|
|
 | | From: | Sylvia Else | | Subject: | Re: Effect of spoilers on braking | | Date: | Mon, 22 Nov 2004 09:03:10 +1100 |
|
|
 |
Rich Ahrens wrote:
> Sylvia Else wrote:
>> Wouldn't help even if it were possible (which I doubt). The
>> coefficient of friction of metal on the runway surface will be lower
>> than that of rubber, so the breaking effect would be reduced. This is
>> true regardless of the area in contact, since the greater the area,
>> the lower the pressure.
>
>
> You have just reached a colossally new peak of idiocy with that bit of
> analysis.
Added alt.sci.physics, sci.misc, aus.science.
Sylvia.
|
|
| | From: | Rich Ahrens | | Subject: | Re: Effect of spoilers on braking | | Date: | Sun, 21 Nov 2004 18:21:40 -0600 |
|
|
| Sylvia Else wrote:
>
>
> Rich Ahrens wrote:
>
>> Sylvia Else wrote:
>
>
>
>>> Wouldn't help even if it were possible (which I doubt). The
>>> coefficient of friction of metal on the runway surface will be lower
>>> than that of rubber, so the breaking effect would be reduced. This is
>>> true regardless of the area in contact, since the greater the area,
>>> the lower the pressure.
>>
>>
>>
>> You have just reached a colossally new peak of idiocy with that bit of
>> analysis.
>
>
> Added alt.sci.physics, sci.misc, aus.science.
We should expect to hear no whining about crossposting from you in the
future...
So just to continue the clarification here, you're speaking of actual
transport aircraft, not some ideal model you've cooked up in your needy
mind? Ones with bellies which will quickly shred to expose all sorts of
structure, absorbing energy and blowing your assumed coefficient of
friction to all hell? And which frequently have all kinds of dangly
bits, like engines, likely to contact the runway first with the same
effects as well as likely ground-looping the aircraft off the runway?
You're still suggesting that, taking all those realities into account, a
gear-up landing will take more distance than maximum-effort braking with
the gear down?
|
|
| | From: | AbsolutelyCertain | | Subject: | Re: Effect of spoilers on braking | | Date: | Sun, 21 Nov 2004 18:05:09 -0700 |
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|
|
"Rich Ahrens" wrote in message
news:41a13117$0$12467$a1866201@visi.com...
> Sylvia Else wrote:
>
> >
> >
> > Rich Ahrens wrote:
> >
> >> Sylvia Else wrote:
> >
> >
> >
> >>> Wouldn't help even if it were possible (which I doubt). The
> >>> coefficient of friction of metal on the runway surface will be lower
> >>> than that of rubber, so the breaking effect would be reduced. This is
> >>> true regardless of the area in contact, since the greater the area,
> >>> the lower the pressure.
> >>
> >>
> >>
> >> You have just reached a colossally new peak of idiocy with that bit of
> >> analysis.
> >
> >
> > Added alt.sci.physics, sci.misc, aus.science.
>
> We should expect to hear no whining about crossposting from you in the
> future...
>
> So just to continue the clarification here, you're speaking of actual
> transport aircraft, not some ideal model you've cooked up in your needy
> mind? Ones with bellies which will quickly shred to expose all sorts of
> structure, absorbing energy and blowing your assumed coefficient of
> friction to all hell? And which frequently have all kinds of dangly
> bits, like engines, likely to contact the runway first with the same
> effects as well as likely ground-looping the aircraft off the runway?
> You're still suggesting that, taking all those realities into account, a
> gear-up landing will take more distance than maximum-effort braking with
> the gear down?
Exactly. She made a WAG, and she will never be able to prove that she's
right, IMO. But that won't stop her from resorting to browbeating and
snidery now to cover up for the fact that she really doesn't know how far
that belly-landed airplane would slide.
This is a whole new troll tactic, and I have to admit, it's inventive. But
a troll is still a troll.
|
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| | From: | Sylvia Else | | Subject: | Re: Effect of spoilers on braking | | Date: | Mon, 22 Nov 2004 12:39:44 +1100 |
|
|
|
Rich Ahrens wrote:
> Sylvia Else wrote:
>
>>
>>
>> Rich Ahrens wrote:
>>
>>> Sylvia Else wrote:
>>
>>
>>
>>
>>>> Wouldn't help even if it were possible (which I doubt). The
>>>> coefficient of friction of metal on the runway surface will be lower
>>>> than that of rubber, so the breaking effect would be reduced. This
>>>> is true regardless of the area in contact, since the greater the
>>>> area, the lower the pressure.
>>>
>>>
>>>
>>>
>>> You have just reached a colossally new peak of idiocy with that bit
>>> of analysis.
>>
>>
>>
>> Added alt.sci.physics, sci.misc, aus.science.
>
>
> We should expect to hear no whining about crossposting from you in the
> future...
>
> So just to continue the clarification here, you're speaking of actual
> transport aircraft, not some ideal model you've cooked up in your needy
> mind? Ones with bellies which will quickly shred to expose all sorts of
> structure, absorbing energy and blowing your assumed coefficient of
> friction to all hell? And which frequently have all kinds of dangly
> bits, like engines, likely to contact the runway first with the same
> effects as well as likely ground-looping the aircraft off the runway?
> You're still suggesting that, taking all those realities into account, a
> gear-up landing will take more distance than maximum-effort braking with
> the gear down?
Yes.
Sylvia.
|
|
| | From: | dar7yl | | Subject: | Re: Effect of spoilers on braking | | Date: | Fri, 26 Nov 2004 18:14:50 GMT |
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|
|
"Sylvia Else" wrote in message
news:41A14360.80202@not.at.this.address...
>
>
> Rich Ahrens wrote:
>> You're still suggesting that, taking all those realities into account, a
>> gear-up landing will take more distance than maximum-effort braking with
>> the gear down?
>
> Yes.
Perhaps I could suggest we provide maximum braking effort by erecting a 50'
(standard FAA height) barrier at the threshold of the runway, thereby
stopping the aircraft in the minimal possible distance.
regards,
Dar7yl
|
|
| | From: | running with scissors | | Subject: | Re: Effect of spoilers on braking | | Date: | 26 Nov 2004 14:31:57 -0800 |
|
|
| "dar7yl" wrote in message news:...
> "Sylvia Else" wrote in message
> news:41A14360.80202@not.at.this.address...
> >
> >
> > Rich Ahrens wrote:
> >> You're still suggesting that, taking all those realities into account, a
> >> gear-up landing will take more distance than maximum-effort braking with
> >> the gear down?
> >
> > Yes.
>
> Perhaps I could suggest we provide maximum braking effort by erecting a 50'
> (standard FAA height) barrier at the threshold of the runway, thereby
> stopping the aircraft in the minimal possible distance.
>
> regards,
> Dar7yl
quite brilliant!
|
|
| | From: | Sylvia Else | | Subject: | Re: Effect of spoilers on braking | | Date: | Mon, 22 Nov 2004 13:09:51 +1100 |
|
|
|
Sylvia Else wrote:
>
>
> Rich Ahrens wrote:
>
>> Sylvia Else wrote:
>>
>>>
>>>
>>> Rich Ahrens wrote:
>>>
>>>> Sylvia Else wrote:
>>>
>>>
>>>
>>>
>>>
>>>>> Wouldn't help even if it were possible (which I doubt). The
>>>>> coefficient of friction of metal on the runway surface will be
>>>>> lower than that of rubber, so the breaking effect would be reduced.
>>>>> This is true regardless of the area in contact, since the greater
>>>>> the area, the lower the pressure.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> You have just reached a colossally new peak of idiocy with that bit
>>>> of analysis.
>>>
>>>
>>>
>>>
>>> Added alt.sci.physics, sci.misc, aus.science.
>>
>>
>>
>> We should expect to hear no whining about crossposting from you in the
>> future...
>>
>> So just to continue the clarification here, you're speaking of actual
>> transport aircraft, not some ideal model you've cooked up in your
>> needy mind? Ones with bellies which will quickly shred to expose all
>> sorts of structure, absorbing energy and blowing your assumed
>> coefficient of friction to all hell? And which frequently have all
>> kinds of dangly bits, like engines, likely to contact the runway first
>> with the same effects as well as likely ground-looping the aircraft
>> off the runway? You're still suggesting that, taking all those
>> realities into account, a gear-up landing will take more distance than
>> maximum-effort braking with the gear down?
>
>
> Yes.
>
> Sylvia.
>
>
As an example of a wheels up landing (in a DC9), consider
http://www.ntsb.gov/publictn/1997/AAR9701.pdf
The preamble describes the event thus:
"On February 19, 1996, at 0902 central standard time, Continental
Airlines (COA) flight 1943, a Douglas DC-9-32, N10556, landed wheels up
on runway 27 at the Houston Intercontinental Airport, Houston, Texas.
The airplane slid 6,850 feet before coming to rest in the grass about
140 feet left of the runway centerline."
Sylvia.
|
|
| | From: | AbsolutelyCertain | | Subject: | Re: Effect of spoilers on braking | | Date: | Sun, 21 Nov 2004 15:18:08 -0700 |
|
|
|
"Sylvia Else" wrote in message
news:41A1109E.7010409@not.at.this.address...
>
>
> Rich Ahrens wrote:
>
> > Sylvia Else wrote:
>
>
> >> Wouldn't help even if it were possible (which I doubt). The
> >> coefficient of friction of metal on the runway surface will be lower
> >> than that of rubber, so the breaking effect would be reduced. This is
> >> true regardless of the area in contact, since the greater the area,
> >> the lower the pressure.
> >
> >
> > You have just reached a colossally new peak of idiocy with that bit of
> > analysis.
>
> Added alt.sci.physics, sci.misc, aus.science.
