Why Don't LightPlanes Have Winshield Wipers?
Richard Kaplan
Clearly it isn't a good idea to fly in the rain if a pilot is
only VFR rated, but I would think wipers would help in light
rainshowers. More importantly, how does an IFR pilot in a C-172
see through his windshield after getting wet in a cloud?
--
Richard Kaplan, M.D. Voice: (507) 281-1689
806 2nd St. SW Apt. 104 Data : (507) 281-1989 14.4K HST
Rochester, MN 55902 (Medical Software Exchange BBS)
rka...@umbio.med.miami.edu
Kevin R. Kirtley (SVER)
>I guess the title says it all.
>
>Clearly it isn't a good idea to fly in the rain if a pilot is
>only VFR rated, but I would think wipers would help in light
>rainshowers. More importantly, how does an IFR pilot in a C-172
>see through his windshield after getting wet in a cloud?
>
windshield. If the rain is so heavy that it wont blow off then your flight
visibility is probably too low to be legal or below minimums. Flying through
light rain showers is fun: you can see some of the airflow patterns on the
aircraft. In particular, you can sometimes see the laminar-to-turbulent
boundary laryer transition on your lift struts.
Kevin R. Kirtley
Short Wing Piper Lover
William LeFebvre
|> Light planes don't need windshield wipers 'cause the rain just blows off the
|> windshield. Flying through
|> light rain showers is fun: you can see some of the airflow patterns on the
|> aircraft....
I'll second that. The first (and so far the only) time I flew in to
a rain shower (yes it was light), it rattled me for a moment. I was
a student on a solo cross country. I had gotten a very thorough
briefing (which did not mention a chance of rain). Because of
clouds and turbulence I considered the conditions marginal for my
abilities but I decided to go up and "have a look" anyway.
When I hit the rain, my first thought was "is this legal? Can I fly in
the rain?" And that's what rattled me. I thought very hard for a few
seconds and decided that as long as my clouds and visibility were above
minimums I was legal. Once I calmed down it was fun to watch the rain
get blown off the windshield by the prop. That was when I learned why
single engine planes don't have wipers.
The shower didn't last very long, but the turbulence got worse and the
clouds continued to threaten. After going about 20 miles I turned back.
I'm glad I went up, but I'm also glad that I decided to turn back.
William LeFebvre
Computing Facilities Manager and Analyst
Department of Electrical Engineering and Computer Science
Northwestern University
<ph...@eecs.nwu.edu>
Donovan Hammer
experience ;-) .
In the Pacific NW, a pilot flys in rain 6 months out of the year. A light rain
simply blows off at essential any air speed that you're likely to be flying.
Even a moderately heavy rain shower will blow clear at cruise speeds, but may
accumulate somewhat at slower speeds such as in the pattern.
It is important to note that visibility at downward angles such as out to the
side and down remains clearer than directly forword (due to the fact that you
can see down along the rain or snow fall better than at a right angle to the
rain fall and due to the fact that the side windows remain free of rain drops).
If the rain is so heavy that it creates further accumulation problems, then the
pilot screwed up with his preflight planning and he's below VFR minimums (and
that's a "no-no").
Don Hammer
dono...@sptekwv1.wv.TEK.COM
Tektronix, Computer Graphics Group
Wilsonville, Oregon
Rob Farlee
>I'll second that. The first (and so far the only) time I flew in to
>a rain shower (yes it was light), it rattled me for a moment.
the first time it rains and the OAT is, say, 26 F, it will rattle you, too!
one definite advantage of Cessnas is that even if the windshield is
covered with ice, you can always open up the side window and stick your
head out to see the runway when you turn final. i'd hate to land a
post-pacer-piper with an iced-over windshield...
--
The UUCP Mailer
Ed Hutton
>More importantly, how does an IFR pilot in a C-172
>see through his windshield after getting wet in a cloud?
Well at 100 mph it just blows off the windscreen. You can help improve
your visibility a bunch by using an amazing product called Rain-X. This stuff
is great. Clean the wind screen real well, spread the Rain-X on, let it dry
to a dull haze, and buff off. You can try it out on your car. At highway speeds
you don't need windshield wipers! Anyone else using this stuff? We've been
using it for about a year now and haven't had any problems with it.
