La-5 vs FW 190A-3 roll rate comparison

[Crump]

[Edited]

 

In particular, he underlined part of RAE 1231 from this section:

 

"...the time to 45 degrees bank is then fairly accurately estimated by assuming the aircraft commences to roll (at the steady rate) 1/4 second after the pilot starts to move the stick." RAE 1231 p.3

 

He proposed that this invalidated JtD's method of estimation. You can see from my worked example that the result is the same as JtD's method.

 

If you want to think of it in geometric terms, the RAE formula is splitting a rectangle in half from top to bottom in the middle, JtD's formula is splitting the same rectangle in half from corner to corner. The area of the two is the same.

 

Please note the words "fairly accurately estimated". The degrees of bank achieved in an elapsed time equals the area under the curve (look at Crump's post 70 if it is still there for such a curve). RAE 1231 and JtD are using straight line approximations to estimate the area under the curve in the period before steady state roll is achieved. Obviously the RAE report writers thought that this was a small enough error to be ignored, given the other possible noise in the numbers.

 

If anyone wishes to prove them wrong by more accurately calculating the area under the curve, please share. 

 

 

If the base assumption is wrong then the it is just wrong.  The rest is your personal grievances with me ever since we had the discussion on the theory of engines using pressure altitude to operate as well as your not understanding the importance of fuel to air ratio to power.  It is not my fault you did not pick up on these concepts and have waged war on me since.....

 

That being said, after taking a closer look, JtD simply worked the problem from the other end form what I did.  The results are the same.

 

In fact I sent JtD a PM which I will share:

 

 

I looked at what you did again. It is actually the exact same thing I did just from the other direction.

The result is the same. I worked from ADM 295 standard forward while you worked from the Figure 6 number backwards.

 

And for the initial acceleration, you are right except under the conditions given...Fixed aileron deflection and a fixed force then our acceleration will make a difference and the rate will be higher.

 

I do not think that is what they did however.

 

It is pretty easy to see that:

 

ADM 295 times + instantaneous rate + pilot reaction times = Figure 6

 

Or

 

Figure 6 - instantaneous rate - pilot reactions times = ADM 295 estimate.

 

We can discuss this like adults or continue the bullshit you have shown in the past that has made me completely dismissive of anything you say. After all the completely wrong declarations about EAS, compressibility, turning performance, zoom climb, and just about anything else....

 

It is up to you. Consider this an olive branch. Break it or accept it.

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Edited February 3, 2016 by Bearcat

[LLv24_Vilppi]

That being said, after taking a closer look, JtD simply worked the problem from the other end form what I did.  The results are the same.

No, they are not. You got a "range" of values, minimum being 72.5 and maximum 79, with completely ignoring units.

 

You may now have the last word as I will try hard to keep this as the last reply to you about this matter.

[Crump]

 

 

You got a "range" of values, minimum being 72.5 and maximum 79, with completely ignoring units.

 

No PItbullviscous....

 

I got a range of values because I used a little higher math to arrive at the conclusions and understand all engineering values have some error.

 

Nothing else 

Your not following that math has nothing to do with it being correct.

[JtD]

That being said, after taking a closer look, JtD simply worked the problem from the other end form what I did.  The results are the same.

Basically I've already said and read everything I wanted to say and read on the subject. From my side it's closed and there's no need for a continued discussion or debate over one point or the other.

 

On the other hand, roll rate data for the La-5 would be nice, or hard new roll acceleration data for either of the two aircraft in the topics title.

[LLv24_Vilppi]

The British report says that it takes half a second to reach the desired aileron deflection/force of 50lb and the same time for the aircraft to reach steady rate of roll after the stick is first moved. This indeed implies the steady rate of roll is reached as soon as the ailerons are in the desired position, both happening after half a second.

The 75deg/s are the steady rate of roll of the Fw190 at 50lb stick force at 10.000ft at 400mph IAS. At these parameters, it is the maximum rate of roll.

JtD, what's your intuition / educated guess / knowledge on this? Is the acceleration to the steady rate indeed that instatenous in reality (and if not, why wouldn't the report take it into account)? I.e. how big role does inertia, for example, play in all this?

 

I honestly have no intuition at all behind this as I've never calculated anything similar, but the acceleration seems mighty fast to me.

