Cruise speed drops with the time!?

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Obi
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Cruise speed drops with the time!?

Post by Obi »

Hey Guys! Im @ 8000 Feet with my 182 and she constanly get slower. First from 120-100knots. than from 100-80.. i have the autopilot active and she nearly stall O,O

Full throttel,
mixture about 45%,
Rpm at 2300,
cowlflaps closed

and i nearly drop´d from the sky!?

can anyone help?
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Molly - A2A
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Re: Cruise speed drops with the time!?

Post by Molly - A2A »

What were the weather conditions?

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Obi
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Re: Cruise speed drops with the time!?

Post by Obi »

cloudy, 27°F,

pilot heat is on
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AKar
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Re: Cruise speed drops with the time!?

Post by AKar »

If your engine indications were good, then it probably is weather related, some kind of weird icing issue or something that FSX throws in.

I wonder if fuel injector icing can occur in Accusim, I believe not.

-Esa

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Obi
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Re: Cruise speed drops with the time!?

Post by Obi »

ok... i deactivate the real wather and chose a wether option from fsx. and now my speed is at 120knots indicatet and 160 over ground. I also change the prop..

absolutly no idea whats gonna on. Maby Prop Icing?
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Molly - A2A
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Re: Cruise speed drops with the time!?

Post by Molly - A2A »

FSX does have a simplistic ice modelling, which can be made more severe when using various real weather programs.

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Lewis - A2A
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Re: Cruise speed drops with the time!?

Post by Lewis - A2A »

Yes FSX uses a realxed realism icing simulation. You should treat the Accu-sim aircraft as you would real aircraft, the GA aircraft are not all weather flyers. Watch that weather like a hawk as you would in the real world.

thanks,
Lewis
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crum
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Re: Cruise speed drops with the time!?

Post by crum »

Lewis - A2A wrote:Yes FSX uses a realxed realism icing simulation. You should treat the Accu-sim aircraft as you would real aircraft, the GA aircraft are not all weather flyers. Watch that weather like a hawk as you would in the real world.
Lewis, and what kind of icing is simulated for 182T?
Pitot tube blockage is obvious, but what else?
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Scott - A2A
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Re: Cruise speed drops with the time!?

Post by Scott - A2A »

We model the pitot icing, and while we do have an airframe icing system in Accu-Sim, it is not active.

Scott.
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crum
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Re: Cruise speed drops with the time!?

Post by crum »

Scott - A2A wrote:We model the pitot icing, and while we do have an airframe icing system in Accu-Sim, it is not active.
I see. Nice to know you have airframe icing in the works! Hope you'll enable it soon.

But then what did happen in Obi's case where he barely stalled? He says pitot heat was on and it seems like there was a real drop in speed not only indication.

Never met any similar problem yet, but it's quite interesting.
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SkipperMac
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Re: Cruise speed drops with the time!?

Post by SkipperMac »

crum wrote:But then what did happen in Obi's case where he barely stalled? He says pitot heat was on and it seems like there was a real drop in speed not only indication.

Never met any similar problem yet, but it's quite interesting.
Airframe icing, compliments of FSX :D With pitot heat on, the ASI was showing his actual IAS which, with the weight and drag of the ice accumulated on the airframe, would be much lower than normal cruise and would mean his stall speed was much higher than would normally be expected. Sadly, FSX has no in-built visual representation of airframe icing which you would normally see and rapidly descend to lower, warmer air to get rid rather quickly (if you were wise and not wanting to test the limits of the sim lol).

Roll on the day when some developer works out how to 'show' airframe ice without totally destroying frame rates (compare the PMDG J41 for instance). A2A, are you facing up to the challenge? Seems that the 182 would be an excellent airframe to test it on :wink:
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crum
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Re: Cruise speed drops with the time!?

Post by crum »

SkipperMac wrote:Airframe icing, compliments of FSX :D With pitot heat on, the ASI was showing his actual IAS which, with the weight and drag of the ice accumulated on the airframe, would be much lower than normal cruise and would mean his stall speed was much higher than would normally be expected
Some time ago I investigated FSX capabilities in airframe icing quite deeply and it's influence was so subtle (in most severe icing conditions), that it could not form enough amount of ice in reasonable time to make plane drop from the skies. So, I believe in this exact case there could be some other not so obvious effect.
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Lewis - A2A
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Re: Cruise speed drops with the time!?

Post by Lewis - A2A »

What you might have considered severe icing conditions crum are not what the default system does. Its very rudimentary and also can be like the default recording system, it doesn't work but always works 100% of the time :?
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