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

[msalama]

Propaganda. Human nature being what it is ...what they *knew* and what they made available to the public could be two different things.

 

As it comes to purely technical reports and analysis? Sorry, not buying it. All different when the so-called human factor (characterization of enemy combatants, etc.) comes into play, of course, but pure techie stuff? Nah, not buying it.

[Teapot]

The truth was quite the opposite: ...

 

Unfortunately, the end result is now we have people that grossly over-rate German equipment

 

So you say, and you're welcome to your opinion. :)

 

As it comes to purely technical reports and analysis? Sorry, not buying it. All different when the so-called human factor (characterization of enemy combatants, etc.) comes into play, of course, but pure techie stuff? Nah, not buying it.

 

That's ok too ... and as you can see there appears to be no shortage of *opinion* fielded on either side of the debate!

Edited April 14, 2015 by Teapot

[NineLine]

The truth was quite the opposite: with the Soviets and Western Allies facing off against each other in the cold war, *both* sides lionized the Germans as a propaganda tool. By making the Germans look stronger than they had actually been (in numbers, martial prowess, and quality of equipment), it made the forces that defeated the Germans look stronger, too.

 

The idea seems to have been "we beat the Germans, and they were WAY stronger than those dirty reds/ filthy capitalists, so those guys will be pushovers".

 

Why do you think there was such a spate of war movies in the 40s-50s?

 

Unfortunately, the end result is now we have people that grossly over-rate German equipment

 

 

Ok... we are really starting to drift now... stay on topic please.

[Hummingbird]

Source if you will, please.

 

Already provided. Take off distance at Steig u. Kampfleistung was 365 m, as such the min take off at Start u. Notleistung would be around 310 m, maybe even lower. See Fw190A8 manual for reference.

[[DBS]TH0R]

Yes, let us get back to the topic.

 

Earlier here Hummingbird posted some values. His starting arguments were:

 

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.

 

To be more precise:

 

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.

 

&

 

Here are the actual take off distances:

 

Take off distance on concrete is 365 m for the Dora and 430 m for the A-8, and 570 meters for the Dora to clear 20 m height.

 

Since my German is rough at best, I revered to the available P/F-51 manuals i.e. primary sources Hummingbird claimed to have read.

 

Already in post #185 I had a hunch something was off with the values and how Hummingbird presented them.

 

First I supplied a link to the P-51D pilots notes in post #174. Now I had a look at the available F-51D Flight Handbook here:

 

http://www.avialogs.com/en/aircraft/usa/northamericanaviation/p-51mustang/an-01-60je-1-flight-handbook-f-51d.html

 

 

Lets start with p. 37 (document page 31):

 

4. Flaps:

Flaps set for take-off (UP for normal take off).

 

... and on the following page:

 

TAKE-OFF.

See figure A-4 for required take-off distances.

 

By looking at the figure A-4 on p.109/110 (document page 103/104):

 

- Values closest to the standard atmosphere +15° Centigrade / ZERO WIND @ Sea Level and hard surface runway:

 

GROSS WEIGHT | GROUND RUN | TO CLEAR 50ft OBST.

 

9000 LB (~4082kg) | 1000ft (~305m) | 1750ft (~533m)

10000 LB (~4536kg) | 1250ft (~381m) | 2100ft (~640m)

 

On the bottom of the page it says clearly:

 

REMARKS:

1. Take-off distances are aircraft requirements under normal service conditions.

2. Take-off power, 3000 rpm 61 in. Hg.

3. Flaps up.

 

Now lets get back to p.38 (document page 32) and look again at the 3 pages GrapeJam originally showed in post #159 which features values for a take off with flaps down 15-20 degrees:

 

GROSS WEIGHT | GROUND RUN | TO CLEAR 50ft OBST.

 

10000 LB (~4536kg) | 1100ft (~335m) | 2100ft (~564m)

 

 

Between flaps up and down, at 10000LB the difference is ~46m!

 

I have no intention of speculating the appropriate ground run distance for the equivalent P-51D weight of 4300kg and a ground run of 365m on "beton runway" Hummingbird posted here for Fw-190D9. However, in the light of the "normal take-off procedures" shown in the F-51D Flight Handbook, by looking at this source:

 

http://www.wwiiaircraftperformance.org/mustang/p-51d-na-46-130.html

 

We can see that at the gross weight of 9611lb (~4360kg) take-off (no wind) ground run equals 1040 ft (~317m) - and fits plausibly in between available values listed above.

