Bf-109 vs. Spitfire....

[Hop]

Hop you really should learn to read those charts...

The figures on that chart are at Start u. Notleistung, and "Without" MW-50, as-well as at a considerable overweight. Oh and they are at 1.8 ata supercharger pressure. (Notice "Grundeinstellg", and how the top figure at 1.8ata is the best climbing one)

I know. Note that I said the climb rate of the K4 with Mw50 and C3 fuel was close to 25 m/s, this chart shows a maximum close to 22 m/s.

The most interesting thing about this chart is that it's almost certainly the source for the mistaken "3 mins to 3,000m" and "6.7 mins to 10,000m" claims.

Oh, and where did William Green misread that chart ? It says exactly 6.7min to 10k

No it doesn't. You are assuming the m/s scale is also minutes. I assume Green made the same assumption. Most of the people who see this chart do.

The M/S scale is not also minutes. In fact, 1 square on that chart = 2 minutes, so the 5 m/s line is also the 10 minute line. The chart shows time to climb at climb and combat power, 1.45 ata, basic setting 1.98 ata (ie an engine configured to run at up to 1.98 ata, but actually running at 1.45 ata)

I worked this out some time ago, because the times on the time to climb line correspond to the times to climb at 1.45ata, and couldn't possibly correspond to 1 square = 1 minute. However, I've since seen the other charts, including the 1.98 ata one I mentioned earlier, and they actually have a visible minute scale along the bottom. 1 square = 2 minutes.

Look at at the time to climb from 2km to 4km on this chart.

If 1 square = 1 minute, it takes just over 1 minute to climb 2km, a rate of 28.5 m/s. That's very fast at that altitude.

If 1 square = 2 minutes, it takes about 2.3 minutes to climb 2km. That's a rate of about 14 m/s. If you look at the climb chart at 3km (the average height between 2 and 4km) then the climb rate is 14 m/s.

You can do this at any height. Try for example 1km to 5km. It's a straight line on the climb chart, so the average speed will be half way along, at 3km. The climb rate at 3km is 14 m/s. To climb from 1km to 4km should take 285 secs at an average of 14 m/s. That's 4.75 mintues.

Look at the time to climb line. If 1 square = 2 minutes, 1km is reached at a shade over 1 minute, 5 km at just under 6 minutes. In other words, it takes about 4.75 minutes to go from 1km to 5km, if 1 square = 2 mins on that chart.

Whilst this works at any altitude, it's most obvious above 8km. Above 8km, the 109 cannot maintain maximum boost pressure, so increasing allowed boost pressure will make no difference. RPM is already at maximum because max rpm was allowed as a climbing setting above 8000m (see the line joining climb and combat and start and emergency at 8,000m)

If 1 square = 1 min, then it takes about 1.7 minutes to climb from 8 to 10 km. That's an average, at 9km, of over 19 m/s. Try plotting that on the chart, at 9 km. It's so far off the actual climb rate it's clearly nonsense. And remember, increasing allowed manifold pressure will do nothing at this altitude, because the supercharger can't even maintain 1.45 ata, let alone 1.8 or 1.98 ata.

Now, if 1 square = 2 minutes, then it takes about 3.3 minutes to climb from 8km to 10km. That's a rate of about 10m/s at 9km, which is bang on the chart.

Whatever altitude you want to plot, you will see that at 1 square = 2 minutes, the time to climb matches climb and combat power.

Btw, please show us that 1.98ata chart of yours, then I'll tell you what it says, thank you.

It's quite clear what it says. It still only shows climb rate at climb and combat, and gives about 13.5 minutes to 10,000m. But there's no calculation needed to prove it, the extra scale for minutes is clear at the bottom.



I'd rather not post it here, because the chap who paid for it from the archives, and who first posted it on Ubi, has since removed the link. However, as he posted it on a public forum, which anyone can join and read, I have no objection in emailing it to you, if you provide an address. (if you'd rather not give out a real address, create a temporary Hotmail or similar account).

[Soren]

Hop that sounds abit far fetched. (Might change my mind when I see that chart of your's though)

Please consider this before making any assumptions:

Bf-109 G-2
Weight: 3,120 kg
Max engine power: 1,350 hp at 1.32ata.