Ed
--
ed.h...@ncrcae.Columbia.NCR.COM (Ed Hutton)
...!uunet!ncrlnk!ncrcae!hutton ...!gatech!hubcap!ncrcae!hutton
Bill Carpenter
hutton> product called Rain-X. This stuff is great. Clean the wind
hutton> screen real well, spread the Rain-X on, let it dry to a dull
hutton> haze, and buff off. You can try it out on your car. At highway
There is a brief evaluation of Rain-X in the just-arrived (August?)
_Consumer Reports_. They thought it was basically okay but had a few
minor drawbacks (e.g., didn't last as long as advertised, etc).
--
Bill Carpenter att!hos1cad!wjc or attmail!bill
Ron Wanttaja
> >only VFR rated, but I would think wipers would help in light
> >rainshowers.
> >
> windshield.
Or, in the case of the Fly Baby, it blows to the top of the windshield,
turns the corner, then slides down the INSIDE of the glass to the top of
the instrument panel. I need wipers on both sides....
| "Glub!"
_|_/
/":"\
-------:==^==:-------
[[| o |]]
-----------------__________\_____/__________-----------------
_ / \ _
T T/_______\T T Ron Wanttaja
| | | | prang@ssc-bee
""" """ pr...@ssc-bee.boeing.com
Mark Stolz
Since the plane is moving at a rather rapid rate, any water on the
windscreen clears off very quickly. In the rain that I have been in,
both in the air enroute and on the approach, there has not been any
problem with being able to see out the windscreen because of water (
At least in the liquid form, the frozen stuff was a real pain one day)
Chris Bryden
}In the Pacific NW, a pilot flys in rain 6 months out of the year. A light
}rain simply blows off at essential any air speed that you're likely to be
}flying .
Say, has anyone tried using Rain-X on the aircraft windshields? When I
drove out to the west coast, the stuff was invaluable. I don't believe I
used the windshield wipers much at all, and this is at speeds below 70mph
(but not by much). The bugs were easier to get off the windshield, as well.
--
{gateway}!udel!brahms!bryden | I am a direct result of the policies and actions
bry...@udel.edu 302-451-6339 | that are endorsed by the University of Delaware.
Dr. Daniel R. Masys
>
>If the rain is so heavy that it creates further accumulation problems, then the
>pilot screwed up with his preflight planning and he's below VFR minimums (and
>that's a "no-no").
>
the trade. Then I would add that there is a fairly dramatic and common
situation where you are droning along in clouds with the rain comind down
so hard that it sounds like buckets of marbles being thrown at the
windshield. At this time you will not see it, however, because your eyes
will be in hyperdrive doing the IMC instrument scan dance. Often in this
situation the pilot chooses not to look up in any case, since he knows he
will not like what he sees (dark dark grey).
So this is another reason the plane doesn't need windshield wipers. :-)
Dan Masys
ma...@mcs.nlm.nih.gov
Christopher Pettus
>simply blows off at essential any air speed that you're likely to be flying.
>Even a moderately heavy rain shower will blow clear at cruise speeds, but may
>accumulate somewhat at slower speeds such as in the pattern.
OK, now I'm curious. If this is true (that rain blows off at any
reasonable speed), why do airliners (at least Boeing 737s) have
windshield wipers? No prop to blast the rain away? Then what
about twins?
--
-- Christophe
"Oh, so you're going to kill me! What a finely-tuned response to the
situation!"
Donovan Hammer
>OK, now I'm curious. If this is true (that rain blows off at any
>reasonable speed), why do airliners (at least Boeing 737s) have
>windshield wipers? No prop to blast the rain away? Then what
>about twins?
>--
>-- Christophe
I don't have a good answer for that, but I suspect it's for several reasons:
1) On my SEL aircraft, I can reach my wind shield to wipe off
dew/condensation, bug splats, etc. However, the wind screen is
less accessable on an aircarrier type aircraft.
2) Because they can afford to have them - may actually be a requirement
for Part 135 and Part 121(?).
3) They're for de-icing (i.e. freezing rain).
Anybody know this one?
Don Hammer
dono...@sptekwv1.wv.TEK.COM
Tektronix, Computer Graphics Group
Wilsonville, Ore.
Don Elton
When the rain stops blowing off the windshield you call it ice.
Ron Wanttaja
> >More importantly, how does an IFR pilot in a C-172
> >see through his windshield after getting wet in a cloud?
>
> Well at 100 mph it just blows off the windscreen. You can help improve
> your visibility a bunch by using an amazing product called Rain-X. This stuff
> is great. Clean the wind screen real well, spread the Rain-X on, let it dry to
> a dull haze, and buff off. You can try it out on your car. At highway speeds
> you don't need windshield wipers! Anyone else using this stuff?
