Differences in climb performance Me 109 G

[Achi]

There are great differences in climbperformance refering to the Me 109 G.It range from 16.5 m/sec at groundlevel(Augsburg,22.1.44) to 20.5 m/sec (Finland,5.4.43)at groundlevel,too.Many other datas are dotted between this two cornerpoints,all without the gondola-guns and with 1.3 ata.Differences in weight of about 100 kg cannot explain the great differences in performance(in my opinion).Could anyone explain this?

[Juha]

Hello
some points on the Finnish test, the speed was kept higher than the optimal given in manual during the climb test in order to keep radiator flaps closed as much as possible
The plane, MT-215, wasn't equipped with test-flight instrumentation because of it belonged to a combat unit and was used by that unit between tests. Finns had got only 16 Bf 109s by the time of the tests and so none was given to the test facility. The test pilot visited the base time to time and flew the tests during his visits.

Juha

[Achi]

Thank you Juha for reply,maybe thats the reason.Regards,Achi

[Achi]

Tank you , Juha.Maybe that is the reason.Regards,Achi

[Ernst]

There are great differences in climbperformance refering to the Me 109 G.It range from 16.5 m/sec at groundlevel(Augsburg,22.1.44) to 20.5 m/sec (Finland,5.4.43)at groundlevel,too.Many other datas are dotted between this two cornerpoints,all without the gondola-guns and with 1.3 ata.Differences in weight of about 100 kg cannot explain the great differences in performance(in my opinion).Could anyone explain this?

Please, i would like too see these reports. I think these Finnish reports are on 109 G-2 using a Daimler Benz 601 A engine. Daimler Benz 601 was a previous version fo DB 605 series and G-2 used a lighter airframe than posterior G series, however i think (not certain) DB 601 or G-2 airframe not allowed the use of MW 50. G-6 for example performed poorly than G-2 if no MW 50 installed or engaged, but using MW 50 performance is much better. Extra power may require extra structure reinforcement.

109 G series used different engines types and configurations during its service, you must be more specific. The answer is not quite simple.

[Vincenzo]

Please, i would like too see these reports. I think these Finnish reports are on 109 G-2 using a Daimler Benz 601 A engine. Daimler Benz 601 was a previous version fo DB 605 series and G-2 used a lighter airframe than posterior G series, however i think (not certain) DB 601 or G-2 airframe not allowed the use of MW 50. G-6 for example performed poorly than G-2 if no MW 50 installed or engaged, but using MW 50 performance is much better. Extra power may require extra structure reinforcement.

109 G series used different engines types and configurations during its service, you must be more specific. The answer is not quite simple.

Gustav used DB 605, the DB 601 was used only for test purpose.

[Ernst]

Gustav used DB 605, the DB 601 was used only for test purpose.

Yes, i made a mistake. Thank you for correction. You are right, but my appointments continue valid cause G-2 had lighter airframe and without MW 50 G-6 performed poorly than G-2. Using MW 50 its much better.

[Achi]

Hello,thank you for reply.Ernst,I am refering to the G with only 1.3 ata.In www.Kurfürst >Me 109 G>finish test there is a very good explanation of my question,but I oversee this until yet.Therefor Yuha was right.Regards,Achi

[Kurfürst]

I am fairly certain that the low-level climb rate increase in the Finnish test is due to the relatively closed position of the radiator flaps. At the beginning of the climb (h=~0m) the radiator flaps must have been closed or only very little open.

It is noticable that the climb figures agree very well with those measured by the Germans (ie. Rechlin, Erla figures, or Soviet figures of 14513) above the mentiononed 2500 m altitude. See this illustration:



The German standard of measurment was to assume a constant 220mm opening of radiator flaps, used up to the Volldruckhöhe or FTH, then gradually closing above that altitude, reaching cruising position of 50 mm width at the ceiling.

The report states:

Notes of pilot:

At 2500m coolant radiator flaps open fully for the first time.
After that varying between open and closed position.
Above 5500m manifold pressure dropping during climb.
Practical ceiling 10 500m.
Climbs were executed with greater than optimal climbing speed,
in order to improve cooling.
Opening of the radiator flaps noticably decreases the rate of climb.


The deviation from the Augsburg 22.1.44 Mtt compilation report - which itself appears to be based almost entirely on the August 1942 measurement of test aircraft 14 026, which apparently had a faulty engine - can be explained by that on one hand they used considerably larger radiator flap opening (350mm) up to the VDH altitude, and probably the poor condition of the aircraft/engine. Though there were no engine bench tests performed on that aircraft, the fast speed VDH was only 6100m (compare with the nominal 7000 m, and though this varied from aircraft to aircraft, the avarage measured by Erla was 6700 m) indicating some defect in the engine or its supercharger.

[VG-33]

Hello Kurfurst,

Nice drawing.
But, where are your soviet curve is taken from?

Regards

[Achi]

Hello Kurfürst,many thanks you for your answer!

[Kurfürst]

@VG 33

Its from a Soviet book detailing Soviet aero industry, the book has many curves of Soviet, LL and LW aircraft.

Depicted are two 109G-2s, one "five pointer" (gondola guns) and a "three pointer" (w/o gondies).

[Achi]

Very intresting,maybe you can show more from this book relating the climbperformance?It seems for me that the Me 109 has on the whole a great speed in climb ,in comparsion with other fighters.For example :Spitfire Vb - 171 mph @1000 ft,Spitfire Vc - 175.5 mph @ 1000ft,Spitfire IX even with Merlin 66 - 176.5 mph @ 2000 ft,P 38 G - 156 mph @ sealevel, P 51 B-15 - 165 mph @ sealevel,FW 190 A5 - 177 mph @sealevel (source :wwiiaircraftperformance).On the other side for the Me 109 F1/2 is 180 mph denoted (Kennblatt für Flugzeugmuster),all TAS.For the Me 109 G 2 I assume 180 mph TAS,too (ASI minus about 6 mph ).I hope this composition was sofar right.Regards,Achi

[Achi]

Make a mistake,for 109 G2 186 mph ASI and therefor about 192 mph TAS.Regards,Achi