Power-loading: 2.3 kg/hp

Initial climb rate: 4,724 ft/min

HA-1112-MIL Buchon
Weight: 3,180 kg
Max engine power: 1,610 hp

Power-loading: 1.97 kg/hp

Initial climb rate: 5,580 ft/min (And these are modern measurements)

Bf-109 K-4
Weight: 3,362 kg
Max engine power: 2,000 hp at 1.98ata, or 1,850 hp at 1.8ata

Power-loading: 1.68 - 1.81 kg/hp

Initial climb rate: Atleast 5,800 ft/min at 1.98ata, and 5,500 ft/min at 1.8ata.


By comparison the Spitfire LF IX at +25 lb boost (1,970 hp), has a power-loading of 1.70 kg/hp, and climbs at 5,700 ft/min.

Also can't you just PM me the 1.98ata chart ??

[Hop]

PM sent.

Hop that sounds abit far fetched. (Might change my mind when I see that chart of your's though)

It's actually true, and I'd stake anything on that. I was certain before seeing the chart with a scale on it, even more certain (if such a thing is possible) when I saw the chart with the 1 square = 2 minute scale.

Please consider this before making any assumptions:

Bf-109 G-2
Weight: 3,120 kg
Max engine power: 1,350 hp at 1.32ata.

Power-loading: 2.3 kg/hp

Initial climb rate: 4,724 ft/min

I assume the G2 data comes from the Finnish test?

There are a couple of problems with that. Firstly, it's not clear whether it's corrected for standard atmosphere. In colder conditions, the engine will develop more power, and climb rate will be better.

Secondly, the Finnish pilot reported a higher initial speed, dropping as the climb continued. That gives it partial zoom climb characteristics.

Thirdly, we don't know the radiator settings. Closing the radiator fully made quite a difference to climb rate.

If you look at this graph someone put together, you can see quite clearly how the Finnish G2 figures differ from others, showing an exceptionally high initial spike before falling back:


The other problem with the comparisons is the prop. Props can be optimised for particular speeds. Optimise one for low speed, and you will get good climb rate, but not very good top speed. And of course put in more power than the prop can handle and it's largely wasted.

[lesofprimus]

The bottom line is that everyones test is different, and that chart is as worthless as the sh*t paper I wiped my @ss with an hour ago...

[DerAdlerIstGelandet]

I can completely understand what you are saying. Paper does not make an aircraft.

[Soren]

I just got the chart by Hop, and its one I already have...

It says nothing about 1.98ata, and its still with the experimental propeller, and no weight figures are given. And finally its from 8/4 -1944.

Hop,

Your theory about the Finnish pilot coming in at overspeed just doesn't cut it, cause then the climb rate at SL would've been considerably higher. Besides had the pilot noticed he was coming in too fast for the test, the test would've been aborted and retried, there's no middle ground when it comes to accurately testing the performance envelope of an aircraft. Also if you look at it, it looks kinda like an extension of the Soviet test with the Bf-109G-2/R-6, which would undoubtedly be slower because of its higher weight and drag.

Also please reconsider my last post, cause there's a logic to it all..

[Hop]

I'm a bit disappointed Soren. Earlier on you said this:

Most climb rates floating around in books and on websites today only qoute the 109's climb rate at Start u. Notleistung, while the figures we need are the Sonder Notleistung.

What does the chart I sent show?

Sonder Notleistung

Why ask for a chart showing Sonder Notleistung if you already had it?

And why no mention of the scale? On exactly the same graph type as the first chart, it shows 1 square = 2 mins. Which, together with the fact that at 1 square = 2 mins the first chart shows climb power, rather proves the "3 mins to 5,000m" is a mistake.

If you look at the second chart in conjunction with the first, you find that climb rate went from a peak of just under 22 m/s at 1.8 ata (about 1850ps) to just under 24 m/s at 1.98 ata (about 2000ps). How much difference were you expecting?

Your theory about the Finnish pilot coming in at overspeed just doesn't cut it, cause then the climb rate at SL would've been considerably higher.

Climbing at a higher speed than optimal actually reduces climb rate. See as an example:
http://marinergraphics.com:16080/ww2...109Ftrial5.JPG
(part of Ring's excellent site: http://prodocs.netfirms.com/

It's only if you allow the speed to decrease during the climb that you get a zoom effect. eg, if you start at 250 mph (and there's no suggestion the Finnish test started that high) then allow speed to drop to 200 mph by 5,000ft, in the first 5,000 ft you get not just the energy produced by the engine, but the 50 mph kinetic energy you have given up.

