Spit/109 sea level speed comparisons in 1.08 beta patch

[Kurfürst]

Originally Posted by Glider

I do find this theory that the 109 will be able to turn better than a SPit at higher speeds a little foolish.

a) There are no, repeat no tests, from any side that support this theory.
b) The 109 locked up faster than a spitfire at higher speeds so the spit will have all the advantages getting into the turn by which time the 109 will be in the smelly stuff
c) You quickly lose speed in a turn which will nulify any theoretical advantages
d) The above description of what will happen shows the folly of this theory
e) The 12 boost throws the theory out anyway as it passes the power to weight ratio advantage to the SPitfire
f) Its worth remembering what the German test establishment said about the turning ability of these aircraft:-

Before turning fights with the Bf 109 E type, it must be noted in every case, that
all three foreign planes have significantly smaller turning circles and turning times.
An attack on the opponent as well as disengagement can only be accomplished on the basis of
existing superiority in performance.

Notice it doesn't say:-
a) The SPitfire is better at slow speeds
b) That the 109 can turn inside the Spitfire at high speeds
c) Ensure you keep your speed up against the Spitfire in a turning fight

It says basically DON'T GET INTO A TURNING FIGHT.

Can someone explain how the German test establishment got it so wrong.
After all they only had the real aircraft, real pilots to fly mock combats who obviously were very up to date on the Me109, amongst the finest engineers and designers in the world, people both well versed in the theory and experienced in this field, plus the resources of a test establishment.
I repeat the question, how did they get it so wrong?

Just explain how a plane with less or no excess thrust can pull a sustained turn better than a plane with more excess thrust, thank you.

How much excess thrust does a Spitfire at SL, running at +6 1/4 boost has at about 280 mph 1g at David?
How much more excess thrust does a Spitfire at SL, running at +6 1/4 boost require in 2g turn at about 280 mph David?
How much excess thrust does a Bf 109E at SL running at 1.35ata bppst has at about 280 mph 1g at David?

Which has a better sustained turn at 400 mph David, a Spitfire IX or a Me 262 (P-80 if you like)?

[bongodriver]

Originally Posted by Kurfürst

the Spit WILL loose that turn contest.
.

How exactly? the Spit wil still be able to turn at a higher rate of turn but it won't maintain that speed, if it's behind the 109 it will keep it in it's sights and if its ahead the 109 won't get a bead and will just whizz past, you must realize the Spit will have a better 'rate' of turn than the 109 at all speeds.

[JtD]

With a fixed trim at a constant engine power setting, the trim speed of an aircraft is not going to remain constant over altitude. 400 IAS seems to be a pretty high cruising speed at 5 km for a 109E.

[Kurfürst]

Originally Posted by bongodriver

How exactly?

Well let's start with the fact that it turns better already at 400 kph. Everything Spit does, the 109 can do better at these speeds.

the Spit wil still be able to turn at a higher rate of turn but it won't maintain that speed,

That's an unsustained turn. What you forget that in an unsustained turn, the 109 will still loose less speed than the Spit at high speeds, because the basics (=more excess thrust) did not change.

if it's behind the 109 it will keep it in it's sights and if its ahead the 109 won't get a bead and will just whizz past,

If it's behind the 109 and slows down to match the turn the 109 will get out of range quickly and the 109 will be at superior E state.. if the 109 is behind yes the 109 will just wizz past, and at a superior E state. Then cat-and-mouse begins...

you must realize the Spit will have a better 'rate' of turn than the 109 at all speeds.

Simply no. At high speeds it cannot mach the 109 sustained turn, and it will loose more speed in an unsustained turn if the 109 also goes to unsustained turn.

You see the turn rate advantage is only there if the 109 maintains a sustained turn and the Spit goes for an unsustained turn -> superior E for the 109 and you do not want to fight a 109 with

And unfortunately the Spit cannot beat the 109 at high speed in unsustained turns either. The 109 can match an unsustained turn at any time AND loose less speed in the process. If the pilot has his wits about him he will take advantage of this and use the superior E before speed gets really slow where it's Spitfire territory.

The slower Spitfire (at +6) cannot match the faster 109 (any plane) at high speed turns. At least, not for long.

[JtD]

Originally Posted by Kurfürst

That's an unsustained turn. What you forget that in an unsustained turn, the 109 will still loose less speed than the Spit at high speeds, because the basics (=more excess thrust) did not change.

No, this isn't necessarily an unsustained turn. The same way the 109 has to give up level speed to turn, the Spitfire has, and for each change in turn rate, the speed loss of the 109 is higher, or for each loss of speed, the Spitfires turn rate change is larger. If the 109 settles at a load factor or turn rate, the Spitfire can do the same, at a lower speed.

