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Effect of Propeller on Ruder


Hobel

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too weak in DCS ?

I have the feeling that it has little to very weak effects at slow speeds and especially with the Hammerhead maneuver.

 

It's not that I can't get a hammerhead in DCS, it just doesn't feel quite as nice as in some illustrations, the example in this video or others

I am aware that it is not a WW2 aircraft and that can make a difference.

 

 

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Maybe weight and size do matter here.

This guy mastered this, so perfect, like on rails.


Edited by grafspee

System specs: I7 14700KF, Gigabyte Z690 Aorus Elite, 64GB DDR4 3600MHz, Gigabyte RTX 4090,Win 11, 48" OLED LG TV + 42" LG LED monitor

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@Hobel NEED EVIDENCE . is the first thing you are going to hear.

 

Personally I have stated the same thing in the past only to be massively discredited by lurking keyboard vultures, benighted in most cases. 

Some DCS fm's actually SCREAM this, provided the fact that you have some hours in actual aircraft controls....   


Edited by fapador
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vor 29 Minuten schrieb fapador:

@Hobel NEED EVIDENCE . is the first thing you are going to hear.

That's why I posted it here and not in the "bug report area".

 I wanted to know what other users had to say about it🙂

I just tested the Yak52/P47/Spitfire in the free trial runs and on the first few tries it worked almost perfectly, the rudder feels much more plausible at slow speeds or in a Hammerhead

with D9,K4 and P51 does not go so beautiful.


Edited by Hobel
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1 hour ago, fapador said:

@Hobel NEED EVIDENCE . is the first thing you are going to hear.

 

Personally I have stated the same thing in the past only to be massively discredited by lurking keyboard vultures, benighted in most cases. 

Some DCS fm's actually SCREAM this, provided the fact that you have some hours in actual aircraft controls....   

 

Funnily enough, you only care about the real world experience that suits you. Whenever you heard of another pilot telling you it's fine and the problem is yours you turn off hearing  🤣 .

"I went into the British Army believing that if you want peace you must prepare for war. I believe now that if you prepare for war, you get war."

-- Major-General Frederick B. Maurice

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Different aircraft are... different.

That these even needs to be said seems surprising, but...

Rudder authority at zero airspeed will vary based on a host of factors including:

  • Rudder area
  • Rudder profile
  • Rudder mass balance profile
  • Vertical stabiliser area
  • Incidence of Vertical stabiliser (often off-set to compensate for torque in WW2 era fighters)
  • Rudder position in propellor slipstream
  • Moment arm of rudder (distance from CoG)

Given the even superficial huge differences in the format of the vertical flying surfaces seen in the WW2 aircraft is it any wonder that some have better rudder authority than others?

As for the example video, that's an aeroplane specifically designed for aerobatics, ergo one assumes that excellent rudder authority at low to zero airspeeds is a requirement.

Not so with WW2 fighters.

More often than not the overriding concern is speed; larger vertical tail surfaces causes more drag, so the designers calculate the minimum vertical tail surface area to keep the aircraft just positively stable directionally. Else you are slowing the aircraft down.

As we see so often, their calculations are not quite enough to account for either (a) the increases in HP that comes with a new improved engine or (b) for the instability introduced in reduction of the vertical area behind the CoG (cutting down the rear fuselage to install bubble canopies, for example). Because of this we see after the fact retrofits of tail strakes/fins or enlarged vertical stabs and/or rudders because they had initially hoped to avoid the necessity of increasing the vertical fin area and thus reduce the effectiveness of that HP increase or form drag decrease by reintroducing more drag inducing empennage area.

 


Edited by DD_Fenrir
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4 hours ago, Ala13_ManOWar said:

Funnily enough, you only care about the real world experience that suits you. Whenever you heard of another pilot telling you it's fine and the problem is yours you turn off hearing  🤣 .

No its not fine. Hate to break it for ya but in fact some Fm's in DCS aren't even ballpark...  In fact,  my suspicions have been confirmed through  discussions with pilots, both high rank militants and  civil aviation people... , not with some random enthusiasts in cyberspace saying otherwise...