 

Assuming that Ze_Hairy's results are correct, just taking in to account the constant acceleration from the 0.5 sec time to given aileron deflection gives following results:

100 deg/s -> ~107 deg/s

110 deg/s -> ~119 deg/s

120 deg/s -> ~131 deg/s

130 deg/s -> ~143 deg/s

 

Calculated as:

360 deg / ((360 deg / p) - 0.25 s)

 

Where p is the average roll rate over 360 degrees reported by Ze_Hairy.

 

I.e. Ze_Hairy's plot would be somewhat closer to the RAE given values, but still quite far off taking into account the acceleration as it is stated in the RAE report.

 

Of course there are several factors in play, such as accuracy of the test (no disrespect meant at all towards Ze_Hairy here, that's just how experiments are), how BoS models the stick forces and delay to equivalent aileron deflection (i.e. is it even comparable with the RAE settings), are my calculations correct, etc.

Edited January 29, 2016 by PitbullVicious

[Crump]

 

 

JtD, what's your intuition / educated guess / knowledge on this? Is the acceleration to the steady rate indeed that instatenous in reality (and if not, why wouldn't the report take it into account)? I.e. how big role does inertia, for example, play in all this?

 

It is a "ok" very generic ballpark and nothing else.

 

The shortcoming of PB/2V theory is initial roll rate is not taken into account.  The shortcoming of calculations is they are almost never accurate.  That is why in the real world, this is measured.

 

That is also what makes the combat film investigation useful for determining real world relative performance.

 

 

 

The 75deg/s are the steady rate of roll of the Fw190 at 50lb stick force at 10.000ft at 400mph IAS. At these parameters, it is the maximum rate of roll.

 

Those are also narrow parameters.  It is a baseline to compare performance under specific conditions and does not represent individual performance in the air.   Having a gameshape roll at this rate under all circumstances is not how airplanes work.

 

In the British test, the aileron for the FW-190 is not at full deflection for much of the aircraft's envelope.  

 

The maximum rate of roll at 10,000 feet occurs at 350mph EAS:

 

17 degrees aileron deflection  (+ or - 2 Degrees for rigging) * 11 degrees of Rate per Degree of deflection = 187 degrees per second

 

Ballparking the control forces appears to put the maximum rate of roll though at about 187 degrees per second under those conditions which is well above Fig 6 95 degrees a second.  That is eyeballing ~80lbs of input force which is the upper level.  If we drop the velocity even further to ~300 mph EAS of course that rate goes up from 130 degrees per second to ~178.5 degrees per second ~65lbs of control input.

 

 

Ze_Hairy's plot

 

Is for a FW-190 without wing weapons.  RAE 1231 is data from an FW-190 with wing weapons.  It makes a difference.  

 

Removing the wing weapons will increase rate of roll. 

[JtD]

JtD, what's your intuition / educated guess / knowledge on this? Is the acceleration to the steady rate indeed that instatenous in reality (and if not, why wouldn't the report take it into account)? I.e. how big role does inertia, for example, play in all this?

I guess the 0.25 seconds were found as an acceptably accurate figure for the purpose of the test method, but it doesn't need to depict reality in every detail. Roll rate does not go from 0 to 100 instantaneously, due to inertia and aerodynamic damping. Both being fairly important, aircraft specific parameters, which are not investigated in the test.

To get a better idea of Fw190 performance in this regard, I've used this video, specifically the roll at 5:40 to check a bit. Since ailerons and bank angle are visible, this is actually a quite good source on the subject. Judging from bank angle and turn time, I estimate the true airspeed at around 450km/h, close to best rolling speed according to NACA. Unfortunately, there's no way of telling how much aileron is possible, but I'd estimate that he's using about 50%-70% of available range.

I used the very sophisticated ruler-on-the-screen method to track aileron movement and bank angle and came up with attached chart. Roll rate in °/s, aileron input to match the scale, both displayed over time in seconds. It shows a delay between aileron movement and aircraft reaction in the range 0.15-0.2 seconds, showing that in case of the Fw190, the generic RAE figure is on the high side, but still a good match.

