The 109... questions

[Winger]

Hey guys. What am i doing wrong? Everytime i seem to screw the engine for no obvious reason. Oil and watertemps are fine and i always try and keep her good below 2500 revs.
I somewhere read that pulling up the throttle too fast can damage the engine. Ist that correct? Could that be it?
Or am i missing any other settingg that must be handeled with complex engine management other than revs, oil and water temps and if the gear is up or down. What is the deal with the ATA pressure? Is there a way to control it? Whats the perfect value? Where is ATAs critical area beginning?
Would be cool if someone could give me something like a list of thigs to do and things not to do in order to get optimal performance out of the 109. I never seem to get her faster than 400 kph in a level flight. Isnt she supposed to make much more?

Thanks!

winger

[born2thrill]

Are you opening oil rads, i put them full open seems to fly fine?

[Winger]

Are you opening oil rads, i put them full open seems to fly fine?

Oil rad is open. Not full since i am used to handle radiator setting dependant on temperature. So with Oiltemp of 60 degree theres no need to fully open the oilradi right?

Winger

[II./JG1_Krupinski]

What about water radiator as well? Water temp needs to stay @ 80C up to 105C only in short burst.

My preferences are to have the oil temp about 50C, water slightly above 80C.

Also, what is your RPMs? If they are above 2500 RPM, then you will indeed blow the engine. Cruising should be set to 2300 RPM, and the throttle set to 1.2 ATA.

[whatnot]

How realistic is the Complex Engine Management on CloD? Can I expect same reactions on different settings as with the real thing? Could I take the radiator, pitch, manifold pressure etc settings from pilot's notes from a real thing and apply them to CloD?

I know one of us have lurking here has tried that by now ;-)

[Winger]

I found out that getting speed above 300 simply takes time. Adjusting pitch so that revs are around 2200 and then just wait a little. Well, its no sportscar:). I managed to get her to 450 at 2km today. AI spits werent able to flee. Not sure on how efficient they flew.

Winger

[Blackdog_kt]

I use the settings specified in the manual with CEM and temperature effects enabled. I can exceed the RPM limit briefly with no problems as long as i keep temps in the normal range.

Generally speaking, manifold pressure is a measure of the pressure within the engine manifold intake where the fuel and air get mixed, just before they are fed to the cylinders for ignition. At least this is how it's measured in engines using a carburetor, i'm not sure where it's measured in the 109's injection system, but the general idea is the same. It might sound funny, but what it does is show you how hard your engine sucks at any given time :-P

If the intake is full open it's sucking the maximum amount of air, you get higher manifold pressure values on the instruments and more air means more fuel/air mixture to burn which translates to more power. It's what your throttle lever does, controlling that gate/valve in the intake to restrict or allow airflow to the engine.

So, with the throttle at idle your MP gauge will actually read less than the outside air pressure because the engine is starved for air, but with the throttle at full it will show the exact outside pressure. If you have a supercharged engine like the fighters in CoD have, it will even show more than the ambient pressure because the supercharger compresses the air even further before feeding it to the engine.

Depending on the aircraft you fly, it's measured in different ways. German aircraft measure it in atmosphere/bar units and that's what your Ata gauge reads, 1 Ata is actually the air pressure at sea level on an average day.

Since the 109 is fitted with a supercharger, you can go higher than that to 1.3-1.4 Ata. As you climb higher, the air outside is thinner so it gives less pressure, but thanks to the supercharger you can have sea level performance of 1 Ata pressure at 3-4 km of altitude (approximately, don't remember at what altitude exactly it starts to drop off). Going even higher, even the supercharger can't keep up with how thin the air is so you will notice it dropping below 1 Ata at some point.

This is the fundamental difference between real aircraft (which CoD now models accurately) and how we used to do things in the previous IL2 sims: full power is not always full throttle. Power is a combination of throttle and RPM, even mixture if we want to go really complex on the matter.
In fact, there are WWII fighters where going full throttle while on the ground or at low altitude could destroy the engine in a couple of minutes, because full throttle at low altitude can exceed the engine's maximum rated power. They were built to generate a lot of "reserve pressure" to compensate during high altitude flight, but if that reserve was added to an already high-pressure starting point (when low, with a high ambient pressure) it could blow the engine to bits.

Full power is the amount of pressure the engine can tolerate at a certain RPM value that generates the maximum horsepower. For the 109 it's around 1.4 Ata (i think). When on the ground, you can easily achieve 1 Ata with the throttle pushed mid-way, when flying at 6km of altitude you will be hard pressed to achieve the same value with the throttle wide open due to the drop in the outside pressure: the engine can only work with what its given-->the air it sucks from outside the plane.