Well, I think if you're right, then heavy and complicated landing gear just
became unnecessary. Simply lengthen runways, and put skid plates on the
bottoms of airplanes. With that low coefficient of friction, little damage
will be done, and reverse thrust can do the bulk of the work. After
stopping, just slide some ground-bound wheels under the thing and taxi it
away. Thousands of pounds of weight saved. Didn't I see something like
that on the cover of Popular Science Magazine circa 1953? The
Slide-o-Cruiser?
|
|
| | From: | Ralph Nesbitt | | Subject: | Re: Effect of spoilers on braking | | Date: | Wed, 01 Dec 2004 06:24:44 GMT |
|
|
|
"AbsolutelyCertain" wrote in message
news:cnr474$nea$0@pita.alt.net...
>
> "Sylvia Else" wrote in message
> news:41A1109E.7010409@not.at.this.address...
> >
> >
> > Rich Ahrens wrote:
> >
> > > Sylvia Else wrote:
> >
> >
> > >> Wouldn't help even if it were possible (which I doubt). The
> > >> coefficient of friction of metal on the runway surface will be lower
> > >> than that of rubber, so the breaking effect would be reduced. This is
> > >> true regardless of the area in contact, since the greater the area,
> > >> the lower the pressure.
> > >
> > >
> > > You have just reached a colossally new peak of idiocy with that bit of
> > > analysis.
> >
> > Added alt.sci.physics, sci.misc, aus.science.
>
> Well, I think if you're right, then heavy and complicated landing gear
just
> became unnecessary. Simply lengthen runways, and put skid plates on the
> bottoms of airplanes. With that low coefficient of friction, little
damage
> will be done, and reverse thrust can do the bulk of the work. After
> stopping, just slide some ground-bound wheels under the thing and taxi it
> away. Thousands of pounds of weight saved. Didn't I see something like
> that on the cover of Popular Science Magazine circa 1953? The
> Slide-o-Cruiser?
>
SOLO, Indonesia (Reuters 11/30/04) - Rescue teams searched areas around a
central Indonesia airport Wednesday for survivors and victims of a plane
crash that police said killed at least 31 people and left 47 unaccounted
for.
The McDonnell-Douglas MD-82, operated by budget domestic carrier Lion Air
and carrying 163 passengers and crew, skidded off the runway of Solo city's
airport as it landed in heavy rain around dusk Tuesday after a flight from
Jakarta.
Other sources were giving different numbers. A Lion Air official said only
154 people -- 146 passengers and eight crew -- were aboard, of whom 25 were
known dead.
This one over ran the Ry into a grave yard according to the news story. This
gives a whole new meaning to the classic statement "Tomb Stone Safety". For
the full story see: http://makeashorterlink.com/?H5A2219E9
Ralph Nesbitt
Professional FD/CFR/ARFF Type
Posting From ADA
|
|
| | From: | running with scissors | | Subject: | Re: Effect of spoilers on braking | | Date: | 1 Dec 2004 17:03:34 -0800 |
|
|
| "Ralph Nesbitt" wrote in message news:...
> "AbsolutelyCertain" wrote in message
> news:cnr474$nea$0@pita.alt.net...
> >
> > "Sylvia Else" wrote in message
> > news:41A1109E.7010409@not.at.this.address...
> > >
> > >
> > > Rich Ahrens wrote:
> > >
> > > > Sylvia Else wrote:
> > >
> > >
> > > >> Wouldn't help even if it were possible (which I doubt). The
> > > >> coefficient of friction of metal on the runway surface will be lower
> > > >> than that of rubber, so the breaking effect would be reduced. This is
> > > >> true regardless of the area in contact, since the greater the area,
> > > >> the lower the pressure.
> > > >
> > > >
> > > > You have just reached a colossally new peak of idiocy with that bit of
> > > > analysis.
> > >
> > > Added alt.sci.physics, sci.misc, aus.science.
> >
> > Well, I think if you're right, then heavy and complicated landing gear
> just
> > became unnecessary. Simply lengthen runways, and put skid plates on the
> > bottoms of airplanes. With that low coefficient of friction, little
> damage
> > will be done, and reverse thrust can do the bulk of the work. After
> > stopping, just slide some ground-bound wheels under the thing and taxi it
> > away. Thousands of pounds of weight saved. Didn't I see something like
> > that on the cover of Popular Science Magazine circa 1953? The
> > Slide-o-Cruiser?
> >
> SOLO, Indonesia (Reuters 11/30/04) - Rescue teams searched areas around a
> central Indonesia airport Wednesday for survivors and victims of a plane
> crash that police said killed at least 31 people and left 47 unaccounted
> for.
>
> The McDonnell-Douglas MD-82, operated by budget domestic carrier Lion Air
> and carrying 163 passengers and crew, skidded off the runway of Solo city's
> airport as it landed in heavy rain around dusk Tuesday after a flight from
> Jakarta.
>
>
> Other sources were giving different numbers. A Lion Air official said only
> 154 people -- 146 passengers and eight crew -- were aboard, of whom 25 were
> known dead.
>
> This one over ran the Ry into a grave yard according to the news story. This
> gives a whole new meaning to the classic statement "Tomb Stone Safety". For
> the full story see: http://makeashorterlink.com/?H5A2219E9
> Ralph Nesbitt
> Professional FD/CFR/ARFF Type
> Posting From ADA
disparity in the body count & overrun location noted...
.... how deep are they digging for bodies ??
|
|
| | From: | Ralph Nesbitt | | Subject: | Re: Effect of spoilers on braking | | Date: | Fri, 03 Dec 2004 18:22:57 GMT |
|
|
|
"running with scissors" wrote in
message news:d0fe9d08.0412011703.dcd580c@posting.google.com...
> "Ralph Nesbitt" wrote in message
news:...
> > "AbsolutelyCertain" wrote in message
> > news:cnr474$nea$0@pita.alt.net...
> > >
> > > "Sylvia Else" wrote in message
> > > news:41A1109E.7010409@not.at.this.address...
> > > >
> > > >
> > > > Rich Ahrens wrote:
> > > >
> > > > > Sylvia Else wrote:
> > > >
> > > >
> > > > >> Wouldn't help even if it were possible (which I doubt). The
> > > > >> coefficient of friction of metal on the runway surface will be
lower
> > > > >> than that of rubber, so the breaking effect would be reduced.
This is
> > > > >> true regardless of the area in contact, since the greater the
area,
> > > > >> the lower the pressure.
> > > > >
> > > > >
> > > > > You have just reached a colossally new peak of idiocy with that
bit of
> > > > > analysis.
> > > >
> > > > Added alt.sci.physics, sci.misc, aus.science.
> > >
> > > Well, I think if you're right, then heavy and complicated landing gear
> > just
> > > became unnecessary. Simply lengthen runways, and put skid plates on
the
> > > bottoms of airplanes. With that low coefficient of friction, little
> > damage
> > > will be done, and reverse thrust can do the bulk of the work. After
> > > stopping, just slide some ground-bound wheels under the thing and taxi
it
> > > away. Thousands of pounds of weight saved. Didn't I see something
like
> > > that on the cover of Popular Science Magazine circa 1953? The
> > > Slide-o-Cruiser?
> > >
> > SOLO, Indonesia (Reuters 11/30/04) - Rescue teams searched areas around
a
> > central Indonesia airport Wednesday for survivors and victims of a plane
> > crash that police said killed at least 31 people and left 47 unaccounted
> > for.
> >
> > The McDonnell-Douglas MD-82, operated by budget domestic carrier Lion
Air
> > and carrying 163 passengers and crew, skidded off the runway of Solo
city's
> > airport as it landed in heavy rain around dusk Tuesday after a flight
from
> > Jakarta.
> >
> >
> > Other sources were giving different numbers. A Lion Air official said
only
> > 154 people -- 146 passengers and eight crew -- were aboard, of whom 25
were
> > known dead.
> >
> > This one over ran the Ry into a grave yard according to the news story.
This
> > gives a whole new meaning to the classic statement "Tomb Stone Safety".
For
> > the full story see: http://makeashorterlink.com/?H5A2219E9
> > Ralph Nesbitt
> > Professional FD/CFR/ARFF Type
> > Posting From ADA
>
> disparity in the body count & overrun location noted...
> ... how deep are they digging for bodies ??
>
A good question. Heard the joke re a Polish A/C crashing into a grave yard &
they were still recovering bodies several months later.
Seriously, this is the first major A/C incident I have heard of where the
A/C came to rest in a grave Yard.
Ralph Nesbitt
Professional FD/CFR/ARFF Type
Posting From ADA
|
|
| | From: | Sylvia Else | | Subject: | Re: Effect of spoilers on braking | | Date: | Mon, 22 Nov 2004 09:29:09 +1100 |
|
|
|
AbsolutelyCertain wrote:
> "Sylvia Else" wrote in message
> news:41A1109E.7010409@not.at.this.address...
>
>>
>>Rich Ahrens wrote:
>>
>>
>>>Sylvia Else wrote:
>>
>>
>>>>Wouldn't help even if it were possible (which I doubt). The
>>>>coefficient of friction of metal on the runway surface will be lower
>>>>than that of rubber, so the breaking effect would be reduced. This is
>>>>true regardless of the area in contact, since the greater the area,
>>>>the lower the pressure.
>>>
>>>
>>>You have just reached a colossally new peak of idiocy with that bit of
>>>analysis.
>>
>>Added alt.sci.physics, sci.misc, aus.science.
>
>
> Well, I think if you're right, then heavy and complicated landing gear just
> became unnecessary. Simply lengthen runways, and put skid plates on the
> bottoms of airplanes. With that low coefficient of friction, little damage
> will be done, and reverse thrust can do the bulk of the work. After
> stopping, just slide some ground-bound wheels under the thing and taxi it
> away. Thousands of pounds of weight saved. Didn't I see something like
> that on the cover of Popular Science Magazine circa 1953? The
> Slide-o-Cruiser?
>
You're not meant to run reverse thrust at low IAS. Also there would be
little directional control, runways would cost more, runway occupancy
times would increase, to name but three other objections that come
immediately to mind.
Sylvia.
|
|
| | From: | JL Grasso | | Subject: | Re: Effect of spoilers on braking | | Date: | Sun, 21 Nov 2004 20:40:31 -0600 |
|
|
| On Mon, 22 Nov 2004 09:29:09 +1100, Sylvia Else
wrote:
>You're not meant to run reverse thrust at low IAS.
