non-afterburner takeoff

I seem to not be able to get the bird in the air without using the afterburner... In the training mission that came with MIG-21BIS I run out of runway length when taking off at full military power at 5 degrees nose up on KPP

and on instant action mission, I have my tires blow up on me when taking off without AB on and just using full military power.

Strange behavior on take-off

Have you exceeded the payload weight?

I don't think so, I have a clean aircraft with only 100% fuel... No payload at all

total weight is 8621 KG

trying takeoff from mineral vody since it has longest runway in map and my Mig's tire goes flat at 358 km/hr

I've just tried, with 103% of max takeoff weight :D, no AB, from Batumi. I took of without problems, but it took me like 2 minutes to climb above 100m.:D

Can you post a video showing your controls indicator? Tracks are buggy unfortunately.

trying takeoff from mineral vody since it has longest runway in map and my Mig's tire goes flat at 358 km/hr

At 358km/h it should fly, afterburner or not. My advice is to give the stick a slightly firmer pull shortly after 300km/h to get off the ground, then level out a little again as you'll climb very slowly.

i'll try to post a video

The 42A tires are rated to 370 km/h. I think blowouts happen with FT takeoffs because the tire doesn't cleanly leave the pavement and there are a lot of rapid cycles of touching/not-touching that runs up a wear counter or something.

By the book FT takeoff is permissible with "no external loads or two missiles" when takeoff run length is not longer than 1,100m. Under standard conditions (760mm Hg, 15°C, no h/w) this corresponds to a GW of ~9350 kg. So even clean we shouldn't be doing FT takeoffs at 9800 kg unless we are low pressure, cold, or with a headwind.

Book also says to adopt 11-13° by the UUA-1 but with the delicate tires, FM, and so on I'd say pull 15 for FT takeoffs.

Interesting. I tried non-afterburner takeoffs in several configurations at full fuel and it always managed to get off the runway. Though as Grunf said, climbing is a bit leisurely till airspeed increases.

Are you using take-off flaps? Taking off with a clean wing certainly requires a higher rotation speed and eats up runway. You also need more AOA for lift-off without flaps, though I managed to do it at Kobuleti without too much struggle. All of these take-offs were at 100% fuel and clean.

-Nick

I do this often with 800l fuel tank and 4 missiles... full flap, full brake until max dry thrust!

Interesting. I tried non-afterburner takeoffs in several configurations at full fuel and it always managed to get off the runway. Though as Grunf said, climbing is a bit leisurely till airspeed increases.

 

Are you using take-off flaps? Taking off with a clean wing certainly requires a higher rotation speed and eats up runway. You also need more AOA for lift-off without flaps, though I managed to do it at Kobuleti without too much struggle. All of these take-offs were at 100% fuel and clean.

 

-Nick

Of course. Try to keep your UUA-1 to less than 13° and let me know how it goes.

Of course. Try to keep your UUA-1 to less than 13° and let me know how it goes.

It goes fine...but I'm not the one having trouble with take-offs. ;)

-Nick

she dances on those main gear as I try to get her up in the air... Its like she is trying to fall apart on purpose.

I had some better luck after some practice but still the main gear tires are blowing up on me

I keep blowing tyres on this bloody thing, seems if I dont give aft stick at 250Kph and try and pull this thing firmly in the air I blow tyres as I hit 300Kph.

she dances on those main gear as I try to get her up in the air... Its like she is trying to fall apart on purpose.

 

I had some better luck after some practice but still the main gear tires are blowing up on me

I keep blowing tyres on this bloody thing, seems if I dont give aft stick at 250Kph and try and pull this thing firmly in the air I blow tyres as I hit 300Kph.

Did you both remember to disengage the parking brake, or are you trying to take off with it engaged ?

Did you both remember to disengage the parking brake, or are you trying to take off with it engaged ?

The parking brake!?

Edit - do you mean the nose gear brake lever? Its nothing to do with that as its always one of the rear tyres that goes

what parking brake???

I get it too. I think it has something to do with the extended period of near zero vertical velocity associated with such a takeoff. I'd have to double check but I think a rotation speed much higher that produced a decisive and positive unsticking from the runway would sidestep the issue.

Given a very long runway (like Groom lake) its possible to balance the aircraft at a liftoff speed and takeoff attitude well below the tire rating speed in grazing contact with the runway and the tire surely fails.

EDIT: There is an emergency brake knob (red, upper left portion of dash) that can be used as a parking brake of sorts. It's unlikely you used it repeatedly without very deliberate application.

Is this the right way to take-off? BTW this is with afterburner

Note: You can hear my voice in the background whinging about my blown tires on takeoff lol... I was the number 2 in the flight and was on left side of leader... The perspective seen in the video is from the view of the flight leader NaCH

It looks good, but doesn't solve the mystery of your overly brittle tyres. Just as he does in the video, go straight until you pass 300 to 320 km/h, then rotate and fly out. It's a little more than 5° up, but no surprises.

To go in a different direction: what kind of controls are your brakes mapped to? If you have them on an axis and that's not properly calibrated, you might have some break pressure heating up your tyres.

my brakes are the spacebar key, which I don't use for take-off

Flight manual says 3/4th back stick at 270km/h for takeoff. Can't remember what AoA you're supposed to hold though.

I can't help but wonder if the military power thrust is too low.

The parking brake!?

 

Edit - do you mean the nose gear brake lever? Its nothing to do with that as its always one of the rear tyres that goes

what parking brake???

 

EDIT: There is an emergency brake knob (red, upper left portion of dash) that can be used as a parking brake of sorts. It's unlikely you used it repeatedly without very deliberate application.

This one (in bold), if that knob/lever is extended from the instrument panel towards the pilot, than you have the "parking brake" engaged...

Pay attention that, as the knob/lever moves in longitude, it may be misleading to understand if it's engaged or not.

Try pressing it several times, and make sure it is collected all the way to the instrument panel.

Or better, just don't touch it at all. It was never designed or meant to be used as a parking brake in the first place.

Yeah can't say i have ever engaged that to be honest so its not a concern for me.

I think the mig might be suffering with too much drag, and this is part of that wider problem.

I never ever touched that too, just the nose wheel lock once lined up on runway (big grey handle)