Trident Water injection

[WHBM]

Originally Posted by bcgallacher

why did you fly to Munich? The accident happened in Hamburg,

Paninternational HQ was in Munich, presumably it was more of a procedures than a wreckage investigating team. German holiday operators at the time commonly had one aircraft in each major city, all of which operated on the same day of the week out to each holiday destination in turn. The airline was shut down a month after the accident.

[CV880]

CV880 produced all that smoke without water injection. After a high power run up the ramp behind the engine would be covered in a layer of black soot.

[bafanguy]

Originally Posted by CV880

CV880 produced all that smoke without water injection.

Here ya go:

http://www.socimage.com/media/171929...471_5686655169

https://www.dailykos.com/stories/201...ns-Convair-880

[condor17]

Gripper , was it 120 L or 120 Kgs 'ish , and gave 360kg ish ? increase in RTOW ? Memory faded and T2 manuals went to the Sim guys . Came on-line early '74 , and never used it .

rgds condor .

[777fly]

I was a FO on the Trident 2 when it was first introduced in the 70’s. I remember that the water injection system was only operational for a year or two before it was inerted and never used again. If memory serves this was due to limited performance gains and system unreliability. The system sometimes (embarrassingly) failed to work when selected due to pump failure and meant delays to empty the water tank, or early shutoff left water in the tank. I don’t remember a way of jettisoning that water, it never happened to me. I experienced two takeoffs out of the old Nicosia airport in Cyprus in the 40C heat of summer using the injection system. The technique was a standing start, holding on the brakes, then opening up to full thrust. Three toggle switches below the relight switches started the water injection and proper operation was confirmed by three green lights coming on below the engine thrust percentage gauges. The increase in performance was noticeable and lasted for just a minute or so until the water tank ran dry. This left the aircraft wallowing at 1500 ft or so in ISA +25 air and it took up to 15 minutes of juggling speed and altitude before the leading edge slats could finally be retracted. I cannot remember the water tank figures or the takeoff weight benefit, unfortunately. Strangely, I can remember the fuel quantities even now: full wings 13680 kgs, full wings plus centre tank 21809kgs, wings plus centre plus fin tank 23040kgs. The T2 was a very nice aeroplane, but not as fast as the earlier T1.

[LAS1997]

If you want any information on the Trident contact Kevin Bowen at the Heathrow Trident Collection. Email [email protected]

[Gripper123]

Thank you

I'm astonished and uplifted by the astonishing amount of interest aroused by this potentially 'damp' topic. Since my original enquiry - a kind, erstwhile colleague has lent me his Trident manuals which; up until then, had been an integral part of his loft insulation.

Reading the manuals without the impending threat of a sim-check was 'quite' interesting. However they did not cover the whole story, or answer all my questions. That surprised me as I had always believed the gaps in my knowledge to be self inflicted.

Nevertheless here are the snippets of information, and for the truly anal; references of where they can be found.

• Taxying checks item 15) Water injection master switch ... off (Ops manual Vol 1 Drills 2)
• Weights MTOW ...65,320 Kg. MTOW injection water added...65,770 Kg i.e. 450 KG increase. (Ops Vol 1 Flight Management - Handling Limitations (a).
• FAILURE OF UNUSED INJECTION WATER TO DRAIN. Symptom: Contents gauge not reading empty. Action: .1) Injection Water Master Switch....Drain. 2) If remaining water does not drain, reselect master switch to prime and open any throttle to TO posn switch for a short time. 3) f remaining water does not drain, revise flight plan and keep below freezing level. This seems to confirm that the H2O was demineralised water not water meth. (Ops F.M. Fuel 3&4)
• All further references are from (Ops Technical)
• (Fuel 10 & 14) Servicing points....Water injection filling point (pressure connection) adjacent to rear equipment bay door. Provides for pressure filling the injection water system at a rate of 50 gal/min. The capacity of the tank is 145 imp. gallons.
• Ditto : Injection water drain valve test button...... Provides a test on the ground that the pump and drain valve are not frozen. When pressed the drain valve should open and a full flow of water should drain from the outlet.
• (Engines 7) SPEY 512 TO perf. sea level dry......12,600 lb thrust until 23 degrees C. My copy of a R.R. book: "The Jet Engine" promises an extra 7 degrees of max thrust if water is used and this is the real benefit of water injection (if it works).
• Lastly, (Loading 1) The TO weight can only exceed 65,320 Kg if the excess is in the form of injection water. The max quantity of injection water is 145 imp. gallons (658 Kg).

I hope that will either be of interest or help you travel to the land of nod.
Anyways it will help my quest for accuracy and authenticity in the book. So be warned your aircraft VC 10; Vanguard; Viscount; Comet; Concorde; Britannia; may be next.
Happy landings!

[kenparry]

So, you uplift 658 kg of water to give an increase of 450 kg in MTOW. It seems the solution is worse than the original problem. Or am I missing something?

[DaveReidUK]

Originally Posted by kenparry

So, you uplift 658 kg of water to give an increase of 450 kg in MTOW. It seems the solution is worse than the original problem. Or am I missing something?

It makes a WAT limitation less limiting.

[Gripper123]

WATs app

Yes on the face of it the figures seem contradictory but remember that in very high ambient temperatures, on short or limiting runways and at high altitude airports the Trident was unlikely to be able to lift MTOW anyway. So the extra 4% or so of thrust was reflected by the increase of the limiting (wet) take off weight compared to the dry limiting take off weight.

