Engine info needed

[gwshaw]

I am working on a new engine model in Excel. My current one works well if I have good power, MAP and altitude figures. I am working on a lower level model that I can plug basic stats into and come up with some ballpark figures to plug into my existing model.

I need the following information for the BMW 801:

(What I already have in parentheses)

bore
stroke
compression ratio
manifold pressure - (1.32, 1.42, 1.58, 1.65)
rpm (2700, 2450)
blower diameter
blower gear ratios {both gears}

I would like to work it out for both the BMW 801C & 801D

The same info for the DB 601, 603 & 605 would be appreciated as well.

Greg Shaw

[VO101_Isegrim]

bore : 156mm / 6.15 inch
stroke  156mm / 6.15 icnh

compression ratio :
C: ?
D: 7.22 to
 1
manifold pressure - (1.32, 1.42, 1.58, 1.65)

C:
Not :1.32/2700
Kampf : 1.25/2400
D :
Not : 1.42 or 1.56 (low gear) or 1.65ata (high gear) / 2700
Kampf: 1.32/2400

2450 rpm only for derated 801D!!!

blower diameter  - ? a 24 blader, it is

blower gear ratios {both gears}
C :  5.07 and 7.46
D : 5.31 and 8.31

801C runs on B-4, 801D on C-3 (IIRC)

Hope this helps. Do you have an aviation website perhaps, or is it for your own fun?

[MiloMorai]

Greg,

the 801 used 6.5 in the early model, to 7.2 in the D model, to 8.3 in the later T models.

[gwshaw]

Thanks for the information.

I don't have a website yet, most of what I'm working on doesn't lend itself to a webpage. Once I get the math working it might write up a ruby script to do the calculations.

In short this is what I'm trying to do.

If I know the blower diameter, gear ratio and engine rpm I can calculate the blower tip speed. From there I can guesstimate a range of blower efficiencies and from there get a range of blower pressure ratios. Since I already know the rated altitudes for the BMW 801 I can calculate blower %, although that isn't necessary for any further calculations.

I know the swept volume, the backpressure, the charge pressure, compression ratio and ambient temp at whatever the altitude. From the impeller tip speed I can calculate the temp rise and hence the charge temp. That gives me the charge consumption.

That should be enough to get a good ballpark figure for indicated power (IHP). Since I now know the charge consumption and the heat rise in the supercharger I can calculate the blower power requirements. Friction losses should be roughly 15% of IHP, subtracting friction losses and blower power from IHP should give a fairly accurate BHP figure.

A little bit of curve fitting should get it to match historical results. Once I get everything working I should be able to plug in other engines and get decent ballpark figures.

Greg Shaw

[Crumpp]

That is good stuff bro!

Hey BTW you do know that 2100PS I gave you is NOT Horsepower?  I have to check if you gave me back figures in PS or Hp.  

You probably know that already.

Crumpp

[MiloMorai]

Basic technical aspects of the DB 605.

- 60 degrees inverted V-12, pressure-cooled

- bore: 154 mm, stroke: 160 mm, total volume: 35,7 litres

- compression ratio: 7.5/7.3 (87 octane), 8.5/8.3 (96 octane)

- length: 2303 mm, height: 1050 mm, width: 762-845 mm

- dry weight: 730 - 745 kg, built-in weight: 764 - 815 kg

- 4 valves per cylinder, 1 overhung camshaft

- direct fuel injection

- single-stage variable speed mechanical compressor driven via a barometricly controlled hydraulic clutch (the DB 605L had a two-stage compressor)

- rpm: max. 2800, climb: 2600, max. cruise: 2300

http://w1.1861.telia.com/~u186104874/db605.htm#basicaspects

[gwshaw]

I found some more of the blower information in some of my notes.

DB 601a - 10.25 in (26 cm) @ 10.39:1 2400 rpm min slip - 1115 fps
DB 601e - 10.25 in (26 cm) @ 10.07:1 2700 rpm min slip - 1216 fps
DB 605a - 10.48 in (26.6 cm) @ 10.07:1 2800 rpm min slip - 1289 fps
DB 605as/d - 12.2 in (31 cm) @ 10.07:1 2800 rpm min slip - 1501 fps

BMW 801C - 13.25 in (33.7 cm) @ 5.07:1 2700 rpm low - 791 fps
BMW 801C - 13.25 in (33.7 cm) @ 7.46:1 2700 rpm high - 1164 fps

BMW 801D - 13.25 in (33.7 cm) @ 5.31:1 2700 rpm low - 829 fps
BMW 801D - 13.25 in (33.7 cm) @ 8.32:1 2700 rpm high - 1299 fps

Still need max slip values for the DB engines, but I think I have everything I need for the BMW 801 series.

Greg Shaw

[VO101_Isegrim]

Originally posted by gwshaw
I found some more of the blower information in some of my notes.

DB 605a - 10.48 in (26.6 cm) @ 10.07:1 2800 rpm min slip - 1289 fps
DB 605as/d - 12.2 in (31 cm) @ 10.07:1 2800 rpm min slip - 1501 fps

Greg Shaw

Greg, are those AS/D values certain? Especially the gear ratio! I am asking because I am building a technical site on the 109K/605D and would like to present all information on them possible with the greatest accuracy.

I would be very grateful for any information on that topic if you could send me..

[gwshaw]

The figures came from the reprint of the USAAF guide to German aircraft. I believe they came from captured examples, but my copy of the book is still in storage from my recent move.

German Aircraft and Armament: Informational Intelligence, Summary No. 44-32
October 1944 (Informational Intelligence Summary)

Amazon is currently sold out, but they do have it in their lists.

Greg Shaw

[VO101_Isegrim]

Does it have anything on the 109K ?

[gwshaw]

Originally posted by VO101_Isegrim
Does it have anything on the 109K ?

I don't believe so, but as I said my copy is in storage currently. I doubt that the USAAF had captured any bf 109K by October 1944. Although I wouldn't be surprised if they had captured a DB 605AS, or at least documentation by then.

It has data for the Bf 109E, F and G, apparently the same 20 mm equipped 386 mph G-6. There is some addendum info for MW50, GM1 and enlarged blower versions.

I'm a little leary of the diameter, I always thought the AS/D used the impellor from the DB 603, but the DB 603 is listed with a diameter of 11.61 in (29.5 cm).

Greg Shaw