[unreasonable]

I guess the 0.25 seconds were found as an acceptably accurate figure for the purpose of the test method, but it doesn't need to depict reality in every detail. Roll rate does not go from 0 to 100 instantaneously, due to inertia and aerodynamic damping.

 

Indeed: my take is that the 0.25s is just calculating it as though roll-rate starts at zero at the origin, and rises in a straight line until it reaches the steady state at time 0.5s.

 

My guess would be that if you could plot roll rate accurately over time in the first 0.5 seconds you would get an S curve but the "area under the curve" might be the same as a straight line.

 

OTOH, if the curve shoots up at about the 0.25 second mark (but 0.5s is correct), as in one of Crump's diagrams, then the RAE number (0.25s) is too high. Estimating a straight line from 0.25 secs instead of the origin

gives you a 0.125 sec lag to create the same area (ie roll), instead of 0.25, but this is now probably an underestimate: some of the curve will be above the straight line.  (Wish I could do graphs on PC more easily, much easier to explain what I mean).

 

Splitting the difference gives a  0.1875s lag, ie 0.0625 seconds different to RAE.  This is equal to only 4.7 degrees difference at the 75 degree/s roll rate. You could do a calculation with much more accuracy, but what is the point if your measurements are not that accurate and consistent? We are now down to talking about hundreths of a second and a few degrees.

Edited January 29, 2016 by unreasonable

[Crump]

 

 

To get a better idea of Fw190 performance in this regard, I've used this video, specifically the roll at 5:40 to check a bit. Since ailerons and bank angle are visible, this is actually a quite good source on the subject. Judging from bank angle and turn time, I estimate the true airspeed at around 450km/h, close to best rolling speed according to NACA. Unfortunately, there's no way of telling how much aileron is possible, but I'd estimate that he's using about 50%-70% of available range.

 

 Are you being funny or serious? 

[JtD]

Three pages in this topic and it's the only measured data on Fw190 roll acceleration posted. As soon as something better comes up, I'll be laughing, but in the meantime, I'm serious.

[MiloMorai]

Nice video JtD. Shows that the A-8 can fly without having the outer cannons installed or any cannon installed, despite what some experts say.

[Dr_Molenbeek]

Nice video JtD. Shows that the A-8 can fly without having the outer cannons installed or any cannon installed, despite what some experts say.

 

You really have meet people who said that ? Wow...

[LukeFF]

You really have meet people who said that ? Wow...

 

Crump is one who claims that. 

[Crump]

Nice video JtD. Shows that the A-8 can fly without having the outer cannons installed or any cannon installed, despite what some experts say.

 

 

That is not an FW-190A8.....

Three pages in this topic and it's the only measured data on Fw190 roll acceleration posted. As soon as something better comes up, I'll be laughing, but in the meantime, I'm serious.

 

 

Ok, your "investigation" is amateurish and extremely silly.  I can only conclude it is simply flamebait.

[Crump]

You really have meet people who said that ? Wow...

 

 

 

The Type I thru Type IV loadouts are the configuration that the Geschwader level is allow to change.  Everything else is a factory level modification.

 

That is how it works in the Luftwaffe regulations.

[JtD]

Ok, your "investigation" is amateurish and extremely silly.  I can only conclude it is simply flamebait.

The quality of my measurements can best be judged when repeating them, and the quality of my results when other data becomes available. I'm pretty sure you've just jumped to your conclusion without either.

Edited February 7, 2016 by JtD

[Crump]

The quality of my measurements can best be judged when repeating them, and the quality of my results when other data becomes available. I'm pretty sure you've just jumped to your conclusion without either.

 

Attempting to extrapolate maximum performance lateral control data solely from a GoPro attached to a vertical stab is silly exercise and not worth discussing.

[JtD]

Well, my point wasn't maximum performance lateral control but roll acceleration characteristics.

[Crump]

Well, my point wasn't maximum performance lateral control but roll acceleration characteristics.

 

You cannot get that information from just a gopro strapped to a vertical stab......

 

Why would you even think that was worth discussing??

[JtD]

You cannot get that information from just a gopro strapped to a vertical stab......

Well, I already did, so now is a bit late to claim that I can't, isn't it? Anyway, if you disagree with the data, you're welcome to provide better and that's really all I can say about that. Edited February 7, 2016 by JtD

[Crump]

 

 

I used the very sophisticated ruler-on-the-screen method to track aileron movement and bank angle

 

  

[unreasonable]

To be fair, ruler on the screen is all the RAE analysts could have done in assessing the gun camera footage to come up with figure 5. 

