Trident optimum cruise altitude?

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OZflyer
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Trident optimum cruise altitude?

Post by OZflyer »

Have downloaded both the T2 and 3 and look forward to some flights in them. Currently getting used to the Trident 2 with some flights. But I was curious what is a recommended cruise altitude for a given weight?
The manual says from 25-36,000ft. I was looking for a more specific guide if there is one out there?
Any help greatly appreciated.

adysmith
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Re: Trident optimum cruise altitude?

Post by adysmith »

28 - 29 will give you best airspeed (cruises at Mach.85) but 35 -36 will give best fuel consumption.

If your climb speed reduces to below 5000 FpM you have got as high as it wants go go at that weight.
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Re: Trident optimum cruise altitude?

Post by TSR2 »

adysmith wrote:
14 Dec 2020, 15:31
28 - 29 will give you best airspeed (cruises at Mach.85) but 35 -36 will give best fuel consumption.

If your climb speed reduces to below 5000 FpM you have got as high as it wants go go at that weight.
I take it that should be 500 ft/m?
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adysmith
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Re: Trident optimum cruise altitude?

Post by adysmith »

:doh: Yeah, 500 Fpm, must have been on the :guinn: 8)
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Re: Trident optimum cruise altitude?

Post by TSR2 »

Either that or they'd fitted reheat to your Speys :lol:
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dfarrow
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Re: Trident optimum cruise altitude?

Post by dfarrow »

Gents , in spite of Chrissy Spirit Ady has it right .
Best TAS was FL 280-290 . Seem to remember M.8 and 320 kt IAS co-incided .
LHR-GLA-LHR early on was 230-250 and fast , M.86 . We were selling speed , after all it's a Jet a.c . not T/prop ..... Always a pilots reason to go fast ..
Later fuel became expensive , so Northbound was 310/350 M.8 , Southbound 330/290 , too short to get to 370 .
Into Europe was 290 to start [ if heavy , long route T3 ] , then 330 , occaisional 370 when light ; or cold air . Scandi in winter was straight to 370 in a T2 . Even got to 390 once [ manual flying was ok on instruments , but did not like flying 25 degrees of bank whilst looking down outside ! 6 1/2 NM straight down to snow seemed uncomfortable , so back on instruments ] .
TLV-LHR in a T2 was max range against the wind , so we'd start at 280 , burn off fuel then 310 , later 350 . Never 390 .
In later years with the wing strengthening plates bolted on , would have to tech stop for a 'gas 'n go' . Normally P3 was tasked with checking which W. European station had the best lunch allowance . Thus knowledge of current European exchange rates was crucial . Normally Germans or Swiss competed , but sometimes Netherlands [ if we could get that far ] .

rgds dave f.

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Re: Trident optimum cruise altitude?

Post by adysmith »

I remember when I worked at "London Control" (Air Traffic at West Drayton centre) and one day, with howling north westerly winds, a Trident from possibly Yugoslavia somewhere, had its ETA at London FIR boundary revised three times and eventually arrived in UK an hour after first ETA.

Pilot asked if any holding for Heathrow, TMA crew chief said once or twice around Lambourne, pilot replied negative unable to hold, diverting to Manchester, so maintained 350.

Overhead LAM crew chief says "we'll take him straight in for 28 Right (as it was in those days).

LAM is just over 20 miles from touchdown with a direct approach to 28R and the aircraft is at FL350.

It was established on the Glide Path at EIGHT miles from touchdown!!

Never seen an aircraft descend so fast in 47 years in ATC.
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Re: Trident optimum cruise altitude?

Post by TSR2 »

It’s these nuggets that I absolutely love reading on here. Cheers lads 🍻
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dfarrow
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Re: Trident optimum cruise altitude?

Post by dfarrow »

If ok ? I'll continue the tale . For practice one evening empty from GLA inbound to Bovingdon , delayed descent until ATC really worried !
1 and 3 closed , 10,0000 reverse ; No2 pulled back gently to idle [ as pressurisation comes from No 2 LP bleed , with below 10,000 rpm bleed changes to HP bleed , with a surge . Thus 10,000 rpm normal min. with pax ] , MMO/to VMO , speedbrakes out . We got 17000 ft/min descent rate . At 7nm/min , thats 14 nm from 350 , 6nm/min [ headwind] = 12nm ... Very little dist to slow down in that config ..... Job done , but 3 X table is working hard , making sure reverse is cancelled is crucial .
Forgotten the gear limit speed , but slow to that , get gear down , and down we go again
Remember Boeings , slow to 280 kts , gear down accelerate to 320 kts with it down , get back in the slot ...Dist / Ht [ 3 X table ] . Gear up ... confused the cabin crew and pax. somewhat . Best was into Moscow in 767 , bad descent clearance... gear down FL 280 , speedbrake out , 320 kts ..we got in .

rgds dave f.

PS Ady , would you have known Clacton sector guys ..Chas Davis ? perchance ..

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Re: Trident optimum cruise altitude?

Post by adysmith »

PS Ady , would you have known Clacton sector guys ..Chas Davis ? perchance ..
I was only at West Drayton for about nine months in 19745/6, couldn't really remember anybody.

I seem to recall some early tridents could isolate the nose gear to keep it up as it had a much lower speed limit than the main gear?
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