And why is that?
Jerry
|
|
| | From: | Sylvia Else | | Subject: | Re: Effect of spoilers on braking | | Date: | Mon, 22 Nov 2004 14:56:44 +1100 |
|
|
|
JL Grasso wrote:
> On Mon, 22 Nov 2004 09:29:09 +1100, Sylvia Else
> wrote:
>
>
>>You're not meant to run reverse thrust at low IAS.
>
>
> And why is that?
>
> Jerry
>
Creates turbulent flow at the engine inlets. Not a good look if you want
your engines to last.
Sylvia.
|
|
| | From: | Bertie the Bunyip | | Subject: | Re: Effect of spoilers on braking | | Date: | Thu, 25 Nov 2004 05:50:01 +0000 (UTC) |
|
|
| Sylvia Else
sednews:41A1637C.70304@not.at.this.address:
>
>
> JL Grasso wrote:
>> On Mon, 22 Nov 2004 09:29:09 +1100, Sylvia Else
>> wrote:
>>
>>
>>>You're not meant to run reverse thrust at low IAS.
>>
>>
>> And why is that?
>>
>> Jerry
>>
>
> Creates turbulent flow at the engine inlets. Not a good look if you want
> your engines to last.
>
Bullshit.
Bertie
|
|
| | From: | JL Grasso | | Subject: | Re: Effect of spoilers on braking | | Date: | Sun, 21 Nov 2004 22:02:18 -0600 |
|
|
| On Mon, 22 Nov 2004 14:56:44 +1100, Sylvia Else
wrote:
>
>
>JL Grasso wrote:
>> On Mon, 22 Nov 2004 09:29:09 +1100, Sylvia Else
>> wrote:
>>
>>
>>>You're not meant to run reverse thrust at low IAS.
>>
>>
>> And why is that?
>>
>> Jerry
>>
>
>Creates turbulent flow at the engine inlets. Not a good look if you want
> your engines to last.
Maybe on some installations. A lot of aircraft use them while taxiing to
avoid riding the brakes. Maybe you should tell them your theory!
Jerry
|
|
| | From: | Bertie the Bunyip | | Subject: | Re: Effect of spoilers on braking | | Date: | Thu, 25 Nov 2004 05:51:30 +0000 (UTC) |
|
|
| JL Grasso sednews:10q2p6b57vpbu91@news.supernews.com:
> On Mon, 22 Nov 2004 14:56:44 +1100, Sylvia Else
> wrote:
>
>>
>>
>>JL Grasso wrote:
>>> On Mon, 22 Nov 2004 09:29:09 +1100, Sylvia Else
>>> wrote:
>>>
>>>
>>>>You're not meant to run reverse thrust at low IAS.
>>>
>>>
>>> And why is that?
>>>
>>> Jerry
>>>
>>
>>Creates turbulent flow at the engine inlets. Not a good look if you want
>> your engines to last.
>
> Maybe on some installations. A lot of aircraft use them while taxiing to
> avoid riding the brakes. Maybe you should tell them your theory!
>
not to mantion being aboel to actually reverse the aircraft..
Bertie
|
|
| | From: | dar7yl | | Subject: | Re: Effect of spoilers on braking | | Date: | Fri, 26 Nov 2004 18:09:14 GMT |
|
|
|
"JL Grasso" wrote in message
news:10q2kd0nij2ua2@news.supernews.com...
> On Mon, 22 Nov 2004 09:29:09 +1100, Sylvia Else
> wrote:
>
>>You're not meant to run reverse thrust at low IAS.
>
> And why is that?
Because that is the surest way of crashing the aircraft and killing
yourself.
Perhaps, the author meant to say "You're not meant to run reverse thrust
when the plane is not on the ground"
At low IAS (Indicated Air Speed), the wing is on the verge of stalling. Any
reduction in forward speed, for instance by engaging reverse thrust (Beta)
while the plane is still in the air, could precipitate the stall, and auger
that plane in.
Once the wheels have hit the pavement, the wing is no longer required to
keep the airplane flying, and beta can be used. During the first few
seconds after touchdown, beta is the major source of deceleration, along
with aerodynamic drag. The brakes gradually become more effective as the
wing sheds it's lift and the normal braking forces increase. Beta gradually
becomes less effective as the engines' inlet air supply is reduced.
regards,
Dar7yl
|
|
| | From: | AbsolutelyCertain | | Subject: | Re: Effect of spoilers on braking | | Date: | Sun, 21 Nov 2004 15:36:20 -0700 |
|
|
|
"Sylvia Else" wrote in message
news:41A116B5.2070101@not.at.this.address...
>
>
> AbsolutelyCertain wrote:
> > "Sylvia Else" wrote in message
> > news:41A1109E.7010409@not.at.this.address...
> >
> >>
> >>Rich Ahrens wrote:
> >>
> >>
> >>>Sylvia Else wrote:
> >>
> >>
> >>>>Wouldn't help even if it were possible (which I doubt). The
> >>>>coefficient of friction of metal on the runway surface will be lower
> >>>>than that of rubber, so the breaking effect would be reduced. This is
> >>>>true regardless of the area in contact, since the greater the area,
> >>>>the lower the pressure.
> >>>
> >>>
> >>>You have just reached a colossally new peak of idiocy with that bit of
> >>>analysis.
> >>
> >>Added alt.sci.physics, sci.misc, aus.science.
> >
> >
> > Well, I think if you're right, then heavy and complicated landing gear
just
> > became unnecessary. Simply lengthen runways, and put skid plates on the
> > bottoms of airplanes. With that low coefficient of friction, little
damage
> > will be done, and reverse thrust can do the bulk of the work. After
> > stopping, just slide some ground-bound wheels under the thing and taxi
it
> > away. Thousands of pounds of weight saved. Didn't I see something like
> > that on the cover of Popular Science Magazine circa 1953? The
> > Slide-o-Cruiser?
> >
>
> You're not meant to run reverse thrust at low IAS. Also there would be
> little directional control, runways would cost more, runway occupancy
> times would increase, to name but three other objections that come
> immediately to mind.
Yes, yes. So, let me see if I have this right. Two identical and
identically loaded and flown MD-80s land on parallel identical runways which
I presume, a thunderstorm having been in the area, are wet. One airplane
lands wheels up, and other wheels down, and you can prove that the
wheels-down airplane will stop first? Nothing other than braking or
airplane-to-ground friction will provide what you call "stopping power".
Can we see the work on that, please?
|
|
| | From: | Sylvia Else | | Subject: | Re: Effect of spoilers on braking | | Date: | Mon, 22 Nov 2004 10:16:58 +1100 |
|
|
|
AbsolutelyCertain wrote:
> "Sylvia Else" wrote in message
> news:41A116B5.2070101@not.at.this.address...
>
>>
>>AbsolutelyCertain wrote:
>>
>>>"Sylvia Else" wrote in message
>>>news:41A1109E.7010409@not.at.this.address...
>>>
>>>
>>>>Rich Ahrens wrote:
>>>>
>>>>
>>>>
>>>>>Sylvia Else wrote:
>>>>
>>>>
>>>>>>Wouldn't help even if it were possible (which I doubt). The
>>>>>>coefficient of friction of metal on the runway surface will be lower
>>>>>>than that of rubber, so the breaking effect would be reduced. This is
>>>>>>true regardless of the area in contact, since the greater the area,
>>>>>>the lower the pressure.
>>>>>
>>>>>
>>>>>You have just reached a colossally new peak of idiocy with that bit of
>>>>>analysis.
>>>>
>>>>Added alt.sci.physics, sci.misc, aus.science.
>>>
>>>
>>>Well, I think if you're right, then heavy and complicated landing gear
>>
> just
>
>>>became unnecessary. Simply lengthen runways, and put skid plates on the
>>>bottoms of airplanes. With that low coefficient of friction, little
>>
> damage
>
>>>will be done, and reverse thrust can do the bulk of the work. After
>>>stopping, just slide some ground-bound wheels under the thing and taxi
>>
> it
>
>>>away. Thousands of pounds of weight saved. Didn't I see something like
>>>that on the cover of Popular Science Magazine circa 1953? The
>>>Slide-o-Cruiser?
>>>
>>
>>You're not meant to run reverse thrust at low IAS. Also there would be
>>little directional control, runways would cost more, runway occupancy
>>times would increase, to name but three other objections that come
>>immediately to mind.
>
>
> Yes, yes. So, let me see if I have this right. Two identical and
> identically loaded and flown MD-80s land on parallel identical runways which
> I presume, a thunderstorm having been in the area, are wet. One airplane
> lands wheels up, and other wheels down, and you can prove that the
> wheels-down airplane will stop first? Nothing other than braking or
> airplane-to-ground friction will provide what you call "stopping power".
>
> Can we see the work on that, please?
>
I seem to be a bit short of spare MD-80s right now for doing the
experiments, and the local airline (which initially was quite
interested) demurred when I mentioned the gear up aspect. However, the
underlying principle is quite easy to demonstrate.
Wrap a CD in kitchen foil - it will weigh about 20 grams. Get a rubber
pencil eraser of about the same weight. Place both on a suitable flat
surface, and start tilting the surface. The one that has the lower
frictional force on it will move first.
So which one is it? The metal covered large area CD, or the rubber small
area pencil eraser?
If you think the answer is the small area pencil eraser, then you're in
for a surprise.
Sylvia.
|
|
| | From: | Ralph Nesbitt | | Subject: | Re: Effect of spoilers on braking | | Date: | Wed, 01 Dec 2004 16:39:08 GMT |
|
|
|
"Sylvia Else" wrote in message
news:41A121EA.1090700@not.at.this.address...
>
>
> AbsolutelyCertain wrote:
> > "Sylvia Else" wrote in message
> > news:41A116B5.2070101@not.at.this.address...
> >
> >>
> >>AbsolutelyCertain wrote:
> >>
> >>>"Sylvia Else" wrote in message
> >>>news:41A1109E.7010409@not.at.this.address...
