Question re. 109s handling

[Reflected]

I did notice that when you use the rudder the plane starts bouncing left and right like a pendulum, even at high speed. I'm not a specialist at flight physics, but i'm pretty sure that the rudder should be somewhat stabilised from the air flow and not go left-right-left-right like it was in a vacuum with minimal inertia.

 

Exactly my thoughts, and my real life experience (although not on 109s)

[pixelshader]

This needs to be taken very seriously or will never end !!!

 

I just call of the developers.

And we understood each other very well , Despite a big language barrier , they use all his well learned politesse ,

Why....

Study my video and you get the aswer... listen carefully the end of the video, that's what's missing from the 109

 

http://youtu.be/MoRG4PmTC0A

 

 

 

 

.

 

Deactivating its hyperdrive?

[Gambit21]

So much for remaining silent.

[LukeFF]

This needs to be taken very seriously or will never end !!!

 

I just call of the developers.

And we understood each other very well , Despite a big language barrier , they use all his well learned politesse ,

Why....

Study my video and you get the aswer... listen carefully the end of the video, that's what's missing from the 109

 

Dude, give it a rest already. 

[Sternjaeger]

yes Mustang, I appreciate your passion, let's the devs do their job, I'm sure they're aware of these issues and they'll address them accordingly.

[AX2]

Deactivating its hyperdrive?

Or allow the hyper drive, 

 

So much for remaining silent.

I feel bad with myself

 

Dude, give it a rest already. 

Darth Vader never wrong !

 

But ... If RoF is perfect. 

What was one of worst mistake of development in BoS, ...only maybe....

Spending too much money on FM, wasting time in 1000 equations for FM??? ......mmmmmmmmmm , I dont know...

We'll have a million fights FM, BUT the solution ( fix ) to all this is already done in RoF

But well, the humanity never learns. 

 

https://www.youtube.com/watch?v=0cDEPlBnQ4g

 

 

 

yes Mustang, I appreciate your passion, let's the devs do their job, I'm sure they're aware of these issues and they'll address them accordingly.

 

 

 

Ok. ends here

Edited May 31, 2014 by Mustang

[FuriousMeow]

You just don't know what you're talking about Mustang. There is no perfection, this is being done on a home computer. Simulators for Boeing require many computers in parallel to simulate as best they can, but its not perfect. There is no perfect. Its a computer program. We're lucky if this is within 80% of simulating reality. Fact is, it is more likely closer to 50%, because there are so many variables that have to be accounted for a $100 program still won't be able to simulate them all.

Edited May 31, 2014 by FuriousMeow

[AX2]

You just don't know what you're talking about Mustang. There is no perfection, this is being done on a home computer. Simulators for Boeing require many computers in parallel to simulate as best they can, but its not perfect. There is no perfect. Its a computer program. We're lucky if this is within 80% of simulating reality. Fact is, it is more likely closer to 50%, because there are so many variables that have to be accounted for a $100 program still won't be able to simulate them all.

+1.000.000

 

Furious Meow you missed my point  .

 

Agree ...nothing is perfect ofcourse, becouse your and my desktop PC is not a NASA computer, For that simple reason nothing is perfect.

Then if you develop a game, you must give a the buyers tools to make them feel happy.

 

In my f.....g country, You must  multiplied  the prices of amazon and ebay X 3, ... some times more, by taxes and custom clearances,  I swear you.

 

Why  I will need to spend 2500 dollars on warthog joystick, rudder pedals,  and extensions to the joystick and more ?,  I just want to play the game in 109.

 

Most buyer's market, are only  boys who want to play the game, spending a reasonable amount of money

If they make a game for the elite only, they will lose buyers ,and 80% of profit. 

Maybe only maybe.... Fly 109 requires, so most of the guys on the market today can not buy.

Because of that I like RoF Response curves, this is the best fix ... And no one will mourn about the 109 FM.. maybe.. only maybe..

 

 

 

 

 

Edited June 1, 2014 by Mustang

[FuriousMeow]

I'm sorry, I think something is lost in the translation. I apologize and I do not understand what you mean.

