Water Injection
Joined: Feb 2000
Posts: 116
Likes: 0
From: Montreal
The darts on the 748 use about 5gal/side/takeoff (of the water/meth) if it is used "conservatively". That is run "wet" until you clear the trees and then pull the power back to about 14500rpm to cut out the system. This leaves "wet" power still available if a fan quits.
Each engine has a tank in the aft wing root (a rubber tank which is a b!tch to change)which will hold about 30gal. Thus you only get 5 takeoffs max out of a fill-up (10 gal is min for dispatch). The water burns the hell out of the engines (high TGT's and torque) and costs a fortune, so many "bush" operators don't actually start burning it until well after the book says to.
It's really only used for well loaded takeoffs anyways.
On a side note there was the case of a 748 that got a full load of water/meth just before departing Churchill Man. quite a few years ago. The crew switched the water on to demonstrate the performance boost to a jumpseater or somesuch and blasted off. They got a huge boost and unbelievable performance. Through a couple hundred feet altitude both engines flamed out and they managed to safely land on the (fortunately) frozen river. It later turned out that an old water/meth drum had been filled with a witch's brew of waste oil/thinners/fuel, and the contents of that drum ended up in the tanks.
What a ride! They ended up towing the plane back up onto the airport on its own wheels and I believe it's still flying today.
Each engine has a tank in the aft wing root (a rubber tank which is a b!tch to change)which will hold about 30gal. Thus you only get 5 takeoffs max out of a fill-up (10 gal is min for dispatch). The water burns the hell out of the engines (high TGT's and torque) and costs a fortune, so many "bush" operators don't actually start burning it until well after the book says to.
It's really only used for well loaded takeoffs anyways.
On a side note there was the case of a 748 that got a full load of water/meth just before departing Churchill Man. quite a few years ago. The crew switched the water on to demonstrate the performance boost to a jumpseater or somesuch and blasted off. They got a huge boost and unbelievable performance. Through a couple hundred feet altitude both engines flamed out and they managed to safely land on the (fortunately) frozen river. It later turned out that an old water/meth drum had been filled with a witch's brew of waste oil/thinners/fuel, and the contents of that drum ended up in the tanks.
What a ride! They ended up towing the plane back up onto the airport on its own wheels and I believe it's still flying today.
Joined: Jul 2001
Posts: 30
Likes: 0
From: the other side of morning
Some extra info on AWI from the SA227-BC ( Metro III) AFM.
Engine: Garrett TPE331-12UA
ENGINE OPERATION WITH CONTINUOUS ALCOHOL-WATER INJECTION (CAWI)
The CAWI system may not be operated if the AWI fluid has been exposed to ambient temperatures below -24'C within the preceding one hour.
Minimum OAT for AWI operation......-6'C
Mixture Composition % of volume:
Methanol 40%, Water 60%
The approximate freezing point of the AWI fluid is -31'C (-24'F).
Engine: Garrett TPE331-12UA
ENGINE OPERATION WITH CONTINUOUS ALCOHOL-WATER INJECTION (CAWI)
The CAWI system may not be operated if the AWI fluid has been exposed to ambient temperatures below -24'C within the preceding one hour.
Minimum OAT for AWI operation......-6'C
Mixture Composition % of volume:
Methanol 40%, Water 60%
The approximate freezing point of the AWI fluid is -31'C (-24'F).
Joined: Feb 2000
Posts: 1,256
Likes: 1
From: CYZV
The same thing happened to a 748 on Anticosti Island, on a dirt strip at a hunting camp. Loaded both W/M tanks with JP4. They never even got airborne before the right engine cooked. Everybody got out ok, but the whisperliner was a writeoff.
The US military, the Navy I think, used to operate the G1. One aircraft had been operating wet most every takeoff all summer long. Their procedure was to call for the water off right after the gear came up. On one dry takeoff that autumn, the F/O selected gear up and hit the W/M at 15,000 RPM. They got the aircraft around and back on the ground, but they had to change everything from the firewalls forward.
Something similar happened to a Martin 404 in GSO. A famous singer bought one offa Southern Airways, and he had his own pilots on it. They were getting about 20 hours on their engines and maintenance couldn't figure out why. One day they were in GSO on a layover and a Piedmont flight was there, so they asked the Captain to give them some airwork. They were motoring down the runway with the power set, when the Captain looked over at the F/O and told him to "double clutch that mother******." The F/O reached up and hit the ADI switches. Solved the premature removal problem right there.
[ 13 November 2001: Message edited by: pigboat ]
The US military, the Navy I think, used to operate the G1. One aircraft had been operating wet most every takeoff all summer long. Their procedure was to call for the water off right after the gear came up. On one dry takeoff that autumn, the F/O selected gear up and hit the W/M at 15,000 RPM. They got the aircraft around and back on the ground, but they had to change everything from the firewalls forward.
Something similar happened to a Martin 404 in GSO. A famous singer bought one offa Southern Airways, and he had his own pilots on it. They were getting about 20 hours on their engines and maintenance couldn't figure out why. One day they were in GSO on a layover and a Piedmont flight was there, so they asked the Captain to give them some airwork. They were motoring down the runway with the power set, when the Captain looked over at the F/O and told him to "double clutch that mother******." The F/O reached up and hit the ADI switches. Solved the premature removal problem right there.
[ 13 November 2001: Message edited by: pigboat ]
Paxing All Over The World
Joined: May 2001
Posts: 10,841
Likes: 328
From: Hertfordshire, UK.
I understand that the BAe Jetsream 41 has a water/meth facility. If memory serves, they use the Garrett.