> >>>
> >>>
> >>>>Rich Ahrens wrote:
> >>>>
> >>>>
> >>>>
> >>>>>Sylvia Else wrote:
> >>>>
> >>>>
> >>>>>>Wouldn't help even if it were possible (which I doubt). The
> >>>>>>coefficient of friction of metal on the runway surface will be lower
> >>>>>>than that of rubber, so the breaking effect would be reduced. This
is
> >>>>>>true regardless of the area in contact, since the greater the area,
> >>>>>>the lower the pressure.
> >>>>>
> >>>>>
> >>>>>You have just reached a colossally new peak of idiocy with that bit
of
> >>>>>analysis.
> >>>>
> >>>>Added alt.sci.physics, sci.misc, aus.science.
> >>>
> >>>
> >>>Well, I think if you're right, then heavy and complicated landing gear
> >>
> > just
> >
> >>>became unnecessary. Simply lengthen runways, and put skid plates on
the
> >>>bottoms of airplanes. With that low coefficient of friction, little
> >>
> > damage
> >
> >>>will be done, and reverse thrust can do the bulk of the work. After
> >>>stopping, just slide some ground-bound wheels under the thing and taxi
> >>
> > it
> >
> >>>away. Thousands of pounds of weight saved. Didn't I see something
like
> >>>that on the cover of Popular Science Magazine circa 1953? The
> >>>Slide-o-Cruiser?
> >>>
> >>
> >>You're not meant to run reverse thrust at low IAS. Also there would be
> >>little directional control, runways would cost more, runway occupancy
> >>times would increase, to name but three other objections that come
> >>immediately to mind.
> >
> >
> > Yes, yes. So, let me see if I have this right. Two identical and
> > identically loaded and flown MD-80s land on parallel identical runways
which
> > I presume, a thunderstorm having been in the area, are wet. One
airplane
> > lands wheels up, and other wheels down, and you can prove that the
> > wheels-down airplane will stop first? Nothing other than braking or
> > airplane-to-ground friction will provide what you call "stopping power".
> >
> > Can we see the work on that, please?
> >
>
> I seem to be a bit short of spare MD-80s right now for doing the
> experiments, and the local airline (which initially was quite
> interested) demurred when I mentioned the gear up aspect. However, the
> underlying principle is quite easy to demonstrate.
>
> Wrap a CD in kitchen foil - it will weigh about 20 grams. Get a rubber
> pencil eraser of about the same weight. Place both on a suitable flat
> surface, and start tilting the surface. The one that has the lower
> frictional force on it will move first.
>
> So which one is it? The metal covered large area CD, or the rubber small
> area pencil eraser?
>
> If you think the answer is the small area pencil eraser, then you're in
> for a surprise.
>
> Sylvia.
>
I disagree with the format of your demonstration. Assume each A/C is doing
140 kts @ touch down. For your demonstration to be realistic would require
weight, surface area, & speed to be scaled appropriately to simulate touch
down & roll out/slide out.
You have also missed a basic law of physics: A mass at rest will remain at
rest unless enough force is applied to move it. Also a mass in motion will
remain in motion until it's inertia is expended.
Your proposed demonstration is not applicable to the circumstances IMHO.
Ralph Nesbitt
Professional FD/CFR/ARFF Type
Posting From ADA
|
|
| | From: | Sylvia Else | | Subject: | Re: Effect of spoilers on braking | | Date: | Thu, 02 Dec 2004 07:43:56 +1100 |
|
|
|
Ralph Nesbitt wrote:
> "Sylvia Else" wrote in message
> news:41A121EA.1090700@not.at.this.address...
>
>>
>>AbsolutelyCertain wrote:
>>
>>>"Sylvia Else" wrote in message
>>>news:41A116B5.2070101@not.at.this.address...
>>>
>>>
>>>>AbsolutelyCertain wrote:
>>>>
>>>>
>>>>>"Sylvia Else" wrote in message
>>>>>news:41A1109E.7010409@not.at.this.address...
>>>>>
>>>>>
>>>>>
>>>>>>Rich Ahrens wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>>Sylvia Else wrote:
>>>>>>
>>>>>>
>>>>>>>>Wouldn't help even if it were possible (which I doubt). The
>>>>>>>>coefficient of friction of metal on the runway surface will be lower
>>>>>>>>than that of rubber, so the breaking effect would be reduced. This
>>>>>>>
> is
>
>>>>>>>>true regardless of the area in contact, since the greater the area,
>>>>>>>>the lower the pressure.
>>>>>>>
>>>>>>>
>>>>>>>You have just reached a colossally new peak of idiocy with that bit
>>>>>>
> of
>
>>>>>>>analysis.
>>>>>>
>>>>>>Added alt.sci.physics, sci.misc, aus.science.
>>>>>
>>>>>
>>>>>Well, I think if you're right, then heavy and complicated landing gear
>>>>
>>>just
>>>
>>>
>>>>>became unnecessary. Simply lengthen runways, and put skid plates on
>>>>
> the
>
>>>>>bottoms of airplanes. With that low coefficient of friction, little
>>>>
>>>damage
>>>
>>>
>>>>>will be done, and reverse thrust can do the bulk of the work. After
>>>>>stopping, just slide some ground-bound wheels under the thing and taxi
>>>>
>>>it
>>>
>>>
>>>>>away. Thousands of pounds of weight saved. Didn't I see something
>>>>
> like
>
>>>>>that on the cover of Popular Science Magazine circa 1953? The
>>>>>Slide-o-Cruiser?
>>>>>
>>>>
>>>>You're not meant to run reverse thrust at low IAS. Also there would be
>>>>little directional control, runways would cost more, runway occupancy
>>>>times would increase, to name but three other objections that come
>>>>immediately to mind.
>>>
>>>
>>>Yes, yes. So, let me see if I have this right. Two identical and
>>>identically loaded and flown MD-80s land on parallel identical runways
>>
> which
>
>>>I presume, a thunderstorm having been in the area, are wet. One
>>
> airplane
>
>>>lands wheels up, and other wheels down, and you can prove that the
>>>wheels-down airplane will stop first? Nothing other than braking or
>>>airplane-to-ground friction will provide what you call "stopping power".
>>>
>>>Can we see the work on that, please?
>>>
>>
>>I seem to be a bit short of spare MD-80s right now for doing the
>>experiments, and the local airline (which initially was quite
>>interested) demurred when I mentioned the gear up aspect. However, the
>>underlying principle is quite easy to demonstrate.
>>
>>Wrap a CD in kitchen foil - it will weigh about 20 grams. Get a rubber
>>pencil eraser of about the same weight. Place both on a suitable flat
>>surface, and start tilting the surface. The one that has the lower
>>frictional force on it will move first.
>>
>>So which one is it? The metal covered large area CD, or the rubber small
>>area pencil eraser?
>>
>>If you think the answer is the small area pencil eraser, then you're in
>>for a surprise.
>>
>>Sylvia.
>>
>
> I disagree with the format of your demonstration. Assume each A/C is doing
> 140 kts @ touch down. For your demonstration to be realistic would require
> weight, surface area, & speed to be scaled appropriately to simulate touch
> down & roll out/slide out.
>
> You have also missed a basic law of physics: A mass at rest will remain at
> rest unless enough force is applied to move it. Also a mass in motion will
> remain in motion until it's inertia is expended.
>
> Your proposed demonstration is not applicable to the circumstances IMHO.
> Ralph Nesbitt
> Professional FD/CFR/ARFF Type
> Posting From ADA
>
Snipped alt.disasters.aviation - which may be the only place that Ralph
will see this, but I have a current policy of not posting to
alt.disasters.aviation.
Strictly speaking it is true that my demonstration is not representative
because it compares the the static friction of the two substances, where
as in the aircraft scenario, the static friction of rubber should be
compared with the sliding friction of metal. However, the static
friction can never be less than the sliding friction, so if the
demonstration shows that the static friction of metal is less than that
of rubber, then the sliding friction of metal must certainly be less
than the static friction of rubber.
In addition, it's unlikely that anyone has a spare piece of runway
surface that they can readily tilt.
As for the basic laws of physics, I don't recognise those formulations.
Sylvia.
|
|
| | From: | Bertie the Bunyip | | Subject: | Re: Effect of spoilers on braking | | Date: | Thu, 2 Dec 2004 04:52:04 +0000 (UTC) |
|
|
| Sylvia Else
sednews:41AE2D0C.9010606@not.at.this.address:
>
>
> Ralph Nesbitt wrote:
>> "Sylvia Else" wrote in message
>> news:41A121EA.1090700@not.at.this.address...
>>
>>>
>>>AbsolutelyCertain wrote:
>>>
>>>>"Sylvia Else" wrote in message
>>>>news:41A116B5.2070101@not.at.this.address...
>>>>
>>>>
>>>>>AbsolutelyCertain wrote:
>>>>>
>>>>>
>>>>>>"Sylvia Else" wrote in message
>>>>>>news:41A1109E.7010409@not.at.this.address...
>>>>>>
>>>>>>
>>>>>>
>>>>>>>Rich Ahrens wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>>Sylvia Else wrote:
>>>>>>>
>>>>>>>
>>>>>>>>>Wouldn't help even if it were possible (which I doubt). The
>>>>>>>>>coefficient of friction of metal on the runway surface will be
>>>>>>>>>lower than that of rubber, so the breaking effect would be
>>>>>>>>>reduced. This
>>>>>>>>
>> is
>>
>>>>>>>>>true regardless of the area in contact, since the greater the
>>>>>>>>>area, the lower the pressure.
>>>>>>>>
>>>>>>>>
>>>>>>>>You have just reached a colossally new peak of idiocy with that
>>>>>>>>bit
>>>>>>>
>> of
>>
>>>>>>>>analysis.
>>>>>>>
>>>>>>>Added alt.sci.physics, sci.misc, aus.science.
>>>>>>
>>>>>>
>>>>>>Well, I think if you're right, then heavy and complicated landing
>>>>>>gear
>>>>>
>>>>just
>>>>
>>>>
>>>>>>became unnecessary. Simply lengthen runways, and put skid plates
>>>>>>on
>>>>>
>> the
>>
>>>>>>bottoms of airplanes. With that low coefficient of friction,
>>>>>>little
>>>>>
>>>>damage
>>>>
>>>>
>>>>>>will be done, and reverse thrust can do the bulk of the work.