[LukeFF]

You just don't know what you're talking about Mustang. There is no perfection, this is being done on a home computer. Simulators for Boeing require many computers in parallel to simulate as best they can, but its not perfect. There is no perfect. Its a computer program. We're lucky if this is within 80% of simulating reality. Fact is, it is more likely closer to 50%, because there are so many variables that have to be accounted for a $100 program still won't be able to simulate them all.

 

Indeed. In one of Jason's ROF "reports" he made about visiting 777 Moscow, Petrovich demonstrated to him a flight model that is far more advanced than what we have now, but the problem is that current PC technology cannot run it that efficiently, so for now we have the next best thing, which is still (of course) very good. 

 

EDIT: ah, here it is: http://www.simhq.com/_air13/air_464c.html

 

He really knows his stuff and he showed me just a part of the code that makes up one component of the ROF flight and damage engine. It was 3500 lines of code! To say our flight and damage models are simplistic is absurd. This is why we cannot release planes at a more rapid clip. To do so would cause a reduction in the quality of our flight models and we don’t think anyone wants that. He showed me some of the dev tools, charts and resources he uses to test his creations and I watched him trouble shoot a bug with the DFW. He is an amazing engineer who does not get as much credit as he deserves.

 

Matter of fact, he has created a new flight and damage model that is 10x more accurate than the current model. The only problem is current computers cannot run it effectively in game yet and multiplayer would be crushed due to its complexity and accuracy. The demo I saw was eye-popping cool. To say we are hampered by today’s hardware and internet bandwidth is an understatement. Maybe someday it will be possible to be deployed.

 

Edited June 1, 2014 by LukeFF

[Conveen]

Damn when I read all this here we are so lucky that the developers dont give the already castrated german planes plastic ammo

[Nonolem]

Didn't find the original post. Copy/past from Reflected answer above :

 

kiershar, on 29 May 2014 - 20:04, said:

I did notice that when you use the rudder the plane starts bouncing left and right like a pendulum, even at high speed. I'm not a specialist at flight physics, but i'm pretty sure that the rudder should be somewhat stabilised from the air flow and not go left-right-left-right like it was in a vacuum with minimal inertia.

 

I am not pilot myself, but I can do physics and the 109 behaviour seems to me to not be so absurd. Maybe exaggerated, but not absurd.

The rudder is very effective, and when you use it, the plane responds quikly and turn around the vertical axis, masking a wing of the airflow. So the wing on the side of the turn is dropping.

The moment of inertia around this axis is important, because the fuselage is long and heavy. The vertical surfaces tend to push back the plane in its original direction with a certain angular speed -> big kinetic moment. The plane is crossing the equilibrium position and is going to the other side with a consistant angular speed, and will do it again and again. The plane is oscilating.

The rudder is at a long distance of the center of gravity, which is close to the cockpit, so it generate an important momentum, giving you the impression of a minimal inertia. But the inertia is big, and it is this which can explain the oscillation.

The other planes don't behave like that (or less than that) because their rudders is less effective. Maybe because the tail of the 109 is very long, the rudder generate a more important momentum.

Maybe exagerated, but not absurd.

[sturmkraehe]

It just seems that the damping coefficients around the yaw axis are quite low for this plane. May be linked to a centre of pressure for yaw movement too close to the centre of gravity. How far this is for this plane correct or not I cannot say. I also do not know how far the code uses damping coefficients at all. I know that in reality they are extremely difficult to calculate and they need to be taken with care. It is close to impossible to determine them in windtunnel tests. My guess is there is no available data at all for the damping coefficients for the planes we have. 

Edited June 1, 2014 by sturmkraehe

[Sternjaeger]

 

Didn't find the original post. Copy/past from Reflected answer above :

 

kiershar, on 29 May 2014 - 20:04, said:

 

I am not pilot myself, but I can do physics and the 109 behaviour seems to me to not be so absurd. Maybe exaggerated, but not absurd.

 

The rudder is very effective, and when you use it, the plane responds quikly and turn around the vertical axis, masking a wing of the airflow. So the wing on the side of the turn is dropping.