So yes, zoom climb might be a factor in the G2 test. Virtual Pilots have been promising a translation of the text for some time now, if it ever appears we'll know for sure.

But regardless of why the Finnish test has such a high rate at 2,000m, it does have a much higher rate than comaprable tests from the Germans or Russians.

Also please reconsider my last post, cause there's a logic to it all..

The problem I have with you post is that I have now provided 2 original German charts for the 109K4, one at 1.8 ata, one at a higher setting that you refuse to believe is 1.98ata (although there are other charts in the series that explicitly state it is 1.9. You are basing your 109K4 performance claims on tests of earlier 109s, and ignoring the results for the K4.

Are you a member of the AAW forum? I believe it's by invitation only, but if you are a member they had a good discussion on the K4 climb rate there.

If not, Butch (who got the charts from the archives in the first place) posted some on this thread on Ubi:
http://forums.ubi.com/groupee/forums...6071064704/p/9

There's a good follow on discussion where he answers some of your questions. For example:

It says nothing about 1.98ata,

"it's the DB605DC @ 1.98ata with MW-50 Wink for best curves and @ 1.45ata (climb and combat setting) for the worst ones."

and its still with the experimental propeller

"The climb charts for DC605DC and DB605DB show no difference between 12199 and 12199, check for instance the well known climb chart posted here and there. You'll see : "Schrb 12199 u. 12159" written on the second line."

(The "well known chart" is the one I posted in this thread)

and no weight figures are given.

The weight figures are given elsewhere in the report, 3400 kg for the K4.

[Udet]

Gentlemen:

Of course there will be guys willing to debate what DJ_Dalton posted here. We know who they are; two names that come into mind real fast: Jabberwocky and Hop.

But, will their arguments prove DJ_Dalton wrong?

Although I do find the technical scope of the discussion very enlightening and interesting, my main focus has been on the operational record of the planes.

The conclusion has been the same for a good while now: the 109 slammed the Spitfire big time. And apparently, there is nothing in the horizon which might indicate this conclusion could get modified in any manner whatsoever.

Whatever was it that the Spitfire "did better" than any of its contemporary 109s one can only get confused after studying and reading books, articles, lists of claims, watching guncamera footage and speaking with men who fought in the war. The results are crystal clear. I have no problem in letting Spitfire enthusiasts have their candies though.

From the E-3s, E-4s all the way up to the K-4...one can only wonder what the hell was it those "superb" Sptifires were achieving.

In fact, today one can know the "15 minutes of fame" attained by the Spitfire Mk.I during the Battle of Britain (1940) is bogus: there, the venerable Hurricane Mk.I took the brunt of the fight (!).

The world reputation the Sptifre attained right after the BoB, throughout the empire and the rest of the world, was more the result of a good propaganda job and not the outcome of combat against the Luftwaffe. Necessary myths in a nation enduring the kind of situation England did during 1940.

1941, 1942 and the first half of 1943 saw a RAF completely uncapable of achieving anything over the channel and in skies of western europe all by itself, enduring horrific losses in the process. In the meantime, the losses of, say, JG 2 and JG 26 were comfortably within the sustainable range.

(The boldness of most of these guys is nonetheless admirable; they will have a timely explanation for every argument which contests their official history.)

Now, from the second half of 1943 until the end on May 1945? BLESSED BE THE NAME OF THE LORD, for the USA was now assembling in force!!!

1941, it takes guts to even attempt making a case in favour of the Spitfire. Virtually from July to the end of that year, JG 2 and JG 26 ruled the skies over the Channel. Also I have carefully studied the very first months of that same year (1941) of units like JG 3 and I. and IV./JG 51 -before their deployment in the USSR-, which stayed in the west after the BoB. The result is the same. Spitfires uncapable of tangling with the 109s.

Furthermore, two well known battles: the Dieppe Raids and The Channel Dash, what was it the triumphant Spitfires and pilots of the Battle of Britain achieved: Nothing, and they got their butts badly badly kicked.

The reality of battle records! England can you cope? No, you can´t.
Without the massive critical support of both the 8th and 15th AFs, the RAF with all those "super" Spitfires was going nowhere. No swarms of Jugs and Mustangs: no victory against the Luftwaffe.

[Jabberwocky]

Gentlemen:

Of course there will be guys willing to debate what DJ_Dalton posted here. We know who they are; two names that come into mind real fast: Jabberwocky and Hop.

