Get the most out of the bf109

[41Sqn_Stormcrow]

I constantly have the problem that as soon as the bf109 gets a bit slow I cannot get her accelerate somehow in lvl flight (ok dive will do but that's not the only way to accelerate her). It seems as if she only bled speed and stays there.

I am also confused about the engine sound. It gets low frequency when I get slower but so much that I am always afraid that the engine stops at any moment. This is most sever in a steep climb. Here also the lack of performance is really evident.

I have been overtaken by spits with lowered flaps.

Also it seems that the 109 cannot turn at all. I know that it won't turn like a spit but as far as I know the discrepancy in turn ability between the spit and early 109 wasn't THAT huge.

So could some of your 109 experts give me some advice? I play full CEM.

[41Sqn_Stormcrow]

If that darn proppitch mechanism wasn't so darn slow ... :mad:

Is there a comparatively ideal rpm? I drive her around 2300 in order to not overrev in a dive considering the intertness of the pp mecha.

What about the oil and water temps?

[Blackdog_kt]

I'm going to go ahead and agree with what Cheesehawk said.

Especially the gear and car analogy is the one i use too whenever explaining CEM to someone :-P

In the sense, if you want to cruise at high speed keep it around 2000-22000 RPM.

Lowering the RPM confuses a lot of people because they think that they somehow lower their available engine power. What really happens is that the RPM lowers because the prop blade angle of attack increases: more resistance but also more pull.

Long story short, you will need to fiddle with the pitch control all day long. Don't expect to set it around 2300 as an all-around happy medium, leave it there and attain top performance.

Once again, think of gears in a car. Lower gears are useful for braking by loading the transmission system if you take your foot off the gas pedal, for getting a sharper, more lively response from the engine, going uphill or going downhill at slower speeds. What is the hallmark of a lower car gear? Higher RPM for the same speed. That's your mnemonic rule right there, whatever you want to do something that would have you down-shifting in a car, use higher RPM in the aircraft ;)

In a similar fashion, higher gears give you less actual "pull" in tricky situations and a slower engine response but they are great for attaining higher speeds and still be great for fuel economy. Again, higher gears means lower RPM for a given throttle setting and speed so that's your cue...whenever you want to do something that would have you up-shifting in a car, lower your RPM in the aircraft.

As for why the prop-pitch mechanism is slow, maybe it's partially dependent on the amount of airflow, the amount of throttle used and the airspeed. I have found that prop pitch changes are faster if i put some load on the engine or i'm going faster. Another way to speed it up a bit is to deliberately overshoot your intended setting in order to "kick-start" it so to speak, then bring it back where you want it.

Alternatively, fly a lot of free flights and get used to the sound of the engine. This way you can tune it by ear while looking outside the cockpit, instead of having to bury your head in the panel and check up on things in the middle of a dogfight.

I didn't expect it, but i actually find the little clock displays that indicate prop pitch very useful. They are at the upper part of the panel in both the 109 and 110 and are easy to keep in view. Between getting used to the engine sounds and noting down what my prop pitch settings are during certain scenarios, i can now fly without looking at the tachometer all the time.

This is also helpful to "change gears" and ties in with the way to use the entire system. These pitch changes are manually commanded, so it's like having a myriad of fixed pitch propellers. Well, every fixed pitch prop will maintain a certain RPM only under specific airspeed and throttle conditions. I hope i'm making sense here, i don't know how else to explain it in a simpler manner :-P

So, back on the topic of "shifting gears" in our plane, you have to take into account the aforementioned delay and plan a bit ahead.
For example, you just made a diving pass on some bombers and are about to pull up into an immelman in order to set up your next pass. Don't wait until you start pointing the nose up and the RPM drops, advance the pitch as the nose is still coming around to take advantage of the fact that you will get extra RPM as you are still diving and this will also help turn the blades to their new angle.

All in all, it's just like shifting gears but with a slight built-in delay. And in that sense, going flat out on full RPM will certainly not give you top speed.
I use 2500RPM when i want to climb or to accelerate, then i drop it back to 2100-2200 or so for level flight and dives.

