Dora climb rates

[Yo-Yo]

Perhaps I misunderstand your last post? But in my test I got 5000-4600fpm all the way up to 12000ft, airspeed increasing the entire time. I am not referring to a chart, unless you mean what I am comparing it to, which is the tests where 21-22m/s is shown for 1.8 ata. Anyhow Bed. 6am. I will respond later to whatever you reply with.

 

I referred to the chart I can clearly see the power rating and aircraft GW.

http://forums.eagle.ru/attachment.php?attachmentid=111633&d=1421643491

 

THis chart stated that at 3000 rpm rate the initial climb rate is 17.5 m/s. THe SL power is only 1600 ps vs 2100 ps at 1.8 (see engine chart). I wonder how 2100 ps vs 1600 gives so small difference...

[Yo-Yo]

http://www.wwiiaircraftperformance.org/fw190/Fw_190_D-9_C3.pdf

 

In this test is the C3 fuel running at 2.02 ata, in this test the Dora climbs to 9km in 9.5 minutes, the in game Dora(supposedly limited to 1.8 ata) can climb to 9km in 7 minutes 30 seconds, if the FM's accurate how is this possible?

 

Ok, then please quote me the mass of the plane tested...

 

By the way, what is this 2 ata? All graphs for Sonder-Notleistung give the first knee at 100 m that is a sign of 1.8 ata regarding ram pressure at 300 kph. And if it's C3 w/o MW-50 it gives less power than B4 with MW-50.

 

And for me this doc seems to be calculated performance not real tests.

Edited January 19, 2015 by Yo-Yo

[GrapeJam]

Ok, then please quote me the mass of the plane tested...

 

By the way, what is this 2 ata? All graphs for Sonder-Notleistung give the first knee at 100 m that is a sign of 1.8 ata regarding ram pressure at 300 kph. And if it's C3 w/o MW-50 it gives less power than B4 with MW-50.

 

The D9 in the C3 test has the same speed as the D9 tested at 2.02 at SL.

 

[Kwiatek]

MAby these could be usefull:

[Yo-Yo]

Don't you think that this graph contradicts to the graphs you quoted?

17.5 m/s for 3000 rpm Steig-Kampfleistung?

 

http://forums.eagle.ru/attachment.php?attachmentid=111633&d=1421643491

Edited January 19, 2015 by Yo-Yo

[Crumpp]

I just tried 3000 rpm (1.45 ata at SL) climb. For 6 km I have 6 min 46 s or 6.75 min starting from 50 m absolute altiude and 15C SL temperature. There is no difference with the curve on the chart. So, the model matches the data at certain power rate, so if the power rate is increased he climb rate will match the real plane even if there is no certain data for this rate.

 

Exactly...tried to explain that you can go from a known point pretty easily if you know what you are doing.

 

On my quick test, I started at 100 meters and although the indicated altitude was 6Km, the F2 altitude read several hundred meters lower. I figured the atmosphere was not standard or my Kollsman window was just set wrong. Anyway, once I saw it gave good agreement at a known point, I knew the rest was probably right.

Edited January 19, 2015 by Crumpp

[Yo-Yo]

Exactly...tried to explain that you can go from a known point pretty easily if you know what you are doing.

 

On my quick test, I started at 100 meters and although the indicated altitude was 6Km, the F2 altitude read several hundred meters lower. I figured the atmosphere was not standard or my Kollsman window was just set wrong.

 

Never saw this thing...

[Crumpp]

Never saw this thing...

 

I just looked at the track. Pressing F2 gives you a speed, altitude, and time read out. When the Altimeter is at 100 meters, the F2 altitude reads 50 meters, at 1000 meters, the altitude is the same but at 6000meters indicated altitude, the F2 altitude reads ~400 meters low. It is over water so it is not AGL as I first thought.

 

Is that instrumentation position error or is something going on with the atmospheric model?

[Yo-Yo]

To get rid of confusing data and estimate the Vy a litle math is supplied. Crumpp, as far as I remember, figured out the way it could be done - knowing mass, climb speed, L/D ratio, engine power and prop efficiency it's possible to calculate Vi. If there is a case of known Vi, prop efficiency or/and L/D ratio can be agjusted.

