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DCS Fw 190 D-9 Flight Manual


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  • ED Team
The mixture is leaning out, it should be outputting less power.

 

.7= (10.4/1)/14.9

.7= (20.8/2)/14.9

.8 = (10.4/.087)/14.9

.8= (20.8/1.74)/14.9

 

You're taking, roughly, 13 % of the fuel out from the mix; With every decline of .1 Alpha. You should see a drop in power. There is a lot less gas in the cylinders, combustion will be weaker. Unless you're starting out overly rich, than leaning would actually increase power.

 

Or does your model derive power out based on the difference of Alpha from 14.9?

 

Stoichiometry, 14.9, fuel air mixture, isn't the point of peak power in the fuel air mixture. It's just the point where all of the air input with the gas is also consumed. Peak power typically occurs somewhat richer than stoichiometry, down in the 12's (12.5 is typically assumed as best power mixture). While peak efficiency tends to be closer to stoichiometry but in the 15's.

 

Mixture controls and a throttle that controls airflow are useful to a piston engine pilot because they allow one to control the power band. So that they are always maximizing the VE of their craft.

 

A throttle which controls fuel flow is more appropriate for a jet, because the dynamics of the engine fuel flow has a very direct relation with power output.

 

"Alpha = (Air mass flow/Fuel mass flow)/14.9" This is an equation to calculate the difference between current mix and stoichiometry. It's not a good equation to derive power out put of a piston engine from.

Yes, it's not. The basic is the actual air mass flow, but alpha affects to the slight power changing.

By the way, comparing power peak at alpha=0.85 and power deviation within alphaMax/alphaMin~2 , the power deviations will be less than 10%

 

As you're not taking into account the varying power output achieved by mixture settings and what's realistically achievable by the engine and the induction system. If you keep fuel flow constant in the equation, then rises in mass flow reach such high levels, that one is not operating in a realistic band of manifold pressures. Again, a 13 percent increase in mass airflow is need to keep the power constant. If the volume of cylinders stays constant, at some point your either likely to exceed the engine's capacity to sustain those MP, or be at such a place where the equipment need to compress the air to those level, would no longer be efficient. IE running a 4 horsepower supercharger to gain 2 horsepower.

 

.7= (10.4/1)/14.9

.8= (11.92/1)/14.9

 

Further more, we can calculate the mass of the air based on the fuel flow. At a fuel flow of 1055lbs per hour (from the Jumo) assuming the same mixture here of 14.9

Air flow = 14.9 * fuel flow

10,972= 14.9 * 1055 (both sides in Lbs per Hour)

 

You can not use this equation because alpha at high power ratings is very far from 1. THat is the flaw of the simple calculations. Air mass flow is not dependant of the fuel flow except the effect of mixture cooling especially if you atomise it before the charger (less T - more pressure ratio) but in the working range of alpha changing this effect is negligeble.

 

 

7= (10.4/1)/14.9

10,972/1055

Convert to Standard cubic feet per min

Mass flow = Fuel flow(pph) * 3.246

3418 Scfm =1055 * 3.246

 

Air mass has rise with alpha, you hit a series of limiting returns at this point. If you wanted peak power, you'd be better off enriching the mixture. As your Mass air flow would be come realistically achievable.

 

 

Before auto mix systems pilots tended to run to rich, because they thought it would give them more power. Though they easily could end up with less power than their planes we're capable of producing, trying to dump gas into a craft who's beyond the VE to use it. This also lead to maintenance nightmares for ground crews. As running rich would tend to cause issues with plug fouling, ect.

Ніщо так сильно не ранить мозок, як уламки скла від розбитих рожевих окулярів

There is nothing so hurtful for the brain as splinters of broken rose-coloured spectacles.

Ничто так сильно не ранит мозг, как осколки стекла от разбитых розовых очков (С) Me

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Yes, it's not. The basic is the actual air mass flow, but alpha affects to the slight power changing.

By the way, comparing power peak at alpha=0.85 and power deviation within alphaMax/alphaMin~2 , the power deviations will be less than 10%

How is power derived from Alpha, what is the relation of alpha to power?

 

You can not use this equation because alpha at high power ratings is very far from 1. THat is the flaw of the simple calculations. Air mass flow is not dependant of the fuel flow except the effect of mixture cooling especially if you atomise it before the charger (less T - more pressure ratio) but in the working range of alpha changing this effect is negligeble.

