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Phantom88

P-51 On Final Approach

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1st day buy for me...

 

I already own the MLADG 109 G-2, a great add-on which is being brought as close as possible to the real thing, but I was missing a good p51 for XpX.

 

I need to believe it's possible to have in XpX as good a fdm as what I got with DCS, and I do believe in that judging from the tweaking I made to the 109 G-2 :-)

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The sounds aren't it's best feature :-/

 

Basic tests to perform ( aerodynamics ):

 

- should show neutral pitch stability for pitch up perturbations from trimmed state

- should show positive pitch stability for pitch down perturbations from trimmed state

 

These two are basic and mandatory, otherwise it isn't a p51...

 

Then, many more follow, including the accelerated stall characteristics due to the supercritical airfoil, and so on...

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Hello Jose,I think the Merlin Engine sounds are very well done from what I can hear in these short video's,Khamsin Studios has a proven track record for creating very realistic Warbirds for X-Plane....I expect this to exceed those great Aircraft. :smile:   

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Basic tests to perform ( aerodynamics ):

 

- should show neutral pitch stability for pitch up perturbations from trimmed state

- should show positive pitch stability for pitch down perturbations from trimmed state

 

Do you have more info on that? Docs, etc.?

 

In theory, for small perturbations and in the cruise regime, flight dynamics should have a linear behaviour, and hence act symmetrically for pitch up or down.

 

EDIT: Ok, I've come to the conclusion that the simmetric behaviour is probably restricted to only very small perturbations in pitch. Evidently, for the P51 even a few degree of pitch perturbation, produce non linear effects and hence an asymmetric behaviour.

 

2nd EDIT: Ok, made further research. Technically speaking, it's not correct to say that the p51 has neutral pitch stability for pitch up and positive pitch stability for pitch down (that would have not made sense).

 

What happens instead, is that its pitch stability decreases with the increase in lift coefficient (and hence AoA), becoming lower at higher AoA's and higher at lower AoA's.

 

So, what happens is that when you pitch up _in a certain AoA range_, you're going through the shallower part of the pitch stability curve, while when you pitch down, you're going through the steeper part of the curve.

 

Of course the final effect is the one you mentioned, that is a higher pitch stability when pitching down and a lower one when pitching up.

 

However, as you can see from this chart, if the perturbations are confined in an Cl range of about 0.60 - 1.20, or alternatively in a range of 0.00 - 0.40, the slope of the power-on pitch stability curve is constant, and hence the behaviour for pitch up and pitch down should be symmetrical.

 

YDsaxLF.jpg

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Tom, you were really a luck guy :-)

 

I still start my A2A P51s, but am willing to test this one in XPX :-)

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Tom, you were really a luck guy :-)

 

I still start my A2A P51s, but am willing to test this one in XPX :-)

 

I think a wrong test . Oh crap you went back to FSX

 

I see something lacking in that video and yes that I am actually comparing to the DCS flight of any aircraft and not the aircraft.

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I think a wrong test . Oh crap you went back to FSX

 

I see something lacking in that video and yes that I am actually comparing to the DCS flight of any aircraft and not the aircraft.

 

Not back to FSX, but I have some beta-testing to do :-)

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Patrick, and others who can answer :-)

 

Assuming you own them all :-), I mean - DCS's P51d, FSX's A2A P51d and now this Khansim P51d, how would you rank them, flight dynamics wise ?

 

In the videos I see a weird behavior of the ball in the turn coordinator, almost all of the time the instrument is focused...

 

With an empty fuselage tank, from trimmed level flight, how does it behave when you pull the stick and then rturn it to neutral ?  And the way around when you push the stick and return to neutral from level trimmed flight ?  

 

Do you notice the difference in turns with a filled fuselage tank - reversal of pitch input necessary due to rearward CoG ?

 

Any other comments on the way it "flies" appreciated :-)

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Patrick, and others who can answer :-)

 

Assuming you own them all :-)

 

[...]

 

Any other comments on the way it "flies" appreciated :-)

 

+1: I'd very much welcome some proper information about that as well!

:smile:

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Assuming you own them all :-), I mean - DCS's P51d, FSX's A2A P51d and now this Khansim P51d, how would you rank them, flight dynamics wise ?

 

I was watching a stream of the Khansin Mustang last night, and it looked pretty good, Having flown the real Mustang though, I thought the roll rate was a little high. To be fair, I also thought the A2A's were as well. Here's a sample of the real one

 

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I was watching a stream of the Khansin Mustang last night, and it looked pretty good, Having flown the real Mustang though, I thought the roll rate was a little high. To be fair, I also thought the A2A's were as well. Here's a sample of the real one

 

Agree, in the video the Khamsin P51 seems to achieve a roll rate of about 180 deg/sec, whereas the real P51 should have a max roll rate of about 90 deg/sec. Given that the roll rate is one of the most basic parameters, It's unlikely they put much effort for the rest of its flight dynamics .

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