[Crump]

To be fair, ruler on the screen is all the RAE analysts could have done in assessing the gun camera footage to come up with figure 5. 

 

 

To be fair that is not at all what they did.....

 

Nor was the purpose of their investigation to determine the instantaneous roll rate of the FW-190.  

[unreasonable]

To be fair that is not at all what they did.....

 

Nor was the purpose of their investigation to determine the instantaneous roll rate of the FW-190.  

 

If that is not what they did to produce Fig 5 as my original post asserts,  then pray enlighten us. 

 

All the report says is that some interesting camera gun pictures had been obtained of banking Fw190s, from which Fig 5 had been produced.

 

The obvious conclusion is that the analyst simply drew a straight line through the wingtips using a ruler, and measured the angle from a baseline using a protractor, taking frame at a time (or some interval of frames). The results were then plotted and smooth lines extrapolated to get Fig 5.

 

It is hard to see what else could have been done with photographs - but if you know better please tell us.

 

As to their purpose - irrelevant. The issue is whether the information contained in the report - or obtained using ruler on the screen methods in game - is useful to us in determining whatever it is we wish to determine.

[MiloMorai]

The video can't be used for any math as we have been told it is not a real Fw190A-8.

[Crump]

Well, I already did, so now is a bit late to claim that I can't, isn't it? Anyway, if you disagree with the data, you're welcome to provide better and that's really all I can say about that.

 

 

You simply looked at film with the idea to determine instantaneous roll rate.

 

 

I used the very sophisticated ruler-on-the-screen method to track aileron movement and bank angle and came up with attached chart. Roll rate in °/s, aileron input to match the scale, both displayed over time in seconds. It shows a delay between aileron movement and aircraft reaction in the range 0.15-0.2 seconds, showing that in case of the Fw190, the generic RAE figure is on the high side, but still a good match.

 

 

 

What you did not grasp is the instantaneous roll rate is a function of stick input.  The RAE assumes 1/4 seconds of instantaneous acceleration with a 50lb control input.  You have no way of knowing the control input.  There is nothing to be measured in your analysis and it is total nonsense.

 

I tried to send you a PM concerning this but was unable to. You need to be mindful of how you converse with folks.

 

 

It has nothing to do with Figure 5 or the RAE gun camera investigation.  

 

The RAE was simply recording the relative performance observed in combat.

 

 

Edited February 8, 2016 by Bearcat

[Crump]

Nice video JtD. Shows that the A-8 can fly without having the outer cannons installed or any cannon installed, despite what some experts say.

 

 

Are you always going to continue this nonsense or are you man enough to admit you are wrong.  The load plan simply does not allow for the Operator to remove the outboard cannon in the basic service fighter variant of the FW-190A5 and above.

 

http://forum.il2sturmovik.com/topic/17974-la-5-vs-fw-190a-3-roll-rate-comparison/page-3?do=findComment&comment=330847

 

That is a fact Milo.  Throwing up exceptional and unknown circumstance photographs or third party claims without evidence is not proof the Focke Wulf GmbH and Luftwaffe documentation is not correct.

Those documents I posted are in the Operating Instructions.

[JtD]

You have no way of knowing the control input.

Well, I demonstrated I do by looking at aileron movement, so now is a bit late to claim that there's no way, isn't it?

Edited February 8, 2016 by JtD

[MiloMorai]

Are you always going to continue this nonsense or are you man enough to admit you are wrong.  The load plan simply does not allow for the Operator to remove the outboard cannon in the basic service fighter variant of the FW-190A5 and above.

 

http://forum.il2sturmovik.com/topic/17974-la-5-vs-fw-190a-3-roll-rate-comparison/page-3?do=findComment&comment=330847

 

That is a fact Milo.  Throwing up exceptional and unknown circumstance photographs or third party claims without evidence is not proof the Focke Wulf GmbH and Luftwaffe documentation is not correct.

Those documents I posted are in the Operating Instructions.

