Challenge: Climb 20 km in 7 minutes

MiG-21_climb_20km_mach2.zip

That looks fun to do !

What is the pitch for climbing from 10km to 20km ? Thanks :)

That looks fun to do !

What is the pitch for climbing from 10km to 20km ? Thanks :)

Acceleration to Mach 2 while climbing, time to be at 20 kilometres 7 minutes.

No info for pitch angle, but with constant rate you should be 23 metres per second.

Just did it in 6 minutes and 38 seconds. Temperature was set to 15 celsius. Did my own custom profile though as it is more effective. 60 deg climb is waaay too steep for the 21 and it is better to accelerate lower (around 7000m) and in a shallow descent up to Mach 1.4. Subsonic below 10000m is a peacetime regulation so that you don't brake too many windows :)

MiG-21 7minute climb.trk

Brake release was at 08:00:30

Just did it in 6 minutes and 38 seconds. Temperature was set to 15 celsius. Did my own custom profile though as it is more effective. 60 deg climb is waaay too steep for the 21 and it is better to accelerate lower (around 7000m) and in a shallow descent up to Mach 1.4. Subsonic below 10000m is a peacetime regulation so that you don't brake too many windows :)

Those were the real Mig-21 parameters for the 20 km altitude climb.

You will keep accelerating in 60 degree climb up to 10 km altitude.

Those were the real Mig-21 parameters for the 20 km altitude climb.

You will keep accelerating in 60 degree climb up to 10 km altitude.

MiG-29 maybe lol....

You might have misunderstood something, but it's not important anyway. There is the track, and 6:38 is the new time to beat :) (keep it at 15 celsius) (timer stopped when cockpit altimeter read 20000m)

Nice challenge

1st attempt: engine flameout at 12,000m

2nd attempt: first movement visible with Tacview at 08:00:10 // in the air at 08:00:26 // some not so optimal flying skills and another profile // 20.069m at 08:06:31 near the border to ossetia near Sachere / well 800 Liters left -> landing in Nalchik with 350 liters left,

08:00:10 - 08: 06: 31 = 06: 21

I'll try the original profile in the next few days

Is sustained level flight required at the top? Because I just did 103,000 feet in 6 min 45 sec. ;)

It was rather ballistic though

Well, Mach2 at 20000m was the task, I guess you passed that at some point if you climbed to 100k feet. You'll need to provide a track though.

Nice challenge

1st attempt: engine flameout at 12,000m

2nd attempt: first movement visible with Tacview at 08:00:10 // in the air at 08:00:26 // some not so optimal flying skills and another profile // 20.069m at 08:06:31 near the border to ossetia near Sachere / well 800 Liters left -> landing in Nalchik with 350 liters left,

08:00:10 - 08: 06: 31 = 06: 21

 

I'll try the original profile in the next few days

Post track or tacview please!

MiG-29 maybe lol....

You might have misunderstood something, but it's not important anyway.

I am sure it is said to be exactly 60 degree climb at Mach 1 up to 10 km.

Is sustained level flight required at the top? Because I just did 103,000 feet in 6 min 45 sec. ;)

It was rather ballistic though

Interesting how to get there as you should have enough fuel left only for about a minute, as Bis drinks 300 liters per minute and 500 L warning light should lit up as you reach 20 km.

So if you get to 30 km with 300 liters (one minute), then you can set engines to idle and you consume like 80 liters per hour, so you have 200 liters left and you can glide down with the glide ratio of about 5:1, so from 30 km altitude it means you get to glide 150 kilometers engines at idle and maintaining 500 km/h glide speed.

I am sure it is said to be exactly 60 degree climb at Mach 1 up to 10 km.

It is said? Where did you read that? Why don't you start up your DCS, hop into a MiG-21 and see it for yourself?

What happens in DCS is that you reach Mach 1 in even less than 60 seconds, then you can pitch up to 60 and the plane will hold it's speed decently up to 4000 meters, where the emergency afterburner cuts out, and then if you still force the 60 degrees pitch, then you loose all your speed before reaching 10000m

21bis thrust without emergency afterburner is 69KN at sea level, then at like 6000 m it will be only around 60% of that (41KN) while the plane is around 8000kg in that scenario.

So your thrust to weight ratio will reduce to 0,5 by the time you pass even 6000m and it will decrease further as you go higher. (Didn't account for the effect of airspeed and thrust loss is just data for generic jet engine, so obviously these are just ballpark figures)

Do you understand now, why the 60 degrees climb all the way is nonsense?

Even a clean F-16 starts to loose speed over 6000m in that climb

6:39 after a few tries with a wonky profile.

Tacview-20200701-174815-DCS-Time2Climb.zip.acmi.zip

Good try, but you didn't meet the Mach 2 criteria. My time still stands. :)

I looked at the triggers and there are errors in translating Mach to meters per second.