The pilot who explained about this process said that the bean counters don't like them to use it unless they REALLY have to. But then, the same bean counters also asked f/c to try and turn off the wing tip 'conspics' lights as soon as poosible after departure ... as the bulbs are expensive!! Not sure how many of these bulbs you have to save before you equal the cost of a J41 involved in a mid-air because it wasn't visible?
[ 13 November 2001: Message edited by: PAXboy ]
The pilot who explained about this process said that the bean counters don't like them to use it unless they REALLY have to. But then, the same bean counters also asked f/c to try and turn off the wing tip 'conspics' lights as soon as poosible after departure ... as the bulbs are expensive!! Not sure how many of these bulbs you have to save before you equal the cost of a J41 involved in a mid-air because it wasn't visible?
[ 13 November 2001: Message edited by: PAXboy ]
Thread Starter
Joined: May 2001
Posts: 143
Likes: 0
From: Frankfurt, Germany
Elliot Moose
The HS-748 was a great aircraft. I remember flying into and out of Bern-Belp, Switzerland on a Dan-Air 748.
I am not sure if Water Injection on the take-offs, but in those days the runway was comparitively short and compared to other airports it seemed to be real seat-of-the-pants stuff.
I have not been back for years so I expect it has changed a great deal since then. Maybe even the "terminal" shed has gone!
The HS-748 was a great aircraft. I remember flying into and out of Bern-Belp, Switzerland on a Dan-Air 748.
I am not sure if Water Injection on the take-offs, but in those days the runway was comparitively short and compared to other airports it seemed to be real seat-of-the-pants stuff.
I have not been back for years so I expect it has changed a great deal since then. Maybe even the "terminal" shed has gone!
Joined: Feb 2000
Posts: 116
Likes: 0
From: Montreal
ramsrc
Whaddaya mean WAS!? There's still a whole pile of them flying here in the great white north. Most have been well modified. Almost all have some form of supplemental heat (designed for Britain where it's not too hot and not too cold--we get both extremes), but some have a lot more. Many are carrying freight, and as such have a lot of the familiar furnishings removed--including pressurization (those superchargers are heavy) windows, baggage doors, and in a few cases a 9ft hole has been cut in the side of an unpressurized beast and a roller floor installed to accomodate pallets and large reight. The most modded one I flew was a fuel tanker conversion. It had been depressurized, had all but the forward freight door removed, windows sheeted over and all but the centre floorboards removed. The cockpit was sealed up pretty well and double insulated. 200V AC heat was installed as well as a bleed air heat system. A King silver crown stack (much like a Cessna caravan or King Air) was installed in the main panel and all the engine instruments squished over to accomodate it. They also installed a 10h.p. honda engine as an APU which had a hydraulic pump and generator installed as accessories. The hydraulics were used to operate fuel pumps down in the belly. Ten 250gal tanks (US army surplus from a C5 Galaxy installation)are installed in the main fuselage and the outboard 15ft or so of wing tank is partitioned off and plumbed into the payload system. This allowed the aircraft to be landing weight limited instead of ZFW on short hauls. Loading and unloading was done by means of single point refuelling points located on the left lower fuselage forward and aft of the wing.
We were able to take a total load of 9250L of unleaded fuel on a short leg VFR(less red diesel or Jet B since they weigh more), which meant it was just a big flying fuel-air bomb.
Standard SAR procedure would be to find the biggest forest fire and work upwind until you find the crater. It was hard dirty work, but the pay was great! 
Here's an actual picture of the beast taking off with a load on about 4yrs ago in northern Ontario.
[ 14 November 2001: Message edited by: Elliot Moose ]
Whaddaya mean WAS!? There's still a whole pile of them flying here in the great white north. Most have been well modified. Almost all have some form of supplemental heat (designed for Britain where it's not too hot and not too cold--we get both extremes), but some have a lot more. Many are carrying freight, and as such have a lot of the familiar furnishings removed--including pressurization (those superchargers are heavy) windows, baggage doors, and in a few cases a 9ft hole has been cut in the side of an unpressurized beast and a roller floor installed to accomodate pallets and large reight. The most modded one I flew was a fuel tanker conversion. It had been depressurized, had all but the forward freight door removed, windows sheeted over and all but the centre floorboards removed. The cockpit was sealed up pretty well and double insulated. 200V AC heat was installed as well as a bleed air heat system. A King silver crown stack (much like a Cessna caravan or King Air) was installed in the main panel and all the engine instruments squished over to accomodate it. They also installed a 10h.p. honda engine as an APU which had a hydraulic pump and generator installed as accessories. The hydraulics were used to operate fuel pumps down in the belly. Ten 250gal tanks (US army surplus from a C5 Galaxy installation)are installed in the main fuselage and the outboard 15ft or so of wing tank is partitioned off and plumbed into the payload system. This allowed the aircraft to be landing weight limited instead of ZFW on short hauls. Loading and unloading was done by means of single point refuelling points located on the left lower fuselage forward and aft of the wing.
We were able to take a total load of 9250L of unleaded fuel on a short leg VFR(less red diesel or Jet B since they weigh more), which meant it was just a big flying fuel-air bomb.
Standard SAR procedure would be to find the biggest forest fire and work upwind until you find the crater.
It was hard dirty work, but the pay was great! Here's an actual picture of the beast taking off with a load on about 4yrs ago in northern Ontario.
[ 14 November 2001: Message edited by: Elliot Moose ]
Joined: Oct 1998
Posts: 468
Likes: 0
From: UK
And there was this German BAC 1-11 with Jet Fuel in the tanks...it took off and the crew managed an emergency landing on a mototway near Hamburg....the female copilot of this flight died later unfortunately on a crash in bad weather hitting an antenna mast on short final operating a Citation.
