Its mandatory in the UK for Glider Pilots before they go solo. The test is to enter a full spin at 1,000ft (yes one thousand) from a variety of different scenarios and recover. Trust me at that height you dont see the world go around, just the tree that is in front of you. Its always a B_____ C_____ moment the first time you let a student do it

Getting back to Crumpp's very first posting to start this thread

We also have Crumpp stating:

Ergo: Not one of the aircraft fielded by the Americans during WW2 was designed to Crumpp's set of "standards" - until things were standardised some time after a series of conferences held in October 1944 the American aviation industry was operating to a similar system to that of the British. This whole waste of time argument has been a huge red herring by Crumpp because it is completely irrelevant to anything to do with the design of the Spitfire. :!:

And When did Cooper become a Test Pilot for NACA? 1945! NACA was as dependent on test pilot's opinions as any other nation throughout most of WW2 and probably beyond.

The fact that the Spitfire did not meet some of NACA's criteria, formalised in 1941, should be of no surprise to anyone - I would suggest very few aircraft designed during the late 30s would have met NACA's criteria in full. This thread has been a complete waste of time. :evil:

Who said anything about infinite acceleration?

Did they teach you this in your flight training? I highly doubt it.

Wow, guy....

Only in level flight...

Check out a climb triangle, pilot. A dive is the same as a climb, only difference is how we sum the force vectors.

Weight changes at the sine of the angle.

Sine 90 = 1

When you point the nose straight down (90 degrees), all the weight becomes thrust.

So even though you pull back the throttles on your 2000 hp WWII fighter that weighs 7000 lbs....

Let's see...

Sine 90 * 7000lbs = 7000 lbs of thrust going straight down!

Compare that too:

2000hp*.8np = 1600thp

Thrust @ 150 mph = (1600thp*325)/130.35Kts = 3989.26lbs of thrust.

So you instead of the 4000lbs of thrust available from your engine at full throttle, you have only added almost twice as much at 7000lbs!!


The lift vector is now shifted 90 degrees. The wing still generates lift but it is only opposed by drag. (Weight cosine 90 = ZERO)

The plane will not fly straight down unless held at the zero lift angle of attack. Instead, lift will accelerate it on x-axis or what you know as the Thrust and Drag axis from level flight.

Yes there is induced drag too.


In a verticle dive.

All this is off topic, take it somewhere else.

Start a new thread if you want to understand the forces of flight.

Most fly by wire systems are set up to act as antispin devices. It does happen on accident though. It is generally not recommended for training because of the relaxed stability of most Fly by Wire fighters.

Sort of like the longitudinal instability of the Spitfire...only much more extreme.

Absolutely. It was a requirement for my CFI. Accelerated stalls are back too for Commercial certs. I was glad to see that.

No, it was dependant upon a set of defined standards and measured results.

Pilot opinion was a factor of secondary importance. He was a monkey in the cockpit that operated the measuring equipment and flew the specific profiles.

He did not fly around on a sunny day to report back how wonderful the airplane felt.

:rolleyes:

Only a few narrow minded individuals see this as some attack on their favorite gameshape.

It is the measured and defined flying qualities that make up the "personality" of the airplane.

These characteristics are what make an early Mark Spitfire a unique airplane with its own individual behaviors.

Of course, not all of the airplanes, like the Spitfire, met every requirement. Nobody has claimed anything different. Most were designed before there were any defined standards.

The NACA standards provide a good frame of reference to model these behavior because they measured and defined so many of the WWII aircraft. Most of these airplanes were fixed as a result but many served for long periods of time before their flying qualities were evaluated under a measured and defined system.

That gives us some great information to see those flying qualities added to the game.

Otherwise, it is not much of simulation of a specific airplane if the gameshape does not have the same flying qualities as the airplane it supposed to represent.

This has nothing to do with how well an airplane turns, how fast it goes, climb, or any specific performance. This has to do with how the airplane behaves in achieving that performance.

"Otherwise, it is not much of simulation of a specific airplane if the gameshape does not have the same flying qualities as the airplane it supposed to represent."

Other than quoting reams of academic data this is the very thing you are yet to prove.

You have raised a Bugtracker tracker entry on a subject but have yet to provide any proof to support it that in fact it is a bug in game. You have by your own admission not flown the Sim that much or for example kept up to date with the numerous Beta patches. You opined that gun recoil should be modelled, If you flew the sim you would know that in fact it is.

