Once more Yo-Yo is RIGHT!

[Anatoli-Kagari9]

I have just forwarded to Yo-Yo the answer I received from a RL, well known 109 demonstration and instructor pilot.

 

He kindly answered all of my questions regarding trim settings, tail heaviness, etc, of 109 models he has flown, including the G4 and G10 variants, and the answers agree pretty much with EXACTLY the behavior we have in DCS's 109, specially if we remove all projectiles, and even not being able to remove the gun pods themselves as well as the MW tank ( this - the MW50 tank issue - will be addressed in a future patch, I guess ).

 

So, again... Yo-Yo IS RIGHT!

 

And, at least in as far as I am concerned, this puts an end to my doubts about this aspect of the K-4 modeling in DCS World.

 

Yo-Yo, although not meant to bash your work, but rather from someone who really cares to know what is modeled in DCS modules is as close to RW performance as possible, my apologies too for having, several times, suggested here at the forums it might be wrong....

 

And, when the "bug" with the always filled MW tank get's solved, it'll be even closer to PERFECTION!

 

BTW, the trim setting I usually need for landing ( -2 or even -3 ) to touchdown at full flaps in a three point position is EXACTLY as described to be the correct use IRL...

Edited January 11, 2016 by jcomm

[fastfreddie]

Why don't you post the questions and answers here for everyone? My only questions about the flight model would of been about the deployment of the slats.

[javelina1]

Good idea, (posting the questions).

 

thanks jcomm, appreciate the info. And yep, yo-yo is da man. :thumbup:

[Anatoli-Kagari9]

I'll ask Klaus Plasa if I am allowed to post here.

 

One other aspect that somehow justified how "slow" the rate at which the trim wheel moves in DCS, compared to other sims, is that it is actually replicating the "tedious" task of turning it, at a pace rather limited by your elbow striking the bulkhead aft of the seat, as Klaus detailed in his answer. Klaus explains that each stroke of trim represents "10-12cm on the rim of the wheel as the left elbow will strike the bulkhead aft of the seat"

 

But I can summarize, for now, what Klaus replied...

 

I was mainly concerned with the need to use such nose heavy trim settings, and about the pitching up moments, and basically his answers pointed out that in the exhibition aircraft he flies even if not loaded with guns and ammunition, MW or external fuel tanks, etc.... which could contribute even more to a tail heavy experience...

 

1) takeoff is usually done at +1, flaps 20º, but as the undercarriage is retracted, the flaps begin to be tediously brought in and as the aircraft gains speed, further nose heavy trim IS required.

 

2) For landing, specially the more empty the fuel tanks are, a good deal of tail heavy trim is needed, but Klaus mentions -2, maybe a bit more - which is exactly what I have to use in DCS with gear down and full flaps ( most of the time -4 ), as Klaus points out needed for a easier 3 point landing...

 

I believe that the problem with the MW50 always being filled has already been reported and will probably get fixed in an upcoming patch.This tank, which can represent, if I'm not wrong, as much as 85Kg ( behind the pilot seat ), contributes even more in our DCS K-4 to the tail heaviness. I am using as much as "- 3" for landing, but i guess that once the MW50 tank can really become empty, a "- 4" setting may become the acceptable one for low fuel loads...

Edited January 12, 2016 by jcomm

[Ghilliedraptor]

I haven't flew the K-4 in a while but I do remember even gentle break inputs could trigger a prop strike. Is this normal?

[eekz]

Could you ask about spin characteristics? :)

[Anatoli-Kagari9]

Could you ask about spin characteristics? :)

 

Exactly what ?

[Yo-Yo]

Could you ask about spin characteristics? :)

 

I already have asked, but modern pilots (as well as Erich, for example) avoid performing it. Erich never encountered deep stall or spin even during the dogfight because of his flying skill.

[Yo-Yo]

I'll ask Klaus Plasa if I am allowed to post here.

 

One other aspect that somehow justified how "slow" the rate at which the trim wheel moves in DCS, compared to other sims, is that it is actually replicating the "tedious" task of turning it, at a pace rather limited by your elbow striking the bulkhead aft of the seat, as Klaus detailed in his answer. Klaus explains that each stroke of trim represents "10-12cm on the rim of the wheel as the left elbow will strike the bulkhead aft of the seat"

 

But I can summarize, for now, what Klaus replied...

 

I was mainly concerned with the need to use such nose heavy trim settings, and about the pitching up moments, and basically his answers pointed out that in the exhibition aircraft he flies even if not loaded with guns and ammunition, MW or external fuel tanks, etc.... which could contribute even more to a tail heavy experience...

 

1) takeoff is usually done at +1, flaps 20º, but as the undercarriage is retracted, the flaps begin to be tediously brought in and as the aircraft gains speed, further nose heavy trim IS required.

 

2) For landing, specially the more empty the fuel tanks are, a good deal of tail heavy trim is needed, but Klaus mentions -2, maybe a bit more - which is exactly what I have to use in DCS with gear down and full flaps ( most of the time -4 ), as Klaus points out needed for a easier 3 point landing...

 

I believe that the problem with the MW50 always being filled has already been reported and will probably get fixed in an upcoming patch.This tank, which can represent, if I'm not wrong, as much as 85Kg ( behind the pilot seat ), contributes even more in our DCS K-4 to the tail heaviness. I am using as much as "- 3" for landing, but i guess that once the MW50 tank can really become empty, a "- 4" setting may become the acceptable one for low fuel loads...

