Aircraft Speed

[stan]

Archived from groups: microsoft.public.games.zone.simulation (More info?)

Here's what I hope is a simple question for the right person:
FS 2004 shows the cruising speed of the Lear jet and the
Boeing 737 (for example) at over 500 knots, yet when I get
up to about 335 knots alarms go off and an "overspeed"
indicator comes on. How come? Any way to defeat the
alarms? The alarms are not altitude dependent.

 

[Guest]

Archived from groups: microsoft.public.games.zone.simulation (More info?)

On Sat, 7 Aug 2004 10:53:29 -0700, "Stan"
<anonymous@discussions.microsoft.com> wrote:

>Here's what I hope is a simple question for the right person:
>FS 2004 shows the cruising speed of the Lear jet and the
>Boeing 737 (for example) at over 500 knots, yet when I get
>up to about 335 knots alarms go off and an "overspeed"
>indicator comes on. How come? Any way to defeat the
>alarms? The alarms are not altitude dependent.

That's because the airspeed gauge is showing Indicated airspeed
not True (ground speed). Remember, air get thinner as you go higher.

Turn on the GPS and look in the bottom left hand corner...it should
show GS Ground Speed.

 

[stan]

Archived from groups: microsoft.public.games.zone.simulation (More info?)

>-----Original Message-----
>On Sat, 7 Aug 2004 10:53:29 -0700, "Stan"
><anonymous@discussions.microsoft.com> wrote:
>
>>Here's what I hope is a simple question for the right person:
>>FS 2004 shows the cruising speed of the Lear jet and the
>>Boeing 737 (for example) at over 500 knots, yet when I get
>>up to about 335 knots alarms go off and an "overspeed"
>>indicator comes on. How come? Any way to defeat the
>>alarms? The alarms are not altitude dependent.
>
>That's because the airspeed gauge is showing Indicated
airspeed
>not True (ground speed). Remember, air get thinner as you
go higher.
>
>Turn on the GPS and look in the bottom left hand
corner...it should
>show GS Ground Speed.
>
>.
>Thanks a million for a concise answer to my question. I
realized there was a difference in TAS and GS, but didn't
think it could be that great.

 

[Guest]

Archived from groups: microsoft.public.games.zone.simulation (More info?)

Note that at high altitudes an aircraft can safely operate at speeds that
would rip the wings off near the ground. There is a lot less air per cubic
foot up there, which results in lower forces on both wing and the probe that
measures the plane's speed. Many jet aircraft routinely operate at altitudes
where the speed that would damage their structure is only a few knots faster
than the minimum speed required to support their weight. The fact that the
airspeed/mach indicator shows an indicated speed is more useful to the pilot
since it better indicates the potentials for lift and structural damage.
Radio beacons, Inertial Navigation systems and Global Positioning Systems
take care of the discrepancies where the horizontal position relative to the
ground is concerned. Exhaustive lookup tables aid with calculating time
enroute and fuel consumption. Winds aloft can make significant differences
in time enroute and fuel consumption between identical aircraft flying in
opposite directions along the same route.

In addition, jets operating at high speeds would present a collision hazard
in the crowded lower altitudes where propeller driven planes operate. The
mismatched speeds would complicate pilot's task of avoiding other aircraft
and the air traffic controller's task of maintaining safe separation. The
occasional collision with a bird isn't quite as disastrous at lower speeds
either. In many areas airspeeds below 10,000 feet are limited to 250 knots
for aircraft not involved in cleared air shows, fighter intercepts and the
associated training.

There's so much difference in air pressure at the altitudes where jets
operate that pressurizing the air for the cabin increases its temperature so
much it has to be chilled back down to a comfortable temperature. This is
despite the subzero temperatures outside.

"landhard" <down@joes> wrote in message
news:2dcah0popi3s929qrfgo0smsf15rbafvad@4ax.com...
> On Sat, 7 Aug 2004 10:53:29 -0700, "Stan"
> <anonymous@discussions.microsoft.com> wrote:
>
> >Here's what I hope is a simple question for the right person:
> >FS 2004 shows the cruising speed of the Lear jet and the
> >Boeing 737 (for example) at over 500 knots, yet when I get
> >up to about 335 knots alarms go off and an "overspeed"
> >indicator comes on. How come? Any way to defeat the
> >alarms? The alarms are not altitude dependent.
>
> That's because the airspeed gauge is showing Indicated airspeed
> not True (ground speed). Remember, air get thinner as you go higher.
>
> Turn on the GPS and look in the bottom left hand corner...it should
> show GS Ground Speed.
>

 

[stan]

Archived from groups: microsoft.public.games.zone.simulation (More info?)

