Gliding in a 777, 747 etc...Can it be done.?
Joined: Nov 2000
Posts: 142
Likes: 47
From: Montgomery, NY, USA
Question for Mastergreen. Are the calculations you use different for a fuel starved engine rather than throttles at idle? My point being that an engine at idle is still providing the power to "windmill" itself whereas a fuel starved engine is probably windmilling due to the aircraft's forward speed and causing drag as it does, decreasing your range. And how about where all engines are seized up, as happened to an Eastern Airlines L1011 back in the 70's. If the engines can't turn, how much more drag does that induce? (They were able to get one re-lit and make it back to Miami, only to have it shut down right again after landing.)
Joined: Feb 2000
Posts: 120
Likes: 0
From: New Zealand
patrickal
Nice of you to use the word "calculations" but I am not bright enough for that by far. All my numbers are ex simulator practise.
That said, as far as I can figure the numbers I stated above are for a windmilling motor. You comment about the stalled / static N1 is valid and is an added complication. However I thought of this when I ran it through the systems and the SIM at least gave me enough spare to allow the technique as written enough flex to make it down.
The question about glide angle is valid (on the face of it), but I would caution restraint in comparing a 200,000 Kg swept wing 777 with a Blanik or a Plastic Pig (Astir) . Sure you have a couple of 9 ft windmilling fans and a RAT hanging out, but there is a an awfull lot of potential energy there that needs burning off.
300+ ft per mile is not a problem clean (zero wind) and as I mentioned - get into a 400ft / mile profile before you dump flap to 5. This is easy as .....
I am not trying to invent an SOP here. I am just trying to float a few ideas. Get into the box and try it. What I proposed works for me, but if you have a better mouse trap - I am first in the queue. Gimme.....
MG
[ 12 August 2001: Message edited by: MasterGreen ]
Nice of you to use the word "calculations" but I am not bright enough for that by far. All my numbers are ex simulator practise.
That said, as far as I can figure the numbers I stated above are for a windmilling motor. You comment about the stalled / static N1 is valid and is an added complication. However I thought of this when I ran it through the systems and the SIM at least gave me enough spare to allow the technique as written enough flex to make it down.
The question about glide angle is valid (on the face of it), but I would caution restraint in comparing a 200,000 Kg swept wing 777 with a Blanik or a Plastic Pig (Astir) . Sure you have a couple of 9 ft windmilling fans and a RAT hanging out, but there is a an awfull lot of potential energy there that needs burning off.
300+ ft per mile is not a problem clean (zero wind) and as I mentioned - get into a 400ft / mile profile before you dump flap to 5. This is easy as .....
I am not trying to invent an SOP here. I am just trying to float a few ideas. Get into the box and try it. What I proposed works for me, but if you have a better mouse trap - I am first in the queue. Gimme.....
MG
[ 12 August 2001: Message edited by: MasterGreen ]
Couldonlyaffordafiver
Joined: Dec 2000
Posts: 1,934
Likes: 0
From: The Twilight Zone near 30W
I think, when it all goes quiet, all credit to anyone who can make it to an airfield and walk away from it. Well done to the Transat guys!!
As far as Capt EM doing his damnedest to get them going again, I think he managed with some of them ...... bet he was glad he had four to choose from!!
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You can only have too much fuel when you're on fire ...........
As far as Capt EM doing his damnedest to get them going again, I think he managed with some of them ...... bet he was glad he had four to choose from!!
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You can only have too much fuel when you're on fire ...........
