The 777 is overpowered (with real data to prove it)

[Username_pending]

I have always felt that, since the 777 was reworked 6 years ago, it has been far more powerful during the climb than the real thing. I understand that the developers won’t and can’t update the performance characteristics of an aircraft based on feelings or assumptions, so I have done my best to accumulate some real data. This includes data from a LATAM 777-300ER Flight Crew Operations Manual (link below) and a video from inside the cockpit of a real departure. Hopefully the data provided in this thread is enough to update the performance of the 777 to make it as accurate as possible.

Part 1 :

Data from the FCOM of a LATAM 777-300ER :

https://studylib.net/doc/25610915/fcom-v1v2-b777-latam-brasil-rev24–tpr-41-rev-1-

This table from the FCOM shows us the maximum climb thrust available at given altitudes and temperatures. I have highlighted the figures significant to this test.

The table below shows us the climb rate, speed and pitch we should expect at full climb thrust at given altitudes and temperatures. Once again I have highlighted the relevant data for this test.

Therefore if we combine the two we are able to get the maximum climb rate we should expect at each weight and at each altitude.

The weight was set to 310t.

10,000ft : TAT is 10 degrees C

93% N1 set as per the chart

Expected climb rate : 2700ft/m pitching at 9.5 degrees and stable at 270kts

IF climb rate : 4400ft/m with speed increasing

Difference : 1700ft + speed should have not have been increasing :

To maintain the rate of climb and speed expected I had to lower the nose to 6/6.5 degrees (3 degrees lower) and the N1 to 78% (15% lower than expected.) :

20,000ft : TAT is -5 degrees C

96% N1 set as per the chart

Real expected climb rate : 1900ft/m pitching at 7.5 degrees and stable at 270kts

IF climb rate : 3900ft/m pitching at around 7.5/8 degrees with correct speed

Difference : 2000ft/m

30,000ft : TAT is -15 degrees C

100% N1 set as per the chart

Real expected climb rate : 1200ft/m pitching at 4.5 degrees at 280kts

IF climb rate : 2300ft/m at 4.5 degrees and speed correct

Difference : 1100ft/m

How much higher is IF 777 climb performance than reality :

10,000ft : 63% too high

20,000ft : 105% too high

30,000ft : 92% too high

This shows that during the climb the 777 is between 60%- over 100% too capable and too powerful, depending on the altitude.

Part 2 :

Video of Turkish Airlines 777-300ER departure.

Turkish Boeing 777-300ER Cockpit Istanbul🇹🇷 to Tokyo Narita🇯🇵

I matched all weight, weather and power information seen in the video to a departure I did in IF to track the difference. You can see these values below with time stamps for when they are visible in the video.

Temperature : 11 degrees on departure (22:00)

Weight : 324.5t (28:00)

Performance vs IF

Real 777 : climbing at 2400ft/m at 10,000ft and at 250kts when pitching at 10 degrees with 93% n1 (37:50)

IF 777 : climbing at 3600ft/m at only 88% n1 at same speed and altitude

Difference : 1200ft/m at 5% less N1

Real 777 : Climbing at 2300ft/m at 15,000ft and at 320kts whilst pitching at ~6/6.5 degrees (39:50)

IF 777 : climbing at 3500ft/m at only 88% n1 (if you match the n1 to the video the IF version can do over 4000ft/m)

Difference : 1200ft/m at 8% less N1

Conclusions :

It’s clear to see that the 777 on IF has much better climb performance than the real counterpart. The pitch when climbing isn’t too dissimilar so it appears to be a mixture of producing too much lift, and the engines being too powerful (or the aircraft not producing enough drag.) I understand that differences of 1000-2000ft/m don’t seem too big, but that represents between 62% and over double what the 777 is actually capable of. The 777 is a great airliner capable of carrying some incredible weights, it would be great if it could feel like the heavy airliner that it is in the sim.

Before anyone accuses me of moaning or hating, that is not the purpose of this topic. The 777 is a great aircraft and is one of the most popular in the simulator, I want to help make it as accurate as possible. I hope this is useful in that cause!

[Maxim.k42]

Not sure if you are aware… You did not insert any actual images.

[Username_pending]

Just working on it ahahahahah. Thanks for letting me know!

[Username_pending]

Ok, they should all be in now!

[Nawf]

Really wonderful topic, I must say. It is extremely detailed with evidences to support the claims which Laura would most definitely appreciate since she needs something yo work off of, which you gave.

The 777 is one of my favorite aircrafts IRL but personally I tend to fly the A359 even though the 777 is more detailed and etc. since it’s overpowered (big driver for me since takeoff and climbing to cruise is on of my favorite phases of flight).

Hopefully the topic catches the eye of a dev and is taken into account, even for the future.

