Is water injection a redundant technology?

[splitbrain]

Apologies for going over an old subject, couldn't find a suitable old thread to resurrect that wasn't closed.

I'm doing some work on a course manual which must include water injection systems but, whilst I understand how they work, am beginning to question the relevance of the subject (as a thrust augmentation mechanism) to todays aircraft. I know the Harrier has a water injection system but understand that later evolutions of the Pegasus are sufficiently powerful as to be able to operate without water injection at all.

So, does anything still use water injection, or water/meth injection as a thrust recovery/augmentation system or am I simply recounting history.

Many thanks

[DKP1]

Even the latest mark of Pegasus (Mk 107) fitted to the Harrier GR7 and will be fitted to the GR9 has Water Injection and uses it!

[Rigga]

Opening myself up for more criticism - I believe the Fokker F27 still uses Water Injection too - Water tank is up in an engine nacelle (- Not to be confused with the fairly similar looking F50, mind!)

[Jackonicko]

Don't the B-52 and some KC-135s still rely on water injection, too?

[A and C]

Rigga you are correct the F27 has water injection.

[hobie]

Doesn't the B-52 and some KC-135s still rely on water injection, too?

http://answers.yahoo.com/question/index?qid=20061007085218AAMuU7p


[quote]The J-57 engine used on older B52s and KC-135 tankers both used water injection for takeoff. The concept was the same as in the piston engines; it lowers peak combustion temperatures. In a turbine engine, this allows you to kick up the fuel delivery rates for more power during takeoff without the risk of going over-temp in the turbine section.


Source(s):
Former AF "SAC Trained Killer", working in aircraft maintenance.

[splitbrain]

Thanks guys,

With respect to turbojets I think the key phrase is 'used to be used on'. Other than the Harrier, I cannot find another current application of water injection in a jet, although some props do still seem to have it.

[Rigga]

Those "Props" have Jet engines too, and use water in exactly the same way as High-Bypass Turbofans, for Hot, High or Heavy performance enhancement. (Does that sound too "Engineery"?)

[LateArmLive]

Water injection is still used daily on the Pegasus engine, but purely to cool the engine, not to increase thrust in the same way that other water injection systems operate.
Hope this helps.

[om15]

Although the Dart is not a modern engine there are still a few around, the injection is a water methonol system for use during take off.
The mixture is water 63 per cent, methonol 37 per cent plus Pyrodine at 0.5 % by weight, ( usually purchased ready mixed)
The system can be a power restoration system, (F27), where by the power is increased to the rated take off power, or boosted (Herald) where the power is inceased from a "dry" torque to a "wet" torque. This is achieved by simple adjustments to the water meth control unit, and these are set during the engine installation process.
The mixture increased the air density and adds more fuel, the aircraft that operated at max take off weight ie freight operators, tended to use water meth every time.

Regards,
om15.

[splitbrain]

Those "Props" have Jet engines too, and use water in exactly the same way as High-Bypass Turbofans, for Hot, High or Heavy performance enhancement. (Does that sound too "Engineery"?)

Thanks rigga,

Yep, i realise that a turboprop is a torque producing gas turbine and that water injection can be used in the same way is it is/was on a jet.
It does seem though that, Harrier aside (which I used to teach as a propulstion instructor on the Harrier Maintenance School; GR3 and T4 vintage :\ ) water injection now only appears on some older turboprops although it may have a use as an omissions reducing method.

[Delta Hotel]

Latearmlive,
Water injection does cool the Mk107 engine in high temps, which then allows you to pump in more fuel to gain more thrust!;)

[stevef]

Drifting off topic slightly, I seem to remember the DC6 (P&W R2800) used an Anti-Detonation Injection fluid that included a small percentage of fish oil to keep the valve gear/guides and piston rings adequately lubricated.

The leaky engines then kept the airframe lubricated.

[bvcu]

Dont forget the Andover !! Believe a couple still flying from a very long runway in wiltshire !!!! I believe some of the early 747 - 100 's with P&W JT 9'S but deleted a long time ago .

[GOLF_BRAVO_ZULU]

The mixture is water 63 per cent, methonol 37 per cent plus Pyrodine at 0.5 % by weight, ( usually purchased ready mixed)


I'm surprised that pyridine (used as a denaturant to deter people from drinking the alcohol) is allowed in methanol for gas turbine use. I recall reading (can't remember where) that it is harmful to hot nickel alloys.