Also, if climbing/diving you can see the Ata value decrease/increase without even moving your throttle: it's the outside air changing in pressure that affects the amount of pressure in the engine induction system.
Finally, reducing prop pitch too much has the effect of transferring resistance from the blades to the engine and this increases the pressure. That's only a rough and by no means accurate description of the effect, just be wary that reducing RPMs too much while on high throttle settings might push your Ata over the limit.

So, with all that out of the way, let's see some usable values.

For climb and combat i usually set the throttle for 1.3-1.35 Ata, which is what the manual specifies. If i don't make any drastic altitude changes during the fight it tends to stay relatively steady, so i spend most of my time baby-sitting the RPMs.
This is quite hard to control in precision, so i just focus on maintaining the 2500 RPM redline limit. According to the manual, the actual never exceed RPM during dives is 3000 RPM so you have some wiggle room. I have used 2700 RPM on occasion, either by mistake or to get some extra "pull" from the prop during combat and the engine didn't die on me. It's doing fine as long as you don't leave it there but bring it back to 2500 RPM within 5-10 seconds.

I have not experimented with the oil cooler too much, but i can safely run combat power settings (1.3 Ata and 2300-2700 RPM) with the oil cooler about 3/4 open. Maybe it's possible to make do with closing it a bit and gaining some extra airspeed but i haven't tested it yet.

The one that's hard to get right in the 109 is the water cooler. Water seems to heat up and also cool down faster than oil, so power changes have a much more immediate effect. I might suddenly need to increase power and risk having it overheat, or i might chop throttle during the dive and have it cool down too much. As a matter of fact, i always give it 2-3 keypresses of the "close water rad" command before going in a protracted dive and increasing it afterwards.

This is made a bit harder by the way we get feedback from the control. While it's easy to judge the position of most controls by looking at the cockpit levers or the overlay panel, the water cooler cockpit control is a rotating crank whose position is hard to judge (it turns more than a full circle so you can't just look at it and know its position) and the info window with the engine controls doesn't display actual position either. It just displays if it's in motion: up when you are pressing the open key, down when you're pressing the close key and center when you are not messing with it.

Due to these reasons, for the most part i run with the water coolers almost all the way open during combat. In the 110's info window the water cooler is depicted similar to the other controls (the slider shows actual position) so it's easier to set precisely and gain some extra speed.

I'm sure that if they changed the info window display on the 109 to be like the 110 i could manage the water coolers better and maybe gain some extra airspeed. Currently, keeping the RPM at the right place (within limits but not too low to deliver useful power) is already taking up most of my attention so that i can't afford the guesswork involved with the water cooler's position and i just leave them fully open.

For example, when diving i reduce prop pitch a couple of clicks, increasing it again during the pull out, but both the blade angle (visible on the clock-like instrument) and the RPM still take some time to adjust, so you actually need to be thinking ahead and applying changes before the start of your maneuver.

I spent 15 minutes chasing an AI hurricane in a climbing scissors fight yesterday, gaining on him and then having me overtake me, until i realised that i was making a mistake with my prop management. As soon as i started paying more attention to maintaining as close to 2500 RPM as possible, i was able to easily close up on him and shoot him down.


Sorry for the marathon post, this sim has so much depth at high realism settings that describing a simple boom and zoom bounce takes 2-3 paragraphs to explain what controls to use, how and why :-P

[Winger]

Blackdog. Thanks a lot for the information. A real useful post. I will have to re read it a few times and i guess getting the optimal power out of this bird will take quite some time and practice. But i look forward to do so and become good in it one da:)

Winger

[xnomad]

@Blackdog_kt

Excellent write up.

Here's a tip:
The water radiator settings can be seen on the wing roots of the 109. There is a little rod/pin that shows the radiator settings. Lean out and look down and you'll see them. If the rod is all the way out the rads are fully open. If the rod is not visible the radiator is fully closed. If you zoom in on them you can see the settings labelled in fractions.

There should also be a degree indicator on the left wing showing the flaps position but it's not there. In the picture below it is on the right wing.
http://www.pbase.com/bertone61/image/79470175

[madrebel]

kurfurst has the original engine docs on his site. i'm not sure if th game is using the 601a0 or 601a1 so i'll link both.