This might be a bit confusing initially but due to the way Fw-190As were in the stock IL2 i got used to flying with manual pitch a long time ago (it performed better than with the auto system).

To sum up:
a) Remember that your RPM power band is from 2000 to 2500 RPM

b) Use the low part of the power band for top speed, cruise and accelerating in dives and accelerating in level flight when your airspeed is considered high (ie, sufficiently above cruise and closer to max).
It's like going from 5th gear to 6th, it will slowly give you that extra 30km/h in your car, if you go from 5th to 4th however you won't be able to get that top speed since even though 4th accelerates better overall the top speed range is out of its capability

c) Use the high part of the power band for top acceleration, especially from a slow starting speed, and fast engine response to throttle changes. This goes for throttle increase and decrease alike, which is why fine pitch is used in take-off/landing and for keeping formation. There's a reason why wingmen usually burn more fuel than the leader, they run somewhat higher RPM ;)

d) When you know you will change attitude and/or airspeed due to maneuvers, anticipate the needed changes in pitch and start them a bit earlier. If you see a hill or a truck you want to overtake ahead on the road and you know you are going too slow for your 5th to get you through it, you downshift to 4th in preparation for it. If you know you'll zoom back up after a diving attack, start increasing your RPM just as you stop pressing the fire button.
You might temporarily over-rev a bit but it's not sufficient to kill or even damage the engine. My only worry in such a case is that i might actually be lowering my airspeed prematurely by going to a "lower gear", the engine can take brief bursts of 2600-2700 RPM just fine. The key word here is brief, i routinely overshoot into the 2600 RPM range when pulling out from dives but it only lasts a few seconds (probably less than 5).

Hope it helps somewhat ;)

[bando]

Great explanation guys, thanks

[Geronimo989]

Thank you Blackdog for taking your time to explain this so well.
I have a couple of questions:
If you wanna achieve highest performance out of your 109 (not worrying about fuel or engine lifespan etc) Do you keep the full throttle and adjust the RPM with your pitch?
What is the maximum IAS you can get out of 109 in level flight at 1500m? I cant get over about 460 km/h (full throttle, about 2100 RPM) even though I was sure that in IL-2 I could get 500+ out of it...

[zwiebacksaege]

be sure that the E3 won't reach 500 km/h IAS. Not here and not in IL2.
460 is a nice value and possibly very close to the real machine

[Positronic]

good info, will put this into practice

[41Sqn_Stormcrow]

Thank you SO much, Blackdog. That is the best explanation I have read on this thing.

One thing still bugs me though but it is likely my fault:

I go quick mission one of the last ones and jump into a 109 where theres a lot of blemheims and spits around

I fly a long time (20mins or so).

I end up slow on deck. Ok

Now it takes an eternity to accelerate from 250 kmh to something higher.

Also even though I have full throttle (no WEP tho) and full prop pitch, the pp doesnt go further than 22000 or 23000 ...

[Blackdog_kt]

Thank you Blackdog for taking your time to explain this so well.
I have a couple of questions:
If you wanna achieve highest performance out of your 109 (not worrying about fuel or engine lifespan etc) Do you keep the full throttle and adjust the RPM with your pitch?
What is the maximum IAS you can get out of 109 in level flight at 1500m? I cant get over about 460 km/h (full throttle, about 2100 RPM) even though I was sure that in IL-2 I could get 500+ out of it...

Highest performance would probably be the highest manifold pressure you can run, with the lowest RPM within the useful power-band you can run at that manifold pressure without causing detonation (engine knock/pinging).

The tricky part with the RPM is that
a) going below the power band is not useful and
b) even when within the acceptable power band, there are limits to how low you can run the RPM at higher manifold pressure before detonation occurs.


Thank you SO much, Blackdog. That is the best explanation I have read on this thing.

One thing still bugs me though but it is likely my fault:

I go quick mission one of the last ones and jump into a 109 where theres a lot of blemheims and spits around

I fly a long time (20mins or so).

I end up slow on deck. Ok

Now it takes an eternity to accelerate from 250 kmh to something higher.

