Why is the Spitfire Mk IX still unstable??

[Crumpp]

Yo-Yo says:

What's an epic battle! And most of the warriors for stability already fly fully loaded 109K that is unstable at low speed with full power.

 

Yep...

 

You know that was pages of conversation too, LOL. :megalol:

[MiloMorai]

What's an epic battle! And most of the warriors for stability already fly fully loaded 109K that is unstable at low speed with full power.

 

Is the spitfire to have a rear fuselage fuel tank? If not, then there has been a lot of noise about nothing.

[Yo-Yo]

Is the spitfire to have a rear fuselage fuel tank? If not, then there has been a lot of noise about nothing.

 

I really have not investigated this matter so deep. My old statement about Spifire was based mostly on the Mk V stability curves. And that time I did not dig 109K :).

Later I suggested that Mk IX can have CG more forward (I had not collected exact data for weigh and balance for Mk IX that time), and the sign of it could be the increased compensation for the elevator on the later modifications - and it was, as far as I was told.

 

So, before the active work on Spitfire beginning I can say that Mk IX due to the same airframe and different CoG position will have low positive stability. At least in power-off condition. What about full power condition... let's see, but as the engine is much more powerful it can be neutral or unstable, let's see...

[bongodriver]

Doesn't matter if it does get the rear tank, once 34 gallons have been burned then there should be no difficulty in handling the aircraft.

[NineLine]

Doesn't matter if it does get the rear tank, once 34 gallons have been burned then there should be no difficulty in handling the aircraft.

 

Doesn't sound like no difficultly completely, less difficult maybe...

 

This test is from 1945 though, did the iX use or have the rear tanks in 44 at all?

Spitfire_IX_ML-186 LR Tank Handling.pdf

Edited October 21, 2015 by NineLine

[JtD]

BTW, It is not hard to convert the NACA MAC to RAE arm and moment.

That's true, and yet you failed.

[Kurfürst]

...did the iX use or have the rear tanks in 44 at all?

 

IMO it would be a waste to begin modelling something that saw doubtful amount of use, and would either not used at all by DCS pilots or if used it would just render the plane useless in DCS. Even the stock Spits range should be enough for Normandy anyway...

[bongodriver]

Doesn't sound like no difficultly completely, less difficult maybe...

 

This test is from 1945 though, did the iX use or have the rear tanks in 44 at all?

 

if the recommendation was for line pilots to engage in combat with that fuel load then it's not difficult, the term experienced pilot is not meant as anything above average in skill, simply a pilot who is in current practice with experience, just as the typical squadron line pilot would be.

I don't know if they had rear tanks in 44.

[Cripple]

Doesn't sound like no difficultly completely, less difficult maybe...

 

This test is from 1945 though, did the iX use or have the rear tanks in 44 at all?

 

Ooooo! That was very interesting reading. I knew from the pilot's notes that the use of rear tank was strongly contra-indicated, yet it was never fully elaborated upon why this was the case. Thanks for sharing that.

 

Links back to what I was trying to say initially though: should be thinking of "Stability" as a sliding scale, rather than an absolute?

[JtD]

It's absolutely a sliding scale.

[bongodriver]

Ooooo! That was very interesting reading. I knew from the pilot's notes that the use of rear tank was strongly contra-indicated, yet it was never fully elaborated upon why this was the case. Thanks for sharing that.

 

Links back to what I was trying to say initially though: should be thinking of "Stability" as a sliding scale, rather than an absolute?

 

yes it's a sliding scale, nobody is really suggesting otherwise, it ranges from stable to neutral to unstable.

[Cripple]

if the recommendation was for line pilots to engage in combat with that fuel load then it's not difficult, the term experienced pilot is not meant as anything above average in skill, simply a pilot who is in current practice with experience, just as the typical squadron line pilot would be.

....

 

Any proof to back that statement up? Cos I'm seeing at least three sweeping and unsubstantiated claims in a single sentence...

 

a) "experienced" equates to simply "above average" in (piloting skill). "Average" is not defined.

b) a pilot who was flying regularly can be considered "experienced"

c) a "typical" pilot in a squadron would be flying regularly enough to be considered experienced

 

(Note: the terms "average" and typical should be made explicit too.)

[NineLine]

IMO it would be a waste to begin modelling something that saw doubtful amount of use, and would either not used at all by DCS pilots or if used it would just render the plane useless in DCS. Even the stock Spits range should be enough for Normandy anyway...

 

I mostly agree, except I am a big fan of options in the ME, maybe it could be considered for that, but some research needs to be done to see if the tanks were ever installed in the variant we ultimately get... if yes, then I am all for having the option, hopefully we will get more than just Normandy in the future.

[Cripple]

yes it's a sliding scale, nobody is really suggesting otherwise, it ranges from stable to neutral to unstable.

 

So, you'd agree that - as it is a "sliding scale" (rather that three discreet states) - one individual's definition of neutral *could* be defined by another as unstable, yes?

 

The definition being mostly subjective and based upon the relative skill and previous experience of the respective pilots.

[MiloMorai]

Doesn't matter if it does get the rear tank, once 34 gallons have been burned then there should be no difficulty in handling the aircraft.

 

And the likelihood of a sim pilot having any fuel at all in the rear tank is ridiculous as one reads for other DCS a/c that not even a full load is carried.:music_whistling:

[bongodriver]

Any proof to back that statement up? Cos I'm seeing at least three sweeping and unsubstantiated claims in a single sentence...

