Dora Boost and Speed

[USARStarkey]

So how finished is the Dora exactly? What boost is this thing supposed to have according to ED? I was under the impression it was supposed to be B4 + MW50 at 1.8 ata. So why is it that you can get 1.93ata? I've seen this several times now around 14-16k. It also seems as though the Dora can clock in at 430+mph in level flight all the way from 13k to 26k, and thats just the altitudes I've tested. It is very hard to test level flight in the Dora, because of the poor trimming ability. If someone else out there has a steadier hand, have at it.

 

Next is the climb rate. I was able to achieve over 5500 ft per minute. At one point, I hit 5800. The Dora had a historical rate of climb of about 4300fpm. This thing is doing nearly 6000. This was at FULL fuel, starting at 135 knots 150ft off the ground and ACCELERATING into the climb.

 

https://www.youtube.com/watch?v=N59oFcjEpLU&feature=youtube_gdata

dora 1.9.trk

Edited August 26, 2014 by USARStarkey

[Altflieger]

B4 + MW50 at 1.8 ata? Still having nightmares about the K4?

[USARStarkey]

hardly

[ClearDark]

So how finished is the Dora exactly? What boost is this thing supposed to have according to ED? I was under the impression it was supposed to be B4 + MW50 at 1.8 ata. So why is it that you can get 1.93ata? I've seen this several times now around 14-16k. It also seems as though the Dora can clock in at 430+mph in level flight all the way from 13k to 26k, and thats just the altitudes I've tested. It is very hard to test level flight in the Dora, because of the poor trimming ability. If someone else out there has a steadier hand, have at it.

 

Next is the climb rate. I was able to achieve over 5500 ft per minute. At one point, I hit 5800. The Dora had a historical rate of climb of about 4300fpm. This thing is doing nearly 6000. This was at FULL fuel, starting at 135 knots 150ft off the ground and ACCELERATING into the climb.

 

https://www.youtube.com/watch?v=N59oFcjEpLU&feature=youtube_gdata

 

A quick glance at your 'Recent Posts' page shows you do nothing but complain on these forums.

 

Next......

[Narushima]

Guys, play the ball, not the man.

[Yo-Yo]

So how finished is the Dora exactly? What boost is this thing supposed to have according to ED? I was under the impression it was supposed to be B4 + MW50 at 1.8 ata. So why is it that you can get 1.93ata? I've seen this several times now around 14-16k. It also seems as though the Dora can clock in at 430+mph in level flight all the way from 13k to 26k, and thats just the altitudes I've tested. It is very hard to test level flight in the Dora, because of the poor trimming ability. If someone else out there has a steadier hand, have at it.

 

Next is the climb rate. I was able to achieve over 5500 ft per minute. At one point, I hit 5800. The Dora had a historical rate of climb of about 4300fpm. This thing is doing nearly 6000. This was at FULL fuel, starting at 135 knots 150ft off the ground and ACCELERATING into the climb.

 

https://www.youtube.com/watch?v=N59oFcjEpLU&feature=youtube_gdata

 

 

MP is nothing in terms of Jumo-213 automatics because it does not maintain constant MP but constant filling or air mass flow that is the distinctive feature. That's why MP depends on the actual temperature at the certain altitude, for example. In standard atmosphere as you climb and especially after blower gear shift MP increases. Factory manuals never gave MP as a reference for the certain power ratings, only rpm and fuel consumption.

[NeilWillis]

I was able to achieve over 5500 ft per minute. At one point, I hit 5800. The Dora had a historical rate of climb of about 4300fpm. This thing is doing nearly 6000. This was at FULL fuel, starting at 135 knots 150ft off the ground and ACCELERATING into the climb.

 

https://www.youtube.com/watch?v=N59oFcjEpLU&feature=youtube_gdata

 

Climb rates will be higher at low level, and drop off significantly at altitudes closer to it's service ceiling. What did it fall to there, and did you calculate the climb rate over the whole climb profile, or are you just picking spurious data from the air, and trying to pull apart the sim?

 

Frankly, there are lies, damned lies and statistics according to a well known quote. Without some context, the numbers in your posting are about as much use as a chocolate supercharger!

 

If you want to pull things apart, please be a little more scientific, and less critical without hard evidence to back up your claims.

[USARStarkey]

Climb rates will be higher at low level, and drop off significantly at altitudes closer to it's service ceiling. What did it fall to there, and did you calculate the climb rate over the whole climb profile, or are you just picking spurious data from the air, and trying to pull apart the sim?

 

Frankly, there are lies, damned lies and statistics according to a well known quote. Without some context, the numbers in your posting are about as much use as a chocolate supercharger!

 

If you want to pull things apart, please be a little more scientific, and less critical without hard evidence to back up your claims.

 

My OP was phrased somewhat as a question for a reason. Do your own tests and see what you get.

[NeilWillis]

I'll wait for the full release before i even start to think about how close to prototype it might be. I apologise if I waded in there thinking it was the start of another "Prop wash" thread.