 

The first case is the only one well determined flight test for 4100 kg and 1600 ps (Steig-Kampfleistung).

 

THe calculation of excessive power for 4100 kg gives 17.7 m/s corresponding with the chart with 0.8 prop efficiency and L/D=14. Speed was taken 290 kph.

Start-Notleistung is 1780 ps (sometimes 1750, but it does not really matter). Using the same L/D and efficiency the calculation gives 20 m/s for 4100 but 19 m/s for 4300.

Then 4300 kg plane with Sonder-Notleistung 2100 ps gives 23.6 m/s.

[Yo-Yo]

I just looked at the track. Pressing F2 gives you a speed, altitude, and time read out. When the Altimeter is at 100 meters, the F2 altitude reads 50 meters, at 1000 meters, the altitude is the same but at 6000meters indicated altitude, the F2 altitude reads ~400 meters low. It is over water so it is not AGL as I first thought.

 

Is that instrumentation position error or is something going on with the atmospheric model?

 

Could see 180 m difference between F2 and th altimeter at 10000 m.

[Crumpp]

Could see 180 m difference between F2 and th altimeter at 10000 m.

 

Right. Because it kept changing, I thought it was AGL but over the water it does the same thing and the difference between Indicated Altitude and F2 altitude is not constant.

 

Maybe it is AGL and it thinks it is over mountains when the visual shows water?

 

I just pointed it out because as you know, a little slip of the keyboard on a density value can mess a lot of hard work up.

[Solty]

To get rid of confusing data and estimate the Vy a litle math is supplied. Crumpp, as far as I remember, figured out the way it could be done - knowing mass, climb speed, L/D ratio, engine power and prop efficiency it's possible to calculate Vi. If there is a case of known Vi, prop efficiency or/and L/D ratio can be agjusted.

 

The first case is the only one well determined flight test for 4100 kg and 1600 ps (Steig-Kampfleistung).

 

THe calculation of excessive power for 4100 kg gives 17.7 m/s corresponding with the chart with 0.8 prop efficiency and L/D=14. Speed was taken 290 kph.

Start-Notleistung is 1780 ps (sometimes 1750, but it does not really matter). Using the same L/D and efficiency the calculation gives 20 m/s for 4100 but 19 m/s for 4300.

Then 4300 kg plane with Sonder-Notleistung 2100 ps gives 23.6 m/s.

How it is possible then that it took me 7:30min to go from 200m to 9000m? Mybe MW50 boost with 1.8ata is broken? Have you tried that?

 

If its climb rate was around 23m/s it would not leave P-51D in the dust in vertical maneuvering. Right now, when at low speed, the Fw190D9 can just go into vertical and enter a climb that P-51 cannot keep up with.

 

All my tests were made at full power(MW50 ON). 100% fuel and 100% ammo.

 

 

Edited January 19, 2015 by Solty

[Yo-Yo]

How it is possible then that it took me 7:30min to go from 200m to 9000m? Mybe MW50 boost with 1.8ata is broken? Have you tried that?

 

 

Why it should not?

[USARStarkey]

Why it should not?

 

Because the Germans say it took almost 11 minutes.......

 

All of the graphs show the Dora getting 21-22m/s....not 25.4........and it certainly is sustaining 22m/s all the way up to 11000ft.

[USARStarkey]

Additionally, stuff by pilum:

 

Alt(Km) v true(Km/h) v ind(Km/h) climb(m/s) climb (fpm)

 

