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-   -   777X set for January 23rd first flight (https://www.pprune.org/rumours-news/629048-777x-set-january-23rd-first-flight.html)

Longtimer 26th Jan 2020 20:38


Originally Posted by Auxtank (Post 10672336)
With the gear down - it would be...
Under 270 KIAS actually...(and probably well under that..)

Thanks, I know that limit is for gear extension but was curious as to what the max operating speed would be with the gear staying down. Mind you flight tracker is not always completely accurate. Thanks

Cough 26th Jan 2020 20:44

I wondered how much they increase Vr for safety? It's noticeable that the front wheel of the MLG rises prior to rotation (I imagine for two reasons - The wing was ready and also the semi levered landing gear is ready to give it a shove off the ground) it just left me wondering what the margin is?

DaveReidUK 26th Jan 2020 22:05


Originally Posted by Longtimer (Post 10672344)
Thanks, I know that limit is for gear extension but was curious as to what the max operating speed would be with the gear staying down. Mind you flight tracker is not always completely accurate.

Even if it's accurate, it won't give you KIAS or KTAS, only groundspeed.

Longtimer 26th Jan 2020 23:26


Originally Posted by Cough (Post 10672349)
I wondered how much they increase Vr for safety? It's noticeable that the front wheel of the MLG rises prior to rotation (I imagine for two reasons - The wing was ready and also the semi levered landing gear is ready to give it a shove off the ground) it just left me wondering what the margin is?

I had read somewhere that there concerns with the added length causing tail strikes and then in another article is was pointed out that the new wing had better lift so perhaps that is why the main gear lifted first.

Smilin_Ed 27th Jan 2020 17:22

"You can bet if an engine failure occurred on takeoff they would have raised the gear."

In military test pilot schools, it is taught that you keep the gear down while going through all the other tests that must be done on first flights. As for what to do if you lose an engine on a first flight, they were probably pretty light so they might not pull it up even then. Just my thinking. In any case gear movement is a massive thing. The KISS principle applies. Keep It Simple, Stupid.

krismiler 28th Jan 2020 06:27


Boeing sees the new 777X as a ray of hope, but it emerged from the same culture of cutting corners and coverups that gave us the MAX crisis.
https://www.ccn.com/i-would-never-fly-boeings-new-777x/

stilton 28th Jan 2020 08:35


Originally Posted by Longtimer (Post 10672344)
Thanks, I know that limit is for gear extension but was curious as to what the max operating speed would be with the gear staying down. Mind you flight tracker is not always completely accurate. Thanks


Boeing no longer has separate limiting speeds for gear retraction/ extension/ extended as they did in the past


They have standardized on 270/.82 for all three


RexBanner 28th Jan 2020 08:59


Originally Posted by stilton (Post 10673513)
Boeing no longer has separate limiting speeds for gear retraction/ extension/ extended as they did in the past


They have standardized on 270/.82 for all three

Have they announced what speed this beauty is going to cruise at yet?

3Greens 30th Jan 2020 21:49


Originally Posted by RexBanner (Post 10673537)
Have they announced what speed this beauty is going to cruise at yet?

they won’t know for sure until the flight testing programme is complete.

tdracer 30th Jan 2020 23:39


Originally Posted by RexBanner (Post 10673537)
Have they announced what speed this beauty is going to cruise at yet?

Pretty sure the target is Mach 0.84 - 0.85, but as 3Greens notes, the flight test results will be the final determination.


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