Mikoyan-Gurevich MiG-15bis

[Nabutso 13,131]

[JEI2 5,763]

Great.

[Rohnlex 2,367]

Thanks. Keep them coming.

[diversant8 14]

Height, m       Vy, m/s        Time, min       SPD, km/h
0                        50.0                 0                     710
1000                  46.5                0.38                 710
2000                  44.1                0.7                   710
3000                  41.5                1.1                   710
4000                  38.2                1.5                   710
5000                  35.2                1.95                 710

6000                  32.4                2.5                   710
7000                  29.5                2.98                 710
8000                  26.6                3.55                 710
9000                  23.7                4.0                   710
10000                20.8                4.9                   710

 

This is a data from RU forum. Why do the speeds differ?

[Nabutso 13,131]

 

Height, m       Vy, m/s        Time, min       SPD, km/h
0                        50.0                 0                     710
1000                  46.5                0.38                 710
2000                  44.1                0.7                   710
3000                  41.5                1.1                   710
4000                  38.2                1.5                   710
5000                  35.2                1.95                 710

6000                  32.4                2.5                   710
7000                  29.5                2.98                 710
8000                  26.6                3.55                 710
9000                  23.7                4.0                   710
10000                20.8                4.9                   710

 

This is a data from RU forum. Why do the speeds differ?

 

Typo on my part. I accidentally used the speeds for the MiG-15 climb, sorry.

[MessereMesser 910]

will it have the automatic brakes that deploy when nearing mach1? 

[Nabutso 13,131]

will it have the automatic brakes that deploy when nearing mach1? 

According to the FM team, it had no automatic breaks. There is nothing in the technical description of the MiG-15Bis that says anything about the air breaks opening automatically, you're welcome to take a look through it.

[MessereMesser 910]

According to the FM team, it had no automatic breaks. There is nothing in the technical description of the MiG-15Bis that says anything about the air breaks opening automatically, you're welcome to take a look through it.

http://books.google.co.uk/books?id=CPXN5nm31o0C&pg=PA78&lpg=PA78&dq=mig+15+automatic+air+brakes&source=bl&ots=xJiu7AjT5H&sig=Mk2L_xWcsc4ZdZe4VXB3CYO1SLQ&hl=en&sa=X&ei=7AiEVO3SD8SzUfK5gfAI&redir_esc=y#v=onepage&q=mig%2015%20automatic%20air%20brakes&f=false

According to this book, it deployed near the red line limit. This is from tests on a defected NK mig by the Americans. 

[Nabutso 13,131]

http://books.google.co.uk/books?id=CPXN5nm31o0C&pg=PA78&lpg=PA78&dq=mig+15+automatic+air+brakes&source=bl&ots=xJiu7AjT5H&sig=Mk2L_xWcsc4ZdZe4VXB3CYO1SLQ&hl=en&sa=X&ei=7AiEVO3SD8SzUfK5gfAI&redir_esc=y#v=onepage&q=mig%2015%20automatic%20air%20brakes&f=false

According to this book, it deployed near the red line limit. This is from tests on a defected NK mig by the Americans. 

Yeah I know there are sources out there that say that, but there is nothing mentioned about it anywhere in actual documentation about the plane.

[SubRyan 5,556]

Is the takeoff weight MAUW? What context is that takeoff weight given for? Combat load?

Edited December 7, 2014 by SubRyan

[Nabutso 13,131]

Best climb speed?

 

710 TAS at all altitudes below 13000 m, or follow the IAS listed below.

[Nabutso 13,131]

Is the takeoff weight MAUW? What context is that takeoff weight given for? Combat load?

The take-off weight of 4960 kg corresponds to full internal fuel without fuel tanks.

 

[SubRyan 5,556]

The take-off weight of 4960 kg corresponds to full internal fuel without fuel tanks.

 

So my next question is, with full internal fuel tanks what was the max endurance on the MiG-15bis?

[Nabutso 13,131]

So my next question is, with full internal fuel tanks what was the max endurance on the MiG-15bis?

2h, 6 min.

[SubRyan 5,556]

2h, 6 min.

 

If that is the case, then why is the max fuel for the bis in game for a 29 min endurance? That is 23% of the maximum possible endurance.

 

Isn't the minimum fuel load for planes in game supposed to equal ~30% maximum endurance?

[Nabutso 13,131]

 

If that is the case, then why is the max fuel for the bis in game for a 29 min endurance? That is 23% of the maximum possible endurance.

The max fuel ingame is at 100% throttle. Endurance is not fuel time at 100% throttle.

 

 

Isn't the minimum fuel load for planes in game supposed to equal ~30% maximum endurance?

