Dora roll rate and turning rate, true to real-life data?

[Yo-Yo]

Fairy tale? First of all I was refering to the Dora being cleaner than the Anton, not the P-51. Secondly I don't think that the low CL of the laminar flow airfoil is a fairy tale, all we have is one document from the 40's on scale models and a rather low reynolds number, where'as in the field the P-51's wing couldn't maintain the laminar flow it could in the wind tunnel tests.

 

By sharpening the leading edge of an airfoil and moving back the point of max thickness you will reduce drag significantly, but you WILL also reduce the critical AoA and Clmax. You can't have the best of both worlds in this area.

 

The evidence to back this up are the hard figures we have on the aircraft, the Dora stalls at a lower speed and lands & takes off at lower speeds than the P-51 as well.

 

Hence why the British found no difference in the turning performance between that of an Fw-190 Jabo and P-51B mustang.

 

If you know only one document of so low plausibility (for your mind) it does not mean that there are no docs with the proofs based either on high Mach WT tests or flight tests that low CL for P-51 airfoil is a fairy tale. I have them and if you want you can get them - just begin to search.

[Hummingbird]

If you know only one document of so low plausibility (for your mind) it does not mean that there are no docs with the proofs based either on high Mach WT tests or flight tests that low CL for P-51 airfoil is a fairy tale. I have them and if you want you can get them - just begin to search.

 

Problem is you need data on both airfoils from the same place for it to be a reliable comparison, and even then it's just wind tunnel data, not flight test data.

 

Next there's the actual performance of the wing in real world conditions, and the only way to get accurate figures on that is through flight testing. Hence one needs to look at stall speeds etc.

 

If the Fw190 stalls at a lower speed than the P-51 well then there you have your answer.

[sobek]

What is wrong with wind tunnel data? :)

[GrapeJam]

Problem is you need data on both airfoils from the same place for it to be a reliable comparison, and even then it's just wind tunnel data, not flight test data.

 

Next there's the actual performance of the wing in real world conditions, and the only way to get accurate figures on that is through flight testing. Hence one needs to look at stall speeds etc.

 

If the Fw190 stalls at a lower speed than the P-51 well then there you have your answer.

Considering that at full load 10000lbs the P51D(with wings rack) has a power off stall speed of 106mph IAS clean, and the FW 190D9(in clean conditon) at 8550lbs(meaning no guns no ammo) has a stall speed pf 107mph IAS clean(if A2A is to believe), nope, no way the Dora should outturn the P51D.

[Yo-Yo]

Problem is you need data on both airfoils from the same place for it to be a reliable comparison, and even then it's just wind tunnel data, not flight test data.

 

Next there's the actual performance of the wing in real world conditions, and the only way to get accurate figures on that is through flight testing. Hence one needs to look at stall speeds etc.

 

If the Fw190 stalls at a lower speed than the P-51 well then there you have your answer.

 

It's a new scientific trend, I think... if Re and M are both known, WT data presumed reliable in real world. By the way, I mean not plain airfoil measurements but WT tests with the planes using these airfoils.

 

And yes, the comparative report shows that both WT and flight tests match very well.

 

So, if you want to claim further about "poor P-51 airfoil lift" please provide something better than forums and articles claims.

[Hummingbird]

Considering that at full load 10000lbs the P51D(with wings rack) has a power off stall speed of 106mph IAS clean, and the FW 190D9(in clean conditon) at 8550lbs(meaning no guns no ammo) has a stall speed pf 107mph IAS clean(if A2A is to believe), nope, no way the Dora should outturn the P51D.

 

A2A ?

 

The Fw-190D9 has a landing speed of 167 km/h and a take off run of 365 meters at 4270 kg (9400 lbs) according to German charts.

 

Compare that to the landing speed & take off run of a 8700 lbs P-51D at 167 km/h and 441 meters. (Landing speed at 9400 lbs is 173 km/h)

 

All figures are straight from the manuals.

 

So yeah, something is definitely off ingame.

Edited April 3, 2015 by Hummingbird
Take off distance for P-51D is 441 meters

[GrapeJam]

A2A ?

 

The Fw-190D9 has a landing speed of 167 km/h and a take off run of 365 meters at 4270 kg (9400 lbs) according to German charts.

Sources?

[Hummingbird]

Sources?

 

Focke Wulf AG charts. In Yo-Yo's words, just do a search.

[Hummingbird]

P-51D chart:

[Hummingbird]

Apologies, landing speed of Dora-9 is actually lower still at 165 km/h, not 167 km/h. Same as Fw190A6.

[GrapeJam]

Landing speed =/= stall speed, landing speed can be defined to be higher than necessary for some nation, stall speed on the other hand is absolute.

 

 

And landing speed is absolutely not a reliable way to judge turning ability, the plane in landing configuration has flaps and gears fully down, do you really wanna turn fight in that configuration?

 

Take an example: The Ki 84 has a stall speed of 102mph clean but in landing configuration has a much lower stall speed than the Spitfire IX, of only 78mph but in a test between the two planes in a turn fight combat scenario, even with maneuvering flaps out the Ki84 couldn't outturn the Spitfire.

