Metal strips above airliner's doors.
"What size particles can be removed by the pneumatic system filters?"
"Gee, I dunno."
"The answer is 40 microns."
"Oh. How big is a micron?"
"Ahh..I don't know."
"Why do you want me to know how big 40 of the f*****s are?"
"Gee, I dunno."
"The answer is 40 microns."
"Oh. How big is a micron?"
"Ahh..I don't know."
"Why do you want me to know how big 40 of the f*****s are?"
Join Date: Nov 2001
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A roofrack... boy, till today I never could answer the Trainer Captains question of where to stow my ski's for winter holiday.
How many holes are there in the static ports? How many electric dischargers are attached to each wing? What is the use of the tiny blue + signs in the A320-cockpit?
I was asked those questions only a year ago, so much for the good old days!
P77
How many holes are there in the static ports? How many electric dischargers are attached to each wing? What is the use of the tiny blue + signs in the A320-cockpit?
I was asked those questions only a year ago, so much for the good old days!
P77
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OK, how is this for a guess BH:
When aircraft is flying in rain/cloud etc. water collected around the potable water access hatch and froze, lump of ice gets bigger and bigger until it falls off and falls through someones roof/head etc. also, on arrival at destination access hatch may be frozen solid and turnround time considerably extended whilst ice is chipped off/melts.
Solution: Put in a rain gutter that directs water away from access hatch and prevents ice forming?
When aircraft is flying in rain/cloud etc. water collected around the potable water access hatch and froze, lump of ice gets bigger and bigger until it falls off and falls through someones roof/head etc. also, on arrival at destination access hatch may be frozen solid and turnround time considerably extended whilst ice is chipped off/melts.
Solution: Put in a rain gutter that directs water away from access hatch and prevents ice forming?
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Gee, what's with you guys!
Imagine this OK.
The fuselage is like very round OK (as in "circular") in cross section (that's like a big slice of sausage, get the picture?).
Ok, now when it rains, where does the water go that lands on top of the airplane? It like goes AROUND the "circular" fuselage, as in sticking to the side, flowing down, running down, in like little riverlets of little water streams.
Ok, now imagine in the rain that the skybridge is at the gate, it's slowly being moved toward the door, slowly pressing in, slowing surrounding the door. Now imagine if the little rain gutter wasn't there. It would be like walking through a little waterfall to enter the plane's door, from the little riverlets of rain water flowing down and around the side of the plane. You can see this right?
Now for the 757, "potable" means "fit to drink". Imagine the little riverlets of rain water, flowing down and around the fuselage, running into the hose connections while loading the drinkable water. It would be like, you know, getting the water off of your car after you washed it, into your canteen.
Gee you guys....
Imagine this OK.
The fuselage is like very round OK (as in "circular") in cross section (that's like a big slice of sausage, get the picture?).
Ok, now when it rains, where does the water go that lands on top of the airplane? It like goes AROUND the "circular" fuselage, as in sticking to the side, flowing down, running down, in like little riverlets of little water streams.
Ok, now imagine in the rain that the skybridge is at the gate, it's slowly being moved toward the door, slowly pressing in, slowing surrounding the door. Now imagine if the little rain gutter wasn't there. It would be like walking through a little waterfall to enter the plane's door, from the little riverlets of rain water flowing down and around the side of the plane. You can see this right?
Now for the 757, "potable" means "fit to drink". Imagine the little riverlets of rain water, flowing down and around the fuselage, running into the hose connections while loading the drinkable water. It would be like, you know, getting the water off of your car after you washed it, into your canteen.
Gee you guys....
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As for daft questions:
Picture this, very respected, very well spoken ex BA 747 Flight Engineer teaching pressurisation and aircon at a ground school thats now skint.
For nearly four days the guy is going on about low and high pressure bleeds from the BRT, imagine all students frantically looking through their notes and index's for any mention of BRT!
BRT this, BRT that, for four full days.
Cause of massive discussion at lunchtime and over coffee, nobody wants to ask even though we are all desperate to know.
On the last day somebody asks the question
"Big round thing" comes the reply in this wonderful BA accent - whole class was pissing themselves for hours !!