0.00 298.74 298.74 22.65 4470.28

0.10 299.83 298.44 22.60 4461.40

0.20 300.94 298.14 22.55 4450.97

0.30 302.07 297.84 22.51 4442.17

0.40 303.21 297.54 22.45 4431.09

0.50 304.37 297.25 22.40 4421.08

0.60 305.55 296.95 22.34 4409.50

0.70 306.75 296.65 22.29 4399.58

0.80 307.97 296.35 22.23 4388.08

0.90 309.21 296.05 22.18 4378.26

1.00 310.46 295.75 22.13 4366.85

1.10 311.63 295.45 22.08 4356.93

1.20 312.81 295.15 22.02 4345.40

1.30 314.02 294.86 21.97 4335.58

1.40 315.24 294.56 21.91 4324.13

1.50 316.48 294.26 21.68 4279.53

1.60 317.74 293.96 21.34 4212.49

1.70 319.02 293.66 21.00 4145.47

1.80 320.33 293.36 20.79 4103.06

1.90 321.65 293.06 20.63 4071.60

2.00 323.00 292.76 20.53 4052.40

2.10 324.24 292.47 20.46 4038.63

2.20 325.51 292.17 20.38 4023.18

2.30 326.79 291.87 20.31 4007.78

2.40 328.09 291.57 20.25 3996.30

2.50 329.42 291.27 20.20 3985.89

2.60 330.77 290.97 20.13 3973.76

2.70 332.14 290.67 20.08 3963.46

2.80 333.53 290.37 20.03 3953.23

2.90 334.95 290.08 19.97 3941.26

3.00 336.39 289.78 19.92 3931.14

[Isegrim]

9000m/7.5 minutes = 1200m per minute

 

1200 m per Minute / 60 seconds = 20 m/s

Edited January 19, 2015 by Isegrim

[Pilum]

Some numbers I get from the C++ simulation for the Fw190D9: I'm assuming 4270 kg T/O weight and taking fuel burn in the climb into account in the climb time estimates. Also, I'm testing out two different propeller models so that is why I have two sets of estimates:

 

Sea level climb rate at Steig&Kampfl. (1600 hp) : 15.8 m/s low estimate, 17.2 m/s high estimate.

 

Sea level climb rate at 1.8 ata Sonder Notl. (2100 hp) : 22.65 m/s low estimate, 23.65 m/s high estimate.

 

So while one is a bit more optimistic than the other and perhaps both on the high side, the delta between 1600 and 2100 hp sea level climb rate I get is no more than 6.4-6.8 m/s.

 

Climb time from sea level to 6 Km altitude at Steig & Kampfl.: 6.8 min low estimate, 7.2 min high estimate. (Minute estimates in decimal form)

 

Climb time from 0.2 Km to 9 Km at 1.8 ata Sonder Notl.: 9.6 min low estimate, 9,8 min high estimate.

 

So to me it looks like both the K4 and Dora climb numbers in DCS are a bit optimistic right now. Could it be that the Dora FM is OK but that there is some issue with the power modeling Yo-Yo? IIRC you said that there was such an issue with the Me109K4 and perhaps the same issue now also has impacted the Dora so that the power modeling for both aircraft need to be tuned?

Edited January 19, 2015 by Pilum
Clarified condition for climb time estimates

[Pilum]

I was hoping that this climb issue would be quietly fixed in the latest patch but unfortunately it looks like it's still there:

 

I just did a climb test with the DCS Dora at 1.8 ata with MW50 and climbed from 200m to 9 Km in just 7.5 minutes. This is also close to what a number of different forum members measured before the patch so it looks like nothing has been changed.

 

Since this is even higher than the 9.19 minutes historic data indicates for 2.02 ata it looks like the DCS Dora is still climbing too fast at 1.8 ata.

[Narushima]

Did any one of you claiming the Dora climbs too fast even bothered to check the weight of the DCS Dora?

[Pilum]

Did any one of you claiming the Dora climbs too fast even bothered to check the weight of the DCS Dora?

 

Well with the DCS T/O weight of 4175 Kg with 100% fuel and ammo (Is that planned to be changed BTW?) as opposed to the "real" weight of 4270 Kg the climb time is only reduced by about 22 s in my simulation:

 

Climb time from 0.2 to 9 Km at 1.8 ata Sondernotlesitung with T/O weight 4175 Kg circa 9.45 min.

 

So the current DCS climb time of 7.5 min under the same conditions still seems very optimistic.

[IvanK]

Yes it does....do you wonder why Yo-Yo just post's a chart and leaves your thread without comment?

 

First of all the published climb rates are not at power setting that is pushing the engine to its maximum. They are at the engines climb rating setting.

 

The basic relationship for best climb is Best Rate of Climb = [(Power Available - Power Required)] divided by weight. It occurs at the point [(Power Available - Power Required)] is maximized in propeller aircraft.

 

It is basically power available to weight.

