Simviation Forum - Prop Rotation Speed

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Prop Rotation Speed (Read 1168 times)

Mar 31^st, 2004 at 12:49pm

Skittles Offline
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N769JC: "Isn't simulating
stimulating?
JAQ: Westover Field, CA (O70)

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Hello,

I found out that if I adjust the starter torque, I can adjust the amount of time from the starter being engaged to the engine kicking over (Pistion Engine). Cheesy

I have it synchronized with the Prop_Blurred effect taking affect.

The problem, during spin down, the prop stops spinning before the sound of the engine stops. Tongue

What, if anything, can I adjust to adjust the spindown time?

Thanks,

Joe

What do computers and air conditioners have in common?
They both will work perfectly, until you open windows.

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Reply #1 - Apr 1^st, 2004 at 12:04am

Milton Offline
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Props forever!

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prop_tc may be of some help ....

For a fairly quick stop, a few seconds, try .01. Increase the number toward 1.0 to spin down more slowly.

Milton&&Dash 7, Aero Commanders, Howard 500, D18S, Spartan, XP47J, Beechcraft A28 (Grizzly)

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Reply #2 - Apr 1^st, 2004 at 2:24am

Skittles Offline
Colonel
N769JC: "Isn't simulating
stimulating?
JAQ: Westover Field, CA (O70)

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Posts: 837

Well Milton, no such luck.
I tried many numbers from .001 to 10. No change. The propeller stops in about 3.5 seconds everytime.
Just in case, here is my Prop section. Maybe there is an association with another setting? ???

[propeller] thrust_scalar = 1.0 //Propeller thrust scalar propeller_type= 0 //0=Constant Speed, 1=Fixed Pitch propeller_diameter= 9 //Propeller Diameter, (feet) propeller_blades= 3 //Number of propeller blades propeller_moi= 6.9 //Propeller moment of inertia beta_max= 30.0 //Maximum blade pitch angle for constant speed prop, (degrees) beta_min= 0 //Minimum blade pitch angle for constant speed prop, (degrees) min_gov_rpm= 500.0 //Miminum governed RPM prop_tc= .1 //Prop time-constant gear_reduction_ratio= 1.0 //Propeller gear reduction ratio fixed_pitch_beta= 20.0 //Fixed pitch angle of fixed pitch prop, (degrees) low_speed_theory_limit= 80.0 //Speed at which low speed theory becomes blended in (feet/second) prop_sync_available= 1 //Prop synchronization available? 0=FALSE, 1=TRUE prop_deice_available= 1 //Prop de-icing available? 0=FALSE, 1=TRUE prop_feathering_available= 1 //Prop feathering available? 0=FALSE, 1=TRUE prop_auto_feathering_available= 1 //Prop auto-feathering available? 0=FALSE, 1=TRUE min_rpm_for_feather= 100.0 //Minimum RPM for prop feathering beta_feather= 22.5 //Feathering pitch angle (degrees) power_absorbed_cf= 0.2 //Coefficient of friction for power absorbed by propeller defeathering_accumulators_available= 0 //Defeathering accumulators available? 0=FALSE, 1=TRUE prop_reverse_available= 0 //Prop reverse available? 0=FALSE, 1=TRUE minimum_on_ground_beta= 30 //Miminum pitch angle on ground, (degrees) minimum_reverse_beta= 0 //Minimum pitch angle in reverse, (degrees) rotation = -1, 1 //-1=CCW, 1=CW

Thanks for the suggestion though.

What do computers and air conditioners have in common?
They both will work perfectly, until you open windows.

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Reply #3 - Apr 1^st, 2004 at 3:29am

SilverFox441 Offline
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Mississauga, Ontario, Canada

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Change the propeller_moi= 6.9 //Propeller moment of inertia entry.

To be safe record the original value before fooling around.

If memory serves higher values increase run down time and lower values decrease it.

Steve (Silver Fox) Daly

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Reply #4 - Apr 1^st, 2004 at 2:38pm

Milton Offline
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Props forever!

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Not sure of your aircraft but there are some things I would change in those settings that will make a difference in a small constant speed prop:

beta_max= 45.0
beta_min= 8
min_gov_rpm= 700.0
beta_feather= 82.5
power_absorbed_cf= 0.8

Milton&&Dash 7, Aero Commanders, Howard 500, D18S, Spartan, XP47J, Beechcraft A28 (Grizzly)

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Reply #5 - Apr 2^nd, 2004 at 3:19am

Skittles Offline
Colonel
N769JC: "Isn't simulating
stimulating?
JAQ: Westover Field, CA (O70)

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Posts: 837

SilverFox, That's the ticket. Set it to 15 and it's perfect.

Milton, Don't know what it is you told me to do, but my "aircraft" handles a little better.

Thanks to both of you,

Joe

What do computers and air conditioners have in common?
They both will work perfectly, until you open windows.

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