Spitfire Mk IX - stability issues

[artik]

Yestoday I have flown Spitfire Mk IX at CT (I think it was first time I did number of real sorties in Spit 9 in AH2).

I have noticed it is not stable as it was in AH1. In AH1 it was allmost easy mode plane - now I've get stalled too much time with not hard stick pulls at all. After short time I started to control it much better but anyway it is not seems to be the same.

Actually I'm not spit player (I allmost do not fly it) I fly mostly 109G and know to handle it well but I found Spit less stable then 109.

Maybe just I forgot how to fly Spits.......

What can you tell? What is your opinoin?

P.S.: I never fly with stall limiter or combat trim I like to control plane myself

[Kweassa]

Some planes were enhanced in overall stability, others were greatly reduced.

 For instance, IMO the US planes are among the most enhanced in basic stability.

 They were always very reliable at slow speeds with flaps even in AH1, but in AH2 they are even better.

 While the turning radius itself doesn't seem to have changed much, a few notch of flaps will let the US planes pull hard AoA without much worries of abrupt stall. The P-51s can actually afford to duke it out with La-7s and Yaks in pure knife fights, and even the P-47s can easily out maneuver 109s during slow speed brawls.

 The La-7 and La-5FN is also much more stable at slow speeds.

 On the contrary, the Bf109s are a bitc* to fly now. Pulling AoA near stall will almost immediately flip the plane over. A decent P-47 will outturn a 109 within one circle turn, because the 109 just can't ride the edge of the stall like it used to. No matter how hard you pull the stick, at whatever speed(not just in high speed turns) the P-47 will just pull harder AoA without stalling. In the 109s, the moment you hear the stall alarm it will start to wiggle. Only a F-4 or a E-4 stands any chance in outturning any US plane - all the G models - G-2, G-6, G-10 - are easily outturned by all US planes.

 The Spitfires in AH2, are all very sensitive to rudder input. In AH1, I used to pull a lot of deflection shots with momentarily max stick pull with hard rudder. This used to kill speed at a very fast rate, and sort of 'barge' the plane through the edge of stall. I typically remember the situation by the sound. Despite the stall warning sound(I use the buffeting sound for stall.wav)  the Spit would still maintain that turning radius for a very long time with hard sticj pull and max rudder.

 However, in AH2, abrupt rudder will destabilize the plane. The spits are still one of the most stable planes in the set, but they just aren't what they used to be.

 Even the Hurricane and the A6M has simular problems now. Even with plenty  of speed a harsh stick pull will flip a Zero over. In AH1 the Zeros were virtually stall-resistant - and only when the speed dropped so low that the plane couldn't fly any longer, it stalled out. Well, not in AH2.

 .........


 I understand this to be a good thing. Like the 109, the Spitfires are small, light planes equipped with powerful engines. I can understand the fact that these planes will suffer more due to torque.

 However, I do have some gripes about the US planes now. I like it that the US planes aren't the 'pigs' they used to be, and are very versatile and dangerous planes. But I'm kinda thinking their stability issues may be a bit overdone. Just a feeling, nothing solid.

[VO101_Isegrim]

The NACA found in tests that the Spitfire has markedly low longitudal stability - this is probably due to the plane having very light elevator (too light in the NACA`s opinion), and of course stability and manouveribilty are confronting charactheristics. If the plane was manouverable around an axis, it was neccesary unstable in that axis, too. For example, the 190 was stable at all axis expect in the roll axis - it had exceptional roll rate; the 109 was stable in all axis expect directionally - it was known for having a powerful rudder.

[artik]

For 109G-10 I didn't mentined any changes. It allways had very good rudder input that had allways helped me to control it on high AoA - or recover it from stalls. When I get into spitfire I had found it is very hard to recover stalls and it is very sensitive for hard stick input.

I had never had problems with its stabilty - anyway I never used to turfight in it when for spitfire is is much different - you mostly have to make angles fight becasue of lack of speed.

Don't know about US planes - it is interesting - I allways had problem to control Pony (one of the reasons I didn't liked it - besides most its problem - low climb ratio in comparsion with 109)

Thanks, for interesting information

[Angus]

The Spitfire flying Characteristics...
From German Pilot Hans Schmoller-Haldy, a 109 Pilot from Jg 54.

"I was able to fly a captured Spitfire at Jever. My first impression was that it had a beautiful engine. It purred. The Engine of the Messerschmitt was very loud. Also the Spitfire was easier to fly, and to land, than the Me 109. The 109 was unforgiving of any inattention. That was my first and lasting impression"

Wonder if this thread will heat up from this, - hopefully not too much


Anyway, I have to agree. The Mk IX is tougher than it was. But bear in mind that ours is a high alt variant, and while being heavier than the Mk V, at low alt it has not much more power.
In AHI it was frigging Uber, now not so much any more.

[Crumpp]

The Spitfire was hands off stable.

http://www.thetongsweb.net/AH/EAAjanuary1999.pdf

Crumpp

[MiloMorai]

Issy failed to mention that the Spit had mods done to 'heavy up' the elevator, but that is to be expected from him.

He also failed to mention that some  Spit pilots did not like the mod.


Kurt tank on the ailerons of the 190: "After aileron input the plane returned back to its neutral position."

quote:
the 190 was stable at all axis expect (except???) in the roll axis

[VO101_Isegrim]

Look up the NACA report on Spitfires and Eric Brown`s comments on 109s/190s, to improve your view on the subject.

And Angie, you should REALLY spend some time reading scientific reports on your favourite fighter, rather than relying all the time on anecdotes.

ie.

