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Speed at rotation


outbaxx
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I've tried to do some short take offs but there are some things that I can't get my head around.

No matter what the aircraft weight, I can't start rotate before 250kmph.

 

According to the charts the minimum recommended speed of rotation is between about 150-220 kmph depending on weight.

The recommended would imply that it could be done earlier but it's not recommended, right?

But I can't do it on a clean aircraft at 50% fuel, not even at 20% fuel. The nose will not raise until the speed reach about 250 kmph.

 

Am I doing this wrong?


Edited by outbaxx
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I don't recall charts. According to the manual, ADI based take off procedure states 250 and 280 km/h IAS:

- At 280 km/H to a 10° climb attitude when using maximum power without afterburner

- At 250 km/H to a 13° climb attitude when using afterburner

 

Just roughly, based on the observations, when using HUD method the take off speed is ~270 km/h - but I guess it depends on the TO weight.

F/A-18, F-16, F-14, M-2000C, A-10C, AV-8B, AJS-37 Viggen, F-5E-3, F-86F, MiG-21bis, MiG-15bis, L-39 Albatros, C-101 Aviojet, P-51D, Spitfire LF Mk. IX, Bf 109 4-K, UH-1H, Mi-8, Ka-50, NTTR, Normandy, Persian Gulf... and not enough time to fully enjoy it all

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I'm reading the SFI part 2 and with a weight of 19 tons and +30C the minimum recommended rotation speed in the SI is about 235 kmph.

My problem is that you can't rotate the aircraft at that speed even if you weigh 13 tons. This is with zone 3.

The chart say that with MS and a weight of 17 tons and +30 the SI rotation speed is about 305 kmph. The chart don't even show higher than 17 tons for MS so perhaps there is a restriction there?

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The chart say that with MS and a weight of 17 tons and +30 the SI rotation speed is about 305 kmph. The chart don't even show higher than 17 tons for MS so perhaps there is a restriction there?

 

I could easily imagine so, yes. On a hot day with a heavy plane you want EBK.

 

The aerodynamics compendium talks a lot about the dangers of circumstances like that. If you over-rotate you might end up not being able to sustain level flight.

Win10 x64 | SSDs | i5 2500K @ 4.4 GHz | 16 GB RAM | GTX 970 | TM Warthog HOTAS | Saitek pedals | TIR5

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I rotate at 280-300. I make sure that at 300 I am on the last rubber on the rear wheels. Right now there does not seem to be a different sound when airborne. I have a ButtKicker and when in stages 2 and 3 there is no wheel sound when leaving the ground. I know it will be resolved. In the Mig-21, as soon as I leave the ground I feel it with the ButtKicker and I also feel the thumps when the gear locks into the wheel wells. Scared the $h1t out of me when I first flew with the ButtKicker. In closing I don't think it is a matter of rotating at a lower speed but how fast the Viggen can get up to 280. I lock the brakes through stage 1 and once she rolls a tad, release brakes, ramp up through stage 3 and she takes off like a dragster.

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Speed at rotation

 

I could easily imagine so, yes. On a hot day with a heavy plane you want EBK.

 

 

 

The aerodynamics compendium talks a lot about the dangers of circumstances like that. If you over-rotate you might end up not being able to sustain level flight.

 

 

 

The thing is that I can't even lift the nose until 230 something. So it's not possible to rotate too early for me. And if I force lift it at that speed with full aft stick, I'm at alpha 20 as soon as there is some lift(because I'm full stick aft and over rotating)

 

If should be able to rotate or at least start to rotate at 165 kmph given my weight according to the charts.

I'm at 50% fuel =2000kg of fuel

Ac + driver is 10749kg

So my TO weight is 12749kg


Edited by outbaxx
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The thing is that I can't even lift the nose until 230 something. So it's not possible to rotate too early for me. And if I force lift it at that speed with full aft stick, I'm at alpha 20 as soon as there is some lift(because I'm full stick aft and over rotating)

 

Well first of all I agree that there seems to be a problem here. If the manual recommends a rotation speed that's not achievable in-game that's obviously a problem. I was just saying that in that specific scenario there probably IS a limit on how heavy you can be for an MS takeoff being safe.

 

Maybe this needs a bug thread? "Manual says I should be able to rotate at v = V with w = W, but I can't." Seems like a pretty obvious bug to me.

Win10 x64 | SSDs | i5 2500K @ 4.4 GHz | 16 GB RAM | GTX 970 | TM Warthog HOTAS | Saitek pedals | TIR5

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Speed at rotation

 

Well first of all I agree that there seems to be a problem here. If the manual recommends a rotation speed that's not achievable in-game that's obviously a problem. I was just saying that in that specific scenario there probably IS a limit on how heavy you can be for an MS takeoff being safe.

 

Maybe this needs a bug thread? "Manual says I should be able to rotate at v = V with w = W, but I can't." Seems like a pretty obvious bug to me.

 

 

 

Well, to be honest, I don't know what the manual says. I'm looking at the charts in SFI AJS37 part 2 chapt IV page 11.

 

And I see I misread the recommended airspeed, it says that the SI show the recommended airspeed as 250kmph. And it also say that the minimum allowed speed of rotation is 190 kmph.

But the chart show that it can be done at lower speeds.


Edited by outbaxx
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