorry IO, I was speed reading that and horlicksed it up!

Pace. I understand what you are saying. However, you flew into icing conditions and fortunately got out of it.

I've had plenty of experiences with in-flight icing, fortunately though it's usually on machines with proper kit. I remember one fight coming back from Le Bourget when we got caught up in the top of a growing CB. We picked up ice at a horrific rate, even though every bit of kit was going full bore.

We slowed by 30kts in a couple of minutes even though we were at max continuous power. The aircraft was empty and we had 2 PT-6's giving it the beans and that still wasn't enough.

We did a dirty dive into our home base and once we landed the amount of ice on the airframe was horrific. It was a couple of inches thick and I shudder to think what would have happened had we not been in an aircraft with full kit on it and all the excess power we had available. When you pick up ice, it happens fast.

At no time did we have any control issues though.

There is no need to take the risk with using water as a de-icing fluid. Proper fluid is easily available and isn't that expensive, especially not in comparitive terms to the other costs in aviation!

Pouring water of any temperature over a sub zero aircraft is silly. It will always leave a tiny bit of a layer behind it unless you rub away at it for an age an inspect it very closely and as we all know, ice begets more ice.

Use the proper stuff and totally de-ice the aircraft in the correct manner or don't bother going flying. It's not hard really! It's also a darn sight faster and easier than mucking about polishing the aircraft to get rid of every last bit.

Now, the FAA do allow ice polishing and then to go flying in certain circumstances, but the best solution is to rid yourself of all of the ice.

Great analysis, 24carrot :ok:

I have long forgotten how to do the latent heat of fusion calculations but the principles remain :)

It's actually not as bad, however.

I may need to get my coat after this but the areas from which one really needs to remove frost are the aerodynamic surfaces, the prop, and the windows. Frost on the cowling and the roof doesn't matter. I have flown my plane covered in spattered flies, and covered in firmly stuck-on grass cuttings (from landing in a field with ~ 10" grass) and it made no visible performance difference.

You don't need to warm up the engine etc etc to +3C. In fact with an OAT of say -2C (a pretty common UK morning scenario) the cockpit temp will be easily +5C once the windows are clear. I have done some RH measurements (to test the effectiveness of silica gel to keep an unpressurised and thus not well sealed cockpit dry) and the solar heating even in murky daylight is substantial.

+10C tap water applied to the airframe at -2C will simply not freeze. The frost comes straight off and the water runs off and that's it. The specific heat capacity of 1-1.5mm aluminium and window etc plastic is miniscule.

It is the wings which are the problem and that is what I found doesn't work. I don't think any practical quantity of water will warm up the wing tanks from the lowest temp seen the previous night (say -5C) to something positive.

I know a lot of people use car fluids but that is IMHO highly dodgy.

24 carrot. Don't waste your time calculating stuff like that. Spray the aircraft with de-icing fluid and leave the test flying to the pro's.

People often like to think they should reinvent the wheel in aviation, but I can promise you that the correct and prescribed methods for things like de-icing have come from years of long and bitter experience, often paid for by people's lives.

Don't p*ss about with ice or water. Buy the right stuff, apply it properly and you'll minimise the chances of killing yourself because of ice issues. If you haven't got the kit to do it right, don't be stupid, get back in the car, go home and then walk to the pub and enjoy a pint.

Cutting corners in aviation only ever leads to trouble. Keep It Simple.

Edit to add: I can assure you that it is more complex than simply looking at energy and things like latent heat. The airframe wouldn't cool or heat in an equal manner and there are a whole heap of different materials that have different thermal properties.

The problem with stuff like this, is that someone will read it and think that they know better than the usual teaching and then try it. These people are known as idiots, but there are plenty of them in the flying world.

SayAgainSlowly

My arguement was to describe that in heavy rain the airframe is getting a soaking which could lead to water getting into the control linkages etc.

Obviously an aircraft is moving at 150 kts plus through the air while an aircraft on the ground is static when you pour your bucket of water over it.

That was the only occasion when I have ever had a control freeze. I have 3000 hours in Seneca Fives and have flown them all over the place in all conditions so know them pretty well.

On that occasion the rain was in plus temperatures and the aircraft flew up into freezing air. Strangely I did not pick up ice in the climb but water from the heavy rain lower down had obviously got into the controls and frozen solid.

Pace

Say Again Slowly:

If you read my post again, you may notice I did not recommend using water.

Which is as to be expected. Flying through water with a cold airframe will lead to ice problems. One of the reasons it is to be avoided.

24 Carrot. I saw that. I know you think it's a daft idea, but someone else might read it and then try it. They're the one's I'm worried about!

I would also avoid Type IV fluid unless you are prepared to thoroughly clean off any residue at the end of the flight.

We had trouble at work with it solidifying inside the mass balances on the elevator and causing vibration after a few applications.

So... what stuff is 100% safe - apart from Aeroshell fluid #7 which appears to cost £200 for a 20 litre drum?

IO540, could your wings, unlike the rest of the aircraft, be a lot colder than the minimum night time air temperature? Perhaps the ground, (which cools the air), and the wings undergo radiation cooling at different rates?

It is very noticeable that car roof tops frost over more than the sides of cars, unless the car is tilted (eg on a cambered road) when the part pointing at the sky is the most frosty. You can see similar effects when there is a tall building on one side of the car.

The only thing that is 100% safe is to not go flying if you have ice.

Other than that, use the Kilfrost or Aeroshell or A.N.Other approved fluid.

Could you imagine if something did happen to you and it was discovered that you'd used a non-approved de-icing method? Wave cheerio to any insurance payout for both the aircraft and yourself.

These fluids aren't a panacea and they do have to be used correctly, they can also add other problems as demonstrated by JW411. However, they are the most sensible way for people flying GA aircraft to clear ice as safely as possible, other than to hangar it and avoid the stuff in the first place.

Seriously though, when you have an aircraft worth a few hundred grand and running costs that would horrify sensible people, the cost of using the correct de-icing fluids is so small as to make it irrelevant. Especially given the potential problems that not clearing ice can lead to.

I think it is simply because the supercooled water droplets are coming down more or less vertically, unless modified by some local airflow, and then it freezes up to create frost.

That's why one doesn't get frost underneath the wings, IMHO.

The wing tanks will definitely be colder. If I turn up to fly at 9am and it is -2C, I bet the fuel will be at say -5C from the middle of the night.
I thought that an American Express card was approved for this purpose; it seems to be widely used by instructors :)

Personally, I would use a Santander card - this is the most arrogant institution around today.