Spit/109 sea level speed comparisons in 1.08 beta patch

[Osprey]

Originally Posted by Kurfürst

How much excess thrust does a Spitfire at SL, running at +12 boost has at about 280 mph 1g at David?
How much more excess thrust does a Spitfire at SL, running at +12 boost require in 2g turn at about 280 mph David?

I edited it to suit reality, otherwise you may as well have put down 1ata or something equally 'not full power'.

[MiG-3U]

Originally Posted by Kurfürst

Wrong on all accounts.

These are just facts.

Originally Posted by Kurfürst

And with the specs laid down within being guaranteed within +/- 5% by the manufacturer of the product.

Manufacturer's quaranteed performance is not a test data and not relevent.

You were asked real test data for 500kmh and none has been posted.

Originally Posted by Kurfürst

Really. And what power, what supercharger settings, what airframe conditions?

Not specified but these are real tests of the real series planes.

Still, these match well with 109F speed 495kmh for 1.3ata, 500 kmh for 109E at same power or at 1.35ata is unlogical.

Originally Posted by Kurfürst

Speculation.

Yes in small degree, but much less speculation than assume series engine like you do.

Originally Posted by Kurfürst

Look at the source files - or the fact that we a 5-min boost pressure of 1.35 ata...

Hm... in game test data is showing 475kmh which is actually slightly faster than swiss tests but acceptable.

Good work 1C, you are able to see behind speculations.

Edit: The point is that if you put doubt on various data on Spitfire at +12lbs, as you did, you should be just as critical in the case of the 109 data. Otherwise a reader gets impression of double standards.

No anykind of polemics, sarcasm, arrogance nor all those little annoyances intended. Leaving this discussion for next 5 days.

[JtD]

Originally Posted by Kurfürst

Because?

It's in the physics. If you look (very closely in well hidden places) at the turn calc spreadsheet I attached the other day, you can see that near each planes top speed, the 109 gains ~1.1 °/s turn rate for every m/s of speed given up, while the Spitfire gains about ~1.5 °/s turn rate for every m/s given up. This means in example, for a 9°/s turn rate the 109 loses ~29 km/h, while the Spitfire loses ~22 km/h and has thus narrowed the gap by ~7 km/h. It's a trend that continues until at low speeds the Spitfire becomes superior.

---

And can we all, now that we have a chance for few days of peace, just once try to get along with each other in a civilised way? No polemics, arrogance, sarcasm and all these little annoyances for say the next 5 days?

[Glider]

Originally Posted by Robo.

Oh yes, 109 could indeed turn tighter than a Spitfire at speeds around and above 400 kph.

Are you aware of anything apart from a theory that agrees with this?

In reality this was not very relevant in pure horizontal turnfight for the reasons you named. It was great advantage at BnZ maneuvring, even turning with a Spitfire that is breaking away from your attack - you can turn long enough to score nice deflection shot on him.

No you cannot, if a higher speed is such an advantage in a turn then turning when bounced would be an almost suicidal tactic. Yet it was that ability to turn that saved so many pilots. It was the one advantage that Spit V pilots had over the Fw190 and was emphasised at every plot briefing.

But that is not anywhere close to sustained turn, you do a a 1/8 of a turn and away you break. If you stayed at that turn, you would burn your E and you would end up with a very angry Spitfire on your tail very soon.

That would sum up the best tactic for Luftwaffe Pilots fight in the vertical and only do minor, brief turns to get a better shot. Try to turn it into a turning fight and the 109 loses.

[Glider]

Originally Posted by Kurfürst

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?

Interesting that you keep talking about the 6 1/4 boost and not the 12 boost.

How much excess thrust does a Bf 109E at SL running at 1.35ata bppst has at about 280 mph 1g at David?

less than a 12 boost Spitfire

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

Spit every time.
Show any acual test that says otherwise. Show any 262 pilot who says that he would turn faster than any piston fighter.
No, their advantage was speed and the key was keeping your speed high and making it almost impossible to get a shot at you

I am still trying to work out how the German test authorities got it so wrong. I admit that I cannot find any reason and neither can anyone else, so maybe, just maybe they got it right and the 109 couldn't turn inside the Spitfire, after all thats what their official report says

[Igo kyu]

The Falcon (one) manual told us some things that some seem to have forgotten, if they ever read them at all.

Two aircraft at the same speed pulling the same 'g' force, turn the same radius circle.

The same 'g' force at higher speed means an increased radius of turn, and a lower rate of turn.

At the same speed, a higher 'g' force causes a reduced turn radius and increased rate of turn.

This is why a fighter at .98 mach pulling 8 'g' can outturn a missile at 3.0 mach pulling 30 'g', the fighter's rate of turn is higher.

[ATAG_Snapper]

Which explains quite tidily why a Spitfire 1a never fell to a guided air-to-air missile throughout the entire Battle of Britain......

[Bounder!]

Originally Posted by Igo kyu

The Falcon (one) manual told us some things that some seem to have forgotten, if they ever read them at all.

Two aircraft at the same speed pulling the same 'g' force, turn the same radius circle.

The same 'g' force at higher speed means an increased radius of turn, and a lower rate of turn.

At the same speed, a higher 'g' force causes a reduced turn radius and increased rate of turn.

This is why a fighter at .98 mach pulling 8 'g' can outturn a missile at 3.0 mach pulling 30 'g', the fighter's rate of turn is higher.

I'm a little out of my depth here but... I read somewhere that if speed and 'g' are equal then the turning circle is proportional to the wing loading and that is one of the reasons the spit out turns the 109.

[Igo kyu]

Originally Posted by Bounder!

I'm a little out of my depth here but... I read somewhere that if speed and 'g' are equal then the turning circle is proportional to the wing loading and that is one of the reasons the spit out turns the 109.

If speed and 'g' are equal, then the circle must be the same size.

If a spit and a 109 are at the same speed, then the spit can pull more 'g' because the wing of the spit is bigger, and thus the loading (aircraft weight/wing area) is lower, and pulling more 'g' makes the circle smaller. This may fail as a rule when you get up to speeds where enough 'g' can be pulled to break the airframe, or to black out the pilot, but as I understand it these aircraft would have to be diving to get fast enough to break their airframes. It also doesn't apply below stalling speed.

<edit>

Wing loading isn't all the story, the Hurricane's wing was more heavily loaded than the Spitfire's, and the Hurricane turned better/pulled more 'g' at a given speed. The greater thickness of the Hurricane's wing I think had something to do with that.

[IvanK]

Firstly if you think WWII fighter pilots were going to engage in modern energy theory concepts such as sustained optimum energy speed turn fights you are deluding yourselves. Concepts of Energy bleed Ps rates where not really in the the WWII fighter pilots thought process. Zoom and Boom or general turn fighting was. A spitfire pilots mindset was "I can outturn this 109'. The 109 pilots mindset was "I better be careful and not try to turn with this Spit"

The argument about the (debatable) slightly faster level speed of the 109 over the Spitfire means the 109 must have better sustained turn performance at these speeds is bogus imo. If you accept that for a given flight condition the 109 is faster so therefore has superior energy (Ps) than the Spit so therefore can transform this into turn performance advantage think about this. The superior energy (Ps) is only in 1G flight. As soon as you load the airframe up who has the lesser energy rate loss now ? .... i.e. energy bleed ? Ps at 1G and Ps at say 4G are totally different things ... JTD says it quite clearly and even provides some numbers :

"It's in the physics. If you look (very closely in well hidden places) at the turn calc spreadsheet I attached the other day, you can see that near each planes top speed, the 109 gains ~1.1 °/s turn rate for every m/s of speed given up, while the Spitfire gains about ~1.5 °/s turn rate for every m/s given up. This means in example, for a 9°/s turn rate the 109 loses ~29 km/h, while the Spitfire loses ~22 km/h and has thus narrowed the gap by ~7 km/h. It's a trend that continues until at low speeds the Spitfire becomes superior."

So once the G comes on the 109 is losing airspeed faster than the Spit..... and we know where the fight is going now don't we? 1G Ps and Ps under G are not the same thing.

Thats why JTD says (and is correct imo):

"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. "

Then we have this strange concept of the faster 109 being able to turn better than the Spit at say 400Kmh so therefore he can deny a Spit (at less than 400kmh) closing to a Guns shot ! Its an axiom of Defensive BFM that if you just keep turning a slower aircraft can simply arc inside your turn nose in lead and close to guns. Robbo puts it quite eloquently:

"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. "

Kurfurst
"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"....

I'll have a go or comment at least We are talking about 2 aeroplanes one with marginally better 1G Ps at lets say 400kmh. As soon as the 109 starts to turn how much of this Ps superiority does he now have ? If his -Ve Ps under G is less than the Spit then fair enough but is it ? JTD's figure show the 109 -ve Ps under G to be worse than the Spit.

The RAE Fan charts (accepted that a couple of people here contest these) show this quite clearly.