Corsair VS Spitfire

[GregP]

Hi Adler,

I don't use Kurfurst because when I first found the site, I started checking his data and found that he presented only the fastest data he could find. That is, if there were 3 flight tests out there for some variant of the Bf 109, he presented only the fastest, at the time. The time was some 10 years ago. I concluded he had an agenda to enhance the perceived flight performance of the type and removed his site from my list of references to check.

If that has changed, perhaps it is time to add him back in, but only if he presents the facts and not just "selected" facts that show the fastest speeds, climbs, etc. .

In no way does this say his claims are false, just that I think they are incomplete, at a minimum. I have no opinion on it otherwise. All types have their fans.

As an engineer, if I see 3 data points, the reasonable assumption is either the average or perhaps the median, not the slowest or the fastest.

So, I'll say that I have read the Bf 109F was the favorite mount of Erich Hartmann and several other top aces. That says a lot for the aircraft and I like it as a fighter. But I am under the distinct impression that it was out of its element when fast (above 330 mph), was about a 385 - 390 mph aircraft at best altitude, and had a very good climb rate since it was also one of the lighter Bf 109 variants. I'd go so far as to say they could have stopped development with the F and the front-line pilots might have been happy.

But I'd still like to see real flight test data of a combat-ready aircraft selected from a front-line unit, like we see with U.S. and UK fighters. To date, I have not seen it. Doesn't mean it doesn't exist and, if it does, it will surface sometime, and we can all have a much-anticipated look at it. I'm looking forward to that.

 

[Shortround6]

IN the case of the Corsair I believe the speed was recorded or "set" on a flight from the Vought factory in Stratford CT and the P & W plant in East Hartford CT.
However the conditions are not recorded, as in what throttle settings, what altitude, prevailing winds ( the direction of the flight was to the Northeast and the prevailing winds in area are out of the west) and so on. The plane may have been "timed" at 400 + mph between the two airfields ( a distance of about 48 miles) but without any data the 400mph title is pretty meaning less.

Please remember that the Hawker Hurricane set a "record" of 400mph on a flight in Great Britain to the announcement in headlines .
It was "true" but the amount of assist from tailwinds was not reveled and the Hurricane was in no way a 400 mph aircraft.

 

[CORSNING]

I don't use Kurfurst as a reference, but thanks for the links.

Greg,
I personally have found no fault with Kurfurst's site to date.

 

[CORSNING]

Comparing published performance values is silly absent the stated conditions of the test - most importantly gross weight compared to speed run weight; engine RPM/MP; external configuration (racks/no); Combat load versus reduced fuel/ammo; surface prep (taped gun ports, surface finish); etc.

The only speeds worth comparing were the equivalent fully loaded configurations as expected to engage in combat for averages derived at MP or WEP MP settings as approved by respective authorities (AAF Material Command, for example). Anything else is not presenting anywhere near complete information

I mostly agree Bill. And I agree that in 95% or more of the time your statements are
absolutely true. It is however very advantages from a strategic point of view to know
what the aircraft is capable of in a clean (no pylons, shackles or braces) condition.
Operation Crossbow is a typical example.

Bill is correct for the most part, I'm just saying...[/QUOTE]

 

[DerAdlerIstGelandet]

Hi Adler,

I don't use Kurfurst because when I first found the site, I started checking his data and found that he presented only the fastest data he could find. That is, if there were 3 flight tests out there for some variant of the Bf 109, he presented only the fastest, at the time. The time was some 10 years ago. I concluded he had an agenda to enhance the perceived flight performance of the type and removed his site from my list of references to check.

If that has changed, perhaps it is time to add him back in, but only if he presents the facts and not just "selected" facts that show the fastest speeds, climbs, etc. .

In no way does this say his claims are false, just that I think they are incomplete, at a minimum. I have no opinion on it otherwise. All types have their fans.

As an engineer, if I see 3 data points, the reasonable assumption is either the average or perhaps the median, not the slowest or the fastest.

So, I'll say that I have read the Bf 109F was the favorite mount of Erich Hartmann and several other top aces. That says a lot for the aircraft and I like it as a fighter. But I am under the distinct impression that it was out of its element when fast (above 330 mph), was about a 385 - 390 mph aircraft at best altitude, and had a very good climb rate since it was also one of the lighter Bf 109 variants. I'd go so far as to say they could have stopped development with the F and the front-line pilots might have been happy.

But I'd still like to see real flight test data of a combat-ready aircraft selected from a front-line unit, like we see with U.S. and UK fighters. To date, I have not seen it. Doesn't mean it doesn't exist and, if it does, it will surface sometime, and we can all have a much-anticipated look at it. I'm looking forward to that.

So if he presents Luftwaffe Datenblatts, those too are wrong?

