Originally Posted by CaptainDoggles (Post 447067)

First of all, I'm going to disregard things like Active Stability, where you have the computer making lightning-quick corrections to the unstable aircraft to keep it in controlled flight, because I think that this is beyond the scope of what we're talking about here. If we want to get into a discussion on the characteristics of FBW systems and supermaneuverability then we should open a new thread.

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I think it depends greatly on

a) which stability mode we're considering; if it's the short period or the phugoid mode

and

b) what you consider to be "maneuverable".

I think that if you were to reword that statement to read "the relationship of longitudinal stability to agility is inverse. As one increases, the other decreases and vice versa" then I would absolutely agree.

If an aircraft is unstable, then it will by definition be difficult or impossible for the pilot to precisely control the aircraft during a maneuver. By this I mean the pilot won't be able to hold a constant G-level through a turn, or to keep his guns on target.

I would consider such an aircraft to be highly agile, because it can re-orient its lift and nose vectors quickly and easily. This makes intuitive sense, because an unstable aircraft always wants to depart from equilibrium.

But I don't think that the aforementioned aircraft is particularly maneuverable, because I would define maneuverability as being easy to maneuver precisely and accurately through a wide range of maneuvers. In my opinion, if you have to fight the aircraft making corrections the whole time, then it's harder to get it to do what you want it to do, and so it's not very maneuverable, and so I would not consider an aircraft with negative stability to be very maneuverable.

Originally Posted by Crumpp (Post 447085)

:rolleyes:

Once again, a standard is a standard. The Air Ministry and the RAE did not have one.

The United States had a standard during the war. That does not mean every airplane met that standard. Most aircraft were designed before the standard was adopted. It does mean, they designed to meet, tested to meet it, and implemented design corrections to meet the adopted standard. Part of that report and standard is included in the very first post in this thread.

The design firms in the United States were obligated to meet a standard. Supermarine was under NO Obligation to correct the Spitfire. It as already in production and service. It took the NACA, Gates, and mounds of evidence of the instability before a simple correction was adopted.

Originally Posted by Crumpp (Post 447088)

How many actual dogfights did Henshaw get into in an early mark Spitfire??

None.

How many in any Spitfire??

What Mark of Spitfire is that on the magazine cover?? What Mark was the topic of this thread??

Originally Posted by Crumpp (Post 447098)

They knew about it in 1936!! Do you really think Supermarine is that stupid it took them four years to fix it???

It cost's money to add things to an airplane. Even more money to fix an issue that is the designers fault.

Originally Posted by Crumpp (Post 447100)

They restricted its use when full to non-combat flying. It was prohibited to dogfight with a specified amount of fuel in the tank.

That was so the CG would be within specs......

Originally Posted by Crumpp (Post 447105)

Of course....

NA said don't fight the aircraft and use the 25 gallons of fuel in the tank first in an airplane that will burn 26 gallons climbing to 11,000 feet.


Supermarine said, "It is messed up, deal with it by careful flying."

Originally Posted by NZtyphoon (Post 447112)

So, NA can say "We messed up with the new fuel tank, don't try and be a hero flying this aircraft in this configuration" because they are complying with a standard, while Supermarine can point out that in bumpy air there may be problems at high speed because they are not complying with a standard? :rolleyes:

Nor, it seems, were they under any obligation to say anything because they knew about some undetermined problem in 1936 but decided to do nothing because it was going to cost money and it was the designer's fault anyway. :rolleyes::rolleyes: