A newbies impression of the 109 and spit

[VO101_Tom]

Originally Posted by Glider

Just an observation, but the RAF never needed to develop a two seat Spit or Hurricane and trained many thousands of pilots to fly them. But the Luftwaffe needed to develop two seat 109's with the inevitable distruption on the design and production teams, presumably because they needed to.

Hi. Only about ~100 aircraft were modified to G-12 standards (it was conversion only, G-2, G-3, G-4, G-6 types). I think these aircrafts used more for combat training, not for the basic exercises, circuits. For example, the RHAF did not use the G-12 type (Hungary also produced 109 G-6, G-8, G-14 types). If this was really necessary, then they would have converted.

[VO101_Tom]

Originally Posted by Crumpp

You guys read a few anecdotes from a very small group who gambled and won. You don't get the wartime feedback from the 85% who lost because they are not around to tell you, "Hey, that did not work like I thought it would."

Yep, this is why i hate the war stories as technical or performance "evidence". Interesting stories, but nothing more Best example is the maneuverability. Both sides said they're all turned better than the other side. Ok, but what were the circumstances of the situation? That is very little read, and one of the most important thing in the pre-battle situation.

[bongodriver]

And what are doing in spin recovery?

Not pulling out of a Vne dive thats for sure, if you think spitfires all broke up in post spin dives then every one of them would have crashed.

absolutely nothing you have written here applies specifically to the Spit, you cling on to the obscure certification entry about 'no intentional spins' which if you know anything you will accept it can be down to factors I described earlier.

A load factor of 2.5 G's......wow massive, the Spit airframe could stand 10 G's, serously find a official source for claims spitfires 'broke up' post spin.

[Crumpp]

No...it seems to just show some FAR's for certification in the US, much like American light aircraft certificates show UK/European requirements

It is a fact all convention signers follow the same rules, principles, and procedure for aircraft airworthiness.

That is why we all use the same regulations and quote them.

Here is a quick highlight of the worlds aviation conventions. The only thing state and military aircraft are exempt from is the navigation rules.

They still must abide by the convention airworthiness standards.

October 1919 , Paris : Convention Relating to the regulation of Air navigation

Sovereignity over Airspace.

Standard for airworthiness

Certificates of competency for crews

Definition of aircraft

http://www.fabioaddeo.com/2011/02/26...nd-agreements/

[Crumpp]

A load factor of 2.5 G's......wow massive, the Spit airframe could stand 10 G's

10G's asymmetrically? You think?

[bongodriver]

Originally Posted by Crumpp

10G's asymmetrically? You think?

Yup

[bongodriver]

I can't be bothered to wait for you to browse wiki or scour the internet for other obscure stuff....

You don't really seem to even know what asymetrical g load is, remember that thread about roll rate at high speed? well......diving a spit to 400 mph and applying max stick roll force.....thats aymetrical loading my friend.....I don't seem to recall wings peeling off in those tests, if it could take those asymetrical loads then there is no way in hell it will break up in spin recovery no matter how sensitve the elevator is or how staticaly neutral it is.

[Crumpp]

Yup

Well you are dead wrong bongodriver.

First of all the 10G's is to the failure point. It is 10G's on a single axis and assumes a perfect airframe. That 10 G's represents a 100% chance the airframe will be permanently deformed and we run a good chance of having the airplane turn to confetti. This is why the POH warns the airframe will certainly fail if this limit is much exceeded.

Our we run the risk of damage threshold is lower than that at 6G's.

That too, is 6G's on one axis with a perfect airframe.

Just like your car suspension wears, so does an airframe. It is not the spars or major structures that fail first, it is the ribs, skin, and supporting structures. An airframe flexes in flight, even at 1G. Gusting, accelerations, and turbulence all add wear to the airframe and lower those limits. It is just like your cars suspension wears from driving all the bumps it has to absorb.

Asymmetrical loading significantly reduces the airframe limitations. The average is about 20%. So our 6G damage limit is now 4G's with an asymmetrical loading.

Our normal spin recovery AVERAGES about 2.5G's so on AVERAGE we could spin a Spitfire safely as long as the pilot correctly and precisely applied the control inputs.

But wait, he has a very hard time being precise with control inputs especially when he is subjected to the same accelerations. Oh yeah, when he steps on the rudder, it also produces even more acceleration on the longitudinal axis adding to his difficulty.

He has 1.5G's to play with before he can damage the airframe. The airframe is now weaker and will fail at a lower point.

Now let's add in the vertical load from gusting...Oh crap we are at the threshold in light turbulence!! The POH also warns of this! Coincidence?

You botch the recovery, damage the airframe, and it re-enters the spin, as the POH once again warns the pilot about. Why can you re-enter a spin so quickly and must build up your speed? In any airplane if you don't have enough speed you can re-enter the spin. In the Spitfire is especially important. The pilot needs that speed to have better precision on the controls. He only has 3/4 of an inch of stick travel to use up all of this angle of attack at 5lbs per G. The heavier he can make that stick, the more precise he can be in controlling the acelerations. If he re-enters the spin with a damaged airframe his chances are even less of coming home.

Now do you see why spins are prohibited in the Spitfire? The average time you spin the airplane, it will come out "just fine". The margins between "just fine" and disaster are tighter than you think.

If the pilot could precisely control the accelerations and did not have the yaw-wise pitch up, it would be a much safer aircraft to spin.

[Crumpp]

diving a spit to 400 mph and applying max stick roll force

What is a max stick force roll at that speed? Don't confuse stick forces and control surface deflection.

You realize that 400 mph is well over Va so full control deflection will exceed the airframe limits on just one axis......

Think about what you are saying in this claim.

[robtek]

I think the point is, that in a spit, during a stall-recovery, it is extraordinarily easy to exceed the stick movement necessary to overload the airframe.

Much more easy as in the comparable planes, which needed more stick-travel and force.