I tried it on my car, and was less than impressed. It does make the rain
bead up, but leaves a streaky film which is distracting at night. Consumer
Reports recently had an article on it, where they said about the same
thing. It probably works pretty good on an airplane, which won't have
headlights glaring off the windscreen.
Then again, many people swear by Lemon Pledge...
Ron Wanttaja
prang@ssc-bee
...rutgers!uw-beaver!ssc-bee!prang
pr...@ssc-bee.boeing.com
Wolfgang Diestelkamp
In article <55...@apple.Apple.COM>,
c...@Apple.COM (Christopher Pettus) asks:
> OK, now I'm curious. If this is true (that rain blows off at any
> reasonable speed), why do airliners (at least Boeing 737s) have
> windshield wipers? No prop to blast the rain away? Then what
> about twins?
When I talked to a Lufthansa captain about this once, he told me they
didn't need it in flight, just for taxiing :-).
--
===============================================================================
| Wolfgang Diestelkamp |
| please don't mail to the indicated return address, it might be fake. |
| mail to 'wolf...@gmdtub.uucp' |
===============================================================================
hend...@esvax.hamavnet.com
Perhaps they use the windshield wipers while they're on the ground (I don't
think you need any reasonable airspeed there...) Just a thought.
--
Javier Henderson | hend...@esvax.hamavnet.com | Wherever you go,
Avnet Computer | decwrl!hamavnet!henderson | there you are.
Los Angeles, CA | |
Eric Struble
I have been using Rain-X for about 5 years and have been pleased with the
results.
I first read about in AOPA Pilot when they did an article on windshields.
PPG, the largest manafacture of windshields, recommended it. The only thing
I found objectionable was the fact that at night it did pick up side and
back lighting in the water droplets. Also if one used the wipers it tended to
rub off causing a need for continous use of wipers.
Of course these are my own observations and I don't represent anyone, sometimes
not even myself.....
Joseph Algieri
I wonder if it has anything to do with GA aircraft having plexiglass windsreens.
Any dirt which could be ground against trhe windscreen by a wiper blade would
probably render it ruined (scratched to the point you couldn't see out of it
anymore. How about jet airliners... don't they have glass (equivalent to an
automobile winshield) windscreens?
Joe Algieri
Warrior 33673
"Because Inquiring Minds Want To Know"
Bill Standerfer
>In article <11...@orca.wv.tek.com> dono...@sptekwv1.tek.com (Donovan Hammer) writes:
>>In the Pacific NW, a pilot flys in rain 6 months out of the year. A light rain
>>simply blows off at essential any air speed that you're likely to be flying.
>
>reasonable speed), why do airliners (at least Boeing 737s) have
>windshield wipers? No prop to blast the rain away? Then what
>about twins?
In a twin, you are IMC from time you pull out of the chocks! :-) In reality,
it is a bit of a problem sometimes since it takes 20 or 30 knots to start
blowing the moisture away. Some conditions don't blow completely away,
either. When flying in clouds with no rain, the windshield often gets misty
and difficult to see through (assuming there was something to look at). Wipers
would be nice!
Also, I believe windshield wipers (or some other removal system like hot air in
the case of the Lear) are required equipment for CAT II/III certifications and
for certification of "large" airplanes (above 12,500 pounds).
Bill
Bill Standerfer -- KF0DJ -- Baron N1746W -- CFI-A
bi...@hpisla.hp.com or {...}!hplabs!hpisla!bills
Hewlett Packard Measurement Systems Operation
PO Box 301, Loveland, CO 80539 -- 303-679-2378
lan...@solvit.enet.dec.com
In article <55...@apple.Apple.COM>, c...@Apple.COM (Christopher Pettus) writes...
>
>OK, now I'm curious. If this is true (that rain blows off at any
>reasonable speed), why do airliners (at least Boeing 737s) have
>windshield wipers?
FAR part 25 - Airworthiness Standards - Transport Category Airplanes
25.1307 Miscellaneous Equipment
The following is required miscellaneous equipment:
.
.
.
(f) A windshield wiper, or equivalent, for each pilot station.
.
.
.
Really, I didn't go looking for this. I stumbled across it 'cause
a few pages of FARs were attached to a statement of work for a job
we might do for a airplane manufacturer . . .
chris
Marc Majka
happy with the result. It doesn't streak, and rain blows off
at about 40 kph. It seems to wear out after a week or two.