DEF STAN 01-5 ( http://www.dstan.mod.uk/ ) makes no allowance for it in AL-14 (Methanol) nor AL-28 (Water Methanol 44/56); and both specify "colourless"

[Jehu]

Used to fly a civil BAC111 (500 series) which had water injection. Very useful for getting airborne from Naples with a full charter pax load on a stinking hot day. I don't know where the aircraft is operating now, if at all. RR Spey engines IIRC.

[LateArmLive]

Latearmlive,
Water injection does cool the Mk107 engine in high temps, which then allows you to pump in more fuel to gain more thrust!;)

True, what I was getting at was that it is not the water that increases the thrust (by increasing the mass flow rate), but the cooling effect it brings that allows (as you say) the engine to run hotter/faster.
You can get the same thrust without using water (as I'm sure you know) but the engine life would be rapidly reduced!:O
Cheers
LAL

[om15]

Golf Bravo Zulu,
regarding the pyridine ( please excuse original spelling) additive to the water meth mix, this info originated from a Handley Page Maintenance Manual circa 1970's. The mixture came in 50 gallon drums ready mixed, so I have no experience of the contents. There are a couple of spec.references that I have come across, RR Spec MSRR9859 and D Eng RD2491, but as yet I haven't found the documents.
Any boffins out there with the answer?
Regards
om15

[GreenKnight121]

So, getting back to the original question... leaving old designs still in use (Pegasus, TF-33, etc.) aside, do any turbojet/turbofan engines designed since ~1970 use water injection? :rolleyes:

This includes F-100-PW, F101/110-GE, RB.199, etc., but not new versions of old engines.

How about those designed since ~1985?

[forget]

9/06/1971 Pan International. BAC-111 Hasloh, Germany The aircraft collided with a bridge, shearing off both wings, after a double engine failure occurred during takeoff. The water-injection system to cool the engines during takeoff was inadvertently filled with kerosene instead of water.

[MrBernoulli]

Modern fan engines (High Bypass) just don't need it. Water injection (or water/meth) was required to boost and cool older turbojets. As a subject for MODERN jets, it has no relevance.

[Mel Effluent]

The LET 410UVP uses the Walter M601E engine which has water injection. Link to website here:

http://www.walter.cz/htmlen/ramen.htm


Mel

[Art Field]

As an indication of the effect water/meth had on the engines of that era, the Avons [200 series IIRC] fitted to the tanker version of the Valiant, gained an extra 1000lbs of thrust, moving them up from 10,000lbs to 11,000lbs. This sometimes moved Stop and Go back to the right side of each other, not always the case in those early days.

[Solid Rust Twotter]

Convair 540 uses Allison 601D-21s with water meth injection. Same ratio as the Darts I think. Atlantique uses it too IIRC.

[Hockham Admiral]

:) The Tyne turboprops in the Belfast uses water meth in temperatures above ISA to maintain the rated SHP. It works up to 31Deg C and then the power falls off quite dramatically! We used it almost all the time for hot/high fields and always if we used 10deg flap for max perfomance.

[splitbrain]

:) The Tyne turboprops in the Belfast ....

Shouldn't that be BelSLOW. ;)

[GlosMikeP]

There's a degree of confusion crept in on the thread. Water injection can be with or without methanol added.

First of all, there is no value using water to cool a jet engine. You can't carry enough of it and it would be counter-productive anyway to have super-heated steam chasing around the airframe rapidly corroding everything in sight.

The value comes in cooling the inflow air, thereby increasing its density, which means a greater burn can be sustained, which generates more power.

The difference in temperature between in and out can be used to measure thermal efficiency; the greater the temperature difference front and rear, the higher the efficiency. So at sea level - and relatively high inlet temperatures therefore - water cooling the air means it's at a temperature of several thousand feet higher, but with the density advantage of the lower level. Result = bigger bang (or in fact, higher volume of jet efflux available for generating thrust).

Methanol adds an anti-freeze effect to the water, so enabling even lower inlet temperatures to be achieved and with obvious advantageous consequences over straight water. However, it's also highly combustible, so adds to the fuel and burning properties as well.

It doesn't matter whether it's a high or low by-pass jet, turbojet or turboprop; the principles are the same. However the water/meth is usually (but not always) sprayed into the compressor stages. Clearly on a high bypass, that means NOT the big fan at the front, but the teeny-weeny stages that actually form the front-end of the hot core that drive the fan.