When you started this thread its purpose was to discuss this issue as it pertained to early mark spitfires IRL, not for a bug tracker entry. It then morphed into this academic treatise that spawned your bug tracker entry. When are you going to actually do some some in game flight testing to actually substantiate your claim that the FM is porked in the Sim ?

What a sad, sad commentary on Crumpp's attitude towards test pilots who often put their lives on the line in all countries. I wonder what Chuck Yeager, Richard Bong or Bill Bridgeman and others would say and do to Crumpp were he to tell them that they were nothing but monkeys in a cockpit operating measuring equipment and flying set profiles...one can only dream! :grin::grin::grin:

Dive to Vne, stomp on the rudder, and pull back as hard as you can.

Fly the airplane in the buffet and time your turn.

Pull back on the stick, release, and note the behavior of the airplane.

Fly at Vmax, pull hard back, hold it at full deflection, and note the behavior.

Fly the airplane trimmed for slow flight, let go of the stick, fire the guns, and note the behavior.

I have played the game and note the behaviors as I play. Just because I don't spend my time making excel spreadsheets does not mean the points are invalid.

:rolleyes:

The job of a Test Pilot as per MIL-Spec Standards...

http://img838.imageshack.us/img838/605/testpilot.jpg

Same as it was under the NACA.

Why don't you read the rest of the statement. The must be some pretty smart monkeys.
Still waiting for analysis of figures 16 17 18 and why 15 isn't an anomaly.

"I have played the game and note the behaviors as I play. Just because I don't spend my time making excel spreadsheets does not mean the points are invalid."

No just your gut feeling not actually measured and or recorded. You post so many charts to support your statements in this thread then jump in the sim and just wing it !

Contrast this with Crumpp's own posting on what was required by his "monkey(s)"...

http://i91.photobucket.com/albums/k3.../testpilot.jpg

Which is also a good description of the test pilot responsible for developing the Spitfire.

Yep, let go of the stick and fire those guns just like real pilots! :grin::grin::grin:

In the end it comes down to the last sentence as underlined here, Mr Mel Gough NACA :

http://i40.photobucket.com/albums/e2...ntftrconf1.jpg
Report of joint Fighter Conference NAS Patuxent River, MD 16-23 Oct 1944.


And the end user of the Spitfire the combat fighter pilot was very happy !

Nobody's saying the pilots weren't happy. Why is this relevant?

Because it shows how important the test pilots views are

Not only has Crumpp failed to realise that this is a flight sim, with all the variables of hardware and software adopted by players, he is also proposing to make the Spitfire so hard to fly by inexperienced gamers that many will just give up after constantly crashing and burning, or having the plane fly apart, as soon as they make a small mistake. He also wants to deny players even the option of using the Spitfire's good stall characteristics.

What were your five results, what were your expectations and how did you come by them?

Yes they are very intelligent, disciplined, and highly educated. It is one of the toughest jobs in existence.

I am sorry. Do I need your permission to get ratings, train, and get a job flying? You are not hireable as a PPI.


Who do you people think you are????

If I had the time I would. Why do you think it has taken so long for me to get the post's out in this thread.

I don't put food on my table by helping to develop realistic flight simulators.

However, I have another source of income, a family to support, and all the things that come with that.

Mel Gough was a test pilot for the NACA.
The quote is in the context of the meeting to determine stability and control standards for the individual services, the US Navy and Army Air Corps.

The NACA already had developed stability and control standards and Mel Gough was a co-developer of those standards.

The end result is the document posted below. It did not result in things being left up to "how much instability one can stand".

In fact, Mel Gough was one of the pioneers in eliminating the "pilot opinion" standard.

http://www.google.com/url?sa=t&rct=j...I69j8yvj-7PvKg

The result is attached. It is the quantified answer to the question, "How much instability can one stand?"

In England, Jeffery Quill was the Chief Test Pilot for the development of the Spitfire. If it met his standards in his opinion, without quantification, it went forth despite the some early testing investigating the longitudinal instability, his acknowledgement, and all the warnings found in the Operating Notes that are the result of longitudinal instability.

It was not until the design was evaluated under a set of measured and defined standards that the longitudinal instability was quantified and fixed in the Spitfire.

And supposedly the clod spitfire doesn't in YOUR opinion meet some standards in your mind that you refer to without quantification.

All this stuff about things being measurable and to defined standards then when asked how you find them in the Sim all we get is:

"Fly the airplane in the buffet and time your turn.

Pull back on the stick, release, and note the behavior of the airplane.

