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Dive speed limitations - a question of philosophy


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Why are some aircraft held to their limitations from the aircraft manual, while others have much higher limits in excess of what was in their historical manuals?  It seems like a two different philosophies have been applied for different aircraft in this regard.  

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23 minutes ago, KW_1979 said:

Why are some aircraft held to their limitations from the aircraft manual, while others have much higher limits in excess of what was in their historical manuals?  It seems like a two different philosophies have been applied for different aircraft in this regard.  

Since this is philosophy, to answer your question, we must have an Allegory with a capital A.

Imagine everyone is chained up in cave, in front of a wall upon which are thrown shadows of various aircraft. For your whole life, you see only the shadows. Then one day you find that your chains have come undone, and you are able to turn around. What you see is the source of the shadows - a fire, with little toy airplanes being moved in front of the flames to cast shadows on the walls. Beyond the fire you can see a bright light, and you head towards this light. Eventually you emerge from the cave into the real world - blinding and brilliant, and you can even see real planes flying around, and now the shadows simply seem to be pale imitations of reality, fundamentally unsatisfying.

You head back into the cave and try and convince your compatriots chained to the wall that what they are seeing is a mere shadow, and the real world lies beyond this cave. But they do not listen, for all they have ever known and seen is the shadowy planes on the wall - for them it is reality, while you have seen the true (some may say, 'ideal' forms) of the world and planes.

By all this, we can arrive thusly at the obvious conclusion: I think we all need to get out more.

/Plato was a chump and the allegory of the cave sucks

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Based off the numbers listed here.

 

From the testing I’ve done in game, most aircraft can exceed those numbers by a bit of a margin before parts start falling off.

 

The Spit V, Spit IX, Tempest, P-38, P-39, P-47 and P-51 all have the exact limits from their flight manuals.

 

By comparison, the P-40, Bf109s, Fw190, and BF110G2 all have higher limits ( sometimes by 100 kph) then what appear in manuals (the MC202 also has a highly suspect 850 kph dive limit).

 

I can’t speak to the Russian aircraft as I can’t read any of those manuals, but based on some very old posts on the topic it appears that many of the “older” (as in, came with BoS and BoM) aircraft have these increased limits, while most of the “newer” airplanes seem to have been given the limits straight out of the manual.

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In game spec limits are from manuals safe speed, when you go abow it your in danger zone that is for axis +~50-100kmh of manual , russian ~0-50kmh if your lucky and american and british also ~100kmh+ from what i could see.

 

for example on yaks you get around ~750 at and Yak-9 ~800 at best, on 109s 190s 51s you get ~900kmh, on p-38 or Spit9s around ~830, p-47 ~940  Tempest ~950, 262 ~1150 when you lose alerons and so on... but most complains i could see are that russian still get to mutch lagg3 especialy , first time i see complain about 202.

 

same logic as to engine time limit that is by manual but you get some exra time after manual time run out, so here your in that red danger zone with dive speed also when you go abow manual /spec limit.

Edited by CountZero
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We cannot give the manual to the plane because the plane has gainset the manual.

 

@LukeFFThat was a joke regarding the first post and others...https://www.goodreads.com/quotes/819202-justice-might-it-is-right-that-what-is-just-should-be

 

Justice is subject to dispute; might is easily recognised and is not disputed. So we cannot give might to justice, because might has gainsaid justice, and has declared that it is she herself who is just. And thus being unable to make what is just strong, we have made what is strong just.”

Edited by [TLC]MasterPooner
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On 9/15/2020 at 8:32 PM, KW_1979 said:

Why are some aircraft held to their limitations from the aircraft manual, while others have much higher limits in excess of what was in their historical manuals?  It seems like a two different philosophies have been applied for different aircraft in this regard.  

 

All aircraft are modelled after tests and historical references of dive speeds (safely) obtained, not after the manual figures. In some cases, historically, manual figures may conincide with actual maximum (safe) performance, in most cases, actualy limits are higher than the manual limits.

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My dude blacks out at 3G. i've done 3G, it was barely noticeable.  So much abstract and academic testing is just silly. Put a dude in a 3G capable airframe and show him what it is like.. Chances are he'll be laughing his ass off, not passing out.

