4.101 RC - List of fixes

[Fenrir]

Because Tihi, you don't know what you are talking about and someone threw you a bone to shut you up.

I'm a Spit flyer. So no lufty bias here.

What was fixed in 4.101 was an aileron trim issue, nothing to do with stability.

As for your perceived instability - I've been flying the 4.10 & 4.101 spits for a month now, I see a very low trim elevator neutral trim speed, which I find questionable (but having been shown the source of that by TD I cannot argue because I have no data with which to counter) but there is NO behavior AT ALL which indicates pitch instability. The a/c does NOT tighten up in turns, does NOT hunt whilst flying straight and level and can be trimmed quite easily to fly hands off.

As the aerodynamically understood principles of instability go the 4.10/4.101 Spits are paragons of stable aircraft.

If however you are referring to the adverse yaw, this has been discussed. Try applying a little rudder with the direction of aileron - this is called a coordinated turn - and your problem should go away; after some practice, naturally.

[PE_Tihi]

Originally Posted by Fenrir

Because Tihi, you don't know what you are talking about and someone threw you a bone to shut you up.

I'm a Spit flyer. So no lufty bias here.

What was fixed in 4.101 was an aileron trim issue, nothing to do with stability.

As for your perceived instability - I've been flying the 4.10 & 4.101 spits for a month now, I see a very low trim elevator neutral trim speed, which I find questionable (but having been shown the source of that by TD I cannot argue because I have no data with which to counter) but there is NO behavior AT ALL which indicates pitch instability. The a/c does NOT tighten up in turns, does NOT hunt whilst flying straight and level and can be trimmed quite easily to fly hands off.

As the aerodynamically understood principles of instability go the 4.10/4.101 Spits are paragons of stable aircraft.

If however you are referring to the adverse yaw, this has been discussed. Try applying a little rudder with the direction of aileron - this is called a coordinated turn - and your problem should go away; after some practice, naturally.

And you seem very sure you know what you are talking about? I studied aerodynamics, you know. Did you, or did the guy who threw me a bone, as you say?

I really wrote more then enough here, but let me recapitulate shortly:

If the rudder or some other control is moved energetically to push the nose down in a stall climb, this causes slow ( ~ 0,7 Hz) and very strong pitch oscillations, (amplitude like 45 deg or more relative to the flightpath direction). They do not get damped to sufferable level before plane reaches something like 200 kmh in the dive. No other plane in the game behaves nearly so wild.

As for the reasons why your Spit pitches up the nose wildly, almost certainly the reason is TD moving the CG backwards. CG position is the MAIN pitch stability factor. That s why the above happens. And I wrote that already here, a page or so back. Take a look at the picture there.

The effects are most obvious in slow flight, near stall; and still strong enough at combat speeds to spoil the aim. And the plane is instable laterally, too.
If you cannot see anything of the above in flight, I cannot help you further.

What they sold you as a reason for the planes bad pitch trim, I do not know. After seeing their FM work here, I do not care, either.

[JtD]

From last three pages:

Originally Posted by PE_Tihi

I do not know...

Originally Posted by PE_Tihi

I do not know...

Originally Posted by PE_Tihi

I do not know...

Originally Posted by PE_Tihi

I do not know...

Originally Posted by PE_Tihi

I do not know...

That's exactly the message I'm getting. I think you should follow your own advice.

Originally Posted by PE_Tihi

am sure anyone googles it out in 5 minutes

[PE_Tihi]

Originally Posted by JtD

From last three pages:





That's exactly the message I'm getting. I think you should follow your own advice.

That may not be your case, but there are things I do not know, you know
Fenrir above knows, just like you do, I do not even know what a coordinated turn is
What should I do after flying the game 9 years, some 3-4 of them with pedals, but laugh LOL!

Sorry, guys, but I am really wasting my time here on some of you, am I not?

[Fenrir]

Originally Posted by PE_Tihi

And you seem very sure you know what you are talking about? I studied aerodynamics, you know. Did you, or did the guy who threw me a bone, as you say?

Well then you surely must understand the principles of gyroscopic precession; the reason why when you push or pull the nose up or down in pitch you get a reaction in the yawing plane. The reverse is true too, you know, which is why:

Originally Posted by PE_Tihi

If the rudder or some other control is moved energetically to push the nose down in a stall climb, this causes slow ( ~ 0,7 Hz) and very strong pitch oscillations, (amplitude like 45 deg or more relative to the flightpath direction). They do not get damped to sufferable level before plane reaches something like 200 kmh in the dive. No other plane in the game behaves nearly so wild.

Ah, so now you talking about longitudinal stability, which has nothing to do with elevators; for what it's worth the later Spit marks were always somewhat behind the curve when dealing in vertical tail surface area with each progressive increase in power - so at low speed you don't have enough airflow going over the fin/rudder to provide adequate compensation for your power setting - no surprise, and until we get a pilot in here who can authoritatively comment on the planes behavioural characteristics under such flight conditions, we are gonna have to trust TDs judgement.

Originally Posted by PE_Tihi

As for the reasons why your Spit pitches up the nose wildly, almost certainly the reason is TD moving the CG backwards. CG position is the MAIN pitch stability factor. That s why the above happens. And I wrote that already here, a page or so back. Take a look at the picture there.