 

The moment of inertia around this axis is important, because the fuselage is long and heavy. The vertical surfaces tend to push back the plane in its original direction with a certain angular speed -> big kinetic moment. The plane is crossing the equilibrium position and is going to the other side with a consistant angular speed, and will do it again and again. The plane is oscilating.

 

The rudder is at a long distance of the center of gravity, which is close to the cockpit, so it generate an important momentum, giving you the impression of a minimal inertia. But the inertia is big, and it is this which can explain the oscillation.

 

The other planes don't behave like that (or less than that) because their rudders is less effective. Maybe because the tail of the 109 is very long, the rudder generate a more important momentum.

 

Maybe exagerated, but not absurd.

 

 

the point is that historically one of the complaints that Bf109 pilots had was about rudder authority, that's why from the late Bf109G-6 onwards the rudder was extended.

 

The "pendulum swing" effect shouldn't be so pronounced because all the control surfaces are balanced.

[ShamrockOneFive]

the point is that historically one of the complaints that Bf109 pilots had was about rudder authority, that's why from the late Bf109G-6 onwards the rudder was extended.

 

The "pendulum swing" effect shouldn't be so pronounced because all the control surfaces are balanced.

 

I ask out of ignorance but wasn't the issue more to do with the increasing torque from the engine requiring more vertical stabilizer? Similar to how the Spitfire's tail got larger and larger as the power increased from 1000hp to 1500hp to 2000hp.

Edited June 2, 2014 by ShamrockOneFive

[wastel]

It was done to compensate the more powerfull engines with their higher torque, especially to make the takeoff a bit easier.

I guess for normal and combat flight manouvers, the normal stab+rudder was enough.

 

but even as an "only glider pilot" i have to say that the movement abround the vertical axis feels wrong.

here Sternjägers RL experience is of course more worth than my "powerless" flight experience :-)

 

And when looking at mustangss videos, showing an behavior that only the 109 in game has,

there seems to be really something wrong within the 109 flight physics.

 

 

Edited June 2, 2014 by wastel

[Sternjaeger]

I ask out of ignorance but wasn't the issue more to do with the increasing torque from the engine requiring more vertical stabilizer? Similar to how the Spitfire's tail got larger and larger as the power increased from 1000hp to 1500hp to 2000hp.

 

yes, but there were a lot of instances where the small rudder proved inadequate, especially at low speeds on takeoff/landing.

 

Don't forget that the rudder was designed to cope with the early Jumo-engined versions and wasn't changed until after the introduction of the DB605.

 

Years ago I talked to a Regia Aeronautica pilot who was based in Sicily on an airfield shared with the JG53, they all testified a German taking off on scramble with a drop tank under the belly: the pilot gave power too fast, they could see from where they were standing the rudder being pushed to the max to counteract the torque, but the aircraft was aiming for the shelters. The pilot managed to take off, but his tank and prop struck the edge of one of those shelters, and the result was a dramatic fireball that extended for hundreds of meters. 

Edited June 2, 2014 by Sternjaeger

[SR-F_Winger]

yes, but there were a lot of instances where the small rudder proved inadequate, especially at low speeds on takeoff/landing.

 

Don't forget that the rudder was designed to cope with the early Jumo-engined versions and wasn't changed until after the introduction of the DB605.

 

Years ago I talked to a Regia Aeronautica pilot who was based in Sicily on an airfield shared with the JG53, they all testified a German taking off on scramble with a drop tank under the belly: the pilot gave power too fast, they could see from where they were standing the rudder being pushed to the max to counteract the torque, but the aircraft was aiming for the shelters. The pilot managed to take off, but his tank and prop struck the edge of one of those shelters, and the result was a dramatic fireball that extended for hundreds of meters. 

I am no expert. But shouldnt rudder size be kind of compensated by the distance from the COG? I mean the further back the rudder sits the less size it needs to produce simlilar sideward forces to a bigger rudder closer to COG. Simple matter of law of the lever and proportions over all.