 

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6 hours ago, DD_Fenrir said:

Rudder authority at zero airspeed will vary based on a host of factors including:

Rudder authority at zero airspeed is actually zero and only propwash comes to play....  unless you are trying to speak of the low airspeed regime in general..

where authority  is actually directly affected by the way propwash interacts with the vertical surface, which in turn is  an equation of all  the design factors you state and the additional examined speed.

 

6 hours ago, DD_Fenrir said:

Given the even superficial huge differences in the format of the vertical flying surfaces seen in the WW2 aircraft

And no I disagree. though the Video depicts an extra 300  and indeed they are design differences when compared to  WWII bird's, most symmetrical and some assymetrical airfoils used on aircrafts today were actually designed in the 1920's. Such an example is the Air Tractor AT-802 first flown in 1990 which uses airfoil designs from 1920's.

Also  from quick comparison. though I am pretty sure surface area will differ: 

Extra 300 rudder deflection = 30 degrees

BF109 K-4 rudder deflection = 32 degrees

BF109 E-4 rudder deflection = 34 degrees

Spitfire MkIx rudder deflection = 28.5 degrees

P51D rudder deflection = 30 degrees

The conclusions are yours.


Edited by fapador

Obsessed with FM's

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vor 5 Stunden schrieb DD_Fenrir:

That these even needs to be said seems surprising, but

I am more than aware of these parameters.

But such a summary may not be missing in this topic of course, thanks for that 🙂

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2 hours ago, fapador said:

No its not fine. Hate to break it for ya but in fact some Fm's in DCS aren't even ballpark...  In fact,  my suspicions have been confirmed through  discussions with pilots, both high rank militants and  civil aviation people... , not with some random enthusiasts in cyberspace saying otherwise...

 

Well, then I'm a pilot myself, as per usual I know many pilots just because I happen to be among them, and the ones I've talked to about this game are really happy with it, either military pilots who have flown several of the types recreated, or ATPLs who only might have flown IRL a couple at best, but still they all say the same. This "game" features things I'd never seen on a pc "game", name it simulator or not, ever before and those things go way farther than any other software company had even tried in the past, current times or foreseeable future.

It's not perfect mate, how could it be, it's still a PC game trying to show us a hint of what it's like to fly one of these machines, but, what do you know other than DCS coming even remotely close to this attempt? So, stop complaining about everything and enjoy the actual gorgeousness this "game" has to offer. I'm not blind, I know there're issues here, but generally speaking a few smaller details can't stop me from enjoying a experience I couldn't have IRL (fighter jets? warbirds? come on), but even though I haven't flown any of the models we have here (not even Yak-52, 400$ per flight hour are to blame), in my limited experience, this "game" models things never, ever seen before in a commercial simulation, and that's a thing either, I became a pilot after having 30 years of simulation gaming experience, thus I know what it takes in both worlds. "FM's aren't even ballpark" 🤦‍♂️ 🤣🤣 , really, I don't know what you talking about.

Allow me to rephrase so perhaps you get it, "the best FM's we've ever seen on a PC game, featuring things which apparently are just a kind of magic and obscure wizardry for every other developer out there, which despite being a pc game after all still is a really great and accurate representation of what is really like to fly a real aeroplane, aren't even a ball park because I'm suspicious and I say so". Clearer now?

 

P.S.: Don't get me wrong, because I know many pilots I also know the ones who usually only have experience in their training simulators, and they still to this day in the twenty first century think those are just useless entertaining games (aided by the fact that training simulators use to be quite ugly and lacking detail, fine). But, no matter the pilots they are, they haven't the faintest about modern simulation and what can be done just at home, so their own bigotry about this being a useless game don't allow them to know better, let along enjoy such a thing like DCS or any other game out there is. The day they discover how wrong they were usually a new world opens up to them. Anyhow, those can say whatever condescending thing to "wannabe gamers" they consider everybody, but since they have no idea about what is and what is not a real simulation like DCS is and I happen to have my own 30 years simulation experience before PPLing, I trust my own criteria here which also concurs with many other pilots open minded enough and/or with their own experience in simulation besides RL to know better than the former 😉.

