737-700 vs 737-800
Joined: Jan 2006
Posts: 2,205
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From: US
Glide ratio of 22:1? Where'd you get that number from?
V2+20???? 24K motor, 140,000 lbs, Flaps 5 V2 approx. 145 kts. Flaps 15 V2 approx. 140 kts. Using your technique works out to 160-165 kts when the actual L/D glide speed is 211 (QRH).
Other techniques for computing basic L/D glide speed (actual speed is in the QRH for dual engine failure) -
GW + 70-75 kts (+75 light, +70 heavier) -
140,000 lbs + 70 = 210. QRH speed is 211.
120,000 + 75 = 195. QRH speed is 195.
Or Vref 30 + 65.
V2+20???? 24K motor, 140,000 lbs, Flaps 5 V2 approx. 145 kts. Flaps 15 V2 approx. 140 kts. Using your technique works out to 160-165 kts when the actual L/D glide speed is 211 (QRH).
Other techniques for computing basic L/D glide speed (actual speed is in the QRH for dual engine failure) -
GW + 70-75 kts (+75 light, +70 heavier) -
140,000 lbs + 70 = 210. QRH speed is 211.
120,000 + 75 = 195. QRH speed is 195.
Or Vref 30 + 65.
Joined: Mar 2011
Posts: 1,407
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From: engineer at large
For the most part, I see much more, and harder braking on the 800, simply that it is much easier and cheaper to cycle the brakes, than the engines...
Passengers get an E ticket ride on that landing...
Does a damn-damn on the runway of course.
Passengers get an E ticket ride on that landing...
Does a damn-damn on the runway of course.
Last edited by FlightPathOBN; 20th June 2012 at 21:14.
Joined: Jan 2006
Posts: 2,205
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From: US
Are you figuring out TAS? I came up with 19.5 (+/-).
787 was trying for 21:1. I think I read that it came it an 22:1.
I doubt the 737NG is as efficient as the 787.
Manual gives a distance estimate for a fixed altitude. That's 18:1, but it doesn't talk about what the maximum is.
787 was trying for 21:1. I think I read that it came it an 22:1.
I doubt the 737NG is as efficient as the 787.
Manual gives a distance estimate for a fixed altitude. That's 18:1, but it doesn't talk about what the maximum is.
Last edited by misd-agin; 21st June 2012 at 20:38.
Joined: Sep 2008
Posts: 61
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We fly both 700 & 800 and I personally like the 800 more. I feel in turbulent conditions on approach the 800 is less thrown around, more attitude stable.
Some differences in flying:
- descent planning: At usual descent weights the 800 will descent less fast than the 700 and correcting too much height is also more difficult in the 800. This has to do with the 800 having being heavier but having the same wing. If you look at a D-EAS curve a 700 doing 300kts in descent has more drag than an 800.
- flare: the 800 requires less flare than a 700. If you flare the 800 like a 700, you touch down 1000m into the runway
- be prepared for tailwind: be conservative when flying an approach with tailwind as the 800 does not slow down on approach with tailwind (config UP to F5).
Some differences in flying:
- descent planning: At usual descent weights the 800 will descent less fast than the 700 and correcting too much height is also more difficult in the 800. This has to do with the 800 having being heavier but having the same wing. If you look at a D-EAS curve a 700 doing 300kts in descent has more drag than an 800.
- flare: the 800 requires less flare than a 700. If you flare the 800 like a 700, you touch down 1000m into the runway
- be prepared for tailwind: be conservative when flying an approach with tailwind as the 800 does not slow down on approach with tailwind (config UP to F5).
Joined: Apr 2002
Posts: 3,349
Likes: 1
From: FUBAR
If you fly an 800 with the short.field-performance kit fitted, intermediate appr gets a whole lot harder, as you will not have full ext on the LED's until F30.
My previous "best -friend" F10, is now useless, new "best-friend" is the LG which I am using a LOT earlier than in the "normal" 800's.
My previous "best -friend" F10, is now useless, new "best-friend" is the LG which I am using a LOT earlier than in the "normal" 800's.