Also even though I have full throttle (no WEP tho) and full prop pitch, the pp doesnt go further than 22000 or 23000 ...


To be honest, this is the first i've heard of this. I was tinkering with bombers the last couple of days and the 110 before that, so i can't really remember if i've experienced a similar effect because it's been a while since i last sat in a 109.

As you can see i'm not an expert by any means, i've just read up a lot of stuff and practiced some of it in varying levels of realism when flying 3rd party add-ons for microsoft flight simulator X on a friend's PC.

Some of what i say might be inaccurate and i bet most of it is very simplified (if you want detailed, scientific explanations, look for Viper2000's posts) in the interest of learning enough to get the job done in the game without having to get an engineer's degree :-P

I just go by some widely accepted norms and test them in-game to see what happens, then describe the process with a real-life analogy that's easier to understand for those of us who are not real-life pilots or aeronautical engineers. Apart from that, there are others on this board that can provide better and more in-depth explanation and i'm in turn learning from them ;)

[Cap'n Crunch]

Don't have the game yet, but as far as your water rads, most will regulate the flow of water both ways. If it's cooling to effectively, a thermostat on the rad exit flow will close stopping the cooler water from flowing to cold back into the engine block. Most are familiar with the hot thermostat controlling flow to the rads, the autos have these, it's all they need. They don't operate in such extreme temperature bands with rapid changes.

Your oil system should be modeled similar, two control points. In real life, oil rads are often locked full opened a little prior to descents, if your going from cooler altitudes to extreme heat at low levels. It can buy you several extra minutes of ground engine run time dropping oil temps a few degrees and cold soaking the rads, handy for a quick combat turn around or an engine running offload.

Might be a better idea to open the rads full in a dive and slap them shut in the zoom. If your taking long dives and max effort zooming for it might pay off.

[Blackdog_kt]

Hmm, that's actually an interesting point. I'll have to remember to test it next time i fire up the sim, thanks for the heads up ;)

[kubanskiloewe]

imho unfortunately it´s not so complicated programmed as we real sim freaks wish it to be.

I can reach top speed f.e. in a 110 with cooler full open ar near closed and rpm´s from 1800 to 2300 or so.
dont think it´s much different in the 109 or others.
I suppose they give their cornerdata´s from aircrafts hardcoded ....and put the Rest as eye candy or some clickable features which make the player think it will influence something as it should be in real.
wep in the 109 is unlimited...when it´s gone just press the wep button

your head is able to turn 360° around in a fastened seatbelts ? no not really....here where obviously things made for Gamer´s....not for sim freaks....digital instruments in historical planes ?


in that respect i´m very disappointed from that what they programmed in 5years and with IL2 in the background.

far away from a sim in my view....

[KDN]

These were very helpfull posts.
Thank you Blackdog_kt and Cheesehawk

[WWWringer]

Blackdog_kt has made an excellent post.

I haven't bought CoD yet so one quick question before I get carried away in the discussion - are the propellors on the 109 (and all the other aircraft for that matter) controlled by Constant Speed Units OR are they just variable pitch propellors?

The difference being, after takeoff you have reduced your throttle setting and RPM to the recommended settings and accelerated to the recommended climb speed:

With a Constant Speed Propellor - if you vary your throttle setting up or down and/or change your attitude by pitching up or down (within reasonable speed and power settings) the engine will maintain the RPM you have set.

With a Variable Speed Propellor - if you do the above - the RPM will either increase or decrease from what you have set at the change of power and/or the change of speed.

(the Variable Speed Propellor requires a lot more work/attention from the pilot than the Constant Speed Propellor btw)

Next - because I haven't bought the game yet - I do not know how accurate the Simulation is but I think I can speak in general terms and offer some insight (I hope).