[Hummingbird]

Landing speed =/= stall speed, landing speed can be defined to be higher than necessary for some nation, stall speed on the other hand is absolute.

 

 

That's IAS though, which will be rather inaccurate. German & US figures I listed are TAS.

 

And landing speed is absolutely not a reliable way to judge turning ability, the plane in landing configuration has flaps and gears fully down, do you really wanna turn fight in that configuration?

 

Take an example: The Ki 84 has a stall speed of 102mph clean but in landing configuration has a much lower stall speed than the Spitfire IX, of only 78mph but in a test between the two planes in a turn fight, even with maneuvering flaps out the Ki84 couldn't outturn the Spitfire.

 

Again you're most likely using IAS figures for that claim. Btw with flaps down and gear up the stall speed will be even lower than with gears down.

 

Also in a turn fight other factors such as the thrust to weight ratio also matters.

Edited April 3, 2015 by Hummingbird

[GrapeJam]

That's IAS though, which will be rather inaccurate. German & US figures I listed are TAS.

 

I'm still waiting for your sources on the FW 190D9's stall speed. A2A is also IAS and it gave 107mph IAS clean stalling speed at 8550lbs. For all we know , the FW 190's landing gears can help it to have more lift than the Mustang. And you're certainly welcome to try to turn fight with landing gears down.

Also in a turn fight other factors such as the thrust to weight ratio also matters.

Both the Ki84 and the Spitfire IX had near identical powerloading. But powerloading only helps in sustaining the turn, not instaneous turn which is what we're talking about.

Btw with flaps down and gear up the stall speed will be even lower than with gears down.

 

I think a huge paradox's just happened.

Edited April 3, 2015 by GrapeJam

[Hummingbird]

I'm still waiting for your sources on the FW 190D9's stall speed. A2A is also IAS and it gave 107mph IAS clean stalling speed at 8550lbs. For all we know , the FW 190's landing gears can help it to have more lift than the Mustang. And you're certainly welcome to try to turn fight with landing gears down.

 

A2A is a game... :huh:

 

Why wait? Just look up the Fw190 charts & manuals.

 

Both the Ki84 and the Spitfire IX had near identical powerloading. But powerloading only helps in sustaining the turn, not instaneous turn which is what we're talking about.

 

There's more to it than power loadings, such as how effective the prop design is, and AFAIK the Ki-84 used a toothpick prop same as those initially used on the P-47 until it was given a larger prop.

[Hummingbird]

I think a huge paradox's just happened.

 

You mentioned that the Ki-84 wasn't able to outmaneuver the Spitfire even with flaps down, well in that case it severely hampered by a lack of thrust because as you said yourself the Ki-84's stall speed was significantly lower than the Spitfire's with flaps & gear down.

 

Leaving flaps down and raising the gear will lower the stall speed even further as drag is reduced and airflow is smoothened under the wing.

 

Oh and btw, no we're not just talking ITR, but obviously also STR as a turn fight usually involves turning past 360 deg.

Edited April 3, 2015 by Hummingbird

[GrapeJam]

A2A is a game... :huh:

 

A2A is a sim, just like DCS, and some would say that A2A is more accurate than DCS.

 

Why wait? Just look up the Fw190 charts & manuals.

Because landing speed -/- stall speed, and nobody turn fight with gears down.

 

There's more to it than power loadings, such as how effective the prop design is, and AFAIK the Ki-84 used a toothpick prop same as those initially used on the P-47 until it was given a larger prop.

Considering that the both planes climb rate are very close, propellers design is out of question.

[GrapeJam]

You mentioned that the Ki-84 wasn't able to outmaneuver the Spitfire even with flaps down, well in that case it severely hampered by a lack of thrust because as you said yourself the Ki-84's stall speed was significantly lower than the Spitfire's with flaps & gear down.

 

 

Leaving flaps down and raising the gear will lower the stall speed even further as drag is reduced and airflow is smoothened under the wing.

 

 

I said the Ki -84 with maneuvering flaps, in combat scenario, couldn't outturn the Spitfire IX. Do you count having landing gears down as combat scenario?

 

Oh and btw, no we're not just talking ITR, but also STR.

STR is more than just powerloading, else the K4 would be able to outturn a Zero in a sustain turn fight. Energy loss during maneuver also play a part, has it ever accured to you that the D9's much higher wing loading will make it lose energy more than it can gain sufficiently in a turn fight with the much lower wing loading Mustang?

[Hummingbird]

A2A is a sim, just like DCS, and some would say that A2A is more accurate than DCS.

 

There have come and gone plenty a sim with inaccurate FMs.

 

Because landing speed -/- stall speed, and nobody turn fight with gears down.

 

In that case just raise the gear. Flaps were often used in combat.

 

Considering that the both planes climb rate are very close, propellers design is out of question.

 

Do you honestly believe that the Ki-84 stalled at 102 mph clean, power off, TAS? That's pretty much the same as the P-51! No way josé.. 102 mph IAS maybe (Japanese speed gauges weren't particularly accurate), but not TAS. The Ki-84 was described as having a turning circle only slightly inferior to the Zero, the P-51 wasn't even close to that.