But, will their arguments prove DJ_Dalton wrong?

Although I do find the technical scope of the discussion very enlightening and interesting, my main focus has been on the operational record of the planes.

The conclusion has been the same for a good while now: the 109 slammed the Spitfire big time. And apparently, there is nothing in the horizon which might indicate this conclusion could get modified in any manner whatsoever.

Whatever was it that the Spitfire "did better" than any of its contemporary 109s one can only get confused after studying and reading books, articles, lists of claims, watching guncamera footage and speaking with men who fought in the war. The results are crystal clear. I have no problem in letting Spitfire enthusiasts have their candies though.

From the E-3s, E-4s all the way up to the K-4...one can only wonder what the hell was it those "superb" Sptifires were achieving.

In fact, today one can know the "15 minutes of fame" attained by the Spitfire Mk.I during the Battle of Britain (1940) is bogus: there, the venerable Hurricane Mk.I took the brunt of the fight (!).

The world reputation the Sptifre attained right after the BoB, throughout the empire and the rest of the world, was more the result of a good propaganda job and not the outcome of combat against the Luftwaffe. Necessary myths in a nation enduring the kind of situation England did during 1940.

1941, 1942 and the first half of 1943 saw a RAF completely uncapable of achieving anything over the channel and in skies of western europe all by itself, enduring horrific losses in the process. In the meantime, the losses of, say, JG 2 and JG 26 were comfortably within the sustainable range.

(The boldness of most of these guys is nonetheless admirable; they will have a timely explanation for every argument which contests their official history.)

Now, from the second half of 1943 until the end on May 1945? BLESSED BE THE NAME OF THE LORD, for the USA was now assembling in force!!!

1941, it takes guts to even attempt making a case in favour of the Spitfire. Virtually from July to the end of that year, JG 2 and JG 26 ruled the skies over the Channel. Also I have carefully studied the very first months of that same year (1941) of units like JG 3 and I. and IV./JG 51 -before their deployment in the USSR-, which stayed in the west after the BoB. The result is the same. Spitfires uncapable of tangling with the 109s.

Furthermore, two well known battles: the Dieppe Raids and The Channel Dash, what was it the triumphant Spitfires and pilots of the Battle of Britain achieved: Nothing, and they got their butts badly badly kicked.

The reality of battle records! England can you cope? No, you can´t.
Without the massive critical support of both the 8th and 15th AFs, the RAF with all those "super" Spitfires was going nowhere. No swarms of Jugs and Mustangs: no victory against the Luftwaffe.

Read up on Malta and how outnumbered Spitfire Vc sucessfully fought and beat 109F-4s and 109G-2s

[Dogwalker]

After BOB and until the end of 1943 I think the MTO was the main teater of operations for western fighters.
Even the USAF losses testify that.
Instead looking at the results of single missions, I think North Africa is the best palce to study (if someone want) the prestations of different fighters in combat, since both parts had their numbers of both defensive and offensive missions to do.

[Soren]

Hop,

Firstly I'm the one who's disappointed, cause apparently you don't know the difference between Sonder Notleistung and 1.98ata figures, and apparently you're convinced that running at Start u. Notleistung with 1.8ata means running at 1850 hp - Well sorry Hop, but in that case you need MW-50 applied as-well.(WHICH IT ISN'T IN YOUR PRESENTED CHART !)

However had you presented figures at Sonder Notleistung with 1.8ata, then we could start comparing numbers, but fact is you haven't, only the one you sent to me via PM is at Sonder-Notleistung with 1.8ata. (And I specifically asked for a 1.98ata chart btw)

Secondly the chart you sent me is with a "Dünnblatt schraube 9-12199", which is an experimental propeller. (A propeller designed to sacrifice climb rate for speed)

Thirdly, you somehow magically come to the conclusion that the time to climb indications are double that of the Climb rate indications, now that is not only nonesense cause it would be a waste of paper, but also because that certainly wasn't std. practice - And lastly because then you'd certainly have been notified if that was the case. (Scientists 'also' expect people to be logical)

Look at your Bf-109 G-1 chart from rechlin, how is 'it' set up ?? Yes thats right, both the time to climb 'and' climb rate figures are sharing the same indications for their figures. (Also, just for fun, notice how short the take-off run is, and compare that to the Spit IX.)

