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-   -   Trident autothrust system and autoland (https://www.pprune.org/tech-log/434496-trident-autothrust-system-autoland.html)

Prober 2nd Dec 2010 22:04

Blind Pew and Comet Fin
 
No, I know who I think it was. All I can say is that Capt O was NOT cocky, but apart from that I had better go no further.
Prober

petermcleland 2nd Dec 2010 22:17


Originally Posted by dixi188 (Post 6098405)
I thought the Trident had Decca Harco navigation with moving map display.
I seem to recall that it was fitted to the BAC 1-11s of BEA also.
I saw a few of these at Hurn in the early '70s.
I also worked on a Jetstream and a Hughes 500 with Decca Danac which was similar to the Harco.

The Super 1-11 had Harco and I loved it...I only flew it as a First Officer and I remember that some Captains were not to happy with it. I remember you had to remember a particular circuit breaker to punch in and out a few times on the first trip of the day if it was reluctant to wake up...After that it was good as gold!

I never flew the Trident as a First Officer but I flew the Trident 3 as Captain from 1975 till it retired in 1985...36794 in your logbook if you flew with me :)

Trident Sim 2nd Dec 2010 23:41

Peter


36794 in your logbook if you flew with me
My logbook has your signature and that very number by some sectors on 05 Oct 83 and also 10 Feb 84.

And a similar signature on my membership card for a club in North London!

Good to hear from you, and I trust all is well with you Peter!

Best Regards

Trident Sim

blind pew 3rd Dec 2010 07:24

Trident simulator visual.

The Trident sim was fitted with a visual display - it was a rubber conveyor belt around 6 ft wide and 20 ft long and mounted vertically.

The black and white TV camera was mounted above it and positioned by two threaded rods to give vertical and horizontal displacement from the belt centre line.

The cloud base was controlled by a sheet of frosted glass positioned in front of the camera.

The airport buildings and runway were made of paper and card with trees and grass made form those bits of kit used by model railway enthusiasts.

On one of the last exercises taken by a non flying simulator instructor I was given a main gear collapse after landing, the belt flexed and the camera lens touched the paper runway.
Unfortunately for the crews for the next few days the lens tore the paper which proceeded to peal away in an ever increasing roll.
I shouted to my fellow trainee to duck as we were going to hit a road roller and we careered across the tarmac and destroyed the hangar.

We P****d ourselves and were taken down into the guts of the machinery to see the results of our incident - looked like the bark on a silver birch.
The instructor had humour failure and talked about the consequences for us but after I reminded him that he had initiated the gear failure he calmed down but still didn't see the funny side of it!

Fortunately never did the Trident high fly but was told of a stick push exercise which nearly went wrong - the nose just remained pointing skywards after the push fired - it took several seconds before it slowly descended!!!!
Believe it was stopped soon afterwards.

Did a High fly on the Duck though - scared me s******s.
We didn't do the full Trident stall rubbish but dutch roll recovery. I still believe that dutch roll was a necessary exercise whereas the stall exercise was stupidity personified.
The Duck had a periscope to observe the huge T tail. The exercise was limited to 30 degrees of bank after a trainee had put in the wrong correction with 60 degrees of bank and got the wings through the vertical.
I am still amazed how much the T tail flexed without breaking off - the tips must have moved at least five feet.

My only real emergency was a dutch roll type of incident on the Duck when we thought it was going to break up - after declaring a mayday, reversing course and initiating the descent I decided to try and hand fly it - contrary to my trident teachings - the movement had got so bad that ceiling panels were falling down.
Punched out the A/P and the dutch roll type of movement stopped - runaway roll or yaw damper which apparently had never happened before.
Got plastered in Hong Kong.

Wookey 3rd Dec 2010 08:45

Moving Map Display

Thanks for the explanations so far. This is probably a stupid question but looking at the picture link from slast's post it seems that the map movement was up and down ( north/south) while the pointer/marker could track sideways (W/E). What happened if you were flying a sector with a significant W-E component? Was the map scale adjusted to allow for the travel limitattions of the marker. If this was the case how positionally accurate would some of the longer W-E sectors be, say London - Moscow (if the Trident operated this route).

THICKO 3rd Dec 2010 09:25

I seem to remember that the map roll was oriented with the E-W bit to N-S if you see what I mean! :)

Wookey 3rd Dec 2010 09:43

Wow bet that was interesting. Cant imagine trying to read my sat nav rotated through 90 degrees !

DozyWannabe 3rd Dec 2010 11:02

It's what you're used to, isn't it? Modern civilian satnav wouldn't hit the market until nearly 40 years after the Trident first flew!

The technology might have been a bit steampunk by comparison (with attendant reliability issues), but some of the innovations in the Trident's avionics were truly special.

I don't think she'd have had the range for London to Moscow though... ;)

petermcleland 3rd Dec 2010 11:07


Originally Posted by Trident Sim (Post 6098869)
Peter



My logbook has your signature and that very number by some sectors on 05 Oct 83 and also 10 Feb 84.