Mach is the worst speed to climb at as the drag is much higher than either slightly slower or faster. By the pilot's instruction manual the initial climb should be made at 950-975 km/h (faster figure without external tank) to 10km and then level acceleration to M1.8 and then climb continues. This is a subsonic climb and then a quick dash to a higher Ps regime.

Wasp raises an interesting notion that I hadn't considered that the 10-11km sonic transition might not be the optimum performance but an abatement regulation. I notice that the sonic speed isn't attained very quickly. Instead I have been overshooting to 11km and using a dive to 10km to try to push through Mach a little faster than level. I will try lower transition altitudes in the future. I guess the limit is not exceeding 1200km/h IAS before you get away from the Mach region. The Ps curves would be most helpful to really get the optimum trajectory. I found a Ps curve that suggests that M1.8 is optimum supersonic and M.9 subsonic.

I don't think the DCS module's TAS needle fully incorporates all the inaccuracies of the real instrument and so displays actual TAS instead of a reduced one. To fly a constant .9 Mach TAS starts about 1125 and reduces to 955 at altitude.

By the book method of getting to M2.0/20km I had lots of fuel left compared to the supplied profile like 1000L although it took a long time especially that final increase to M2 at or approaching 20km. That itself took about 1-2 minutes.

I see the Mach 2 requirement. You mention gliding back, do we need to land also? Or just get to 20k M2?

I see the Mach 2 requirement. You mention gliding back, do we need to land also? Or just get to 20k M2?

Just to get 20 km at Mach 2, but you should have a distance at that point to glide back home just by idling engines.

You can't take a shallow raise that takes you longer distance as reaching 20 km altitude your 500 L warning light lits up and you need to turn engine to idle and get back to base.

So you are not restricted only by the time and speed, but as well by the distance to get up to 20 km altitude and return then engines idling, but returning is just optional.

It is said? Where did you read that? Why don't you start up your DCS, hop into a MiG-21 and see it for yourself?

Please if you understand what he is saying, then correct me as I went it through the translation multiple times:

Challenge was that the youtube translator can't hear clearly what is said, so you can just raise your speakers volume and use like your smartphone to do the audio translation.

But he says that you start to climb to 10 km at angle of 60 degree and then you punch through 10 km at that angle....

He flew in the air force to age 60, over 10 000 hours from that over 1300 hours with the MiG-21's.

There are some other information from other pilots who says same procedure for typical interceptions.

And what I have found, he has only once experienced flame-out situation, otherwise praising the automatic nose cone control for doing what it is suppose to be.

Do you understand now, why the 60 degrees climb all the way is nonsense?

Man who has flown those records says that it is exactly 60 degree all the way up to 10 km and still accelerating.

Yes, he stands in the video next to MiG-21F, but he on another video explains as well next to MiG-21Bis that it has exactly same flight performance and capabilities, regardless that the F flies like a dart where Bis will fly like a bottle as being slightly less stable. Difference being that F consumes 200 L per minute while Bis a 300 L per minute but with increased fuel load and more powerful engine it balances the difference.

So MiG-21Bis in DCS can't do it, then there is something wrong in its modeling.

Please if you understand what he is saying, then correct me as I went it through the translation multiple times:

 

 

Challenge was that the youtube translator can't hear clearly what is said, so you can just raise your speakers volume and use like your smartphone to do the audio translation.

But he says that you start to climb to 10 km at angle of 60 degree and then you punch through 10 km at that angle....

 

He flew in the air force to age 60, over 10 000 hours from that over 1300 hours with the MiG-21's.

There are some other information from other pilots who says same procedure for typical interceptions.

 

And what I have found, he has only once experienced flame-out situation, otherwise praising the automatic nose cone control for doing what it is suppose to be.

 

 

 

Man who has flown those records says that it is exactly 60 degree all the way up to 10 km and still accelerating.

 

Yes, he stands in the video next to MiG-21F, but he on another video explains as well next to MiG-21Bis that it has exactly same flight performance and capabilities, regardless that the F flies like a dart where Bis will fly like a bottle as being slightly less stable. Difference being that F consumes 200 L per minute while Bis a 300 L per minute but with increased fuel load and more powerful engine it balances the difference.

 

So MiG-21Bis in DCS can't do it, then there is something wrong in its modeling.

Ok, first of all, thanks for the video, very interesting, will watch the whole thing when I have the time.

On the other hand it is ridiculous to claim that our DCS MiG-21 is completely wrong based on a single sentence in a foreign language video translated by youtube translator and smartphone translator. Especially since the module performance matches many other things he says.

60 degrees pitch is possible only for the initial climb, if you don't want to loose airspeed.

Ok, first of all, thanks for the video, very interesting, will watch the whole thing when I have the time.

Check as well this English interview:

On the other hand it is ridiculous to claim that our DCS MiG-21 is completely wrong based on a single sentence in a foreign language video translated by youtube translator and smartphone translator. Especially since the module performance matches many other things he says.

