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 Post subject: Engine problem?
PostPosted: Sat Dec 09, 2017 3:13 pm 
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Even after a complete overhaul it doesn't reach 2400 rpm at full power at standstill (keeps no higher than 2300). Is it really normal for an engine with a CSP? I've always assumed that it is not and wouldn't actually fly such an a/c in the real world until serviced...


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 Post subject: Re: Engine problem?
PostPosted: Sat Dec 09, 2017 3:46 pm 
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Location: Typically hanging around N07, 12N, KLDJ, KCDW
Check the calibration and sensitivity of your prop axis. Your prop axis control may not be fully forward.

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 Post subject: Re: Engine problem?
PostPosted: Sat Dec 09, 2017 4:01 pm 
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Oracle427 wrote:
Check the calibration and sensitivity of your prop axis. Your prop axis control may not be fully forward.

I don't have an axis assigned to prop.


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 Post subject: Re: Engine problem?
PostPosted: Sat Dec 09, 2017 4:11 pm 
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Location: Typically hanging around N07, 12N, KLDJ, KCDW
Where is the prop control set in the virtual cockpit? Is it fully forward?

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 Post subject: Re: Engine problem?
PostPosted: Sat Dec 09, 2017 4:13 pm 
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Oracle427 wrote:
Where is the prop control set in the virtual cockpit? Is it fully forward?

Yes, of course. I even tried CTRL+F4 (prop full forward) to be sure.


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 Post subject: Re: Engine problem?
PostPosted: Sat Dec 09, 2017 4:19 pm 
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Location: Typically hanging around N07, 12N, KLDJ, KCDW
What altitude is the airfield at? Perhaps you are too rich for the density altitude?

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 Post subject: Re: Engine problem?
PostPosted: Sat Dec 09, 2017 4:19 pm 
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Unlikely. It was at Diamond Point (2WA1), 265 ft MSL.


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 Post subject: Re: Engine problem?
PostPosted: Sun Dec 10, 2017 6:19 am 
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I think the behaviour you're seeing is 'normal' for the simulation Ilya. However, I'm assuming that once you start rolling for the take-off, RPM increases to redline rather quickly? (Performing a static full throttle runup with a headwind of 15-20 kts should take RPM to redline too.)

I noted the apparently disproportionate effect of very low airspeed on propeller RPM in this post a couple of years ago. That relates to the Comanche, but the same applies to the 182 as well.

As I mentioned in the linked post, it seems a bit counterintuitive to me, but perhaps it's a coding compromise or there's some physical real-world explanation that I don't understand. Either way, it's not much of an issue in day-to-day use.

Cheers,
Nick

P.S. Not sure it would generally be appropriate to do a full throttle runup anyway? Mag and prop governor checks are done at around 1800 RPM I believe. Any comments from real-world flyers welcome... :)


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 Post subject: Re: Engine problem?
PostPosted: Sun Dec 10, 2017 6:46 am 
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Some powerplants don't reach their rated RPM in static run, if the engine can't turn the prop fast enough for it to start governing. However, static run-up procedures from 182S/T maintenance manual states:
MM 71-00-01 wrote:
Calculate the average RPM from the recorded RPM figures. The RPM must be between 2350 and 2400 RPM
The RPM is to be recorded with airplane aligned both 90° right and 90° left of the wind direction. So, it should run pretty close to the rated RPM to 'pass', in case of the 182T.

-Esa


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 Post subject: Re: Engine problem?
PostPosted: Sun Dec 10, 2017 7:12 am 
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Nick M wrote:
However, I'm assuming that once you start rolling for the take-off, RPM increases to redline rather quickly?

Yes, it is so. I immediately recalled the same behaviour of the real world counterpart from our local club. That time, the aircraft was grounded right away and a problem with fuel injection was found. This time in the sim, I had fuel injection yellow, too. So I returned and repaired it, but it didn't change a thing.

It wasn't a real static run-up, when I first noticed it. I was making a short-field and applied lots of power at standstill, then increased to full when started moving. And noticed this. Then only I stopped and did a full power absolutely static run-up.


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 Post subject: Re: Engine problem?
PostPosted: Sun Dec 10, 2017 8:15 am 
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AKar wrote:
(...) static run-up procedures from 182S/T maintenance manual states:
MM 71-00-01 wrote:
Calculate the average RPM from the recorded RPM figures. The RPM must be between 2350 and 2400 RPM
The RPM is to be recorded with airplane aligned both 90° right and 90° left of the wind direction. So, it should run pretty close to the rated RPM to 'pass', in case of the 182T.

Yeah, based on this info, the A2A 182T would indeed fail a static RPM check as tested on my installation so good observation Ilya. I won't be grounding mine just yet though! :mrgreen:

Nick


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 Post subject: Re: Engine problem?
PostPosted: Sun Dec 10, 2017 8:52 am 
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Location: Typically hanging around N07, 12N, KLDJ, KCDW
Interesting information. I wonder if this is a slip or a simulation engine limitation that even the external Accusim function cab not work around. This would most definitely be a reason for an immediate rejected takeoff IRL.

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 Post subject: Re: Engine problem?
PostPosted: Sun Dec 10, 2017 8:52 am 
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Nick M wrote:
Yeah, based on this info, the A2A 182T would indeed fail a static RPM check as tested on my installation so good observation Ilya.
On the other hand, TCDS states for propeller limits that:
FAA TCDS 3A13 Rev. 72 wrote:
Static RPM at full throttle: Not over 2400; Not Under 2300 [sic]
Certifying data allows a bit more margin (that is, both readings be under 2350 as long as it was above 2300), albeit it is not an instruction in any sense. Regardless, it suggests that in 182T, the prop should, or should almost, govern at static full throttle.

-Esa


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 Post subject: Re: Engine problem?
PostPosted: Sun Dec 10, 2017 3:06 pm 
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Thanks for the input, everyone! I think it would be interesting to hear from the A2A key developers on the matter.


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 Post subject: Re: Engine problem?
PostPosted: Tue Dec 12, 2017 12:37 pm 
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Ilya,

Esa is spot on in that every airplane is diff. In the case of our airplane, a perfectly tuned Accu-Sim 182 will generate about 2380-90 RPM static. Now keep in mind and accept this as your normal, 100% operating airplane. If you are only making 2378 RPM don't worry or think about it that much, it may mean the engine just isn't working optimally at that time, you may not have perfectly matched engine parts, or things may be getting a little old with some buildup, etc.. In the real world, you would check things and note this.

If one day you find you are only making 2310 RPM then you would want to look further into it. But remember, don't think computer but think analog, real, imperfect as this is the world we live in and how we built Accu-Sim.

Scott.

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