And a similar signature on my membership card for a club in North London!

Good to hear from you, and I trust all is well with you Peter!

OK, I know who you are then...How nice to hear from you again. Yes, all is well with me I took early retirement when the Tridents went and I came to the Southwest with my boat and married again. Are you retired now?

Wookey 3rd Dec 2010 11:10

Longest sector I travelled on a Trident was Tel Aviv - LHR (needed a tech stop in geneva as I remember) which has a significant W-E and N-S component. Again can I ask if the map scale is adjusted to allow for this and if so how accurately were you guys at the front able to establish your position?

DozyWannabe 3rd Dec 2010 11:22

I have no personal experience, but there's a good thread on it here...

http://www.pprune.org/tech-log/38428...echanical.html

ChristiaanJ 3rd Dec 2010 11:28

Wookey,
London-Rome would also be SE-NW.
I hope somebody will confirm this, but I would expect they would be route maps, oriented along the track from A to B, rather than oriented N-S or E-W, and that when operating a given route you would have loaded the relevant map.
Not sure how you coped with a significant diversionn though.

This was long before you could put the entire map of Europe and the display electronics into a little box the size of a cigarette package .....

CJ

petermcleland 3rd Dec 2010 11:56

No, no, each sector had its own roll and it was track orientated...Same as Harco. You picked up the map roll with all the other clutter for the nav bag at briefing. Navigation on the Trident was certainly NOT done with the moving map...It was done with VORs and NDBs as indicated on an RMI. You could lock the autopilot to a VOR radial and uncage the drift shutter if you wished but mostly the autopilot would be locked to Heading and the handling pilot would steer with the heading pointer knob on the compass, changing heading as the RMI needle swung round to indicate the passage of a fix and make a small allowance for drift as appropriate.

We didn't have glass cockpits in Tridents you know!

Here an old picture in the cruise...Note the MachNo:-
http://www.petermcleland.com/trident/Trident010.jpg

WHBM 3rd Dec 2010 12:10

Seeing as all you great Trident guys are here, can I please ask a few questions.

How much was the extra "half engine" actually used on the Trident 3B, was it only if the boost was really needed ? Was it eventually given up and removed ?

Why was the nosewheel offset when virtually every other manufacturer managed to design it in the centre. Did it make any difference when taxiing ?

As the Trident was used on many of the sectors to socialist eastern Europe at the time (1960s-80s), what were the loads like ? Is it true that these trips were often operated virtually empty ?

Wookey 3rd Dec 2010 12:28

Great picture Peter and thanks for the explanation. I think I now understand the process much better!!
Mach no. noted as well. I seem to recall from a friend who used to fly Tridents that he called the T2 the GT version as it had better performance than the other variants.

petermcleland 3rd Dec 2010 12:54

Yes the T2 was the sports car varient and it climbed higher up to about 42,000 feet...The T3 was limited to 35,000 feet and had no "Drop Down" passenger oxygen system. The plastic Boost Engine had 5500 lbs of thrust and you used it for take-off if the runway length or air temperature were limiting. You could also light it in the air if extra thrust was required if you had lost a main engine.

I did lots of Warsaws on the T3 and it was always very full...Often with no seats left at all.

The sideways retracting nosewheel saved an enormous amount of space to put the electronics bay in.

Cremeegg 3rd Dec 2010 12:56

Moscow was certainly a regular non-stopper with, I believe, only T2's. My father had an unscheduled week there trying to fix a couple of errant starter motors. Remember him talking about some "interesting" readings on the radiation meter as they flew over certain parts of eastern Europe.

Tel Aviv also a regular non-stopper - out and back. Again I think only with the T2. Used to have huge bags of citrus fruit brought back from those trips that the family much enjoyed.

bizdev 3rd Dec 2010 16:15

Off Set Nose Gear
 
I was told that because the Cat3 autoland was so accurate the nose gear had to be offset to prevent discomfort to the pax as the nose wheels would be bumping along the runway lights!!!!!! :E (I was an apprentice engineer at the time and believed everything the old salts told me)

WHBM 3rd Dec 2010 16:54


Originally Posted by petermcleland (Post 6099836)
...The T3 was limited to 35,000 feet and had no "Drop Down" passenger oxygen system.

All those years of pax briefings on the Shuttle T3s (and also the T1s they used at first) and I never noticed this. The Caravelle was the same but when these were sold to United Airlines in the US the FAA would not allow this and they had to be re-engineered with an overhead oxy system. The Trident of course was never certified in the US - or was it ?

petermcleland 3rd Dec 2010 17:33


Originally Posted by WHBM (Post 6100309)
All those years of pax briefings on the Shuttle T3s (and also the T1s they used at first) and I never noticed this. The Caravelle was the same but when these were sold to United Airlines in the US the FAA would not allow this and they had to be re-engineered with an overhead oxy system. The Trident of course was never certified in the US - or was it ?

That was the reason for the 35000 feet altitude limit...No drop down Oxy. No, I don't think it was ever certified in the US.


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