>-----Original Message-----
>Note that at high altitudes an aircraft can safely operate
at speeds that
>would rip the wings off near the ground. There is a lot
less air per cubic
>foot up there, which results in lower forces on both wing
and the probe that
>measures the plane's speed. Many jet aircraft routinely
operate at altitudes
>where the speed that would damage their structure is only
a few knots faster
>than the minimum speed required to support their weight.
The fact that the
>airspeed/mach indicator shows an indicated speed is more
useful to the pilot
>since it better indicates the potentials for lift and
structural damage.
>Radio beacons, Inertial Navigation systems and Global
Positioning Systems
>take care of the discrepancies where the horizontal
position relative to the
>ground is concerned. Exhaustive lookup tables aid with
calculating time
>enroute and fuel consumption. Winds aloft can make
significant differences
>in time enroute and fuel consumption between identical
aircraft flying in
>opposite directions along the same route.
>
>In addition, jets operating at high speeds would present a
collision hazard
>in the crowded lower altitudes where propeller driven
planes operate. The
>mismatched speeds would complicate pilot's task of
avoiding other aircraft
>and the air traffic controller's task of maintaining safe
separation. The
>occasional collision with a bird isn't quite as disastrous
at lower speeds
>either. In many areas airspeeds below 10,000 feet are
limited to 250 knots
>for aircraft not involved in cleared air shows, fighter
intercepts and the
>associated training.
>
>There's so much difference in air pressure at the
altitudes where jets
>operate that pressurizing the air for the cabin increases
its temperature so
>much it has to be chilled back down to a comfortable
temperature. This is
>despite the subzero temperatures outside.

Thanks very much for your encyclopedic answer. Most
educational. Stan
>
>"landhard" <down@joes> wrote in message
>news:2dcah0popi3s929qrfgo0smsf15rbafvad@4ax.com...
>> On Sat, 7 Aug 2004 10:53:29 -0700, "Stan"
>> <anonymous@discussions.microsoft.com> wrote:
>>
>> >Here's what I hope is a simple question for the right
person:
>> >FS 2004 shows the cruising speed of the Lear jet and the
>> >Boeing 737 (for example) at over 500 knots, yet when I get
>> >up to about 335 knots alarms go off and an "overspeed"
>> >indicator comes on. How come? Any way to defeat the
>> >alarms? The alarms are not altitude dependent.
>>
>> That's because the airspeed gauge is showing Indicated
airspeed
>> not True (ground speed). Remember, air get thinner as
you go higher.
>>
>> Turn on the GPS and look in the bottom left hand
corner...it should
>> show GS Ground Speed.
>>
>
>
>.
>

 

[Dave]

Archived from groups: microsoft.public.games.zone.simulation (More info?)

Stan, The GS (Ground Speed)and IAS (Indicated Air Speed
at sea level are the same however, GS is increased aprox.
+2% for every 1000 ft of altitude over the IAS. Good Luck
and Good Flying. Dave
>
>>-----Original Message-----
>>On Sat, 7 Aug 2004 10:53:29 -0700, "Stan"
>><anonymous@discussions.microsoft.com> wrote:
>>
>>>Here's what I hope is a simple question for the right
person:
>>>FS 2004 shows the cruising speed of the Lear jet and
the
>>>Boeing 737 (for example) at over 500 knots, yet when I
get
>>>up to about 335 knots alarms go off and an "overspeed"
>>>indicator comes on. How come? Any way to defeat the
>>>alarms? The alarms are not altitude dependent.
>>
>>That's because the airspeed gauge is showing Indicated
>airspeed
>>not True (ground speed). Remember, air get thinner as
you
>go higher.
>>
>>Turn on the GPS and look in the bottom left hand
>corner...it should
>>show GS Ground Speed.
>>
>>.
>>Thanks a million for a concise answer to my question. I
>realized there was a difference in TAS and GS, but didn't
>think it could be that great.
>
>
>
>
>
>
>.
>

 

[Guest]

Archived from groups: microsoft.public.games.zone.simulation (More info?)

Do not confuse "actual airspeed" with "groundspeed," or
with "indicated" airspeed. They are all different. When
the alarm goes off, throttle back, or you will break up
the plane and have a bad day!

The groundspeed is displayed digitally on the DME near the
CRT display in the Learjet, for example. It will give you
your desired 500+ mph across the ground. You can use the
autothrottle to set the cruising speed so the alarms won't
go off. The target speeds are listed on the reference
section of the checklists.


>-----Original Message-----
>Here's what I hope is a simple question for the right
person:
>FS 2004 shows the cruising speed of the Lear jet and the
>Boeing 737 (for example) at over 500 knots, yet when I get
>up to about 335 knots alarms go off and an "overspeed"
>indicator comes on. How come? Any way to defeat the
>alarms? The alarms are not altitude dependent.
>
>
>.
>