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That display shows nothing of what is being talked about.

 

+1

these manouvers are tight turns that are to be expected from a spitfire. have seen this myself a couple of times, but have nothing in common with what we are talking about.


Edited by birdstrike
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Yet the owner of Eagle Dynamics owns and flies Spitfires on a regular basis ;)

 

i know, and i dont discredit this guy at all...i said it previously, and am glad to do it again, that i have the highest respect for this man. still it doesnt mean that everything is spot on in dcs. but yeah, im glad that this guy took the lead at ED.

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+1

these manouvers are tight turns that are to be expected from a spitfire. have seen this myself a couple of times, but have nothing in common with what we are talking about.

 

 

Then the onous is on you both to post videos and/or a track file to demonstrate the behavior; I have flown online with and against a number of squad-mates in Spits/109s and can't recall a single occasion when any of us observed any UFO-like behavior unless someone had serious connection issues, in which case that's entirely network related and nothing to do with FM.

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Then the onous is on you both to post videos and/or a track file to demonstrate the behavior; I have flown online with and against a number of squad-mates in Spits/109s and can't recall a single occasion when any of us observed any UFO-like behavior unless someone had serious connection issues, in which case that's entirely network related and nothing to do with FM.

 

Yes, please. If you ever see anything 'UFO' like, create a thread and post the track and conditions, etc in the bug section.

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Every sime I've ever been in I've seen this same dsicussion.

The spitfire being obnoxiously good at turning . . .

 

 

Once, in another sim, we decided to put this to the test.

The Sptfire 1a turned thourgh 360 degrees at it's max turn rate, in 19 seconds

The 109E variant, did the same turn at its max turn rate in 21 seconds.

This matched up almost perfectly with real world data for these types.

 

 

It's relatively easy to test this stuff.. . . .

Unfortunately, I don't own any german modules in DCS, so I cannot conduct a comprehsive test myself.

I can certainly test the Spitfire at a given altitude and airspeed though, and time the 360 turn.

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Watch this, first attempt, just now:

 

It looks like I KNOW what I'm talking about..

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Every sime I've ever been in I've seen this same dsicussion.

The spitfire being obnoxiously good at turning . . .

 

 

Once, in another sim, we decided to put this to the test.

The Sptfire 1a turned thourgh 360 degrees at it's max turn rate, in 19 seconds

The 109E variant, did the same turn at its max turn rate in 21 seconds.

This matched up almost perfectly with real world data for these types.

 

 

It's relatively easy to test this stuff.. . . .

Unfortunately, I don't own any german modules in DCS, so I cannot conduct a comprehsive test myself.

I can certainly test the Spitfire at a given altitude and airspeed though, and time the 360 turn.

 

nobody complains about the continuous turn rate of the spit.

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Watch this, first attempt, just now:

...

It looks like I KNOW what I'm talking about..

 

It is a good video, it demonstrates the following to me:

That, with an unknown set of difficulty settings it is possible to:

1. Pull 11.1 G instantaneous G in the DCS spitfire without breaking the airframe

2. It is possible to hold around 6G continuous (varies from 4 to 11 and back down to 2) for 3 seconds without breaking the air-frame (during this point of the video 1:02 to 1:05 it's in external view, so we cannot see if the pilot is greying out at all)

 

It does not, however, demonstrate:

1.Whether such a load is possible in the other types in DCS

2 Whether the pilot has begun to grey out at all under these conditions

3.What G load "instantaneous" or "continuous" is required for a failure to occur

4. Where on the air-frame the G-load is being recorded (Datum point or elsewhere?)

 

Here's how I'd set up a controlled test:

1. similar entry into the maneuver, noting altitude and airspeed at the point of entry

2. play the maneuver at normal speed from in-cockpit to get full view of instruments, and pilot greyout (if any)

3. replay the maneuver at normal speed from external view

4. replay the maenuver at half or quarter speed to show the amount of time under G load

5. conduct the maneuver 2 more times to confirm accuracy

6. conduct a simlar maneuver, but this time designed to break something, noting the G load that was present at that time

7. conduct similar meneuvers to observe effects with other air-frames

8. attempt to reproduce the same G loading with other manuevers in other air-frames to confirm their G-load capability

 

 

Furthermore, one of our guys at SoW did some calculations based on visual observation of a Spitifre failing under G load a while back (http://www.stormofwar.org/phpBB3/viewtopic.php?f=36&t=5934). His calc determined that 11.4 instantaneous was enough to snap the wing off. So your 11.1 in this video is only a tiny fraction below the failure point.

See this video:

 

 

 

And the attendant calculations here:

Okay, first, let's extract the data. For this I stepped through the video frame by frame.

gforces_example.png

Look at the pitch:

This is linearly increasing from t = 10.5 to 11.5. Fit a line to this, and you'll get a slope of approx. 35 deg/s. Convert this to angular velocity (symbol = w, units = radians per second). Because the change was linear, this means it is uniform circular motion.

w = 35 deg/s = 0.611 rad/s

Angular acceleration, a, is (w^2 r), where r is the radius of curvature. But we don't know what r is.