 

a) "experienced" equates to simply "above average" in (piloting skill). "Average" is not defined.

b) a pilot who was flying regularly can be considered "experienced"

c) a "typical" pilot in a squadron would be flying regularly enough to be considered experienced

 

(Note: the terms "average" and typical should be made explicit too.)

 

???

 

you seem to have completely misread it seems or are overcomplicating it.

 

experienced = experienced i.e. someone who is regularly flying the type like an average line pilot would be, there is no mention of piloting 'skill' at all

 

 

So, you'd agree that - as it is a "sliding scale" (rather that three discreet states) - one individual's definition of neutral *could* be defined by another as unstable, yes?

 

No, the 3 states are absolute according to the definition in science.

 

 

The definition being mostly subjective and based upon the relative skill and previous experience of the respective pilots.

 

No

[bongodriver]

I mostly agree, except I am a big fan of options in the ME, maybe it could be considered for that, but some research needs to be done to see if the tanks were ever installed in the variant we ultimately get... if yes, then I am all for having the option, hopefully we will get more than just Normandy in the future.

 

It shouldn't be a stretch to do this retrospectively when that time comes (DCS 1946 :music_whistling: )

[Kurfürst]

Can we please do without the usual semantic arguements...?

[NineLine]

Yeah, I am confused now, an airplane can still have instabilities, but those not be as concerning to an experienced pilot but the FM would still have those instabilities... An experienced pilot might say the Spitfire was easy to fly, even knowing those instabilities are there... if that makes sense.

[Crumpp]

That's true, and yet you failed.

 

What are you talking about and why are allowed a pass making such innuendo?

 

:music_whistling:

 

 

I did that math. Why don't you do the same?

[bongodriver]

Yeah, I am confused now, an airplane can still have instabilities, but those not be as concerning to an experienced pilot but the FM would still have those instabilities... An experienced pilot might say the Spitfire was easy to fly, even knowing those instabilities are there... if that makes sense.

 

Sort of, stability is easy to handle for anyone right up to neutral, once entering the unstable range the test of ability begins, it is literally like and often demonstrated as balancing a ball, with more experience at balancing a ball one becomes better at it no?

 

the stable condition is a ball in a bowl, you need some extra special skills not to be able to handle that, neutral stability is a ball on a perfectly flat surface, you have almost total control over its condition, instability is balancing the ball on top of a convex plane (finger, other ball etc) it can be done with relative ease subject to how far in to the unstable region you go and your capacity for balancing gets better with exposure.

[NineLine]

Sort of, stability is easy to handle for anyone right up to neutral, once entering the unstable range the test of ability begins, it is literally like and often demonstrated as balancing a ball, with more experience at balancing a ball one becomes better at it no?

 

the stable condition is a ball in a bowl, you need some extra special skills not to be able to handle that, neutral stability is a ball on a perfectly flat surface, you have almost total control over its condition, instability is balancing the ball on top of a convex plane (finger, other ball etc) it can be done with relative ease subject to how far in to the unstable region you go and your capacity for balancing gets better with exposure.

 

Yes and no I guess... a pilot that cant handle the instabilities of an aircraft probably never lived long enough to get better at it. Pilots in WWII might not have lived long enough to gather experience to over come whatever level of difficulty the Spitfire might have thrown at them. People that died during Spitfire solo flight training may not agree it was easy to fly, thats something that we really cant ask unless you believe in EVPs and communication with the dead.

 

SO really the discussion needs to remain on the raw data of the aircraft, and less about how a pilot feels about the aircraft. Someone that has flown the Spitfire for years in combat might find it very easy to fly as its become second nature, a new pilot might find it very difficult... a modern pilot with experience on many different aircraft could be tainted somewhat by those experiences, maybe flying another aircraft that is less or more stable would impact their opinion of the Spitfires ease of use...

 

Its like this in any sim as well... you take the 109, at first you might not have been able to handle doing basic flight maneuvers easily... but with practice, those difficulties disappear... to me the 109 is very easy to fly now... but me telling a new player that might cause them to think they should be able to fly it easily right out of the box, again, if that makes sense...

Edited October 21, 2015 by NineLine

[JtD]

What are you talking about and why are allowed a pass making such innuendo?

If you have forgotten what I'm talking about I suggest you read this topic. It's not that long. And there's no innuendo. Just fact. The Spitfire at NACA was not tested with CoG 4.8 behind the datum as you've stated and 22.5 cm are not 11.3 inch as you've stated. The correct figures are ~7 and ~9. Why do you keep discussing this? It's not up to opinion, you've made a mistake and could be happy that you've learned something. Feel free to rant on if it helps you, but that's really all I'll say about this.

[bongodriver]

Al Pinner is a colleague of mine, I have spoken to him about the Spitfire and will take his word over anybody here waving charts and raw data at me.

 

 

 

They now allow the fare paying public to fly in Spitfires in the most unstable condition it is ever likely to have faced.

[NineLine]

They now allow the fare paying public to fly in Spitfires in the most unstable condition it is ever likely to have faced.

 

Ah cool, so you get to ride in it in full combat load out... nice... :music_whistling:

 

When building an FM, I think all you can go on is raw data, the anecdotes help round it out of course... ED is good at letting knowledgeable pilots try their stuff out and give input and tuning from there, ie the P-51D.

 

I think the TFC has a few Spits... I am not too worried about what ED is going to turn out for us.

Edited October 21, 2015 by NineLine