 

That is speed (Vy) that will not change very much. Not enough to make a real difference because the majority of it is a function of the Lift to Drag ratio which IS fixed by the design. In jets, Best Rate of Climb is the speed of L/Dmax. Might be a good time to check your refrences.

 

Fixed by design means you have to do physical changes to the shape of the aircraft to change it. It is like moving the Neutral Point to change CG limits....it does not happen without physical changes to the shape of the design.

 

So, if the engine is making the power it should and our L/D ratio is correct, the game will match the performance of the real thing at its normal climb settings.

 

That means climbing at Vy or best rate speed and climb power setting on the engine.

 

Add more power for Sondernotleistung in the math and we can move from known to unknown to put a pretty good ballpark on where it should be for climb performance.

 

The percentage variation over a mean for climb performance can also be very large when compared to level speed variation.

 

If a problem is present, it will be much easier to track down and fix. If no problem is present then you have learned something about airplane performance so you are not like most folks reading a report and drawing the wrong conclusions.

 

" In jets, Best Rate of Climb is the speed of L/Dmax."

 

Since when ? its always going to be faster, L/D max will pretty much give you best angle

Edited January 28, 2015 by IvanK

[Crumpp]

You are right Ivank.

 

It does not change the conclusion or the fact climbing at the aircraft's published Vy and climb power rating can easily confirm data. You can even use a dimensionless Pw ratio and Velocity ratio or differentiate CD/Cl^2/3 for example.

 

There is a number of techniques to determine the performance with the additional power.

 

There is no published flight data at 1.8ata for the Dora. It is not that hard to run the math for the additional power.

 

I think Yo-Yo has a handle on it. :thumbup:

[otto]

Yo-Yo told us the 109 climb rate is indeed to high .I think he would have posted if the d9's climb rate was also too high. Just my 2 cents.

[Pilum]

I just tried out the DCS Dora climb time from sea level to 9000 m at 1.8 ata in the latest release 1.2.15 and it still seems to be the same climb time, i.e. 7 min 45 s.

This can be compared to the IRL data of 9.19 min for 2.02 ata (See 7th row in first table below):

 

 

This is also in good agreement with an alternative method estimate of 9.2 min based on eyeballing the average climb time from the attached chart which AFAIK is for Sondernotleistung 2.02 ata.

 

Both these figures indicate that the DCS Dora climb rate at 1.8 ata is higher than the IRL data for 2.02 ata.

 

So based on the above, I think it is proven that the Dora climb rate in DCS at 1.8 ata is currently way to high in comparison to historical data and it therefore seems appropriate to move this thread to the bug section.

[Yo-Yo]

I just tried out the DCS Dora climb time from sea level to 9000 m at 1.8 ata in the latest release 1.2.15 and it still seems to be the same climb time, i.e. 7 min 45 s.

This can be compared to the IRL data of 9.19 min for 2.02 ata (See 7th row in first table below):

 

 

This is also in good agreement with an alternative method estimate of 9.2 min based on eyeballing the average climb time from the attached chart which AFAIK is for Sondernotleistung 2.02 ata.

 

Both these figures indicate that the DCS Dora climb rate at 1.8 ata is higher than the IRL data for 2.02 ata.

 

So based on the above, I think it is proven that the Dora climb rate in DCS at 1.8 ata is currently way to high in comparison to historical data and it therefore seems appropriate to move this thread to the bug section.

 

Real measurements are little bit different and look different from the calculated estimation of Flugmechanic. For example, this one is for Kampfleistung and 4070 kg. I think you can recalculate it for 4270 kg. By the way, the experimental points better represent real knees of the curve than the spline.

http://www.wwiiaircraftperformance.org/fw190/Fw_190_V53_climb.jpg

 

http://www.wwiiaircraftperformance.org/fw190/Fw_190_D-9_210001_FB3_climb.jpg

 

or

 

http://www.wwiiaircraftperformance.org/fw190/Fw_190_D-9_210002_FB_Nr1.pdf 4300 kg 3000 rpm

 

As far as I can see, measured Vy for the same power and weight is 10% higher than estimated... so the times can be differer much more because of low slope of the time curve an 9000 m.

Edited March 7, 2015 by Yo-Yo