Leading Edge Slats on the Me-109

[Robo.]

Originally Posted by Crumpp

So, does the game model a Spitfire without weapons available or one that is fighting??

When you take off in this game, your Spitfire's gun ports are indeed covered.

Now when you know the wing and slats of V2 were the same, would you care to comment on the spin test report I quoted a couple of pages back?

I agree the stall characteristics of the 109 in game are incorrect but I believe you're equally wrong with you claims about 'non-spinnable design' and 'devices'.

[robtek]

You can even get a C152 to spin, but you have to work for it, same with the 109, it seems, you can get it to spin, if you work at it, but it is very difficult to get the spin without forcing the plane to spin.
That is how i read it.

[taildraggernut]

Originally Posted by robtek

You can even get a C152 to spin, but you have to work for it, same with the 109, it seems, you can get it to spin, if you work at it, but it is very difficult to get the spin without forcing the plane to spin.
That is how i read it.

Not quite, what it really means is the 109's behaviour in the stall is relatively forgiving and gives ample opportunity to recover before things get too far out of shape, the fact remains that slats simply delay onset of a stall and not prevent it completely, if you keep pulling back on the stick after the slats have become ineffective then you increase your chances of entering a spin, the severity of which is subjet to debate but likely to be quite easy to deal with, the key point is once you have been forced into recovery technique during a combat turn you have effectively left the engagement and you are vulnerable.

[robtek]

Originally Posted by taildraggernut

Not quite, what it really means is the 109's behaviour in the stall is relatively forgiving and gives ample opportunity to recover before things get too far out of shape, the fact remains that slats simply delay onset of a stall and not prevent it completely, if you keep pulling back on the stick after the slats have become ineffective then you increase your chances of entering a spin, the severity of which is subjet to debate but likely to be quite easy to deal with, the key point is once you have been forced into recovery technique during a combat turn you have effectively left the engagement and you are vulnerable.

If you reduce it to that, the key point is that the 109 is controlable all the time, even in a high speed stall, and its adversaries aren't, which is a great achievement by itself and should be represented in game.

[taildraggernut]

Originally Posted by robtek

If you reduce it to that, the key point is that the 109 is controlable all the time, even in a high speed stall, and its adversaries aren't, which is a great achievement by itself and should be represented in game.

I'm not sure why you get that impression of it's adversaries, the NACA report on the MkV (which was the worst Spit in terms of stability) was actually quite good, the 109 is not in control all the time, if an aircraft is stalled it has technically lost control and the reports show the 109 could stall with an uncomanded wing drop, an uncomanded motion is by definition not in control, what should be represented in the game is something close to reality and that reality is that both 109's and Spits had very desireable stall handling qualities with both aircraft being pretty benign and in the Spitfires case having particularily good stall warning, I might add that if you were to believe Crumpp then the 109 also loses elevator control.

STALLING CHARACTERISTICS IN MANEUVERS


The stall warning posessed by the Spitfire was especially
beneficial in allowing the Pilot to reach maximum
lift coefficient in accelerated maneuvers.Because of the
neutral static stability of this airplane, the pilot obtained
no indication of the lift coefficient from the motion
of the control stick, nevertheless, he was able to
pull rapidly to maximum lift coefficient in a turn without
danger of inadvertent stalling.Figure 17 shows a time history of a 180 ° turn in
which the stall was reached. The stall in accelerated maneuvers
was very similar to that in the gliding condition.
with gun ports closed, the pilot was able to pull the stick far back without losing control or interrupting the
turn. The airplane tended to pitch down when stalled and
to recover by itself if the stick were not pulled back.
It would be possible for a pilot pursuing an enemy in a
turn to bring his sights on him momentarily by pitching
beyond the stall without fear of rolling instability.

with gun ports open, a right roll occurred if more
than about 10°up elevator were applied. This reaction
caused the airplane to roll out of a left run and into a
right turn.

Time histories of these maneuvers are shown
on figures 18 and 19. In spite of the lateral instability
that occurred in turns with gun ports open, the pilot
was able to approach maximum lift coefficient closely because
of the desirable stall warning.

The maximum lift
coefficient reached in turns from level flight with flaps
up was 1.22. The airplane could be flown beyond the stall
at even lower lift coefficients.

This value of maximum lift coefficient is closer to
that reached from stalls in straight flight with power
off than the value renched with power on because the slipstream
effects in high-speed turns are relatively small,
The lower value of the maximum lift coefficient offsets, to
some extent, the benefit gained by the Spitfire from its
low wing loading in making turns of small radius. Good
stall warning characteristics appear to be essentiai on an airplane with neutral static stability. In airplanes
tested previousiy, which had neutral static stability and
poor stall warning, inadvertent stalling in rapid maneuvers
was practically unavoidable, The stalling characteristics
of the Spitfire are therefore its redeeming feature.
It should be desirable, however, to obtain these characteristics
without sacrificing a high value of the maximum
lift coefficient.

CONCLUSIONS


The Supernarine Spitfire airplane possessed stalling
characteristics essentially in compliance with the requirements
for satisfactory stalling characteristics given
in reference 1 These characteristics may be summarized
as follows:

1. Warning of the complete stall was provided by the
occurrence of buffeting that set in at speeds several miles
per hour above the minimum speed and by the rearward movement
that could be made with the stick after the start of
the stall flow breakdown without causing violent motions
of the airplane.

2. Stall recovery could be made by application of
down elevator, although the recovery from a roll was somewhat
slower than has been measured on some previously
tested airiolanes.

