Author Topic: BMW801D2 Horsepower at 1.62ata (Read 8728 times)

GScholz · « **Reply #15 on:** July 28, 2004, 01:08:39 PM »

MiloMoron please, just go away.

GODO · « **Reply #16 on:** July 28, 2004, 01:39:34 PM »

Not exactly sure about the importance of HP or PS alone without propellor efficiency, exhaust thrust, weight and drag factors.

phookat · « **Reply #17 on:** July 28, 2004, 04:06:00 PM »

Presumably all these elements individually feed into the FM.

GScholz · « **Reply #18 on:** July 28, 2004, 04:16:01 PM »

I don't think any of those elements feed into the FM. I believe Pyro uses the speed/climb chart data directly. How much Hp the plane had is inconsquensial.

phookat · « **Reply #19 on:** July 28, 2004, 06:05:19 PM »

Hmm, OK. That surprises me, I'd have thought the FM started from something closer to first principles...

GODO · « **Reply #20 on:** July 28, 2004, 06:13:23 PM »

Too advanced FM aproach phookat

MiloMorai · « **Reply #21 on:** July 28, 2004, 06:45:49 PM »

Looks like the incorrect boost number is not going to be corrected.

The correct number is 1.58/1.65. (low/high gear)

Crumpp · « **Reply #22 on:** July 28, 2004, 06:49:20 PM »

Right it doesn't matter as far the FM is concerned. I would just like to know.

Crumpp

Crumpp · « **Reply #23 on:** July 28, 2004, 07:43:03 PM »

Quote

MiloMoron please, just go away.

My God we agree on something!

Crumpp

GScholz · « **Reply #24 on:** July 28, 2004, 07:56:51 PM »

We agree on many things ... we just like being opponents too much to talk about them.

Crumpp · « **Reply #25 on:** July 28, 2004, 08:01:45 PM »

Let me clarify the boost settings on the 190A as I get them from the manual along with the Weights. All wieghts include full load of ammo, fuel, lox, winterization kit, and a 100kg pilot onboard.

All are Normaljager with full wing armament.

FW-190A3 - 3978kg

3 min @ 1.42ata

30 min @ 1.32ata

FW-190A5 - 4106kg

same as the A-3 when not equipped with C3

With C3 - 10-15 min @1.65ata

FW-190A8 - 4272kg (includes 115 aux tank)
4152kg Without aux tank

10 min @ 1.65ata

unlimited @ 1.42ata

With C3

"as long as the emergency lasts" @ 1.65ata

Milo is correct on the 1.65ata. Reading all these different Manifold pressures with most of them ending in "2" I wrote down the wrong thing in my notebook.

It is interesting that Fabers 190A3 was tested using 1.32ata at 2400U/min (report says 1.35ata in some places but I think it is a typo) with the exception of the speed runs which were conducted at 1.42ata at 2700U/min for 3 minutes.
The Spifire MkIX used (+15) boost at 3000 rpm.

Does anybody know the Hp rating of the BMW 801 @ 1.65ata.

GScholz · « **Reply #26 on:** July 28, 2004, 08:21:31 PM »

The only references I could find:

Quote

Btw. Fw190A-8 engine is the same as in 190A-4. BMW 801D-2.

It has "increased power setting" Erhöhte Notleistung which brings 1.65ata boost pressure and 2100PS power. But physically engines should be similar.

I think currently La-5FN and Fw 190A-8 relative performances are well made.

Fw 190A-8 takeoff weight 4300kg. (pilot included as 100kg)
Fw 190A-8 maximum power 2100PS / 2070hp / 1544Kw
Power weight ratio 0.49 PS/kg

La-5FN takeoff weight 3265kg. (not sure if pilot included)
La-5FN maximum power 1875PS / 1850hp / 1379Kw
Power (PS)/weight(kg) ratio: 0.57 PS/kg

So you see that with normal takeoff load La-5FN should be superior in acceleration compared to Fw190A-8.

With both planes at low fuel they would be about equal power/weight wise. And so accelerate almost in similar fashion.

http://forum.wbfree.net/forums/archive/index.php/t-22948.html

Quote

Hi Badger,

>AFAIK theoretically it can be easily calculated from basic engine parametrs

It can be determined graphically from the engine chart you posted.

The speed chart shows that the full pressure heights at increased boost are 700 m for low gear and 5500 m for high gear at top speed. One can simply extend the "drop off" legs of the high-speed power graph to this altitude to get the power output.

I get the following values for high speed flight (numbers in brackets for original boost):

0700 m: 2000 HP (1745 HP)
5500 m: 1610 HP (1435 HP)

For climb:

0300 m: 1970 HP (1810 HP)
4900 m: 1670 HP (1475 HP)

Regards,

Henning (HoHun)

http://forum.wbfree.net/forums/archive/index.php/t-12005.html

Crumpp · « **Reply #27 on:** July 28, 2004, 08:57:03 PM »

That 4300kg weight is the maximum take off weight for the "H" chart. It is referred too in several locations. All the Flugzeug-Handbuchs have them for each version and they are labeled in big bold letters "max take off weight" listing several weights and "H" categories.

There are also data cards with completely different weights listed for each variant including weight for ammo by weapons system, winterization kits, armour, radios, oil, fuel, and a pilot weighing 70-100kg. The weights for each version are broken down from basic airframe to the A/C sitting on the runway

In the maintenance manual there is a large "H" chart with every version and Rusataz listed.

Kind of confusing until my friend who helped me with the translations pointed out in the control adjustment chapter of the maintenance manual the OTHER "H" chart. It's a column in the control surfaces data card and gives the adjustments for the fixed trim tabs corresponding to each "H" category.

In other words a fully loaded FW-190A8 with a 100kg pilot could add 28 kg of Champagne and Lobsters in the back without having to change the fixed trim tabs.

Crumpp

GScholz · « **Reply #28 on:** July 28, 2004, 09:04:38 PM »

Hehe, now don't go and derail your own thread. It's the 1.65 ata that's important.

You could email Hafner at the Luftfarhrt-Archiv and ask if they've got any reference to the 1.65 ata boost in any of their BMW801D documents, and offer to buy it if they find it. Unless of course you've already bought them all.

Crumpp · « **Reply #29 on:** July 28, 2004, 09:09:13 PM »

Good idea. Thanks for finding that thread.

Crumpp