I am not aware of any physical, engineering or other reason why water-meth shouldn't be used on any jet or piston engine, provided it's not used where it would cause the engine to burn out or over-power. It's a perfectly valid way of overcoming the Weight-Altitude-Temperature (WAT) limit.

[Hilife]

Splitbrain

As you have observed, in days of old engine manufacturers utilised Water/Water Methanol Injection to increase mass air flow through the engine when higher ambient temperatures resulted in reduced ITT/EGT margins.

Although these systems overcame the problem to some degree, they came with additional penalties such as weight (fluids & system components), additional component maintenance -not to mention the risks associated with the carriage of methanol.

As a result of substantial improvements in hot section material technology and cooling efficiencies, modern gas turbine engines are capable of producing the same amount of SHP/Thrust but at greatly increased ambient temperatures without the need for weighty and sometimes dangerous boost systems and therefore provide increased efficiencies and safety for the operators and crew/passengers alike.

Hope this helps?

[splitbrain]

First of all, there is no value using water to cool a jet engine. You can't carry enough of it and it would be counter-productive anyway to have super-heated steam chasing around the airframe rapidly corroding everything in sight.

Mike, I don't believe anyone is suggesting cooling the engine externally, if this is what you mean. The Harrier system does work by injecting water into the combustion chamber and turbine inlet flow; this has the effect of cooling the exhaust gas flow permitting the addition of more fuel to allow the engine to spin faster and therefore develop more thrust. Arming the water injection system in the cockpit has the effect of rasing the JPT and RPM datums to their 'wet' values.

Hilife, thanks for your input. You summarise what I'd more or less concluded myself, that material, design and technology advances have more or less made water injection redundant on the latest engine variants.

Thank you all.

[GlosMikeP]

Yes, I'd agree with Hilife too. Thought it would add an unnecessary complication to my post, so thank you for bringing it out. All that luggage and maintenance is a pain if you don't really need it. There might still be a case for the hot/hi though, especially military jets operating at edges of envelope.

And you're right, I did interpreted the previous post as for some form of jacket or external spraying.

Re the injection into the combustion chamber, IIRC that's the preferred method for a more conventional axial flow jet, because it gets a more even distribution through the mixture and because it's possible to pump a lot more in, faster and more effectively. I went for the soft option to illustrate. I should have known better than to over-simplify on PPRuNe!!

Nevertheless, I think you may still be referring to the cooling effect on the inlet air to the combustion chamber (laws of thermodynamics and physics will do it anyway), though, rather than other cooling effects. I can see a case for cooling the turbine though (as opposed to inlet).

The only other possibility I can see - but I think it unlikely- is to use the water to improve the boundary layer around the combustion chamber, so that higher temps can be maintained in the burn.

I'm a bit sceptical because it would probably have been easier to design the larger boundary layer with inflow air from the start rather than augment it in some way. But if there's a RR designer watching, by all means pronounce me wrong (but put us all out of our misery with the answer too please!).

[Art Field]

Going back 40 years puts a strain on the old memory cells but I am fairly certain that the effect on the Avon of water/meth injection was to increase the max RPM at the limiting JPT. The throttles were fully advanced and the RPM in dry power was automatically limited to the max JPT. On selecting water/meth the RPM increased by some 2 to 3 % with the JPT remaining the same, a noticeable increase in thrust and significantly for stream take-offs, a much smokier exhaust. Certainly in that application the cooling of the turbine would seem to have been the raisin d'etre.

[GlosMikeP]

Going back 40 years puts a strain on the old memory cells but I am fairly certain that the effect on the Avon of water/meth injection was to increase the max RPM at the limiting JPT. The throttles were fully advanced and the RPM in dry power was automatically limited to the max JPT. On selecting water/meth the RPM increased by some 2 to 3 % with the JPT remaining the same, a noticeable increase in thrust and significantly for stream take-offs, a much smokier exhaust. Certainly in that application the cooling of the turbine would seem to have been the raisin d'etre.
Seems consistent with earlier posts. Certainly you'd have got the extra boost for putting the mix in the front end. Might the turbine have had simply water thrown at it by leakage from the leading edges of the blades, to form a blanket boundary layer? I suspect there's a bit more going on besides this but I can't guess at the stoichiometrics and thermodynamics.