It really sums up to that the 109's biggest advantage is in flying straight and level, it will remain competitive throughout the high & medium speed range, with the advantage always decreasing. All this, mind you, at sea level against a 6.25lb boosted Spitfire I, which is as good as it gets for the 109.

[Osprey]

Originally Posted by bongodriver

there has never been any disagreement that the 109 had better speed to maintain an overall tactical advantage, the 109 could choose when to engage but the Spitfire was more than capable of evading, if you felt frustrated by that as a 109 driver and decided to try for a propper knife-fight with a Spit you were likely to lose, the 109's best tactic was to run in quick when an opportunity presents itself and run away quicker once the job is done.

I assume you are talking about current in game because the Spitfire is not a slower aeroplane, the 109 and Spitfire are very close throughout altitudes.

Whilst I understand Kurfursts point about the Spitfire @+6 the fact of the matter is that it could manage +12 for a significant time. If you are simply setting a scenario where the Spitfire can actually only manage +6 for whatever reason then we could chuck in all sorts, such as the 109 being out of cannon or leaking Glycol, same for the Spitfire. It's either ceteris paribus or a bit pointless to compare imo.

[Robo.]

Originally Posted by Kurfürst

IMHO the real question is how much time to Spit has to shoot at you?

Hi Kurfurst,

of course depending on the situation, I say just long enough to score a kill. That is my experience at least, I fly both 109s and Spitfires and pretty much anything in 1946. We're talking strictly horizontal fight as for pure sustained turn performance comparsion.

The question is also, for how long would you keep 400kph IAS in horizontal turn. I see where you're coming from though, you certainly have a point. Let's say the 109 wants to stay out of Spitfires gun range, in that case even 400kph turn would not be sufficient.

Originally Posted by Kurfürst

Because if the Spit turns at around its peak sustained turn rate - at about 250 kph? 300 max? - its going to be a good deal slower than the 109; maybe slow enough to fall so behind that it will be out of realistic guns range? You cant shoot what is not in range, even if your nose points towards it..

Theoretically, that is absolutely possible. But it is also possible to cut the corner of the 109 and shoot at it alright at lead curve, then ease up the turn and repeat. All depends on the trajectory, the planes will obviously turn on different circles etc. If you make a deal that the 109 won't climb or scissor, just turn, you will win. Because the Spitfire is much better TnB fighter than Emil. Emil is decent turner, too, very maneuvrable and agile, but as for the sustained turn competition in actual dogfight, Spitfire has got better qualities.

Originally Posted by Kurfürst

Moreover if say both aircraft start at 400 + kph, the 109 maintains it while the Spit bleeds it off to get a snapshop, all the 109 has to do is to level out with a very significant E advantage, and if the pilot is good at Energy fight, its all cat-and-mouse from there on.

Of course, but energy fight is not sustained turn fight.

Originally Posted by Kurfürst

Generally it seems to me a good idea to keep the speed over 400 km/h in a 109.

Yes of course, that's a great idea in any aircraft But even having 400kph+, I would not enter turnfight with a Spitfire because that bloody thing turns better and would shoot at me. And I don't like that.

[MiG-3U]

Originally Posted by Kurfürst

Its a gut feeling of course - I wasn't there when it was drawn (thank God for that!). To me it just seems that, given that the original was drawn with pen AND was labeled, compared to the rough approximation visibile on the pencil drawn +12 and +16(?!) lines, the latter lines were probably made by some aircraft enthusiast well after the war. The lines/figures look more or less a reasonable guesswork, but I very much doubt it has anything to do with any test establishment.

Hm... using the same standars there is no real test data supporting 109E doing 500kmh at sea level. Only a calculation based on a prototype aircraft with a non-standard two speed supercharger and a power value which is higher than normal 601 power.

However, there is several test data sets supporting speeds around 470kmh for 1.3ata and supposedly faster 109F is doing just 495kmh at same power according to kenblat.

[Kurfürst]

Originally Posted by MiG-3U

Hm... using the same standars there is no real test data supporting 109E doing 500kmh at sea level.

Of course there it is.

Only a calculation based on a prototype aircraft with a non-standard two speed supercharger and a power value which is higher than normal 601 power.

I call BS on this. Got any sources for these claims?

However, there is several test data sets supporting speeds around 470kmh for 1.3ata and supposedly faster 109F is doing just 495kmh at same power according to kenblat.

I would like to see them. Hopefully, they are just as detailed as the flight tests and official specs you are dismissing. That includes calibration curves for the pitot, boost and speed measured at various altitudes and known conditions, and proof check of the engine at a bench.

[MiG-3U]

Originally Posted by Kurfürst

Of course there it is.

Please post.

Originally Posted by Kurfürst

I call BS on this. Got any sources for these claims?

V15 chart on your site shows clearly two speed supercharger and text sites höhen and bodenlader, power value in the calculation is 1018ps vs 990ps for Db601A.

All at your site including 109F kenblat.