 

LOL that is quite something with you wanting me to man up when you are the master of not doing so. Where was the 9th AF based in 1944, or how about the aux fuel tank being installed/removed in the A-8 depending on the mission to be flown, or 100 fuel in the BoB, or the use of 150 fuel. One could go on forever......

 

Early versions of the Fw190A-8/R6 had the outer cannons removed and flew when the rocket tubes were jettisoned. Even the Mistel/Fw190 flew with cannons removed. So give it up and admit the Fw190A-8 could be flown with cannons removed.

[Crump]

 

 

Early versions of the Fw190A-8/R6 had the outer cannons removed and flew when the rocket tubes were jettisoned.

 

I am the one that told you that and Rustsatz kits were factory modification kits.  

 

Hence the designation "FW-190A8/R6"......not FW-190A8....but FW-190A8/R6....

 

 

The fact is a standard issue FW-190A5 or later fighter variant could not remove the outboard cannon.  It was not an authorized load out and it certainly was not subject to the pilots whims or desires.

The Mistel FW-190A8 was not a normal fighter variant but a specialized factory variant.  The ladeplans do not cover special factory variants.  They only cover the normal fighter.

[Crump]

Each variant Milo will have a lade plan specifically for that variant.  

 

FW-190A5/U8

 

 

FW-190G3

 

 

 

 

 

Well, I demonstrated I do by looking at aileron movement, so now is a bit late to claim that there's no way, isn't it?

 

 

Read that ten times and see if it still makes a bit of sense.....

[LukeFF]

I'm still trying to figure out how, according to Crump, a 190 A-8 could not fly with its outboard cannons removed, yet at the same time the F-8 - which was essentially just the ground attack model of the A-8 - could and did fly all the time with no outboard cannons.

[Crump]

I'm still trying to figure out how, according to Crump, a 190 A-8 could not fly with its outboard cannons removed, yet at the same time the F-8 - which was essentially just the ground attack model of the A-8 - could and did fly all the time with no outboard cannons.

 

You would understand it easily if you dealt with something other than fantasy airplanes.

An FW-190F8 is NOT an FW-190A8.

 

If it was wouldn't it be really really stupid to call it something different????????

[LukeFF]

Well, that escalated quickly. 

 

Key differences between the F-8 and A-8:

• Outboard cannons removed
• Low altitude boost system installed
• Radio for better air-to-ground communication
• Optional outer-wing bomb racks.

Oh, then there's also this: http://airandspace.si.edu/collections/artifact.cfm?object=nasm_A19600318000

 

This Fw 190 F-8 was originally manufactured as an Fw 190 A-7 fighter. During 1944 it was remanufactured as a fighter-bomber and issued to ground attack unit SG 2.

 

Wow! So, you mean, it was originally an A-series airplane that didn't fall out of the sky once the outboard cannons were removed?   If this one example was a remanufactured A-7, then surely there were other late A-series airframes reworked into F-series planes.

 

C'mon Crump, you can do better than this.

Edited February 8, 2016 by LukeFF

[NZTyphoon]

I am the one that told you that and Rustsatz kits were factory modification kits.

 

Hence the designation "FW-190A8/R6"......not FW-190A8....but FW-190A8/R6....

 

 

Actually, Rüstsätze or "equipment condition" was a factory supplied kit; the aircraft could be modified at front-line airfields, or at depots or at the factory; eg: The 190A-8/R6 was fitted with the WGr 21 rocket launcher under each wing (all A-8s were built with the electrical systems needed for the WGr 21s and for R1, the twin MG 151/20 cannon pods under the outer wings.)

 

Umbausätz were factory only modifications as they require special tooling and were always done at a factory or major overhaul location. These were changes that sometimes required a structural alteration, major alterations to the electrical system or to other systems; eg: the A-8/U1 was the two-seat trainer later called the S-8

Edited February 8, 2016 by NZTyphoon

[NZTyphoon]

The ladeplans do not cover special factory variants.  They only cover the normal fighter.

 

  And yet, one post later, Crump supplies a Ladeplan for the A-5/U8 which was a "special factory variant" (the A-5/U8 was a Jabo-Rei variant, with an ETC 501 rack under the fuselage and four wing racks)

 

Each variant Milo will have a lade plan specifically for that variant.  

