Engine idle rpm and others

NachtPiloten

NachtPiloten

Kurier auf Stube...pauke!
Staff member
How do you adjust the idle rpm? I use Airwrench, but the entry for the idle rpm does not effect the idle speed in the game. In CFS2 years ago there was an entry to adjust the throttle efficiency and this is no longer supported? Oh, this is for CFS3. Also - how do you get Airwrench to recognize that the plane in a bi-plane - the radio buttons don't seem to work ion the dimensions tab?
 
I don't use CFS3; I usually stick to CFS2 and FSX. I usually set my Max & Min Design MP's apart by a factor of 10. For example, if you have a P-51 with a Merlin that can get up to 65 PSI (approx), then set your low MP at 6.5. See what your idle RPM is and adjust up or down accordingly.

There is usually a line in the .cfg file that specifies "max_rated_rpm = XXXX". You might try inserting a
line that specifies "min_rated_rpm = XXXX" or "idle_rpm = XXXX" and see if it works. If you have the SDK kit for the aircraft configuration, it may tell you whether this info can be specified in the file.
 
Take a look at this...

Its not part of the engine. Look at the prop.

entry 510 in AirED. Governed RPM min...

or you can change it in the CFG

EXAMPLE:

[propeller]
propeller_type=0
propeller_diameter=10.416700
propeller_blades=3
propeller_moi=28.004372
beta_max=65.000000
beta_min=15.000000
min_gov_rpm=450.000000
prop_tc=0.010000
gear_reduction_ratio=2.096000
fixed_pitch_beta=20.000000
low_speed_theory_limit=80.000000
prop_sync_available=0
prop_deice_available=0
prop_feathering_available=0
prop_auto_feathering_available=0
min_rpm_for_feather=70.000000
beta_feather=88.500000
power_absorbed_cf=0.900000
defeathering_accumulators_available=0
prop_reverse_available=0.000000
minimum_on_ground_beta=0.000000
minimum_reverse_beta=0.000000

The area in RED should do what you want.

As far as being reconized as a Bi Plane. in the .airfile look at entry 319.

As far as airwrench goes I'm not sure. I don't have the full version.

I hope that helps.
 
Quote (As far as being reconized as a Bi Plane. in the .airfile look at entry 319.)

My .air file templates say 319 is a boolean for Stall Warning, so no idea how to make an air file & a cfg make it see a biplane except for wing area, which really mucks things up because it affects the calculation for aspect ratio.
Keith
 
Blood_Hawk23 said:
Its not part of the engine. Look at the prop.

entry 510 in AirED. Governed RPM min...

or you can change it in the CFG

EXAMPLE:

[propeller]
propeller_type=0
propeller_diameter=10.416700
propeller_blades=3
propeller_moi=28.004372
beta_max=65.000000
beta_min=15.000000
min_gov_rpm=450.000000
prop_tc=0.010000
gear_reduction_ratio=2.096000
fixed_pitch_beta=20.000000
low_speed_theory_limit=80.000000
prop_sync_available=0
prop_deice_available=0
prop_feathering_available=0
prop_auto_feathering_available=0
min_rpm_for_feather=70.000000
beta_feather=88.500000
power_absorbed_cf=0.900000
defeathering_accumulators_available=0
prop_reverse_available=0.000000
minimum_on_ground_beta=0.000000
minimum_reverse_beta=0.000000

The area in RED should do what you want.

As far as being reconized as a Bi Plane. in the .airfile look at entry 319.

As far as airwrench goes I'm not sure. I don't have the full version.

I hope that helps.
Click to expand...
===============================
OK. If I understand my relationships correctly, then the calculated product of min_gov_rpm (for the PROP) and gear_reduction_ratio should give us the (minimum) ENGINE RPM:

i.e. (450 rpm) x (2.096) = 943 RPM

Again, one can adjust accordingly to get the desired figures.
 
glh said:
===============================
OK. If I understand my relationships correctly, then the calculated product of min_gov_rpm (for the PROP) and gear_reduction_ratio should give us the (minimum) ENGINE RPM:

i.e. (450 rpm) x (2.096) = 943 RPM

Again, one can adjust accordingly to get the desired figures.
Click to expand...

Hopefully it gets you close. Let me know if that worked for you.
 
Dev One said:
Quote (As far as being reconized as a Bi Plane. in the .airfile look at entry 319.)

My .air file templates say 319 is a boolean for Stall Warning, so no idea how to make an air file & a cfg make it see a biplane except for wing area, which really mucks things up because it affects the calculation for aspect ratio.
Keith
Click to expand...

You know your right. In the newer version of AirEd I have the same thing. Now in my older version of aired 319 is listed as --- monoplane type?=faulse(0)

The only other entry that I can think of is in 1101
under
airframe type=8249 or 6968

Those numbers are used for all of the bi-planes in my WWI install 6968 is used on mostly the small scouts. 8249 is used on the larger bombers.

Thats all I've got.
 
Idle is somewhat determined by the bottom two entry points of the internal friction per cylinder curve in the .Air file. You might try the idle RPM mechanical efficiency scalar in the piston engine section of the Cfg. file, though I have never used this possible way.

T
 
Min gov RPM only affects the lowest speed at which a constant speed prop is capable of governing the engine speed. This is usually around 1200-1400 RPM. Having too low a governed RPM is a bit (not exactly) like starting your manual transmission off in top gear.

Cheers: T
 
With respect to the AirWrench biplane question, the 'Wing Configuration' is not an option, it's what the flight model looks like according to the wing dimensions entered. Use it as a sanity check for your inputs.

It's calculated as follows:

1) Calculate 'Max Wing Area' by multipling 'Wing Span' by 'Wing Root Chord'.

2) If 'Max Wing Area' divided by the entered 'Wing Surface Area' is:
A) less than 1, then the aircraft is a monoplane
B) more than 1 but less than 2, then the aircraft is a biplane
D) more than 2 but less than 3, then the aircraft is a triplane

In CFS3, air file section 500 is not used. It was replaced by entries in the aircraft.cfg file.

Section 319 is a stall warning available flag. I think this was still used in CFS3 but it replaced by aircraft.cfg 'stall_warning' in FS9.

Idle speed adjustment is complicated. Just about anything that affects the engine or prop (air file sections 508, 509, 511, 512, turbo charged or not, constant speed prop or fixed pitch, etc.) affects the idle speed, and note that the same things that affect the idle speed also affects whether the engine will start.
 
With a low idle speed the engine may want to quit unless the throttle is cracked till it has run a bit. My experience with real round engines sort of goes along with this, too low an idle also fouling the plugs.
 
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