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A request for the Fokker DVII with DIIIaü engine...


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#121 von_Semmel

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Posted 10 October 2012 - 15:50

Do we have any data on how fast it was?


Plane Pfalz D.XII
Year: 1918
kind of plane: fighter
weight(empty): 720 kg
weight (loaded): 905 kg
Engine: Mercedes D IIIaü (160 PS) Benz Bz III (185 PS) Benz Bz III (185 PS) BMW IIIa (185 PS)
max speed at sea level(I think its sea level no special discription in my book :? ): 180 km/h 195 km/h 195 km/h 200 km/h

max altitude: 5.650 m
range: 375 km[6]
max time of flight: 2:30h
weapons: 2 MG
crew: 1
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#122 hq_Jorri

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Posted 10 October 2012 - 15:57

Sorry, I meant the ROF D.XII with the D.IIIa engine.

Really, 170? Did you remember by heart or do we have it written down somewhere? I can't believe it was really that slow…wow.
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#123 Huetz

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Posted 10 October 2012 - 16:09

Sorry, I meant the ROF D.XII with the D.IIIa engine.

Really, 170? Did you remember by heart or do we have it written down somewhere? I can't believe it was really that slow…wow.

Yeah about 175 IIRC. The ultimate dog so far.
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#124 hq_Jorri

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Posted 10 October 2012 - 16:12

:(
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#125 gavagai

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Posted 10 October 2012 - 16:51

Again, the 165kmh figure for the Pfalz D.IIIa is usually quoted without an altitude, but some sources align it with 10,000ft. But in RoF the Pfalz D.IIIa does 165kmh at seal level and TAS at 10,000ft! It seems like neoqb was puzzled about what to do with the available information and made the dubious choice.

If the 170kmh figure for the D.XII with the D.IIIa engine was also an airspeed at altitude, then its being the target figure for airspeed at sea level would go a long way in explaining its doggishness in RoF.

Engine: Mercedes D IIIaü (160 PS) Benz Bz III (185 PS) Benz Bz III (185 PS) BMW IIIa (185 PS)
max speed at sea level(I think its sea level no special discription in my book :? ): 180 km/h 195 km/h 195 km/h

If it doesn't say sea level then you don't know. The only document I have seen with original German test data did not contain sea level measurements. The tests were conducted at three different altitudes, about 2.8, 3.5, and 4km.
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#126 2Lt_Joch

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Posted 10 October 2012 - 17:56

In NACA #46 which summarises a 1919 German report of tests done on a DVII in the fall of 1918, the speed tests were done at an altitude of 600 meters, presumably calculated over MSL. No mention of type, but based on the date and performance it appears to have been equipped with a D.IIIau. Test aircraft had a weight of 906 kg. Speed test at 1440 R.P.M. recorded average of 178 km/h, apparently TAS.

The climb test also showed an average time of 11 minutes to reach 3 km.

link:

http://naca.central..../naca-tm-46.pdf" onclick="window.open(this.href);return false;">http://naca.central....field.ac.uk/rep … -tm-46.pdf
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#127 Huetz

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Posted 10 October 2012 - 19:06

Just to throw that out there Joch, these NACA files all have a big problem: these tests were (most likely) conducted with worn airframes and wrong fuel so the accuracy is dubious and the problematic thing with these is pretty obvious from the first pages: They make not notice off what condition the a/c was in, vital in my opinion considering what they actually did with the airframe during those tests.

There's also no notes on what airscrew was used during these tests, another important factor regarding top speed.

Don't get me wrong, I am convinced that the data supplied in the report is correct but most likely not representative for an a/c in frontline service.
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#128 gavagai

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Posted 10 October 2012 - 19:44

Yup, there are numerous threads at the aerodrome that describe how the D.IIIau would underperform with the wrong fuel type, especially at low altitude.
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#129 2Lt_Joch

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Posted 10 October 2012 - 21:17

Agreed that most of the NACA test reports are of dubious value since they involve tests of captured equipment.

What makes NACA #46 interesting is that is just an english translation of an original German report of flight tests carried out by the Germans themselves in the fall of 1918 at their own Rechlin airplane experiment division. The tests were carried out to test further improvements to airplanes. It is certain they would have been using the right fuel. It is also likely that it would be testing brand new airplanes, since it was a specialized test facility.

It is not perfect, but it is the closest I have seen to an original German flight test of the D.VII.
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#130 gavagai

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Posted 10 October 2012 - 21:25

It is certain they would have been using the right fuel.