Picture this, very respected, very well spoken ex BA 747 Flight Engineer teaching pressurisation and aircon at a ground school thats now skint.
For nearly four days the guy is going on about low and high pressure bleeds from the BRT, imagine all students frantically looking through their notes and index's for any mention of BRT!
BRT this, BRT that, for four full days.
Cause of massive discussion at lunchtime and over coffee, nobody wants to ask even though we are all desperate to know.
On the last day somebody asks the question
"Big round thing" comes the reply in this wonderful BA accent - whole class was pissing themselves for hours !!
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Potable water panel Gutter strip - my theory
Have a careful look at the belly area of a 757 aft of the main gear and you will invariably find a hydraulic fluid leak eminating from the centre hydraulic pumps.
Couple this leakage with the crap off the main gear and you have a rather unsavoury mix.
This fluid streaks down the centre of the fuselage and is redirected around the potable water service panel by the gutter strip, thus keeping the connections clean and skydrol free.
QED
Have a careful look at the belly area of a 757 aft of the main gear and you will invariably find a hydraulic fluid leak eminating from the centre hydraulic pumps.
Couple this leakage with the crap off the main gear and you have a rather unsavoury mix.
This fluid streaks down the centre of the fuselage and is redirected around the potable water service panel by the gutter strip, thus keeping the connections clean and skydrol free.
QED
Last edited by Golden Rivet; 11th Aug 2002 at 11:26.
Bottums Up
QAVION,
Your answer seemes emminently sensible and I was mindful of it yesterday whilst eating lunch, and looking at the starbord side of an A340.
If I can remember correctly, the door just forward of the wing and the overwing exit both had gutters which sloped down towards the front of the aircraft. I imagine that at a slight nose up attitude (cruise ?) this would have made the gutter close to parallel with the airflow.
The gutter above the aft service door however sloped down towards the rear of the aircraft, thus a small nose up attitude would have increased the amount of drag (negligible I know) from this gutter.
Any thoughts on why this is so?
Your answer seemes emminently sensible and I was mindful of it yesterday whilst eating lunch, and looking at the starbord side of an A340.
If I can remember correctly, the door just forward of the wing and the overwing exit both had gutters which sloped down towards the front of the aircraft. I imagine that at a slight nose up attitude (cruise ?) this would have made the gutter close to parallel with the airflow.
The gutter above the aft service door however sloped down towards the rear of the aircraft, thus a small nose up attitude would have increased the amount of drag (negligible I know) from this gutter.
Any thoughts on why this is so?
Last edited by Capt Claret; 13th Aug 2002 at 15:16.
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Capt Claret,
I believe that sloping rain gutters above doors are more effective at diverting water than gutters mounted parallel to the ground. They simply drain water faster. You'll notice that most all rain gutters above doors on airliners are sloped.
I believe that sloping rain gutters above doors are more effective at diverting water than gutters mounted parallel to the ground. They simply drain water faster. You'll notice that most all rain gutters above doors on airliners are sloped.
Bottums Up
Flight Safety
Understood, I think I've perhaps been misunderstood, or, I've misunderstood.
Qavion said:
My question to Qavion is why would gutters on the same side of the fuse, slope different ways, two down to the front, one down to the rear.
I understand the need for the slope when on the ground.
Understood, I think I've perhaps been misunderstood, or, I've misunderstood.
Qavion said:
The angle of the rain gutters is dependent on the airflow at that point on the fuselage (so that when the aircraft is flying at high speed, it offers the least amount of drag). This is why some slope down and some slope up
I understand the need for the slope when on the ground.
Last edited by Capt Claret; 14th Aug 2002 at 06:28.
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Because that's the direction of the airflow. In front of the wing, the airflow goes up as it goes aft, to get over the wing. Behind the wing, it goes down as it goes aft, because the air is lower pressure behind the wing.
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Cant believe it makes the slightest difference in performance if the slope of the rain getter is up or down !
Have a look at the CDL just to see how many bits may be missing on the airplane with 'negligible' performace penalty.
Have a look at the CDL just to see how many bits may be missing on the airplane with 'negligible' performace penalty.