Of course, this wasn Vancouver B.C. I haven't had occasion
to need any in the Bay Area.
---
Marc Majka
Bill Baker
[...]
>I tried it on my car, and was less than impressed. It does make the rain
>bead up, but leaves a streaky film which is distracting at night. Consumer
>Reports recently had an article on it, where they said about the same
>thing. It probably works pretty good on an airplane, which won't have
>headlights glaring off the windscreen.
There is a certain art to applying Rain-X correctly; if you don't put it on
right it will "dry" (it seems more like it cures on glass to me) spotty or
streaky. The water will adhere along those streaks and form distracting patterns.
Dirt will stick to them, too. To avoid this, apply Rain-X like paste car wax.
Do it in strong light so you can see the patterns you're leaving. Use just
a little bit and really rub it in. For one thing, it's a great solvent; your
windows will never be cleaner. If you use too much, the Rain-X will bead
up on the glass. You should be able to see this in the way the light reflects.
Rebuff the window to spread out the liquid. Usually what happens is the first swipe
leaves beads of Rain-X and as you keep buffing and spreading it out it will form into
a dull haze on the glass. Keep going until it looks like the buffing pattern of a
good hand-waxing job. Then rinse it off with lots of warm water.
Yes, it's kind of a pain to get it right but it's worth it. I did just half of my
windshield and the difference was startling. I would normally trust Consumer Reports
on anything, but they goofed if they said headlight glare was a problem. It doesn't
leave any kind of film that you can notice. Besides, the stuff spreads *really
well*; a $4 bottle should last you years.
You only need to use it once every three months or so. More if it rains a lot, I
guess. Besides rain, the smog particulate just blows right off the window. Here in
the Valley a week of sitting outside will coat your car with smog grime. Well, my
car is often dirty but at least the windows are always clean. The only drawback is
that the right conditions can make wipers stick and skip, but that doesn't happen
very often.
If I was still living at home (Seattle) I'd never drive a car without the stuff.
The beading effect is really handy for those drizzly days; because it doesn't let
the water create a film on the window, the drizzle doesn't really obscure vision.
David E Allen
For a single-engined plane (except pushers), the fan in front adds to the
wind energy clearing the rain off. Twins more often have wipers because they
don't have help from the fan(s).
When I was a VFR (only) pilot, my rule of thumb was "If I could see through
a rainshower, I would fly through it; if not, I would go around it."
Tell me about pilot heat, though. It's a new thing to me, you see, after 25
years of flying. I seem to remember "any time in visible moisture (rain or
clouds)". So I'm popping in and out of low CU... Or it's 80 degrees out...
What do you do? Thanks.
dave allen - Fly because you love it.
lan...@solvit.enet.dec.com
In article <4566...@col.hp.com>, da...@col.hp.com (David E Allen) writes...
>
>Tell me about pilot heat, though.
Pretty simple, when I'm cold, I pull the knob out a bit!
Oh! You mean _pitot_ heat! Good question, but I don't have that
answer.
chris
Bill Standerfer
>[...]
>When I was a VFR (only) pilot, my rule of thumb was "If I could see through
>a rainshower, I would fly through it; if not, I would go around it."
>
I used to follow this rule of thumb also. However, now that I'm older (though
not necessarily wiser), I think this rule could get you into very deep
trouble. A rain shower is the signal for several possibilities:
1. At the very least, a downdraft.
2. In our dry air around here, even a light shower is a good indicator of a
downburst or microburst, to be avoided, especially at low altitudes.
3. Lightning.
4. Moderate or greater turbulence *just outside* the shower in the shear
between the updrafts and downdraft where the rain is, or associated with the
gust front. The rain shaft itself is usually quite smooth, if, that is, you
can outclimb the downdraft.
All of the above, of course, assumes thundershower weather. If it is just
widespread light rain, then you don't generally have these problems. My
opinion is to avoid *showers* by several miles for a safe ride. If the shower
(or virga!) is right over the airport you're using, give serious consideration
to staying away until it passes.
>Tell me about pilot heat, though. It's a new thing to me, you see, after 25
>years of flying. I seem to remember "any time in visible moisture (rain or
>clouds)". So I'm popping in and out of low CU... Or it's 80 degrees out...
>What do you do? Thanks.
My checklist now says "Pitot heat on in visible moisture below 8 degrees C."
I'm trying to remember exactly where I got the 8 degree number. Probably an
FAA publication somewhere.