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Old 08-16-2018, 10:42 PM   #1
peter
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Default Propeller RPM lever question

Just recently having replaced my warthog throttle I am remapping all my axis commands. Have they removed the Mustang Prop Rpm Lever command? What changed? I dont see it in the controls menus. Also I have recently returned to DCS after a brief hiatus so bear with me please. Thank you.
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Old 08-16-2018, 11:57 PM   #2
jackdaw
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Look under axis commands. its called Engine rpm setting
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Old 08-17-2018, 10:43 AM   #3
bbrz
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With the prop lever you are changing the prop pitch, and this in turn changes engine RPM.
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Old 08-17-2018, 12:10 PM   #4
DD_Fenrir
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Quote:
Originally Posted by bbrz View Post
With the prop lever you are changing the prop pitch, and this in turn changes engine RPM.
No you aren't. You are asking the Propeller Constant Speed Unit to try to maintain a certain RPM setting; the unit then adjusts the blade angle to try to match that setting whatever the variations in power, airspeed and altitude.

Semantics, maybe, but it's an important distinction that should be made.
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Old 08-17-2018, 01:17 PM   #5
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Quote:
Originally Posted by DD_Fenrir View Post
No you aren't. You are asking the Propeller Constant Speed Unit to try to maintain a certain RPM setting; the unit then adjusts the blade angle.
Suggest to re-read my post since this is exactly what I wrote. By moving the prop lever, the constant speed unit changes the prop pitch/blade angle.
It's not about what you are asking the CSU to do, it's about what's actually happening.
This has nothing to do with semantics.

Last edited by bbrz; 08-17-2018 at 01:20 PM.
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Old 08-18-2018, 01:58 AM   #6
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Fenrir is correct
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Old 08-18-2018, 03:50 AM   #7
bbrz
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I don't get it, but since both of you are talking about semantics it might be a language issue.
If I'm e.g. pulling the prop lever back to achieve a lower engine RPM, the CSU actually increases the propeller blade angle to achieve this new target.

Last edited by bbrz; 08-18-2018 at 03:56 AM.
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Old 08-18-2018, 06:39 PM   #8
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Quote:
Originally Posted by bbrz View Post
I don't get it, but since both of you are talking about semantics it might be a language issue.
If I'm e.g. pulling the prop lever back to achieve a lower engine RPM, the CSU actually increases the propeller blade angle to achieve this new target.
"The throttle controls manifold pressure (MP) and (indirectly) pitch of the prop. Increasing
throttle increases the manifold pressure (the pressure of the air/fuel mixture going to the
engine) and the prop tries to turn faster. The prop controller then resists faster RPM by
increasing the "bite" of the blades in the air. This increased pitch and angle of attack of the
blades causes more thrust, but also causes more drag, resisting an increase in RPM. In a
sense, throttle only increases the torque of the engine, and then the prop governor
increases the pitch of the blades to produce more thrust and drag. This happens quickly and
automatically, so no change in RPM is noticed.
So, the throttle controls the MP/engine torque/prop pitch, and the prop lever regulates
engine/prop RPM."

Courtesy of: http://www.enstoneflyingclub.co.uk/f..._operation.pdf
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Old 08-18-2018, 07:03 PM   #9
bbrz
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Quote:
Originally Posted by zcrazyx View Post
1.The throttle controls manifold pressure (MP) and (indirectly) pitch of the prop.
2. the throttle controls the MP/engine torque/prop pitch...
3. ...and the prop lever regulates engine/prop RPM."
It's not about what the CSU does or what happens when you increase/decrease throttle/MP.

1. That's exactly the point, indirectly.
2. See point 1. Throttle controls MP and indirectly prop pitch.
3. By moving the prop lever you are regulating the RPM indirectly (through the CSU) by directly changing the prop blade pitch.

http://www.boldmethod.com/learn-to-f...ed-prop-works/

Last edited by bbrz; 08-18-2018 at 07:10 PM.
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Old 08-18-2018, 11:36 PM   #10
Frederf
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Nope, directly you are changing the spring tension on the balance of the dynamical system regulating RPM. The thing that causes the counterweights to remain in place is the RPM and only the RPM. By changing the balance of the centrifugal system the control variable is the RPM and only the RPM.


With a new equilibrium in place the direct result is RPM will change. The fact that the pitch will change to achieve this new RPM equilibrium is incidental. It would work exactly the same if the feedback mechanism was something other than pitch change (e.g. if a valve opened that increased throttle).
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