I’d like to point out a realism issue I’ve observed across several aircraft in the simulator. Regardless of weight configuration, aircraft tend to lift off the runway too rapidly after rotation. Even with large, heavy jets such as the A380, the aircraft becomes airborne almost instantly, whereas in real-world operations, there is typically a short delay of a few seconds before the main gear leaves the ground.
Adjusting this behavior to better reflect real-world physics would enhance realism during the takeoff phase and improve the overall experience for users who value accurate flight dynamics.
Thank you for your time and for continually improving Infinite Flight.
It’s mostly caused by going way too fast for the takeoff roll. 180-210 knots. To get a realistic takeoff you need to rotate way sooner. 110-150 knots for the delay you’re speaking of.
@Derrick778 I can tell you right now, you were waaayyy too late on your rotation. Most aircraft, like was said above, rotate far before reaching 170kts
You are still on the ground and going almost 180kts. I rotate at 150kts with a fully loaded C-17. At this speed any aircraft is going to “jump” off the runway, whether in IF or in real life. Try rotating at the correct Vr and I promise you you’ll see the difference. It’ll feel much more realistic
To be clear: the screenshot above is from the moment of rotation for your replay
I fly the 747-200 a lot and I rotate at 150 to 170 knots and at those speeds I get the delay he’s speaking of. Nose goes up and a second or two later the rest of the plane follows. Rotating at 180-190 knots will cause you jump up (like you said) cause of how much lift you’ve already generated from those speeds. You could (possibly) take off without flaps at those speeds
So the T to W ratio is 0.29 approx at mtow which the aircraft can rotate at about 145 knots to play it safe and allow the plane to gain more momentum and pitch up to 15⁰… dont over rotate and away you go.
I can get the 777 at 35000 under 20 minutes which is realistic… these aircraft preform well better than what you think
Do you know what the actual temp was when you took off?
From the temp info further below it looks likely you put in too high a temperature into the model, giving you an excessive take-off speed goal. (edit: there is the fix to this in a later message)
And that would definitely make you leave the runway more rapidly (for temperatures more normal for this time of year at that location)
I haven’t looked at the video but 88.6% N1 may be too high for a thrust rating at D-TO2 with a flex of 42°C which may cause you to have excess power leading to the “jump” effect. I can’t be sure because IF can’t accurately simulate the appropriate flex thrust settings so that’s the only thing I could think of if those are the numbers SimBrief is providing.
Given that performance data, I’d probably try 82.4% ish for the B772/B77F or about 84.8% for the B77W. These are rough estimates but it’s what I use if presented with that thrust setting. You can derive some yourself based on watching YouTube videos of 777 takeoffs and pay attention to their thrust settings. D-TO is full rated thrust which can have a flex which will reduce the thrust setting. D-TO1 is derated 5% from full rated thrust that can also have a flex setting (D-TO2 is 10% derated)
Assumed temperature has nothing to do with the outside air temperature, it is just a way of calculating the correct derated thrust setting for takeoff.
Ground roll is longer (GS is higher), but IAS is pressure speed. So by reference to IAS the pressure speed (lift generation dynamic pressure) is taken care of.
So, the question still remains why the relatively high IAS was specified?
I haven’t watched the replay, so I can’t be sure what the issue actually is, but Josh said that your N1 was 88.6%. For the aircraft weight (around 272T), I use an N1 of 86.5%-87% when around sea level. Taking off with an N1 setting even 2% higher can make the aircraft pitch upwards faster and can lead to a slightly quicker than usual lift-off. That’s tough to calculate in Infinite Flight, so I guess you just have to familiarise yourself with the aircraft.
A little thing I now keep in mind when rotating in-game is the target rate of rotation. Irl, aircraft usually pitch up at a rate of 2-4° per second (obviously starting slower when beginning the rotation). I aim for 3° per second, which usually gets me off the ground 3 or 4 seconds after initial pitch up - similar to irl performance.
My conclusion is that a combination of slightly higher-than-ideal thrust along with maybe a higher than usual rate of pitch increase contributed to a quick lift-off. As I said earlier, I didn’t watch the replay so I might be wrong here, but I’m also speaking off my past experience where I also had troubles with the same issue.