I remember there was a thread somewhere where some interviewed WWII 109 pilot (or was it a current day restorated 109 pilot) in a video referred to the 109s exceptional rudderauthority and therefor increased dogfighter capabilities.

Edited June 2, 2014 by VSG1_Winger

[DD_bongodriver]

Skip Holm? he is the poster child of 109 fandom.

[SR-F_Winger]

Skip Holm? he is the poster child of 109 fandom.

I dont remember if it was him talking about it. But no matter if he is biased. My common sense still stands:) At least until people stop claiming quotes and actually deliver sources (that is if they actually really want to have things changed in sim). If i am not mistaken history shows 777 doesnt change anything until there is solid evidence - with good reason.

Edited June 2, 2014 by VSG1_Winger

[Sternjaeger]

I am no expert. But shouldnt rudder size be kind of compensated by the distance from the COG? I mean the further back the rudder sits the less size it needs to produce simlilar sideward forces to a bigger rudder closer to COG. Simple matter of law of the lever and proportions over all.

I remember there was a thread somewhere where some interviewed WWII 109 pilot (or was it a current day restorated 109 pilot) in a video referred to the 109s exceptional rudderauthority and therefor increased dogfighter capabilities.

 

we're talking about rudder authority here: the only way to counter the torque effectively is by deviating the airflow generated by the propeller, so you'll need an exponentially bigger rudder to ensure the response and efficacy of the rudder and its authority.

It's not that the rudder as it was wasn't enough, it just didn't give a complete and 100% effective control, so in situations with high torque and low airspeed (take off and landing for instance) you would  have the former prevailing over directional control.

I dont remember if it was him talking about it. But no matter if he is biased. My common sense still stands:) At least until people stop claiming quotes and actually deliver sources (that is if they actually really want to have things changed in sim). If i am not mistaken history shows 777 doesnt change anything until there is solid evidence - with good reason.

 

that's true, but curiously the Russian flight models are much more refined and faithful to the expected behaviour of the real aircraft, because physics are the same for all.

Edited June 2, 2014 by Sternjaeger

[SR-F_Winger]

I know what rudder authority is. I flew the Fokker DR1 in ROF really long:) And my simplistic explanation applies to that.

And btw. i am on your side when it comes to twitchiness of the 109. I hope they can somehow make the 109 less twitchy while maintaining rudderauthority.

Edited June 2, 2014 by VSG1_Winger

[DD_bongodriver]

I dont remember if it was him talking about it. But no matter if he is biased. My common sense still stands:) At least until people stop claiming quotes and actually deliver sources (that is if they actually really want to have things changed in sim). If i am not mistaken history shows 777 doesnt change anything until there is solid evidence - with good reason.

 

We have dive test documents from Mtt themselves who considered the rudder authority on the 109 'insufficient', in the same sentence they mention directional instability, therefore small innefective rudder not far back enough to give stability.

[Kurfurst]

We have dive test documents from Mtt themselves who considered the rudder authority on the 109 'insufficient', in the same sentence they mention directional instability, therefore small innefective rudder not far back enough to give stability.

 

Would you kindly post the relevant part of the report? TIA!

[SR-F_Winger]

We have dive test documents from Mtt themselves who considered the rudder authority on the 109 'insufficient', in the same sentence they mention directional instability, therefore small innefective rudder not far back enough to give stability.

So did you post your sources to the devs/here in the forums (or what Kurfürst said)? If so forget what i wrote about missing sources please:)

Edited June 2, 2014 by VSG1_Winger

[DD_bongodriver]

The source was made available in several threads in the history section, the threads inevitably got closed down once Kurfurst and Crump got a little upset so it will take some searching through the threads.

[Sternjaeger]

I know what rudder authority is. I flew the Fokker DR1 in ROF really long:) And my simplistic explanation applies to that.

And btw. i am on your side when it comes to twitchiness of the 109. I hope they can somehow make the 109 less twitchy while maintaining rudderauthority.

