FSX N2_rated_thrust ISDT ATR question

[chriszoepound]

hello all.. lately ive been flying and fiddling around with the Isdt ATR 72-212 merged with the F1 Atr panel

These are my engine and propeller stats right now..they currently provide great engine performance for me..I can cruise at 23000 feet at about 210-220 knots. with throttle in the green at about 60-70% and cruise mode selected:
[GeneralEngineData]
engine_type =5
Engine.0 =5.400, -10.150, -2.000
Engine.1 =5.400, 10.150, -2.000
fuel_flow_scalar =1.20900
min_throttle_limit =-0.25000

[propeller]
thrust_scalar=0.875000
propeller_type=0
propeller_diameter=13.20000
propeller_blades=6
propeller_moi=248.15892
beta_max=46.00000
beta_min=16.50000
min_gov_rpm=15100.00000
prop_tc=0.00400
gear_reduction_ratio=17.00000
fixed_pitch_beta=0.00000
low_speed_theory_limit=90.00000
prop_sync_available=1
prop_deice_available=1
prop_feathering_available=1
prop_auto_feathering_available=1
min_rpm_for_feather=500.00000
beta_feather=80.00000
power_absorbed_cf=0.90000
defeathering_accumulators_available=0
prop_reverse_available=1
minimum_on_ground_beta=1.00000
minimum_reverse_beta=-18.00000

[TurbineEngineData]
fuel_flow_gain=0.2000
inlet_area=1.00000
rated_N2_rpm=40816.00000
static_thrust=105.00000
afterburner_available=0
reverser_available=1
afterburner_throttle_threshold=0.00600
ThrustSpecificFuelConsumption=0.00600
AfterBurnThrustSpecificFuelConsumption=0.00600

[turboprop_engine]
power_scalar=1.00000
maximum_torque=11066.13759
max_rpm_mechanical_efficiency_scalar=1.0
idle_rpm_mechanical_efficiency_scalar=1.0
max_rpm_friction_scalar=1.0
idle_rpm_friction_scalar=1.0

rated_n2_rpm, static thrust, and thrust scalar...have all been modified to accommodate a FS2004 tweak that provides a realistic feathering effect only available on ISDT ATR aircraft..(

)..but it doesnt work well in FSX using the same modified parameters(propellers spin too slowly in FSX)....After much fiddling around I've discovered that for the feathering tweak to work in FSX.. rated_n2_thrust has to be increased to about 70816...unrealistic value that leaves the engines almost powerless..but it gives a very cool realistic feathering effect.

My question is...if at current values(rated_n2=40816, static thrust=105, thrust_scalar=0.875, and fuel_flow_scalar=0.2) the ATR responds and flies like a charm(imo)..If i place Rated_n2=70816...what else would i have to modify..and to how much...so that the ATR responds as good or near as good as it responds now??Is it as simple as a math equivalence..between lets say static thrust and rated_n2 ??(example, if 105=40816, then X=70816 ??(lol i wish it was that simple but any help would be much appreciated))

I plan on releasing my ISDT ATR 212 aircraft.cfg and soundpack both modified especially for those who use this aircraft with the Flight1 ATr panel merge..but i would like to hae realisitc feathering modified into that aircraft.cfg as well..

 

[WarpD]

Do you own the rights to the ISDT ATR? You can not take someone else's work and release it as your own... no matter how modified.

 

[chriszoepound]

Do you own the rights to the ISDT ATR? You can not take someone else's work and release it as your own... no matter how modified.

Im not releasing a modified model nor am i asking for money or credit. for anything I do...
I always share credit with the rightful owner in anything i upload.and if possible I ask for permission to use and modify models...
In this case though all credit is to the ISDT team for the ATR packages theyve released...I would just be an uploading my minor modifications to a freeware site for anyone who wants to try them...
In this case the ISDT team is no where to be found nowadays..At least not in clear sight..thus permission cant be asked for nor granted or rejected..BUT...seeing that i'm not benefiting economically in any way from this...and I of course give them their rightful credit where due....I sincerely see no problem in releasing my modification...but if it really is a problem.....Instead of sharing the entire .cfg file..i can share a text file where i show what was tweaked in the aircraft.cfg of the ISDT ATR
If someone from the ISDT team emails me stating their discontent with my modifications..I would immediately remove my work from the internet..
Can you help me with that N2_rated_thrust question by chance?-- All I need is to figure that outso i can have a cool realistic feathering effect..

 

[WarpD]

The aircraft.cfg is a text file and is easily covered by copyright law because of that. Handing it out to others, however benign on your part is still a violation of the copyright of the product. It simply shouldn't be done.

I can't comment on the behavior... as I get turboprops to feather without any of this approach. If the prop won't feather, there's something else wrong... not the N2 value.

 

[chriszoepound]

The aircraft.cfg is a text file and is easily covered by copyright law because of that. Handing it out to others, however benign on your part is still a violation of the copyright of the product. It simply shouldn't be done.