In practice that was enough to lift the water and a bit more payload if the system worked. In practice it often didn't and in my book I want to describe how we had to return to stand, drain the unused water and; not only offload the few extra passengers we thought we could carry, but also a few more. Because the air temperature had increased whilst we'd been farting around with a system that wouldn't have been necessary, if BEA had let DeHavilland build the aircraft they designed in the first instance viz. the Airco 121 with Medway engines alias the Boeing 727 but that's another story!
PS The 658 Kg of water was soon dissipated (if the system worked) as was the resultant extra 4% of thrust. Then the fun really started.

[blind pew]

Wat

Always wondered about the truth of our performance calculations wrt the real world. At tel Aviv we had to cross the beach above 1,000ft which we often didn't make by quite a lot. Iirc the military had spotted aircraft flying along it. Our data was based on Stephenson screen readings ..no allowance for the air over hot concrete or tarmac and no soundings.
Did see one skipper descend to get the droop in. Once at Nicky suggested to another that we should firewall the throttles..P3 had a better view..he looked up..then in ..then at me and said don't worry ACE...but it was close.

[rog747]

correct me if i am wrong speys had de-min water and Darts had water-meth?

[DaveReidUK]

Originally Posted by rog747

correct me if i am wrong speys had de-min water and Darts had water-meth?

Yes, as per post #10.

[Georgeablelovehowindia]

Originally Posted by rog747

correct me if i am wrong speys had de-min water and Darts had water-meth?

As a sometime Dart Herald pilot, I can confirm that water meth is correct. I can also confirm it was de-min water for the Spey. On the One-Eleven, as operated by Monarch Airlines, it was wobble pumped out of blue barrels on turn round at outstations by one or other of the flightdeck crew. We used to view this interesting - and perspiring - procedure from our 737-200 Adv with JT8D-17 engines.

Came the day at Menorca when the company One-Eleven captain arrived on our aircraft and commanded me not to go anywhere soon as he had a problem. (As he happened to be the Deputy Flight Ops Director at the time, I thought I'd better do as commanded.) The water injection had failed out of Luton and now they couldn't get back without tech-stopping. How much of their baggage could we take, to help them out? Before I could stop him, my tourettes-prone first officer chimed in with "All of it, probably." (Ouch!) In the end, I think we took half - about 700 kg, which got them home without tech-stopping.

[WHBM]

Originally Posted by Georgeablelovehowindia

it was wobble pumped out of blue barrels on turn round at outstations by one or other of the flightdeck crew.

Likely a procedure following the Paninternational accident, referred to above, where an outstation ground crew had got fuel in the demin-labelled barrels. There was presumably a test of the contents as well, first.

Surprising a One-Eleven could not get from Mahon to Luton without a takeoff aid. Freddie Laker used to run them from Gatwick to Tenerife and back, and I think his -300 variant did not have the water aid.

[kenparry]

Always wondered about the truth of our performance calculations wrt the real world.

In my long-gone B737-200 days, I sometimes flew with a colleague who had been on the Trident with BA. He said, with some feeling, that the Trident in hot weather could either turn or climb, but not both, with all 3 Speys working as advertised. It seems you are not the only one who had doubts about meeting the performance requirements.

[Brookmans Park]

De Min

In my1-11experience it was unusual to have to pump the water as most regular destinations had a little bowser towed by the fueler
If we had to pump it from drums we had pump which was powered from the pneumatic system

[Discorde]

Originally Posted by kenparry

In my long-gone B737-200 days, I sometimes flew with a colleague who had been on the Trident with BA. He said, with some feeling, that the Trident in hot weather could either turn or climb, but not both, with all 3 Speys working as advertised. It seems you are not the only one who had doubts about meeting the performance requirements.

Here's a comment I posted a few years ago on a thread about Trident performance:

The T3 was a 5-engined airliner of three different engine types . . . Spey (A RR device for turning kerosene directly into smoke and noise, with a bit of residual thrust), Boost & APU . . . so three different sets of limits to learn for the ARB.

We used the boost once every 8 or 10 take-offs. Its unreliability was notorious. I recall doing ATH to LHR in a T3 with a u/s boost on a hot summer's day (remember those?). Boostless, we couldn't lift the required fuel so had to tech stop GVA - highly embarrassing. And a winter OSL to LHR off a slushy runway. Full load of pax but no prob using the boost & contaminated runway perf. Fire up boost just before entering runway. It works! Blip switch from ground idle to flight idle - still working! Capt opens up Speys - and boost promptly dies. Back to the terminal. Eng sucks his teeth. 'Nah, can't do anything here, boys - you'll have to take it home boostless'. Rework contam rwy perf - we can take 40 pax. Luckily the cull had to be done by the ground staff rather than us. So we guiltily left behind approx 100 pissed-off pax.

Once shut down in flight the boost could not be relit . . . which led indirectly to the famous Malaga incident - the guys shut down the boost at 6k on climbout (SOP) after which one of the Speys gave up the ghost, so they diverted to MAD. Instructed by ATC to go around on short final the Tripod wouldn't climb with 1½ of its 3½ donks dead & flew a very low level cct before successfully landing off the next approach. Turned out they were operating outside the WAT limit, although there was no way they could have known that at the time.

Anonymous broadcast (apocryphal) from someone on LHR Tower freq as a T-bird lines up on 28R: 'You're about to witness De Havilland's attempt at the world ground speed record.'

[dixi188]

Basically the RR Dart power was augmented by the use of Water/Methanol. The Water cooled the air and the Methanol provided the extra power.

In the RR Spey the Demin Water cooled the air and the Fuel Flow Regulator (CASC) provided extra fuel to provide the extra power.

[JW411]

Well, I am getting a bit ancient but I thought the water provided the boost and the methanol stopped the water from freezing?