And finally the chart you sent me is from 8/4-1944, looong before 1.98ata boost pressure was ever cleared ! Heck its not even with the engine which could achieve 2,000 PS at 1.98ata in the first place ! (Its a D-2 engine!)

[Hop]

but fact is you haven't, only the one you sent to me via PM is at Sonder-Notleistung with 1.8ata. (And I specifically asked for a 1.98ata chart btw)

It actually is a 1.98 chart. That's why the climb performance is about 2 m/s better than the 1.8 ata chart. What do you think accounts for the difference? It can't be weight, or props, or rpm, because the climb rate above critical altitude is the same.

Secondly the chart you sent me is with a "Dünnblatt schraube 9-12199", which is an experimental propeller. (A propeller designed to sacrifice climb rate for speed)

Note that the first chart shows the same climb rate with the 12159 prop.

Thirdly, you somehow magically come to the conclusion that the time to climb indications are double that of the Climb rate indications

No, I come to the conclusion they are exactly the same. The time to climb lines show the time to climb at climb and combat power. Which is rather normal, if you think about it.

The charts show climb rate at climb and combat power, and at start and emergency power. The time to climb line is for climb and combat power.

now that is not only nonesense cause it would be a waste of paper,

Actually the size of the paper is probably the reason for the different scale. If you were to extend the line on that chart to 22 minutes on a scale where 1 square = 1 min, it would be where the text is, leaving no room for the text.

But are you saying you can't read the minutes scale on the chart I sent you? It is very, very clear. There is a "10" under the first "5", a "20" under the "10", and alongside it says: "t [min]"

And lastly because then you'd certainly have been notified if that was the case. (Scientists 'also' expect people to be logical)

What, you mean with a seperate scale along the bottom, like the one that's actually printed there? What do you think the scale is for?

Look at your Bf-109 G-1 chart from rechlin, how is 'it' set up ?? Yes thats right, both the time to climb 'and' climb rate figures are sharing the same indications for their figures.

That's because they're both at climb and combat power. There is no start and emergency power listed, possibly because it was banned on the DB605A for a long time.

And finally the chart you sent me is from 8/4-1944, looong before 1.98ata boost pressure was ever cleared !

I don't think that's the date in the bottom corner. It's part of the report number, also on the page. Can't you see that what you claim is the number 4 is actually 2 Roman numerals? Appears to be IV to me. And the "8" appears to be a symbol rather than a number. The report is labelled A/IV/290/44.

Can I suggest you email Butch and direct these questions to him? He knows a lot more about the 109, especially the K4. If you tell him it's about the chart he posted at Ubi in February, he'll know which one, as he gets asked about it a lot.

[Hop]

Oh, BTW Soren, if you look at the time to climb line on the second chart I sent you, you will see it is exactly the same as on the chart I posted on this thread, and the scale is explicityly labelled as 1 square = 2 mins.

The times to climb are:

5,000m in just under 6 mins
8,000m in almost exactly 10 mins
10,000m in 13.5 minutes
12,000m in about 20.5 minutes

[Soren]

Ok, it seems we’re talking about different charts here, so I’ll try to be abit more specific for you Hop….

1: The chart you sent me “is” from 8/4-1944, it says that quite clearly – 8.IV.1944. Look at other charts, the date is always at the exact same spot, the lower right corner, followed by PET. DB605 chart date

2: The chart is for an engine which isn’t even capable of 1.98ata boost, its a D-2 engine, so it can only be running at 1.8ata.

3: 1.98ata boost pressure was cleared sometime in December 1944, and it was only cleared for the DC engine. And like previously stated, the chart you sent me is not only from 8 months earlier, but also for an entirely different engine ! (And its with a “Dünnblatt” propeller)

4: If you look at the chart you ‘presented’ for the DC/ASC engine, the climb rate is 22m/s at Start u. Notleistung, ‘without’ MW-50 and at 1.8ata.(Which is 1,725 PS btw) Then look at the chart you sent me for the D-2 engine, its 25m/s at Sonder Notleistung ‘with’ MW-50 at 1.8ata.(1,850 PS)

5: Make a guess on how high a climb rate you think the K-4 has with the DB-605DC engine with 2,000 PS@1.98ata, cause considering it has a climb rate of 25m/s with the D-2 engine at 1,850 PS, its atleast going to be around 28m/s. (Up besides the +25lb boost Spit IX, just like the Power-loading suggests)

I hope you get it this time.....

[lesofprimus]

So do I cause its killing my mood........