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View Full Version : For Max Climb in 109 Do I Need To Keep Ball Centred?



ytareh
09-01-2009, 02:53 PM
As I have a twist rudder (dont try and convert me to pedals -been there, done that -hated 'em...)it feels really weird climbing with grip twisted to centre the ball but Ive started experimenting with this and it MAY be faster climbing -on the one hand having the ball centred all the time is kinda a golden rule but it seems that having the rudder dead straight is also needed for max speed...Anyway got an opinion?

ytareh
09-01-2009, 02:53 PM
As I have a twist rudder (dont try and convert me to pedals -been there, done that -hated 'em...)it feels really weird climbing with grip twisted to centre the ball but Ive started experimenting with this and it MAY be faster climbing -on the one hand having the ball centred all the time is kinda a golden rule but it seems that having the rudder dead straight is also needed for max speed...Anyway got an opinion?

megalopsuche
09-01-2009, 02:55 PM
There's no room for opinions here. It is a fact that your aircraft will climb faster when coordinated.

stalkervision
09-01-2009, 02:56 PM
I'm not going to even go there. http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif IMO the pedals IRL made it a whole lot easier to trim the aircraft.

Max climb I believe the plane shouldn't need a lot of trimming because it's below it's cruise speed still where it is in natural trim.

Pigeon_
09-01-2009, 03:11 PM
Not centering the ball results in your aircraft slipping through the air, rather than flying straight. This, in turn, will result in increased drag and disrupted airflow over the wings, thus giving you lower speed and less lift.

TS_Sancho
09-01-2009, 03:27 PM
A nice trick for holding coordinated flight in the BF109 series is to program a couple of keys to incremental rudder.

AndyJWest
09-01-2009, 04:04 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by TS_Sancho:
A nice trick for holding coordinated flight in the BF109 series is to program a couple of keys to incremental rudder. </div></BLOCKQUOTE>
I'm not quite sure what you mean here: could you expand on it a little...

WTE_Galway
09-01-2009, 05:12 PM
The ONLY advantage of uncoordinated flight is it can throw off the aim of someone trying to nail you with deflection shooting (probably why some noobs online get shot down more often as there flying improves for a short while).

All aircraft performance deteriorates when uncoordinated and to just add further annoyance your guns no longer hit where the gunsight crosshair points at.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by AndyJWest:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by TS_Sancho:
A nice trick for holding coordinated flight in the BF109 series is to program a couple of keys to incremental rudder. </div></BLOCKQUOTE>
I'm not quite sure what you mean here: could you expand on it a little... </div></BLOCKQUOTE>

go to keymapping and map the + and - rudder keys normally used by people flying with a keyboard and use them like trim

TS_Sancho
09-01-2009, 05:17 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by AndyJWest:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by TS_Sancho:
A nice trick for holding coordinated flight in the BF109 series is to program a couple of keys to incremental rudder. </div></BLOCKQUOTE>
I'm not quite sure what you mean here: could you expand on it a little... </div></BLOCKQUOTE>

The slipball centers at 400kph with the IL2 BF109 flight model, which has no pilot adjusted trim.

Below that it reguires left rudder input and above right due to P factor and all that good stuff.

Set a key command to incremental rudder in your control section and a click or two will allow you to maintain coordinated flight at your desired speed without constantly leaning on rudder pedal or twist grip.

BTW the ingame BF109's climb best at 260 kph indicated for those who didnt know.

AndyJWest
09-01-2009, 05:46 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
...program a couple of keys to incremental rudder.
</div></BLOCKQUOTE>


Ah, I'm with you now Sancho. I'd not realised that with a joystick/pedals connected, the keyboard Rudder Left and Rudder Right keys (',' and '.' by default) would still work, I now see that they do.

Though this seems to work, there are a couple of problems: (a) it is rather course, compared to normal trim adjustment, and (b) as soon as you apply any rudder with the twist grip, it goes back to 'neutral' - in fact with a rudder control with even slightly spiky output, you might find it tended to return to neutral all on its own. Still, it is worth knowing this, if only to save wear and tear on the wrists for those of us without pedals.