 

I don't know if Fw-190 manual states flaps must be used on take off or not, but by all accounts they should. All in all that is a whooping ~48m shorter ground run distance than Fw-190D9 shown in the figures above, and presumably without flaps.

 

 

Already provided. Take off distance at Steig u. Kampfleistung was 365 m, as such the min take off at Start u. Notleistung would be around 310 m, maybe even lower. See Fw190A8 manual for reference.

 

Thank you. That is ~55m difference in contrast to ~46m for the Mustang. With the available info here, I think you will agree that it is plausable P-51D's minimal TO distance with flaps will be below 310m with the starting one at the roughly same weight being ~317m.

 

 

In short, you need to revise your CL figures for the P-51, unless ofcourse you want us to fly around in one with carefully filled, waxed & polished wings vs aircraft with wings in rough operational field conditions :D

 

Airfoils and planes are not my expertise, but I am am an mechanical engineer by profession. And I know that you need to look at the problem from various angles, i.e. all variables are important. Seeing how this is the second time you have cherry picked values that suite your arguments, I will place my faith in Yo-Yo's FM / CL figures.

Edited April 14, 2015 by T}{OR
10000, not 1000 | 4300, not 9300

[GrapeJam]

Already provided. Take off distance at Steig u. Kampfleistung was 365 m, as such the min take off at Start u. Notleistung would be around 310 m, maybe even lower. See Fw190A8 manual for reference.

 

In the A8's pilot manual, the plane takes off with flaps in take off position, does your chart have the planes take off with flaps in neutral or take off position?

[Crumpp]

Grapejam,

 

Check the source of the turning circle chart you posted. It is from a post war enthusiasts magazine and is based on pilot recollection.

 

According to Focke Wulf the Clmax for the FW190 wing is 1.58. Thst gives spot on agreement with the NACA airfoil data and Clmax for the wing in their own investigation.

 

The P51D is very close to that at 1.51.

[Hummingbird]

I haven't been cherry picking anything T}{OR.

 

Look at the P-51D tactical chart again, nowhere is it mentioned that take off distances are without flaps: http://www.wwiiaircraftperformance.org/mustang/p-51-tactical-chart.jpg

 

Also taking a look inside the P-51D manual on page 70: http://www.wwiiaircraftperformance.org/mustang/P-51D-manual-5april44.pdf

 

You'll note a regular take off distance at 9,000 lbs of 1400 ft (426 m) and 2000 ft (609 m) to clear a 50 ft object. No mention of flaps being up.

 

As for absolute minimum (or optimum) take off distances at 3000 rpm & 20 deg flaps (page 78) specifies that the P-51D & K needs 1120 feet (341 m) to take off and 1600 ft (426 m) to clear a 50 ft (15 m) object.

 

By comparison the Fw190D-9 features a regular take off distance at 9480 lbs and Steig u. Kampfleistung of 1197 ft (365 m) and 1870 ft (570 m) to clear a 65 ft (20 m) object.

[Hummingbird]

Grapejam,

 

Check the source of the turning circle chart you posted. It is from a post war enthusiasts magazine and is based on pilot recollection.

 

According to Focke Wulf the Clmax for the FW190 wing is 1.58. Thst gives spot on agreement with the NACA airfoil data and Clmax for the wing in their own investigation.

 

The P51D is very close to that at 1.51.

 

But where does this 1.51 CLmax come from?

 

Highest I could get for a filled, waxed & polished wing is 1.47.

[GrapeJam]

I haven't been cherry picking anything T}{OR.

 

Look at the P-51D tactical chart again, nowhere is it mentioned that take off distances are without flaps: http://www.wwiiaircraftperformance.org/mustang/p-51-tactical-chart.jpg

 

You're aware that this is the tactical chart for commander planning right? It should cover every possible configuration.

 

Also taking a look inside the P-51D manual on page 70: http://www.wwiiaircraftperformance.org/mustang/P-51D-manual-5april44.pdf

 

You'll note a regular take off distance at 9,000 lbs of 1400 ft (426 m) and 2000 ft (609 m) to clear a 50 ft object. No mention of flaps being up.

 

As for absolute minimum (or optimum) take off distances at 3000 rpm & 20 deg flaps (page 7 specifies that the P-51D & K needs 1120 feet (341 m) to take off and 1600 ft (426 m) to clear a 50 ft (15 m) object.