That is a calculation of the mass of the required airflow needed to achieve the mixture strength at a given a fuel flow. It is not a calculation of the actual airflow inside the manifold.

 

Mixture setting (Air mass/Fuel Mass) is the determinate of power output of combustion. Power output of combustion is the determinate of engine power output. A mixture of setting of 12.5 produces more power than a mixture setting of 14.9.

 

Therefore, to determine the needed airflow of an engine at a given power setting and mixture strength; One observes fuel flows needed to derive power at the given fuel air mixture settings. From there you can calculate airflow needed.

 

Gasoline also has limits on where where it is combustible. At sea level gasoline will not ignite if it is less than 1.7 % of the mixture. It also won't ignite if it's more than 7.5% of the mixture. As altitude increases and the air gets thinner and cooler those numbers increase.

 

At alpha of .0011 there should no longer be combustion in the engine.

.0011=(.017/1)/14.9

.0011=(.034/2)/14.9

 

And before alpha=.0011 power should be dropping rapidly.

 

Back to issue of BSFC, which is where all this started. If you alter fuel flows you have to recalculate BSFC.

 

Assuming a base fuel flow of 1055 and constant power output of 1770 hp at 3250, 2136 inch Displacement.

Doubling the fuel flow takes the BSFC to 1.192, from .59. Thus resulting in a rise of the VE of the engine need to achieve the same power.

 

2.86= ( 9411 x 1770 x 1.192) / (2136 x 3250)

 

If the mixture ratio stays the same and you double fuel flow, VE goes up more than double, 1.41 was base. VE is an expression of how much air compared to the volume of the cylinders, is needed for the power output of the engine. It allows us to reasonably evaluate the performance of an engine. At those fuel flows and that mix setting, for that power, you have to put a volume of air that is 2.86 times the volume of the cylinders in.

We can then compute the sea level manifold pressure necessary to archive this.

 

VE * 29.92 = Manifold absolute pressure in inches of mercury, HG.

As 2.86*29.92= 85.5712 inHG

Convert HG to ATA 85.5712/28.95 = 2.95 ATA

 

It doesn't look reasonable, knowing the limits of forced induction the engine's capacity to sustain those pressures. VE and TE are great tools for evaluating the performance of an engine. Which is where this whole thing started. The debate was, does cooling provide a reasonable means to increase the horsepower of the Jumo by 100. By showing that only marginals gains in thermal efficiency we're need. I showed it was reasonable to say additional cooling is an efficient means to derive 100 hp.


Edited by Curly
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When the oficial is finish i will try translate for PT-BR.

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  • ED Team
From DCS manual, page 29:

 

The tanks are daisy-chained and fed into one another.

 

No, they don’t fed into one another. Front and rear fuselage tanks fed into the engine’s main pump.

 

Page 31:

 

When drop tanks are used, the Fuel Selector Switch should be set to “Hinten”. The Fuel Contents Gauge will continue to display full for as long as the drop tanks continue to feed the rear and in turn the forward tanks. Once the drop tanks are emptied, the fuel quantity in the rear tank begins to decrease.

 

Unfortunately things are not that simple. First, the rear tank doesn’t feed the forward tank. It can’t. As I said above, both fuselage tanks can only feed the engine pump. Actually there is no piping whatsoever between the front and rear fuselage tanks. This is true for any Fw 190 ever built, from A-1 to D-9, as the technical manuals clearly show.

 

Second, the fuel quantity in the rear tank won’t show full, then begin to decrease after the drop tank is empty. That is not how it works.

 

The pipe that feeds from the drop tank to the rear tank actually connects to a special limiting valve, mounted in the rear tank. If the plane carries a drop tank, that limiting valve will only open when the rear tank content drops below 240 liters.

 

So, if a drop tanks is used, fuel consumption order would be like that:

At first, no fuel is consumed from the drop tank, because the limiting valve is closed. So in the beginning fuel will be consumed from the rear tank, until its level drops to 240 liters. Only then, the limiting valve will open and allow fuel from the drop tank to feed in to the rear tank. When the drop tank is empty, the fuel level in the rear tank will drop below 240 – this is the indication that the drop tank is empty.

 

Since the fuel system from D-9 is practically identical with A-8, I suggest ED to check Fw 190 A documentation from http://www.luftfahrt-archiv-hafner.de/

 

In the docs there is a manual, Bedienungsvorschrift-Fl with pilot instructions for all Fw 190 A version, from A-1 to A-8. How the fuel selector and pumps switches should be used is clearly described. The entire part about fuel system usage by the pilot covers several pages, so what’s in DCS manual is only scratching the surface.

