FDEdev

constant speed prop sound still wrong like in FSX/P3D?

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As the title says. Did they correct the really basic constant speed prop sound bug ?

E.g. X-plane, DCS and even Aerofly FS2 have it correctly simulated.

It's one of the basic things you learn when flying planes with constant speed props:  You can't adjust power by listening to the sound pitch change like with a fixed pitch prop.

If you increase/decrease power there isn't any audible change (as long as you are in the CS prop governing range) IRL. 

 

Talking about old bugs...is the mixture simulation also still wrong?  E.g. the engine fails if not leaned above approx 10000ft?

Edited by J35OE

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Having just seen the first (disappointing) P3Dv4 video I have to bump this, as I really would like to know if DTG fixed this issue.

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You must have watched a different p3d v4 video from me!

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That wasn't exactly an answer to my question, was it.

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To answer your first question: in the Seneca, the prop and engine sounds are independent.  Adjust the prop controls and you'll hear the props pitch up and down.  Change throttle and you'll hear the engine rev up and down.

I haven't had a chance to test other aircraft or the mixture behavior yet.

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So it's as wrong as in FSX/P3D. Well, maybe they are going to fix it, as the Team seems to be pretty determined.  

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5 hours ago, J35OE said:

So it's as wrong as in FSX/P3D.

No, read my response again.  The prop pitch sounds are NOT impacted by power changes.  They fixed it (at least on the Seneca)!

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On ‎23‎.‎05‎.‎2017 at 10:23 PM, MadDog said:

Change throttle and you'll hear the engine rev up and down.

No, it's not fixed.  That's exactly the problem. If you change the throttle on an aircraft with a constant speed prop engine does not rev up because the RPM doesn't change.

(Btw, that's why I don't understand that P3D, which is being sold as an expensive training tool, has exactly the same problem.

Takes a lot away from immersion and realism.

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That doesn't sound right (pun intended!). If the engine rpm increases, the mechanism that controls prop rpm auto-adjusts itself to maintain constant prop speed. Engine "noise" is totally independent from "prop noise."

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Huh?  How can engine RPM differ from prop RPM??? Again, if you increase/decrease throttle, there's virtually no change in sound, at least IRL, x-plane and Aerofly.

Suggest to take a look at this video.  https://www.youtube.com/watch?v=eOXxUApaaWo

Check the part after take off where MP is being reduced from 55" to 45", and immediately afterwards as he reduces prop (and hence engine) RPM.

 

 

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Hmm... An engine running at high manifold pressure is going to make more "noise" than one at low manifold pressure (I admit that using the word "rev" was probably a poor choice; but the 'power output' (exhaust, intake pressure, vibration, etc.) of the engine is definitely going to be audibly different at various power settings).

Another thing to keep in mind is that once a desired prop speed is selected, the governor reacts to changes in engine RPM, not vice versa. For the governor to increase/decrease prop pitch to maintain a constant rpm, it requires a change in rpm from the engine in order to react.  This is evident in your video - when the pilot initially applies throttle, the engine "revs" above the set RPM before the governor kicks in and starts reducing it back.  Admittedly, the audio technique in P3D, FSW, etc. is not 100% correct; but it would require a ton of logic in the sound system to get just right.

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23 minutes ago, MadDog said:

1.when the pilot initially applies throttle, the engine "revs" above the set RPM before the governor kicks in and starts reducing it back. 

2. it would require a ton of logic in the sound system to get just right.

1.That's a totally different situation where the prop isn't within its governing range. Please wind forward to approx 50sec where Kermit  reduces MP.

2.Not at all. With many FSX turboprops this is working like IRL, e.g. in the Carenado B1900D.

X-plane (not exactly famous for it's advanced sounds) and even Aerofly FS2 (which is much more a fun simulator than an expensive 'training device') have it done correctly. 

 

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5 minutes ago, J35OE said:

With many FSX turboprops this is working like IRL, e.g. in the Carenado B1900D.

We weren't talking about turboprops... that's really comparing apples and oranges.

I stand by my original statement: An engine running at high manifold pressure is going to make more "noise" than one at low manifold pressure.

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9 minutes ago, MadDog said:

1.We weren't talking about turboprops... that's really comparing apples and oranges.

2.I stand by my original statement: An engine running at high manifold pressure is going to make more "noise" than one at low manifold pressure

1.You are taking this example out of context. It's not about the difference between piston and turboprop engines.

It's about the 'ton of logic in the sound system to get just right' you mentioned and I'm just writing that this system is already in place and works with many turboprops.

2. So why is there no difference between 55" and 45" MP ?   (btw. when reducing MP from 45" to 30" there's no change either) 

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22 hours ago, J35OE said:

Huh?  How can engine RPM differ from prop RPM???

The prop is not always connected directly to the engine's crankshaft, but is sometimes driven via a gear reduction system, and prop speed is controlled by either a mechanical or hydraulic governor to maintain a selected speed by varying the pitch of the blades.

The engine spins (just like a car engine) based on fuel flow and the air mixture through the venturi, or fuel pressure controlled by the injector system in the case of a fuel-injected engine. Rather than measuring engine RPM, instead engine power is measured/reported in terms of manifold pressure.

See: http://www.boldmethod.com/learn-to-fly/aircraft-systems/how-a-constant-speed-prop-works/

 

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1 hour ago, n4gix said:

The prop is not always connected directly to the engine's crankshaft, but is sometimes driven via a gear reduction system, and prop speed is controlled by either a mechanical or hydraulic governor to maintain a selected speed by varying the pitch of the blades.

Even if the prop is not always connected directly to the engine's crankshaft and a reduction gear is involved, it's still a fixed ratio!

To include geared engines it looks like I have to rephrase my statement:

Propeller RPM can not be controlled independently from engine RPM, regardless if it's a constant speed or fixed pitch propeller.

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