I mean serously, to me this is the one big failure of this seriies. It's too tied down by boffin space magic and slide rule numbers. The real world is a lot more dynamic. Just go for what feels right and buld on that.

Edited by Ace_Pilto
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Just my five cents on this subject, this is seen all the time in engineering industries. Specifications, safety margins and tolerances of rated equipment can differ to what is written on paper, this depends a lot on how robust the company's processes and I suppose internal philosophy is. If you are working for a reliable and sound company, they will give a decent margin of error / tolerance to guarantee the desired performance so that the numbers are reliable and repeatable for most conditions.

 

Manufacturers do not all share the same philosophy however...

 

That's why, often - testing of equipment is made by a user/operator etc to confirm it meets requirements. Why? because under certain conditions those numbers may be difficult to achieve and these may vary depending on how repeatable the original tests were by said manufacturer.

 

Some officially published documents and manuals will go ahead and give the Vne (never exceed speed) and some give recommended safe limits... which (provided the equipment meets/exceeds standards) some manufacturers will TYPICALLY exceed if they have good controls and processes - but not always... (think quality control variation, process adherence etc).

 

Example, one month very high quality parts are delivered at high end of tolerances, the next month a factory is hit by bombs and you're at the bottom end of your acceptable limit - yet your quoted max speed is the same... depends on how critical the part is... but you see the problem.

 

These limits are nowadays more standardised due to international / industry regulations with strong consequences attached but back in the 30's... eeh... it was a pioneering age and regulations/standards were more lax.

 

Different manufacturers would have got different results from the same aircraft based on their company's tolerance(s) / margin of error and measurement methods... while others simply wanted to display the aircraft's best performance number on paper for marketing and other reasons.

 

If the company was trying to sell a large order of aircraft to a government and its success could make or break that company .. they may put the absolute limit down with little or no safety margin to appear more competitive.

Edited by Aurora_Stealth
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1 minute ago, [DBS]Browning said:

The 'do not exceed' depth for German U-Boats was far shallower than their actual capability. I wonder if such conservative limits where the norm in German aircraft also.

One has to wonder how often the U-boats didn't come back because a particular one didn't have the same excess capability over the specs as another one did. Who would know if it was killed by an ASW aircraft, or simply dove too far and then...pop.

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Well this swung wildly into the realm of jokes and trolling.  Lets see if we can swing back towards a technical discussion.

 

On 9/17/2020 at 6:58 AM, JtD said:

 

All aircraft are modelled after tests and historical references of dive speeds (safely) obtained, not after the manual figures. In some cases, historically, manual figures may conincide with actual maximum (safe) performance, in most cases, actualy limits are higher than the manual limits.

 

After the research I did related to the issue with the P-51's landing gear doors and high speed elevator function, I'm more than a little skeptical that the dive speed limits are based on testing, rather than on the manual limits.  For one, I have a hard time believing that detailed dive testing data still exists for most of the aircraft in question (if it was even done).  And secondly, what does exist that I've looked at doesn't support some of the limits we see in game.

 

One of the big examples in game is the Bf109 series - there's actually some test data available, and the dive limits of all of them in game are far in excess of what was published by the RLM and Messerschmitt, or what was achieved in testing.  The early aircraft were all limited to 750kph per their manuals as best as I can tell. 

BF109E manual - pg 7 (11th page of the pdf)

Bf109G-4 manual - pg 10 (9th page of the pdf)

 

With the move to the F model there appear to have been a number of issues with aircraft lost in dives.  Certainly some of this was due to weakness of the tail - external stiffeners had to be added, but there appear to have been issues with loss of wings as well.

 

Additional dive speed restrictions

 

 

Radinger & Otto's "Bf109 F-K" goes into some depth on the topic:

 

Book Cover

Page 16

Page 17

Page 18

 

Here's the actual original test report from the tests above posted on Mike Williams page.