The best fuel type was limited in supply. So, possible, but by no means certain. Read here about fliegerbenzin and flugbenzin and the other complications that arise in these discussions.
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#131 Mogster

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Posted 10 October 2012 - 21:27

Aren't there other inconsistencies, didn't some German flight tests use less than full tanks? "enough fuel for an hour" … that sort of thing.

From now on the devs need to look at each released aircrafts performance relative to other planes in the sim. If more of that had been done early on we wouldn't be having some of these discussions.
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#132 2Lt_Joch

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Posted 10 October 2012 - 21:42

It is certain they would have been using the right fuel.

The best fuel type was limited in supply. So, possible, but by no means certain. Read here about fliegerbenzin and flugbenzin and the other complications that arise in these discussions.

I have read all these threads at the aerodrome, most enlightening, but as you say, no one really knows. Every discussion about whether they used Fliegerbenzin or Flugbenzin and what their properties are are just an educated guess.

The D.IIIau was most likely designed for use with flugbenzin, but no one really knows.
The D.IIIau would most likely run better with Fliegerbenzin, but no one knows if there was enough leftover to fuel the D.IIIau fleet after the D.VIIfs had been fueled.

The tests were probably run just on Flugbenzin, but it looks as though that is probably what they ran on in combat anyway.

The climb tests looks right. The lower figure for the speed test probably comes from the fact that the D.IIIau was not supposed to be run at max throttle below 1,800 meters to prevent detonation.
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#133 gavagai

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Posted 10 October 2012 - 22:11

Aren't there other inconsistencies, didn't some German flight tests use less than full tanks? "enough fuel for an hour" … that sort of thing.

Similar to British Camel tests where the gravity tank wasn't filled. ;)

P.S. Another thing that is important, Joch, is the method of determining the airspeed. Those theodolite tests were a new thing and yielded airspeed measurements that were significantly slower across the board compared to British and French methods. When I am back at my desktop machine I can post the article for you.
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#134 NewGuy_

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Posted 10 October 2012 - 22:28

Yes, I will buy any machine that the ROF team makes, but I will really enjoy this one. When I first started playing, ROF was my first multiplayer flight sim experience. I really liked the Fokker DVII, as it was a very newbie friendly ride, but I hated how the experienced multiplayer guys, using the SPAD XIII, the Nieuport 17 guys, and later, the SE5a, could walk all over the Fokker DVII, most of the time. I always thought to myself, this just can't be right! I am not an air ace, but I am in a DVII! How can a blankiing N17 own me?! The DVII was a well regarded machine. Introducing the common variant of the DVII will make a lot of ROF'ers happy, and help to create a better overall late war experience, even for the SPAD guys, like me! :S!: MJ
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Something something SPAD. Something something then dive away. 


#135 =Fifi=

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Posted 10 October 2012 - 22:39

even for the SPAD guys, like me!

Are you really!…didn't noticed :mrgreen:
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#136 2Lt_Joch

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Posted 10 October 2012 - 23:40

Aren't there other inconsistencies, didn't some German flight tests use less than full tanks? "enough fuel for an hour" … that sort of thing.

Similar to British Camel tests where the gravity tank wasn't filled. ;)

P.S. Another thing that is important, Joch, is the method of determining the airspeed. Those theodolite tests were a new thing and yielded airspeed measurements that were significantly slower across the board compared to British and French methods. When I am back at my desktop machine I can post the article for you.


please do, I would be interested.
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#137 NewGuy_

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Posted 11 October 2012 - 00:13

even for the SPAD guys, like me!

Are you really!…didn't noticed :mrgreen:

You bet Fifi. I support Central or the Allies getting all of the machines that they want and I will buy any machine the ROF team makes. Vander made a great argument for this DVII variant. A 1917 SPAD XIII facing off against a common DVII variant makes a lot more sense than putting super slow Central planes against the 1917 SPAD XIII or putting the DVIIf and BMW D.XII against the 1917 SPAD XIII. I hope that Central will be very happy with their new ride. Myself, I can't wait to encounter this DVII variant in my SPAD XIII, "Carmilla," while on the Syndicate! :D :S!: MJ
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Something something SPAD. Something something then dive away. 


#138 NewGuy_

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Posted 11 October 2012 - 00:24



I think that Womenfly2 might have posted this on the ROF Forum before, but here it is again.

:S!: MJ
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Something something SPAD. Something something then dive away. 