Fly at Vmax, pull hard back, hold it at full deflection, and note the behavior.

Fly the airplane trimmed for slow flight, let go of the stick, fire the guns, and note the behavior.

I have played the game and note the behaviors as I play. Just because I don't spend my time making excel spreadsheets does not mean the points are invalid."

When others actually go out there test and document and show their results you jump on them questioning every detail of their efforts. ... what were the conditions etc etc.

Please give us a break and at least practice what you preach !

Can you explain this further. Fixed As a result of NACA? How? Surely not.

Can we have a analysis of figures 16 17 & 18 pointing to the instability in these test? It would appear tha 15 is an anomaly when compared to the later test.

It is different conditions.

In Figure 15 we see the result of the pilot just pulling the stick back and entering a turn. That is the inherent stability of the aircraft without pilot input. It tells us the workload the pilot needs to exert.

In figure 16, he pushes the stick forward in the measuring equipment.

In figure 17 and 18, he demonstrates the stability thru careful flying.

Figure 15, In other words it is the measured results of what happens if you are new player and you turn the Spitfire and keep the stick pulled back like a stable aircraft to maintain the turn.

In figure 16 we see the proficient but not the expert at controlling the aircraft. He pushes forward and his ability to control the aircraft improves. He still is not getting that steady level of acceleration.

In figure 17 and 18, we see the pilot carefully matches the unstable accelerations to produce a steady level of acceleration.

Klem,

The aircraft in the game acts stable both static and dynamic. It returns to trim and dampens the oscillation. Only in a steady state climb does it begin to act neutral.

I don't know the games code, but it seems like they made it "just statically stable" in level flight without the dynamic instability. When an aircraft enters a climb, the stability margin is reduced so we see the neutral static stability.

The spin modeling is excellent for a game. It took an average of at least two turns to recover when correct input was held. I liked it.

The stall behavior when reached is good too.

The issue is the amount of control required to maintain a turn is not representative of the longitudinal instability.

The inability to exceed the airframe limits. You can pull as hard as you want on the stick without fear of breaking the airplane.

The buffet effects are under modeled. In the game, The turn rate improves IN the buffet without any advantage for correctly flying a maximum turn rate performance turn. The turn performance does not begin to taper off until just before the stall when the slope becomes rather steep. That is not correct. Turn rate should decay in the buffet as a function of the strength of the buffet.

The buffet itself is under modeled. It is like a nibble when we see from the NACA report it imparted noticeable accelerations on the aircraft. Those accelerations are quantified in figures 13 and 14 of the NACA report.

In other words, your turn rate in the game improves in the buffet until just before the stall point and the airplane does not shake as the real thing.

That is part of the stall warning. The idea is to have it so you know to back off and not stall. It is essential to the control of an longitudinally unstable aircraft to have that large and distinct stall warning as well as the ability to maintain control in it. The large accelerations warn of the impending stall and increase the power required to make the turn. This also encourages realism. He rewards the players that fly on the edge to the nibble and back off to smooth air. It has the added benefit of precisely defining that point to an experience player.

I am sorry if that is your perception. It is not the case or my intention.

I only post to try and help the testor's efforts.

For example, posting aircraft performance test's without the conditions for both aircraft and atmosphere does not tell one if the airplane is performing at it should under other conditions.

It should not be surprising that those questions come up when the information is not presented only the results.

Alas Jeffrey Quill - he spent thousands of hours in flight, testing and developing real Spitfires in real conditions, and thus we find out that he had no idea of what he was doing by an American sitting in front of a computer who had "tested" the Spitfire a couple of times on a flight sim and he did find it wanting. And because of Quill Spitfires went forth unstable and drunken in their flight.

Thus it was the Yanks who came to the rescue and fixed the hitherto unstable machine by waving their magic flight reports and inertia weights and speaking in unison "Fix this Spitfire it does not meet our standards!" The British quavered and lo! they fixed the Spitfire forever. And the tale told by Quill, that the inertia weights were fitted after the discovery of badly loaded Spitfire Vs in Fighter Command service was horse pucky.

1. Did inertial weights get added to the design to fix the Longitudinal instability....YES.

2. Did this occur during the Battle of Britain.......NO, the longitudinal instability was not fixed during the Battle of Britain.

3. Should the Spitfires modeled in the game exhibit the longitudinal instability.....YES.

4. Do they now exhibit the longitudinal instability in the game....NO.


As "yanks coming to the rescue"....that is a very myopic view and far from the truth.

