[CLOSED] wings break off at 4g

[Crumpp]

That said, this is the 109 section, lets stay on topic.

 

oops! Sorry!

[Solty]

I stand corrected, the POH limit is 8G's at 8000lbs.

 

Weight adjust the limit accordingly.

 

P-51D clean configuration fighter with pilot = 9478lbs equals a 6.75 G limit.

 

I missed the note on 8 G's in the manual.

 

Unfortunately none of the airplane limits trump the pilots....

 

But... You have to take the safety factor 1.5. So 6.75 x 1.5 so that equals 10,1G:huh: Which prooves that wings should break at ultimate 10G+

 

oops! Sorry!

Yes we will move to PM next time.:thumbup:

Edited January 13, 2015 by Solty

[Crumpp]

Which prooves that wings should break at ultimate 10G+

 

Not if the load is asymmetrical or you subjected the airframe to any load factor. That is a one time single axis load on a perfect airframe. That applies to all aircraft. PM sent so we can discuss the specifics of the P-51.

Edited January 13, 2015 by Crumpp

[NineLine]

But... You have to take the safety factor 1.5. So 6.75 x 1.5 so that equals 10,1G:huh: Which prooves that wings should break at ultimate 10G+

 

 

Yes we will move to PM next time.:thumbup:

 

DOnt need to move to PM, if you think there is an issue with the P-51, you need only make a thread in that section of the forum.

[Crumpp]

Will Do!

 

Just making sure we have a potential "real" bug. Solty is running some test's ensuring the aircraft is co-ordinated flight with a single axis load on recovery along with some tracks.

 

If we find an issue, we will post the tracks and aircraft data in the bug section so Yo-Yo et all can see the sources being used to compare with what's in the game.

 

Like I said earlier, every wing failure I have had in the game has been my fault.

[IvanK]

Suggesting pilot blackout at 4.8G is ludicrous. The table shown is for an average relaxed individual .... like a dopey passenger sitting in your backseat maybe. A pilot going into combat is not exactly in a relaxed state. And once the G comes on he will be working his best straining manoeuvre ... yes even in WWII. I have spent a fair portion of life pulling G in fighters (Mirage III and F18 albeit with a G suit) so have a fair impression on G and its effects. now as a 58 year old of average fitness I am regularly pulling up to 6G without a G suit and don't suffer ANY g induced issues. Sure it varies from person to person but suggesting blackout at 4.8G for a fighter pilot is nonsense.

[NineLine]

Suggesting pilot blackout at 4.8G is ludicrous. The table shown is for an average relaxed individual .... like a dopey passenger sitting in your backseat maybe. A pilot going into combat is not exactly in a relaxed state. And once the G comes on he will be working his best straining manoeuvre ... yes even in WWII. I have spent a fair portion of life pulling G in fighters (Mirage III and F18 albeit with a G suit) so have a fair impression on G and its effects. now as a 58 year old of average fitness I am regularly pulling up to 6G without a G suit and don't suffer ANY g induced issues. Sure it varies from person to person but suggesting blackout at 4.8G for a fighter pilot is nonsense.

 

I read about the testing of the Franks G-suit, a person not wearing the test G-suit was experiencing the "onset of black-out" during manoeuvres of 6.2G and 7.7G. Now I think these were test pilots, so maybe their tolerance was better than most, bur regardless, it does show that a pilot even then could handle more than 4.8G without a G-suit.

[Crumpp]

I read about the testing of the Franks G-suit, a person not wearing the test G-suit was experiencing the "onset of black-out" during manoeuvres of 6.2G and 7.7G. Now I think these were test pilots, so maybe their tolerance was better than most, bur regardless, it does show that a pilot even then could handle more than 4.8G without a G-suit.

 

 

The 4.8G is a mean.

 

I would rely on measured data and not anecdotes. Denial is one of the symptoms pilots experience under high accelerations. Should not be a surprise, the brain is essentially hypoxic as the blood flow is impaired.