 

The highest indicated airspeed they recorded (using an F-2 with modified larger tail, and ailerons limited to 50% travel) was a mere 737 kph.  One interesting point here is that he mentions running into aileron over-balance at around 850-890 kph (obviously true airspeed) - in the curves seen in the test above that occurs at around 7.5km, which would indicate a critical mach number for an unmodified 109 somewhere in the neighborhood of .77 mach (I'll circle back to this later).  On a side note, this is incredibly similar with what I saw from testing on the Allied side - test pilots in controlled conditions didn't even reach the low altitude manual limits - it's not clear if this is due to the risk being too high, or simply the fact that everyone was more interested in the compressibility factors encountered at higher altitude.

 

Later 109 manuals had the expanded dive speed limit guidance.

Bf 109G-6 manual - pg 11 (page 9 of the pdf)

 

The later G series and the K had an enlarged tail, although it's not entirely clear if this is the same profile as the test unit used on that F-2, and its also not clear if it was added to cope with higher engine powers, or for dive issues, or just as part of switching to wooden construction to save resources.  Interestingly, even after the testing, more conservative limitations, and the enlarged tail, other issues popped up.  The wooden construction of the new tail was apparently vulnerable to damage from exposure to moisture.

 

Again from Radinger & Otto:

 

Page 25

Page 26

Page 27

 

The part about the inspections of Jg27 and Jg26 aircraft in December is interesting, as this would be a mix of G-14, G-14/AS, G-10 and K-4 aircraft, with roughly 1/4 of them having problems.

 

I haven't been able to find a full copy of the 109K manual, lots of sections on armament and rigging, but not the Teil 0 that would contain any dive speed limits if they were published.  After digging around the web I did see some posts in a few places referring to some test which proved that 850 kph was valid dive speed limit for the K-4, but I've had no luck finding it.  AFAIK the only real significant airframe changes of the K were the tall wooden tail (like on the G-14 etc) and a change to the aileron trim tabs so it does seem strange that it would have such a significant advantage there.

 

In game, the 109s (except the K which is MUCH faster ~ 950 kph) can all dive to right about 890 kph indicated, where they start shedding parts.  This strikes me as wildly optimistic given everything above.  Playing around with the K4, I was able to record mach .86 @ 21,000ft, mach .87 @ 15,000ft, and mach .85 @ 10,000ft and then recover.  I think the manual limits for these aircraft were put there for a reason, and being able to exceed them by 150+kph is pretty unrealistic - particularly when only some aircraft are given this buffer while others are held more closely to their manual limits.

 

Hopefully some others can pitch in with other manuals or test data that I'm not aware of.

 

 

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11 hours ago, KW_1979 said:

After the research I did related to the issue with the P-51's landing gear doors and high speed elevator function, I'm more than a little skeptical that the dive speed limits are based on testing, rather than on the manual limits.  For one, I have a hard time believing that detailed dive testing data still exists for most of the aircraft in question (if it was even done).  And secondly, what does exist that I've looked at doesn't support some of the limits we see in game.

 

All manual figures given for German aircraft are either calculated with a safety factor of 30% (I think that's dynamic pressure, but could be IAS directly) or flight tested to the point where flutter starts. Flutter is Mach-related, not IAS. So if you have a test where flutter starts at 0.77, that's one limit, but not related to IAS, and the other is manual speed down low, times square root 1.3 = 1.14 (or 1.3). So 850 is safe by design (could even be 975).

 

Static load issues of Bf109 in dives were mostly related to pilots trimming nose up during the dive to counter a nose down pitch, only to shed wings when pulling out.

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On 9/18/2020 at 2:06 AM, Ace_Pilto said:

My dude blacks out at 3G. i've done 3G, it was barely noticeable.  So much abstract and academic testing is just silly. Put a dude in a 3G capable airframe and show him what it is like.. Chances are he'll be laughing his ass off, not passing out.

I mean serously, to me this is the one big failure of this seriies. It's too tied down by boffin space magic and slide rule numbers. The real world is a lot more dynamic. Just go for what feels right and buld on that.

 

You have to model something, you ask 10 ppl in the sim community and get 12 different answers all fixed in their opinion they are correct... 

😋

For the most part It seems pretty plausible to me, even if I don't agree with some "feelings" that its not quite right, I'm prob wrong and it's correct, and the things I think they got right are probably not...

