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Water injection?

Old 16th Nov 2022, 11:45
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Originally Posted by Anilv View Post
Last encountered them when I did a loadsheet course for SAA around the late 80s I think. It was explained that there was big tank which would be emptied during the take off. Tank was in the wingbox area as had an open top as a closed tank would not allow the pumps to flow as fast. I seem to remember the figure of 3000kgs added if water injection was used but it was a long time ago.

Anilv
From an aged memory at SAA in the 70s the B707B/C was 334000 lbs dry, 336000 lbs wet max take off so 2000 lbs water? Good for about 2 mins
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Old 16th Nov 2022, 12:16
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Had water-meth injection on a Jet Ranger I flew in the Middle East - gosh - nearly 50 yers ago. Some days I reckon we could have used more water-meth than fuel.............
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Old 16th Nov 2022, 12:39
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Originally Posted by Quietplease View Post
All water injection did for a BAC1-11 was make it noisier. No discernible effect on performance.
IIRC the water injection gave another 500lbs of thrust below 25C and restored thrust when hotter up to about 40C.
Used on most take offs in Oman.
I remember going out of Tehran in 1979, (me on jumpseat), the water ran out as we hit the inversion layer. The aircraft stopped climbing until we got a good distance from the city. The Captain wrote in the F700, (tech log), Max Continuous Thrust used for 17 mins. The answer "Noted with thanks".
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Old 16th Nov 2022, 17:45
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There's an interesting photo of an Emerald Airways HS748 (G-ATMJ) with an engine on fire during ground runs. The rumour was that waste Avtur had been drained into a water meth drum at some time and later unknowingly decanted into the aircraft's water meth tank.
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Old 16th Nov 2022, 20:06
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When a 1-11 took off without using water, it was like a 'Smokey Joe', trailing smoke into the distance.
When it used water, there was no smoke, just extra noise.
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Old 17th Nov 2022, 00:18
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Monarch and Dan-Air ended up with a fairly major logistical operation to make sure barrels of de-min water were properly marked and positioned at airports around the network where they were required for the performance enhancement. The marking of the barrels was much clearer after the Paninternational accident mentioned earlier, when the de-min water tanks were accidentally filled with JetA1 with dire consequences.

Hand-pumping the stuff into the aircraft was generally the F/O's job on turnround unless you could "induce" a rampie into doing it. Unless I'm much mistaken, the BA 1-11-510EDs didn't have the capability and it fell into disuse during the latter days of the type's service even on the 517FE and 518FG aircraft with Dan-Air and British World, and the ex-BCAL aircraft that ended up with European Air Charter via BA.

I do recall standing not too far behind a Tarom 1-11 operating for Adria Airways in about 1985 and getting a little bit wet as the water at the very beginning of the take-off roll was simply ejected downwards and backwards from the aircraft onto a pathway below the runway. The "extra noise" probably explains why I'm having increasingly frequent arguments nowadays with the other half about being a deaf old git...
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Old 17th Nov 2022, 05:02
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I believe the Jetstream 31 also used water methanol when necessary
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Old 17th Nov 2022, 05:37
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Originally Posted by ZFT View Post
From an aged memory at SAA in the 70s the B707B/C was 334000 lbs dry, 336000 lbs wet max take off so 2000 lbs water? Good for about 2 mins
Forgot to mention my experience was on a 747.

cheers!
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Old 17th Nov 2022, 06:24
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Originally Posted by Compass Call View Post
When a 1-11 took off without using water, it was like a 'Smokey Joe', trailing smoke into the distance.
When it used water, there was no smoke, just extra noise.
Other way round
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Old 17th Nov 2022, 07:34
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Just so the younger folk know what we are talking about, here's an AA 707 leaving LAX. It looks like they have raised the gear to clear the fence!



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Old 17th Nov 2022, 07:41
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Originally Posted by Anilv View Post
Forgot to mention my experience was on a 747.

cheers!
I had completely forgotten the SAA 747s initially operated with water injection.
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Old 17th Nov 2022, 08:35
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Water injection flow rates on the BAC 1-11.
The water tank held 110, (1100 lbs),imp gallons and this was used up in around 2 mins. so thats around 275 lb/min per engine. The take off fuel flow would be around 10000lb/hr which is 166lb/min. Therefore the water flow was a lot higher than the fuel flow. I always though this a bit incongruous.

