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92 Sqn. Philstyle (QJ-P)
Feb-11-2013, 11:46
Some time ago, I started building a spread sheet with the intention of compiling historical performance statistics from various Clod related aircraft types into a single location. I began with TAS performance, largely sourcign from these two websites:

http://www.spitfireperformance.com/
http://kurfurst.org/


My intention was to capture a the various different source information together so they could all be compared in one location. This is mainly done for my own personal interest.

Anyways, here is a quick graph showing how the sheet could be used. This graphs combines air-speed (TAS) results from 5 separate aircraft tests (3 of them 87 octane spitfires, and 3 of them 109E variants). Within my master sheet I have identified the source for each test and I have also got notes on aircraft take-off weight (if stated in the source) and any other notes of interest such as whether the aircraft had a metal or wooden propeller (in the case of the spits), or whether or not it is obvious what kind of fuel was being used.
1828
What I would like to do is to combine as many test results as I can find on the internet, and in printed sources. This way it would be possible to paint an "average" picture of performance, based on the various test results for any individual type/ sub-type. Other performance indicators such as climb rate, turn rate etc could be added over time too.


I would be interested to know if any other folks might be keen to help me populate this sheet. PM me if interested.
Also, if anyone else has done something similar, please let me know, so I can save on effort.

LG1.Farber
Feb-11-2013, 12:27
I think you choose the most pasionate websites on earth for their chosen aircraft... Proceed with caution!

O and here a link:

http://www.flightsimtesting.com/IL2CliffsOfDover.aspx

92 Sqn. Philstyle (QJ-P)
Feb-12-2013, 04:03
I think you choose the most pasionate websites on earth for their chosen aircraft... Proceed with caution!

Cheers, will do ;)
I'm trying to note the various "oddities" in each dataset too (such as aircraft weights, fuel loads, armament, whether or not sea-level is identified). I figure the more data I can collect, from the most sources possible, the greater the chance I will be able to smooth out any outlier results...

VO101_Kurfurst
Feb-12-2013, 07:18
Cheers, will do ;)
I'm trying to note the various "oddities" in each dataset too (such as aircraft weights, fuel loads, armament, whether or not sea-level is identified).

Differing testing conditions are the most serious problem with these data. Many of the curves, sheets simply do not note the conditions, use different boosts, radiator settings or even engines... making a simple overlaying of the results can extremely misleading. Believe me I tried, its maddening to make sense out of the figures.

92 Sqn. Philstyle (QJ-P)
Feb-12-2013, 08:22
Differing testing conditions are the most serious problem with these data. Many of the curves, sheets simply do not note the conditions, use different boosts, radiator settings or even engines... making a simple overlaying of the results can extremely misleading. Believe me I tried, its maddening to make sense out of the figures.

Hi, yes I'm aware of this.
Where possible, (that is, where available) I'm trying to make a note of these things.
In some cases we know what the take-off weight was, but not what armament/fuel load that was representative of.
In some cases we have to infer the fuel type based on specified boost-pressure (in the case of the RAF aircraft).

In most cases for allied aircraft I am able to identify the engine type and the propeller type, which is quite helpful. For the German test results this is sometimes less easy to identify - particularly when dealing with poor reproductions/ photocopies documents!

All I can do, is note these things and map the overall results. I am hoping that the "spread" or results will give some informative ranges of performance, rather than exact spot data to base conclusions on.

92 Sqn. Philstyle (QJ-P)
Feb-13-2013, 05:29
Progress update:

I've now compiled the results of 7 separate Spitfire data sets, and 3 109 data sets. The results to date are shown on the graph below. I've got a few more 109 data sets to add in the next couple of days. I've tried to keep RAF aircraft in red/orange/pink and the Luftwaffe aircraft in blue/grey.

1875

Some points of interest:
The RAE extrapolation (spitfire) appears to be so significantly above all other data sets, that it's hard to justify it as anything other than an outlier.
109 results appear to fit a quite small window. However, with only 3 sets of data used to date, it's hard to draw any conclusions.

Osprey
Feb-13-2013, 11:05
No Hurricanes? :(

I like the look of the graphs but you need to specify the boost ratings for those measurements. It looks to me like the 'tit' was not pulled on any of them.

92 Sqn. Philstyle (QJ-P)
Feb-13-2013, 11:14
No Hurricanes? :(

Yet.... ;)


I like the look of the graphs but you need to specify the boost ratings for those measurements. It looks to me like the 'tit' was not pulled on any of them.
You're right, this is not consistently known/ identified at this stage. I try to state the boost pressure or fuel where I know it.