I can't comment on the behavior... as I get turboprops to feather without any of this approach. If the prop won't feather, there's something else wrong... not the N2 value.

Ok then seeing the aircraft.cfg can cause an issue, I'll make a text file indicating how to tweak it then..

The aircraft feathers from a flight dynamics point of view...but actually seeing the feathering effect is what i want..just like in the video above..I've figured out I can do it in the ISDT ATR 72-212 in FSX by increasing the N2_rated_thrust value to about 70816(unrealistc, but it gives that realistic feathering visual effect)...But doing this makes the aircraft very slow...as nothing else is modified...

What I want to know.. and maybe someone here hopefully can help me identify..is... with N2_rated_thrust at 70816..What else would I have to modify in the aircraft cfg..so that the plane wont be so slow..thats all...Im basically asking for equivalent values that should be modified..for that N2_rated_thrust=70816..

 

[WarpD]

That's not a thrust rating... it's just an RPM value. Now... the reason you're seeing speed issues deals with the gear reduction ratio. But I suspect when you fix that your feathering issue will appear again.

The visual feathering is based on the blades beta and I'm here to tell you if that's not right... there's something else that's wrong... an unrealistic N2 max RPM isn't going to actually fix it... only mask it.

 

[Roy Holmes]

N2_rated_thrust does not exist as a recognized FDE parameter, so the question can not be answered. A turboprop engine's thrust is minimal and plays an insignificant part in its performance. The thrust comes from the propeller, not the jet pipe.
I'm a bit unclear why you want to use a FS2004 tweak in FSX. It looks like you are unhappy with the prop animation. How do you know when the prop is feathered, what data are you recording?
Fiddling with parameters rarely creates a provable result.
Roy

 

[chriszoepound]

That's not a thrust rating... it's just an RPM value. Now... the reason you're seeing speed issues deals with the gear reduction ratio. But I suspect when you fix that your feathering issue will appear again.
The visual feathering is based on the blades beta and I'm here to tell you if that's not right... there's something else that's wrong... an unrealistic N2 max RPM isn't going to actually fix it... only mask it.

N2_rated_thrust does not exist as a recognized FDE parameter, so the question can not be answered. A turboprop engine's thrust is minimal and plays an insignificant part in its performance. The thrust comes from the propeller, not the jet pipe.
I'm a bit unclear why you want to use a FS2004 tweak in FSX. It looks like you are unhappy with the prop animation. How do you know when the prop is feathered, what data are you recording?
Fiddling with parameters rarely creates a provable result.
Roy

Lol i've been writing n2_rated_thrust all this time.. im sorry.. i really wanted to say what you said rated_n2_rpm.. smh... Ok sincerely im lost now...Is the visual feathering based on increased or decreased beta??

WarpD by blades beta do you mean the beta max and beta min values? ok im a bit lost now..lol..Is the visual feathering effect based upon increased beta or decreased beta values?

Roy, yes i'm a bit unhappy with it..because..realistic feathering ive always heard was never realistically modeled into fsx...so seeing that this tweak for the ISDT aTR was available for FS2004...seeing its the same model..I decided to try it in FSX...to see if it would hopefully recreate the same feathering effect..but sadly it didnt..the blades move too slowly...Tweaking around a while i ended up using the values i have posted at the beginning..even though the propellers in feather move too slow..because performance is fine with those values...but now im trying once again to get that feathering effect..All It needs is for the blades to spin a little bit faster..I achieved that by changing Rated_n2_rpm from 40816 to 70816..but when this is done...the feathering effect looks nice..but the airplane becomes unflyable..it becomes slow..and..engine sounds basically disappear..The sounds are there but the rated_n2_rpm is so unrealistically high that at full thrust they sound like low ground idle..lol. so i came here to see if you guys who are experts could help me.

 

[chriszoepound]

How do you know when the prop is feathered, what data are you recording?
Fiddling with parameters rarely creates a provable result.
Roy

Well I know the prop is feathered...because im using the F1 aTR panel..and im using its throttle panel.. I move RPM to Start and Feather..it does its feathering thing..then i move RPM levers to AUTO for taxi and cruise....OVRD for Takeoff and final approach.... ..All I want is for the blades to visually spin a little bit faster during feather..i want the realistic visual feather effect for the ISDT ATR 72-212 in FSX..and putting rated_n2_rpm at 70816 or higher does it..but in the process screws up the engine performance..So im trying to figure it out...Maybe the solution is in the .air file..