The translation works (okay, they are both Google's services) but checked multiple times and each time the same thing.

He explains as well many other things, not just that whole climb up to 10 km with 60 degree angle, but that maximum altitude limit is 21000 for maximum Mach 2.05 speed, as your minimum indicated airspeed is 500 km/h.

60 degrees pitch is possible only for the initial climb, if you don't want to loose airspeed.

He clearly says 60 degree through whole first leg climb to 10 km altitude and still accelerating. Only at the up you roll back to level.

He as well explains that why there are various steps in the full afterburner use because the no:3 fuel tank that is the feeder tank can't keep feeding the engine fast enough so engine will shut down. All the piping from other fuel tanks to feeder tank are too thin to no:3 to keep it full, but the no:3 pipe to engine is big enough keep feeding maximum fuel flow to keep it running.

This is as well again one thing that we don't have in MiG-21Bis, as I can fly all the time with full afterburner and I don't run out of fuel at all, while that should happen after some time. So you need to take your throttle off from after burner for a moment to get all other tanks fill the feeder tank so you can again enable afterburner to keep going.

He btw mentions well that Finland was considering to take Su-22 or MiG-23 in that video, but one thing he doesn't mention is that Finland was in special place that it got as well offered for MiG-25 when Soviet Union took in service. As well MiG-29 was shown to the world first time in 1986 at Finland as Soviet Union wanted Finland to buy it. But as their defense minister decided politically that they buy from the USA, the MiG-21Bis was left as their last Mach 2 aircraft and last from the Soviet Union.

There is one privately owned flight operational MiG-25RBSh in Finland as well (so considering if someone would like to do a MiG-25 module to DCS) (there is some sources saying that it was sold to Latvia or Estonia, but the same man owns MiG-23MLD that he is selling too).

There are as well interesting old open secret documents about the "next fighter" competition that Hornet won, as Soviet Union participated to the competition with MiG-29 offer, but politically Finnish testers were required to raise its price up, so they made MiG-29 costs highest from all. The purchase price, maintenance costs, flight costs, everything was ranked higher than anything else because uncertainty of the Soviet Union future as it had just collapsed so they could do that. In 1990 Soviet Union tried to get Finland participate in developments of MiG-29 for the export markets so that Finland would get the same variant as Soviet Union with possibility to develop improved avionics and weapons to it than even Soviet Union. The candidates were F-16C, F/A-18C, JAS-39 Gripen, Mirage 2000-5. This project was done since 1988 and it was finished in 1992 May.

Prices were:

Aircraft   Purchase Price   Lifetime price (30 years) in -92 inflation.
F-16        8.670 milj.mk    5.500 milj.mk
F/A-18      9.789 milj.mk    6.200 milj.mk
JAS 39     10.653 milj.mk    5.800 milj.mk
M2000-5    10.153 milj.mk    6.700 milj.mk
MiG-29     11.040 milj.mk   10.700 milj.mk (15.years)

There were index set for the delivery period.
M2000-5       Fixed 2.5% per year
JAS 39        Up to 7 % per year up to 1996 and then up to 10 % per year
F-16 F/A-18   Between 3-5% per year
MiG-29        Estimation 3% per year, notice half the lifetime for service (15 years instead 30 years).

I don't know about the inflation or price index changes from 1992 to this date but in 2017 there was such ratio as 1 € = 5.945 mk at 1992.

You know, pilots are human beings, even fighter pilots, and it is possible that what they say is not always 100% accurate.

Look, jet engine's thrust decreases with altitude, as the air gets thinner, there is just less oxygen to work with, so less fuel can be burned so less thrust is available. You'll end up with less than half of the sea level thrust by the time you reach 10km

If you have the DCS F-15 or F-16, take them for a ride and watch the fuel flow indicator as you do a steep climb! Thrust produced is proportional to fuel flow, so you can see it for yourself for better understanding.

Also that might show you, that what you expect here is too much even for a F15 or F16.

For the 21 to be able to climb like you say all the way to 10km, it would need to have at least twice the engine thrust

BTW I hope you know that Dolphin, the dev for the DCS 21 is also an IRL MiG-21bis pilot...

If someone wants to copmpare with this profile:

The fast intercept program for the Bis seems to be like:

Full reheat during all flight

Climb to 10000m at 950km/h TAS

Descend 300m to go supersonic then accelerate to 1200km/h staying 10000m

Climb at 1200km/h IAS until reaching M 1.9

Continue climbing at M 1.9

Final zoom climb would allow to gain some time , allowing IAS down to M 1.5 (?)

Economic cruise return at 11,000m, 510 km/h

BTW I hope you know that Dolphin, the dev for the DCS 21 is also an IRL MiG-21bis pilot...

So first you say that all are just humans, and then you give argument for human, that has radically kept changing the MiG-21Bis flight characteristics and each time telling "It is now correct"?

Sorry, that is illogical.

And yes, I do know that.