 

You're not cherry picking anything alright.

 

And yeah, the handbook from march 1944 is should definitely be more accurate than revised editions published in 1952 and 1955, and not by the country of origin, and said country kept their planes so well that the Mustang IV only managed to reach 354 mph TAS at SL instead of 375 TAS in American Test.

 

Never mind that the P51D-5 is quite a bit different from the later P51D block that we have in game.

 

 

 

By comparison the Fw190D-9 features a regular take off distance at 9480 lbs and Steig u. Kampfleistung of 1197 ft (365 m) and 1870 ft (570 m) to clear a 65 ft (20 m) object.

 

Flaps up or take off flaps?

[[DBS]TH0R]

Look at the P-51D tactical chart again, nowhere is it mentioned that take off distances are without flaps: http://www.wwiiaircraftperformance.org/mustang/p-51-tactical-chart.jpg

 

And no where is it mentioned they are with. So who do we trust? Since in the F-51D link I posted it clearly states its values are with flaps up, from a plethora more variables clearly defined.

 

 

Also taking a look inside the P-51D manual on page 70: http://www.wwiiaircraftperformance.org/mustang/P-51D-manual-5april44.pdf

 

You'll note a regular take off distance at 9,000 lbs of 1400 ft (426 m) and 2000 ft (609 m) to clear a 50 ft object. No mention of flaps being up.

 

As for absolute minimum (or optimum) take off distances at 3000 rpm & 20 deg flaps (page 78) specifies that the P-51D & K needs 1120 feet (341 m) to take off and 1600 ft (426 m) to clear a 50 ft (15 m) object.

 

Pages 70 and 78 are not available in the link above. Instead, I see similar charts that "hold" your arguments and feature two different engines, V-1650-3 and V-1650-7. Yet the results are worse for a more powerful -7...

[[DBS]TH0R]

You're aware that this is the tactical chart for commander planning right? It should cover every possible configuration.

 

^^I am inclined to agree with this.

 

This document from Aug 1945. also uses the same chart, p.95:

 

http://www.avialogs.com/viewer/avialogs-documentviewer.php?id=3842

 

And it says there: "The take off and landing charts can be used in determining runway distances required".

 

It also says on the following page: "Remember: figures are approximate, always allow for a margin of safety."

 

I know the above is speculation but there is no mention of flaps on TO, not even in the after TO checklist in this document.

 

 

EDIT: Looking again at the link Hummingbird provided, the only mention of flaps is at the bottom right of the V-1650-3 engine chart values. If I read it correctly it says:

 

"OPTIMUM TAKE OFF WITH 3000 RPM. 61 IN.HG. X 20 DEG. FLAP IS YYY OF CHART VALUES". I can not make out what does X & YYY stand for, &, BOS, 80% or something else...

 

Now I do not wish to catch at straws here, but you have to admit that this is not even remotely defined as the data from F-51D Flight Handbook.

Edited April 14, 2015 by T}{OR
Document date

[ArkRoyal]

I haven't been cherry picking anything T}{OR.

 

Look at the P-51D tactical chart again, nowhere is it mentioned that take off distances are without flaps: http://www.wwiiaircraftperformance.org/mustang/p-51-tactical-chart.jpg

 

Also taking a look inside the P-51D manual on page 70: http://www.wwiiaircraftperformance.org/mustang/P-51D-manual-5april44.pdf

 

You'll note a regular take off distance at 9,000 lbs of 1400 ft (426 m) and 2000 ft (609 m) to clear a 50 ft object. No mention of flaps being up.

 

As for absolute minimum (or optimum) take off distances at 3000 rpm & 20 deg flaps (page 78) specifies that the P-51D & K needs 1120 feet (341 m) to take off and 1600 ft (426 m) to clear a 50 ft (15 m) object.

 

By comparison the Fw190D-9 features a regular take off distance at 9480 lbs and Steig u. Kampfleistung of 1197 ft (365 m) and 1870 ft (570 m) to clear a 65 ft (20 m) object.

 

So what? Are we just supposed to assume that they are with flaps then because it suits you? I Guess the longer takeoff distances are because gravity was higher on that day....

[Hummingbird]

Ugh.... read the damn charts people, this is getting ridiculous :rolleyes:

[NineLine]

Ugh.... read the damn charts people, this is getting ridiculous :rolleyes:

 

I would have to agree... Next time, lets try and stick to the topic.