 

Very short summary about fuel system use from the instructions – when a drop tanks is attached, in the beginning the forward fuselage tank fuel pump shouldn’t be switched on. Fuel from the forward tank will still feed the engine pump (on condition the fuel selector is on “Auf”, that is how it should be), but it will feed only due to gravity, so at a much slower rate than the rear tank, with its pump on. Necessary for correct center of gravity position. When the drop tank is empty, switch its pump off, and switch on the forward tank fuel pump. Next, when the white warning light for rear tank 10 liters is on, close the rear tank with the fuel selector, rear tank pump off, switch indicator to forward tank.

 

But what if there is no drop tank, the forward tank pump is on, so most likely the forward tank 90-100 liter level light will go on first? Close the forward tank with the fuel selector and empty the rear tank, then close the rear tank, rear pump off. As a general rule, once a fuel tank is empty, it must be closed with the fuel selector, to avoid air from the tank reaching the engine’s main pump.

Thanks for corrections.

Единственный урок, который можно извлечь из истории, состоит в том, что люди не извлекают из истории никаких уроков. (С) Джордж Бернард Шоу

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metal blades on VDM VS 111?

 

Hi,

 

dont get me wrong i only wanted to clarify this, may be that i misunderstood it.

 

On page 27 it says that the "three bladed VDM VS 111 constant speed propeller with metal blades".

 

What does thie mean? Full metal or only metal sheets?

 

To my knowledge the Doras and even the Tank 152 had wooden propellers. (VS9 and VS111)

This was because of shortage and second, the engine was not desrtoyed or severed damaged after an emergency landing.

There is an statement of an pilot(dont ask me wich side it was) in "Mit Fw 190D-9 im Einsatz." from Axel Urbanke.

 

On the last pages ( side 441 onward, Mit Fw 190D-9 im Einsatz.", Axel Urbanke) there are some great colored photos of the FW 190D-9, black 8, Wk.Nr 210968, after lifting her from Lake Schwerin in the 1990.

Here is the website.

 

http://daedalus-berlin.de/index.php%3Foption%3Dcom_content%26task%3Dblogsection%26..

 

 

Hope the devs can help me to clarify this.

 

Thank you very much

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  • ED Team

There are mistake in the manual. Blades are wooden.

Единственный урок, который можно извлечь из истории, состоит в том, что люди не извлекают из истории никаких уроков. (С) Джордж Бернард Шоу

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66.gif

 

 

Drehzahl = Rotational speed or RPM

größer = more >>>> ED Flight Manual >>> Gröber / coarse

kleiner = less >>>> ED Flight Manual >>> Fein / fine

 

This is 100% wrong in the Flight Manual of ED.

"Blyat Naaaaa" - Izlom

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66.gif

 

 

Drehzahl = Rotational speed or RPM

größer = more >>>> ED Flight Manual >>> Gröber / coarse

kleiner = less >>>> ED Flight Manual >>> Fein / fine

 

This is 100% wrong in the Flight Manual of ED.

 

A better translation in the context of Drehzahl/Rotational speed (RPM) would be:

 

größer = higher

kleiner = lower

 

MAC

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If I understand correctly, Isegrim wanted to note that meaning of terms has been reversed - you need fine pitch to get higher RPM and coarse pitch to get lower RPM (it seems to be the other way around in the manual?).

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If I understand correctly, Isegrim wanted to note that meaning of terms has been reversed - you need fine pitch to get higher RPM and coarse pitch to get lower RPM (it seems to be the other way around in the manual?).

 

 

No!

The Word *Drehzahl* means Engine speed and not Propellor pitch angle.

 

And now find a Formula 1 Driver and ask him how Coarse his Engine speed is when he should shift into the next Gear! And How fine when he should shift into the pevious one.

 

The Translation is simply wrong thats all.

 

 

Edit: And its reversed also Higher RPM (Größer) = less Propellor pitch angle. Also an ß is not an B .


Edited by Isegrim

"Blyat Naaaaa" - Izlom

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IMO while technically the higher/lower RPM is more correct translation for German terminology, but its also seems somewhat alien to English terminology - isn't coarse/fine propeller pitch (which is really just a different description of the same thing) a more commonly used term?

 

PS/OFF: "ß" can be a pain reproduce, the ASCII code evades me... btw weren't the special German characters supposed to be "withdrawn from service" in grammar reform..?

