Performance/Endurance of Bf 109 G-6 during aerial combat - questions for experts!!!

[Kurtl12]

Gentlemen,

Now I have a question for real Bf 109 experts: Please figure out an field aerodrome in 1944, base of a 109 unit. The planes are getting fuel on ground while suddenly Lightnings appear overhead the field. The group commander asks for an immediate take off. Drop tanks has to be dropped shortly after the take off because the P-38 Lightnings are still around. As a pilot of that group you find yourself in the middle of a dog fight. You are sitting in a Bf 109 G-6, your main tank is full so you have about 400 liters left. Your drop tank is gone...

A.) What is your maximum range you can fly out under such circumstances if you have to return to the same base?
B.) What is your maximum endurance in the same situation?

Thanks for an active discussion! - Kurtl

[Oberst]

Based on what I know, and what Luftwaffe pilots I've spoken with told me, albeit not in absolute terms, about 300km & 60mins based on your criteria. Though not necessarily hunting P-38's, and dependant on E/A altitude.

[Juha]

I agree with Oberst, 109 G-6, DB 605A engine, 1944: 400L fuel tank, take-off and emergency power 1475 Ps (a bit smaller unit of power than anglo-american hp used by Germans) max allowed time for continuous use 3 min, consumption 480L/h, climb and combat power 1310 Ps, max allowed continuous use 30min, consumption 400L/h, max continuos power 1075 Ps, consumption 320L/h, all figures are those at SL, at FTH (5500-5800m) figures were 1355, 1250 and 1080 Ps and 450, 390 and 320L/h.

Juha

[Kurtl12]

Cool. So the endurence would be about 1 hour +. I guess the radius around the base would be about 200km if you think about to attack the enemy aircraft at all heights. - Kurtl

[Kurfürst]

You can work out the details for just about any combination using the F-4 range table at Beim Zeugmeister - the G-6 had very similiar :

http://www.beim-zeugmeister.de/zeugm...are%20found%3B

It should be pretty simply assume a full tank, as in your example, of 400 liters. Say 3 minutes is spent on maximum power, 1475 PS, that is 480 lit consumption per hour, or 24 liters in 3 minutes. Say another 10 minutes is spent 30 minute rating - 400 liters/h - which is another 67 liter consumed. That is 91 liter in total, leaving 309 liters for other purposes.

The F-4, at the engine power best for range consumed 120 liter/h, and could fly 315 km/h at 1 km altitude while doing so. 309/120 is 2,57 h duration, during which the aircraft can cover 2,57 x 315 = 811 km. So, about 400 km radius in an optimum case, or 300 km radius for a pretty safe bet.

[drgondog]

Originally Posted by Kurfürst

You can work out the details for just about any combination using the F-4 range table at Beim Zeugmeister - the G-6 had very similiar :

http://www.beim-zeugmeister.de/zeugm...are%20found%3B

It should be pretty simply assume a full tank, as in your example, of 400 liters. Say 3 minutes is spent on maximum power, 1475 PS, that is 480 lit consumption per hour, or 24 liters in 3 minutes. Say another 10 minutes is spent 30 minute rating - 400 liters/h - which is another 67 liter consumed. That is 91 liter in total, leaving 309 liters for other purposes.

The F-4, at the engine power best for range consumed 120 liter/h, and could fly 315 km/h at 1 km altitude while doing so. 309/120 is 2,57 h duration, during which the aircraft can cover 2,57 x 315 = 811 km. So, about 400 km radius in an optimum case, or 300 km radius for a pretty safe bet.

Hello Kurfurst - do you happen to have any Bf 109G/K performance tests which include rated Hp at critical altitudes along with the speeds attained?

[Kurfürst]

Originally Posted by drgondog

Hello Kurfurst - do you happen to have any Bf 109G/K performance tests which include rated Hp at critical altitudes along with the speeds attained?

Hi Bill!

You can find the details on my site: http://kurfurst.org/
You can find the relevant engine output (in all cases, static power) here: http://kurfurst.org/#engines

The tests themselves note the power regimes, so its a matter of putting 2 and 2 together.

But a quick recap - I am not sure what G types are you interested in, or is it cruise/max power, SL or rated alt?