"The longitudal handling characteristics of the Spitfie were observed to be poor in rough air. This behaviour was attributed to the airplane`s neutral static longitudal stability and relatively light wingloading..."

and conclusion no.2

"In all flight conditions the stick fixed longitudal stability was either neutral or unstable, and therefore failed to meet the accepted requirements. The requirement for stable stick force gradient was not met in all conditions of flight except for the condition with flaps down, power on."


And Milo, can we see an exact source how bob weights would 'cure' instability ? According to Milo, bob weights were a cure for EVERYTHING. Well, they may cured wing breakages on the Spit, to an acceptable extent, at least..

[MiloMorai]

Originally posted by VO101_Isegrim
Look up the NACA report on Spitfires and Eric Brown`s comments on 109s/190s, to improve your view on the subject.

And Milo, can we see an exact source how bob weights would 'cure' instability ?

According to Milo, bob weights were a cure for EVERYTHING.

Again with your inability to read/comprehend English Issy.

"The NACA found in tests that the Spitfire has markedly longitudal stability - this is probably due to the plane having very light elevator "

Never said it cured everything.  But, the the bob weights helped eleviate the marked instability you so much like to harp on.

If you are going to tell 'stories' Issy don't just tell part of the 'story'. It is well known how much you so love the Spitfire.

[VO101_Isegrim]

[Angus]

Issy, you're at it again, yer  ####-end.
This anecdotal evidence is unfortunately from a German 109 fighter pilot trying his hand at a Spitty for the first time.
Anecdotal, but still there. How do you measure HANDLING EASYNESS by tests anyway? This 109 pilot, after ONE FLIGHT already finds the Spitty easier to handle and land than the 109! Does that count as anything or are you coming again with "its a LIE" statement?

You mentioned Spitfire longitutional instability. That was a true problem in a line of the Mk V series and later on in the Mk 21 (same problem as the P51 there, fuselage tank)
It was cured by Bob-weights, making the elevator heavier, steadily growing heavier with G.
The cure was good. The Spitfire from late Mk V onwards was longitudionally calibrateable.

Anyway, I am somewhat offended by some persons disbelief of anecdotal evidence, especially in fields where there is very little or none test data versus anecdotal evidence corresponding nicely between hundreds of pilots of both/many sides of WW2. I consider that as a lack of maturety.
Anecdotal evidence is forwarded as it is, - it can be discussed and debated against other anecdotal evidence. But I'll bloody well take a WW2 Pilot anecdotal statement against an Izzy-ediet calculation any day!!!!!

[Crumpp]

Izzy,

I think you are confusing stick forces with stability.  The Spitfire had horrible control forces harmony.  That did not make it unstable or hard to fly.

In fact Werner Molders called the Spitfire "Childishly easy to fly".

It was very honest airplane that gave it's pilot ample warning when it was near the edge of it's envelope.

IMO the Spitfires handling characteristics, which are totally different from it's performance characteristics, are what kept the RAF pilots alive in the early days of WWII.  

The RAF was forced to send pilots with very little Air-to-Air Combat training into the fray early in the war.  Gentle handling allowed them to fly at the edge, survive, and learn.

When the situation was reversed in 1944 and the Luftwaffe was forced to send under trained pilots into combat things were different.  Neither the 109 nor the 190 had gentle handling.  The 190's especially were not an "honest" airplane.  It could fly right up to the edge of its envelope with no warning as to how close a pilot was to stalling.  Its vicious stall ensured fledging combat pilots did not "push" the plane.  Since they could not "fly at the edge" many of them died in their initial combats with no chance to learn.

The Spitfire's performance was good on top of it's gentle handling.  IMO it was the premier angle fighter in the European Theater.

Angle fighting is also much easier to learn and more natural for a beginner to master.  Human nature wants to lock on the enemies tail, never lose sight, and follow them around the sky, knowing at any second they will be in your gun site.

Energy fighting takes skill and discipline to master.  It's not natural to let the enemy go and extend, lose sight of them for a second on the reversal, or point your nose not at the enemy but where you think he will be to make a snapshot.

Given two airplanes with very similar flight envelopes, it is the one who can fly closest to the edge that will win.

Anyway, I am somewhat offended by some persons disbelief of anecdotal evidence, especially in fields where there is very little or none test data versus anecdotal evidence corresponding nicely between hundreds of pilots of both/many sides of WW2. I consider that as a lack of maturety.

Exactly!  In every instance I have found so far if you check out the science it backs up the anecdotal evidence.

A simulation is not a simulation if you cannot reproduce the anecdotal evidence as well.  The Science and History work together IMO.

Crumpp

[Angus]

Jolly Well Agree Crumpp M8!
Here is a nice line from you:
"A simulation is not a simulation if you cannot reproduce the anecdotal evidence as well. The Science and History work together IMO. "

Nail hit on the head if I may say so. And in my humble opinion, HTC has done a ver very very very good job on this, always on the search for improvements.

[Crumpp]

Nail hit on the head if I may say so. And in my humble opinion, HTC has done a ver very very very good job on this, always on the search for improvements.

Definately agree.  

Crumpp

[Guppy35]

Originally posted by VO101_Isegrim


And Milo, can we see an exact source how bob weights would 'cure' instability ? According to Milo, bob weights were a cure for EVERYTHING. Well, they may cured wing breakages on the Spit, to an acceptable extent, at least..

Supermarine Cheif Test Pilot Jeffrey Quill devotes a chapter of his book "Spitfire-A Test Pilot's Story" to the issues of longitudenal Stability and Range Issues.

He speaks at length on the bob weights and their use and the effect it had in helping increase the stability.  He also goes on to describe how increasing the elevator horn balance also made a big difference.

Too tired to quote the entire chapter however

Not sure what you want, but I'll type of specifics from the book if you want

Dan/Slack