It was Gates and Lyon's efforts that brought a measureable standard to the UK aviation authority. Yes he based those standards on the NACA's efforts just as the NACA based part of their standards on his work.

And I suppose they added the inertial elevators to the Spitfire Mk I because nobody in the RAF could read a load plan or do a weight and balance?

I am sure there was an issue in the Mk V when it first came out with the operators incorrectly loading the aircraft. That certainly did not help the longitudinal instability of the design making a bad situation much worse, but it was not the reason for the longitudinal instability.

The inertial devices added to the elevator control is the fix for the longitudinal instability.

You add weights to the control and those weights act to artificially increase the amount of control force required.

Maybe, but it is not because the stability and control characteristics are modeled in the game or that they cannot be modeled.

More to do with community politics than aircraft behaviors.

I thought you all wanted realism in your game. I see that is not the case.

LOL When you have spent 1/10th of the time that many of us have supporting realism, providing original source documentation,testing utilities, face to face meetings overseas with the devs and testing in the IL2 classic and IL2 CLOD come and talk about not wanting realism.

So....can we have a 109 thread now?

OK, let me stick my neck out a mile and try to find some common ground.

I'm no aerodynamicist but all Crump is saying is that the low level of longitudinal stability of the Spitfire is not properly represented in the game and the buffet/stall characteristics are not right. I haven't tried it or flown it on the edge (I've only flown it once since the patch) so I don't know but it would be nice to have the characteristic and helpful pre-stall buffet and I think what Crump is saying is that the FM doesn't provide it.

However I think most of us are currently concerned with more significant issues like it is (was?) too damn slow and perhaps that has led to a low tolerance level for this particular issue. Again, I haven't tried the Spit more than one sortie because I've been concentrating on the Hurricane which is also too slow. Whether it is the power modelling of the Merlin III, prop modelling, drag modelling or some other aspect we don't know either but that's another thread.


I think the basic argument may have value but what does come across is entrenched attitudes on a personal level and arguments about whether NACA findings should or should not be used. Apparently these came much later but should they be used as a reference if they are correct for the Spit MkI/II? Their validity has been challenged because of NACA's own admissions about possible errors. OK, forgive me for not trawling through all 94 pages of the thread but where are the relevant RAE or A&AEE or other British data for the same problem? If longitudinal instability was a fact the data should show that and the thread could come back on track.

Perhaps instead of binding himself to NACA Crump would accept historical data other than NACA's and use that in his explanation of "Stability and Control characteristics of the Early Mark Spitfires". His point should hold good if the basic premise is correct, i.e. longitudinal stability is not modelled properly.

The real shame of the thread, whether you agree with NACA or not, is that Crump set out to explain something and it has been shoved off track by arguments of various kinds including red herrings like differences in players joysticks. As several early posts said, its something worth pursuing in the battle to get the FM as near correct as possible. Just need to agree the data.

This thread has run its course and im a little over the number of reported posts from both sides of the argument. :rolleyes:

If Crump wants to provide Game test data or observed and documented characteristics and furnish the developers with the supporting valid realworld data (NACA or other I dont care). He can do it in private directly to Ilya, this thread has had more than enough time and data thrown at it to "prove" his theory if its correct. This thread is just causing more and more heated arguments and personal attacks and has failed to be objective. And yes I have read most of it because Ive had to moderate it continuously.

Personally I dont see the point of wasting this much energy on a single characteristic of a single aircraft at the expense of all other aspects and all other aircraft. In doing so it would unbalance the game and overall flight model of the aircraft in question. I would also have to question whether Crump holds an objective view of this flight characteristic and flight data given the single bloody-mindedness of the argument.

The developers have their criteria and approach to modelling flight characteristics and should not be pushed to change a FM based on one persons argument against the community. While I am impressed by the amount of research and data and the extreme effort to prove the spit was unstable, where was the game testing data to back up that infact the FM is incorrect? Nada, zero, zilch... so I have to conclude this is just a massive one-man-band trolling of the community.

"bloody-minded - stubbornly obstructive and unwilling to cooperate"
Sound like some people we know? I dont mean just Crump either.

Sorry If im a little blunt and short on patience but Ive put up with the fallout from this thread for almost a month now and I think thats a pretty fair run given how badly it deteriorated on more than one occassion!

I hope you see Ive tried to be fair but its now passed that point and Ive given Crump advice on how to continue his effort if he chooses.
We have more than 30 reported posts from this thread. I think that says enough.