Does anybody else do this?

AndyJWest
09-01-2009, 06:09 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">...the ingame BF109's climb best at 260 kph indicated for those who didnt know. </div></BLOCKQUOTE>
Or thereabouts:
http://i958.photobucket.com/albums/ae65/ajv00987k/Bf109climbrates.jpg
Later 109s need to be a little faster, by the look of it. In practice, I'd think it would be better to go a little faster stlll, as the top of the curve is quite flat, and going faster (a) should cool the engine better, and (b) gives you a little more energy in hand should you get bounced on the way up. It is also easier to see where you are going in a more shallow climb.

I'm not entirely sure how the IL-2 Compare figures were arrived at, but they look plausible, and I know that below about 250 Km/h, the 109 tends to wallow about - usually an indication that you are on the 'wrong side' of the best-climb curve.

TS_Sancho
09-01-2009, 07:48 PM
rgr on the "thereabouts".

260kph is a convenient number to file away that applies across the spectrum of BF109 airframes.

Ty for the clarifacation.

na85
09-01-2009, 08:26 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by AndyJWest:

Does anybody else do this? </div></BLOCKQUOTE>

No, as I'm on an eastern binge right now and haven't flown the 109 in quite some time.

.... but I'm going to start using it. Even with pedals, keeping the 109 coordinated for long periods of time gets annoying.

akumadarkhadou
09-01-2009, 10:27 PM
Here is yet another n00b question: Why is it important to keep the ball centered? How often do you want to keep the ball centered and why? My ballpark is that keeping the ball center helps you get maximum thrust and maneuvarability out of the aircraft you are flying?

WTE_Galway
09-02-2009, 12:41 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by akumadarkhadou:
Here is yet another n00b question: Why is it important to keep the ball centered? How often do you want to keep the ball centered and why? My ballpark is that keeping the ball center helps you get maximum thrust and maneuvarability out of the aircraft you are flying? </div></BLOCKQUOTE>

It is also hugely important if you shoot using the gunsight rather than walking the tracer. If the ball is not centered the gunsight is out ... on a 109 at full throttle by a plane width or more.

McMosquito
09-02-2009, 01:47 AM
Is the same to use rudder or rudder trim, performance wise?

I can see no difference, since they both affect the airflow the same way. This just bothers me.

akumadarkhadou
09-02-2009, 02:01 AM
How does one go about keeping the ball centered?

na85
09-02-2009, 02:15 AM
"the ball" is that little thing on your instrument panel that rolls back and forth. One of the P-51D's has the ball immediately below the gunsight, in case you don't know what I'm referring to.

To keep it centered, the saying is "step on the ball"

That means: If the ball is to the left of center, you apply left rudder (i.e. make the nose of the aircraft go left).

If the ball is to the right, apply right rudder (make the nose yaw to the right).

Pigeon_
09-02-2009, 02:17 AM
Look at your inclinometer (turn indicator):

http://www.coryat.com/faa-pp-written/5.jpg

If the little ball is left from the center you need to apply left rudder. If the ball is right from the center, use right rudder. It's that simple.

The question of why to do this has already been answered in the previous posts.

Pinker15
09-02-2009, 03:16 AM
Best climb U will get at ball centered and closed radiators. Any turn or slide indicate more drag so affets lower climb rate.

danjama
09-02-2009, 04:20 AM
A nice trick i use in the 109 when climbing to keep the ball centred, is twist the stick until it is centred and steady and you have a steady climb position, then hit escape on the keyboard.

Then let go of the joystick and come out of the menu, and all the planes control surfaces should be frozen in the position you left them. Try it out. It takes practice to get right, but its nice not having to hold the joystck constantly.

Viper2005_
09-02-2009, 05:38 AM
Actually, the engineering answer is more complicated than simply keeping the ball in the middle.

This is because keeping the ball in the middle requires rudder deflection, which causes drag. Sideslip also causes drag.

However, the drag due to sideslip is going to vary roughly as the square of the sideslip angle. Obviously, there is going to be zero drag due to sideslip when the sideslip angle is zero.