A0 (http://www.kurfurst.org/Engine/DB60x/DB601_datasheets_A0.html)
A1 (http://www.kurfurst.org/Engine/DB60x/DB601_datasheets_A1.html)

fairly certain the game is using the A1. i'm not 100% positive on the manifold (aTa) setting but iirc is should be 1.3 for 30 minute power and 1.42 for 1 minute WEP.

[Blackdog_kt]

@ xnomad and madrebel: Excellent, thanks a lot, i will check out the documents now and the radiator indicator next time i fire up the sim.

[schnorchel]

CEM and temperature effect on @4km, set 85% pitch get 2550 RPM, RAD full open, throttle 100%( I can not find a WEP on 109E3 so far) water temp 100C, I can only get 400km/h IAS. means almost 500km/hTAS, I think it is too slow. something wrong I did?

[engarde]

As an aside, i have read that many P38's in Europe were lost on the bounce as they were difficult to quickly set up for combat trim.

Perhaps these posts were the very same difficulties discussed over evening muster back in the day?

[Winger]

@Blackdog_kt

Excellent write up.

Here's a tip:
The water radiator settings can be seen on the wing roots of the 109. There is a little rod/pin that shows the radiator settings. Lean out and look down and you'll see them. If the rod is all the way out the rads are fully open. If the rod is not visible the radiator is fully closed. If you zoom in on them you can see the settings labelled in fractions.

There should also be a degree indicator on the left wing showing the flaps position but it's not there. In the picture below it is on the right wing.
http://www.pbase.com/bertone61/image/79470175

Hey. How did you set up zoom if i may ask? Are you pressing a key and then moving the mouse? I find that pretty circumstantial and set 2 axes of my hotas to have they mouse Y-Axis and another one to toggle zoom mode. My problem with that is that i cannot seem to influence the speed in wich the zoom changes. And by default its pretty damn fast.
I would love to have the possibility to change zoom slowly and kind of "analog" by simply pressing and holding one button to zoom in and another to zoom out. Dont know if you guys know ROF. But they solved this pretty perfect. There is a setting with wich you can influence the inertia of the zoom. Is there something like that in CLOD too?

Winger

[adonys]

I've found out it's rather hard to exceed 400 IAS in Bf109E3, but sometimes you can do it.

Combat (full power settings - bold settings are your main goal):
- oil radiator almost closed 30% open (between 20-40% open, I'm modifying it all the time) - keep an eye on oil's temp all the time
- prop pitch anywhere around 90% (between 80-100%, I'm modifying it all the time, accordingly with oil rad modifications, and trying to keep the RPM in the desired area)
- throttle kept modified (accordingly with the above oil rad and prop pitch settings and trying to keep the RPM in the desired area)
- RPM around 2500 (between 2000 and 3000)
- speed over 400 IAS
- water rad fully open

Don't forget to lower/cut the the throttle in dives (and eventually ease your prop pitch too), and get it back once leveled.

Cruise (economy settings - bold settings are your main goal).
- water radiator fully opened
- oil radiator fully opened
- prop pitch 100% (between 90-100%)
- throttle around 45% (between 45-55%)
- RPM around 2000
- speed over 300 IAS
- manifold pressure as lower as you can manage it (to conserve fuel while keeping a reasonable speed)

[robtek]

Here is the howto for the 109E :
http://rapidshare.com/#!download|688dt|176645974|Bf109E_Handbuch.pdf|160 97

[Blackdog_kt]

I've found out it's rather hard to exceed 400 IAS in Bf109E3, but sometimes you can do it.

Combat (full power settings - bold settings are your main goal):
- oil radiator almost closed 30% open (between 20-40% open, I'm modifying it all the time) - keep an eye on oil's temp all the time
- prop pitch anywhere around 90% (between 80-100%, I'm modifying it all the time, accordingly with oil rad modifications, and trying to keep the RPM in the desired area)
- throttle kept modified (accordingly with the above oil rad and prop pitch settings and trying to keep the RPM in the desired area)
- RPM around 2500 (between 2000 and 3000)
- speed over 400 IAS
- water rad fully open

Don't forget to lower/cut the the throttle in dives (and eventually ease your prop pitch too), and get it back once leveled.

Cruise (economy settings - bold settings are your main goal).
- water radiator fully opened
- oil radiator fully opened
- prop pitch 100% (between 90-100%)
- throttle around 45% (between 45-55%)
- RPM around 2000
- speed over 300 IAS
- manifold pressure as lower as you can manage it (to conserve fuel while keeping a reasonable speed)


Excuse me for saying so, but i tend to do cruise a bit different, lower the throttle and then drop the RPM. Reducing the pitch has the effect of raising the manifold pressure again, so i re-adjust the throttle which again affects the RPM (throttle affects RPM only on the German aircraft and on the RAF aircraft that don't have a constant speed prop, aircraft with a CSP keep the RPM steady on their own) and so on...but after a couple of back and forths it settles into a steady situation.