I do feel the G force needs tweaking though... +ve /-ve rapid movements seem out as well as quick onset blackouts are off..

 

But that's off topic to OP's question

Edited by =RS=Stix_09
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I mean, during the compressibility tests in later 43 and early 44, two flights were performed with a Spitfire MkIX. One reached M 0.89, the other one M 0.92. The first one took no damage, the 2nd one had the propeller disconnect but the pilot glided it back to base. In neither of the tests the control surfaces have disconnected, yet in this game ailerons will fall off waaaay before you even get close to mach 0.8, let alone 0.89. Not sure what that was modeled after.

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2 hours ago, ACG_Onebad said:

I mean, during the compressibility tests in later 43 and early 44, two flights were performed with a Spitfire MkIX. One reached M 0.89, the other one M 0.92. The first one took no damage, the 2nd one had the propeller disconnect but the pilot glided it back to base. In neither of the tests the control surfaces have disconnected, yet in this game ailerons will fall off waaaay before you even get close to mach 0.8, let alone 0.89. Not sure what that was modeled after.

 

Yeah, it really strikes me that the way dive limits are handled for the various planes is just all over the place, rather than there being a consistent philosophy.  You could make arguments for either direction - give everything a buffer, or stick to documented limits.  But it should be consistent.

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On 9/23/2020 at 9:11 AM, KW_1979 said:

 

I haven't been able to find a full copy of the 109K manual, lots of sections on armament and rigging, but not the Teil 0 that would contain any dive speed limits if they were published.  After digging around the web I did see some posts in a few places referring to some test which proved that 850 kph was valid dive speed limit for the K-4, but I've had no luck finding it.  

 

 

 

This?109k4-divelimits_IASspeedgauge.jpg.44791419d3f49d8e030a5051f0dfb25a.jpg

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On 9/24/2020 at 2:09 AM, KW_1979 said:

Yeah, it really strikes me that the way dive limits are handled for the various planes is just all over the place, rather than there being a consistent philosophy.  You could make arguments for either direction - give everything a buffer, or stick to documented limits.  But it should be consistent.

 

Consistency ... is the right word? i think yes.  I miss some consistency in more aspects of game. One is subject of this post, others are about damage of weapons, visual representation of damages and how it affect to aerodinamical caracteristics and DM for some planes are out of the "line".

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On 9/26/2020 at 9:08 PM, KW_1979 said:

I wonder what Rustsatze it’s referring to in the right column?  External stores presumably.  Which manual is that from?  Thanks for posting it.

 

Rüstsaetze is for external stores such as bombs and gondolas. 

 

The manual is L. Dv. T. 2109/Fl Bf 109K-4 Bedienungsvorschrift-FL, Teil 2: Wartung, (Operating Instructions, Part : Servicing, Stand Oktober 1944, Ausgabe Januar 1945, page 11.

 

Two dive limitations table is given, one for the speed compensating speedometer (shows roughly ~TAS, as in Me 262), and one for the usualIAS speedometer; the limitations show the IAS limits.

 

An interesting thing about DB 605D in the K-4 is that the engine, unlike previous 60x series it had a supercharger bleed valve so throttling back 'to the white' mark was no longer neccesary in dives for the K-4/G-10.

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57 minutes ago, MiloMorai said:

Please note the altitudes for the dive limits.


It is interesting that the higher altitudes are really unchanged (except to extend the table up to reflect the higher ceiling provided by the DB605D), and it’s only below 3km in the realm of dynamic pressure limits (as opposed to Mach related limits).  My rather uneducated guess is that the additional gear fairings helped alleviate the risk of the gear getting sucked out of the wheel well - the memo I posted above which appears to introduce the more comprehensive dive speed limits mentions unintended gear deployments as one of the problems they were seeing in high speed dives.

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Early G models had speed indicators that only went to 750, and in German aircraft you don't get limits that are higher than the range of the instrument. Sounds ridiculous, but it's true - if the pilot doesn't know how fast he's going, he's not permitted to go there, case closed. So for early models this alone would be a limiting factor.