But angular acceleration is also given by v^2 /r.

That means that

a = w^2 r = v^2 / r.

Rearrange to get:

r^2 = v^2 / w^2

r = v / w

Going back to the data, the IAS varies from 575 to 557 km/h. Again it is roughly linear over that range, so we can take the mean. This is v = 565 km/h

But this is IAS. We need TAS.

For this, I'll assume a roughly standard atmosphere and that the altitude is roughly 1130 metres. This is roughly 3700 feet. So the TAS is 599 km/h (REF).

599 km/h

= 166.4 m/s

So, we can now calculate r.

r = v / w = 166.4 / 0.611 = 272 m

With either velocity and r, we can calculate the centripetal force.

a = v^2 / r = 166.4 * 166.4 / 272 = 102 m^2/s

The acceleration due to gravity is 9.8 m^2/s. So, the centripetal acceleration is

102 / 9.8 = 10.4 G

But, you are at the bottom of the curve, so the gravity vector itself is added.

This 1 G, but you need to allow for the pitch and bank. Let's say pitch = 10 deg at the moment of break, and that the bank was about 5 deg.

cos( 5 deg ) * cos (10 deg ) * 1 = .97 G

So, still close to 1.

Thus, the total force would be about 11.4 G.

I'd say my errors are a about 2% per step on 3 steps. That's a total error of +/- 5 %

Now, if we compare that to the registered data, it was max'ing out around 10.9 G. However, that is probably a frame average, and my figures have about 5% error.

In any case, the G-calculations look pretty good.


Edited by philstyle

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My video clearly demonstrates what I said: Spitfire is able to pull +11Gs (I saw even +12Gs) without it and its pilot to suffer the natural and obvious consequences.

 

 

 

Your calculations, on the other hand, are based on erroneous data so stop posting them here.

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My video clearly demonstrates what I said: Spitfire is able to pull +11Gs (I saw even +12Gs) without it and its pilot to suffer the natural and obvious consequences.

 

 

 

Your calculations, on the other hand, are based on erroneous data so stop posting them here.

 

Erroneous data?

 

What proof?

 

Where's your attempt?

 

Your calculations?

 

What g-loading should the Spitfire fail at structurally?

 

WHERE IS YOUR EVIDENCE?

 

Do you even comprehend that there are ramifications to pulling this kind of g in the DCS Spitfire? That it can drastically reduce the ability to survive subsequent excursions into positive g?

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My video clearly demonstrates what I said: Spitfire is able to pull +11Gs (I saw even +12Gs) without it and its pilot to suffer the natural and obvious consequences.

Your calculations, on the other hand, are based on erroneous data so stop posting them here.

 

The calculations I posted confirm very similar to what your video shows. . . claiming (sans rationale) that they are "erroneous" doesn't do your argument any favours.

I leads one to believe that you might not have paid much attention to them at all.

From the linked video, a max value in the maneuver before wing-break of "about 11.4G" was derived from the calcualtions. This is only 0.1G (0.8%) away from the G shown in your video (which on multiple reviews as slow as I can get youtube to playback does show an 11.3 at one point). Now you *might* have achieved 12G at some point, but you asked us to assess your video - not something you saw but didn't show. The video does not show 12G. Adding that in to the mix now, sans data, is specualtive and nothing more.

 

As for this statament "the pilot to suffer the natural and obvious consequences", I doubt you even know what these are. Theres no medical data provided to show an instantaneous 12G (assuming you really did see 12G) on the human body . . so you've not made any substantial kind of claim here that can be reasonably assessed by anyone.

 

John Paul Stapp famously conducted G rocket tests on himself.

He survived 46.2G. instantaneous (despite some broken bones) and at 18G instantaneous reported grey outs. His report of 10G was that it was "quite pleasant".

But Stapp has to be seen as an outlier. Despite that, I think many ametuers will be rather shocked at how high the report G values were in his experiments. I certainly was.

 

Continuous G is less "survivable", and is often confused for instantaneous G. U.S. DoD Studeis from the 1950s 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.

The 5.4 G 1/s rate is a 5 1/2 second test

The 4.5 G 2/s rate is a 9 second test

Extrapolating those figures gives us jsut on zero seconds for 10.9G.

So 11 seconds is basically the average instantaneous G for G-Loc onset that could be expected without G-suit or straining. Now, in amazing's video we're not looking at zero seconds exposure, but 3 seconds and the G climbs and drops back again in that period . . so there are still some vagaries here.

 

But we must remember that the US DopD study is assuming no G suit or straining. Our DCS pilots possible don't have "G" suits**, but there were trained to strain, so they can pull more G continuously than the above "average" times and rates before G-loc.

G-suits started being used by spitfire pilots in 1942, incidentally. No 807 Squadron (Seafires) were the first to have pilots equipped with the Franks Flying Suit Mk I in 1942.