 

FW-190A5/U8

 

FW190A5U8 Loadplan.jpg

 

FW-190G3

 

FW190G3Loadplan.jpg

 

 

 

[=362nd_FS=RoflSeal]

Bet Crummp gonna edit that post. Big gaffe to say that R designation was "special factory variant" rather than "field modification kit".

 

Fact is the A-8 could fly with the 2 outer cannons removed, like every other A model, it wouldn't suddenly become impossible to handle.

 

And for it was not an "authorized load", well thank god our pilots and crew chiefs are human and not robots, otherwise they wouldn't ever ever break rules would they? You would never see 2*20mm Hispano jerry rigged on P-47D for ground attack because it was not an "authorized load". Whilst that may be a extreme example another one is the often removal of the 2 outboard MGs on the P-47. It could still fly safely however.

Edited February 8, 2016 by RoflSeal

[6./ZG26_5tuka]

The purpose of the "Ladeplan" is to show how common loadouts effect weight and flight characteristics of the aircraft. Those are listed as "Verwendungszwecke".

 

There's no technical denial of a possible removal of armarment as far as I can see.

 

PS:Ah dang, this nonstop discussion sucked me in...sry Hairy

[Crump]

Actually, Rüstsätze or "equipment condition" was a factory supplied kit; the aircraft could be modified at front-line airfields, or at depots or at the factory; eg: The 190A-8/R6 was fitted with the WGr 21 rocket launcher under each wing (all A-8s were built with the electrical systems needed for the WGr 21s and for R1, the twin MG 151/20 cannon pods under the outer wings.)

 

Umbausätz were factory only modifications as they require special tooling and were always done at a factory or major overhaul location. These were changes that sometimes required a structural alteration, major alterations to the electrical system or to other systems; eg: the A-8/U1 was the two-seat trainer later called the S-8

 

 

 

That has nothing to do with the ladeplan instructions.   Some of the kits could be applied in the field and in all of them once applied, the aircraft designation changed.  Many of them could only be applied at the factory.

 

 

Bet Crummp gonna edit that post. Big gaffe to say that R designation was "special factory variant" rather than "field modification kit".

 

Fact is the A-8 could fly with the 2 outer cannons removed, like every other A model, it wouldn't suddenly become impossible to handle.

 

 

No edit required. Some of the kits could be applied in the field and in all of them once applied, the aircraft designation changed.  Many of them could only be applied at the factory.  It is not a hard fast rule that rüstatz kits are field kits.  Some are major modifications to the aircraft.

 

 

 

And for it was not an "authorized load", well thank god our pilots and crew chiefs are human and not robots, otherwise they wouldn't ever ever break rules would they? You would never see 2*20mm Hispano jerry rigged on P-47D for ground attack because it was not an "authorized load". Whilst that may be a extreme example another one is the often removal of the 2 outboard MGs on the P-47. It could still fly safely however.

 

The rules in aviation are written in blood. 

 

No aviation mechanic is going to modify an aircraft without factory input and engineering data to do so....

 

That is just a fact and anything else is pure gamer fantasy.

 

 

 

And yet, one post later, Crump supplies a Ladeplan for the A-5/U8 which was a "special factory variant" (the A-5/U8 was a Jabo-Rei variant, with an ETC 501 rack under the fuselage and four wing racks)

 

Completely taken out of context and you did it intentionally.

 

"The ladeplans" in my statement "The ladeplans do not cover special factory variants.  They only cover the normal fighter." 

 

........are the first ones I posted for the normal fighter variants.

 

http://forum.il2sturmovik.com/topic/17974-la-5-vs-fw-190a-3-roll-rate-comparison/page-3?do=findComment&comment=330847

 

If the outboard cannon were removable in Rüstatz kit and Umbausatz variants, then they will have a unique ladeplan just for the that variant and it will list that as an authorized load out.

[Crump]

 

 

Well, that escalated quickly.    Key differences between the F-8 and A-8: Outboard cannons removed Low altitude boost system installed Radio for better air-to-ground communication Optional outer-wing bomb racks. Oh, then there's also this: http://airandspace.s...sm_A19600318000

 

Also...Different oil coolers, armour, internal structure, engine peripherals, and bombing equipment (grossebombeneletrik)......

 

Guess what all those changes mean in terms of weight and balance??