#139 =Fifi=

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Posted 11 October 2012 - 01:50

Was always wondering if our ROF DVII had the right engine SOUND in game…i have now the answer!
Devs made it quite close to RL! Cool
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#140 NewGuy_

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Posted 11 October 2012 - 02:15

Was always wondering if our ROF DVII had the right engine SOUND in game…i have now the answer!
Devs made it quite close to RL! Cool

Yes, the devs do a great job, in a great many ways, Fifi. Sound is certainly one of them. :S!: MJ
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Something something SPAD. Something something then dive away. 


#141 gavagai

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Posted 11 October 2012 - 02:33

Aren't there other inconsistencies, didn't some German flight tests use less than full tanks? "enough fuel for an hour" … that sort of thing.

Similar to British Camel tests where the gravity tank wasn't filled. ;)

P.S. Another thing that is important, Joch, is the method of determining the airspeed. Those theodolite tests were a new thing and yielded airspeed measurements that were significantly slower across the board compared to British and French methods. When I am back at my desktop machine I can post the article for you.


please do, I would be interested.

Here you go.

I like this passage:
The sole aim of the present papaer is to remedy the complete lack of data from actual flights and to give the order of magnitude of airplane speeds rather than their accurate values. The investigations described above show, however, that the previously assumed horizontal speeds of airplanes are very far from having been attained and have led to quite erroneous views, not only with us but also in other countries. This astonishing fact is due to not having carried out reliable speed measurements above 2000 meters (6560 feet). According to English and French reports their customary measuring methods (with camera obscura, etc.) can only be used up to altitudes of 1500 meters (4900 feet).

In other words, do not trust in the accuracy of the figures you see in the paper, and certainly do not trust in the accuracy of other published figures!
:S!:

Attached Files


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#142 =Fifi=

=Fifi=
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Posted 11 October 2012 - 02:50

Was always wondering if our ROF DVII had the right engine SOUND in game…i have now the answer!
Devs made it quite close to RL! Cool

Yes, the devs do a great job, in a great many ways, Fifi. Sound is certainly one of them. :S!: MJ

Yeah…except for Spad XIII :(
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#143 NewGuy_

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Posted 11 October 2012 - 03:28

Was always wondering if our ROF DVII had the right engine SOUND in game…i have now the answer!
Devs made it quite close to RL! Cool

Yes, the devs do a great job, in a great many ways, Fifi. Sound is certainly one of them. :S!: MJ

Yeah…except for Spad XIII :(

Well, it is the low compression HS 8 Ba version, so when the 1918 high compression versions come along, maybe they will sound more like a 180 HP SPAD VII, a SE5a or better still, a Plymouth Barracuda. :P

:S!: MJ
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Something something SPAD. Something something then dive away. 


#144 thenorm

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Posted 11 October 2012 - 04:22

What about the Albatros series? I always feel like I'm at low RPM flying them because of the engine sound…
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#145 NewGuy_

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Posted 11 October 2012 - 04:37

What about the Albatros series? I always feel like I'm at low RPM flying them because of the engine sound…

Well, the Alby would sound pretty bad a– with the Mercedes D.IIIau. Take up the 200 hp Halby and listen to the sweet sound of that engine!
:D :S!: MJ
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Something something SPAD. Something something then dive away. 


#146 Tandler

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Posted 11 October 2012 - 08:01

http://www.youtube.c...feature=g-all-u" onclick="window.open(this.href);return false;"> … re=g-all-u
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#147 Voidhunger

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Posted 11 October 2012 - 14:06

Sorry guys if this was posted before, but this data is from the aerodrome.

Die deutschen Militar-flugzeuge 1910-1918 by Krooschel and Stutzer :

Fokker D.VII with 180 PS D.IIIau motor

max. speed
see level 185 km/h
1000m - 187 km/h
2000m - 183 km/h

climb to 1000 - 5m 48sec.
to 5000 - 31m 30 sec.

Pfalz D.XII D.IIIau motor

sea level - 180 km/h

climb to 1000 - 2m 30sec.
to 5000 - 30m 42 sec.
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#148 J2_Adam

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Posted 11 October 2012 - 20:00

Sorry guys if this was posted before, but this data is from the aerodrome.

Die deutschen Militar-flugzeuge 1910-1918 by Krooschel and Stutzer :

Fokker D.VII with 180 PS D.IIIau motor

max. speed
see level 185 km/h
1000m - 187 km/h
2000m - 183 km/h

climb to 1000 - 5m 48sec.
to 5000 - 31m 30 sec.