[Username_pending]

Thank you, I am also a big fan of the 777 and that’s why I felt compelled to write this topic. I also really enjoy the takeoff and climb but find it difficult to look past the 777s ability to go space shuttle status, even when heavy.

The 777 is a very powerful aircraft, but it uses that power to carry a shed load of weight. And when it’s at those higher weights it climbs like any other heavy airliner, it would be amazing to have that reflected in the sim.

[XddDragon529]

@Username_pending

producing too much lift, and the engines being too powerful (or the aircraft not producing enough drag.)

Yes. In the lift-drag area, I’ve already found out that L/D max is greatly inflated. At MTOW, the Vmd speed is at 332 KIAS, even higher once compressibility effects start to chime in going higher. This speed gives a higher climb rate than what the FCOM figures suggest. If you paired maximum climb n1 with that speed, that’s a lot more in climb rate, and Vmd is not even supposed to be for best climb rate. It’s a speed higher than that.

[Username_pending]

Good knowledge! That would make a lot of sense and match up with what the manual and the video seem to suggest. Hopefully this can be fixed relatively easily (In similar fashion as when the A330s drag figures were altered.)

[XddDragon529]

They didn’t alter the drag. They just gave the plane more thrust. I know this because the Vmd speeds remained the same after changes. The only difference is with more excees thrust, you can have higher climb rates, initial cruising altitudes, and/or faster cruise speeds.

AndrewWu did indicate a higher initial altitude in his guide with the A330, but I test differently. I do Vmd until I determine the optimum altitude with range (TAS × Fuel Time), then speed up in flight to determine the optimum cruise speed. Somtimes, that works out better, worse, or on par with what he gives. If it so happens that there’s a known cruising altitude for specific circumstances and I can’t hit that at Vmd while reaping efficiency, then I know that’s some sort of logic/coding error on IF’s part, not mine.

One instance I recall is the MD-11 that also has a Vmd at 332 KIAS like the B77W, but doesn’t make it to 35,000 feet. You have to keep reducing Vmd to a slower speed to keep climbing, which is not what you’re supposed to do with Vmd as you go higher. Same case may apply to the 777 family.

[Username_pending]

Forgive my ignorance, but how do you calculate Vmd?

[XddDragon529]

I make it easy and start off at ISA conditions close to sea level. Keep increasing or decreasing flight speed in KIAS and observe the speed that gives the greatest fuel time/least fuel burn/n1.

[XddDragon529]

If you’re ever curious, you can always check this right here:
My OEI and Vmd Performance Data Findings
It already has extensive information about the Vmd speeds for most of the IF aircraft with each flap configuration.

[Username_pending]

Very interesting! Hopefully the developers are able to use this and other data to correct the 777s performance, because right now it climbs like Artemis II.

[IFflyer]

It sure Is. Even at relatively higher loads, I sometimes takeoff with this thing on 70% power, and it would still takeoff very smoothly lol.

[Username_pending]

I once put it 10t above its MTOW and put the temperature to 70 degrees. It very happily climbed at well over 3000ft/m at only 78% throttle!

[Veloist]

Great data and insight! I think a lot of users who regularly fly the 777 know that it’s overpowered, especially those who want to chase a realistic take-off and climb-to-cruise profile.

Personally on routes I’ll fly, I review past flight data on Flightradar24 & eyeball V/S’s on those phases, and monitor ground speed (since we never really know the actual airspeed of a flight).

Based on data available to me on FR24, I find that I can get really close to the typical climb rates and I usually use a real-life flight’s altitude at certain waypoints to confirm them.

Doing so involves occasional manual thrust & V/S adjustment…but given how powerful the 777 in IF, it’s only in small increments. It’s not as realistic as one might want, but it works for me because at the end of the day I’m more satisfied spending the same amount of time climbing to cruise as a real-life flight.

Plus we don’t have autothrottle.

[Username_pending]

I understand your point as you are able to climb slower if you wish, it just requires very low attitudes and power settings. It’s quite difficult to explain, but to me part of the appeal of flying the 777 is that when it is heavy it will climb slowly and take a lot more effort to get up to cruise. You will spend more time flying lower, building speed and feeling as if you are pushing the aircraft to the limits of what it is capable. Right now, even when above its MTOW, it flies as if it’s empty, in my opinion that defeats the purpose of adding a heavy airliner to the sim.

[German-Invasion]

I wonder if this is the same with the B77L?

[Anthony_Gulluscio]

Really interesting topic.

And it’s cool to see a fellow looking at FCOMS. I’m making a fictional JetBlue one right now myself

If you’re curious

Part of a real one

[Username_pending]

I would guess that it probably is but I’m not sure as I haven’t tested that one yet. This thread that I found seems to suggest that it is :

Do aircraft in Infinite Flight have way too much power? The numbers say…

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I wonder if this would be something that could be fixed quite easily or if it would be more difficult? If it was difficult that would explain why the developers seem quite hesitant to do it.