However, i use lower RPM (in fact i use the settings stated in the manual) with 1.2 Ata, since i think that RPM has a bigger effect on fuel consumption. For example, the Hurricane has a "cruise mode lock" on the propeller once you pull it fully back and it uses 1800 RPM or so for extra fuel economy.

Using 1.2 Ata, 2300 RPM and bit of trim i can easily cruise at 380-400 km/h with the water rads full open and the oil rads about 70% open.

The reason i'm using mid-range values for MP and RPM instead of high RPM with low MP is that every single aircraft checklist i've seen (both for combat and civilian planes) tells the pilots to use lower RPM in cruise to conserve fuel.

MP also has an effect in fuel consumption as the more air getting sucked into the engine the more fuel the metering valves/injection system/carburetors drop into he mix.

The thing is that using lower RPM lets you get more speed from the same amount of MP, as long as we're talking about cruise in level flight. After all, the reason RPM drops is because the prop is in coarse pitch and getting a bigger bite out of the air, making it more efficient for straight and level flight.
It's like going to 6th gear on a car when driving on a highway and dropping your RPM to 2500 without changing the amount of throttle you use: you won't accelerate/decelerate fast if you change how much you press the gas pedal, but you are sure getting where you want to go fast and with lower fuel burn, as long as you don't need fast responses from the engine.

Going low Ata with RPM is like doing the same speed in that car but instead of using 6th gear and 2500 RPM you use 4th gear and 6500 RPM: it's going to burn much more fuel and it's not even sure you'll get the same speed in the end.

The way it works is very different, but the end results are very similar so that it's easy to think of prop pitch and RPM like gears in a car. For example, whenever the car goes uphill we down-shift to increase our RPM and the engine's responsiveness, whenever the aircraft climbs we can go to high RPM to do the same.
During slow driving we use low gears that give us high RPM and fast response at low speeds, during the landing circuit we use fine pitch and high RPM for the same reason. Just like lifting your foot from the gas pedal will slow your car down via the gears if you are in low gear, using high RPM with low MP in an aircraft will do something similar. In this case however the braking is not only a function of the gearbox absorbing part of the energy, but mostly the propeller acting as an airbrake.

If you are on fine pitch/high RPM and the engine is not making enough power to turn that prop then it's getting turned by the air and windmills while at fine pitch (ie, the prop is almost flat, face-on to the incoming airflow)-->extra drag.

So, by using that analogy you can think of many useful scenarios.
What do you do to speed up in the dive faster or just let it pick up speed more efficiently? The same thing you'd do to speed up when driving a car downhill, progressively switch to higher gears/lower RPM while pressing the gas pedal or just go high gear and let it roll on its own. In our aircraft, this means coming back on the RPM a bit.

What if you want to go slow in the dive? Well, it's similar to what you'd do to keep your car from speeding up too much when driving downhill, use a lower gear/higher RPM while coming off the gas pedal. So, just chop the throttle and go to high RPM and the prop windmilling effect will give you the drag you need.

I'm not an expert or a real pilot and i certainly don't want to play it smart on you, i'm just surprised that your method is so different and that makes me want to compare notes.
You know, like a couple of pilots talking about "how to get that extra bit of performance" between sorties. Cheers ;)

[Winger]

Excuse me for saying so, but i tend to do cruise a bit different, lower the throttle and then drop the RPM. Reducing the pitch has the effect of raising the manifold pressure again, so i re-adjust the throttle which again affects the RPM (throttle affects RPM only on the German aircraft and on the RAF aircraft that don't have a constant speed prop, aircraft with a CSP keep the RPM steady on their own) and so on...but after a couple of back and forths it settles into a steady situation.

However, i use lower RPM (in fact i use the settings stated in the manual) with 1.2 Ata, since i think that RPM has a bigger effect on fuel consumption. For example, the Hurricane has a "cruise mode lock" on the propeller once you pull it fully back and it uses 1800 RPM or so for extra fuel economy.

Using 1.2 Ata, 2300 RPM and bit of trim i can easily cruise at 380-400 km/h with the water rads full open and the oil rads about 70% open.