 

The most important of the observed symptoms of G-LOC are amnesia, impaired motor coordination, confusion, disorientation and denial. In fact, amnesia (loss of memory for the event) and denial reduce the number of reported G-LOC incidences, in turn artificially reducing the perception of the hazard. Impaired motor coordination and mental confusion extend the length of recovery and therefore tend to increase the hazard of G-LOC and likely consequences as per the attitude or altitude of the aircraft.

 

http://www.avmed.in/2012/06/g-loc-demystified/

 

 

IvanK says:

A pilot going into combat is not exactly in a relaxed state.

 

Exactly. Stress tends to lower G tolerance making GLOC more likely.

 

Why do you think a mean 4.8G is ludicrous? Is there an issue with the scientist, engineers, and aviation organizations that went out and collected the facts and you see they missed something?

[IvanK]

Scientists can produce all sorts of fancy graphs and data. However a 4.8G LOC value just doesn't gel with the real life fighter pilot experience or for that matter basic aerobatic pilot experience. Go out and talk to Fighter pilots or even basic aerobatic pilots ask them if they black out at 4.8G.... I bet you don't find to many. .... and I am only talking about Blackout let alone LOC.

 

As to stress causing a reduction in G tolerance ... what sort of stress ? Being tired is stress, Feeling crook after a night on the turps is stress these types of stress would I agree reduce G tolerance. However being head of your game adrenaline up as you approach the merge is stress ... this kind of stress increases your G tolerance (real world demonstrated fact). Doing your best Anti G straining manoeuvre is also stress ... that increases your G tolerance !

 

So practical pilot experience in real world situations demonstrates unequivocally that few (if any) fighter pilots succumb at 4.8G. You can choose to believe all your stats and data, I believe what I have seen and done on a daily basis for a large portion of my life.

[NineLine]

The 4.8G is a mean.

 

I would rely on measured data and not anecdotes. Denial is one of the symptoms pilots experience under high accelerations. Should not be a surprise, the brain is essentially hypoxic as the blood flow is impaired.

 

I think an anecdote is pretty good if it was from a flight where the goal was to test the effectiveness of G's on a person wearing a G suit. Test data can be a poor info as well, if you dont know all the conditions it was collected in, regardless of all this chest puffing, ED has to take all this info and process it and decide what is best.

 

Lets try a new approach, if you have information, feel free to post it, but let ED decide what is good and what isnt, we dont need to pick apart each others info.

 

This is reported and its being worked on.

[Crumpp]

More facts:

 

Note that at an onset rate of lG per second, the G values in Table 1

could just as well be expressed in seconds. Thus, the "average" pilot

accelerating at IG per second could expect to have grayout at 4.1 seconds,

blackout at 4.7 seconds, and unconsciousness at 5.4 seconds.

 

http://www.skybrary.aero/bookshelf/books/2758.pdf

 

Aggressive dive-bombing techniques that were developed during the 1930s produced severe acceleration during the pull-up at the end of the bombing run.4 Sporadic reports began to appear of blackout during these maneuvers as well as concern about acceleration-induced loss of consciousness (G-LOC). These problems were correctly attributed to “cerebral anemia produced by centrifugal action,” and the Royal Air Force determined that 4 G (acceleration 4-fold greater than the force of gravity) was the limit of human acceleration tolerance.5

 

https://ke.army.mil/bordeninstitute/published_volumes/harshEnv2/HE2ch33.pdf

 

Studies performed in the 1940’s and 1950’s by the U.S. DoD found that without any strain or G-suit, average G’s prior to G-LOC was dependent on the rate of G onset. G-LOC occurred at an average of 5.4 G’s at 1 G/sec rate and 4.5 G’s at 2 G/sec rate.

 

http://goflightmedicine.com/pulling-gs/

[MiloMorai]

However do those aerobatic pilots do it?

 

Matthias said that we were pulling a face distorting 6.5 Gs at the bottom: that’s the equivalent of having a 66-stone man sitting on your head.

 

How many Gs have you pulled in your Extra Crumpp?

[Crumpp]

How many Gs have you pulled in your Extra Crumpp?

 

It did not pass a pre-buy so I did not get it.

 

My airplane already is aerobatic....you do know that?