Anyway, here it is:

G-2 (605A) - Mtt. calculation/official figures for early type:
max. 537 kph @ SL, 660 kph @ 7000m. 1310/1250 PS (static)*
max cruise. 600 kph @ 6000m, 1090 PS (rammed), 225 gram/PS/h fuel consumption

G-6 (605A) - flight trials:
510 kph @ SL, 625-630 kph @ 6700m. 1310/1250 PS (static)*
530 kph @ SL, 640 kph @ 6700m. 1475/1310 PS (static)
max. cruise. 480 kph @ SL, 585 kph at rated alt (ca 6 km), 1075 / 1080 PS

G-14/U4 (605AM w. MW boost)

568 kph @ SL, 665 kph @ 5000m. 1740/1700 PS (dynamic), datasheet, impossible to make out wheter calculation or test flight
max. cruise. 468 kph @ SL, 590 kph at rated alt (6 km), 1000 / 1080 PS (dynamic)

G-5/AS G-6/AS (605AS) - flight trials at 30 min rating:
507 kph @ SL, 654 kph @ 8300m. 1275/1150 PS (static)*

* at 30 min ratings

G-6/AS (605ASM w. MW boost)
560 kph @ SL, 675 kph @ 7500m. 1800/1500 PS (static), test flight
560 kph @ SL, 690 kph @ 6800m. 1800/1500 PS (static), another test flight
max. cruise. 480 kph @ SL, 610 kph at rated alt (8,4 km), 1030 / 1050 PS

G-14/AS (605ASM w. MW boost)
560 kph @ SL, 680 kph @ 7500m. 1740/1495 PS (dynamic), datasheet, impossible to make out wheter calculation or test flight
max. cruise. 460 kph @ SL, 620 kph at rated alt (8,4 km), 1000 / 1040 PS (dynamic)

G-10/U4 (early 605DM w. MW boost)

560 kph @ SL, 690 kph @ 7500m. 1750/1570 PS (dynamic), datasheet, calculation from August? 1944
max. cruise. 465 kph @ SL, 628 kph at rated alt (8,4 km), 1020 / 1030 PS (dynamic)

K-4 (early 605DM w. MW boost)
580 kph @ SL, 710 kph @ 7500m. 1750/1565 PS (dynamic), datasheet, possibly calculation from August 1944
max. cruise. 477 kph @ SL, 645 kph at rated alt (8,4 km), 1020 / 1030 PS (dynamic)

K-4 (605DB and DC w. MW boost)
DB : 595 kph @ SL, 710 kph @ 7500m. 1850/1600 PS (static), calculation from January 1945
DC : 607 kph @ SL, 710 kph @ 6000m, 710 kph @ 7500m.. 2000/1800/ca. 1600 PS (static), calculation from January 1945

max. cruise. probably the same or a bit better (DB/DC max. cruise power 1100/1140 PS).

Hope this helps.

[Juha]

Hello Kurfürst
IMHO not very similar, only fairly similar, after all G-6 had an engine with more internal volume and more draggy airframe. And in the situation Kurtl described ie enemy fighters around, pilots probably would have used higher power and speed than which gave 315km/h even if 109 had very good acceleration. IMHO at least Dauersparleistung 1,05 ata 890 PS at 5700m giving probably around 500km/h TAS and consumpting 250L/h.

Juha

[Kurfürst]

Well that's as good as it gets as far as data go, because I don't know of any similiar German range table for the G or K series. However datasheets give almost exactly the same max. ranges for G and F as about 600/1000 miles w. or w/o a droptank. Some British G datasheet give as high as 1200 miles.

As a matter of fact, the mid-1942 on the Zeugmeister notes the F-4's range as 1600 km, and the early G-series as 'vorausichtig(sp?) besser' (foreseen to be better).

Re: DB 605A vs 601E the former was an improved version of the latter, and the 605A had better fuel effiency (greater CR and other improvements). For example the 605A at max. cruise seem to develop about 50 HP more with the same amount of fuel used. You are of course right about the increased drag of the airframe, I guess the better engine just evened that out.

Other than, feel free to play with any condition, combination and power setting you deem realistic, that's why I gave the link to the table.

BTW it would also be interesting to know how long Lightning could last over an enemy airbase and still return, preferably while disengaging at high speed.

[Jukka Juutinen]

Kurfürst, how far would the P-38 base be?