Author Topic: AH's Bf109G-2's level top speeds tested. (Read 432 times)

Wmaker · « **on:** May 22, 2002, 11:27:44 AM »

Now that film viewer's digital speed read out has made speed testing accurate I wanted to compare AH's G-2's top speeds at various altitudes to published finnish flight test data.

My test was done offline with no wind layers. War time finnish G-2's had their WEP deactivated totally because of its strain on the engine which were on short supply for finns. So my test was done with "climb and combat power" which means 100% throttle and no WEP in AH.

Here are the results:

Altitude, Flight test speed, AH speed,

0m 325mph 320mph

1000m 340mph 337mph

2000m 357mph 356mph

3000m 366mph 365mph

4000m 370mph 373mph

5000m 379mph 380mph

6000m 397mph 388mph

Except the small variation in the sea level and 6000m speeds AH's speeds match the flight test beautifully!

WTG HTC!!!

LLv34_Camouflage · « **Reply #1 on:** May 22, 2002, 11:46:46 AM »

Good work wmaker! Where did you get the data from?

Here are the speed and climb rate graphs that I drew into the AH graphs, based on the info from Lentajan Nakokulma 2.

Would you like to test the climb rate too?

LLv34_Camouflage · « **Reply #2 on:** May 22, 2002, 11:50:12 AM »

As you can see, the speed graph looks really good. But if the AH G-2's climb rate follows the published AH graph, then it seems that the climb rate is too low. Even without WEP, the FAF G-2 climbed better than the AH G-2 with WEP.

This said, the climb rate should be tested in the game without making any hasty conclusions.

Camo

fats · « **Reply #3 on:** May 22, 2002, 12:41:21 PM »

I recall Lentajan Nakokulma 2 mentions something about non-recommended climb speed used because the way the cooler flaps worked? Maybe it wasn't that book but some other finnish publication, anyway it apparently gave better 'climb performance' than the factory recommended speed. And by better I have no idea what it meant. Now that I try to really think about it all I can remember I saw a test or a pilot saying that non-stantard speed was actually somehow better.

Yeah prolly totally irrelevant.

// fats

funkedup · « **Reply #4 on:** May 22, 2002, 12:43:56 PM »

Camo, I'm not sure how one could look at your graphs and conclude that speed in AH is OK but climb is too low. Looks to me like speed is a little high and climb is a little low. Maybe I am confusing which curve is AH and which is real world?

gatt · « **Reply #5 on:** May 22, 2002, 01:22:41 PM »

Wmaker, I'm not sure that AH's 109G-2 without WEP is like the real DB605A engined G-2 with settings limited at 2,600rpm and 1,3ATA (maximum emergency power allowed by Daimler-Benz till mid-late '43).

From mid -late '43 on, the DB605 engined G-2, G-4 and G-6 were allowed full power (2,800rpm and 1,42ATA that is) by Daimler-Benz (D.Luft.T.2109 G-2, Flugzueg Handbuch, August-Oktober 1943).

Wmaker · « **Reply #6 on:** May 22, 2002, 05:39:48 PM »

Quote

Originally posted by LLv34_Camouflage
Good work wmaker! Where did you get the data from?

Here are the speed and climb rate graphs that I drew into the AH graphs, based on the info from Lentajan Nakokulma 2.

Would you like to test the climb rate too?

That data is from Pekka Kokko's flight test, so it's same data as in Lentäjän Näkökulma II. I got the exact figures on altitudes between 0-6000m from Osprey's "Finnish Aces of World War 2" which refers to that test also.

I realize that AH's G-2 has higher non-WEP speed than 388mph...it just achieves it higher than MT-215 did.

Climb test would be much more difficult one since the fastest way to get altitude in real life may not be the fastest way in AH. IMO it would require many separate climb tests and the best result would be taken into account.

BTW, interesting graphs Camo!! I haven't seen them before, or did you just made them?

Quote

Originally posted by fats
I recall Lentajan Nakokulma 2 mentions something about non-recommended climb speed used because the way the cooler flaps worked? Maybe it wasn't that book but some other finnish publication, anyway it apparently gave better 'climb performance' than the factory recommended speed. And by better I have no idea what it meant. Now that I try to really think about it all I can remember I saw a test or a pilot saying that non-stantard speed was actually somehow better.

Yeah prolly totally irrelevant.

You are right on the money here fats. This indeed is in Lentäjän Näkökulma II. The recomended climb speed is 270km/h Kokko climbed at 300km/h to keep those cooling flaps as little open as possible (they work with thermostat which opens/closes them according to the temperature of cooling liquid. More speed, more airflow to the liquid...the cooler it stays, ...ect ). The difference between 270km/h and 300km/h was only 1m/s though.

Quote

Originally posted by gatt
Wmaker, I'm not sure that AH's 109G-2 without WEP is like the real DB605A engined G-2 with settings limited at 2,600rpm and 1,3ATA (maximum emergency power allowed by Daimler-Benz till mid-late '43).

Neither am I.

I just assumed because 1.3 ata is the highest non-WEP boost pressure in real G-2. And from the numbers I got I think it is.

Quote

Originally posted by gatt
From mid -late '43 on, the DB605 engined G-2, G-4 and G-6 were allowed full power (2,800rpm and 1,42ATA that is) by Daimler-Benz (D.Luft.T.2109 G-2, Flugzueg Handbuch, August-Oktober 1943).

