HS 748 - curious.....

[forthbridge]

Cheers Guys. I have not used them when I should (in fact incorrectly as they should be ON for two minutes then OFF before takeoff as they use power) and ON for two minutes BEFORE landing if below 20 c - ON if severe icing is expected, which at FL215 over Alaska in december would be expected

[airboatr]

adenda...

I have an idea that the systems that require voltage to make them work , are wired to a panel,
buss, or fuss box, that would be energized from the battery, which is recharged by either generator or the APU

so if the gennie goes of line the batteries die and the beginning to the end , begins




once when I had both engines failed , I glided to the surface of the ocean and set her down so softly ,
that when I came to a stop the AC floaded for about a min before FS crash detection ended the flight

After all the ac I've seen for FS It's in a class all of it's own ;-)

[forthbridge]

HI Airboatr... yes exactly that happened to me when I first started using the A/C - you get maybe 15 minutes before one, then both engines go off line if you neglect to fire up the generators. On this recent failure, I got maybe 250 miles on the remaining engine. All the switches were OK (position wise) except the Gen fail light illuminated on the panel, I got the smoke and RPM went off. I'm always cautious about starting the airframe and engine deicing until both generators show 'producing'. TBH I've consistently left the fuel heaters on below FL50, off above, and never had this issue before......

[airboatr]

Hi Jim
that problem solved, the other systems I operate is fuel trim and throttle
the quick way I do it is
to set fuel to 100 percent and depending on outside temps then full throttle for take off
once up ... gear flaps bla bla bla
back off throttle and reduce fuel mixture to fifty percent and then run the engines so I keep the operating temp aroun 700 or something
like 675 at cruise ??? ( this will change engine RPM as well and also can burn up the engine if you run them to high
then on desent reduce fuel mixture to zero and whatch running up the engines to quickly if you need more speed on finals
. the feathers pop off ..

......
edited

[Viscount Cornbank]

The power unit de-icers should be on for all conditions of flight where the OAT is below +10'C, The slow cycle is used below -6'C. So long as the green lamps are cycling, and the ammeter showing sufficient current draw, the system should be working correctly.

Fuel heaters should be off for take off (they use compressor bleed air) and switched on in flight if severe icing or low temps are anticipated. The figure the filters will ice up at is programmed around the -20'C mark. The heaters are also turned on for two minutes during the approach, but must be off for landing.

With the benefit of hindsight, the controls should have had an Auto setting as fitted to most production aircraft.

The fuel trimmers, if incorrectly set, can allow an overtemp situation to arise, however they have no influence over RPM in the constant speeding range. ;-)

cheers

Fraser

[airboatr]

Fraiser I stand corrected.
thanks for not letting any misinformation stand.

good thing the original engineers and Rick Piper built it heavy duty enough
to handle the torture I put it through.

[forthbridge]

Cheers Fraser

I pretty much reckon that there's been a fuel issue with the heaters being off, and also I was using slow cycle on the engine deicers, so I will not make the same mistake next time!!!!!

[emfrat]

adenda...

I have an idea that the systems that require voltage to make them work , are wired to a panel,...., or fuss box,

;-) Isn't that the part of the CVR system which is always yelling stuff like 'Sink Rate!', 'No Gear!', 'Pull Up, Pull Up!' just when you need to concentrate on landing the beast?



MikeW

[airboatr]

thats nalis on the chaulk board in this forum section, We are speaking of a Classic British Aeroplane HS 748 .......
somehow your sound packs are messed up if your hearing that. OR

maybe your looking for the hitech airplane thread ..... down the hall , thrird forum on the right.

[emfrat]

maybe your looking for the hitech airplane thread

No Thanks - I believe the expression 'airplane' comes from a form of language used in the earlier Colony, and as such should be utterly cryit doon and forsworn.
I greatly enjoy using the HS748 and the Vanguard, and have even been known to use Caravelles and VC10s, because they are classic flying machines, with no FMCs or glass panel displays, to reduce intrepid Granpa from a pilot to a systems minder. :-(
But you are right - the fuss box has only become necessary in recent years, and the HS748 doesn't have one. Many thanks for creating such a useful phrase

ATB
MikeW