3. The airplane exhibited no dangerous ground-looping
tendencies in landing. Tail-first landings could be readily
made without the occurrence of either lateral or directional
instability due to stalling.

The airplane posessed some unusual characteristics
in stalls that are not required in reference 1. The motion
beyond the stall was not violent and an unusual
amount of lateral control was available in many flight
conditions, even when full up elevator was applied. The
good stalling characteristics allowed the airplane to be
pulled rapidly to maximum lift coefficient in accelerated
maneuvers in spite of its neutral static longitudinal
stability.

I am struggling to find an aspect in that report saying the Spitfire should spin wildly out of control

[robtek]

As usual the answer is only refering with evidence that is supporting the posters opinion and hair-splitting.
1. Did the 109 recover from a high speedstall with only minimal control input? The RAE report says so. Hardly a uncontrolled flight situation then, i'd say.
2. Did the early Spitfire depart from controlled flight in a high speed stall with a flip over and a following spin? Afaik all sides so far have admitted that.

There is no dispute that the controlled stall in the Spitfire was not hard to manage, but then, that was not asked for.

[taildraggernut]

Originally Posted by robtek

As usual the answer is only refering with evidence that is supporting the posters opinion and hair-splitting.
1. Did the 109 recover from a high speedstall with only minimal control input? The RAE report says so. Hardly a uncontrolled flight situation then, i'd say.
2. Did the early Spitfire depart from controlled flight in a high speed stall with a flip over and a following spin? Afaik all sides so far have admitted that.

There is no dispute that the controlled stall in the Spitfire was not hard to manage, but then, that was not asked for.

Please, can I respectfully ask that you don't descend into this mad poo flinging fest that arises every time someone simply has a different oppinion and shows evidence to back up why they have that oppinion.

I merely reminded of the good qualities of the Spitfire handling after you had basically claimed otherwise..

Originally Posted by robtek

If you reduce it to that, the key point is that the 109 is controlable all the time, even in a high speed stall, and its adversaries aren't, which is a great achievement by itself and should be represented in game.

1. Did the 109 recover from a high speedstall with only minimal control input? The RAE report says so. Hardly a uncontrolled flight situation then, i'd say.

Both the 109 and Spitfire had this quality.

2. Did the early Spitfire depart from controlled flight in a high speed stall with a flip over and a following spin? Afaik all sides so far have admitted that.

I don't admit to this, as far as I'm concrned the MkV was the worst Spitfire for longitudinal stability, earlier Spits by default will have had better qualities.

[*Buzzsaw*]

Originally Posted by robtek

As usual the answer is only refering with evidence that is supporting the posters opinion and hair-splitting.
1. Did the 109 recover from a high speedstall with only minimal control input? The RAE report says so. Hardly a uncontrolled flight situation then, i'd say.
2. Did the early Spitfire depart from controlled flight in a high speed stall with a flip over and a following spin? Afaik all sides so far have admitted that.

There is no dispute that the controlled stall in the Spitfire was not hard to manage, but then, that was not asked for.

As has been mentioned several times on this board, the Spitfire's stall was very easy to read and anticipate. Even rookie pilots were capable of learning this, and even in a high speed situation:

From FIRST LIGHT, by Geoffrey Wellum

"I start to black out. Must be pulling 6 G's. Lean forward, raise my feet on to the rudder pedal extensions; God, they're heavy.
The Spit judders, a high speed stall. You can hold a Spitfire on this judder if you're good. Hold on, Geoff! Hold onto this turn. Fly her like hell.

I reckon I'm just a little above, just a fraction, and therefore gaining.

The German pilot is trying to tighten his turn still more to keep up with me and I'm sure I see the 109 flick. I can see the shape of his head quite clearly and even the dark shape of his oxygen mask. Yet again, I imagine that the 109 gives a distinct flick, on the point of a high speed stall. He has to ease his turn a fraction. The Spitfire gains slowly.

I can quote quite a number of other examples.

The Spitfire's 'judder' or shudder or buffet happened before the stall, and it was quite possible to ride this edge for maximum turn rate.

Only those who were ham-handed or completely inexperienced would not know how to use this indicator.

Yes, if pushed beyond this, the Spitfire would flick over on its back and spin, but given the fact its stall speed was lower than the 109's, and it turn circumference was smaller, there was no need to for a pilot to take it that far.

Notice also in this description the 109 'flick' referred to. This is mentioned in many combat accounts, and tells us clearly that in an accelerated stall condition, there was the potential for a wing drop on the 109 if the stall indications are ignored and controls continue to be over-applied.

[Crumpp]

Taildraggernut says:

I am struggling to find an aspect in that report saying the Spitfire should spin wildly out of control

From the Spitfire Mk II Operating Handbook. The same warning appears in all early mark Spitfires:



Roll instability near the stall as noted the NACA agrees with the Operating Note warnings:



That help?

[*Buzzsaw*]

Thanks for providing that documentation to bolster my comments.

Originally Posted by Crumpp

Roll instability near the stall as noted the NACA agrees with the Operating Note warnings:

"The Spitfire possessed GOOD stall warning in the form of buffeting....
...the stick could be moved well back before lateral instability occurred"

"...rolling instability was noted AFTER an unmistakeable warning in the form of buffeting occurred."

Of course the Spitfire's capability of entering a spin off a high speed stall has nothing to do with the 109's slats.

However, I guess this thread has established two things which are incorrectly modelled in the game:

1) The 109's tendency to enter spins easily and the tendency for recovery from spins to be difficult.

2) The lack of modelling of the Spitfire's pre-stall buffeting.

The game Spitfire will clearly enter a spin out of a high speed stall through the path of a flick onto its back.