Water-Meth

[Torque]

Curious about this Water-Meth stuff. I understand it's pure Methanol mixed with water (as the name would imply)...what mix ratios are typical?? Is regular Tap water used or is it distilled Water or something??

[bigoil]

I heard a story where tap water or bottled warer was used on a LET410 and both engines had to be changed
distiled water required on these.

[om15]

Mixture used on RR Dart water meth injection was 63% demin water to 37% methanol plus prodyne 0.5% by weight, comes ready mixed.

BR om15

[Vortechs Jenerator]

funny when avtur is mistakenly put in water meth containers isn't it...I recall Emerald did it to a dart engine a few years ago:}

Quite a bang I believe

[Yoth]

Water meth used on the big piston engines too. Tap water is ok, meth just to stop the water freezing and some fish oil to lube the pumps and diaphragms ,etc.
R2800 radials on the DC-6 use it to boost take off power. Makes a top noise when 'full wet power' used.
RR Dart water meth is highly carconagenic. When I was with JEA on the F27's, it could only be topped up in Jersey, not on the mainland. Says a lot.

[om15]

http://s453.photobucket.com/albums/qq253/om15_2008/th_G-ATMU.jpg

G-ATMU at Ronaldsway April 2002 after it is alleged that the stbd water meth tank was topped up with Jet A1 from a water meth drum that had been used to drain fuel,

Fedex had a double engine burn out when both water meth tanks on a Fokker F27 were topped up with neat methanol,sometime in the early 1980s I think.

Bit of Human Factors involved,

BR om15

[Der absolute Hammer]

Yoth....

Is it not so that WM..at approximate ratio 70%W/30%M was stored in Jersey for Channex with the Electra?
Some British Dart airlines had strange ideas on WM. JEA never followed Fokker Manual on either trimming procedures or use of WM. WM selection consideration for Go Around was ignored. WM tanks held 30USG per side? Usual quantity carried in tanks in all circumstances was about 5USG? Bad news to run out of WM halfway through a wet operation!

[ZeBedie]

For the Dart, the book said water-meth "restored" t/o power when hot/high. But every time I used it, the torque gauges were bouncing off the stops - far more power than a cool day at sea level, or so it appeared. Can anyone explain?

[om15]

Depends on the installation, the Herald and HS748 were power boosted,(in general, depends on model) ie water meth injection gave a torque indication above isa dry power, the F27 (later series) was power restored, this to bring the power up to isa dry power when oat is above isa, water meth was not used to restore power lost due to altitude.
The injection system was pretty basic, the control was not exact, in practice the extra water meth induced power tended to surge above the dry torque setting on restored engines with a rise of RPM above 15000 and when run during ground runs both RPM and torque tended to return to settings quite quickly, during take off the prop would be coarsening and the watermeth control unit would be controlling with a slight lag, this causing a fluctuating torque.

BR om15

[camlobe]

On the old Shacklebomber, we were able to enjoy almost 500 hp increase per engine (from 1960 hp low gear sea-level rating, to 2450 hp high gear sea-level rating) by the use of water-methanol injection. Good stuff. To prevent 'over-fueling' the Rolls-Royce injector pump leaned off from 187 gallons/hour flow rate to 178 gallons/hour flow rate while each engine was injected with 18-22 pints-per-minute of water-meth. We used 60% demineralised water, 40% methanol (AL 24) as our mix. The methanol acted as an anti-freeze and fuel, while the water dramatically reduced the charge temperature by over 50 degrees celcius, thereby preventing detonation at the high boost pressure (of 81" mercury or 25 psi above atmospheric, and this design dated back to the '40's).

The first time I used water methanol was in an Argosy, and the torque gauges went all the way around! Very impressive.

camlobe

[smokin rivet]

I should be carefull putting it in my car i guess;)