>>>>>>After stopping, just slide some ground-bound wheels under the
>>>>>>thing and taxi
>>>>>
>>>>it
>>>>
>>>>
>>>>>>away. Thousands of pounds of weight saved. Didn't I see
>>>>>>something
>>>>>
>> like
>>
>>>>>>that on the cover of Popular Science Magazine circa 1953? The
>>>>>>Slide-o-Cruiser?
>>>>>>
>>>>>
>>>>>You're not meant to run reverse thrust at low IAS. Also there would
>>>>>be little directional control, runways would cost more, runway
>>>>>occupancy times would increase, to name but three other objections
>>>>>that come immediately to mind.
>>>>
>>>>
>>>>Yes, yes. So, let me see if I have this right. Two identical and
>>>>identically loaded and flown MD-80s land on parallel identical
>>>>runways
>>>
>> which
>>
>>>>I presume, a thunderstorm having been in the area, are wet. One
>>>
>> airplane
>>
>>>>lands wheels up, and other wheels down, and you can prove that the
>>>>wheels-down airplane will stop first? Nothing other than braking or
>>>>airplane-to-ground friction will provide what you call "stopping
>>>>power".
>>>>
>>>>Can we see the work on that, please?
>>>>
>>>
>>>I seem to be a bit short of spare MD-80s right now for doing the
>>>experiments, and the local airline (which initially was quite
>>>interested) demurred when I mentioned the gear up aspect. However,
>>>the underlying principle is quite easy to demonstrate.
>>>
>>>Wrap a CD in kitchen foil - it will weigh about 20 grams. Get a
>>>rubber pencil eraser of about the same weight. Place both on a
>>>suitable flat surface, and start tilting the surface. The one that
>>>has the lower frictional force on it will move first.
>>>
>>>So which one is it? The metal covered large area CD, or the rubber
>>>small area pencil eraser?
>>>
>>>If you think the answer is the small area pencil eraser, then you're
>>>in for a surprise.
>>>
>>>Sylvia.
>>>
>>
>> I disagree with the format of your demonstration. Assume each A/C is
>> doing 140 kts @ touch down. For your demonstration to be realistic
>> would require weight, surface area, & speed to be scaled
>> appropriately to simulate touch down & roll out/slide out.
>>
>> You have also missed a basic law of physics: A mass at rest will
>> remain at rest unless enough force is applied to move it. Also a mass
>> in motion will remain in motion until it's inertia is expended.
>>
>> Your proposed demonstration is not applicable to the circumstances
>> IMHO. Ralph Nesbitt
>> Professional FD/CFR/ARFF Type
>> Posting From ADA
>>
>
> Snipped alt.disasters.aviation - which may be the only place that
> Ralph will see this, but I have a current policy of not posting to
> alt.disasters.aviation.
I'm sure Ralph will be devastated.
>
> As for the basic laws of physics, I don't recognise those
> formulations.
Yes, we can see that.
|
|
| | From: | running with scissors | | Subject: | Re: Effect of spoilers on braking | | Date: | 2 Dec 2004 20:15:09 -0800 |
|
|
| Sylvia Else wrote in message news:<41AE2D0C.9010606@not.at.this.address>...
> >
>
> Snipped alt.disasters.aviation - which may be the only place that Ralph
> will see this, but I have a current policy of not posting to
> alt.disasters.aviation.
a policy huh! enacted by whom ? your minister of defense?
|
|
| | From: | AbsolutelyCertain | | Subject: | Re: Effect of spoilers on braking | | Date: | Sun, 21 Nov 2004 16:41:32 -0700 |
|
|
|
"Sylvia Else" wrote in message
news:41A121EA.1090700@not.at.this.address...
>
>
> AbsolutelyCertain wrote:
> > "Sylvia Else" wrote in message
> > news:41A116B5.2070101@not.at.this.address...
> >
> >>
> >>AbsolutelyCertain wrote:
> >>
> >>>"Sylvia Else" wrote in message
> >>>news:41A1109E.7010409@not.at.this.address...
> >>>
> >>>
> >>>>Rich Ahrens wrote:
> >>>>
> >>>>
> >>>>
> >>>>>Sylvia Else wrote:
> >>>>
> >>>>
> >>>>>>Wouldn't help even if it were possible (which I doubt). The
> >>>>>>coefficient of friction of metal on the runway surface will be lower
> >>>>>>than that of rubber, so the breaking effect would be reduced. This
is
> >>>>>>true regardless of the area in contact, since the greater the area,
> >>>>>>the lower the pressure.
> >>>>>
> >>>>>
> >>>>>You have just reached a colossally new peak of idiocy with that bit
of
> >>>>>analysis.
> >>>>
> >>>>Added alt.sci.physics, sci.misc, aus.science.
> >>>
> >>>
> >>>Well, I think if you're right, then heavy and complicated landing gear
> >>
> > just
> >
> >>>became unnecessary. Simply lengthen runways, and put skid plates on
the
> >>>bottoms of airplanes. With that low coefficient of friction, little
> >>
> > damage
> >
> >>>will be done, and reverse thrust can do the bulk of the work. After
> >>>stopping, just slide some ground-bound wheels under the thing and taxi
> >>
> > it
> >
> >>>away. Thousands of pounds of weight saved. Didn't I see something
like
> >>>that on the cover of Popular Science Magazine circa 1953? The
> >>>Slide-o-Cruiser?
> >>>
> >>
> >>You're not meant to run reverse thrust at low IAS. Also there would be
> >>little directional control, runways would cost more, runway occupancy
> >>times would increase, to name but three other objections that come
> >>immediately to mind.
> >
> >
> > Yes, yes. So, let me see if I have this right. Two identical and
> > identically loaded and flown MD-80s land on parallel identical runways
which
> > I presume, a thunderstorm having been in the area, are wet. One
airplane
> > lands wheels up, and other wheels down, and you can prove that the
> > wheels-down airplane will stop first? Nothing other than braking or
> > airplane-to-ground friction will provide what you call "stopping power".
> >
> > Can we see the work on that, please?
> >
>
> I seem to be a bit short of spare MD-80s right now for doing the
> experiments, and the local airline (which initially was quite
> interested) demurred when I mentioned the gear up aspect. However, the
> underlying principle is quite easy to demonstrate.
In other words, you made a guess. You don't know how many square (inches -
cm - feet - meters) of airplane are going to be sliding on the ground. You
therefore don't know what the coefficient of friction is for that
combination of metal and pavement under the hypothetical conditions, because
you don't know the distribution of weight over the area without the area.
You don't know how the sliding and grinding action is going to affect the
area in contact with the ground, and thereby change the coefficient of
friction, and probably the contact area, as the event proceeds. I think it
is also unlikely that the coefficient of friction is going to remain
constant as the airplane slows down. You don't have information necessary to
calculate the stopping distance for this noisy experiment. You just made a
guess. Nothing wrong with that, guessing is fun to do. But you presented
your guess as some sort of authoritative estimate and then mocked people for
challenging your guess even though you had no way to back it up with even
the most rudimentary calculations.
Did I miss anything?
|
|
| | From: | tadchem | | Subject: | Re: Effect of spoilers on braking | | Date: | Mon, 22 Nov 2004 04:46:56 -0500 |
|
|
|
"AbsolutelyCertain" wrote in message
news:cnr93g$1jr$0@pita.alt.net...
> In other words, you made a guess. You don't know how many square
(inches -
> cm - feet - meters) of airplane are going to be sliding on the ground.
You
> therefore don't know what the coefficient of friction is for that
> combination of metal and pavement under the hypothetical conditions,
because
> you don't know the distribution of weight over the area without the area.
> You don't know how the sliding and grinding action is going to affect the
> area in contact with the ground, and thereby change the coefficient of
> friction, and probably the contact area, as the event proceeds. I think
it
> is also unlikely that the coefficient of friction is going to remain
> constant as the airplane slows down. You don't have information necessary
to
> calculate the stopping distance for this noisy experiment. You just made
a
> guess. Nothing wrong with that, guessing is fun to do. But you presented
> your guess as some sort of authoritative estimate and then mocked people
for
> challenging your guess even though you had no way to back it up with even
> the most rudimentary calculations.
>
> Did I miss anything?
A few things...
The rubber tire uses *static* friction as it *rolls* on the ground. The
landing gear on large jets is designed to get the tires spinning *before*
they touch ground so there is minimal torque on the wheel at the moment of
touchdown. The weight applied to a pneumatic tire causes some deformation
to the tire which is restored by the elastic properties of the pneumatic
tire as it turns. This also heats up the tire. Other than a little bit of
wear to the tread, no material is sacrificed.
A landing skid uses *sliding* friction, an indeterminate amount of material
is *always* lost. Germany actually tried this technique with a small
aircraft during WWII, the Messerschmidt ME-163 "Komet", which had a
'deciduous' gear used for take-offs (it would fall away as soon as the plane
was airborne). I understand the landings were as deadly to the pilots as
fuel leaks (liquid hydrazine and 70% hydrogen peroxide). The problem was
that the skid has no way to adapt to unevenness of the landing surface -
even small pebbles could tear away large chunks of the skid, and buried
stones (the Komet typically landed in open fields) could flip the plane.
Look at the pictures...
http://hans.liss.pp.se/ME163/
http://hans.liss.pp.se/ME163/gallery/
http://www.luftwaffepics.com/lme1632.htm
Pictures showing a pilot beside the plane give a sense of the scale - these
were really small planes!
Tom Davidson
Richmond, VA
|
|
| | From: | Bertie the Bunyip | | Subject: | Re: Effect of spoilers on braking | | Date: | Thu, 25 Nov 2004 05:32:32 +0000 (UTC) |
|
|
| "tadchem"
sednews:dqGdnXyMKd0lKjzcRVn-2A@comcast.com:
>
> "AbsolutelyCertain" wrote in message
> news:cnr93g$1jr$0@pita.alt.net...
