Stability and Control characteristics of the Early Mark Spitfires

[Crumpp]

documentary evidence to prove his cock-eyed theories on 100 octane I

You mean like the fact it is not the specified fuel in the portion of the Operating Notes entitled "Notes on a Merlin Engine" is a strong indicator the fuel is still undergoing service testing?

I never disputed the fuels use, just the silly notion it was the only fuel available and the adopted service fuel.

Who would ever suggest they were still undergoing 100 Octane fuel testing in August of 1940 simply on the basis the facts do not align?



100 Octane is completely off topic. Start your own thread if you want to debate it.

[41Sqn_Banks]

Originally Posted by Crumpp

The never changed it because a high speed dive is generally the result of spin recovery and a Spitfire pilot could break the airplane rather easily.

Honestly I always thought a high speed dive is the typically the result of a prolonged dive. Is diving also prohibited?

[Crumpp]

NzTyphoon,

It is not my theory nor is that one report the basis of the conclusion the United Kingdom aviation authority did not have stabilit and control standards.

Simply post the ARC standards used during the war. They will be written in a simliar fashion to EVERY other stability and control standard in the world.

They will define the acceptable qualities in an airplane.

Just like the NACA did!!

Here is the link to the UK ARC reports:

http://aerade.cranfield.ac.uk/listarcrm.php

[Crumpp]

Honestly I always thought a high speed dive is the typically the result of a prolonged dive. Is diving also prohibited?

What does a deliberate dive have to do with a spin?

In spin recovery with longitudinal instability, if the airplane is below Va, the risk of secondary stall is greatly increased.

Above Va, the risk of airframe destruction is greatly increased.

Understand?

[41Sqn_Banks]

Originally Posted by Crumpp

What does a deliberate dive have to do with a spin?

In spin recovery with longitudinal instability, if the airplane is below Va, the risk of secondary stall is greatly increased.

Above Va, the risk of airframe destruction is greatly increased.

Understand?

The pull up during spin recovery above Va has increased risk of airframe destruction.
The pull up during dive recovery above Va has increased risk of airframe destruction as well.

Why is one prohibited and the other not?

[BTB]

http://it.scribd.com/doc/4598146/Pil...lin-XII-Engine

[robtek]

Probably because a controled dive with a defined level out altitude is different from a spin with a uncontroled loss of altitude and therefore the possible increased urgency to level out before hitting the ground.

[Crumpp]

Why is one prohibited and the other not?

See robtek's post, 41 Banks.

Exactly, in a normal dive, it would be very unusual for the pilot to be "behind the airplane". In an accidental spin, it is very likely the pilot will be "behind the airplane".

Goes back to aviation axiom, "Never Let an Airplane take you someplace your brain did not get to at least 5 minutes before."

Right BTB,

If you read the spin recovery procedures in the Operating Notes, it instructs the pilot to make a prolonged dive.

With the longitudinal instability, the aircraft would require more more velocity to buffer against over controlling the recovery and inducing a secondary stall.

In otherwords, the low stick forces and large elevator changes for very small stick inputs make the aircraft vulnerable to secondary stalling in a normal spin recovery sequence.

The high dive speed required to recover from a spin also make the aircraft vulnerable to exceeding the airframe limits by overcontrolling.

I would not be surprised to discover the Spitfire Mk I was cleared to spin after being fitted with an inertial elevator to correct the longitudinal instability.

[41Sqn_Banks]

Originally Posted by robtek

Probably because a controled dive with a defined level out altitude is different from a spin with a uncontroled loss of altitude and therefore the possible increased urgency to level out before hitting the ground.

Indeed, spinning is one of the most dangerous man oeuvres. Combined with the fact that there is little to no benefit from a deliberate spin it's the simplest solution to prohibit it.

Btw I don't get why topic has so many pages. Just read the Pilot's Notes, it's all there:

- exceptional/remarkable light elevator response even at high speed, which is a good thing and a bad thing (risk of high speed stall and blackout/break up the aircraft if pilot is not carefully)
- instability in turns (elevator becomes lighter in turn)
- stall warning/buffeting/buzz (best turn rate is achieved slightly before buffeting)

Now let's look at the current FM and find out if this is represented.

[winny]

I see you're still using the MK V as your data source for a Mk I/II.

Lmao.

Anyway, this thread is supposed to be about early mark spitfires.
Can I please see some data for a MK I or II?

I'm bored by all this Mk V stuff. It's irrelevant to CLoD.

It doesn't matter what was prohibited and what wasn't. For every single time Crumpp has said that the pilot's notes forbid something I have been able to find a combat report or pilot account where the same manouvers were done deliberately by a pilot. Brian lane deliberately entered spins, deliberately stalled etc etc.

Here we go again with the pilots notes red herring..

Pilots notes are just someone's opinion. They are not proof that prohibited manouvers were never performed. They are just a set of reccomendations. Good pilot's overcame their machines limitations on both sides.