The reason i'm using mid-range values for MP and RPM instead of high RPM with low MP is that every single aircraft checklist i've seen (both for combat and civilian planes) tells the pilots to use lower RPM in cruise to conserve fuel.

MP also has an effect in fuel consumption as the more air getting sucked into the engine the more fuel the metering valves/injection system/carburetors drop into he mix.

The thing is that using lower RPM lets you get more speed from the same amount of MP, as long as we're talking about cruise in level flight. After all, the reason RPM drops is because the prop is in coarse pitch and getting a bigger bite out of the air, making it more efficient for straight and level flight.
It's like going to 6th gear on a car when driving on a highway and dropping your RPM to 2500 without changing the amount of throttle you use: you won't accelerate/decelerate fast if you change how much you press the gas pedal, but you are sure getting where you want to go fast and with lower fuel burn, as long as you don't need fast responses from the engine.

Going low Ata with RPM is like doing the same speed in that car but instead of using 6th gear and 2500 RPM you use 4th gear and 6500 RPM: it's going to burn much more fuel and it's not even sure you'll get the same speed in the end.

The way it works is very different, but the end results are very similar so that it's easy to think of prop pitch and RPM like gears in a car. For example, whenever the car goes uphill we down-shift to increase our RPM and the engine's responsiveness, whenever the aircraft climbs we can go to high RPM to do the same.
During slow driving we use low gears that give us high RPM and fast response at low speeds, during the landing circuit we use fine pitch and high RPM for the same reason. Just like lifting your foot from the gas pedal will slow your car down via the gears if you are in low gear, using high RPM with low MP in an aircraft will do something similar. In this case however the braking is not only a function of the gearbox absorbing part of the energy, but mostly the propeller acting as an airbrake.

If you are on fine pitch/high RPM and the engine is not making enough power to turn that prop then it's getting turned by the air and windmills while at fine pitch (ie, the prop is almost flat, face-on to the incoming airflow)-->extra drag.

So, by using that analogy you can think of many useful scenarios.
What do you do to speed up in the dive faster or just let it pick up speed more efficiently? The same thing you'd do to speed up when driving a car downhill, progressively switch to higher gears/lower RPM while pressing the gas pedal or just go high gear and let it roll on its own. In our aircraft, this means coming back on the RPM a bit.

What if you want to go slow in the dive? Well, it's similar to what you'd do to keep your car from speeding up too much when driving downhill, use a lower gear/higher RPM while coming off the gas pedal. So, just chop the throttle and go to high RPM and the prop windmilling effect will give you the drag you need.

I'm not an expert or a real pilot and i certainly don't want to play it smart on you, i'm just surprised that your method is so different and that makes me want to compare notes.
You know, like a couple of pilots talking about "how to get that extra bit of performance" between sorties. Cheers ;)

Excellent. What are you in RL? Teacher? NO - should consider changing your job. Thanks for the writeup!

Winger

[adonys]

Excuse me for saying so, but i tend to do cruise a bit different, lower the throttle and then drop the RPM. Reducing the pitch has the effect of raising the manifold pressure again, so i re-adjust the throttle which again affects the RPM (throttle affects RPM only on the German aircraft and on the RAF aircraft that don't have a constant speed prop, aircraft with a CSP keep the RPM steady on their own) and so on...but after a couple of back and forths it settles into a steady situation.

it's the same thing I said. I was writing from memory (haven't checked exactly in the game), yet I've said throttle back and low RPM (around 2000, but actually going down towards 1800), if the high prop pitch rises the RPM, then you'll lower it until you get around the needed RPM.

Which is the RPM you're using for cruising, isn't something between 1800-2000?

The two important causes for fuel consumption are throttle RPM and fuel pressure. I said throttle RPM, because RPM going higher because of the wind forcing a faster rotation of the propeller shouldn't accelerate your fuel consumption. using the same car analogy, if you let it loose downhill, faster rotation of wheels because of the gravity won't make you consume more fuel to acquire it.

That's what I believe, I'm also no pilot, just using logic and knowledge. So, don't worry, I don't have any problem arguing or being corrected (I'm not stupid enough to think I'm always right, I'm not God), on contrary, these kind of discussions improves the knowledge of all of us, and that's a good thing, isn't it?

[Geronimo989]

Ok a quite simple and maybe stupid question: Does more RPM always mean more power on the 109, with the risk of breaking the engine when exceeding the limit? Or do you get maximum power when staying in certain RPM range (2500) and you actually LOSE power when you exceeding it?

