What is "aircraft stability" - IN VIDEO

[JtD]

Originally Posted by Crumpp

The post you quote is a reply to Glider when he made a claim that the norm for fighters in WWII was to have unacceptable stability and control characteristics.

No, that is not true.

Originally Posted by Glider

Can you name any aircraft, of any type, in any airforce, that was hands free during WW2, ie wouldn't eventually destroy itself without pilot input in conditions it was divergent?

and

Originally Posted by Glider

If the Spit is an unusual example, then he should be able to nominate one that was hands free.

Your answer was the linked list. It is not possible to determine that a reply to a quoted question is actually just a list with random planes that in no way relate to the question as asked, which is what you are claiming now.

So to be clear - are you now saying that none of the planes on that list were hands off aircraft and this is a misunderstanding? Or are you going to provide evidence as you claim to provide for all your statements?

[Crumpp]

JtD,

There is no such thing as a "hands off aircraft". There is such a thing as a speed stable aircraft.

All of the aircraft in that list were speed stable.

That means they all moved to trim speed and stayed there unless acted upon by an outside force. The airplane does not care about its relationship to the horizon, altitude, or where the pilots hands are at. It cares about the relative wind and the dynamic pressure. A speed stable aircraft will maintain its orientation to the relative wind and keep the dynamic pressure constant.

This is not something the early Mark Spitfires did. If you look at the stability characteristics as measured by the RAE and the NACA, the Spitfire INCREASED speed away from trim.

Each oscillation, the speed would increase or stay the same where neutral stability existed.

That is a fact. There is no putting on rose colored glasses or claims of "it was normal for an aircraft".

The Spitfire was outstanding in its early instability. That is why they fixed it with the addition of an inertial elevator.

It was not because it was normal, or good, or super maneuverable. It was because it had some dangerous characteristics and made the aircraft more difficult to precisely control for the average pilot.

End of story.

[bongodriver]

Originally Posted by Crumpp

JtD,

It was not because it was normal, or good, or super maneuverable. It was because it had some dangerous characteristics and made the aircraft more difficult to precisely control for the average pilot.

End of story.

It was not dangerous, most of fighter command at the time were average to below average in terms of skills, thankfully the Spit was eay to fly in combat due to its high manouverability and controllability.....end of story

[TomcatViP]

Well... end of ea new story. Never heard that on the BoB era Spits.

Instead I hve read plenty of desciption of frightened young pilot force to go to batthle with under 10 hours on the type.

Never read such thing on the hurri.

[Crumpp]

“Last Witness” Bob Doe explains: “An average pilot could get more from a Hurricane than from a Spitfire. But if you were good you could get more from a Spitfire. A Hurricane was like a brick-built s---house. It was sturdy and reliable, and it did not leap about when the guns were fired.

Whereas the Spitfire was a musician’s aeroplane, a dream, the Hurricane was a very efficient workman’s tool.

http://www.telegraph.co.uk/history/b...been-lost.html





You can see how precisely the pilot is able to hold a given acceleration and how smoothly the airspeed drops in the rapid turn measurements from the NACA.



It is little wonder why the Hurricane accounted for the loin's share of German fighters.

[JtD]

The Hurricane would not move to trim speed and stay there, it would drop a wing and dive into the ground, at an ever increasing speed. It was unstable in the spiral and phugoid modes and much worse at that than the Spitfire, which did at least a few oscillations before departing for good.
The static stability chart you posted is not at all related to phugoid or spiral modes.

[Crumpp]

Hurricane would not move to trim speed and stay there

Yes, a stable airplane will move to trim speed.

If it is statically stable it will move towards trim speed when disturbed.

If it is dynamically stable it will reduce the amount of speed it overshoots trim speed with every oscillation.

The oscillations will grow smaller with each cycle until they are dampened and disappear.

Just like what happens with the Spitfire's stability in Cliff's of Dover....