Takeoff Time Report - Real Life & IF 2.0

Hi.

It has recently come to my attention that real life takeoff times / length is much longer compared to the length of time that it takes aircraft to takeoff in Infinite Flight. To be absolutely clear, this is not a feature request so please do not request for me to change the topic location. This is a report into whether IF should have an overhaul of timing of takeoff. I will conclude, in the conclusion, if this should happen or not and will take comments into account and can change this decision.

This report will be made of a couple of components, a bit like a school science report:

  • Introduction
  • Data
  • Conclusion

~ Within the introduction will be what the topic will be about
~ The data will include real life data from Airbus and Boeing, including videos from amatuer videographers and will be compared to IF videos from me.
~ The conclusion will deduce whether FDS might need to replan IF’s takeoff length.

Introduction

Many airline pilots say that takeoff times vary depending on the altitude on the airport, temperature, weight of the aircraft and any deviation in the runway. This is conclusively true and the amount of time and length (ft) does vary depending on these variables. A retired airline Pilot, John Cox, said in a “USA Today” interview; “a twin-engine jet will have an average takeoff run of 30 – 35 seconds” he also said “It will vary depending on the altitude of the airport, the weight of the airplane and the outside temperature. The lift-off speed (VR) will also vary depending on the weight.” John Cox added that, “It is not uncommon for the ground run of a four-engine jet at heavy weights to exceed 50 seconds; this is due to the thrust-to-weight ratio being less.” These quotes obviously explain to us that 4 engine aircraft have a longer takeoff time, clearly due to being heavier and holding a much larger capacity of people, fuel and cargo,

If we were to have such a day that was perfect at an airport with 0 feet of altitude and with a runway that was completely level, we would be able to discover whether an overhaul is needed. Yes, fortunately we can have perfect weather conditions - 15°c, 0 winds and at visibility of 50km - in IF, however, this is not possible with the unpredictability of Earths climate and weather accord. Winds can change in seconds and I’m sure I will never be able to find this “perfect” day on YouTube showing specific aircraft that I will report on.
To the best of my 14 year old ability, I will create a fair test; using the required controlled, dependent and independent variables but this will not be University/College level. And, to be honest, I don’t think anybody could properly or perfectly discover the exact outcome.

Data

Data from Boeing and Airbus will be from their Airport Compatibility Page. If you would like to look at them yourself, tap/click on the required link and the PDF will be downloaded.

In this test I will be concluding on twin and quad engine jets. However, I will be mainly including Long Haul Jets, including;

  • 777-200lr
  • 777-300er
  • 787-8
  • 787-9
  • 747-400
  • A380-800

Let me know if there are any more longer ranged aircraft that you would like me to include

Now, onto the main part.

777-200lr

Now, we will be looking at the highlighted line, simply because it has the required weather conditions for my testing: sea level, 15°c, flaps 0.

Seen in this picture, as the weight becomes heavier, it has a longer takeoff field length. At MTW (766,000lb) the aircraft needs a longer runway length but at a airport at -4.8 degrees the air is so thin it wouldn’t need as much length, only speed.

From 1’18 to 2’18 the 777-200lr is taking off. This takeoff takes a full minute, there wouldn’t be - in any situation - where it would take a minute for an aircraft to takeoff in Infinite Flight.

Shown in this video that I have taken myself the takeoff of a MTOW 777-200lr takes 50 seconds. The video above from an amateur videographer shows that it takes up to 1 minute for it to full takeoff. I would think that for safety reasons that flight wouldn’t be at MTOW, making my point even clearer; the 777-200lr’s takeoff time should be longer.

image

YSSY’s 16R - 34L is 13030ft long. In this picture, however, the plane hasn’t even used 3/4 of the amount. At MTOW, the aircraft should probably use as much as that. It has used up to 8000ft. From the PDF file from earlier, it shows that it needs up to 10,000ft with those conditions and at MTOW.

777-300er

Coming soon

6 Likes

Just a random question, can you confirm the takeoff thrust used in your Infinite Flight video? Aircraft don’t all throttle up to 100% thrust for takeoff.

Taking into account pilot patience and consideration also in IF is a determining factor for a takeoff also, hope you’ve already considered this!

3 Likes

you also would need to take into account the amount of thrust the real plane is using compared to what youre using in the game, consideing theres no real way to find the real t/o thrust from the video its always gonna be different

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Hey mate! I used 90% takeoff thrust, equally to 100% on top of the power slider. I didn’t overuse the thrust.

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I understand. @DeerCrusher appears to be replying, and as a real world pilot, I’m sure he can tell you more than pretty much most other members on this forum!
Peace out ✌️

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Glad you brought this up as I was going to if someone hadn’t already. From what I understand the thrust generated by the engines for the various aircraft is equal to what you would find on the real world aircraft. The weight, drag, lift, thrust factors are all modeled in Infinite Flight from its real world counterpart.

If you find or recognize that an aircraft takes off much too soon in Infinite Flight, consider reducing power on the takeoff. Its likely that too much power is being used.

5 Likes

Don’t forget about aborted takeoff run out.

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That runway length that each aircraft lists isnt what is needed to get of the ground. It is the runway length to get off the ground and the length of runway it would use if it aborted takeoff at that weight below MTOW.

@DeerCrusher could it be safe to assume that older aircraft like the A380 and others wouldn’t have as accurate physics as the newer aircraft or their real-life counterparts? The 757 and 767 are a good example of this. There are often topics on the forum about how the physics are incorrect and they usually are closed after a response of something to the effect of “the aircraft is old. It will receive a rework soon”. Thoughts?

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You should probably test the A320 family and the CRJ family also, as those might have more accurate physics

N708DN DELTA 777-200LR Is an Atlanta to Tokyio flight. I can safely assume that video was taken in Atlanta as there is a delta crj in the background. Atlanta has super long runways and I would guess the throttle was set at about 80-85% and the aircraft was probably between 80-95% weight as it needs about 16 hours of fuel, assuming close to 291 seats sold, baggage, and a boat load of cargo. I think it’s pretty close

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Ah that is one reason why it won’t look exactly the same as unless you where in the actual cockpit for that flight you wouldn’t have exactly the same parameters set for the IF flight so you won’t get the same result.

IRL, as far as I can tell from talking to real life pilots as well as watching good old you tube, N1 rarely reaches 100% and so correct throttle more like 70-75%…

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The video was published before today and therefore that isn’t necessarily accurate. 80-95% is a big margin as well, but in my test takeoff from YSSY I used the full usable runway (with a stop margin) at about 76% throttle, flaps 5 and MTOW. The plane’s power parameters are more or less correct, if you apply them correctly. Even if they changed them, the takeoff roll wouldn’t change as the plane would still need the same amount of thrust behind it. Also remember, planes do not need to climb that fast at most airports, so as long as you can safely maintain any minimum climb rate set by the departure procedure (if you are using one), you can use as low of a power setting as possible, at least in a Boeing.

1 Like

Technically, yes you did over throttle. You shouldn’t using 90% of the slider. Instead use the N1%, which in any case wouldn’t go above the 90% area unless in an emergency.

I tested this with a 40% load just to see what % throttle should be used Vs N1% and it sits at around 75%.

Proof:

Screenshot_20180929-081757

Enjoy giving it another go, I’ve a feeling you will see a completely different result!

2 Likes

Would engine variants play some role in take off time?

I’d also recommend against using the A380 for your tests. Props for trying to make it less biased, but the A380 still features wonky physics like nose down cruising. You can safely eliminate it for the same reason as the A330 and A340. A better pick would be the A320 family instead.

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