All Spit 2's will be on the 100 Octane? Is this a fair assumption? But I cannot ifnd clear indication that the +12 boost was ever applied in these Spit2 test.
The RAE data for the Spit1a specified that it was an extrapolation for 100 Octane (@12lb boost) - but I think the extrapolation looks too generous (and the curve is suspiciously even suggesting that it's a mathematical extrapolation based on only a couple of points of test data, or possibly even based on another set. Until I can find actual test data showing +12lb in action then it's hard to know what to make of that data.
N3171 was at +6lb boost


If I can find definitive information on boost-pressure or fuel used in any case, I will publish it in the graph.
.

Osprey
Feb-16-2013, 06:43
Yet.... ;)


You're right, this is not consistently known/ identified at this stage. I try to state the boost pressure or fuel where I know it.

All Spit 2's will be on the 100 Octane? Is this a fair assumption? But I cannot ifnd clear indication that the +12 boost was ever applied in these Spit2 test.
The RAE data for the Spit1a specified that it was an extrapolation for 100 Octane (@12lb boost) - but I think the extrapolation looks too generous (and the curve is suspiciously even suggesting that it's a mathematical extrapolation based on only a couple of points of test data, or possibly even based on another set. Until I can find actual test data showing +12lb in action then it's hard to know what to make of that data.
N3171 was at +6lb boost


If I can find definitive information on boost-pressure or fuel used in any case, I will publish it in the graph.
.

Well the trouble is you won't find that because higher boost pressures were for a limited time. This is why you have an added line on one of the spitfire perf . com tests drawn later. There were figures for 12lbs on the deck and that was used to calculate speed to full throttle height AFAIK (312mph). In a nutshell the Spit II had the Merlin XII engine which was designed for 100 octane and could sustain 9lbs with an extra 3lbs by pushing past a dog leg in the throttle control. This was designed for 12lbs below 1000ft but the argument/logic is that pilots in fear of their lives or giving chase would simply use it anyway. The boost pressure would fall from the 9lbs from about 12kft

http://www.spitfireperformance.com/spitfire-II.html

The Spitfire I had the Merlin II and III engines, with the III (mainly) being a mod for a different prop shaft. These had to have a converstion for 100 octane and were rated @ 6.25lbs + up to 12lbs with the tit pulled (could actually achieve 17lbs @ SL if a matchstick was poked into the hole drilled for the mod but it would screw the engine). The speed was about the same as the Spitfire II, but the climb wasn't since the II could achieve an extra 3lbs continuous.

Hope this helps.

LG1.Farber
Feb-16-2013, 11:00
Phil,

Did you see this?

http://forum.il2sturmovik.net/topic/484-soviet-test-of-captured-jg-54-fw-190a-4-video/

Its an interesting thought.

Continu0
Feb-16-2013, 11:28
Phil,

Did you see this?

http://forum.il2sturmovik.net/topic/484-soviet-test-of-captured-jg-54-fw-190a-4-video/

Its an interesting thought.

Also interesting in this video: the dust that comes with the landing at 0.50. Seeing this, CloD doesn`t seem to be that much overdone...

LG1.Farber
Feb-16-2013, 12:12
There are lots of things in sims people want changing to their assumed perspective. Some guy at 1c said the sun was too bright! - I recall (cant remember if I did post or didnt actually) I suggested he might want to go outside and look into the sun to compare it. Anyway, were going off topic.

I thought it was an interesting thought and I guess it shows that each test is different in a 100 ways to the next test and you only really have fragments left to extrapolate data.

92 Sqn. Philstyle (QJ-P)
Feb-16-2013, 12:47
I thought it was an interesting thought and I guess it shows that each test is different in a 100 ways to the next test and you only really have fragments left to extrapolate data.
True.

I'm hoping that by compiling various sets one can at least paint a picture of either the variability, or at least the range of data.
Part of my exercise is to show the folly of relying on a single test to "prove" a point. There will always be ranges of data for historical things, until such time as someone can carry out a full set of modern flight tests of these aircraft with close-to-historical aircraft set-up. Even then, minor variables will influence the results...

LG1.Farber
Feb-16-2013, 18:38
I would search for a similar project... Surely someone has set out on the is task before. It might be interesting especially if you could turn certain data on or off but I think it will never really show anything other than what that data showed in comparison to other data...

As you see already you are coming into problems with different tests of the same aircraft using this seeing or not boost or these settings... plus you have environment conditions, wind, pressure etc and the condition of each aircraft... It really is a mine field.

VO101_Kurfurst
Feb-17-2013, 05:50
I did one quick and dirty complilation a couple of years ago. Have fun deciphering the "facts" from this mess :D