[superchuckles]

actually, water injection only slightly increased the RPM's -- almost negligibly. I was a crew chief on KC-135A's at Castle AFB back in the early 80's. On a turbojet engine, water injection cooled the inlet charge, made the air denser, & therefor had more potential for expansion. was similar in practice to hitting afterburner. depended on the ambient air temperature more than anything else as to it's effectiveness. if it was 110 degrees out, & you had a heavy fuel load, you probably wouldn't have enough runway to get off the ground without water. the new CFM56 engines made it all a moot point though, quieter, more efficient, & about twice the thrust of the old J57's. The BUFF's still use the J57's btw.

[stilton]

I thought all remaining B52's are H models with turbofans ?

[obnoxio f*ckwit]

And most of them are nearly as old as this thread!

[Basil]

Military Argosy (RR Dart engines) approach to El Adem one afternoon - couple of little misunderstandings led to being above water-meth cut-in RPM when Flt Eng switched WM pumps on in landing checklist.. .Quite dramatic moment as VP props tried to cope with sudden but initially unstable injection of additional push-juice! :ooh:

[PDR1]

This question used to come up a couple of times a year in the office, and so I was given "custodiamship" of the following "standard answer" which came from a friend who was (and still is) a gas-turbine designer at RR. I've posted it before, and I know some people disagree with it, but I go with Gav's version - YMMV:

The following is a standard answer that was prepared by one of the gas turbine design specialists at RR:

Are you sitting comfortably? Good, then we shall begin ....

First of all, gas turbine water injection is a thrust augmentation device. The concept of injecting water into a gas turbine has got sod all to do with cooling the engine as one of the advantages of a gas turbine is that they are self cooling – ponder the extensive use of such beasts in stationary applications, such as on oil rigs, pipelines and for powering ships.

Now we’ve got that one nailed – just how can you increase an engine’s thrust by injecting water? At first glance, it seems an absurd thing to do. Well, it’s simple really, and there are three different ways of doing it:

1) Add the water at the front of the compressor
2) Add the water directly to the combustion chamber
3) Add the water immediately before the turbine section or just before the propelling nozzle.

Taking each one in turn:

1) Injecting water at the compressor face has the effect of lowering the temperature of the inlet air, (assuming the water is at a lower temp than the ambient temp, of course, but seeing as you will generally be using water injection on hot days, that's taken as read). Remember the old maxim of 'It's fookin' difficult to compress cold air and vladimir impossible to compress hot air' and you soon realise that lowering the inlet air temp allows you to get either:
a) the same level of pressure rise as before but from less power offtake or
b) more pressure increase for the same shaft power requirement.
Both of these effects give you greater thrust (via less power offtake or through higher pressure ratio respectively) but option 1b) is usually the one used. In a nutshell, you are fooling the engine into thinking the ambient temperature has suddenly gone down and gas turbines work best at low temperatures. Because you have lowered the inlet air temp then obviously you are lowering the compressor outlet temp as well. This allows you to add more fuel and gives you a greater delta t across the combustor. You are also putting more mass flow through your engine (because you've added the water and water is more dense than air), giving you greater thrust because thrust is directly related to mass flow. Additionally, you can utilise a water/ethanol mix if you so desire, with the ethanol being burnt in the combustor giving you even more bang.

From point 1b) you can see the problems that occur with gas turbines at high ambient air temperatures: Higher air temp = lower compressor efficiency = lower pressure ratio = less efficient combustion = lower resultant thrust because the turbine is using up all the available power to run the compressor = you ain't going nowhere.

2) Adding water directly to the combustion chamber is one for the theoretical physicists. What you are trying to do is induce blockage and temporarily reduce the volume of the chamber, thus increasing the pressure inside the combustion chamber as the efficiency of the combustion process is increased at higher pressure. It also has some other peculiar effects such as increasing the air flow speed which is not detrimental. This type isn't used much as it's difficult to model and understand and can lead to combustion instability, which is a bit of a bad thing (tm)

3) Adding water at the turbine face or just before the nozzle simply works by adding mass flow to the engine's exhaust thus giving you more stuff out the back = greater thrust.

Option 3 is the simplest and most straightforward whereas option 1b will most probably give you the greatest thrust increase. Sometimes you will get a water injection installation that gives you both compressor and nozzle injection to get even more increase at the expense of plumbing complexity.