 

Not sure when the indicator was changed (anyone?), but the K definitely had an indicator with a range up to 1000.

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It seems that dive speed limitations are tricky to assess due to their complexity. This video shows an interesting attempt at comparing the limits of some top WW2 fighters. Even in the rather detailed analysis of the available data, there are many uncertainties and hand-wavy assumptions.

 

Aileron reversal, control lockup, control ineffectiveness, nose-down tendency, and outright structural failure are mentioned as possible risks. I'm not sure how all these effects could be modeled consistently in a game where the limit is usually simplified to shedding of control surfaces.

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10 hours ago, Mitthrawnuruodo said:

It seems that dive speed limitations are tricky to assess due to their complexity. This video shows an interesting attempt at comparing the limits of some top WW2 fighters. Even in the rather detailed analysis of the available data, there are many uncertainties and hand-wavy assumptions.

 

Aileron reversal, control lockup, control ineffectiveness, nose-down tendency, and outright structural failure are mentioned as possible risks. I'm not sure how all these effects could be modeled consistently in a game where the limit is usually simplified to shedding of control surfaces.

I think this is the correct answer. The limiting effect varies widely across aircraft: Mach tuck, flutter, shifts in stability, and porpoising, are some of the more dangerous that come to mind. 
 

I know the devs are aware of the simplicity of the compression modeling and have mentioned that they hope to improve it in the future. With that I would hope would come more tailored and aircraft specific behaviors at these high speeds as right now there is much to be desired in my opinion. Especially aircraft like the spitfire which has an extremely high critical Mach number sheds control surfaces far before it reaches those critical values.  Similarly, the pony should have enough control authority down in the mush to easily induce structural failure at high speed but right now it starts to lock up around 400 mph. 

 

 

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On 9/16/2020 at 1:03 AM, CountZero said:

 

for example on yaks you get around ~750 at and Yak-9 ~800 at best, on 109s 190s 51s you get ~900kmh, on p-38 or Spit9s around ~830, p-47 ~940  Tempest ~950, 262 ~1150 when you lose alerons and so on... but most complains i could see are that russian still get to mutch lagg3 especialy , first time i see complain about 202.

 

I would complain about russain planes. Maybe not with the Dive limit when they brake but te dive behaviour of the plane. The 109 manual for example established the limit on 750 kph and awares not to use too much trim because the THS has quite big effect and that is dangerous if you put too much loads on the plane mooving this THS. Also says to trim the plane befor the dive so you need to push the stick foward to mantain it. There are some testimonies of pilots passing this limit with quite a huge margin and also others that mention structure fatigue after 2 recoveries over the limit due to the huge loads on the recovery. That is happening over 750km/h and on the game the behave is close because at 800 you really need to use the trim to recover and the plane is like a brick 

 

On the other hand we have a Yak on the game that you can barely notice that you are on the limit. It happens to me a lot of times, nose down feeling the plane Ok and suddenly losing an aileron because to my surprise I was already on the limit. That is a HUGE diference with what manual descrives where you have handling problems and things to consider doing  to recover dives at 600Kph speed where the 109 should be just stiff on controls compared to his combat speeds and that is all. 

 

 

 

 

I quote this part of the Yak manual translated in to english

The entry on the dive must be made starting with a turn or with a half  roll to avoid the fall of the pressure of the oil.   It is allowed to do the  dive at any angle, reaching during the exit of the same speed of 650 km / h by the indicator, both with the gas and without it.   During the  dive do not allow the over-revolution of the propeller above 2,800 r.p.m.   During prolonged diving do not allow the water to cool: - for the airplane equipped with the M-105P engine - below 40ºC; - for the plane equipped with the M-105PF engine - below 60ºC.   The exit of the dive must be done by gently stretching the lever of the plane and at a speed not less than 340-350 km / h.   Do not make sudden movements with the altitude rudder during the departure of the dive, otherwise the aircraft, regardless of the speed, will begin to wobble from one wing to the other and the process of the exit of the dive will be longer."