[meplay]

I use the settings specified in the manual with CEM and temperature effects enabled. I can exceed the RPM limit briefly with no problems as long as i keep temps in the normal range.

Generally speaking, manifold pressure is a measure of the pressure within the engine manifold intake where the fuel and air get mixed, just before they are fed to the cylinders for ignition. At least this is how it's measured in engines using a carburetor, i'm not sure where it's measured in the 109's injection system, but the general idea is the same. It might sound funny, but what it does is show you how hard your engine sucks at any given time :-P

If the intake is full open it's sucking the maximum amount of air, you get higher manifold pressure values on the instruments and more air means more fuel/air mixture to burn which translates to more power. It's what your throttle lever does, controlling that gate/valve in the intake to restrict or allow airflow to the engine.

So, with the throttle at idle your MP gauge will actually read less than the outside air pressure because the engine is starved for air, but with the throttle at full it will show the exact outside pressure. If you have a supercharged engine like the fighters in CoD have, it will even show more than the ambient pressure because the supercharger compresses the air even further before feeding it to the engine.

Depending on the aircraft you fly, it's measured in different ways. German aircraft measure it in atmosphere/bar units and that's what your Ata gauge reads, 1 Ata is actually the air pressure at sea level on an average day.

Since the 109 is fitted with a supercharger, you can go higher than that to 1.3-1.4 Ata. As you climb higher, the air outside is thinner so it gives less pressure, but thanks to the supercharger you can have sea level performance of 1 Ata pressure at 3-4 km of altitude (approximately, don't remember at what altitude exactly it starts to drop off). Going even higher, even the supercharger can't keep up with how thin the air is so you will notice it dropping below 1 Ata at some point.

This is the fundamental difference between real aircraft (which CoD now models accurately) and how we used to do things in the previous IL2 sims: full power is not always full throttle. Power is a combination of throttle and RPM, even mixture if we want to go really complex on the matter.
In fact, there are WWII fighters where going full throttle while on the ground or at low altitude could destroy the engine in a couple of minutes, because full throttle at low altitude can exceed the engine's maximum rated power. They were built to generate a lot of "reserve pressure" to compensate during high altitude flight, but if that reserve was added to an already high-pressure starting point (when low, with a high ambient pressure) it could blow the engine to bits.

Full power is the amount of pressure the engine can tolerate at a certain RPM value that generates the maximum horsepower. For the 109 it's around 1.4 Ata (i think). When on the ground, you can easily achieve 1 Ata with the throttle pushed mid-way, when flying at 6km of altitude you will be hard pressed to achieve the same value with the throttle wide open due to the drop in the outside pressure: the engine can only work with what its given-->the air it sucks from outside the plane.

Also, if climbing/diving you can see the Ata value decrease/increase without even moving your throttle: it's the outside air changing in pressure that affects the amount of pressure in the engine induction system.
Finally, reducing prop pitch too much has the effect of transferring resistance from the blades to the engine and this increases the pressure. That's only a rough and by no means accurate description of the effect, just be wary that reducing RPMs too much while on high throttle settings might push your Ata over the limit.

So, with all that out of the way, let's see some usable values.

For climb and combat i usually set the throttle for 1.3-1.35 Ata, which is what the manual specifies. If i don't make any drastic altitude changes during the fight it tends to stay relatively steady, so i spend most of my time baby-sitting the RPMs.
This is quite hard to control in precision, so i just focus on maintaining the 2500 RPM redline limit. According to the manual, the actual never exceed RPM during dives is 3000 RPM so you have some wiggle room. I have used 2700 RPM on occasion, either by mistake or to get some extra "pull" from the prop during combat and the engine didn't die on me. It's doing fine as long as you don't leave it there but bring it back to 2500 RPM within 5-10 seconds.

I have not experimented with the oil cooler too much, but i can safely run combat power settings (1.3 Ata and 2300-2700 RPM) with the oil cooler about 3/4 open. Maybe it's possible to make do with closing it a bit and gaining some extra airspeed but i haven't tested it yet.

The one that's hard to get right in the 109 is the water cooler. Water seems to heat up and also cool down faster than oil, so power changes have a much more immediate effect. I might suddenly need to increase power and risk having it overheat, or i might chop throttle during the dive and have it cool down too much. As a matter of fact, i always give it 2-3 keypresses of the "close water rad" command before going in a protracted dive and increasing it afterwards.