 

As for the Ki-84 vs Spitfire test, show me plz.

[Hummingbird]

I said the Ki -84 with maneuvering flaps, in combat scenario, couldn't outturn the Spitfire IX. Do you count having landing gears down as combat scenario?

 

Again stop focusing on the landing gear, you can lower the flaps without lowering the landing gear you know, which will lower the stall speed even further than if you lower the gear with it.

 

STR is more than just powerloading, else the K4 would be able to outturn a Zero in a sustain turn fight. Energy loss during maneuver also play a part, has it ever accured to you that the D9's much higher wing loading will make it lose energy more than it can gain sufficiently in a turn fight with the much lower wing loading Mustang?

 

*sigh* has it occured to you that wing loading is a meaningless number without knowing the lift coefficient of the wing?

 

There's a reason the Fw190 can stay in the air at as low speeds as the P-51 without stalling, despite having a smaller wing = it's lift coefficient is higher.

[GrapeJam]

Again stop focusing on the landing gear, you can lower the flaps without lowering the landing gear you know, which will lower the stall speed even further than if you lower the gear with it.

 

Aeroplane Flight Training Manual, Transport Canada, 4th ed, 1999, pg 76:

 

"Extending the landing gear increases drag. The effect on stalling speed

varies from aircraft to aircraft but generally in the classic wings level

nose-up attitude a slightly lower stalling speed will be noted, especially

in the power-on configuration."

 

 

*sigh* has it occured to you that wing loading is a meaningless number without knowing the lift coefficient of the wing?

 

There's a reason the Fw190 can stay in the air at as low speeds as the P-51 without stalling, despite having a smaller wing = it's lift coefficient is higher.

 

High, the question is: is it high enough to compensate for the much higher wing loading?

 

The stall speed in clean configuration answer that question, without guns and ammo the D9 still has higher stall speed than the P51D at full load.

[GrapeJam]

There have come and gone plenty a sim with inaccurate FMs.

 

Yeah, this spec is on their website, and as a sim I'd expect the spec to be what they aspire their FM to.

 

 

In that case just raise the gear. Flaps were often used in combat.

 

Read above.

 

 

Do you honestly believe that the Ki-84 stalled at 102 mph clean, power off, TAS? That's pretty much the same as the P-51! No way josé.. 102 mph IAS maybe (Japanese speed gauges weren't particularly accurate), but not TAS. The Ki-84 was described as having a turning circle only slightly inferior to the Zero, the P-51 wasn't even close to that.

 

"Slightly inferior" is relative. And in case you didn't know the Japanese captured a P51C and during test they also said that the turning characteristic of the P51C is almost the same as the Ki 84.

 

As for the Ki-84 vs Spitfire test, show me plz.

You should ask Hiromachi, the source is from him and as he's Japanese fan I'd take it as believable.

[Hummingbird]

High, the question is: is it high enough to compensate for the much higher wing loading?

 

The stall speed in clean configuration answer that question, without guns and ammo the D9 still has higher stall speed than the P51D at full load.

 

According to who & what? A game? Come on...

[Hummingbird]

Yeah, this spec is on their website, and as a sim I'd expect the spec to be what they aspire their FM to.

 

 

 

 

Read above.

 

 

 

 

"Slightly inferior" is relative. And in case you didn't know the Japanese captured a P51C and during test they also said that the turning characteristic of the P51C is almost the same as the Ki 84.

 

 

You should ask Hiromachi, the source is from him and as he's Japanese fan I'd take it as believable.

 

Yeah as I thought it doesn't exist...

 

The US actually tested the Ki-84 and found it to be a very maneuverable fighter only slightly inferior in the turn to the Zero.

 

Btw, the F4U uses the exact same airfoil as the Fw190, and in US tests it was found to easily outturn the P-51C mustang with a similar wing loading.

Edited April 4, 2015 by Hummingbird

[Hummingbird]

Aeroplane Flight Training Manual, Transport Canada, 4th ed, 1999, pg 76:

 

"Extending the landing gear increases drag. The effect on stalling speed

varies from aircraft to aircraft but generally in the classic wings level

nose-up attitude a slightly lower stalling speed will be noted, especially

in the power-on configuration."

 

This is so misleading that it's frightening.

 

Only lowering the landing gear will NOT lower the stall speed, the stall speed will either stay the same or slightly increase as the extended gear disturbs the airflow on the wing.

 

Hence the stalling speed with only flaps down will normally either be lower than with both flaps and gear down or the same but with reduced drag. Any pilot knows this.

 

Please don't just quote from a google search..

[Solty]

This is so misleading that it's frightening.

 

Only lowering the landing gear will NOT lor the stall speed, the stall speed will either stay the same or slightly increase as the extended gear disturbs the airflow on the wing.

 

Hence the stalling speed with only flaps down will normally either be lower than with both flaps and gear down or the same but with reduced drag. Any pilot knows this.

 

Please don't just quote from a google search..

 

First of all, you still haven't presented any kind of test that would prove anything in turning department.

 

Landing speed is not a good measurement of any kind of turn performance. You are still pulling the same argument just changing your wording.

 

The landing speed is no argument at all. Show us at least stalling speed