5b02cb7ca2807_BUCEOYAKruso.thumb.png.88ee82638bcbdeed84e896380ac2286e.png

 

From Yak3 manual

Before diving, put the plane on a horizontal flight. at about 350 km / h. To dive push the lever if the speed is less than 300 km / h. Otherwise, since it takes a great effort to put a plane in the dive.   It can be dived without touching the compensator up to 300 km / h. It is not recommended to do it until 400 km / h. At this time the lever operation will require a lot of effort and it is necessary to adjust the elevator to reduce it. If it is not reduced, the plane leaves the dive with too much effort.   To dive enter from a turn to avoid unnecessary overloads or drops in oil pressure. diving is authorized with or without gases, provided that the final speed reached does not exceed 650 IAS.   In a dive of 45-60 ° the final speed must not exceed 620-630 km / h. In a dive 70-80 ° must not exceed 600 IAS.   At the end of a dive, the sudden movements of the lever must be avoided, since they generate over loads that can end up with the breaking of a wing or an auger.

 

 

 

 

 

You can see that with all those problems at 620-650 Kph that ARE NOT on the game and the limt of the speed you can stay on steep angles is quite restrictive I guess because over those speeds the plane would be almost imposible to recover, would suffer damage or so. The handling over those limits would be so much worse and probably a high angle of diving would be just imposible to recover just because of handling and not just because the structure not suporting the loads.

 

So is not just about speed limit complains. While the 109 is one of the planes that is more like a brick at those high speeds the yak with noticeable handling problems not just for control loads because of handling, is much easyer and nimble to fly on the limits and that is why the complains

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On 9/17/2020 at 4:18 PM, [DBS]Browning said:

The 'do not exceed' depth for German U-Boats was far shallower than their actual capability. I wonder if such conservative limits where the norm in German aircraft also.

Do not exceed depths for submarines take into account criteria that are not applicable to aircraft. There are of course safety limits as there would be on aircraft but submarine dive depths have extra stuff above that.

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2 minutes ago, Barnacles said:

Do not exceed depths for submarines take into account criteria that are not applicable to aircraft. 

 

Well...yes but...not really.  All these limits are theoretical and established by engineers and designers.  No one was asked to dive a plane to their death to establish at what speed it broke up just as no one was asked to dive a u-boat to establish at what depth it broke up.

 

  

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13 minutes ago, DD_Arthur said:

 

Well...yes but...not really.  All these limits are theoretical and established by engineers and designers.  No one was asked to dive a plane to their death to establish at what speed it broke up just as no one was asked to dive a u-boat to establish at what depth it broke up.

 

  

What I meant was, it's incorrect to say for example there's a 50% safety margin on U-boat max dive depth so that's the safety margin that German engineers in general used.

Because that 50% includes a load of different stuff, not just the engineering tolerances. And ok it's theoretical, but it's fairly concrete numbers they use.

 

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On 9/17/2020 at 5:21 PM, RedKestrel said:

One has to wonder how often the U-boats didn't come back because a particular one didn't have the same excess capability over the specs as another one did. Who would know if it was killed by an ASW aircraft, or simply dove too far and then...pop.

 

Now i wonder ... how deepcan you dive with a U-boat in IL2?

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4 hours ago, E69_geramos109 said:

I would complain about russain planes. Maybe not with the Dive limit when they brake but te dive behaviour of the plane. The 109 manual for example established the limit on 750 kph and awares not to use too much trim because the THS has quite big effect and that is dangerous if you put too much loads on the plane mooving this THS. Also says to trim the plane befor the dive so you need to push the stick foward to mantain it. There are some testimonies of pilots passing this limit with quite a huge margin and also others that mention structure fatigue after 2 recoveries over the limit due to the huge loads on the recovery. That is happening over 750km/h and on the game the behave is close because at 800 you really need to use the trim to recover and the plane is like a brick 

 

On the other hand we have a Yak on the game that you can barely notice that you are on the limit. It happens to me a lot of times, nose down feeling the plane Ok and suddenly losing an aileron because to my surprise I was already on the limit. That is a HUGE diference with what manual descrives where you have handling problems and things to consider doing  to recover dives at 600Kph speed where the 109 should be just stiff on controls compared to his combat speeds and that is all. 

