"Truth be told you will not be able to find much if any real world data on 'energy' values wrt WWII aircraft, not in the post war since/definition of 'energy'..

In that it wasn't until just after WWII that a real 'standard' test was defined to measure energy and the change in energy.. "

Not strictly true Ace of Aces. A number of Fan plots (Dog house plots) for a few aircraft in WWII exist. Specifically the 109E3 and Spit I are there.

http://www.spitfireperformance.com/spit109turn.gif

Though I do agree that general EM theory was in its infancy.

Both the RAE and USN produced some of these. The RAE document "Notes on the dogfight" AVIA 6/2366 discusses sustained turn with respect to excess power and graphical depiction of this using using Fan plots.


a 1G Specific excess power (Ps) chart for the 262 exists as well.

To translate the comparison of Ivan's chart:

For ease of use I take the example of point P: TAS = 250 mph, turn at 3g.

Me109 (written on bottom line):

Phi = 71deg
time for 360deg turn = 25.5sec
turn radius = 1480 ft
angle of descent = 5.2deg (= 2000ft/min)

That means that for a 360deg turn at sustained speed the 109 would have lost about 850 ft.

Spit (type? some eye measure here so plus minus a tat):

Phi = 70.6deg
time for 360deg turn = ~26seg (attention: logarithmic scale!)
turn radius = ~1450-1500ft (I would have to measure it but I don't have a printer)
angle of descent = ~0.5deg (= ~ 190 ft/min)

That means that for a 360deg turn at sustained speed the spit would have lost about 80 ft.

This is albeit for 3g turns only. For a TAS of 250 mph a 3g turn is hence most energy preserving for the Spit. It would loose more energy in a tighter turn at this speed.

For 250 mph the 109 optimal turn load energy-wise would be about 2.3g but then it would also have increased its turn radius and increased its turn radius. Its 360deg turn time would then be about 35-38sec (+40% wrt Spit) and its turn radius 2000 ft (+30% wrt Spit).

Obviously the numbers for energy loss seem significantly different. However in a dogfight one usually never pulls a 360deg turn nor constantly at the same load. In a short duration turn the 109 should be able to turn with the Spit w/o loosing too much energy but of course not continuously.

The Spit also should loose energy if the combination velocity-turn load is above the energy-optimal line (the "Angle of Straight Climb" line). If it retains always energy then something is wrong.

No it is still true..

Note I said 'you will not be able to find much if any' which is different than saying 'you will not be able to find any'. Depending on your definition of 'not much' IMHO finding one or two or three tests falls into the catagory of 'not much'.

Bingo

In light of this, I think we can all agree that no changes should be made until we know what the 'values' should be.. Otherwise we are just basing changes on sim pilot 'feelings' which is NOT something I want my flight sim based on

I think we should make use of the data that is there. That is better than just leaving wrong things as they are. Otherwise you will never change much in the sim and then we have a fake FM.

The chances that the existing data is completely wrong is smaller than the chances of just guesswork.

Allways..

But what about the planes for which there is no data?

A little change in weight, horse power, frame (clip wing) etc can have a big effect on these charts!

But lets assume you can agree to some 'calculated' values..

The next big hurtle for the sim pilot is the validation of the values..

This is all for not unless you come up with a standard test..

And even with that you will than find most sim pilots are not up to the tasks that they can get the same results test after test (read repeatable Ala scientific method)

So even if you had all the info/data.. you would still have to contend with the whinny sim pilots that does not know the difference between TAS and IAS but has not problem calling the FM porked

Indeed. +1

I agree. But still a great opportunity to lay this photo out here.

http://i243.photobucket.com/albums/f...y/lebowski.jpg

The fan plots that I have collected over the years though few in number are:

Spitfire1A
BF109E3
Spitfire MKIII Clean (Merlin XX)
Spitfire MKIII with Full Flap (RAE study on Flap and its effects on turn performance)
Blenheim MKIV (RAE report "Notes on the dogfight)
Brewster Buffalo (F2A) with Flap and Clean (Exhaustive USN/NACA study on Flap effects on turn performance)

I am sure there are more out there but its just finding them.

That's pretty subjective. Unless you've got proof or a recording or some other form of hard data it's irresponsible to make claims like this.

if stating one's honest, yet subjective opinion is irresponsible or requires recordings, we should close 100% of the free world's forums, not to speak about newspapers, parliaments etc. LOL! FM is clearly broken, for all planes, so it is pointless to defend it, full stop (unless you have recordings, of course ...:D).