Pfalz D.XII D.IIIau motor

sea level - 180 km/h

climb to 1000 - 2m 30sec.
to 5000 - 30m 42 sec.

Those climb rates seem way off. For the DVII it shows less then 600 ft/min. The D12 shows over 1300 ft/min. Something is out of wack.
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#149 hq_Jorri

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Posted 11 October 2012 - 20:03

Not sure what data comes from where:

Image
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#150 Soilworker

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Posted 11 October 2012 - 20:28

Man that's quite a difference in times to climb to 1000m between store and Mig's test for both versions.
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#151 Huetz

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Posted 11 October 2012 - 20:34

Man that's quite a difference in times to climb to 1000m between store and Mig's test for both versions.

Could that be attributed to the difference in weight and maybe a different airscrew model? I know it's not that great but there has to be a culprit somewhere. The data seems off by quite a large margin.
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#152 Mogster

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Posted 11 October 2012 - 20:35

So the ROF DVII actually climbs better than that documented version? Or is that the UK test data with the wrong fuel/carb fitted?
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#153 hq_Jorri

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Posted 11 October 2012 - 20:37

He ujsed a lot of different sources, I'm not sure how he compiled the data and which part of the data can be contributed to which source.
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#154 gavagai

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Posted 11 October 2012 - 22:00

Right, the D.VII climbed to 1km more slowly than the Cl.2. :roll:

Some of you need to be a little more critical when you look at performance data. ;) The big merit of the data in the document I posted is that all of the aircraft were tested in the same way by the same people. Most of the performance data comparisons we like to make at the forum to not meet that standard.
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#155 2Lt_Joch

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Posted 12 October 2012 - 12:28

Not sure what data comes from where:

Image


The data comes from a variety of sources and closely matches or is slightly better than what little hard data there is. It's probably the best you can expect in a computer game. The D.IIIau's performance will fall somewhere between the D.IIIa and the BMW, probably closer to D.IIIa perfomance at low level with a bigger gap as altitude increases.
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#156 Mogster

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Posted 13 October 2012 - 16:22

One problem is how much extra performance you give the Diiiau with the altitude throttle open below 1000m?

Guesswork?
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#157 Voidhunger

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Posted 13 October 2012 - 17:23

I think that L. von Richthofen said that D.VII with the D.IIIau had same (or very similar) performance in low altitude like the BMW powered Fokker.
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#158 2Lt_Joch

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Posted 15 October 2012 - 15:52

I think that L. von Richthofen said that D.VII with the D.IIIau had same (or very similar) performance in low altitude like the BMW powered Fokker.

Actually LvR was referring to perfomance below 2km as long as the altitude throttle on the BMW was not engaged:

The BMW motor is a great advancement in the design of aircraft motors.* Through increased over compression, larger bore of the cylinders, and a first-class carburetor, (which was designed particularly for higher altitudes), the Bavarian Motor factory has succeeded to manufacture a motor which makes our D airplanes, (fighter aircraft), superior to all types of enemy aircraft at higher altitudes.

Up to 2000 meters, the BMW motor operates insignificantly better than the over-compressed 160 HP Mercedes Motor.* However, as soon as the "over" gas throttle position is given, the performance of the BMW motor is greatly superior to the over-compressed 160 HP Mercedes.* On average, 5000 meters in 17-20 minutes, and 6000 meters in 23-26 minutes, were achieved.

Of the known enemy aircraft, only the 300 Spads and the 160 HP Nieuport (new type) demonstrate such outstanding performance at high altitude.* Both of these aircraft types are rarely observed at the front.

This is reflected in the 1918 flight tests of the Pflaz XII.

What is unknown is whether there was any advantage in advancing the throttle on the D.IIIau past the max low level mark below 1,800 meters. Some have theorized that a pilot could advance the throttle slightly past this mark and maybe get a 10-20 hp boost at low level, although I have not seen evidence that this was done in practice or that it would yield a tangible improvement. Such a procedure would result in futher "leaning" of the mixture which could increase performance, but would also increase the risk of pre-ignition detonation and damage to the engine.
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#159 gavagai

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Posted 15 October 2012 - 15:58

Yes, that is why Imperator said that the D.IIIau engine would make the Fokker D.VII similar to the D.VIIF, but without the altitude throttle. It would still be a respectable scout, just not a stone cold killer.
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#160 Voidhunger

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Posted 15 October 2012 - 17:13

How is it possible, that there is no data from the Adlershof competition?
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