This is made a bit harder by the way we get feedback from the control. While it's easy to judge the position of most controls by looking at the cockpit levers or the overlay panel, the water cooler cockpit control is a rotating crank whose position is hard to judge (it turns more than a full circle so you can't just look at it and know its position) and the info window with the engine controls doesn't display actual position either. It just displays if it's in motion: up when you are pressing the open key, down when you're pressing the close key and center when you are not messing with it.

Due to these reasons, for the most part i run with the water coolers almost all the way open during combat. In the 110's info window the water cooler is depicted similar to the other controls (the slider shows actual position) so it's easier to set precisely and gain some extra speed.

I'm sure that if they changed the info window display on the 109 to be like the 110 i could manage the water coolers better and maybe gain some extra airspeed. Currently, keeping the RPM at the right place (within limits but not too low to deliver useful power) is already taking up most of my attention so that i can't afford the guesswork involved with the water cooler's position and i just leave them fully open.

For example, when diving i reduce prop pitch a couple of clicks, increasing it again during the pull out, but both the blade angle (visible on the clock-like instrument) and the RPM still take some time to adjust, so you actually need to be thinking ahead and applying changes before the start of your maneuver.

I spent 15 minutes chasing an AI hurricane in a climbing scissors fight yesterday, gaining on him and then having me overtake me, until i realised that i was making a mistake with my prop management. As soon as i started paying more attention to maintaining as close to 2500 RPM as possible, i was able to easily close up on him and shoot him down.


Sorry for the marathon post, this sim has so much depth at high realism settings that describing a simple boom and zoom bounce takes 2-3 paragraphs to explain what controls to use, how and why :-P

Nice Blackdog :), was gonna go bed, but ooh il give it another hour :P

S!

[JG53Frankyboy]

watch the wings, there you see little sticks that show you the watercooler setting...

[Blackdog_kt]

it's the same thing I said. I was writing from memory (haven't checked exactly in the game), yet I've said throttle back and low RPM (around 2000, but actually going down towards 1800), if the high prop pitch rises the RPM, then you'll lower it until you get around the needed RPM.

Which is the RPM you're using for cruising, isn't something between 1800-2000?

The two important causes for fuel consumption are throttle RPM and fuel pressure. I said throttle RPM, because RPM going higher because of the wind forcing a faster rotation of the propeller shouldn't accelerate your fuel consumption. using the same car analogy, if you let it loose downhill, faster rotation of wheels because of the gravity won't make you consume more fuel to acquire it.

That's what I believe, I'm also no pilot, just using logic and knowledge. So, don't worry, I don't have any problem arguing or being corrected (I'm not stupid enough to think I'm always right, I'm not God), on contrary, these kind of discussions improves the knowledge of all of us, and that's a good thing, isn't it?

That's a good point you're raising there, if the engine "rolling downhill" consumes as much fuel as when it's working normally at the same RPM, to which i don't know the answer :grin:

In cruise i use the values stated in the PDF manual for CoD (1.2 Ata and approximately 2300RPM) and this easily gets me 390km/h IAS at low altitudes (2km or so).

There are also different kinds of cruise and we don't know which one the manual gives. Endurance cruise gives the most amount of flight time per liter of fuel.
Economy cruise is different and gives the biggest amount of distance traveled per liter of fuel.

Assuming i'm flying a cessna, let's say it has an economy cruise of 25 inches Hg manifold pressure and 2500 RPM and an endurance cruise of 20 in Hg and 2200 RPM:
If i use 25"/2500 RPM, my fuel will last a shorter amount of time but in that time i will have traveled a bigger distance.
If i use 20"/2200 RPM, my fuel will last longer but the total distance travelled will be less.

Applying this to the 109, i suppose the values states in the manual give the best range and not the best endurance/loiter time. This is a pure guess on my part, i'm just guessing that a sleek fighter will have a relatively high economy cruise speed and since i'm getting almost 400km/h it seems reasonable.

If we wanted to maximize time over London we would combine both, economy cruise to the target area, endurance cruise while patrolling and economy cruise back to base ;)

[adonys]

The cruise I've posted up in there was done at lower RPMs than the one in manual/yours (1800-2000 compared with 2300), and it is exactly for the lowest consumption of fuel/distance covered, therefore should be an economy cruise, not a fast (as I believe the one from manual to be, at 2300 RPM you're almost in the full power 2500 RPM area) or an endurance cruise (maximize the time staying in the air).

