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PostPosted: Tue Dec 27, 2016 8:56 pm 
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I encountered carb icing during a flight today so I used it to try and get an idea of how quickly the anti-ice fluid worked. During my testing it appears that switch 1 OR 2 clears the ice on engines 1 AND 2, same thing with switch 3 or 4 working for both engines 3 and 4. Reading up on the system it appears that even though the pumps on each side are both in the outer nacelles they are each only plumbed to a single engine.

So I was wondering if the way it works in the sim was intentional?


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PostPosted: Tue Dec 27, 2016 9:00 pm 
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I can't honestly say I saw that during testing, but an important note here is that you should only be using the Carb Anti-Icing as a last resort because it uses Anti-Icing fluid, which is in very limited supply. Instead, you should be using the Carb Air first, and only when it's at 100% sheltered, then you kick on the Anti-Icing. In our testing and in the available reference I've found, the Carb Anti-Icing was rarely needed, and is probably why the L-049 was the only version to ever use it and one of the very few airplanes ever to use such a system at all.

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PostPosted: Tue Dec 27, 2016 9:33 pm 
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Thanks for the reply. I was mainly trying to adhere to the advice in the manual that warns against using heat during high or normal power settings due to detonation risks, and also just to try it out. But yeah if icing had been a real concern I would have climbed, descended, or reduced power so I could use heat.


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PostPosted: Wed Dec 28, 2016 9:00 pm 
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The advice is to avoid carb heaters when using "high" power settings. In 1950's parlance, this means power settings at or above METO. As normal climb is below METO, you're okay to use the levers. Sorry if there was any confusion.

BTW, I will make sure this is on the list for testing.

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PostPosted: Wed Jan 11, 2017 3:09 am 
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I have also question about carb. air.
During flight carb. air temp. is -25, and carburetors do not freeze, FE do not touch carburetor air levers.
So is it ok ?
When carb. air levers should be used ?

Manual also says that when carb. air levers are moved by 10% then air filters are active.
Never saw that in action, when filters should be used ?


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PostPosted: Wed Jan 11, 2017 7:17 pm 
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First, make sure you're looking at the Carb Air Temp gauges. Just because it's -25*C ambient, the CATs may still well be positive, especially when using high power settings.

Carb air is only used when the carb air temps are in the freezing range (+2 to -10*C) and there is icing present. You will rarely if ever see the Carb Anti-Icers turned on as they are a "last resort" used only when the Carb Air is insufficient to clear the ice.

It is okay for the CAT to go negative at high altitude as long as you're not continuously in clouds or precipitation. This is actually beneficial to the engines as it puts denser air into the engine and thus you get better fuel consumption and a more complete ignition.

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PostPosted: Wed Jan 11, 2017 11:29 pm 
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I'm sure that carb.air was -25, ambient temp. was -40.
( i do flights in Northern areas: Alaska, Syberia )
I'm just wondering why carburetors do not freeze ?

In case freezing ( which so far did not happen to me ), i understand that first action is to use carb. air levers, and if those are inefficient then we use liquid carb. de-icers, i hope i'm right.

Question about "air filters" is still unclear for me ?
Appreciate for clarification about it.


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PostPosted: Thu Jan 12, 2017 5:05 am 
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Well temperature is not the only factor for freezing. If there's only very little humidity then there will be no water that could actually freeze. So even though you might have temperatures well below 0C you light not encounter carb icing. On the other hand you could get carb icing in positive ambient temperature with high humidity.

But what I don't understand either is why the flight engineer doesn't engage the carb heat when you have icing. I actually had carb icing yesterday to the point where the manifold pressure dropped and the virtual engineer was in charge of his station and he didn't engage the carb heating. So I had to take over to engage it. When I returned him to his duties he turned the carb heat back off. Is that bugged maybe?

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PostPosted: Thu Jan 12, 2017 12:13 pm 
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You might try re-installing the airplane because he works fine on my copy. Did the "Shift-2" panel say "Carb Icing" on it?

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PostPosted: Thu Jan 12, 2017 12:39 pm 
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CAPFlyer wrote:
You might try re-installing the airplane because he works fine on my copy. Did the "Shift-2" panel say "Carb Icing" on it?

Yep the shift+2 panel said carb. icing and then I started loosing manifold pressure. Just to verify he should pull the carb air levers next to the engine throttles on the engineers station to hot correct?

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PostPosted: Thu Jan 12, 2017 9:28 pm 
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That is correct. He should also say "Sheltered Air" when he does so. I will be home from the road tomorrow afternoon and will check to see if I'm getting proper operation or not on my end. We had a bug jump into one of the Release Candidates that caused him not to work, but Scott thought he got it fixed.

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PostPosted: Fri Jan 13, 2017 12:47 am 
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Ok. I'll try to reproduce the issue on my end too. Thanks for looking into this.

Happy flying

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PostPosted: Fri Jan 13, 2017 4:20 am 
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Hey guys I've noticed this too.

Only on 2 occasions in 40 odd hrs has the FE operated the Carb air levers, and associated switches whilst in full control of his station.

The first time was just after starting whilst still on the ground, the temp was around zero and it started to rain.
It was the first time I had also heard him say "Ram Air" and "Sheltered Air" etc.
And the second time was yesterday on a low level flight around Wales during rain.

All other times I've had the red Carb ice warning on the shift 2 notes, I had to switch them on and off myself.

I also noticed that when he does operate the Carb heat levers, the wing and prop ice switches are also on, those are the only 2 occasions when I've seen them switched.

But yeah, most of the time the Carb Ice warning appears he does nothing. Unless it's raining it seems.

John.

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PostPosted: Fri Jan 13, 2017 6:28 am 
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Interesting. Maybe it is related to precipitation? I had icing in clouds with no precipitation and the FE didn't do anything about the icing.

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PostPosted: Fri Jan 13, 2017 7:00 pm 
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He should be activating the wing/prop switches and using Carb Air once actual ice accumulation begins and he "notices" it. It won't be instant, but it also shouldn't take more than a minute at most before he responds.

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