 

 

 

 

I quote this part of the Yak manual translated in to english

The entry on the dive must be made starting with a turn or with a half  roll to avoid the fall of the pressure of the oil.   It is allowed to do the  dive at any angle, reaching during the exit of the same speed of 650 km / h by the indicator, both with the gas and without it.   During the  dive do not allow the over-revolution of the propeller above 2,800 r.p.m.   During prolonged diving do not allow the water to cool: - for the airplane equipped with the M-105P engine - below 40ºC; - for the plane equipped with the M-105PF engine - below 60ºC.   The exit of the dive must be done by gently stretching the lever of the plane and at a speed not less than 340-350 km / h.   Do not make sudden movements with the altitude rudder during the departure of the dive, otherwise the aircraft, regardless of the speed, will begin to wobble from one wing to the other and the process of the exit of the dive will be longer."

5b02cb7ca2807_BUCEOYAKruso.thumb.png.88ee82638bcbdeed84e896380ac2286e.png

 

From Yak3 manual

Before diving, put the plane on a horizontal flight. at about 350 km / h. To dive push the lever if the speed is less than 300 km / h. Otherwise, since it takes a great effort to put a plane in the dive.   It can be dived without touching the compensator up to 300 km / h. It is not recommended to do it until 400 km / h. At this time the lever operation will require a lot of effort and it is necessary to adjust the elevator to reduce it. If it is not reduced, the plane leaves the dive with too much effort.   To dive enter from a turn to avoid unnecessary overloads or drops in oil pressure. diving is authorized with or without gases, provided that the final speed reached does not exceed 650 IAS.   In a dive of 45-60 ° the final speed must not exceed 620-630 km / h. In a dive 70-80 ° must not exceed 600 IAS.   At the end of a dive, the sudden movements of the lever must be avoided, since they generate over loads that can end up with the breaking of a wing or an auger.

 

 

 

 

 

You can see that with all those problems at 620-650 Kph that ARE NOT on the game and the limt of the speed you can stay on steep angles is quite restrictive I guess because over those speeds the plane would be almost imposible to recover, would suffer damage or so. The handling over those limits would be so much worse and probably a high angle of diving would be just imposible to recover just because of handling and not just because the structure not suporting the loads.

 

So is not just about speed limit complains. While the 109 is one of the planes that is more like a brick at those high speeds the yak with noticeable handling problems not just for control loads because of handling, is much easyer and nimble to fly on the limits and that is why the complains

I think it is subjected to some interpretation.

In the case of the of the yak (yak1 with the M105P I suppose) the sudden movement of the altitude rudder (rudder?) what does mean? Kicking full rudder (as much as you can) full to one side? Sudden movement can mean many things but, in any case, I do not think it indicates that with a normal use of the rudder youmust have any problem. I don´t even know if the current FM engine is prepared to deliver that kind of particular flight behaviour. I wish it could but even if it could, and as described, I am not so sure it would be a major problem.

The case of the yak 3 is similar. 600 IAS could be very well near 700kph TAS depending of the altitude. Seems reasonable for high angle of diving (70-80º is near vertical ). I bet most fighters are going to have trouble getting out the dive at those angles depending on the altitude.

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4 hours ago, HR_Zunzun said:

I think it is subjected to some interpretation.

In the case of the of the yak (yak1 with the M105P I suppose) the sudden movement of the altitude rudder (rudder?) what does mean? Kicking full rudder (as much as you can) full to one side? Sudden movement can mean many things but, in any case, I do not think it indicates that with a normal use of the rudder youmust have any problem. I don´t even know if the current FM engine is prepared to deliver that kind of particular flight behaviour. I wish it could but even if it could, and as described, I am not so sure it would be a major problem.

The case of the yak 3 is similar. 600 IAS could be very well near 700kph TAS depending of the altitude. Seems reasonable for high angle of diving (70-80º is near vertical ). I bet most fighters are going to have trouble getting out the dive at those angles depending on the altitude.

Is refering to the elevator not the rudder. Translation is incorrect. The plane is not making that on the game at 600 ias. The Bf109 was rated with 5/5 on a scale germans have for rating the planes restrictions for acrobacies ( I will bring the source ) that means there were NO restrictions performing anything as soon the plane speed does not surpase the limit of the manual there were not such limitation with angle of diving etc. 