>
>
>
>> In other words, you made a guess. You don't know how many square
> (inches -
>> cm - feet - meters) of airplane are going to be sliding on the
>> ground.
> You
>> therefore don't know what the coefficient of friction is for that
>> combination of metal and pavement under the hypothetical conditions,
> because
>> you don't know the distribution of weight over the area without the
>> area. You don't know how the sliding and grinding action is going to
>> affect the area in contact with the ground, and thereby change the
>> coefficient of friction, and probably the contact area, as the event
>> proceeds. I think
> it
>> is also unlikely that the coefficient of friction is going to remain
>> constant as the airplane slows down. You don't have information
>> necessary
> to
>> calculate the stopping distance for this noisy experiment. You just
>> made
> a
>> guess. Nothing wrong with that, guessing is fun to do. But you
>> presented your guess as some sort of authoritative estimate and then
>> mocked people
> for
>> challenging your guess even though you had no way to back it up with
>> even the most rudimentary calculations.
>>
>> Did I miss anything?
>
> A few things...
>
> The rubber tire uses *static* friction as it *rolls* on the ground.
> The landing gear on large jets is designed to get the tires spinning
> *before* they touch ground so there is minimal torque on the wheel at
> the moment of touchdown. The weight applied to a pneumatic tire
> causes some deformation to the tire which is restored by the elastic
> properties of the pneumatic tire as it turns. This also heats up the
> tire. Other than a little bit of wear to the tread, no material is
> sacrificed.
>
> A landing skid uses *sliding* friction, an indeterminate amount of
> material is *always* lost. Germany actually tried this technique with
> a small aircraft during WWII, the Messerschmidt ME-163 "Komet", which
> had a 'deciduous' gear used for take-offs (it would fall away as soon
> as the plane was airborne). I understand the landings were as deadly
> to the pilots as fuel leaks (liquid hydrazine and 70% hydrogen
> peroxide). The problem was that the skid has no way to adapt to
> unevenness of the landing surface - even small pebbles could tear away
> large chunks of the skid, and buried stones (the Komet typically
> landed in open fields) could flip the plane.
>
> Look at the pictures...
> http://hans.liss.pp.se/ME163/
> http://hans.liss.pp.se/ME163/gallery/
> http://www.luftwaffepics.com/lme1632.htm
>
> Pictures showing a pilot beside the plane give a sense of the scale -
> these were really small planes!
>
>
The Germans also landed very large aircraft on skids.
the arado jet bomber, for instance,.
and then there was th eX-15..........
Bertie
|
|
| | From: | JL Grasso | | Subject: | Re: Effect of spoilers on braking | | Date: | Mon, 22 Nov 2004 08:20:54 -0600 |
|
|
| On Mon, 22 Nov 2004 04:46:56 -0500, "tadchem"
wrote:
>The
>landing gear on large jets is designed to get the tires spinning *before*
>they touch ground so there is minimal torque on the wheel at the moment of
>touchdown.
Really?
Jerry
|
|
| | From: | AbsolutelyCertain | | Subject: | Re: Effect of spoilers on braking | | Date: | Mon, 22 Nov 2004 07:28:24 -0700 |
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"JL Grasso" wrote in message
news:10q3te7afm4sud1@news.supernews.com...
> On Mon, 22 Nov 2004 04:46:56 -0500, "tadchem"
> wrote:
>
> >The
> >landing gear on large jets is designed to get the tires spinning *before*
> >they touch ground so there is minimal torque on the wheel at the moment
of
> >touchdown.
Something he might have seen in The Jetsons?
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| | From: | JL Grasso | | Subject: | Re: Effect of spoilers on braking | | Date: | Mon, 22 Nov 2004 09:21:06 -0600 |
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| On Mon, 22 Nov 2004 07:28:24 -0700, "AbsolutelyCertain"
wrote:
>
>"JL Grasso" wrote in message
>news:10q3te7afm4sud1@news.supernews.com...
>> On Mon, 22 Nov 2004 04:46:56 -0500, "tadchem"
>> wrote:
>>
>> >The
>> >landing gear on large jets is designed to get the tires spinning *before*
>> >they touch ground so there is minimal torque on the wheel at the moment
>of
>> >touchdown.
>
>Something he might have seen in The Jetsons?
Well, I'm open to learning new things about aircraft, so let's see!
Cite please?
Jerry
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| | From: | Sylvia Else | | Subject: | Re: Effect of spoilers on braking | | Date: | Tue, 23 Nov 2004 08:06:20 +1100 |
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JL Grasso wrote:
> On Mon, 22 Nov 2004 07:28:24 -0700, "AbsolutelyCertain"
> wrote:
>
>
>>"JL Grasso" wrote in message
>>news:10q3te7afm4sud1@news.supernews.com...
>>
>>>On Mon, 22 Nov 2004 04:46:56 -0500, "tadchem"
>>>wrote:
>>>
>>>
>>>>The
>>>>landing gear on large jets is designed to get the tires spinning *before*
>>>>they touch ground so there is minimal torque on the wheel at the moment
>>>
>>of
>>
>>>>touchdown.
>>>
>>Something he might have seen in The Jetsons?
>
>
> Well, I'm open to learning new things about aircraft, so let's see!
>
> Cite please?
>
> Jerry
>
Or maybe we could take the wedding tackle off the table (those of us
that have it), put it back where it belongs, and just discuss the cost
of carrying the extra weight of the mechanism to spin up the wheels
compared with the cost of the rubber lost on each landing due to the
wheels not spinning.
Sylvia.
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| | From: | Bertie the Bunyip | | Subject: | Re: Effect of spoilers on braking | | Date: | Thu, 25 Nov 2004 05:41:51 +0000 (UTC) |
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| Sylvia Else
sednews:41A254CC.4070403@not.at.this.address:
>
>
> JL Grasso wrote:
>> On Mon, 22 Nov 2004 07:28:24 -0700, "AbsolutelyCertain"
>> wrote:
>>
>>
>>>"JL Grasso" wrote in message
>>>news:10q3te7afm4sud1@news.supernews.com...
>>>
>>>>On Mon, 22 Nov 2004 04:46:56 -0500, "tadchem"
>>>> wrote:
>>>>
>>>>
>>>>>The
>>>>>landing gear on large jets is designed to get the tires spinning
>>>>>*before* they touch ground so there is minimal torque on the wheel
>>>>>at the moment
>>>>
>>>of
>>>
>>>>>touchdown.
>>>>
>>>Something he might have seen in The Jetsons?
>>
>>
>> Well, I'm open to learning new things about aircraft, so let's see!
>>
>> Cite please?
>>
>> Jerry
>>
>
> Or maybe we could take the wedding tackle off the table (those of us
> that have it), put it back where it belongs, and just discuss the cost
> of carrying the extra weight of the mechanism to spin up the wheels
> compared with the cost of the rubber lost on each landing due to the
> wheels not spinning.
>
Oh brother.
bertie
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| | From: | JL Grasso | | Subject: | Re: Effect of spoilers on braking | | Date: | Mon, 22 Nov 2004 15:41:25 -0600 |
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| On Tue, 23 Nov 2004 08:06:20 +1100, Sylvia Else
wrote:
>
>
>JL Grasso wrote:
>> On Mon, 22 Nov 2004 07:28:24 -0700, "AbsolutelyCertain"
>> wrote:
>>
>>
>>>"JL Grasso" wrote in message
>>>news:10q3te7afm4sud1@news.supernews.com...
>>>
>>>>On Mon, 22 Nov 2004 04:46:56 -0500, "tadchem"
>>>>wrote:
>>>>
>>>>
>>>>>The
>>>>>landing gear on large jets is designed to get the tires spinning *before*
>>>>>they touch ground so there is minimal torque on the wheel at the moment
>>>>
>>>of
>>>
>>>>>touchdown.
>>>>
>>>Something he might have seen in The Jetsons?
>>
>>
>> Well, I'm open to learning new things about aircraft, so let's see!
>>
>> Cite please?
>>
>> Jerry
>>
>
>Or maybe we could take the wedding tackle off the table (those of us
>that have it), put it back where it belongs,
"Wedding tackle"? How lewd.
>...and just discuss the cost
>of carrying the extra weight of the mechanism to spin up the wheels
>compared with the cost of the rubber lost on each landing due to the
>wheels not spinning.
A sysytem(s) has already been invented (first iteration in 1942 or so I
believe), and still no mfr has adopted it.
Maybe the manufacturers have overlooked this - why not call them and fill
them in?
Jerry
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| | From: | Sylvia Else | | Subject: | Re: Effect of spoilers on braking | | Date: | Tue, 23 Nov 2004 09:18:43 +1100 |
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JL Grasso wrote:
> On Tue, 23 Nov 2004 08:06:20 +1100, Sylvia Else
> wrote:
>...and just discuss the cost
>>of carrying the extra weight of the mechanism to spin up the wheels
>>compared with the cost of the rubber lost on each landing due to the
>>wheels not spinning.
>
>
> A sysytem(s) has already been invented (first iteration in 1942 or so I
> believe), and still no mfr has adopted it.
>
> Maybe the manufacturers have overlooked this - why not call them and fill
> them in?
I think you spend so much time trying to ridicule me, that you overlook
the substance of what I say.
As I pointed out, there is a cost associated with the mechanism. If that
cost, in terms of reduced payload, extra fuel, etc. were less than the
cost of replacing the tyres that wear out earlier than they otherwise
would, then the mechanisms would be used. Both the manufacturers and
airlines understand simple economics.
As things stand, it's cheaper to replace the tyres.
Sylvia.
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| | From: | JL Grasso | | Subject: | Re: Effect of spoilers on braking | | Date: | Mon, 22 Nov 2004 17:34:01 -0600 |
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| On Tue, 23 Nov 2004 09:18:43 +1100, Sylvia Else
wrote:
>
>
>JL Grasso wrote:
>> On Tue, 23 Nov 2004 08:06:20 +1100, Sylvia Else
>> wrote:
>
>
>>...and just discuss the cost
>>>of carrying the extra weight of the mechanism to spin up the wheels
>>>compared with the cost of the rubber lost on each landing due to the
>>>wheels not spinning.