If anybody ever says that water injection is for 'cooling the engine', just ask them exactly what a couple of gallons of water is supposed to do to a raging inferno at 1,200 degrees centigrade travelling at 200 meters per second. You should get a few blank faces in return...


€0.07 supplied,

PDR

[Mozella]

Following my stint in the U.S. Navy flying the F-8 Crusader, I went to work for Trans World Airlines as a pilot, starting out in the flight engineer seat on the B-707. TWA had all sorts of 707 models, but one was powered by the same turbojet engine used in the F-8, the famous J-57, called a JT3C in civilian life. It's been a long long time, but if I remember correctly the "straight pipe" (non fan) versions injected demineralized water (no other additives) into the combustion chamber for about 2 minutes on take off to increase the mass flow through the engine.

Anyone who's flown a non-fan jet knows about the poor static thrust produced by pure turbojets engines, which is why they invented fan engines in the first place. But in the mean time, water injection allowed heavy take offs to be made with conventional turbo jet powered airliners. The dry thrust was just over 11,000 pounds and "wet" it made about 13,000 pounds.

Unfortunately what's left of my brain can't remember how much water we held nor do I recall how fast we pumped it, but I do remember being impressed when they taught those two facts in ground school.

Any water not used prior to thrust reduction following take off was immediately dumped.

I also seem to recall that the pumps were powered by two electrical busses, one for engines 1 & 2 and another for 2 & 4. The FE's job was to protect this part of the electrical system at all cost during take off because losing one meant a huge reduction of thrust on one side. Why Boeing, who was and still is famous for their good engineering practices, wired it that way I'll never know. Anyhow it was an interesting system and a hot weather, heavy take off in an old water wagon was always a thrill.

Once in cruise, these aircraft were fast primarily because the non-fan engines were so slim.

[IcePaq]

Since this topic is in "military aviation", I'm assuming at least one military jet used water injection to combat high inlet temperatures for high speed flying.

[PDR1]

I doubt it. I can't be certain, but where used in jets it would almopst always be for thrust at low speeds rather than high-speeds.

Some *piston* engines used water or alcohol/water injection for high-speed flying, but they were using it to allow higher boost pressures without knocking (which is not a feature in jets).

PDR

[OK465]

The F-105 (J-75) had a water injection system. Its sole purpose was to increase takeoff thrust and any residual water was dumped after takeoff. Had nothing to do with high speed flight, of which the aircraft was reasonably capable.

However, takeoff rolls were generally pretty long regardless.

edit: To be accurate, you could feel it when the water 'kicked' in, but it was more like a nudge than a kick.

[Mechta]

OK465, Why is the surplus water dumped rather than being fed into the engine until it is used up?

[MightyGem]

Since this topic is in "military aviation", I'm assuming at least one military jet used water injection to combat high inlet temperatures for high speed flying.
The Harrier(AV8B) used it in the hover.

[OK465]

Mechta,

It's been awhile and my books are stashed away with the black widows in the attic, but I believe the water switch, which was just forward of the throttle was only enabled with the AB engaged. So when AB was disengaged the water was terminated anyway. Only used it a couple of times just to check the system was still functional. And in fact the water might have been used up prior to AB termination under some circumstances but you couldn't be sure.

The long toggle switch was a 3 position, On, Off, & Dump to both clear and prevent the plumbling and container from icing up at altitude and get rid of the minimal residual sloshy weight I suppose. I don't remember the capacity.

There's a notable incident of an F-105G tail section being blown off on the runway at the old George AFB because the wrong fluid was substituted for water. :eek:

[Rosevidney1]

OK465: I think you may be underselling the Thud with faint praise!
Had nothing to do with high speed flight, of which the aircraft was reasonably capable.
Surely it was one of the fastest military aircraft at low level?

[Saint Jack]

Helicopters too, early models of the Bell JetRanger, the 206A powered by an Allison 250C-17 were available with a water-methanol injection system as an option.

[Ascend Charlie]

We had a B206-L, the basic model with a C20 engine. It had a water-meth tank and we used "squirt" on takeoff , or sometimes just to hover on a hot day in Oz. Its use immediately pulled down the TOT, and allowed us to pull more power. Had to be turned off by 60kt, but by then we are well into translational flight.

Usually not needed for landing, as we had burned off enough fuel to be able to hover in TOT limits.