 

[Robert Porter]

No, I have heard elsewhere that Kurfurst cherry picks what data he posts. I think that is the issue with him. His data is not incorrect or fraudulent it is incomplete and therefor does not show the whole story.

 

[CORSNING]

Please see the following links at Kurfurst's website on the Bf-109F-4.
Kurfürst - Mtt. AG. Datenblatt, Me 109 G - 1. Ausführung
Kurfürst - Mtt. AG. Datenblatt, Me 109 G - 1. Ausführung
If I read those reports correctly, there was at least 1 F that did 400mph +.
Eagledad

A direct quote from Kurfurst concerning the 660 km/h of the Bf.109F-4:
" It is notic(e)able that while the associated horsepower and level speed
results at Sea Level are practically identical, the two data sets show increasing
separation as altitude increases, considering the aformentioned characteristics
sheets and graphs repetedly claim the 635 km/h (@ 1.30 ata) value at the
same power setting in agreement with the IV/78/42 calculated data sheet,
it seems likely that the flight tested data sheet IV/43/42 is without
compressability correction. The lack of such correction would characteristically
result in increasingly higher instrument reading error with the increase of altitude,
the read error levels peaking out at maximum speed at the rated altitude."

 

[GregP]

Hi Alder,

I have not found wrong data, as I stated on Kursurst. Only the fastest tests out of the bunch. It's not a knock on his website for anyone else in here.

I simply look for the data myself when it comes to the Bf 109. Not suggesting anyone else do the same. It's not significant to the members in here what source I use when looking at the Bf 109, I certainly hope. Mostly, I try to use wwiiaircraftperformance.

 

[DerAdlerIstGelandet]

No, I have heard elsewhere that Kurfurst cherry picks what data he posts. I think that is the issue with him. His data is not incorrect or fraudulent it is incomplete and therefor does not show the whole story.

There is not a site out there that does not do that, whether it be Kurfurst or a Spitfire or P-51 site.

My point is this, throughtout the site actuall documents are presented. Those documents are not cherry picked, as they are factual documents.

 

[DerAdlerIstGelandet]

Hi Alder,

I have not found wrong data, as I stated on Kursurst. Only the fastest tests out of the bunch. It's not a knock on his website for anyone else in here.

I simply look for the data myself when it comes to the Bf 109. Not suggesting anyone else do the same. It's not significant to the members in here what source I use when looking at the Bf 109, I certainly hope. Mostly, I try to use wwiiaircraftperformance.

And my point is still this, in order to obtain factual data one must either use actual documents, or compare sources. Only getting data by cherry picking your sources in the end achieves nothing. Usually the truth lies in between because every site cherry pics its data in one form or another.

 

[GregP]

That's why it is good to get official government tests when possible.

 

[parsifal]

should point out that at least one source ive read, concerning the F6Fs used at Phil sea and nominally rated as 371mph top speed were unable to exceed 359mph they were that clapped out during the actual battle.

Actual combat performance were routinely a lot less than the published figures for all combatants. Same applied for ships. Italian ships often had quoted flank speeds exceeding those of their RN counterparts (generally around 33 knots) , in fact after a couple of years of high wear and tear, and under normal wartime conditions, few Italian ships (DDs in particular) could exceed 28 knots best sea speed. sustained sea speeds were even less.

 

[DerAdlerIstGelandet]

That's why it is good to get official government tests when possible.

And those are readily available all over the place (including his site).

 

[GregP]

The performance in a Pilot's Operating Handbook for something like a Cessna 182 is the performance attained by a factory test pilot, familiar with the aircraft, using a brand new aircraft, on a hard-surface runway (you can bet it is smooth), with a brand new engine making rated power through a brand new, unworn propeller, using best pilot techniques as indicated by prior flight tests.

Fighter manufacturers also employed specialized test pilots to do the same thing. Factory numbers will ALWAYS degrade with time and wear and environmental exposure, even if the plane is kept in a hangar at all time when not flying.

No surprises there.

The surprise is the number of people, usually non-pilots who think combat flight sims on a PC are realistic, who assume older planes, kept outside, will still meet factory-fresh numbers. All service pilots know that is not the case. Many civil aircraft do not degrade nearly as quickly as they don't have much performance to start with, and never get up into higher speed regimes where the finish and dirt/mud combined with worn turbine blades can create a LOT of minor issues adding up to considerable performance degradation. You might not even notice it since most fast military planes hardly ever get up to top speed in peacetime.

 

[Shortround6]

should point out that at least one source ive read, concerning the F6Fs used at Phil sea and nominally rated as 371mph top speed were unable to exceed 359mph they were that clapped out during the actual battle.

Actual combat performance were routinely a lot less than the published figures for all combatants. Same applied for ships. Italian ships often had quoted flank speeds exceeding those of their RN counterparts (generally around 33 knots) , in fact after a couple of years of high wear and tear, and under normal wartime conditions, few Italian ships (DDs in particular) could exceed 28 knots best sea speed. sustained sea speeds were even less.