 

No offence, but that's where "simplistic" doesn't help: you can't compare the two, we're talking +1200hp with a three bladed propeller vs what, 150hp and a thin Axial fixed pitch prop? What you get with a Dr.I is pretty much complete authority, whilst full rudder applied to a Bf109 will not give you the "full response" you'd expect like on the Dr.I, because the propwash is much more powerful and the rudder doesn't offer enough surface to counter it effectively throughout the whole flight envelope.

 

Things got worse as engines became more powerful, so they introduced rudders with bigger surfaces to ensure an effective response when needed.

 

But mind you, none of this has to do with the pendulum effect we're getting at the moment, if anything the continuous waggling of the tail should be less pronounced, since there is no control surface flutter and the airflow would prevail.. it behaves like the response of an unbalanced rudder, but at least visually it doesn't behave like it.

Edited June 2, 2014 by Sternjaeger

[Kurfurst]

Please note that bongo was referring to the "Messerschmitt dive trial" that

 

a) does not make the statements bongo claimed,

b) does not test normal flight but flight behaviour above maximum dive speeds of the aircraft and at high Mach numbers,

c) is written in a langauge that bongo does not understand or speaks

 

Control oddities related to high Mach number and flutter were, of course, observed during the trial (as they were in all such trials in every country) which as noted was flown above the Vne and whichs goal was to find during the practical experimentation the terminal velocity of the modified 109F testbed, but it does not make any of the statements bongo is referencing to.

 

The Bf 109s directional stability was relatively  low, but none of the trials executed anywhere seems to refer to an excessive swing back and forth.

 

The example of 109F-2 tested in the U.K. was noted to have the following stability and control characteristics:

 

From:  http://kurfurst.org/Tactical_trials/109F2_UK/109F2_ES906_AFDU.html

 

Flying Characteristics

 

4.   The controls are well balanced and the aircraft is pleasant to fly, but is not so easy to take off as the Me.109E.   The elevator control is fairly heavy but the rudder control is light and is effective even at low speeds, the aircraft being very sensitive to over-correction on the rudder during take-off. The Me.109F is not as easy to land as the Spitfire, altough it is a little easier than the Me.109E, due to its slightly better forward view.   The speed of approach for landing is about 110 m.p.h., and the angle is rather steep, which necessitates a big change of attitude before the final touch down.   Altough the landing speed is high, the resultant run is short and brakes can be safely applied as soon as the aircraft is on the ground.

 

 

The example of 109G-6 tested in the U.S.A. was noted to have the following stability and control characteristics:

 

From: http://kurfurst.org/Tactical_trials/Bf109G-6_US_EB102/109G-6_US_EB102.html

 

d.    Handling and Control at Various Speeds.

 

               The aileron and rudder control is good. The aileron forces are light and the airplane gives the impression of having a very high rate of roll at cruising speeds. The forces increase at high speed becoming very heavy around 500 kph indicated. The elevator force is extremely high at the higher speeds and is one of the most objectionable features of the airplane. There does not seem to be sufficient backward elevator travel, even with the stick full back the control does not feel adequate.

 

e.    Trim and Stability.

 

The only trim provided is on the horizontal stabilizer which is effective and easily trimmed. Considerable rudder force is required at low speeds and high power to keep the ship trimmed. The ship is directionally and longitudinally stable and seems to have neutral stability."

 

 

So much for "insufficient rudder authority"...

Edited June 2, 2014 by VO101Kurfurst

[SR-F_Winger]

No offence, but that's where "simplistic" doesn't help: you can't compare the two, we're talking +1200hp with a three bladed propeller vs what, 150hp and a thin Axial fixed pitch prop? What you get with a Dr.I is pretty much complete authority, whilst full rudder applied to a Bf109 will not give you the "full response" you'd expect like on the Dr.I, because the propwash is much more powerful and the rudder doesn't offer enough surface to counter it effectively throughout the whole flight envelope.

 

Things got worse as engines became more powerful, so they introduced rudders with bigger surfaces to ensure an effective response when needed.

 

But mind you, none of this has to do with the pendulum effect we're getting at the moment, if anything the continuous waggling of the tail should be less pronounced, since there is no control surface flutter and the airflow would prevail.. it behaves like the response of an unbalanced rudder, but at least visually it doesn't behave like it.