To determine how much Power (measured in Horsepower or NewtonMeters etc) the engine can develop you have to know the RPM and the throttle setting - the throttle setting on the '109 and most WWII aircraft is a measure of the Intake Manifold Pressure and on the '109 is measured in Atm - Atmospheres, I believe. (On the USA aircraft it is measured in Inches of Mercury).
On a `normally aspirated engine' - No Supercharger/Turbocharger - the maximum manifold pressure you could get - at ground level would be local atmospheric pressure - about 1 Atm or 30 Inches.
But most engines we will see in CoD are supercharged. (not the Tiger Moth :) ) Therefore we can get throttle settings (power settings - manifold pressures) of 1.5 Atm or 45 Inches of Hg etc.

Engine Manufacturers set limits on their engines - for reliability and engine life. These Limits are specified in maximum RPM and maximum Manifold Pressure. As well, for HIGH power settings, like Takeoff Power, there may be a time limit.
RPM limits are set so the engine stresses do not cause the engine to `fly apart' and Manifold pressures limits are observed so that the HEAT from combustion does not heat the engine to the point that the metal of the combustion chambers and pistons are weakened by the high temperatures to the point of failure.

On some engines there may be another HIGH power setting that has no time limit - less than Takeoff Power - and in North American Engines called METO - Maximum Except Take Off.

On Take Off different aircraft with different engines have different procedures for setting Takeoff Power.
Usually the Prop control is set to Maximum RPM or Full Fine.
The throttle is carefully brought up to the maximum Manifold Pressure specified (OR another controller automatically limits the Manifold Pressure to the maximum so all the pilot has to do is `firewall' the throttle - set it to `wide open')

The propellor and its controls are adjusted/set by the manufacturer and mechanics so that on Takeoff the engine will achieve - but not exceed - its maximum rated RPM. This RPM is usually governed so that the pilot can concentrate on the takeoff and not have to adjust the engine RPM down in the middle of the takeoff roll as his speed increases.

So we have taken off and reduced throttle settings (manifold pressures) and RPM to suitable values for the phase of flight.
Lets say we are cruising along at typical long range cruise values. Relatively low RPM has been set. refer to Blackdog_kt's excellent post.

Up ahead we spot co-altitude bogeys that are probably hostile so we want to increase our speed and energy state ( and climb). So to accelerate and/or climb we need MORE POWER. How do we get more power? By burning MORE fuel-air mixture. So we push the throttle up to the maximum value allowed! (on a constant speed prop the propellor will coarsen to maintain the set RPM - on a variable pitch prop the RPM will increase)
And we start to accelerate slowly/climb slowly. Not good enough! We need more power. How do we burn more fuel-air mixture? How do we increase the number of power strokes in the engine per minute when we are already at the Maximum Manifold Pressure? We INCREASE the RPM.

So, to accelerate from a steady speed we need more power (more force to appy to the mass to get the acceleration). We get that power by realising that power output is controlled by how much fuel we are burning and that is a function of RPM and Throttle setting (manifold pressure). Therefore we set - in this case - the maximum power setting allowed for this phase of flight - RPM and Manifold Pressure - maybe even going to the point of War Emergency Power.

When we don't need full power and want to conserve our limited fuel supply we choose a power setting with an efficient propellor setting - RPM - to get the best speed at that power (throttle setting).

Hope this adds to the discussion.

[KDN]

the Bf 109E4 and E4B have a variable propeller pitch. It is actually animated on the prop too.

[TUSA/TX-Gunslinger]

I have great luck running my 109E3 pitch at the 11:30 position. Even where the manual recommends 12:00 (at takeoff).

If I'm cruising around trying to save gas - maybe I'll take it down to 11:15 to 11:00.

If I'm diving, I'll cut it down in the 10's but since many dives result in a corresponding climb - I find the timing of the prop pitch changes throughout the normal "down" and "up" cycle take the longest to perfect.

S!

Gunny

[Flanker]

Can you control Bf-109 mixture and supercharger?

[Blackdog_kt]

Both mixture and supercharger are automatic in the 109.

[WWWringer]

Here's a nice video discussing the differences between:

1. A fixed pitch propellor

2. A variable pitch propellor

3. A constant speed propellor

It's for a different airplane and sim but the theory discussion is excellent.

http://www.youtube.com/watch?v=psYL7thQj6M

[Danelov]

Good video and well done. I like this game Battle of Britain II, a very good alternative.