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Pilot G-limit compared to the Bf 109 and Fw 190


Dirkan

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I thought the Spitfire rudder pedal design had a second set of higher bars above the standard bars for the feet. This raised the legs more when in combat to give better tolerance to G-forces.

 

Talisman

 

Yep, the "two step" rudder pedals were adopted for the Spitfire in early 1940; the upper set were about 6" higher than the original.

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So, if I had things my way, the P-51 would be more powerful than it is now (by being given historically-common G-suit and historically-common higher WEP rating), while the Me 109 would be less powerful than it is now (by the more historically-common G model being chosen instead of the K). That should solve both problems (relative fighting ability, and historical significance) at once.

 

I am not sure Allied jocks would have it easier if we would have a G-14 or a G-14/AS instead of the K, given the prominence of low altitude combat and that the G-14 series are overall a bit better at these altitudes than the current lower-powered K-4 we have, expect in speed perhaps. A bit better climb, actually, and the MG 151/20 on the Gs is probably easier to use for most against fighters.

 

In any case, the 51D was entering combat at about June 1944, before that and after that for a while you mostly had Bs and Cs around; and the K-4 in October/November 1944. There is just a couple of months of introduction between the two.

 

Orly? The angle for both Fw190D and P-51D is almost identical.

 

attachment.php?attachmentid=66977&stc=1&d=1109148210

 

mustang-6.jpg

 

Its not about as much as seat angle, rather than the position of the legs - pedals on the 109/190 are intentionally higher than on the 51.


Edited by Kurfürst

http://www.kurfurst.org - The Messerschmitt Bf 109 Performance Resource Site

 

Vezérünk a bátorság, Kísérőnk a szerencse!

-Motto of the RHAF 101st 'Puma' Home Air Defense Fighter Regiment

The Answer to the Ultimate Question of the K-4, the Universe, and Everything: Powerloading 550 HP / ton, 1593 having been made up to 31th March 1945, 314 K-4s were being operated in frontline service on 31 January 1945.

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I am not sure Allied jocks would have it easier if we would have a G-14 or a G-14/AS instead of the K, given the prominence of low altitude combat and that the G-14 series are overall a bit better at these altitudes than the current lower-powered K-4 we have, expect in speed perhaps. A bit better climb, actually, and the MG 151/20 on the Gs is probably easier to use for most against fighters.

 

I believe the G-14 would be a better competitive match for a 72" P-51D than the K-4 is; at normal combat altitudes, generally speaking, the G-14 would turn & climb better, while the P-51D would be faster. The 109G was also more commonly used than the K, so such a change would also be superior for historical representation. This is all rather moot, of course; the work's already been done, the K-4 being chosen (as I understand it) because reliable data was more readily available.

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The angle for both Fw190D and P-51D is almost identical.

 

When view thru the wishful eye...sure.

 

Look at the location of the rudder pedals, bottom of the seat and angle of the back rest.

 

They are not identical at all.

Answers to most important questions ATC can ask that every pilot should memorize:

 

1. No, I do not have a pen. 2. Indicating 250

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When view thru the wishful eye...sure.

 

Look at the location of the rudder pedals, bottom of the seat and angle of the back rest.

 

They are not identical at all.

 

Yeah, except the rudder pedals on the P51 are also adjustable, and the one in the pic is for the longest legs position.

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Yeah, except the rudder pedals on the P51 are also adjustable, and the one in the pic is for the longest legs position.

 

Meaning that you can adjust them so that a short pilot couldn't reach them or...? I do not so how being adjustable is relevant to g-tolerance. Highmounted pedals/legs are beneficial to g-tolerance, so are laid back seats. It doesn't seem to be the 51 cockpit was designed with that in mind - but late in the war, they did have g-suits to improve upon that.

http://www.kurfurst.org - The Messerschmitt Bf 109 Performance Resource Site

 

Vezérünk a bátorság, Kísérőnk a szerencse!

-Motto of the RHAF 101st 'Puma' Home Air Defense Fighter Regiment

The Answer to the Ultimate Question of the K-4, the Universe, and Everything: Powerloading 550 HP / ton, 1593 having been made up to 31th March 1945, 314 K-4s were being operated in frontline service on 31 January 1945.