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"I went into the British Army believing that if you want peace you must prepare for war. I believe now that if you prepare for war, you get war."

-- Major-General Frederick B. Maurice

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14 hours ago, fapador said:

Rudder authority at zero airspeed is actually zero and only propwash comes to play....  unless you are trying to speak of the low airspeed regime in general..

where authority  is actually directly affected by the way propwash interacts with the vertical surface, which in turn is  an equation of all  the design factors you state and the additional examined speed.

 

And no I disagree. though the Video depicts an extra 300  and indeed they are design differences when compared to  WWII bird's, most symmetrical and some assymetrical airfoils used on aircrafts today were actually designed in the 1920's. Such an example is the Air Tractor AT-802 first flown in 1990 which uses airfoil designs from 1920's.

Also  from quick comparison. though I am pretty sure surface area will differ: 

Extra 300 rudder deflection = 30 degrees

BF109 K-4 rudder deflection = 32 degrees

BF109 E-4 rudder deflection = 34 degrees

Spitfire MkIx rudder deflection = 28.5 degrees

P51D rudder deflection = 30 degrees

The conclusions are yours.

 

So, let me get this straight, given all the parameters I outlined that will govern how effective an aircrafts rudder will be at Zero airspeed and power-on (which I would have thought was implicit given the nature of the manoeuvre being discussed), you choose one where the values for the various aircraft are similar and believe that disproves my theory?

Furthermore, you present it as a fait accompli, as if this information is somehow a revelatory three-pointer, as if this implicitly proves that all aircraft should stall turn with equal acumen.

Wow.

Excuse Me Reaction GIF by Mashable

 

Then you say most aerofoil profiles are from those 1920's....

THERE WERE MANY DIFFERING AEROFOIL PROFILES FROM THE '20s.  IT DOES NOT MEAN ALL AIRCRAFT USE THE SAME ONE.

What about the rudder surface area? I notice you pay lip-service to this aspect when it seems fairly critical given the progressive increase in fin and rudder area of various aircraft sub-variants to cope with increasing power and directional stability issues as the war progresses.

What about the rudder pedal foot forces? What about the thrust to weight ratio? What about the torque? What about the yaw-roll coupling behaviour of the airframe? What about the presence of any aileron surface area in the propeller slipstream?

What if your aircraft is too powerful to stall turn without torque rolling out of it under power, yet with power off there is insufficient rudder area to provide enough yaw authority at that low airspeed to perform the manoeuvre?

I notice you avoid addressing this particular issue:

Quote

As for the example video, that's an aeroplane specifically designed for aerobatics, ergo one assumes that excellent rudder authority at low to zero airspeeds is a requirement.

Not so with WW2 fighters.

More often than not the overriding concern is speed; larger vertical tail surfaces causes more drag, so the designers calculate the minimum vertical tail surface area to keep the aircraft just positively stable directionally. Else you are slowing the aircraft down.

How do you get around this particular fact - not opinion, fact.

Who are these pilots you keep referencing; what are the names? What hours do they have in Mustangs/Spitfires/109s/etc. What gives their apparent criticism any legitimacy?

Personally, I suspect you troll here in an attempt to discredit DCS. Your posting history is littered with bitter, accusational and tacitly insulting criticism of EDs but the arguments therein lack the knowledge, education or authority to do so in a manner that stands any actual scrutiny.

I'm at a loss at what you wish to achieve; unless it's to get DCS turned into some faux arcade game version of itself.

 


Edited by DD_Fenrir
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@DD_Fenrir Extra 300 Rudder Area : 0.51 m^2

                        BF-109 K-4 Rudder Area : 0.57 m^2

                        P51D Rudder Area : 0.96 m^2

                        Spitfire MkIx Rudder (Pointy type) Area : 0.99 m^2

 

It actually doesn't take much... Any serious pilot,  with experience should be able to confirm  that WWII birds in DCS are notoriously weak in Yaw and there is NO way they handled or handle like that...