[IcePaq]

I'm fully aware of the piston engine usage of meth/water injection systems as I design and use them on speed record cars and would love the chance to take a shot at bringing the reno race crowd up to the current century technology but they all state "cash is a problem" so we likely won't see digital fuel injection on an unlimited for quite a while.

This jet used water injection to keep temps down but I don't see any "factory stock" military planes using it for the same reason as other water injected jets.

http://www.916-starfighter.de/916starfighter/world/large/104wRB.jpg

[ericferret]

At least one UK 206L had the system as I fitted it and removed it more than once.
Tank was on the forward wall of the baggage bay.
Always amused me that it needed water meth in the UK.

[megan]

Germans used nitrous oxide along with water meth. Some PR Spits and NF Mosquitos were fitted with nitrous also, 250 BHP increase per engine on the Mossie.

[tonytales]

Pratt and Whitney R-2800 and R-4360 used a 50-50 mix of water-methanol alcohol for ADI. At my company (Lockheed Aircraft Service) at Idlewild (later JFK) we bought it pre-mixed in 55-gallon drums. Someone in previous post said fish oil was added and may have been but our mix used Dromus oil. It is water-soluble oil usually used as a cutting fluid in machine shops. .
Flying Tiger at their Idlewild base apparently mixed their own ADI locally. One day the person making up the mix used deicing glycol instead of methyl alcohol. The first Tiger's DC-6A freighter getting this mix took off from Idlewild to the tune of backfiring. They lost further power and made a smooth landing on a mud flat in Jamaica Bay off the airport. The plane was partially immersed at high tide but it was retrieved, taken to Lockheed Air Service and repaired and returned to service.
Apparently, in WW-II the P-47 (R-2800) were modified for ADI use but had poor results. The Pratt and Whitney service representative found they were using ethanol alcohol and apparently it doesn't work. A switch to methanol fixed the problem.

[riff_raff]

The P&W R-2800 typically used around 10 lbs/min of ADI at TO power levels. The ADI was various combinations of water, methanol, ethanol, and a little bit of anti-corrosion oil. Each engine ADI tank held around 15 gallons. The fuel flow had to be adjusted based on the ADI mixture. Water does not contribute energy to the combustion process, and it displaces available oxygen in the intake charge mass flow, so the fuel mixture needs to be adjusted accordingly. Methanol and ethanol in the ADI does contribute energy to the combustion process, so the fuel mixture also requires adjustment to compensate for this.

[Fareastdriver]

To expand on Art Field's post #32. The Vaiant used water meth for take off only.

When initiated it increased the RPM by 300 from 8,000 to 8,300 with a constant JPT adding an extra 1,000 lbs. thrust to each engine..

The water meth tank was in the rear of the fuselage, held 1410 lbs. of W/M and lasted for one minute.

Precisely at the time the mainwheels left the runway at Nairobi International.

[galaxy flyer]

Yes, the present fleet of BUFFs are TF-33 powered, the J57 is gone everywhere. The KC-135s were the last J57-powered planes and they've been gone for two decades.

Republic, build a runway around the equator, we'll design a plane needing it for take-off". Only the C-5 needed more runway. A 1 minute roll and a run of 11,800' at LETO once.

GF

[megan]

Gulp GF. Folks always talk about the IL-76 take off at Canberra as an example of using it all, but think this more impressive.

RYVsotySupE

[Traffic_Is_Er_Was]

Impressive, and contributed to the local economy by resulting employment of hundreds to sweep countryside off the runway.

Is it the Metro's fitted with the Garrets that also use water-meth?

[RHKAAF]

When I did the MK1 Andover course in the 1960's, we were told the watermeth system was only to be used when absolutely necessary because of weight, temperature or altitude considerations. I think most of us used it a lot of the time for the extra thrust it gave on take-off and initial climb, but never on a check ride unless we could absolutely prove it was necessary.

[Lyneham Lad]

Gulp GF. Folks always talk about the IL-76 take off at Canberra as an example of using it all, but think this more impressive.

RYVsotySupE

Presumably that was filmed in slo-mo... ;)

[seafury45]

Traffic #56

Yes, Garrett, now Honeywell, TPE331 on Metros and Jetstream use water/meth in summer in Australia. It is a 45% mix. I cannot remember the capacity or the usage rates for the Metro III but we used about 4 x 205 litre drums each summer.