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It says, "The seat is adjustable vertically." That means that the seat can move up and down; it doesn't say anything about tilting forward and backward.

 

 

 

Your text says, "The suit was little used by the RAF, partly because [...] aircrew were forbidden to use this secret system over enemy territory."

 

If so, then it makes more sense to model no G-suit in the Spitfire.

 

Please read again. I said fair for the Seafire not Spitfire, LOL. Surely you agree for the Seafire, yes? I did not say fair for the Spitfire, just Seafire.

 

Edit: OK, I now see you re read my post and re posted. Thanks.

 

Talisman


Edited by 56RAF_Talisman

Bell_UH-1 side.png

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Yep, the "two step" rudder pedals were adopted for the Spitfire in early 1940; the upper set were about 6" higher than the original.

 

Yes, I believe the feet/legs being raised up to a higher level towards the level of the pilots backside helps slow down, lessen, the flow of blood away from the brain under positive G-force.

 

I believe that the important thing to remember about g-forces in flight is that it is the "rate of onset" that can be a critical factor. If high g-forces come on gradually, then there is more chance to mitigate against it and stay in control of the aircraft, but very high rates of onset send the pilot to sleep very quickly; this is when the instant effect of the anti-G-suit comes into its own.

 

Happy landings,

 

Talisman

Bell_UH-1 side.png

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Meaning that you can adjust them so that a short pilot couldn't reach them or...? I do not so how being adjustable is relevant to g-tolerance. Highmounted pedals/legs are beneficial to g-tolerance, so are laid back seats. It doesn't seem to be the 51 cockpit was designed with that in mind - but late in the war, they did have g-suits to improve upon that.

When adjusted for short pilot, the tall pilot's legs would have to raise higher to operate the pedals.

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Grapejam says:

Yeah, except the rudder pedals on the P51 are also adjustable, and the one in the pic is for the longest legs position.

 

Adjustment for the length of a pilots legs does not change G-resistance but it sure does make it more comfortable to fly!

 

:smilewink:

Answers to most important questions ATC can ask that every pilot should memorize:

 

1. No, I do not have a pen. 2. Indicating 250

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Grapejam says:

The FW190's pilot seat doesn't look that angled to me:

 

It is better for the G-resistance by a pretty good margin, Grapejam.

 

Granted these are drawings and not 100% accurate but the general idea will hold true.

 

28tklmp.jpg

 

2hg8brp.jpg

 

Now, the upright seating of the Spitfire and P-51 is a lot more comfortable.

 

That comfort makes a huge difference when you have fly 3 hours before engaging the enemy.

Answers to most important questions ATC can ask that every pilot should memorize:

 

1. No, I do not have a pen. 2. Indicating 250

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I'm gonna start a petition for Bader-isation of all Fighter Command pilots to try and compensate for this design shortcoming of the human body!

 

It will be a simple field modification to the pilot. Chloroform and a hacksaw is all thats needed.

 

I actually love the idea of realistically different G limits for different aircraft. It adds another dynamic to combat.

 

:thumbup:

Answers to most important questions ATC can ask that every pilot should memorize:

 

1. No, I do not have a pen. 2. Indicating 250

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It is better for the G-resistance by a pretty good margin, Grapejam.

 

Granted these are drawings and not 100% accurate but the general idea will hold true.

 

28tklmp.jpg

 

2hg8brp.jpg

 

Now, the upright seating of the Spitfire and P-51 is a lot more comfortable.

 

That comfort makes a huge difference when you have fly 3 hours before engaging the enemy.

 

Yep, nevermind that in the pic, the 190's pilot's back was lying against the seatback, while the P51's pilot was not, why didn't you draw the line according to the seat's angle and not the illustrated pilot's back angle?

 

Also why did you have to use the P51B's, we have the D model in the game.

 

VcsA7Q6.jpg

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Grapejam says:

why didn't you draw the line according to the seat's angle and not the illustrated pilot's back angle?

 

Cause it does not make any difference Grapejam? You can take it personally and hate me but it is just a fact the pilot seating is more advantageous for G-tolerance in the FW-190 series than the P-51.

 

:smilewink:

Answers to most important questions ATC can ask that every pilot should memorize:

 

1. No, I do not have a pen. 2. Indicating 250

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Cause it does not make any difference Grapejam? You can take it personally and hate me but it is just a fact the pilot seating is more advantageous for G-tolerance in the FW-190 series than the P-51.