 

So based on that, it's not wildly specuative at all that a pilot might not suffer G-loc in the maeuver you showed, assuming the pilot strains (abdominal tensing, sharp breathing). Unfortunately, we can't see if your pilot was suffering greyout effect, due to your decision to stick only with external views. I'd like to see the same from the cockpit, but I've already stated that only to be met with dismissive shorthand from you in response.

As before, your video is a good start. But it's just a start. And it has quite a few gaps that need to be filled before is gives us anything more than a shapshot data point.

It certainly might still turn out that the opinion that the Spitfire/ Pilot in DCS can sustain un-realistically high G loading. But the video provided certainly doesn't get us very close to that conclusion.

 

Finally to adress your last remaining issu, that "Spitfire is able to pull +11Gs (I saw even +12Gs) without natural and obvious consequences"

We can now see that, in fact, Pulling 11.7G casues total catastrophic failure of the Spitfire wing.

Whats more, just 9G (max) is apparently enough to structurally weaken the spitfire airframe, so that a third subsequent 9G maneuver will result in catastrophic failulre.

 

The Spitfire airframe IS weakend/damaged by just 9G. You just cant see the damage until you try to stress the air-frame again.

 

Quick tests.

Spitfire - two runs - catastrophic failure at 11.7G

This next test was three 9G (appx) pull-outs (only third is shown) - the fourth attempt induced failure at 9G so the air-frame appears to weaken with abuse.

 

 

This is why we do repeated tests, and just don't selectively post one-off data points that appear to prove a point, but do little more than cloud the issue.


Edited by philstyle

On YouTube: https://www.youtube.com/philstylenz

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I'm sure Mr. Grey has plenty of experience in the real deal, and I'll believe whatever he tells me about the real spitfire. But DCS is not a real spitfire, its a video game based off of math that people made up so that it is closeish to what the real thing does. It is not perfect, it will never be perfect. Flying a video game and flying a real plane are very different things and you can put 10 different spitfire pilots in front of DCS and they will all say something different. Especially when they are the one trying to sell that video game to you, and the entire brand is based off of that video game being the most realistic thing out there (this isnt anything nefarious, just how the world works). IMO "Nick Grey said its good, therefore there mustn't be any problems at all and its all perfect" is a silly argument.

 

The spitfire turns quite well, its supposed to, not really surprised at this. Don't think there is really an issue here. Maybe there is a discussion to be had about how well poorly flown aircraft retain energy in DCS, people pulling way too hard, constantly in a stall not really losing a whole lot of energy. This is a general thing though, maybe it stands out more for the spit because of how inherently good the spit is at dogfighting, but it is all aircraft.

 

MAD did some dive tests a while ago that didn't really seem to make much sense compared to what one finds in historical flight tests. These would be interesting to discuss/replicate and see if there is anything there.

 

Other than that the rest of this namecalling (luftwhiner, noob, whatever your personal choice is), getting angry saying your favorite plane is underpowered and the opposition are all noobs and making silly videos doesn't really get us anywhere.

 

Also just for the sake of completeness in regards to Amazings video. No issue here. Most planes make more than enough lift to break themselves at Clmax at high speeds.

 

See below if it helps: In the top graph the line on the right is the structural limit (turn radius for which you reach the G-limit of the aircraft at that speed) and the left is the turn radius at Clmax for that speed considering bank angle required to maintain level flight. Absolute min radius is at 90° bank (all lift used for turning). attachment.php?attachmentid=201636&stc=1&d=1546958545

9./JG27

 

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Pretty much what Defaulface said. Im not sure what amazingme's video is trying to prove. That the Spitfire shouldn't be able to pull 11g's ever?

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The discussion started when birdstrike asked the devs what's the algorithm for 109's stickforces. As it was capable for pulling for than 6 Gs, but not so much in DCS due to the stickforces. I said that the Spitfire is able to pull 12 Gs and someone wanted a proof, so I proved it can with that short game footage.. That's all..

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I'm sure Mr. Grey has plenty of experience in the real deal, and I'll believe whatever he tells me about the real spitfire. But DCS is not a real spitfire, its a video game based off of math that people made up so that it is closeish to what the real thing does. It is not perfect, it will never be perfect. Flying a video game and flying a real plane are very different things and you can put 10 different spitfire pilots in front of DCS and they will all say something different. Especially when they are the one trying to sell that video game to you, and the entire brand is based off of that video game being the most realistic thing out there (this isnt anything nefarious, just how the world works). IMO "Nick Grey said its good, therefore there mustn't be any problems at all and its all perfect" is a silly argument.

 

It wasn't a argument point, what it was that not only does ED do the most advanced FMs out there, they are also signed off on real pilots whenever possible, the fact that Nick Grey has had many hours in many Spitfires, and has had a hand in tuning the FM is an important consideration to take when discussing perceived faults with the Spitfire. Also, Nick will be the first one to tell you that flying in DCS isnt like the real thing, because there are many aspects of real flight and being in motion you will never get from a computer simulation. So saying I said it was perfect at any point is silly in its self, the POINT is we do everything we can to verify and check the realism of aircraft in DCS World. Its why Yo-Yo is off hanging out with a Luftwaffe pilot right now.

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