Smokey engines. Am I right in thinking that JP4, (Wide Cut Gasolene), caused a lot more smoke than JET-A1, (Kerosene)?

Other aircraft with water/methanol injection include the early Shorts 3-30s with the PT6A-45A and B engines and anything with the RR Dart.

How can I remember all this stuff yet don't know what day of the week it is, I put the bins out on Monday instead of Tuesday.
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Old 17th Nov 2022, 12:08
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Ref #25

The conclusion was that it wasn't water meth in the water meth tank
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Old 17th Nov 2022, 16:05
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Flightrider

Unless I'm much mistaken, the BA 1-11-510EDs didn't have the capability
Thats correct - resulted in much fun trying to explain to various European ATC towers why we would be effectively orbiting during the departure to get to MSA before setting course!

PS How the heck has this triggered memories of all the power settings/call outs?
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Old 18th Nov 2022, 14:26
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Originally Posted by stilton View Post
I believe the Jetstream 31 also used water methanol when necessary
It did indeed. IIRC you could get three T/Os out of the tank if you used it sparingly.
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Old 18th Nov 2022, 16:50
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Originally Posted by ZFT View Post
I had completely forgotten the SAA 747s initially operated with water injection.
Yes the early S.A.A. B747's coming in and out of Heathrow were looked after by those of us on the BOAC, then B.A. Foreign Ops Team. We were often called to fix the Water injection System.
The P&W JT9D's needed a little help getting full power during hot or high Ops.
The Water Injection system had a Tank in the Dry Bay, forward of the Centre Fuel Tank. High-Capacity Electric Pumps were located in the L/H and R/H Inboard L/E Edge Area.
Tank was topped up to full with De-Min water. We had a Bowser at Heathrow specially for Demineralised Water. Probably left over from the B707's..
Water Injection was selected and armed from the F.E.'s Panel from memory and the system would run at full bore when initiated with the 3 phase Pumps activated by the Thrust Levers position, almost at T/O Power, until the Tanks were drained.
Water was introduced into the Compressor front end and would apparently increase the density of the air going through the Engine to give it a little power margin at hot or high Airfields.
The Crews we talked to said it helped a little but wasn't really that effective and was a tad unreliable.
I remember when we used to function the system after repairing it, the function would be noticeable with electrical power draw on the APU or GPU and you had to be careful with it.
Hope that helps...
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Old 18th Nov 2022, 17:53
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The Spey 512W fitted to the HS Trident 2E had water injection.
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Old 18th Nov 2022, 18:26
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And it generally ran out below 500ft..Tel Aviv we had to cross the coast above 1,000ft due to the military patrolling the beach watching out for terrorists.Of course it was rare to reach 1,000ft as we hit the inversion which put paid to a reasonable climb rate especially as we had the good old whip the flaps up at 90 seconds and reduce the power to Noise abatement setting which was below climb power.
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Old 18th Nov 2022, 22:12
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Originally Posted by wrecker View Post
The Spey 512W fitted to the HS Trident 2E had water injection.
Yes, on the Trident we only used water injection for take-off, 1st and 2nd segments so could use demineralised water, rather than water-methanol. One-Elevens could use water for Approach climb compliance so had to use methanol as anti-freeze to cope with the cold during cruise.
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Old 19th Nov 2022, 12:52
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Originally Posted by Allan Lupton View Post
Yes, on the Trident we only used water injection for take-off, 1st and 2nd segments so could use demineralised water, rather than water-methanol. One-Elevens could use water for Approach climb compliance so had to use methanol as anti-freeze to cope with the cold during cruise.
I don't remember any methanol on the 1-11. There was a mod. to heat the water tank so the water could be carried to destination. ISTR that without the heater the water had to be dumped after 1 hour to avoid freezing. The tank was at the front of the aft baggage hold so not exposed to extreme cold.
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