I believe in some cases the Italian ships ran trials without all the armament installed (missing turrets or gun mounts) let alone leaving the magazines empty and fuel tanks holding only enough fuel to complete the trials. Partial crews and other "tricks".

Other Navies may have used 2/3s full magazines and/or fuel tanks (and feed water) or 1/2 load.

While the Italian figures made good headlines in the News papers I doubt any Italian ship of the period could meet it's trial speed when actually fitted out for service and I am note even talking about full load or wear and tear.

Italian builders were often paid large bonuses for exceeding design speed figures so a lot skulduggery went on.

 

[DerAdlerIstGelandet]

The performance in a Pilot's Operating Handbook for something like a Cessna 182 is the performance attained by a factory test pilot, familiar with the aircraft, using a brand new aircraft, on a hard-surface runway (you can bet it is smooth), with a brand new engine making rated power through a brand new, unworn propeller, using best pilot techniques as indicated by prior flight tests.

Fighter manufacturers also employed specialized test pilots to do the same thing. Factory numbers will ALWAYS degrade with time and wear and environmental exposure, even if the plane is kept in a hangar at all time when not flying.

No surprises there.

The surprise is the number of people, usually non-pilots who think combat flight sims on a PC are realistic, who assume older planes, kept outside, will still meet factory-fresh numbers. All service pilots know that is not the case. Many civil aircraft do not degrade nearly as quickly as they don't have much performance to start with, and never get up into higher speed regimes where the finish and dirt/mud combined with worn turbine blades can create a LOT of minor issues adding up to considerable performance degradation. You might not even notice it since most fast military planes hardly ever get up to top speed in peacetime.

I am well aware of all that Greg...

I've been in aviation (both military and civilian) for 17 years...Maintenance, crewing and pilot.

Edit: My apologies. I think your post was directed at someone else.

 

[parsifal]

There was quite a bit of that performance chicanery in the Italian and French navies, but even so, at the beginning of the war, the performance of Italian ships was generally higher than their British counterparts by about 2-3 knots. but with wartime use and abuse, the Italian ships could not sustain that performance advantage. their ships engines wore out quickly in other words.

 

[Shortround6]

Went with the chicanery, Power plants were probably lighter per hp than British or American power plants. And thus a bit low on durability.
Destroyer machinery is lighter than cruiser machinery, Cruiser machinery is lighter than Capital Ship machinery on a per HP basis. Machinery also includes condensers and "auxiliaries" generators, pumps, and ventilation equipment.
British ships were designed for the long haul, and being able to operate world wide for months on end without dockyard support which means heavier machinery for reliability.

 

[parsifal]

Pretty much agree. British ships happened to be fairly durable, not so much as a deliberate design choice, but then again maybe. It was simply that they were never designed or used really to force the machinery. Performance of British ships was always intended to be fairly modest. There simply was not seen as essential that RN ships be able to outrun their opponents. A british TF would prefer to sit there and fight it out rather than hightail outta there. If, as was shown in the war, they did need to bug out, they would do it on a controlled basis more often than a headlong rush. that kind of philosophy does not demand exceptional performance.

Later as the numbers of ships exploded, both the RN and the USN could afford the time to put ships through proper maintenance periods. If you properly maintain your engines, be they marine, aero or land based, you will retain most of your design performance for longer. for various reasons, the Italians were not able to do that and this surely had an effect on the performance of their ships as they got further into the war.

I would not be surpised to find the germans in a similar predicament for their aircraft. the germans were always less well supplied with engines compared to the allies. One could reasonably expect that the performance n the field of their actual aircraft would fall short of the published figures of that type. and then of course there is their fuel quality issues, a whole other world for discussion.

 

[Shortround6]

The British had gotten over the "forcing" of machinery in trials in the 1890s or at least before WWI. At least some old editions of "Janes" make note of certain ships that were "forced" on their trials and had a long and troublesome career there after. Rarely able to make full speed on annual trials and/or spending more time in dock than sister ships that were not "forced".

Now this could vary from class to class and a certain amount of overload was common. Original design HP for the WW I C & D class cruisers was 30,000hp but they were often run at up to 40,000hp and later were pretty much rated at 40,000hp. However these power plants were considerably heavier than the 40,000hp power plants used in the large destroyer leaders of WW I.

with the Treaties the British never had the number of ships they wanted and needed a higher percentage in service rather than in dockyard hands. A bit less "paper" performance for a bit more reliability at sea was probably seen as a good trade-off.

I am not saying the British were perfect but what running the escorted convoys in WW I they probably had a better idea of "real world" performance than most other navies. The need for high freeboard for one thing. More hull weight in a treaty limited ship.