To have those problems at this slow speed compare with other planes makes a big difference because a defensive manouver can be just stay on a soft dive and perform a break manouver at 650. A yak would be not able to follow because isues on the handling

Edited by E69_geramos109
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Ah ok. It sounded weird with altitude rudder.

In any case, it doesn´t prove wrong what I said. Sudden movement can be yanking the stick. Not recommended in any plane when coming out of a dive (to avoid overstressing the airframe). If that was the meaning is quite different from a gradual pull that is what you do when coming out of a dive. Any case the exact meaning is, the effect according to the translation you quoted is the wobble that delays the recover from the dive. Far from a cathastrophic effect unless you are running out of altitude and that delay was crititcal.

Again, I wish the FM could model those peculiarities and, if it does, would like the devs consider implement it (not a trivial task if there isn´t more specific information).

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27 minutes ago, HR_Zunzun said:

Ah ok. It sounded weird with altitude rudder.

In any case, it doesn´t prove wrong what I said. Sudden movement can be yanking the stick. Not recommended in any plane when coming out of a dive (to avoid overstressing the airframe). If that was the meaning is quite different from a gradual pull that is what you do when coming out of a dive. Any case the exact meaning is, the effect according to the translation you quoted is the wobble that delays the recover from the dive. Far from a cathastrophic effect unless you are running out of altitude and that delay was crititcal.

Again, I wish the FM could model those peculiarities and, if it does, would like the devs consider implement it (not a trivial task if there isn´t more specific information).

The thing is that the woble makes the recover more slow, is not just a wobbling effect. Samehow affects the effect of the elevator. Not sure how it works and would require research about this effect.

About the yanking you mentioned. My interpretation is that the problem is with a hard pull trying to recover too fast because I do not see the sense of that quore refering to yank the stick up and down if it is talking about the recovery not about performing combat manouvers. I can not see the sense of talking about that kind of yank on this topic becuase  is comon sense that yanking up and down is not what you should do on any plane to exit from a dive.

 

The source I was talking about 

 

 

1891254212_acrobatico2109.thumb.jpg.6c1a33e57dd886453017539eb92891d7.jpg640758667_acrobatico109.thumb.jpg.3e902a66e9f71cac87f00da80c1c848c.jpg

 

 

¿What means the ladeplan of the Bf-109G 2?
-- Groups of use and stress.--
Rules DLA. (Comité Alemán de Aeronaves) 
The next groups of use and stress:
H = Test plane and high performance plane avión de prueba y de alto rendimiento.
G = Comercial mercanciesTransport plane 
P = Comercial pasenger plane
R = Sport plane
S = Training plane
K = Acrobatic planes
Grupo 1 = stress very low
Grupo 2 = stress  low
Grupo 3 = stress normal.
Grupo 4 = stress High (descrived as acrobatic).
Grupo 5 = stress very high (unlimited acrobatic flight).
--------------
So under normal configuración without external loads the 109 is qualified on the H5 "unlimited acrobacies"

 

Edited by E69_geramos109
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2 hours ago, E69_geramos109 said:

The thing is that the woble makes the recover more slow, is not just a wobbling effect. Samehow affects the effect of the elevator. Not sure how it works and would require research about this effect.

About the yanking you mentioned. My interpretation is that the problem is with a hard pull trying to recover too fast because I do not see the sense of that quore refering to yank the stick up and down if it is talking about the recovery not about performing combat manouvers. I can not see the sense of talking about that kind of yank on this topic becuase  is comon sense that yanking up and down is not what you should do on any plane to exit from a dive.

And this is what I said if you read my post carefully. Delayed recovery from the dive. Slower. Taking more time. Also, yanking is not necesseraly up and down but suddenly, with a jerk.

So, in esence, what I understand the manual says is that if you make a sudden pull (like with a jerk) then you will have this wobble effect that will cause a lengthened recovery from the dive. You can pull hard but not sudden is what I understand too. How sudden? I do not know.

Edited by HR_Zunzun
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