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Jim Padgett

Anti Ice performance ?

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Climb performance?

When ever I am climbing out say at 13000 to 21K , I do alright until I have to turn on de-icing then no power... even if I am at 21K and at around 220 knots... turn on anti-ice and I slow to 150knots...

 

Is this right?

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This is one thing that really surprises me about the J41.  The only things I can suggest is to plan for it before flight...reduce your load.  As I understand it, the icing detector is very sensitive so it'll report even the tiniest amount of ice so the light coming on is not a dangerous event.  Still, you have to respond.  What I have done in flight is, when speed falls below 170 KIAS, push the condition levers forward and then add more throttle.  If you can't maintain at least 170 KIAS then you will probably have to get down below the icing conditions.  That's what surprises me because you don't hear of a lot of aircraft having to do that and yet it seems common with this aircraft.

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Remember that this is not your normal aircraft.  It's not a jet like most of the other aircraft you're probably used to flying.  This very topic is covered in the documentation, so that should be given a read (I believe even the tutorial makes light of it).

 

The engine anti-ice saps a lot of performance from the engine because of the increase in the operating temperatures during their use.  The manual/tutorial mentions that cruise altitudes would be restricted any time A/I was planned to be used.  Additionally, remember that A/I only needs to be used in icing conditions (between +10 and -40 C, with visible moisture).  While the ICE DETECT lights is very finnicky and sensitive, dispatchers and anyone planning the flight would likely check to make sure the flight avoided ice.  The primary method for this avoidance is in lowering the cruise altitude (under the clouds, or where it's warmer).

 

It is, however, possible to just climb at a lower climb rate while remaining at 98% and at the temp limiter until the A/I is no longer necessary.  This method is only really useful for longer flights, otherwise, the reduced rate would mean that you're not going to hit your cruise alt.

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While the ICE DETECT lights is very finnicky and sensitive, dispatchers and anyone planning the flight would likely check to make sure the flight avoided ice.

 

Hi Kyle, from a practical standpoint...by this I mean that many pilots know that the Ice Detected light is very sensitive...would they ever ignore it?  I mean, if it comes on and you're in the clear at +2 C...it's possible you'd pick up some tiny bit of ice but nothing intense enough to need more than Air Data.

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Hi Kyle, from a practical standpoint...by this I mean that many pilots know that the Ice Detected light is very sensitive...would they ever ignore it?  I mean, if it comes on and you're in the clear at +2 C...it's possible you'd pick up some tiny bit of ice but nothing intense enough to need more than Air Data.

 

Hey Gregg - I think the tutorial, or one of the documents Robert wrote alludes to there being many grains of salt taken when it lit up.  If I'm definitely in the clear (no visible moisture), I personally ignore it.

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I just turned my icing effects off. I usually hand fly to the top and back down and continually addressing this single pilot gets tough. I always fly in weather with AS 2012. I have not flown it this way yet though.

 

Thanks,

Ron

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Once the Engine and Elevator Anti-ice is selected on, thrust/torque available at EGT VRL (Variable Red Line) will be reduced, because air is being bled from the compression stages of the engine in order to heat the engine air intake - this means less air flowing through the combustion stage of the engine to cool it, so EGT for a specific power setting will increase.

 

This increased EGT may result in thrust/torque being limited to such an extent that climb performance becomes sluggish (<650 fpm), in which case it is permissible to advance the condition levers up to 100% rpm to reduce EGT, allowing more thrust without exceeding EGT VRL. If you're still encountering climb issues, you may need to cruise at a lower altitude until clear of icing conditions.

 

I've covered the subject of icing conditions and anti-ice measures on the J41 in a brief but fairly detailed FAQ available from:

http://viaintercity.com/forum/viewtopic.php?t=3

If you have a quick read through it, hopefully it should answer all your questions :smile:

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