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Old 05-20-2019, 06:27 AM   #121
grafspee
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engine no tourqe??
when i fly slow at approach and add to much throttle to get some speed i am all over the place if i dont react correctly

Last edited by grafspee; 05-20-2019 at 10:13 AM.
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Old 05-20-2019, 08:00 AM   #122
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Quote:
DCS P-51 has no torque

DCS Bf-109 has some torque but not enough
Well that's the crux of the matter right there. You claim there's no torque, while I'm seeing signficant amounts of it, which compels me to think there's something wrong with your installation. Because if there really was none across the board, I'd sure as hell notice it too.
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Old 05-20-2019, 10:13 AM   #123
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Quote:
Originally Posted by msalama View Post
Well that's the crux of the matter right there. You claim there's no torque, while I'm seeing signficant amounts of it, which compels me to think there's something wrong with your installation. Because if there really was none across the board, I'd sure as hell notice it too.
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Old 05-26-2019, 01:06 PM   #124
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Quote:
Originally Posted by Ala13_ManOWar View Post
Do you mean "engine torque", not the other three effects that we usually sum up as torque but aren't engine torque per se?


S!
That is, indeed, what I mean. In the P-51 there are some yaw effects that happen at various times but nothing that resembles the torque produced by the engine/propeller.

The only instance where it is vaguely correct is below 80 mph in a pure vertical climb, when the aircraft briefly rotates about its long axis when at full power.

This may be a canned effect. It certainly appears that it is.

Engine torque is a constant force countered by the ailerons. Rudder is a secondary method but not nearly as effective since torque produces a rolling moment.

So for a given torque level, there must be a equal and opposite control force. The lower the airspeed the greater the control DEFLECTION required to achieve the balancing control FORCE and vice versa.

At some airspeed, full deflection is required to counter the torque force.

This things are true for ANY single engine propeller driven aircraft.

So it follows, that any power change requires a change in aileron deflection and any airspeed change also requires a change in aileron deflection.

In the DCS P-51 one can go stop to stop with the throttle and the aircraft will not demonstrate any significant rolling moment. It does some yawing which produces a slight roll but that roll stops after about 30 degrees and the aircraft just wallows around a bit.

It is very well known that slamming the throttle to full at slow airspeed in a P51 produces a very dramatic rolling moment.

The pilot, in a panic, applies full aileron. This is the classic setup for an adverse yaw event exacerbating the the leftward torque roll with predictably bad results.

The DCS P51 does not exhibit any of this behavior and will only drop a wing at slow speed if you actually enter an aerodynamic stall.
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Old 05-26-2019, 01:07 PM   #125
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Quote:
Originally Posted by msalama View Post
Well that's the crux of the matter right there. You claim there's no torque, while I'm seeing signficant amounts of it, which compels me to think there's something wrong with your installation. Because if there really was none across the board, I'd sure as hell notice it too.
The problem is you mistake some yaw effects for engine torque. And it doesn't seem like you are willing to consider that possibility.
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Old 05-26-2019, 01:56 PM   #126
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Quote:
Originally Posted by pmiceli View Post

Again, it is quite simple physics. The motor is turning a large propeller. Newton's third law is operative.



Engine torque does not produce yaw. It is a rotational force translated into yaw when the aircraft is in contact with the earth, through the gear.

(...)


DCS P-51 has no torque



DCS Bf-109 has some torque but not enough.



Are they in a ratio that basically reproduces relative performance? Maybe



Are they correct? Not even close.