PS: yet, using the manual 2300 RPM for cruising.. isn't as being a lower RPM compared with my 2000(1800) one, as you said when we've started this discussion.. as it is actually a higher RPM, isn't it? :P

[Blackdog_kt]

Of course. I just went by the assumption that the manual states maximum range cruise. Maybe it's fast cruise and yours is more economical, i will probably try out your settings during the weekend ;)

[Hellbender]

Question: So far the Fuel mixture in the 109 could be set by me only @ 0 % or 100%. At high altitude, I see smoke coming out of the Exhaust which vanishs by using Mixture 0% which is giving me almost no engine power.
In british planes I can set up the fuel mixture from 0-100% , but i only got 2 extremes on the 109.

[JG52Uther]

I think mixture in the 109 is bugged at higher altitudes.

[robtek]

afaik there is NO mixture adjustment for the 109!
Always "auto-rich"

[adonys]

yeah, the mixture of 109 is auto, you shouldn't fumble with it.

[JG52Uther]

When I get the time I will take off from France and fly to London at cruise settings,to see how much fuel is left.
I think in real life they had 10 minutes or so combat time over London,so it must have been pretty hair raising trying to get back while avoiding enemy fighters. I already flew one mission out in the channel,got a fuel leak and only just made it back to base with empty tanks and the fuel light on! That was bad enough,and no one was shooting at me!

[adonys]

actually I remember that they had even less than 10, that being only 5 minutes of full power combat time above London.

it was the main reason Luftwaffe haven't completely obliterated britain fighters during BoB because someone decided to start it before having the fuel tank ready for the 109s (and the fact that all pilots bailing out were recovered and flying again the next day for britons, while was lost as PoW for germans).

[Al Schlageter]

When I get the time I will take off from France and fly to London at cruise settings,to see how much fuel is left.
I think in real life they had 10 minutes or so combat time over London,so it must have been pretty hair raising trying to get back while avoiding enemy fighters. I already flew one mission out in the channel,got a fuel leak and only just made it back to base with empty tanks and the fuel light on! That was bad enough,and no one was shooting at me!

Some data for the E-1/E-3

SL
Max continuous: 2200rpm, 254mph - 1.05hr, 267mi
Max economy: 1300rpm, 164mph - 2.02hr, 404mi

16,494 ft
Max continuous: 2400rpm, 323mph - 0.55hr, 286mi
Max economy: 1300rpm, 217mph - 1.50hr, 413mi

[II./JG1_Krupinski]

Ok a quite simple and maybe stupid question: Does more RPM always mean more power on the 109, with the risk of breaking the engine when exceeding the limit? Or do you get maximum power when staying in certain RPM range (2500) and you actually LOSE power when you exceeding it?

Absolutely not... However, power is dependent upon RPM. That is power is a "rate" of work being done.

Use the Prop Pitch control to regulate the engine load by maintaining a certain RPM. At a high pitch, it's harder for the engine to swing it than at a lower pitch.

All internal combustion engines produce power on what's called a power curve, named because the relationship between torque output and RPM is not linear - it's a curve. Hard to describe but imagine an engine running at idle may produce an increasing amount of torque at an increase of RPM (with a constant load) up to a peak.

Then any additional RPM beyond that peak will start reducing the torque output, even though RPM's are increasing. (Side Note: In internal combustion engines, the power and torque numbers are equal at 5252 RPM)

A dynamometer, is used to measure the power parameters of an engine. The dynamometer operator will increase the throttle from idle to max throttle and measure the RPM and torque output.

Using a variable pitch prop [bf109] or fixed pitch prop [tiger moth], the propeller can represent the constant load (assuming you don't change the variable pitch) exerted on the engine, and taking the throttle from idle to max throttle will exercise the engine across it's power curve.

If the propeller is a constant speed propeller (spit) then the propeller will adjust its pitch (adjust its load) automatically to maintain a certain load. Since the engine produces power on a power curve, you can stick the RPM to the peak level and then worry about one less thing. As you increase throttle, the engine RPM will increase until there is enough power to swing that prop at the given setting. A constant speed prop makes it easy to keep the engine at the best RPM for a given situation, such as MAX performance, or MAX economy.

A variable pitch propeller the pilot must adjust the propeller pitch to do the same thing, as an increase in throttle will increase the RPM of the engine, unless the pilot increases the load on the engine.

A fixed pitch prop, the pilot must adjust the RPM's with the throttle.

Usually, aircraft manuals aren't published with detailed power curves, but what they do have is settings for varying scenarios. The CoD manuals have some values published, but I've seen more detailed tables in other game manuals (such as the shockwave A2A Bf109 manual - which you can view online)

Here is a nice web page that discusses power and torque.

http://www.epi-eng.com/piston_engine_technology/power_and_torque.htm