Nah. Fuel loads in game range from ~30% minimum, 30 min, 45 min, 1 hour etc in intervals (in fuel amount at 100% throttle at SL, literally the amount of gallons/liters in the tanks total/fuel consumption at SL, 100% throttle). This can be extended by flying at different settings, altitudes etc. That is how, for example, you can achieve the real world 'endurance' of the Me163 of ~12 min (100% throttle fuel time should actually be 4 min 11 seconds for the 163).

[SubRyan 5,556]

The max fuel ingame is at 100% throttle. Endurance is not fuel time at 100% throttle.

 

Nah. Fuel loads in game range from ~30% minimum, 30 min, 45 min, 1 hour etc in intervals (in fuel amount at 100% throttle at SL, literally the amount of gallons/liters in the tanks total/fuel consumption at SL, 100% throttle). This can be extended by flying at different settings, altitudes etc. That is how, for example, you can achieve the real world 'endurance' of the Me163 of ~12 min (100% throttle fuel time should actually be 4 min 11 seconds for the 163).

 

How much internal fuel was carried, by weight? I want to check that and calculate the range at SL using a specific fuel consumption of the VK-1 of 2.97 x 10^-5 (kg*sec^-1) / N, and the max VK-1 static thrust of 26476 N

Edited December 9, 2014 by SubRyan

[Nabutso 13,131]

How much internal fuel was carried, by weight? I want to check that and calculate the range at SL using a specific fuel consumption of the VK-1 of 2.97 (kg*sec^-1) / N, and the max static thrust of 26476 N

~1160 kg.

[SubRyan 5,556]

~1160 kg.

 

Hmmm

 

I get a time of 24 min 35 seconds

 

Close enough

[Nabutso 13,131]

Hmmm

 

I get a time of 24 min 35 seconds

 

Close enough

May come from the fact that, in flight, the engine does not produce that static thrust value, it's a bit lower. 

[SubRyan 5,556]

May come from the fact that, in flight, the engine does not produce that static thrust value, it's a bit lower. 

 

Does the manual state the thrust output for 100% at sea level?

[Nabutso 13,131]

Does the manual state the thrust output for 100% at sea level?

 

X: speed, km/h, in.. TAS I think.

Y: kgf

 

Channel losses:

 

 

Though I think fuel consumption would be before the channel losses.

 

There is also this:

 

 

4th column is "Fuel consumption when not moving, in kg/h"

 

With 1160 kg of fuel, and not moving, the MiG-15Bis should last about ~0.4 hours (or 24 minutes, like you calculated).

[SubRyan 5,556]

 

X: speed, km/h, in.. TAS I think.

Y: kgf

 

Channel losses:

 

 

Though I think fuel consumption would be before the channel losses.

 

There is also this:

 

 

4th column is "Fuel consumption when not moving, in kg/h"

 

With 1160 kg of fuel, and not moving, the MiG-15Bis should last about ~0.4 hours (or 24 minutes, like you calculated).

 

What is the n = 11560 say in the first graph? It is some unit over minute

 

It makes sense that fuel consumption is calculated for total thrust, as channel losses are still energy that was produced

 

So does the MiG-15bis have too much fuel at the moment? Or is the fuel consumption in game off?

Edited December 9, 2014 by SubRyan

[Nabutso 13,131]

11560 is the max RPM. The 100% setting ingame.

 

11200 RPM is the next step down.

 

Well, you did the calculations for thrust at SL when the aircraft is just sitting on the runway. Since the thrust changes depending on the speed, the fuel consumption seems based on a value that places it at some point in flight. Just do the calculation backwards and find how much thrust it's producing for 29 minutes.

[SubRyan 5,556]

11560 is the max RPM. The 100% setting ingame.

 

11200 RPM is the next step down.

 

Well, you did the calculations for thrust at SL when the aircraft is just sitting on the runway. Since the thrust changes depending on the speed, the fuel consumption seems based on a value that places it at some point in flight. Just do the calculation backwards and find how much thrust it's producing for 29 minutes.

 

Hmmm

 

• MiG-15bis starts out with 28 min 31 seconds of fuel.
• Since aircraft weight isn't reported in the API (it should be), I'm assuming 1160 kgs of fuel for a max tank w/o drop tanks
• In-game thrust (after losses) was 2267 kgf using the API for maximum speed at 10m (1075 km/hr)
• Accounting for a 9.5% channel loss, thrust produced was 2504 kgf (24555 N) 

Even with all that, I still get a specific fuel consumption of 6.01 x 10^-5 kg*sec^-1/N

 

Calculating for time using a SFC of 2.97 x 10^-5 and the max thrust before losses (24.6 kN), I get a time of 26 min 31 seconds

 

Something doesn't seem right.

Edited December 9, 2014 by SubRyan