BMW801D2 Horsepower at 1.62ata

[Crumpp]

March was very early in the FW-190A8 deployment life cycle.

The message was sent out in Jan'44.  Being in the Military myself, I have to say that most military manuals have corrections and supplemental data printed.  I am not surprised.

You do know that Pyro is redoing the FW-190 Flight Model in AH?

I have sent him several pages out of the manuals.

Check out the BMW-801D Horsepower chart on the FW website I listed earlier.  Hohun claims to have a chart that shows 2100PS at full throttle height for 1.58ata @ 2700U/min.  You wouldn't happen to have a copy?  Makes sense because it is a linear progression.

Crumpp

[sfuchs]

Sorry, I checked some books but no one has a chart with figures of the BMW 801 D at 1,58 / 1,65 ata. Perhaps there are more informations in the engine manual ?

- sfuchs -

[Crumpp]

I got the BMW 801 MA- BMW801ML, BMW 801C, and BMW 801D Handbuch und Teiluberholungsanleitung Mai 1942 190 Seiten.


It has no power information at all in it.  Has a really cool diagram of the the motor though!

Since it is 1942 and the BMW801D2 was not rated for 1.58ata/1.65ata it is on no use.

Thanks for looking though!

Crumpp

[niklas]

Originally posted by Crumpp
The tank was optional in the FW-190A8.  The manual is clear on that.

Crumpp

Agree. But without aux fuel tank i´m sure that the extra boost wasn´t available, too!!

niklas

[GScholz]

Originally posted by niklas
Agree. But without aux fuel tank i´m sure that the extra boost wasn´t available, too!!

niklas

Why? The C3 system drew fuel from the engine fuel line, not from any specific tank.

[Crumpp]

Actually it was available without the 115 liter Aux tank.  C3 "erhöhte Notleistung" had nothing to do with the fuel system set up and drew fuel from any fuel tank.

All the Aux tank did was give about 7 1/2 minutes more. It was not a very popular addition for fighters.  Now when equipped with GM-1 LNOX system you had to have it on board.  Not much use in AH for GM-1 though. I think the aux tank should be an option in the hanger.

I also think the R7/R8 armour with GM-1 should be an option too.  Great for scenario high alt buff hunting.

Luftwaffe Wgr. 21 rocket tube need to be jettisionable too.  They were in reality.

Crumpp

[sfuchs]

I once again checked the Flugzeughandbücher. There is an additional part in the manual of the Fw 190 A7/A8 that ist dated august 1944. That part makes things a bit clearer.

There are two completely different systems for the increased emergency boost. The first one as used in several 190 A5 (mostly jabos) worked with C3 injection and was only available up to 1 km.

The second system as used in the 190 A8 worked different. The manual reads "Anlage für erhöhte Notleistung (ohne C3 Einspritzung)" ... that means "system for increased emergency power (without C3 injection)". It could be run for 10 minutes and uses 1,58 ata for the low gear and 1,65 ata for the high gear, both at 2700 rpm.

That there were two completely different system makes sense for me, I've read somewhere in the manuals that the C3-injection wasn't useful in heights above 1 km, it was only waste of fuel without gaining significantly more power (I must look up the exact passage in the manual), therefore I was confused that this system later should have been cleared for high gear. I think the clearance from BMW from january 1944, that niklas mentioned, was for the second system, which was obviously more effective - up to full pressure height in high gear.

In the manual of the 190 A7/A8 is no remark that the 115 litre tank was necessary for the installation of "increased emergency power (without C3 injection)", but it mentions that the emergency power burns more fuel (of course) ... so it might have been logical to install the additional 115 litre tank.

@Crumpp
Can you tell me more about the engine manual of the BMW 801 ? I thought about buying it. When there are no power charts in it, is there possibly something else of interest ? Except the diagram of the engine ?

- sfuchs -

[Crumpp]

It's not worth it to get the BMW 801 manual unless you just want to know details about the working and operation of the Engine.  C3 erhöhte Notleistung was cleared for higher altitudes meaning it was installed on Jager as well.  It did burn an ungodly rate of fuel.  70 liters in 5 minutes.

The increased emergency boost was later cleared from BMW for the high alitutude gear, too (BMW Note from 20.01.44). You have to know the exact dates of the manuals. When they were pre-44 they´ll probably speak about the 1000m limit, even when they mention the A8 project

The 115 liter aux tank would make sense if you were using C3.  However leaving just the tank in the hanger makes the 190's choices much more realistic.