[Pilum]

So how finished is the Dora exactly? What boost is this thing supposed to have according to ED? I was under the impression it was supposed to be B4 + MW50 at 1.8 ata. So why is it that you can get 1.93ata? I've seen this several times now around 14-16k. It also seems as though the Dora can clock in at 430+mph in level flight all the way from 13k to 26k, and thats just the altitudes I've tested. It is very hard to test level flight in the Dora, because of the poor trimming ability. If someone else out there has a steadier hand, have at it.

 

Next is the climb rate. I was able to achieve over 5500 ft per minute. At one point, I hit 5800. The Dora had a historical rate of climb of about 4300fpm. This thing is doing nearly 6000. This was at FULL fuel, starting at 135 knots 150ft off the ground and ACCELERATING into the climb.

 

https://www.youtube.com/watch?v=N59oFcjEpLU&feature=youtube_gdata

 

Yes, the climb rates you posted above seem a bit on the high side.

 

This is the climb rates I get out of my C++ simulation from sea level to 3 km altitude:

 

Engine and power setting? Valid choises:

 

3 = Junkers Jumo 213A Start und Notleist mit Mw50

 

3

 

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

 

EDIT: Sorry for the formatting, will post a figure next time.....

 

Concerning speed: I get 686 Km/h or 426 mph 13 k altitude and 688 Km/h at 26 k altitude so not much deviation there......

Edited August 29, 2014 by Pilum
Based on popular demand, I have now changed fps to fpm ;-)

[sobek]

climb (fps)

 

Sure about that?

[Yo-Yo]

Yes, my estimation gives the same results within 2% difference, that's ok.

 

I can not understand though, why your calculation maintains TAS at climb? IAS is almost constant, not TAS.

[USARStarkey]

Upon referencing actual flight tests, 430mph is possible. However, I cant get the 51 to go to its historical speeds. It is much easier to keep the pony level and I cant get past 430mph at at altitude, and Ive tried everything from 20k up to 30k. I would have expected to get about 440-442 somewhere between 24k and 28k but It wont go past 430mph in sustained level flight. The AI on the other hand, can get 440mph at 28,000. I have tried chasing the AI, and I cant keep up.

 

Ok, engine boost thing solved. So what is the explanation for the 1000fpm too high climb?

[Narushima]

Many things. Perhaps Tacview does not take into considuration corrections for centripetal force (without this correction the Dora's climb rate was 24 m/s). Perhaps the radiator flaps were closed (Finns managed to increase climb rate of the bf 109G by 2 m/s simply by climbing at a shallower angle, increasing speed and closing the radiator flaps). Perhaps you were slightly zoom climbing. You were pulling slight G when you were climbing in your video, meaning you were increasing the climb angle.

 

Best way to test climb rate: go from 100m to 1100 with open radiator flaps, record the time, divide by this time (in seconds) and you get average climb rate in m/s. Your starting speed indicated has to be equal to your end speed indicated.

[USARStarkey]

Many things. Perhaps Tacview does not take into considuration corrections for centripetal force (without this correction the Dora's climb rate was 24 m/s). Perhaps the radiator flaps were closed (Finns managed to increase climb rate of the bf 109G by 2 m/s simply by climbing at a shallower angle, increasing speed and closing the radiator flaps). Perhaps you were slightly zoom climbing. You were pulling slight G when you were climbing in your video, meaning you were increasing the climb angle.

 

Best way to test climb rate: go from 100m to 1100 with open radiator flaps, record the time, divide by this time (in seconds) and you get average climb rate in m/s. Your starting speed indicated has to be equal to your end speed indicated.

 

I adjusted climb angle to be higher because the airplane was still accelerating, so not a zoom.

[Yo-Yo]

The best way to determine climb is to use TAS and VS together. I do not understand - using flight recorder this way is something like nailing with a microscope.

 

TacView allows to record flight parameters, so, use TAS and VS (or altitude, it's the same) to come to the formula

 

VS_full = VS + n_x * TAS, where n_x = (dTAS/dt)/g

 

Applying this math to the climb history recording where the altitude is specified you can select then 3-5 time points with the centrum at the certain altitude to build a chart or to use the record directly (too many points though!) to plot a chart - climb rate vs altitude and altitude vs time.

[Pilum]

Yes, my estimation gives the same results within 2% difference, that's ok.

 

I can not understand though, why your calculation maintains TAS at climb? IAS is almost constant, not TAS.

 

I don't maintain TAS: Maybe it was confusing to post the first column after altitude which is TAS. The way I have it set up is I define a sea level speed for the climb and then this speed will be maintained as IAS (third column) with a reduction of the IAS used in the climb to get the best climb rate at any given altitude. This is what I get in the simulation and also what seems to be the case IRL because all pilot's notes I've seen all indicate a lowered IAS to be maintained for best climb as altitude goes up.

[xentxo]

1st row:

To my knowledge 22.65 m/s climb = 74.31 fps climb

So what does "4470.28 fps" mean?

 

Edit:

question is now overcome

Means ft per minute = fpm

Edited August 29, 2014 by xentxo

[Spuds]

Same here!

 

I have been in a vertical fight and noticed FW accelerates out of a 160 mph in a climb leaving the mustang in a stall, 10 minutes of AI going vertical every time. Gives him the advantage, tried everything, lead the aircraft, flew defensive turns, even tried running from them full power, they just have every advantage. My skills are limited however, the damage model and performance seems out of tune?