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Old 07-17-2018, 11:10 AM   #71
bbrz
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Quote:
Originally Posted by jcomm View Post
Ah, and BTW, torque should also be countered using RUDDER, not ailerons
IRL in a (full power) vertical climb you need the rudder and the ailerons to keep/correct the wing position. With the DCS TF-51 I need only rudder and no ailerons.

But, after flying the TF-51 and the FR 109 extensively I have to admit that (apart from the discussable torque/low AoA interaction) the TF-51 feels much more like a real airplane than the 109 in FSX and I do concur with jcomm when he says that DCS (don't have IL since many years) flight models are way ahead of other flightsims.

edit: corrected weird quote error

Last edited by bbrz; 07-17-2018 at 12:06 PM.
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Old 07-17-2018, 11:28 AM   #72
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I did not post that sentence, how is my name there in your quote?
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Old 07-17-2018, 12:36 PM   #73
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Quote:
Originally Posted by bbrz View Post
IRL in a (full power) vertical climb you need the rudder and the ailerons to keep/correct the wing position. With the DCS TF-51 I need only rudder and no ailerons.

But, after flying the TF-51 and the FR 109 extensively I have to admit that (apart from the discussable torque/low AoA interaction) the TF-51 feels much more like a real airplane than the 109 in FSX and I do concur with jcomm when he says that DCS (don't have IL since many years) flight models are way ahead of other flightsims.

edit: corrected weird quote error
That's why I love this old post by EvilBivol and link and share it a lot for others that are new to flight sims or just learning what to know more without getting into CFD modelling etc. The guy's here are trying, with some limitations, more than any other sim's, to go as deep as possible with the FM modelling, the aircraft feel more alive to me and the choppers way more than other sims.

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Originally Posted by EvilBivol-1 View Post

Again, it's ultimately a model and cannot be completely correct or account for every physical phenomenon, but we try to go as deep as possible in terms of real-time modeling and as wide as possible in terms of covering physical effects within reasonable limits of time and money. Otherwise we could work on any one model endlessly, which is probably what some of the devs would like to do.

Read the full post here
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Old 07-17-2018, 01:02 PM   #74
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+1
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Old 07-17-2018, 01:33 PM   #75
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Again, it's ultimately a model and cannot be completely correct or account for every physical phenomenon, but we try to go as deep as possible in terms of real-time modeling and as wide as possible in terms of covering physical effects within reasonable limits of time and money. Otherwise we could work on any one model endlessly, which is probably what some of the devs would like to do

I fully agree with these considerations, and let's not forget that the flight sensations that return the aircraft in DCS are unique, that is the result of an excellent work in compliance with the conditions reported by EvilBivol-1 and does not seem to me a thing to little for a consumer simulator.



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Old 07-17-2018, 04:09 PM   #76
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I was interested, how the Bf-109 would fare in the same experiment:


Vertical climb 1.8 ATA prop auto (rpm 2800) (MW-50)

00:35 IAS: 98 km/h / Pitch: 87 / AoA: -4,5 - stable - very slow right roll due to full right rudder
00:36 IAS :79 km/h / Pitch: 86 / AoA: -6,5 -stable -same
00:37 IAS :60 km/h / Pitch: 83 / AoA: -10,4 -stable -same
00:38 IAS :40 km/h / Pitch: 79 / AoA: -20,1 -rotation starts
00:39 IAS :30 km/h / Pitch: 77 / AoA: -27 -rotation accelerates
00:40 IAS :20 km/h / Pitch: 72 / AoA: +121 -rotation accelerates (much faster now then TF-51)
00:42 IAS :-46 km/h / Pitch: 65 / AoA: -148 -rotation around twice as fast as TF-51 very roughly 220 deg/second

Rotation at twice TF-51 speed continues, falling backward until nose falls down at 00:48 (and white smoke from the engine), then rotation slows and stops


No track this time, but view counts are low anyway...
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Old 07-17-2018, 04:40 PM   #77
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What I see here after these experiments is the following:


- Torque is modelled BUT for some reason the roll tendencies around the longitudinal axis are very weak or non existent even in the low speed, low dynamic pressure regime up until the point the aircraft exceeds stall AoA, then there is unstoppable rotation along the longitudinal axis due to torque


- Torque is unique to the aircraft (Bf-109 spins faster than TF-51).


I think, we could agree on, that the forces acting on the airframe by the relative flow at speeds of 50 km/h is quite low (whatever is the direction).


Also the difference in speed is very low between between the torque roll and no torque roll range (60 to 40 km/h, and 80 to 50)


Both the TF-51 and the Bf-109 seems to behave following the exact same pattern, even though they are quite different beasts.



Altogether it seems: Stall AoA acts as a trigger: If AoA > stall---> torque roll, if AoA<stall--->no torque roll
Edit: The problem: why is there no tendency to rotate left around the longitudinal axis before stall AoA is reached in the very low dynamic pressure regime.



Writing an effective bug report about this will be quite difficult.... IF there is a bug at all...

Last edited by HWasp; 07-18-2018 at 09:56 PM.
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Old 07-17-2018, 05:33 PM   #78
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Quote:
Writing an effective bug report about this will be quite difficult....
Could you try regardless since you've dug into it already?
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Old 07-17-2018, 08:38 PM   #79
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Quote:
Originally Posted by HWasp View Post
What I see here after these experiments is the following:


- Torque is modelled BUT is only effective once the aircraft is over stall AoA (positive or negative does not matter)


- Torque is unique to the aircraft (Bf-109 spins faster than TF-51).


I think, we could agree on, that the forces acting on the airframe by the relative flow at speeds of 50 km/h is quite low (whatever is the direction).


Also the difference in speed is very low between between the torque roll and no torque roll range (60 to 40 km/h, and 80 to 50)


Both the TF-51 and the Bf-109 seems to behave following the exact same pattern, even though they are quite different beasts.



Altogether it seems: Stall AoA acts as a trigger: If AoA > stall---> torque roll, if AoA<stall--->no torque roll


Writing an effective bug report about this will be quite difficult....
Reminds an old joke:
A scientist trying to find where the bug's ears are place it on a table and screams. The bug runs away. Then he rips off one of bug's leg and screams at it again - bug runs away. He rips off the second leg and screams at the bug - bug runs away. As he rips off the last leg and screams - bug does not run. So the scientists writes an article and states that the bugs have ears on their legs.
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Ничто так сильно не ранит мозг, как осколки стекла от разбитых розовых очков (С) Me

Last edited by Yo-Yo; 07-17-2018 at 09:46 PM.
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Old 07-17-2018, 09:25 PM   #80
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That moment when you think there is something wrong with the FM and Yo-Yo comes in and says, NOPE!

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