Crumpp

[Crumpp]

C3-injection wasn't useful in heights above 1 km, it was only waste of fuel without gaining significantly more power (I must look up the exact passage in the manual),

From what I read C3 did not increase the Manifold pressure.  It simply worked to keep the heads from overheating.

Crumpp

[sfuchs]

Originally posted by Crumpp
From what I read C3 did not increase the Manifold pressure.  It simply worked to keep the heads from overheating.

It was a combination ... of course you don't get a higher manifold pressure by simply injecting C3 ... but when the increased emergency power with c3-injection was activated, the mechanism behind the system lets the "throttle flaps" (sorry I don't know the correct term for the german "Drosselklappe") open so wide at heights under 1 km, that a maximal manifold pressure of 1,65 ata was achieved - instead of 1,42. The injection of C3 was necessary, because the normal injection pump didn't get enough fuel in the cylinders to operate the engine at 1,65 ata ... therefore additional fuel was injected on a seperate way.

- sfuchs -

[sfuchs]

I've found the passage about the c3 injection I mentioned before ... it is part of the Bedienungsanleitung. The passage says that the useage of increased emergency power is only allowed when in low gear. Near ground-level the system is most effective, in 1000m still 1,5 ata can be achieved, in heights above 1000 m the gain of power is only low and therefore the useage is only allowed up to 1 km. When the manifold pressure drops under 1,5 ata the increased emergency power has to be deactivated, because it burns to much fuel for the small gain of power.

Fuel consumption when on increased emergency power at 1,65 ata / 2700 rpm is about 70 litres in 5 minutes (840 litres / 1 h).

This covers the system that was used in several 190 A5 ... it is a different system as in the 190 A8 ("increased emergency power without c3-injection"). It is obvious that the system is useless in heights above 1 km, while the system of the 190 A8 is effective up to full pressure heigth in high gear.

- sfuchs -

[Crumpp]

It was a combination ... of course you don't get a higher manifold pressure by simply injecting C3 ... but when the increased emergency power with c3-injection was activated, the mechanism behind the system lets the "throttle flaps" (sorry I don't know the correct term for the german "Drosselklappe") open so wide at heights under 1 km, that a maximal manifold pressure of 1,65 ata was achieved - instead of 1,42. The injection of C3 was necessary, because the normal injection pump didn't get enough fuel in the cylinders to operate the engine at 1,65 ata ... therefore additional fuel was injected on a seperate way.

Yes that is correct for the 190A5's system.

[gwshaw]

I did a quick work up on the 801D using the USN/USAAF test data as the starting point.

The data I have gives 1755 hp @ 3250 ft (I'm calling it 3280 ft, or 1 km) & 1.42 ata.

That works out to a blower pressure ratio of 1.60:1, naturally giving 1.60 ata @ SL. So that gives a SL static max of 1.60 ata, 1955 hp +- 1%. Call it about 1980 hp, about 2010 ps (1980 * 1.014).

With ram 1.65 ata should be easily attainable at SL, giving about 2070 ps (1.65/1.60 * 2010), but that is before taking ram heating into account.

We will make this easy and do it at 200 mph TAS:

200/100 ^ 2 = 4 C temp increase

SL temp is 288.36 C, rammed temp is 292.36

sqrt (288.36 / 292.36) * 2070 = 2055 ps

But, another but , C3 injection should lower charge temp anywhere from 10 to 25 C.

At 10 C decrease:

sqrt (302.36 / 292.36) * 2055 = 2090 ps

At 25 C decrease:

sqrt (317.36 / 292.36) * 2055 = 2140 ps

So, rammed performance of 1.65 ata, 2100 ps with C3 injection is just doable at SL, when rammed. Unrammed should be about 2010 ps 1.60 ata, or about 1985 ps at the 1.58 ata given in other figures.

Greg Shaw

[Crumpp]

Thanks Man!

Your the heat.

Crumpp

[Crumpp]

Sfuchs,

See what you can find out about the Winterization Kit.  From what I read it is an adaptation for sub-artic conditions to keep the oil from freezing.  

It's a larger capacity oil pan with a greater quantity of oil.  It also has room to put a couple of liters of C3 directly into the oil pan and includes an additional pump for that.

It gets kind of technical for my level of German, sometimes.  

Thanks!

Crumpp