HS748 Hotel Mode?

[Viscount Cornbank]

BEA had a separate "Scottish Routes" Viscount checklist for internal starting and the order was revised to 2, 1, 4, 3; each engine being wound up to 11000 rpm from the normal 7500rpm idle and the generator checked on line before starting the next.

Cheers

Fraser

[dfarrow]

Hi guys , Garry , Nigel , Dave 'n Fraser , all sound right . The Dart could do battery start ...'tho not desirable . Ben that's right 4 blades would get 360 degrees rotation for Garry's gas !
The PWC 127 on ATP , is if memory is correct a free turbine , so we just wiggled the prop or watched it windmill 'cos it was not turning engine core . Dave , that must have been a sight a Tyne on battery start 900C shows how tough that technology was , and no melted bits out the back . Those temps for normal maxs did not come in until CFM-56 and RB211-524 G/H . Speys , JT-8s and Rb211 -22s generation were maxed at about 600C . Fraser , sadly missed Viscounts and waited 16 years to get to Highland Division, 'n then missed Budgies . Once you'd got one turnin' 'n burnin' , wound the genny up , the other or others were easy to light up . With jets if APU and GPU u/s , you could just about do batt. start ,'tho they preferred ground A/C power . Get one going , then open the tap a bit and cross bleed air 'to start others . You did need ground air 'cos jet starter motors are air driven . Indeed a mate got stuck in Goa . Took an old Tristar in with no APU . Indian ground engineer '' indeed sirs , the ground air start has very lots of puff '' ! [So shut down all engines]..... But not enough for a 25 year old RB 211-22 , they had to wait 24 hrs 'til a 737 came in on a schedule , but with 100 yds of hose to connect his belly engine air duct to the Tristars .... open the 73 taps and thats '' lots of puff ''. We'd heard the rumour and were the crew next in with same a/c . Kept No2 eng. running for nearly 3 hrs .

Dave ,the other 1/2 arranged a surprise b'day visit to Brooklands the other day , great day out , huge changes since the Merch landed ; and to cap it all the lass [ well she is 4 yrs younger than me ] who showed us round .. I was at school with in '68 !

ATB dave f

[Garry Russell]

Channel Airways modified their Scottish Flyer Viscount for self starting by installing extra batteries. Not sure if they did that to the 748 as well.

Aurigny had trouble with their Twin Otters trying to hot start on short runs. In those days they couldn't afford a GPU so they kept a hand truck full of heavy duty lorry batteries. These were all linked together and attached to an aircraft plug. After use it was pushed back into the luggage reclaim area and plugged into the mains.

I've seen on the net Viscount self start and instead of the normal 4321 start they start an inner first...guess that to do with the generators as in it's the outers they shut down after landing.

that would men then an early 700 would have to start an outer as they had the generators on the outers and used to shut the inners down after landing...yes they were mixed up sometimes and the wrong two shut down.

[dfarrow]

Just see Viscount crew going ''Whoops'' ! Garry the Twotter mod sounds just like trolley accs. of Spitfire days . We even have to do that with Cherokees on v. cold winter mornings .. indeed one does not have an external plug ...... so jump leads from the Landrover fire truck , direct to a/c battery .

Rgds Dave f .

[Garry Russell]

Thing about the Twin Otter unit...it worked.

Waht more could you ask for at a fraction of the cost of a GPU

Jersey Airlines/BUA/BUIA used a farm tractor to get the Heralds going

[Motormouse]

Trolley-Accs survived well into the 1990's with Betty Windsor's flying circus, for supplying 28V DC power.

Done battery start on F.27 with Darts, battery had to be in good condition, but EGT temps were still up there!
Reason for pulling thru the Dart before start (IE turnround check) was to make sure it was free to rotate for start, turbine could
get locked by differential cooling within the engine.

Saab 340 could also do 'Hotel' mode, difference between these types (engines-wise) is the use of the 'free power-turbine' or 2-shaft engine, where there are separate power section turbine (aka gas generator) to propellor turbine section. As mentioned, Dart is a single shaft engine, so its' not possible, likewise the Garrett (now Honeywell) TPE331 also single shaft.

ttfn

Pete

[dfarrow]

Pete , would that tie in with faint memory of seeing Jetstream 31 crews pulling 'thro 't prop ?
Casing cooling reared it's head in about 1990 [ B4 the ATP got a sim in '92 ish ] . We did 6 monthly base chks on the a/c , engine failure on t/o was to zero thrust ... but mandatory was an engine shut down and relight at altitude . You did the one on your side , and to see a 6 bladed 16ft diameter prop stationary and feathered outside your window , late on a cold , blowy , winters night , somewhere North of Prestwick .... really concentrated the mind on looking after our then '' precious '' engines . Well one night a mate chatted on a bit long .. start button eventually pushed .. nothing ... casing had cooled and shrunk more than the engine core .. totally jammed .. Mayday went out and he finished his base check with a real single engine landing back into Glasgow .

PS anyone know if Fighter Control website is down ? or is it my finger trouble ?

ATB Dave f .

[NigelC]

TPE331 on the J31 was pulled through to stop shaft bowing due uneven cooling.

[Motormouse]

TPE331 on the J31 was pulled through to stop shaft bowing due uneven cooling.

He-he, I have those and J41 on my type ratings too.
Uneven cooling indeed would cause shaft bowing, and the curvic coupling to lock.

Ttfn

Pete