>>
>>
>> A sysytem(s) has already been invented (first iteration in 1942 or so I
>> believe), and still no mfr has adopted it.
>>
>> Maybe the manufacturers have overlooked this - why not call them and fill
>> them in?
>
>I think you spend so much time trying to ridicule me, that you overlook
>the substance of what I say.
No.
>As I pointed out, there is a cost associated with the mechanism. If that
>cost, in terms of reduced payload, extra fuel, etc. were less than the
>cost of replacing the tyres that wear out earlier than they otherwise
>would, then the mechanisms would be used. Both the manufacturers and
>airlines understand simple economics.
>
>As things stand, it's cheaper to replace the tyres.
No. The article that Mr. Davison posted touched on the correct reasons in
two different replies.
You also may learn more about it if you reasearch in-flight braking, and
the reasons why it is used on most modern heavy aircraft.
Sincerely,
Jerry
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| | From: | Sylvia Else | | Subject: | Re: Effect of spoilers on braking | | Date: | Tue, 23 Nov 2004 11:27:58 +1100 |
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JL Grasso wrote:
> You also may learn more about it if you reasearch in-flight braking, and
> the reasons why it is used on most modern heavy aircraft.
Well, if you knew that, then why didn't you say so in the first place.
Extracting information from you people is like getting blood out of a stone.
Still, an effective technique is now apparent. All you have to do is
make some assertion, and see what comes back in the scrapnel.
Sylvia.
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| | From: | JL Grasso | | Subject: | Re: Effect of spoilers on braking | | Date: | Mon, 22 Nov 2004 21:24:17 -0600 |
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| On Tue, 23 Nov 2004 11:27:58 +1100, Sylvia Else
wrote:
>
>
>JL Grasso wrote:
>> You also may learn more about it if you reasearch in-flight braking, and
>> the reasons why it is used on most modern heavy aircraft.
>
>Well, if you knew that, then why didn't you say so in the first place.
>Extracting information from you people is like getting blood out of a stone.
>
>Still, an effective technique is now apparent. All you have to do is
>make some assertion, and see what comes back in the scrapnel.
Shit! Time for back-up plan.
Jerry
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| | From: | Scott M. Kozel | | Subject: | Re: Effect of spoilers on braking | | Date: | Mon, 22 Nov 2004 18:39:38 -0500 |
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| JL Grasso wrote:
>
> Sylvia Else wrote:
> > JL Grasso wrote:
> >> "AbsolutelyCertain" wrote:
> >>> "JL Grasso" wrote
> >>>> "tadchem" wrote:
> >>>>
> >>>>
> >>>>>The
> >>>>>landing gear on large jets is designed to get the tires spinning *before*
> >>>>>they touch ground so there is minimal torque on the wheel at the moment of
> >>>>>touchdown.
> >>>>
> >>>Something he might have seen in The Jetsons?
> >>
> >> Well, I'm open to learning new things about aircraft, so let's see!
> >>
> >> Cite please?
> >>
> >> Jerry
> >
> >Or maybe we could take the wedding tackle off the table (those of us
> >that have it), put it back where it belongs,
>
> "Wedding tackle"? How lewd.
Sylvia Else Tarver! Splaps Boy tied the knot!
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| | From: | tadchem | | Subject: | Re: Effect of spoilers on braking | | Date: | Mon, 22 Nov 2004 16:42:29 -0500 |
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"JL Grasso" wrote in message
news:10q3te7afm4sud1@news.supernews.com...
> On Mon, 22 Nov 2004 04:46:56 -0500, "tadchem"
> wrote:
>
> >The
> >landing gear on large jets is designed to get the tires spinning *before*
> >they touch ground so there is minimal torque on the wheel at the moment
of
> >touchdown.
>
> Really?
Researching (rather than relying on out-of-date data in my memory) led me to
this:
http://www.sensorsmag.com/articles/0300/14/main.shtml
Apparently it had been done, and is no longer done. I stand corrected (sort
of). My information came from my father, who was an engineer with Lockheed
in the 50's [see the comment by Bob Schaeffer].
To reassure Sylvia, the "spin-up" was accomplished by incorporating diagonal
vanes in the tire sidewalls with a minimum amount of added weight.
Tom Davidson
Richmond, VA
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| | From: | Sylvia Else | | Subject: | Re: Effect of spoilers on braking | | Date: | Tue, 23 Nov 2004 09:22:06 +1100 |
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tadchem wrote:
> "JL Grasso" wrote in message
> news:10q3te7afm4sud1@news.supernews.com...
>
>>On Mon, 22 Nov 2004 04:46:56 -0500, "tadchem"
>>wrote:
>>
>>
>>>The
>>>landing gear on large jets is designed to get the tires spinning *before*
>>>they touch ground so there is minimal torque on the wheel at the moment
>>
> of
>
>>>touchdown.
>>
>>Really?
>
>
> Researching (rather than relying on out-of-date data in my memory) led me to
> this:
> http://www.sensorsmag.com/articles/0300/14/main.shtml
>
> Apparently it had been done, and is no longer done. I stand corrected (sort
> of). My information came from my father, who was an engineer with Lockheed
> in the 50's [see the comment by Bob Schaeffer].
>
> To reassure Sylvia, the "spin-up" was accomplished by incorporating diagonal
> vanes in the tire sidewalls with a minimum amount of added weight.
>
>
> Tom Davidson
> Richmond, VA
>
>
The cost argument presumably still stands up, though. There would be
some extra weight, and adding these vanes would increase the cost of the
tyres. I would suspect that in the mean time, tyre's abrasion resistance
has also improved, so that they better tolerate the sudden spin up.
Sylvia.
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| | From: | Sylvia Else | | Subject: | Re: Effect of spoilers on braking | | Date: | Tue, 23 Nov 2004 14:00:20 +1100 |
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tadchem wrote:
> The rubber tire uses *static* friction as it *rolls* on the ground. The
> landing gear on large jets is designed to get the tires spinning *before*
> they touch ground so there is minimal torque on the wheel at the moment of
> touchdown. The weight applied to a pneumatic tire causes some deformation
> to the tire which is restored by the elastic properties of the pneumatic
> tire as it turns. This also heats up the tire. Other than a little bit of
> wear to the tread, no material is sacrificed.
You probably didn't see this URL that I posted at the beggining of this
thread, before I added the science groups.
http://tinyurl.com/5rs46
BTW, you'll probably need to use IE for this - certainly it doesn't work
with Netscrape 6.0
Look at the fifth slide, which shows the coefficient of friction as a
function of velocity.
As you say, the tyre uses static friction. What do you make of the
variation of the coefficient with velocity? I find its shape rather
surprising - particulary in the way the slope changes sign.
Sylvia.
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| | From: | Bertie the Bunyip | | Subject: | Re: Effect of spoilers on braking | | Date: | Thu, 25 Nov 2004 05:44:34 +0000 (UTC) |
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| Sylvia Else
sednews:41A2A7C4.8060403@not.at.this.address:
>
>
> tadchem wrote:
>
>> The rubber tire uses *static* friction as it *rolls* on the ground.
>> The landing gear on large jets is designed to get the tires spinning
>> *before* they touch ground so there is minimal torque on the wheel at
>> the moment of touchdown. The weight applied to a pneumatic tire
>> causes some deformation to the tire which is restored by the elastic
>> properties of the pneumatic tire as it turns. This also heats up the
>> tire. Other than a little bit of wear to the tread, no material is
>> sacrificed.
>
> You probably didn't see this URL that I posted at the beggining of
> this thread, before I added the science groups.
>
> http://tinyurl.com/5rs46
>
> BTW, you'll probably need to use IE for this - certainly it doesn't
> work with Netscrape 6.0
>
> Look at the fifth slide, which shows the coefficient of friction as a
> function of velocity.
>
> As you say, the tyre uses static friction. What do you make of the
> variation of the coefficient with velocity? I find its shape rather
> surprising - particulary in the way the slope changes sign.
What, to "bumps ahead?"
Dumb cunt
bertie
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| | From: | AbsolutelyCertain | | Subject: | Re: Effect of spoilers on braking | | Date: | Mon, 22 Nov 2004 06:47:53 -0700 |
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|
"tadchem" wrote in message
news:dqGdnXyMKd0lKjzcRVn-2A@comcast.com...
>
> "AbsolutelyCertain" wrote in message
> news:cnr93g$1jr$0@pita.alt.net...
> A landing skid uses *sliding* friction, an indeterminate amount of
material
> is *always* lost. Germany actually tried this technique with a small
> aircraft during WWII, the Messerschmidt ME-163 "Komet", which had a
> 'deciduous' gear used for take-offs (it would fall away as soon as the
plane
> was airborne). I understand the landings were as deadly to the pilots as
> fuel leaks (liquid hydrazine and 70% hydrogen peroxide). The problem was
> that the skid has no way to adapt to unevenness of the landing surface -
> even small pebbles could tear away large chunks of the skid, and buried
> stones (the Komet typically landed in open fields) could flip the plane.
Hence the phrase, "Any landing you can crawl away from ..........."
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| | From: | tadchem | | Subject: | Re: Effect of spoilers on braking | | Date: | Mon, 22 Nov 2004 19:25:36 -0500 |
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| P.S.
Two more considerations to add to the reasons *NOT* to use skids:
1) You can't steer them very easily - unless you strap them to your feet and
stay in the snow!
2) Once an airplane has skidded to a stop you need to be able to move it out
of the way of the next plane coming in to avoid a pile-up at the end of the
runway. If the incoming flights are 2-3 minutes apart (as is typical in a
major US airport when it is busy) this would be hard to accomplish by a
ground crew on a plane without wheels.
Tom Davidson
Richmond, VA
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| | From: | JL Grasso | | Subject: | Re: Effect of spoilers on braking | | Date: | Mon, 22 Nov 2004 21:23:05 -0600 |
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| On Mon, 22 Nov 2004 19:25:36 -0500, "tadchem"
wrote:
>P.S.
>
>Two more considerations to add to the reasons *NOT* to use skids:
>
>1) You can't steer them very easily - unless you strap them to your feet and
>stay in the snow!