 

You must have asked as well about two more things I already knew the answers: what is the IAS for full nose down trim and TO lack of rudder and his technic of "throttle yaw control" at TO.

MW-50 (I will clarify it completely today) is not a bug of FM but rather of the ME that is fully independant module.

Moreover, we plan to implement proportional load of MW-50 regarding of fuel quantity to avoid tail-heavy CG configuration at low-fuel conditions leaving the opportunity to use MW-50.

[Anatoli-Kagari9]

I already have asked, but modern pilots (as well as Erich, for example) avoid performing it. Erich never encountered deep stall or spin even during the dogfight because of his flying skill.

 

 

Yo-Yo, BTW, THANK YOU for your hard and high quality work and dedication to the DCS ED Modules :thumbup:

[Yo-Yo]

Yo-Yo, BTW, THANK YOU for your hard and high quality work and dedication to the DCS ED Modules :thumbup:

 

Thank you, Sir!

[Echo38]

I'd like to echo that. Above & beyond. : )

[eekz]

Exactly what ?

 

I wounder if he has ever performed a spin on 109 and if yes, what is the technique of starting a spin, and how does the plane behave in a spin.

 

But Yo-Yo has already answered the question.

[Anatoli-Kagari9]

I wounder if he has ever performed a spin on 109 and if yes, what is the technique of starting a spin, and how does the plane behave in a spin.

 

But Yo-Yo has already answered the question.

 

Yep, I believe he did :-)

 

There are indeed many situations we can "test" in the simulator but would probably never be experienced IRL.

 

I remember, for instance, another long time sequence of arguments I initiated a year ago regarding the effects of deflected propwash under heavy x-wind conditions... Of course the situation was one under which a p51d pilot, specially flying one of the real p51s still available for exhibitions would probably not try, but with time I found that indeed the effect modeled in DCS is realistic and makes sense!

[5tuka]

I'm still sceptical about the uppitch momentum at positive pitch angles and would be more than happy if you could share Klaus Plasas statement about it (and other aspects of the 109).

 

I have no doubt that both Klaus and YoYo are well competent in their area of expertise but I somehow don't know why the 109 shows this specific behaviour only in DCS and what's the cause.

 

Otherwise it behaves like a dream and fullfills all of my expectation perfectly.

 

Anyway, hoping you can share your conversation in detail.

Edited January 13, 2016 by 5tuka

[Anatoli-Kagari9]

I'm still sceptical about the uppitch momentum at positive pitch angles and would be more than happy if you could share Klaus Plazas statement about it (and other aspects of the 109).

 

I have no doubt that both Klaus and YoYo are well competent in their area of expertise but I somehow don't know why the 109 shows this specific behaviour only in DCS and what's the cause.

 

Otherwise it behaves like a dream and fullfills all of my expectation perfectly.

 

Anyway, hoping you can share your conversation in detail.

 

5tuka,

 

my conversation with Klaus has not gone beyond what I already mentioned.

 

I might ask him further details, but from his answers my doubts, including the pitching up tendency and hence, as he points out, the need to further set nose heavy trim as the aircraft gains speed justifies the need for fwd stick input inflight.

 

Control deflection and forces are probably low, and we can certainly reproduce it somehow using extensions for our sticks.

[5tuka]

Ah ok so he didnt actually referr to pitch angles but level flight or stick force? Makes sense.

 

I don't know if he can give an answer to what I tried to describe.

[Echo38]

I wounder if he has ever performed a spin on 109 and if yes, what is the technique of starting a spin, and how does the plane behave in a spin.

 

There are indeed many situations we can "test" in the simulator but would probably never be experienced IRL.

 

One thing to bear in mind: even the best simulations in the world can't 100% accurately depict reality, in fields with a high degree of chaos. A few days ago, while idly reading NASA articles about the cosmic-scale motion of galaxies, I saw a NASA image comparing their simulation projection with actual measured results. I just now spent twenty minutes trying to find it again, but I'm afraid I can't remember exactly what the simulation was of. (Cosmic radiation background? Dark flow?) Anyway, with the image in question, the general core of the image was the same in both cases, but the simulation image was much more uniform in distribution, while the actual measured data was highly irregular in its outlying points. This was a NASA simulation, using the best computers & software in the world, and it still was visibly mismatched from the actual results.

 

Simulations involve prediction, but chaos is defined by unpredictability. When you get fields that are sufficiently chaotic, like fluid physics, even the best simulations in the world are going to have a fair margin of error. In most cases, high-fidelity flight simulators have a margin of ~5%, but in particularly complex areas, such as stalls & spins, that margin can be higher. This is especially problematic when it isn't possible to confirm with actual testing.

 

Thus, we cannot expect the stall modelling to be perfect, in DCS or any other P.C. flight simulator, no matter how intelligent & dedicated its creators are. Simply put, simulations differ from actuality in sufficiently chaotic fields. Humanity doesn't possess the capability, at present, to calculate some of this stuff with 100% accuracy. P.C. gaming hardware imposes further limits. I'm very impressed with what we have in DCS, as ten years ago I was telling my friends that I wished for something like this, but thought it could never happen.

 

I'm immeasurably glad that we have a best-in-world simulation of these wonderful antique airplanes. There's no great commercial drive for a simulator like this; if ED were in it for the money, they'd surely have moved to something more popular. This is a work of love, and it's a damn good one.

[otto]

I want to say that the "Ground behavior" Of both 109 and d9 is very very well done and far more advanced than in any other simulation.With the d9 you can actually feel the wheels losing and gaining grip when you slide around the runway sideways.