You mean full power as in "climb and combat power" or as in WEP?

AFAIK 1.3 ata (1310hp) is "climb and combat power" and 1.42 ata is "emergency power".

Wmaker · « **Reply #7 on:** May 22, 2002, 05:58:43 PM »

Quote

Originally posted by funkedup
Camo, I'm not sure how one could look at your graphs and conclude that speed in AH is OK but climb is too low. Looks to me like speed is a little high and climb is a little low. Maybe I am confusing which curve is AH and which is real world?

I think Camo took those speeds straight out of the chart (it's a small chart). According to the speeds from "Finnish Aces of World War 2" that "curve" in the middle of the blue line should be somewhat straight line. Correct me if I'm wrong Camo.

EDIT/checked that chart from Lentäjän Näkökulma II...now I think I know where that curve is coming from (You took couple reference points and drew the curve based on them?)./EDIT

What comes to the climb. Red line in AH's chart is climb speed with WEP on (1.42ata, 2800rpm, 1475hp). That blue line is flown with "climb and combat power" only (1.3ata, 2600rpm, 1310hp). But as Camo said, it should be somehow tested in game first.

gatt · « **Reply #8 on:** May 23, 2002, 01:52:17 AM »

I mean the maximum power settings available for the DB605A, the so called "Start-und Notleistung" (output of 1,475ps at 0mt) and not the "Steig und Kampfleistung" (output of 1,310ps at 0mt). The Daimler-Benz manuals usually allow a maximum of 1 minute at those settings. Probably is not our WEP, since we have WEP for about 5 minutes

While the latter settings were usually allowed for about 30 minutes.

P.S.: sorry for the , I had to check tech infos at home.

LLv34_Camouflage · « **Reply #9 on:** May 23, 2002, 12:33:14 PM »

Quote

Originally posted by funkedup
Camo, I'm not sure how one could look at your graphs and conclude that speed in AH is OK but climb is too low. Looks to me like speed is a little high and climb is a little low. Maybe I am confusing which curve is AH and which is real world?

The blue is "real world". The speed is really close, thats why I said its ok. Its within a couple of mph... WM's test confirms this. But the climb rate seems to be out of whack - the AH G2 doesnt climb fast enough. But like I said, this needs to be tested in the game, my speculations are based only on these graphs!

Could someone please test the climb rates using 300 km/h (186 mph, punch it in autopilot) speed, and recording the climb rate readings (from the climb rate gauge) at every 2000ft alt or so? Maybe use 270 km/h (168 mph) as well? It would also be good to record the "time to altitude" with a stop watch. I would do the tests, but I don't have AH here... :/

Yes WM, I made them like you guessed, taking the points from the graph. Accurate enough.

I'll "reverse engineer" the AH graphs as well and put them into an excel sheet. I'll post it here when I'm done!

As far as I know, the max military power that FAF used was 1.3ata, 2600rpm, 1310hp at sea level.

Camo

funkedup · « **Reply #10 on:** May 23, 2002, 01:51:25 PM »

Camo do you mean that the blue line is for MIL power, so we should compare it to HTC's black line? Did you verify that MP and RPM match between HTC MIL power and the test conditions for the blue line?

LLv34_Camouflage · « **Reply #11 on:** May 23, 2002, 03:11:40 PM »

Quote

Originally posted by funkedup
Camo do you mean that the blue line is for MIL power, so we should compare it to HTC's black line? Did you verify that MP and RPM match between HTC MIL power and the test conditions for the blue line?

Yes, the blue and black line should correspond. The FAF test was run at 1.3ata, 2600rpm, full fuel and ammo. Results converted to standard athmosphere. Should be same than full mil in AH?

Here are the graphs from excel. Sorry for the bad quality. Please test the climb performance of the AH G-2 to verify the results.

Camo

LLv34_Camouflage · « **Reply #12 on:** May 23, 2002, 05:07:38 PM »

Hmmm, I wonder why Wmaker and I have different data for the speed test. I must've made a mistake when checking the book. WM, can you verify the LN2 graph numbers, please?

These are what I used:

alt (m)   speed (km/h)
10000   570
8800   600
8000   610
7800   617
6400   636
6000   617
5000   600
4000   586
2350   578
2000   567
0   521

Camo

gatt · « **Reply #13 on:** May 24, 2002, 01:29:16 AM »

Perhaps it can help:

Wmaker · « **Reply #14 on:** May 24, 2002, 10:50:39 AM »

Camo, I wonder how you've gotten so accurate speeds considering the small size of the LN2 chart? Did you scan it for bigger size and do some editing to it? But yes generally your speeds match the chart...of course pretty hard to say if its 520km/h or 521km/h.

Here are the speeds from "Finnish Aces of World War 2" in km/h.

0m, 523km/h

1000m, 547km/h

2000m, 575km/h (your figure 567km/h)

3000m, 589km/h

4000m, 596km/h

5000m, 610km/h

6000m, 639km/h (your figure 617km/h)

These variations got me thinking that maybe there were two seperate tests with MT-215. Difference in air temperature of the day alone could explain the variation.

...Or the chart in LN2 is somewhat inaccurate...

Speed test in which "Finnish Aces of the World War 2" refers is dated 5th of April 1943.