There are many reasons not just CofG for trim change, and if you'd studied aerodynamics as thoroughly as you claim, you'd know this. Trim change can be accomplished through airframe/fixed surface/moving surface design and even by the manner of mass balance - to accuse TD of moving the CofG position, well, you assume too much. Especially as the spits do not exhibit any of the other criteria to warrant an accusation of pitch instability.

Originally Posted by PE_Tihi

The effects are most obvious in slow flight, near stall; and still strong enough at combat speeds to spoil the aim. And the plane is instable laterally, too.

Wow, a 1600hp aircraft at slow speed tricky to handle? With little air moving over flight surfaces and a massive torque reaction?

Originally Posted by PE_Tihi

If you cannot see anything of the above in flight, I cannot help you further.

I see a little more longitudinal reaction to aileron input, but not catastrophic, I see a low elevator trim speed with no pitch instability, and bugger all instability laterally unless i'm flying with the rudder badly trimmed. Personally, I think you have controller issues, or you need practice to get the best out of the spit.

Originally Posted by PE_Tihi

What they sold you as a reason for the planes bad pitch trim, I do not know. After seeing their FM work here, I do not care, either.

They showed us all a pic of a modern day restored Spitfire flying in formation with a photo a/c at low airspeed with significant down elevator deflection.

Tihi, I suggest if you want people to listen to your issues then you provide quantifiable data or a series of pilot reports - and much more than one - that backup your arguments or that at least point to a common extrapolated outcome.

Currently you come here with nothing more than opinions delivered with a exasperating sense of melodrama and an irritatingly belittling attitude towards the guys at Team Diadalos - you win no friends and thusly make any chance that your grievances might be even investigated, let alone fixed, marginal at best.

[PE_Tihi]

Originally Posted by Fenrir

Ah, so now you talking about longitudinal stability, which has nothing to do with elevators;

You confuse the lateral and longitudinal stability; longitudinal certainly has to do with the elevators.

Originally Posted by Fenrir

"...almost certainly the reason is TD moving the CG backwards...
...."

There are many reasons not just CofG for trim change, and if you'd studied aerodynamics as thoroughly as you claim, you'd know this. Trim change can be accomplished through airframe/fixed surface/moving surface design and even by the manner of mass balance - to accuse TD of moving the CofG position, well, you assume too much. Especially as the spits do not exhibit any of the other criteria to warrant an accusation of pitch instability.

'Almost certainly' is an acknowledgement they may be other reasons. That is improbable because the much reduced longitudinal stabillity of the plane compared to 4.09. indicates the CG has been moved backwards relative to its 4.09 position.

You say in a previous post 'there is NO behavior AT ALL which indicates pitch instability. The a/c does NOT tighten up in turns..'
For the 'turn tightening' to appear, CG has to be BEHIND the plane AC, which would make the plane completely uncontrollable- ie. instable in the absolute sense. If that s your criterion for where the bad stability and handling begins, please better avoid flying your designs yourself

And if you see 'no pitch instabillity at all' here, then am not going to waste any more time explaining. I wrote enough in the thread.

"They showed us all a pic of a modern day restored Spitfire flying in formation with a photo a/c at low airspeed with significant down elevator deflection."
How on earth do you find this a proof of anything else, but the Spit having the movable elevators? Next second the elevators could 've been in another position. Or do you beleive formating pilots have orders against moving their controls?

Regarding the belittling attitudes, etc, please refer to your posts here. As for the TD, their job are not anyone's grievances; they took over modifying an FM in an acceptable manner.

[Tempest123]

...opinions delivered with a exasperating sense of melodrama and an irritatingly belittling attitude towards the guys at Team Diadalos - you win no friends and thusly make any chance that your grievances might be even investigated, let alone fixed, marginal at best.

+1

...these silly arrogant posts aren't doing anything except annoying the c**p out of everyone. No one wants to join a discussion where their opinion will be belittled. I like FM debates, I even started one! But not ones with pointless pissing contests, I don't need to feel like I'm back in junior high.

Rant over!

[MD_Titus]

Originally Posted by Fenrir

Because Tihi, you don't know what you are talking about and someone threw you a bone to shut you up.

I'm a Spit flyer. So no lufty bias here.

What was fixed in 4.101 was an aileron trim issue, nothing to do with stability.

As for your perceived instability - I've been flying the 4.10 & 4.101 spits for a month now, I see a very low trim elevator neutral trim speed, which I find questionable (but having been shown the source of that by TD I cannot argue because I have no data with which to counter) but there is NO behavior AT ALL which indicates pitch instability. The a/c does NOT tighten up in turns, does NOT hunt whilst flying straight and level and can be trimmed quite easily to fly hands off.

As the aerodynamically understood principles of instability go the 4.10/4.101 Spits are paragons of stable aircraft.

If however you are referring to the adverse yaw, this has been discussed. Try applying a little rudder with the direction of aileron - this is called a coordinated turn - and your problem should go away; after some practice, naturally.

the nose up tendency does seem rather exaggerated, wasn't it something to do with maximum cruise economy rather than combat cruise speed being used as the elevator trim neutral point?

[JtD]

No, that was aileron trim, and it has been changed.

[PE_Tihi]

Originally Posted by jtd

no, that was aileron trim, and it has been changed.

loll!