Fly-By-Wire Flight Controls

Ian wrote:
"Eunometic" wrote in message
oups.com...

Benjamin Gawert wrote:

Eunometic schrieb:


Eunometic schrieb:
It does apply for the PA200 Tornado. The APU is not operable

in-flight,

if you loose both engines and the one-shot battery is down you have to
get out of that thing...


I didn't think Tornado was fully FBW?

The PA200 Tornado is fully FBW with a mechanical linkage backup

system...

Benjamin

Then why does it need a thermal backup battery to remain airborn?


The One Shot Battery is there to provide electrical power to a Fuel pump (or
in combination with a Hyd pump). The engines also need electrical power to
keep their systems running - without electrics, the engines will "run
away" - Very bad thing if you're not near a nice big bit of tarmac......


Or, more importantly, a runway. They tend to be made of concrete not
asphalt.

Dan, U.S. Air Force, retired

Keith Willshaw wrote:
"Eunometic" wrote in message
ups.com...
A higher flying Airbus or B747-400 at 44,000ft might have glided nearly
30 minutes. This suggests that a fighter plane with its lower glide
ratio probably only needs half the amount of time (10 minutes) which
suggests that a thermal battery is possibly more efficient or at least
adaquet whereas an airliner may need twice as much.

What seems extraordinary is that both airbus and boeing designers have
provided insufficient RAT power to opperate all systems: spoilers,
flaps, undercarriage seem to be neglected. This makes an emegency
landing much harder. In both the airbus A330-200 azores and boeing 767
gimli fuel out landing case the lack of spoilers added a great deal of
risk as pilots manouvered agressively to loose altitude and speed for
runway lineup.


If you add more power to the RAT you increase drag and reduce the
glide distance, the record suggests they made the right trade offs.

Apparently in the the lockheed L.1011 Tristar The RAT pressurises a
hydraulic system that can be connected through to the undercarriage,
flaps, spoilers although the system becomes quite sluggish in this mode
and one would expect the pilots to time this opperation carefully.

I would like to see some sort of one shot Emergency Power System EPS
such as a thermal battery to provide supplementary power to allow full
flight control opperation for final 5-7 minutes of flight. There may
be safety issues related to chemical power sources (eg hot thermal
batteries with very high current output or hydrazine gas generators in
a crash) Clearly in fighter aircraft the intention is to allow the
aircraft to get into an ejection zone.

Poor L.1011: a fine piece of advanced engineering that was a commercial
failure (due to delays on the RB.211 engine I think)






(an excellent aircraft in engineering terms that was a commercial
failure)



Keith

John Carrier wrote:
Glide speed generally provides sufficient windmill RPM on the engine(s) to
provide sufficient hydraulic power so that the controls (they don't have to
be fly-by-wire, any irreversible hyd flight control system is effected) have
sufficient pressure and volume to operate normally with moderate control
inputs.

R / John


The B747 and B737 (not sure about the B737 NG aircraft) uses
windmilling of main engines for providing hydralic power but also has
substantial battery backup to provide electrical power. FBW aircraft
are more dependent on electrical power so tend to use RATS but
B747/B737 have power or power assisted controls but not FBW.

The RAT generates hydraulic pressure for the flight controls and then
derive electrical power from a hydraulic motor driven generator.

I believe the DC10/MD11 used ATG (Air Turbine Generator) and thus
reversed the setup with the turbine driving a generator to power a
electrical bus and then deriving hydraulic power from this.

VC10 had both a RAT for Hydraulic power and ATG for electrical.

APU's generally can't be started reliably in flight but 3+ hour ETOPS
certified aircraft like the B777 have special APU that are certified to
start after a cold soak.

Mu schrieb:

Hmm sounds sensible in a Cold War environment with buckets of canned
sunshine being thrown around.

Well, the PA200 is a aircraft from the cold war aera...

But now a question to pilots or folks in the know:
Do they train flying "mech mode" and if so how?
Just in the sims or sometimes for real as in.
"IP to student: I flipped the switch to mech mode. Show me how you
smooth you can land this baby"?

No real training in mech mode (mech mode is an emergency system and not
selectable by a switch, and having it activated once means that after
the aircraft is back on the ground it has to go to service for having
the honeycomb package replaced). You can train that in the simulator,
but usually there is no special training for flying in mech mode...

And if a pilot can apparently fly safe in "mech mode" does that mean
that the Tornado is not inherent unstable like the F16? Or at least
not very inherent unstable?

No, it's not. The PA200 is a very stable aircraft, there are no real
surprises for the pilot when in mech mode. There is a little yaw
tendency that gets suppressed by the yaw damper in CSAS and that shows
up in mech mode, and you loose functions like auto rudder or SPILS (spin
preventer/AOA limiter), stick feel simulation and such. Nothing which is
really a problem for emergency operation...

Benjamin

"Eunometic" wrote

ETOPS ???
--
Jim in NC

ETOPS ???

"Engine turns or people swim". It has an official name too, it is part
of special certification of twins for long range overwater operations
(otherwise you need more engines)

Jose
--
You can choose whom to befriend, but you cannot choose whom to love.
for Email, make the obvious change in the address.

Morgans wrote:
"Eunometic" wrote

ETOPS ???

Extended-range Twin-engine Operation Performance Standards.

Basically, it means the aircraft can operate overwater* as long as it is
within X minutes from a divert airfield (where X is anywhere from 75
minutes to 180 minutes). The idea is that an ETOPS-rated twin-engine
aircraft is reliable enough that even if one engine fails the other will
keep running and keep the plane flying at least the rated time, so that
a safe landing is possible.



*Technically, anywhere more than 1 hour from a divert field, so ETOPS
applies to long-range overland routes too, but the oceanic routes were
the main drivers.

--
Tom Schoene lid
To email me, replace "invalid" with "net"

On Mon, 19 Dec 2005 00:47:23 +0100, Benjamin Gawert wrote:

Steve schrieb:

Its located just behind the left main wheel but stalls when the gear is
lowered, so its a wheels up landing if you've got the balls.

Well done ;-)

Thankyou :-)

And for a bonus point, its not much use below 200Kts anyway.


--
Steve.

On Tue, 20 Dec 2005 13:52:11 +0100, Benjamin Gawert wrote:

And if a pilot can apparently fly safe in "mech mode" does that mean
that the Tornado is not inherent unstable like the F16? Or at least
not very inherent unstable?

No, it's not. The PA200 is a very stable aircraft, there are no real
surprises for the pilot when in mech mode.

A bit sensitive in pitch maybe? :-)

Theres a video at the link below of a GR1 doing a mech-mode approach,
although thats not what the vid is about, hehe. Scroll down to 'Bonus' and
its the 'Near miss' video. A hairy situation.

http://www.fromtheflightdeck.com/videos/index.htm


--
Steve.

Steve wrote:

Theres a video at the link below of a GR1 doing a mech-mode approach,
although thats not what the vid is about, hehe. Scroll down to 'Bonus' and
its the 'Near miss' video. A hairy situation.

http://www.fromtheflightdeck.com/videos/index.htm

Don't you just hate people who don't have their checklists completed
when the take the active? ;


Jack