No offense taken! I was refering to the DR1 only to explain why i know what rudder authority is:) Sure there is no way even the furthest backward placed small rudder can cause similar authority. Increased mass, inertness, propwash and whatever taken into account.

My point only is: You can not say just because the rudder of the 109 is comparably small, it cannot achieve sufficient authority.

 

EDIT: Great to have you here Kurfürst!

Edited June 2, 2014 by VSG1_Winger

[Sternjaeger]

fellas, why do you have to turn this thread into another penis length match? As the OP, I'm kindly asking you to take your crap somewhere else, thank you.

[SR-F_Winger]

Wow forums are so prone to misunderstandings. And here is the hard language and with it I take my leave off this thread:)

 

See you in the sim folks!

Edited June 2, 2014 by VSG1_Winger

[Gort]

Screw this talk of mission builders. What I want is to be assigned a target objective, accompanied by a terrible intel briefing. Then present me with a random set of variables like real life. Your job is to bomb a position, up to you how to do it. Let the sim change air to air and surface to air threat. Move the AA around, add small arms when you get too low, add opposition squadrons that are moved up from distant bases. Change it and have unexpected threats arrive, or vanish.

 

There should be a swarm of fighters fly overhead from time to time without seeing you. That really gives you an uncomfortable feeling as you press to your target. Where did they go? Will they hit us during our egress? $hit!

 

Believe it or not, the missions at Stalingrad during the siege probably don't need a dynamic campaign, just some minor movement and changes in threat locations.

[Sternjaeger]

Wow forums are so prone to misunderstandings. And here is the hard language and with it I take my leave off this thread:)

 

See you in the sim folks!

 

just for the sake of clarity, my post wasn't referred at you Winger.

[DD_bongodriver]

Please note:

 

The dive trial I referred to:

 

a. uses the exact statements I mentioned

b. rudder effectiveness is expected to improve with speed, despite this it was considered insufficient.

c. is conveniently translated into my native language.

d. the testing is conducted by Mtt themselves and not by enemy research establishments.

Edited June 2, 2014 by DD_bongodriver

[Kurfurst]

The Messerschmitt 109 is a subsonic aircraft... its control characteristics change (for the worse) at near-Mach numbers.

 

The issue in Il-2 BoS beta appears to be the insufficient directional stability at normal flight speeds.

 

Edited June 2, 2014 by VO101Kurfurst

[DD_bongodriver]

Through the speed range up to near mach numbers the increased dynamic pressure increases the effectiveness of control surfaces, they become crisper and more responsive, anyway it was my bad, it's actually the small fin of the 109 that is more responsible for it's directional instability and I was mistaken about the rudder, it was actually the elevators that Mtt considered 'insufficient'

[AX2]

Apologies for the oftopic :

I will only say one thing  about the Yak

Why the problem is always how good or bad it was BF 109? 

We have a one half UFO in the game and is called Yak 1, I worry about the future of BoS , if we start in That Way for VVS planes.

Really strive Yak , play with the engine ,  do aerobatics, deploy flaps,do crazy maneuvers, retract flap, Shake your Yak Hard and fast... Shake the Yak,  you will see , The Yak 1 would need a thread apart

 

Apologies again

Edited June 2, 2014 by Mustang

[Sokol1]

Would you kindly post the relevant part of the report? TIA!

 

Is not this, posted by Mustang in previous page?

 

http://www.4shared.com/office/WxaeCL0oce/Diving_Test_109F_WNr9228_ger_e.html

 

Sokol1

Edited June 2, 2014 by Sokol1

[AX2]

Sokol1 can you Help me  ? 

I was searching for RAF Spitfire test dive , Like my post for BF 109 Luftwaffe dive test.

I have no luck for now.     any advice ?

[AX2]

A BF 109 at climbing.  then  perform a heavy nose down at negative Gs,  without problems or Rolls

 

Minute 1 : 13 to 1 : 18

 

http://www.youtube.com/watch?v=i4JvotBOvnM#t=73

Edited June 5, 2014 by Mustang