Equally obviously, there is going to be a finite quantity of drag due to rudder deflection when the sideslip angle is zero.

Meanwhile, there is also a trigonometric thrust loss because the component of thrust acting in the direction of flight is going to vary roughly as the cosine of the angle between the thrust vector and the flight path vector (things are actually slightly more complicated due to P-factor).

The optimum climb is delivered by trading off these factors.

It may also be worth using some aileron deflection, depending upon the coupling between roll and yaw, and the roll stability of the aeroplane. This is because the trigonometric lift loss is proportional to the cosine of the bank angle, and is therefore small for small bank angles.

What generally comes out in the wash is that the optimum is always close to coordinated flight, but so long as there is some degree of asymmetry it is very unlikely that the rigorous optimum will be perfect coordination.

Some modern airliner flight control systems take this into account in the engine failure case, and will direct the pilot to fly an optimised combination of roll & sideslip for the conditions. This is worth a few percent.

It might be interesting to experiment with the devicelink autopilot to see if this sort of optimisation is practical and useful in IL2. It may be that a small amount of roll and yaw yield a small performance improvement over rigid coordination. The challenge is that the optimum degree of "uncoordination" is a function of the degree of asymmetry, and will therefore decrease as power decreases during the climb...

BTW, the other thing worth remembering is that the best climbing IAS generally decreases with increasing altitude as well.

This is at least partly because decreasing power decreases the load on the prop.

The best climb speed is that which maximises the specific excess thrust power.

The minimum power to fly speed is that which maximises (L/D)^(3/2). This is somewhat slower than the speed for L/Dmax. If the prop was perfect, (and 2nd order if the engine was insensitive to ram effect) then optimising the climb would simply be a case of setting the alpha required to give the maximum value of (L/D)^(3/2).

However, in reality the prop efficiency is a function of speed, and at zero TAS the prop efficiency is zero by definition.

This means that although the best climb is approximately achieved by flying at the EAS required to maximise airframe (L/D)^(3/2), you may well end up doing better by trading an increase in drag power from flying faster against a greater increase in thrust power brought about by increased prop efficiency from flying faster.

For various reasons, at low speeds with a constant speed prop you will tend to see higher prop efficiency as power is reduced, and for this reason, as power decreases at high altitude there may be a benefit from decreasing the climb speed to more closely approach the optimum suggested by simple theory.

With a supercharged engine, power actually increases slightly in the climb towards FTH, because the throttling losses decrease, and so a further small performance improvement might be available from slightly accelerating as FTH is approached, and then decelerating thereafter.

As with all things in aerospace, the deeper your examination of the subject, the more complicated the answers become.

The sort of complexity above is another of the many reasons for which UAVs have the potential to out perform equivalent manned aeroplanes. Human pilots don't have the computational resources necessary to fly a complex optimum profile, and so they generally have to make do with a simplified approximation, such as climbing at constant speed with the ball in the middle.

The difference between the simplified profile and the optimum profile may only be a few percent, but they all count, and they can make all the difference.

GIAP.Shura
09-02-2009, 06:14 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by McMosquito:
Is the same to use rudder or rudder trim, performance wise?

I can see no difference, since they both affect the airflow the same way. This just bothers me. </div></BLOCKQUOTE>

Theoretically, there is no difference but the Bf-109 does not have rudder trim.

akumadarkhadou
09-02-2009, 11:49 AM
So, keeping the ball centered is essentially important to the plane's gunsight working accurately? Wow, and I though I was doing everything possible to improve my aerial gunnery... You need not go into details about gunnery, but I am still perplexed by the ball in relation to gunnery. So, all-in-all, ball centered= gunsight accuracy?