 

 

 

 

 

How many G's have you pulled as PIC? Come on and share.....

[NineLine]

Guys, keep the discussion on the 40's.

[Cedaway]

All depend the duration...

I sustained 6G manoeuvers in a Marchetti SF-260 many times without any problem but I nearly G-LOC'ed at 4,5G in a Fouga Magister during a "clover leaf" that lasts forever.

[Kwiatek]

Blackout at 4.8 G is too low. Maby it could happend with some people but most could stand it without blackout. I got sometimes passengers in aerobatic ZLin and they could stand 5 G without any blackout symptoms.

 

I could stand 5-6 G also with no problems.

 

So for a fighter pilot 4.8 G is nothing special. I think prolonged 6 G could make a difference.

[sobek]

The DCS model has a "memory", just as in RL, preparation and the onset speed of Gs are taken into account and have a great impact on how many and how long the pilot can endure the increased force. Have any of you ever done a proper preparation routine before pulling Gs?

[BKZerg]

The quote from the manual. Page 112.

 

The structural load limit for the Bf 109 K-4 is roughly wintin +8G and -4G. However no cockpit G-force indication is provided, and light construction combined with large control forces required to pilot the aircraft at higher speeds generally mean that overloading the airframe is unlikely under most conditions.

 

 

Thus I consider that at first should be the blackout, and after, if pilot continue pull the stick, wing-off. However i have no black, so glue my wing back.

[Crumpp]

The DCS model has a "memory", just as in RL, preparation and the onset speed of Gs are taken into account and have a great impact on how many and how long the pilot can endure the increased force.

 

 

That is good. However, the model seems to be tailored for a modern fighter pilot.

 

You can pull 8-9 G to get wings off without any physiological effects on the pilot.

 

A 7-8 G threshold studies show is the realm of G suits and proper AGSM.

 

G-suits and AGSM have a huge effect on G-tolerance. The vast majority of fighter pilots in World War II had neither one. If we discard all experiments and go with only what made it into operational service, only one Air Force fielded a G-suit the last year of the war.

 

A G-suit raises the onset rate which has a direct effect on tolerance by 3.4 times normal. The suit also decreases the severity of symptoms of exposure to accelerations.

 

The episodes of G-LOC associated with wearing an anti-G suit were compared with the G-LOC episodes where an anti-G suit was not worn, as shown in Table 12. Anti-G suit wear was associated with an increased GMAX and GLOC. The ONRATE associated with anti-G suit wear was much more rapid (2.4 G/s) than the ONRATE where an anti-G suit was not worn (0.7 G/s). The incapacitation associated with G-LOC episodes where an anti-G suit was worn was decreased compared to the G-LOC episodes where the anti-G suit was not worn. This demonstrates a valuable, but previously unknown, facet of the protection provided by anti-G suits.

 

Here we can see the results of a US Navy study reviewing 500 episodes of GLOC.

 

 

 

Here is the effect of AGSM:

 

[/url]

 

Our average GLOC threshold goes from 7.9G's to 5.7G's due to the effects of wearing a G suit and AGSM.

 

I do not know or pretend to know the mechanics of the DCS model.

 

In basic form a realistic model could be done based on systolic blood pressure. That is the mechanism in the human body that causes all the symptoms.

 

The heart can only produce so much pressure to push a column of blood the average distance of 36cm to the brain.

 

Modifiers to that basic relationship have been developed for G-suits and AGSM. The basic formula could easily be modified for seating position thru Z axis vector resolution. It is the Z axis exposure than matters to the human body as a fighter pilot.

 

The various symptoms of G exposure all have an average pressure which they occur at a total G exposure based on onset rate and exposure time.

[Crumpp]

The structural load limit for the Bf 109 K-4 is roughly wintin +8G and -4G.

 

The Germans used a higher engineering safety factor. The full report is attached in this thread.

 

Here is a table illustrating the difference.

Edited January 18, 2015 by Crumpp

[sobek]

That is good. However, the model seems to be tailored for a modern fighter pilot.

 

You can pull 8-9 G to get wings off without any physiological effects on the pilot.

