What is "aircraft stability" - IN VIDEO

[Crumpp]

Hurricane testing next to the Spitfires

Absolutely, by careful flying, a skilled Spitfire pilot can match the precision found in a stable aircraft.

That is not the issue.

The issue is the Hurricane does not require such attention to achieve and hold a precise acceleration. The Hurricane is stable.

[JtD]

Originally Posted by Crumpp

Absolutely, by careful flying, a skilled Spitfire pilot can match the precision found in a stable aircraft.

It's stick free behaviour.

[Crumpp]

It's stick free behaviour.

What are you talking about???

The Hurricane abrupt turn as recorded by the NACA is stick fixed. The Spitfire abrupt turn as recorded by the NACA is stick fixed.

The RAE stability measurements for general stability characteristics are stick free.

In both the RAE and NACA measurements, the Spitfire was longitudinally unstable with unacceptable characteristics.

That is why they added the inertial elevator to fix the longitudinal instability.

What is the issue? Why is blatent fact so hard to understand?

All the smoke, mirrors, and baloney put out about "it is normal" and "all fighters of the day" acted like that is pure fantasy.

If there was not a problem, then they would not have fixed anything!!!

[Crumpp]

Answer the question JtD:

Why did they modify the aircraft with an inertial elevator?

[fruitbat]

Originally Posted by Crumpp

Answer the question JtD:

Why did they modify the aircraft with an inertial elevator?

Heres a question.

If they realised that they needed it for the MkV which no one disputes, why did they not come to the same conclusion for the Mk I in 1939?

It wasn't new tech.

And it has SFA to do with NACA, since they added Bob weigths to the MkV before NACA ever got there Spit V to test.

[Crumpp]

why did they not come to the same conclusion for the Mk I

The Mk I recieved an inertial elevator in July of 1941.

[fruitbat]

Originally Posted by Crumpp

The Mk I recieved an inertial elevator in July of 1941.

Did it, what Mk I's were those then.

Mk I was out of service and MKII's and Mk V's in service then.

I know what your desperately using as your source for that claim, and its one of the hundreds of modifications listed in Morgan and Shacklady, which coincidentally were all the modifications that were applied to the MKV, which led to need of Bob weights due to CoG being changed, AFTER BoB.

Again i ask you, if it took the RAE 2 months do decide that they needed bob weights on the Vb, why 3 years for the Mk1 in your world?

[JtD]

Originally Posted by Crumpp

What are you talking about???

You should know, you even highlighted it on the previous page, but in case you really can't figure it out - I am referring to phugoid and spiral modes, I've only said it about 5 times, so maybe it was lost on you. Phugoid, spiral. That's all I'm talking about. I do this because you keep bringing up an A.&A.E.E. chart supposedly illustrating how poor the Spitfire's stability was, where it shows nothing but long period oscillations, i.e. phugoid and spiral mode. This chart shows nothing out of the ordinary for a high speed fighter of that day and the characteristics shown are way better than that of the Hurricane. It appears to me that up to this minute, you don't even know what you're talking about, and yet you've made 100+ posts on the issue trying to convince innocent bystanders of something that's plainly wrong.

It is really getting on my nerves, and here it is in short form, so I can simply quote me every time you bring that chart up again out of context:

The A.&A.E.E. stability records for Spitfire K.9788 show stick free, long period dynamic stability characteristics, also known as phugoid and spiral mode. The records show typical behaviour for world war 2 fighter aircraft, and the characteristics are clearly better than those of other contemporary aircraft, in particular better than the characteristics of the Hurricane, which was also tested by the A.&A.E.E. at the same time.

[TomcatViP]

JTD the pitching moment decrease with the thickness of an airfoil. Tht's how simple it is.

The great challenge in the 50's with the thin wing design and their lack of stability came with that. The video show how the lift center is moving frwd. This move is faster when the thickness ratio decrease. This is why most of the designer during WWII did stick to the 15% ratio.

Supermarine did not have all the viscous flows knowledge as other did and ran straightforward in the thin wing solution (just like the Brits did in WWI). Hence the long dev process. of the Spitfire. That's simple.

Other planes had flaws inherent to their design and did take as long to be fully flaw free.

[JtD]

OK and thanks for the information as such.

It changes nothing about what I wrote, though, if you meant to refer to that.