 

[Roy Holmes]

A lot of instrumented test was done in a thread called FSXA prop feathering. Try a search for it
One of the points made was that a feathered prop produced no thrust, positive or negative. What the animation does is something else.
IIRC there were three animation states, stopped, slow and blurred in FS2004 and two in FSX which could make a visual difference.
Roy

 

[chriszoepound]

A lot of instrumented test was done in a thread called FSXA prop feathering. Try a search for it
One of the points made was that a feathered prop produced no thrust, positive or negative. What the animation does is something else.
IIRC there were three animation states, stopped, slow and blurred in FS2004 and two in FSX which could make a visual difference.
Roy

So This feathering effect that only is visible on the ISDT ATR is this a form of "stopped" animation that im seeing?? Or is it just a glitch? I'll take a look at that FSXA prop feathering thread

 

[Roy Holmes]

It was http://www.fsdeveloper.com/forum/threads/prop-feathering.436888/

Roy

 

[Roy Holmes]

It was http://www.fsdeveloper.com/forum/threads/prop-feathering.436888/

A piston engine will stop when it is no longer active and the prop is feathered because of the compression resisting rotation. I'm unsure whether a turboprop will stop when feathered, my guess would be not since there is little drag.
Roy

 

[Heretic]

The aircraft.cfg is a text file and is easily covered by copyright law because of that. Handing it out to others, however benign on your part is still a violation of the copyright of the product. It simply shouldn't be done.

Really? Well, in that case, shut down all flightsim libraries and sue the contributors since even repaints do contain third party content from the original developer, i.e. textures - or parts thereof - not adapted to the livery.

 

[WarpD]

Really.

 

[chriszoepound]

It was http://www.fsdeveloper.com/forum/threads/prop-feathering.436888/

A piston engine will stop when it is no longer active and the prop is feathered because of the compression resisting rotation. I'm unsure whether a turboprop will stop when feathered, my guess would be not since there is little drag.
Roy

Hey Roy I kinda dont get what that has to do with this case...How would you create the visual effect of a PW127 engine feathering and link it to the RPM levers actually being in Start&Feather??, like shown in the videos above..

 

[Roy Holmes]

I looked at the videos and am non the wiser about what you want to achieve.
First, the only reason to feather a propeller is to prevent it windmilling and creating drag after the engine itself has failed. A draggy windmilling engine will increase the minimum control speed when under assymetric flight conditions. It may render the airplane uncontrollable.
There is absolutely no utility in feathering an engine when stationary on the ground.
So, what do you expect to see?
You have, in FSX, three states for propeller animation, STILL, SLOW and BLURRED. Typically STILL applies when the percent Prop RPM is 6.25 and less, BLURRED is 12.5 and greater and SLOW is between 6.25 and 12.5. A feathered prop should fall into the STILL category and exactly what it does depends on the animation in the model, which you can not alter unless you have the source code.
Classically a feathered engine/prop is stopped with the blades rotated (beta) to present as little drag as possible. As I said earlier I am not familiar with turboprops and it may be that they slowly rotate after feathering. And they would only do that in the air or a strong wind on the ground.

.How would you create the visual effect of a PW127 engine feathering

Please describe what you think that visual effect would be.
Roy

 

[taguilo]

As I said earlier I am not familiar with turboprops and it may be that they slowly rotate after feathering. And they would only do that in the air or a strong wind on the ground.

That's correct Roy.

I am also not sure about what the OP is trying to achieve. If propeller parameters are ok, then it is a matter of prop animation in the model and therefore not possible to modify by altering values in aircraft.cfg

However, if props spin too slow, perhaps increasing mixture will help to increase the rate and improve visual effects.

Tom

 

[Heretic]

Really.

Well, looks like that's it then. Shutting down all my projects.

 

[chriszoepound]

I looked at the videos and am non the wiser about what you want to achieve.
First, the only reason to feather a propeller is to prevent it windmilling and creating drag after the engine itself has failed.

Please describe what you think that visual effect would be.
Roy

I want to achieve precisely what is seen in the tweak video..but in FSX...Using the same parameters as in the FS2004 prop tweak video..in FSX makes the propellers spin too slow..As taguillo said..maybe increasing mixture will help with that.. If not I would probably need the ISDT ATR source files ..and the chances of obtaining those are almost 0..So the feathering idea would be done right there.. On regional turboprops equipped with PW12X series engines..feathering is a step you cant get around..when starting up the engine..you move the RPM levers to Start&Feather..and then to Auto or Override..when shutting off the engines or taxiing to gate the engines a feathered then shut down too..

On a class trip to a military air base the last academic year..We took a look at the CASA 295s (which use the PW127G, The ATR 72-212 uses PW127F) in the hangar undergoing A and D check maintenance, and the same question about feathering came up( why is the engine designed to be feathered first?),and the answer the engineer gave was: the engines have to be started in feather to avoid the aircraft possibly putting anybody in front in serious danger during start-up, like whoever is dealing with the GPU for example. And apart from that I already knew this but in class we learned that in case of engine failure, the propellers are automatically(with autofeather) or manually supposed to be put in the feather position for drag reduction. But i mean thats pretty obvious, the feather position provides smoother aerodynamic flow...

Im just trying to take advantage of that ISDT ATR glitch..or whatever it is that makes the engine actually appear visually feathered in FS2004, and get it to work in FSX(and still be able to fly her).