 

The model does take the existance of a g-suit into account. If you use your full instantaneous pitch rate, of course your wings will snap off before you notice the onset of loss of color vision, because it takes some time for the oxygen in the tissue to be depleted.

[Crumpp]

The model does take the existance of a g-suit into account.

 

Which the vast majority of World War II fighter pilots did not use. That parameter should be removed for the ones that did not field a G-suit. That G-suit was not as effective as a modern one either so there is some leeway in adjusting the advantage. Seating position can be accounted for with simple vector resolution on the Z-axis. Some historical advantage is more realistic than none.

 

I am willing to bet DCS already has a solid foundation that just needs to be tweaked for World War II designs to account for the fact G-tolerance effects on pilot physiology research was still in its infancy. Not looking for perfection either....just representation.

 

I think it is important to model what we can to give us feedback on the state of the aircraft. We do not have a butt to seat interface in DCS and there is the only way to model one. The pilot in World War was much more limiting than the aircraft.

 

Pilot physiology modeled for the time period will help make the game more fun and fights more competitive. Lots of G-exposure symptoms do not result in catastrophic incapacitation but they do give you a clue where you are at in the exposure envelope.

 

If you use your full instantaneous pitch rate,

 

 

Keep in mind, the more rapid the onset rate, the less resistance we have to it. Meaning we get no warning, just lights out.

 

A modern G-suit provides ~3.4 times the resistance to onset rate over not having one.

 

Our modern fighter pilot with a G-suit would be unaffected whereas our World War II pilot would not be so lucky.

 

When you get down to it, a World War II pilot's flying gear was pretty spartan compared with a modern fighter pilot.

 

In World War II they did this stuff with pretty much a leather jacket and a nice watch.

 

:smartass:

 

They were a lot cooler than today's jet jockey's. :pilotfly:

[sobek]

Which the vast majority of World War II fighter pilots did not use.

 

Which is taken into account.

 

Keep in mind, the more rapid the onset rate, the less resistance we have to it. Meaning we get no warning, just lights out.

 

Wrong, there is a certain amount of useful time of consciousness even if your jugulars are cut. This is hypoxia induced LOC, not somebody hitting you over the head. As i said, the oxygen concentration in the tissue provides a buffer before hypoxia fully sets in, certainly enough to rip your wings if you try to.

Edited January 27, 2015 by sobek

[BKZerg]

Except the moment of blackout (with g-suite or without it), it would be desirable to know, whether the pilot will be able physically to pull the handle to create the overload sufficient for collapse of the plane?

 

My pilot is Terminator`s brother? Does he have unlimited hands force?

 

 

Lower on the same page of manual (p112):

Undue stress on the airframe is generally only possible when pulling out of a high-speed dive.

Not using full stick deflection during dive pull-out is generally the only precaution needed to avoid overstressing the airframe.

 

So why when i`m pulling stick at half or even at quarter of it range even in horisontal turn at ~400 km/h i have my wing off?

Edited January 18, 2015 by =BK=Zerg

[Crumpp]

Wrong, there is a certain amount of useful time of consciousness even if your jugulars are cut.

 

Yes there is but you are not going to safely recover an aircraft in a steep dive at 500 mph in 6 seconds.

 

Your choices are pretty much to reduce the load factor and lengthen the recovery time or snap the wings or go to sleep.

 

That is the danger of Rapid Onset Rate (RoR) because it goes straight to GLOC without any other symptoms. That is the result of the human bodies lower resistance to RoR.

 

.7G/s per second is a much lower rapid onset rate threshold than 2.4G/s.

 

 

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Which is taken into account

 

Are the pilots wearing a G suit or not? Your reply is confusing.

 

The model does take the existance of a g-suit into account.

 

Here it looks like you are saying the physiology model does not have a G suit whereas your previous reply says they DO HAVE a G-suit. It does not really matter though.

 

Sithspawn already said the model will be looked at and asked for data. The devs have been very devoted to measured facts and not opinion. That is why I posted more data, it is not a continuation of a complaint but rather fulfillment of the request for more facts.

 

I am sure they will get to it and determine what needs to happen. The world is not going to stop because of this issue.