m1m2 From Canada, joined Dec 2011, 137 posts, RR: 0
Reply 2, posted (3 years 4 months 2 weeks 2 days 15 hours ago) and read 13209 times:
Same here, and I work on aircraft that fly several cycles a day. I don't think they get used that much, probably just occasionally during taxi and sometimes when landing. Not sure about the take off roll, maybe some of our pilot friends here can help us with that.
yeelep From United States of America, joined Apr 2011, 819 posts, RR: 0
Reply 3, posted (3 years 4 months 2 weeks 2 days 14 hours ago) and read 13151 times:
Up until a couple of years ago we rarely changed them. Now they are changed every year as part of a winter prep task card. I also will replace one when changing a window due to scratches on the outer pane.
A320ajm From United Kingdom, joined May 2006, 659 posts, RR: 0
Reply 4, posted (3 years 4 months 2 weeks 2 days 12 hours ago) and read 13095 times:
Not to hijack this post but....
When I was young, 14 or 15 perhaps, I asked my flying instructor (who now works for a UK low-cost airline) if commercial aircraft had wipers. He looked at me and laughed like it was a stupid question, and said he didn't think so. This post just reminded me of this time And probably now is the first time I've ever thought about them having windscreen wipers!
If the British Empire and its Commonwealth last for a thousand years, men will still say, 'This was their finest hour.'
CCA From Australia, joined Oct 2002, 927 posts, RR: 14
Reply 5, posted (3 years 4 months 2 weeks 2 days 12 hours ago) and read 13070 times:
When ever its raining and you can't see the taxiways or runway well enough they get used, it depends on the severity of the rain and the speed of the aircraft, as you can imagine light rain at high speed is similar to heavier rain at slow speed.
The windscreens are also treated with a hydrophobic coating which repels water, I've asked for reapplication of the coating more times that I've written wipers up in the tech log. Most times the wiper just fails but its rare, 747 wipers seem to be very good.
On the 737's the answer is no and kinda. up to the NG's they have a fluid system like a cars. But instead of a washer type fluid, a product called Rainboe (think industrial strength Rainex) is sprayed. The NG's have none.
musang From United Kingdom, joined Apr 2001, 920 posts, RR: 6
Reply 13, posted (3 years 4 months 2 weeks 1 day 14 hours ago) and read 12556 times:
Very interesting replies from mechanics.
I drive 737s, short haul of course, and I would guess I snag one maybe three times a year, always because the contact edge (the approx 2mm wide strip) is ripping off the main blade body.
No rain repellant is used at all, engineering dept confirm this is company-wide, and thinks its also nationwide, because of the carcinogenic nature of the stuff. 146s had a "Rainboe" repellant spray system, but it was deactivated before I got to them.
No hard stats available but the technician I spoke to estimates they change one blade a month on a fleet of about 30.
No wiper speed limit on 737s but they are difficult to park (against the airflow) above about 180 knots. They aren't needed as soon as you leave the ground, so are routinely parked immediately. On a rainy approach, airspeed is low enough such that the airflow does not overpower them.
I saw cockpit pics in an article on 727s with a South American operator, which showed the blades parked in the vertical position rather than horizontal. Why would they decide to do this? Could anyone offer an opinion on why this isn't standard on all types (it is on some commuters). On 727/737 the first places ice builds up on the front screen is top of the centre pillar and the lower outer corners, so the outer end of the parked blade would be susceptible in either of the two park positions. Having said that though, in years of 737 ops I've never seen ice restricting the blade when I needed to operate
Bellerophon From United Kingdom, joined May 2002, 586 posts, RR: 58
Reply 17, posted (3 years 4 months 2 weeks 1 day 10 hours ago) and read 12451 times:
...Not sure about the take off roll, maybe some of our pilot friends here can help us with that...
Just as a piece of trivia, in general, most on the Concorde fleet were reluctant to use windshield wipers on the take-off roll.
When raising the visor, there was only a small amount of clearance between a correctly parked wiper blade and a moving visor at the best of times. If, when you turned the wipers off they did not park themselves perfectly, they could foul the visor as it came up and prevent it from being raised fully.
If the visor couldn't be raised fully, you couldn't go supersonic, so jettison fuel and return to base!
On balance, most never used them on take-off, other than during the heaviest rainfall.
dlednicer From United States of America, joined May 2005, 558 posts, RR: 6
Reply 20, posted (3 years 4 months 2 weeks 1 day 2 hours ago) and read 12319 times:
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Quoting musang (Reply 13): I saw cockpit pics in an article on 727s with a South American operator, which showed the blades parked in the vertical position rather than horizontal.
DC-10s have blades that park in the horizontal position, while on the MD11, the blades park in the vertical position. On DC-10s rebuilt as MD10s, the blades also park in the vertical position. Its a minor drag reduction item.
musang From United Kingdom, joined Apr 2001, 920 posts, RR: 6
Reply 21, posted (3 years 4 months 2 weeks 22 hours ago) and read 12245 times:
Quoting b78710 (Reply 15): Our jumbos have windscreen wash, in a little bottle in a stowage behind the captains seat
And 146s / Avro RJs. Pushbutton on the overhead, we could usually hear the pump, which sounded like a car washer pump, and it took a good few seconds for the fluid to climb the 4 feet of tubing to the nozzle, i.e. the one way valve didn't work!
amccann From United States of America, joined Mar 2008, 175 posts, RR: 0
Reply 24, posted (3 years 4 months 2 weeks 1 hour ago) and read 11958 times:
Quoting dlednicer (Reply 20): DC-10s have blades that park in the horizontal position, while on the MD11, the blades park in the vertical position. On DC-10s rebuilt as MD10s, the blades also park in the vertical position. Its a minor drag reduction item.
I think early MD11s were delivered with blades that parked horizontally. I know the switch to vertically parked blades was a two fold effort to reduce cockpit noise and reduce drag as part of the performance improvement program for the MD11.