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Vezérünk a bátorság, Kísérőnk a szerencse!

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IMO while technically the higher/lower RPM is more correct translation for German terminology, but its also seems somewhat alien to English terminology - isn't coarse/fine propeller pitch (which is really just a different description of the same thing) a more commonly used term?

 

PS/OFF: "ß" can be a pain reproduce, the ASCII code evades me... btw weren't the special German characters supposed to be "withdrawn from service" in grammar reform..?

 

When speaking of prop pitch, "coarse/fine" is correct in English aviation terminology, but when speaking of RPM "higher/lower" is better IMO. One thing describes the means, the other the aim.

 

MAC

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  • ED Team
When speaking of prop pitch, "coarse/fine" is correct in English aviation terminology, but when speaking of RPM "higher/lower" is better IMO. One thing describes the means, the other the aim.

 

MAC

 

I guess "coarse" and "fine" grow from the variable pitch propellers. THen, as the prop governors began to maintain the rpm, "low" and "high" appeared.

 

By the way, in Russian we still have these old variable pitch prop terms even applied to the prop governor... it's a unexhaustable source of misunderstanding... :)

Ніщо так сильно не ранить мозок, як уламки скла від розбитих рожевих окулярів

There is nothing so hurtful for the brain as splinters of broken rose-coloured spectacles.

Ничто так сильно не ранит мозг, как осколки стекла от разбитых розовых очков (С) Me

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I am missing in manual some info about the EZ42 Gunsight Adjustment Unit on right console . According to EZ42 manual(page 13) is used to adjust gunsight ballistic for proper combat altitude(values are in table on adjustment unit). Also is missing info (and maybe also programing) you need to switch on gunsight at least 1,5min before combat to ensure right function of both gyroscopes (they need time to be in proper position according to EZ 42 manual page 13). Also is missing EZ42 self-destruction button/detonator (EZ 42 manual page 11), I don't know if there is evidence of its position in FW 190 cockpit. See picture position 55, sorry if translation is not OK I am not native speaker neither German or English….

 

 

Have you already consider this??? It was maybe litlle bit lost in midlle of MW50 batlle :thumbup:

 

In meanwhile I think as EZ42 self-destruction was propably used same button like for FUG25, what make sence (but still guessing)...But this is not important towards cockpit functionality....

[sIGPIC][/sIGPIC]

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Sorry for my English.

I don't seen in manual, how long I can use MW50 in fly? What altitude to use it?

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The increased power could be used for a maximum of 10 minutes at a time

 

Thank you. It means 10 min, then cooling and use again? Or I can use it once.

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Thank you. It means 10 min, then cooling and use again? Or I can use it once.

 

10 minutes at a time, with reduced power to cool down the engine for 5 minutes in between. The D-9 carried enough MW-50 for 45 minutes (though in practice it was more like 40 minutes).

 

You have enough MW-50 to run it 4x10 minutes. You would run out of fuel before you'd run out of MW-50.

FW 190 Dora performance charts:

http://forums.eagle.ru/showthread.php?t=128354

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Sorry for my English.

... What altitude to use it?

 

MW50 was used from start, up to the critical height (Volldruckhöhe) of the engine. The Jumo had a critical height of approx. 5500m - 6000m.

 

Beyond that, there was no or little effect, i think.

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10 minutes at a time, with reduced power to cool down the engine for 5 minutes in between. The D-9 carried enough MW-50 for 45 minutes (though in practice it was more like 40 minutes).

 

You have enough MW-50 to run it 4x10 minutes. You would run out of fuel before you'd run out of MW-50.

 

Thanks.

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MW50 was used from start, up to the critical height (Volldruckhöhe) of the engine. The Jumo had a critical height of approx. 5500m - 6000m.

 

Beyond that, there was no or little effect, i think.

 

Higher then 5500m - 6000m MW50 will not give effect?

Where I can read it, some manual or somthing else?

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Above 5000m MW-50 starts losing it's effectiveness.

 

See here:

38961d1299764722t-erich-jumo-213e-data-jumo213a1.jpg

Jumo_213A_power_graph.jpg

attachment.php?attachmentid=88177&d=1379583084

 

Thanks.

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  • ED Team

Corrected Flight Manual in the first post.

Единственный урок, который можно извлечь из истории, состоит в том, что люди не извлекают из истории никаких уроков. (С) Джордж Бернард Шоу

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