Archived from groups: alt.games.microsoft.flight-sim (
More info?)
I remeber taking as flight from Dallas to Colorado Springs in on a Fokker
100 and loved the plane.
The PMDG 737 I'm flying in the simulator has the noise level just about
right when the speed brakes are deployed. You can see why passengers take
notice, especially those not in love with flight
. People like me and I'm
sure most of you folks find it fun IRL to watch, feel and hear the activity.
Mike
"Oskar Wagner" <rengaw@swissonline.ch> wrote in message
news:dfcoat$k51$1@news.hispeed.ch...
> The Fokker 100 has a unique configuration in this respect. Liftdumpers are
> referred to as large panels (don't recall whether there are 4 or 5) on
> each upper wing surface. They are exclusivley used to "dump lift" in case
> of T/O abortion or upon landing. Operation is automatic with no manual
> extension possible. They are armed before T/O and before LDG. In case of
> T/O abortion the panels are fully deployed upon reaching idle stop of the
> throttles AND speed above a certain threshold (can't remember 70 or 80
> KTS). On landing deployment is controlled by a combination of wheel
> spin-up and main gear strut loading.
> The speedbrakes on the Fokker 100 are of the butterfly type at the
> rearmost end of the fuselage. unfortunately the F100 had these brakes also
> only as an ON/OFF feature, whereas it's predecessor F28 could deploy them
> stepwise. These airbrakes are very effective and lack any kind of
> aerodynamic noise or shaking. And furthermore as they do not interfere
> with aerodynamics they were useable throughout the whole flight envelope
> inclusive full flaps! An ermergeny descent from FL350 down to FL100 would
> usually take less than 4 mins. (on medium weight of course) as you could
> literally "suspend the A/C from it's tail" and reach AVERAGE descend rates
> of 6000+ FPM!
> BTW the F100 has been my favourite A/C IRL as you could handle it like a
> C150 and still operate it like a modern CATIII airliner... ;-))
> --
> Oskar Wagner
> (retired Captain)
>
> Remember, in the great scheme of things, we're all small potatoes....
>
> "DANNY" <drmckee@bigfoot.com> schrieb im Newsbeitrag
> news:OMkSe.20468$ih4.1823@fe02.lga...
>> Nice post, Cap'n Wagner. You mention Fokker 100 in your post. This is
>> my aircraft of choice after I downloaded it 3 weeks ago. I mostly fly
>> GA type craft. I read about 'lift dumpers' in the checklist. What is
>> difference in lift dumpers and air brakes?
>>
>> "Oskar Wagner" <rengaw@swissonline.ch> wrote in message
>> news:dfcict$edu$1@news.hispeed.ch...
>>>
>>> "Gary L." <noone@123.net> schrieb im Newsbeitrag
>>> news:EL6dnWlrer1ZX4TeRVn-iw@comcast.com...
>>>>
>>>> "Gregory" <flightsim.maps@bkwds.comcast.net> wrote in message
>>>> news:niejh1hr1mbtin0bf9ph15214b21jc9mnm@4ax.com...
>>>>>
>>>>> What's the usual `threshold of passenger discomfort' descent rate?
>>>>>
>>>>> As mentioned.. cargo pallets don't mind too much.
>>>>
>>>> I would guess 3600 FPM would be pretty bad, you would feel a sense of
>>>> weightlessness that would not be considered comfortable. If you're
>>>> just hauling pallets then I would mostly be concerned with not
>>>> overspeeding and making sure I'll be able to slow down in time for
>>>> approach.
>>> Why? If you're steady at 3600 FPM your vertical acceleration is exactly
>>> 1.0 G ;-)
>>> Let me add a bit from R/L experience. As stated correctly the "normal"
>>> descent rates would be something around 2500-3000 FPM above FL100 and
>>> around 1000-1500 FPM below FL100. These rates will give you (depending
>>> or your descent speed of course) around 5° descent path about FL100 and
>>> 3° below FL100.
>>> Now the main question is: why do you need to increase you ROD? For a
>>> normal and properly planned descent there's of course no need to do
>>> that. But IRL some odd factors (mainly ATC, but sometimes also
>>> obstacles) will often play havoc to your planning and then you will have
>>> to adjust your descent inorder to re-gain your optimum path.
>>> There are generally three options to achieve that:
>>> 1. You fly some additional distance
>>> 2. You increase the ROD momentarily
>>> 3. You use speedbrakes
>>> or a combination thereof.
>>> As you might guess these options are already ranked in relation to
>>> passenger comfort. Flying additional distance can sometimes be the only
>>> means if you're already vecored for approach, some flaps set, at the max
>>> speed for flaps and (depending on A/C) not allowed to use speed brakes
>>> anymore. Increasing the ROD is the most comfortable means for path
>>> corrections above FL100 where speed is usually up to you still. And
>>> believe it or not, it is easily possible to increase the ROD to 4000 FPM
>>> without scaring the passengers, if you do it smoothly and not for a too
>>> prolonged time (the airspeed limitation would be exceeded anyway). Using
>>> speed brakes is the most common thing you would think about but in fact
>>> the least comfortable item. You should mainly use them for what they are
>>> designed: to blow off speed. If you fully use it during descent and try
>>> to maintain speed you will be surprised to easily reach 6000+ FPM and
>>> your passengers will not be very happy about the shaking and shivering
>>> of the whole A/C (especially on high speeds). FS' speedbrakes are
>>> generally poorly simulated as there's only a on-off position and their
>>> effectiveness is generally too high.
>>> Now of course IRL there are (unlike in FS) also intermediate positions
>>> for the speed brakes and this will allow you to do a high ROD for quite
>>> some time without too much aerodynamical noise and thus without scaring
>>> the passengers too much ;-). Furthermore the speedbrakes (talking about
>>> speed brake/spoiler panels on the upper surface of the wing, not pure
>>> aerodynamical brakes like on Fokker 100, BAe146 etc. ) will reduce lift.
>>> Therefore the pitch will increase und thus reduce the nose-down feeling
>>> inside the A/C although it descends at a quite high angle. Oh, and
>>> something I almost forgot. If you have to correct on your descent path
>>> be sure your throttles are in idle! You wouldn't brake and accelerate
>>> simultaneously in your car, would you? So much for today
🙂)))
>>> --
>>> Oskar Wagner
>>> (retired Captain)
>>>
>>> Remember, in the great scheme of things, we're all small potatoes....
>>>
>>
>>
>
>
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