I am not saying they should hammerhead like an extra 300 but being almost 4x times weaker in yaw authority  is definitely not right...


Edited by fapador

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30 minutes ago, fapador said:

@DD_Fenrir Extra 300 Rudder Area : 0.51 m^2

                        BF-109 K-4 Rudder Area : 0.57 m^2

                        P51D Rudder Area : 0.96 m^2

                        Spitfire MkIx Rudder (Pointy type) Area : 0.99 m^2

 

 

That is tremendous area in Extra 300 compare to weight and size of warbirds.

Bf-109 is the best 5 times more power almost same rudder area no wonder it is hard to keep it streigh on take off, and every time when tail lifts bf-109 wants to turn in to grass.


Edited by grafspee

System specs: I7 14700KF, Gigabyte Z690 Aorus Elite, 64GB DDR4 3600MHz, Gigabyte RTX 4090,Win 11, 48" OLED LG TV + 42" LG LED monitor

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17 minutes ago, grafspee said:

That is tremendous area in Extra 300 compare to weight and size of warbirds.

Precisely. It may be smaller but it physically has to move less mass… unless fapador thinks they weigh the same also… 🙄

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No I dont think they weigh the same. but Extra 300 notably  shorter so smaller/less moment arm...

 

Weak rudder is common on all DCS warbirds, whoever think its ok is completely benighted, fooled or mislead.

12 minutes ago, DD_Fenrir said:

Precisely. It may be smaller but it physically has to move less mass… unless fapador thinks they weigh the same also… 🙄

HAHA you are the one who said to look at the surface areas... Now you see that its indeed smaller you change your argument...


Edited by fapador

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Summary:

Extra 300 Rudder Area : 0.51 m^2                                      Extra 300 rudder deflection : 30 degrees

BF-109 K-4 Rudder Area : 0.57 m^2                                   Bf109 K-4 Rudder deflection: 32 degrees

 P51D Rudder Area : 0.96 m^2                                            P51D Rudder deflection : 30 degrees

 Spitfire MkIx Rudder (Pointy type) Area : 0.99 m^2         Spitfire MkIx Rudder deflection: 28.5

 

Compared to Bf109 K-4, Extra 300 is 4 times lighter than Bf109 K-4,  However it has smaller moment arm as its shorter by 2 meters.

The conclusions are always yours.

 


Edited by fapador

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Bf-109 400% mass of Extra 300

Bf-109 128% length of extra 300

 


Edited by grafspee

System specs: I7 14700KF, Gigabyte Z690 Aorus Elite, 64GB DDR4 3600MHz, Gigabyte RTX 4090,Win 11, 48" OLED LG TV + 42" LG LED monitor

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Problem is here, that Bf-109 is on spot at take off behavior, it does exactly as bf pilots describe it, increasing rudder authority from prop wash would ruin that, take off in bf-109 would be pice of cake. I remember pilot saying that if you are not prepared for nose swing in bf-109 when tail lifts it will turn in to the grass how it would be possible if rudder from prop wash could wing plane at 0 speed with ease. That thing make no sense for me.

System specs: I7 14700KF, Gigabyte Z690 Aorus Elite, 64GB DDR4 3600MHz, Gigabyte RTX 4090,Win 11, 48" OLED LG TV + 42" LG LED monitor

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Aside from Extra 300, Perhaps we should compare against a more suitable example.... the T6 Texan...

Yeah DCS Warbirds rudder  authority is still miles away from being adequate enough....

 

The conclusions are yours as always...


Edited by fapador

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On 6/27/2022 at 6:36 PM, DD_Fenrir said:

Given the even superficial huge differences in the format of the vertical flying surfaces seen in the WW2 aircraft is it any wonder that some have better rudder authority than others?

As for the example video, that's an aeroplane specifically designed for aerobatics, ergo one assumes that excellent rudder authority at low to zero airspeeds is a requirement.

Not so with WW2 fighters.

Oh😮 look that. Wait what? T6 Texan hammerheads very  alike an Extra 300.... 🤯🤯🤯😱😱😱


Edited by fapador
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