F0_Dark_P
09-02-2009, 12:27 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by akumadarkhadou:
So, keeping the ball centered is essentially important to the plane's gunsight working accurately? Wow, and I though I was doing everything possible to improve my aerial gunnery... You need not go into details about gunnery, but I am still perplexed by the ball in relation to gunnery. So, all-in-all, ball centered= gunsight accuracy? </div></BLOCKQUOTE>

You are not just aiming with your guns you are aiming with the whole of your airplane, so of course you have to be coordinated http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

But flying with a little rudder trim is good
i read about a British pilot (don't remember who) but he always flew his spit with a bit of trim, so he would always slip and throw of the aim of the enemy's http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif

WTE_Galway
09-02-2009, 06:23 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by akumadarkhadou:
So, keeping the ball centered is essentially important to the plane's gunsight working accurately? Wow, and I though I was doing everything possible to improve my aerial gunnery... You need not go into details about gunnery, but I am still perplexed by the ball in relation to gunnery. So, all-in-all, ball centered= gunsight accuracy? </div></BLOCKQUOTE>

test it ... fly coordinated look at the tracer compared to the gunsight... stomp on the rudder fire again, observe the difference

akumadarkhadou
09-02-2009, 08:09 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by WTE_Galway:
test it ... fly coordinated look at the tracer compared to the gunsight... stomp on the rudder fire again, observe the difference </div></BLOCKQUOTE>

Okay, I have tested it, and wow what a difference it makes. Keeping the ball in the center IS important, but what do you do with a plane that has no rudder trim i.e. the bf-109?

WTE_Galway
09-02-2009, 08:43 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by akumadarkhadou:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by WTE_Galway:
test it ... fly coordinated look at the tracer compared to the gunsight... stomp on the rudder fire again, observe the difference </div></BLOCKQUOTE>

Okay, I have tested it, and wow what a difference it makes. Keeping the ball in the center IS important, but what do you do with a plane that has no rudder trim i.e. the bf-109? </div></BLOCKQUOTE>


Three possible solutions ...

Either:

- co-ordinate with rudder when lining up a shot

or

- get to know how much to adjust for slip at a given throttle and speed (eg 3/4 throttle shoot just out from left wing tip etc)

or

- ignore the gunsight altogether and aim with tracer

akumadarkhadou
09-02-2009, 10:24 PM
Wow... German pilots must have been something else in order to take down other planes having to shoot under such conditions.

Billy_DeLyon
09-02-2009, 11:56 PM
It becomes second nature pretty quick if you fly 109s a lot. You just learn to keep steady pressure on the rudder pedal, gradually changing the pressure as your speed changes, to keep the slipball centered. As you get used to the 109 you'll find that you don't even need to look at the ball much, you'll automatically change rudder input as your speed changes.

It's said, though, that many RL 109 pilots' left thigh was bigger than their right, due to the force required to sustain coordinated flight at higher speeds! Something else, indeed.

T_O_A_D
09-03-2009, 02:55 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by TS_Sancho:
A nice trick for holding coordinated flight in the BF109 series is to program a couple of keys to incremental rudder. </div></BLOCKQUOTE>

I'd like to just point out. It's a Good Idea and I use the Numpad for this, over and above my stick and rudder combo.

789 Elevator trim 8 being neutral
456 Aileron trim 5 being neutral
123 rudder trim 2 being neutral

But for this conversation the 109 only has Elevator trim.
It uses Fletchner tabs for aileron and rudder trims, and both are hand adjusted on the ground.
You can not do it in the air. So your forced to use your main rudder. Thus inducing the drag mentioned. Albeit it's better to do this than slip.

But these key assignments work the treat on a fully enabled aircraft like the P-51 and others.

Kettenhunde
09-03-2009, 07:34 PM
If you want maximum climb performance keep the aircraft in coordinated.

If you want shooting accuracy, keep the aircraft coordinated.

freakvollder
09-05-2009, 10:13 AM
Don't waste your time by looking always on the BALL when climbing! In a combat situation it is more important to look at the enemy plane. You can climb not that better by centring the ball (watch your speed!). When you use the rudder a lot (what you should do to fly the 109 more efficiently) then the ball is not centred all the time but the manoeuvring is more effective fore example you can improve the view out of your canopy.

Don't overestimate the BALL in combat situation.

That are just my opinion and reflect my combat experiences.