>
>2) Once an airplane has skidded to a stop you need to be able to move it out
>of the way of the next plane coming in to avoid a pile-up at the end of the
>runway. If the incoming flights are 2-3 minutes apart (as is typical in a
>major US airport when it is busy) this would be hard to accomplish by a
>ground crew on a plane without wheels.
Whether or not the bottom of the aircraft is fitted with a sacrificial
skid has no bearing on either of your two arguments.
I suppose in both case, you feel that a flaming lump of jumbled metal
would make things better?
Jerry
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| | From: | Sylvia Else | | Subject: | Re: Effect of spoilers on braking | | Date: | Tue, 23 Nov 2004 15:00:25 +1100 |
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|
JL Grasso wrote:
> On Mon, 22 Nov 2004 19:25:36 -0500, "tadchem"
> wrote:
>
>
>>P.S.
>>
>>Two more considerations to add to the reasons *NOT* to use skids:
>>
>>1) You can't steer them very easily - unless you strap them to your feet and
>>stay in the snow!
>>
>>2) Once an airplane has skidded to a stop you need to be able to move it out
>>of the way of the next plane coming in to avoid a pile-up at the end of the
>>runway. If the incoming flights are 2-3 minutes apart (as is typical in a
>>major US airport when it is busy) this would be hard to accomplish by a
>>ground crew on a plane without wheels.
>
>
> Whether or not the bottom of the aircraft is fitted with a sacrificial
> skid has no bearing on either of your two arguments.
>
> I suppose in both case, you feel that a flaming lump of jumbled metal
> would make things better?
>
I think the intended options were using skids or using wheels (with
brakes), rather than simply having, or not having, skids.
Sylvia.
|
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| | From: | JL Grasso | | Subject: | Re: Effect of spoilers on braking | | Date: | Mon, 22 Nov 2004 22:23:30 -0600 |
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| On Tue, 23 Nov 2004 15:00:25 +1100, Sylvia Else
wrote:
>
>
>JL Grasso wrote:
>> On Mon, 22 Nov 2004 19:25:36 -0500, "tadchem"
>> wrote:
>>
>>
>>>P.S.
>>>
>>>Two more considerations to add to the reasons *NOT* to use skids:
>>>
>>>1) You can't steer them very easily - unless you strap them to your feet and
>>>stay in the snow!
>>>
>>>2) Once an airplane has skidded to a stop you need to be able to move it out
>>>of the way of the next plane coming in to avoid a pile-up at the end of the
>>>runway. If the incoming flights are 2-3 minutes apart (as is typical in a
>>>major US airport when it is busy) this would be hard to accomplish by a
>>>ground crew on a plane without wheels.
>>
>>
>> Whether or not the bottom of the aircraft is fitted with a sacrificial
>> skid has no bearing on either of your two arguments.
>>
>> I suppose in both case, you feel that a flaming lump of jumbled metal
>> would make things better?
>>
>
>I think the intended options were using skids or using wheels (with
>brakes), rather than simply having, or not having, skids.
Well, since the discussion was concenring a gear-up landing, having wheels
and brakes is a bit of wishful thinking, eh? I believe he was taking issue
with aircraft having sacrificial skids built into them. I'm not talking
about skids on the outside of the aircaraft, I'm talking about one rather
large block of metal or composite (usually in the center section) which is
designed to absorb the abrasion from sliding down the runway in the event
of a gear-up landing.
From CFR 14:
§ 25.963 Fuel tanks: general.
(a) Each fuel tank must be able to withstand, without failure, the
vibration, inertia, fluid, and structural loads that it may be subjected
to in operation.
(b) Flexible fuel tank liners must be approved or must be shown to be
suitable for the particular application.
(c) Integral fuel tanks must have facilities for interior inspection and
repair.
(d) Fuel tanks within the fuselage contour must be able to resist rupture
and to retain fuel, under the inertia forces prescribed for the emergency
landing conditions in § 25.561. In addition, these tanks must be in a
protected position so that exposure of the tanks to scraping action with
the ground is unlikely.
The requirement for "protected position" is usually met by using a skid to
absorb the abrasion.
But I'm not sure where tadchem got off on using skids as the primary
landing means. I guess I didn't think that he was actually serious.
I guess if the Nazis were running Boeing, we might have some on "large jet
aircraft"...
Jerry
|
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| | From: | Sylvia Else | | Subject: | Re: Effect of spoilers on braking | | Date: | Tue, 23 Nov 2004 15:34:12 +1100 |
|
|
|
JL Grasso wrote:
> On Tue, 23 Nov 2004 15:00:25 +1100, Sylvia Else
> wrote:
>
>
>>
>>JL Grasso wrote:
>>
>>>On Mon, 22 Nov 2004 19:25:36 -0500, "tadchem"
>>>wrote:
>>>
>>>
>>>
>>>>P.S.
>>>>
>>>>Two more considerations to add to the reasons *NOT* to use skids:
>>>>
>>>>1) You can't steer them very easily - unless you strap them to your feet and
>>>>stay in the snow!
>>>>
>>>>2) Once an airplane has skidded to a stop you need to be able to move it out
>>>>of the way of the next plane coming in to avoid a pile-up at the end of the
>>>>runway. If the incoming flights are 2-3 minutes apart (as is typical in a
>>>>major US airport when it is busy) this would be hard to accomplish by a
>>>>ground crew on a plane without wheels.
>>>
>>>
>>>Whether or not the bottom of the aircraft is fitted with a sacrificial
>>>skid has no bearing on either of your two arguments.
>>>
>>>I suppose in both case, you feel that a flaming lump of jumbled metal
>>>would make things better?
>>>
>>
>>I think the intended options were using skids or using wheels (with
>>brakes), rather than simply having, or not having, skids.
>
>
> Well, since the discussion was concenring a gear-up landing, having wheels
> and brakes is a bit of wishful thinking, eh? I believe he was taking issue
> with aircraft having sacrificial skids built into them. I'm not talking
> about skids on the outside of the aircaraft, I'm talking about one rather
> large block of metal or composite (usually in the center section) which is
> designed to absorb the abrasion from sliding down the runway in the event
> of a gear-up landing.
Well, OK, but in that case I think the two of you are talking at cross
purposes. I would agree with your sentiment that it's preferable to have
a sacrificial skid over a disintegrating airframe, but his comments
about airfraft arrival frequency and directional control hardly make
sense in that context.
Sylvia.
|
|
| | From: | Bertie the Bunyip | | Subject: | Re: Effect of spoilers on braking | | Date: | 23 Nov 2004 10:07:48 -0800 |
|
|
| Sylvia Else wrote in message news:<41A2BDC4.3020907@not.at.this.address>...
> JL Grasso wrote:
> > On Tue, 23 Nov 2004 15:00:25 +1100, Sylvia Else
> > wrote:
> >
> >
> >>
> >>JL Grasso wrote:
> >>
> >>>On Mon, 22 Nov 2004 19:25:36 -0500, "tadchem"
> >>>wrote:
> >>>
> >>>
> >>>
> >>>>P.S.
> >>>>
> >>>>Two more considerations to add to the reasons *NOT* to use skids:
> >>>>
> >>>>1) You can't steer them very easily - unless you strap them to your feet and
> >>>>stay in the snow!
> >>>>
> >>>>2) Once an airplane has skidded to a stop you need to be able to move it out
> >>>>of the way of the next plane coming in to avoid a pile-up at the end of the
> >>>>runway. If the incoming flights are 2-3 minutes apart (as is typical in a
> >>>>major US airport when it is busy) this would be hard to accomplish by a
> >>>>ground crew on a plane without wheels.
> >>>
> >>>
> >>>Whether or not the bottom of the aircraft is fitted with a sacrificial
> >>>skid has no bearing on either of your two arguments.
> >>>
> >>>I suppose in both case, you feel that a flaming lump of jumbled metal
> >>>would make things better?
> >>>
> >>
> >>I think the intended options were using skids or using wheels (with
> >>brakes), rather than simply having, or not having, skids.
> >
> >
> > Well, since the discussion was concenring a gear-up landing, having wheels
> > and brakes is a bit of wishful thinking, eh? I believe he was taking issue
> > with aircraft having sacrificial skids built into them. I'm not talking
> > about skids on the outside of the aircaraft, I'm talking about one rather
> > large block of metal or composite (usually in the center section) which is
> > designed to absorb the abrasion from sliding down the runway in the event
> > of a gear-up landing.
>
> Well, OK, but in that case I think the two of you are talking at cross
> purposes. I would agree with your sentiment that it's preferable to have
> a sacrificial skid over a disintegrating airframe, but his comments
> about airfraft arrival frequency and directional control hardly make
> sense in that context.
What a dumb dumb cunt
Bertei
|
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| | From: | tadchem | | Subject: | Re: Effect of spoilers on braking | | Date: | Tue, 23 Nov 2004 16:29:47 -0500 |
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| Demonstrating a quantum increase in intellectual prowess, "Bertie the
Bunyip" wrote in message
news:27eba648.0411231007.e6791d1@posting.google.com...
> What a dumb dumb cunt
That is not only ungrammatical, it is redundant, patronizing, ist, and
gratuitously vulgar. My capacity for such rhetoric was saturated last
November 2nd, so I'll just have to killfile you.
*plonk*
Tom Davidson
Richmond, VA
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| | From: | Bertie the Bunyip | | Subject: | Re: Effect of spoilers on braking | | Date: | Thu, 25 Nov 2004 05:43:58 +0000 (UTC) |
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| "tadchem" sednews:noudnSePwrPqLT7cRVn-
hA@comcast.com:
> Demonstrating a quantum increase in intellectual prowess, "Bertie the
> Bunyip" wrote in message
> news:27eba648.0411231007.e6791d1@posting.google.com...
>
>
>
>> What a dumb dumb cunt
>
> That is not only ungrammatical, it is redundant, patronizing, ist, and
> gratuitously vulgar. My capacity for such rhetoric was saturated last
> November 2nd, so I'll just have to killfile you.
>
> *plonk*
>
See ya!
bertie
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