 

:smilewink:

Such difference, much advantageous :rolleyes::

mPgcr26.jpg

 

Oh btw there's still quite a bit of room left for the P51 pilot to adjust his seath downward, thus raise his leg up even higher.


Edited by GrapeJam
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You proved it!!

 

:thumbup:

 

Seriously, not even going to explain how silly this is becoming. You drew your line on the side of the seat...not the back. Just look at the axis from the heart to the brain....

 

Just go sit in an FW-190 cockpit and then a P-51. You will notice a big difference.

Answers to most important questions ATC can ask that every pilot should memorize:

 

1. No, I do not have a pen. 2. Indicating 250

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I'd jump in a FW190 or P51 like a shot if I had easy access to em ;)

 

All I've managed is a Spit XVIII and English Electric Lightning.

 

The spit isn't actually bolt upright as many assume. Though because the owner was rather short the pedals were so far back my knees were around my ears the top bar of the pedals was roughly level with the seat base.

 

I wonder if ED could share their data on how they figure out the differences in G tolerance. Would be interesting!

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You proved it!!

 

:thumbup:

 

Do you actually think that the the G limit increase is a linear gradient curve as the pilot's head position angle to the back? :megalol:

 

New flash for your, it's not, the blood becomes significantly harder to drain from the head when the head's position is lower than the legs, much harder when the head's position is above.

 

Seriously, not even going to explain how silly this is becoming. You drew your line on the side of the seat...not the back. Just look at the axis from the heart to the brain....

 

Just go sit in an FW-190 cockpit and then a P-51. You will notice a big difference.

 

Because the P51's pilot can't lean his head against the seat like the 190's pilot. :doh:

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GrapeJam

 

Maybe you missed what I wrote or it did not sink in on your P-51 comparison?

 

Crumpp says:

You drew your line on the side of the seat...not the back.

Answers to most important questions ATC can ask that every pilot should memorize:

 

1. No, I do not have a pen. 2. Indicating 250

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Maybe you missed what I wrote or it did not sink in on your P-51 comparison?

why should I draw the line according to the pilot's back instead of the seat? Is there only 1 sitting position human can do?

 

Oh BTW, if you wanna talk parachute, the chute's placement is below the pilot's bum, not on the pilot's back.

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I'm going to end this rubbish.

 

The G effect from the incline in these WW2 fighters is infinitesimal. The Incline in F-16 was only about 1G, so no 109 or 190 is going to be getting 1.5 or even 2 G out of this. Crumpp, it is hard to believe you don't know this.

 

But lets cease with the angle mongering and just cut to the actual date:

 

file.php?id=2308&sid=7f3802818adfa7cd12c31da78cfbf5be&mode=view

 

I measured the inclines of the two seats, and in the 190 you have about 20 degrees to the P-51s 14 degrees. Pilot posture would alter this in meaningless ways. At 20 degrees, you brain blood pressure would be so low as to make no meaningful difference in G tolerance.

 

"In a study in which 250 centrifuge runs were made on human volunteers, it was demonstrated that systolic blood pressure in the radial artery held at eye level was reduced by 32 mm of mercury for every G added to the ± G2 force. Visual disturbances occurred when the systolic blood pres- sure at the base of the brain was reduced to 50 mm of mercury and complete loss of vision occurred when the pressure was reduced to 20 mm of mercury. Loss of consciousness occurred when the systolic pressure at brain level was reduced to zero. This would be equivalent to a five ± G pull, i.e., 5 x 32 = 160, where the blood pressure at the base of the brain would be reduced to zero if the systolic blood pressure in the subject was 160 at the heart level."--historic.aerobatics.org Eoin Harvy, MD.

 

Complete loss of vision occurs at a brain BP of 20. COMPLETE LOSS. So you would need at least 35 degree, double what is shown here, to get even a single solitary G of tolerance.....and you would be on the very edge of a complete blackout. So no, you are not going to get 1.5 to 2G of tolerance from this. And in order to pull the 6.5 to 7 G posted earlier, you would need to have a angle of 45 degrees....


Edited by ArkRoyal
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A very good post Arkroyal. So why the huge difference between the blackout limits in the different modules?

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