So where did you fly a real life P-51D and BF.109 K4 as you seem to have experienced the yaw effect and torque in the planes in real life, considering your statements.
In the Sim at least, I feel a considerable torque along the longitudinal axis if I get near stall speed and induce too much torque when pushing the throttle...
How much torque was there in the real life plane you flew and how the hell did you survive the experience? Really interested in a real life BF.109 K4 pilots input on that.
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Old 05-26-2019, 06:34 PM   #127
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Originally Posted by NineLine View Post
The documents you list were just a few of the many used, but also weigh more than your hunches. You can question all you want, but they aren't worthy questions if you have no fact to back up your arguments.
Yep, and I just had the time to try recreating the test from the "document ( Diving_Test_109F_W.Nr.9228_ger_eng.pdf )" presented and while started reading through the German originals I noticed two interesting facts, already.
1) The plane used was an Bf.109 F with G Wings and no mentioning of the engine used.
2) according to the document the plane was tested in a dive starting at 10.7 Km MSL and an overall weight (Fluggewicht) of 2,900 kg.
Before we discuss any of these document's "findings" and “adapt" them to the simulated BF.109 K4, I would like to ask everyone to recreate these conditions, especially the WEIGHT.
Our simulated K4 has an empty(!), as in NO FUEL weight of 6395 lbs or 2900,72 Kg... unless they glided the plane into a dive and landed it afterwards, either the weight of "our" K4 is wrong, what I doubt, or the F used in the tests has a different weight/is a different aircraft/likely has a different engine. Anyway with a different weight/different CoG etc. , the whole comparison is pretty much useless, I guess.
I wonder, why none of our "forum specialists" here with "engineering background" did not point that out, as they sure must have thoroughly read them papers before comparing the results to the simulated K4 ?!
Or am I missing something, that explains the weight difference?
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Old 05-26-2019, 10:10 PM   #128
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Because there is no problem and the following quotes make it clear that discussing anything aircraft related in this thread is a waste of time. How does aircraft weight in the fuselage influence high speed roll characteristics, just interested?! 7-8 kN are 700-800 kg/m^2 in your mind? God almighty... Stickforces of 300-400 kg? Jesus!


Quote:
Originally Posted by shagrat View Post
If you want to tell us, that it's totally easy to pull the stick against a force of roughly 7-8 KiloNewton (700-800 kg/m2) at 450 km/h against at least half a squremeter of elevator, with both hands, cramped into the cockpit with your knees bent and against the pedals, we can discuss.


Let's assume the elevators give you a counter force of "just" 350 - 400 Kg, I consider a bit of "stiffening" pretty realistic... but that's just my interpretation of the original charts and I may be wrong.

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https://forums.eagle.ru/showthread.php?t=200423
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Old 05-26-2019, 10:36 PM   #129
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Originally Posted by rel4y View Post
Because there is no problem and the following quotes make it clear that discussing anything aircraft related here is a waste of time. 7-8 kN are 700-800 kg/m^2 in your mind? God almighty... Stickforces of 300-400 kg? Jesus!
Well, not exactly in my mind, it's what the unit KiloNewton stands for: 1,000 Newton which is roughly a force equal to 102 kg (per squaremeter).
You can Google KiloNewton.
I roughly halfed the force to 300 to 400 kg as the elevators together are more 50*100 cm sized or a bit less, so even if we make it only a quarter of the measured 7 to 8 kN it's still 150 to 200 kg.
And you did not answer how you did set the K4 to 2900 kg gross weight in DCS, when conducting your "verification of the flight model based on the paper you provided"? So you make assumptions based on research that's obvious made with a different plane, to make a point while trying to throw smokescreens to cover this little discrepancy and waste our time?
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Old 05-26-2019, 10:42 PM   #130
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Originally Posted by pmiceli View Post
That is, indeed, what I mean. In the P-51 there are some yaw effects that happen at various times but nothing that resembles the torque produced by the engine/propeller.

The only instance where it is vaguely correct is below 80 mph in a pure vertical climb, when the aircraft briefly rotates about its long axis when at full power.

This may be a canned effect. It certainly appears that it is.

Engine torque is a constant force countered by the ailerons. Rudder is a secondary method but not nearly as effective since torque produces a rolling moment.
You are absolutely far from the real prop physics and PRACTICE. The real world physics sometimes is more complex than a school book or an old vanilla Il-2 FM. If you take a look at the trim diagrams for the most powerful WWII fighters you could see that small aileron input is used only at very low IAS and the PRIMARILY counteracting factor is RUDDER.
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