Harrier water injection
Water Injection?
It reminds me of a conversation once upon a time that went a bit like this when I was Duty Auth and in swaggered a visiting JJF&HHST* mate asking "Have you any de-ionised water?"
Quick as a flash the Rects Chief said with a smirk "Did you bring your travel iron with you, Sir? I can ask the Mess if they can help?" To which I added "He'll need more than a small iron to bring the creases out of those ridiculous flaps on his boots, Chief!"
The Harrier jock looked most unamused and said "No it's for my engine!". Then the JEngO chipped in hardly looking up "We normally put AVTUR in engines mate".
Off he toddled shaking his head "I'll take that as a No then..!"
*Jump Jet Fanny & Her Hawker Siddley Tw@t
It reminds me of a conversation once upon a time that went a bit like this when I was Duty Auth and in swaggered a visiting JJF&HHST* mate asking "Have you any de-ionised water?"
Quick as a flash the Rects Chief said with a smirk "Did you bring your travel iron with you, Sir? I can ask the Mess if they can help?" To which I added "He'll need more than a small iron to bring the creases out of those ridiculous flaps on his boots, Chief!"
The Harrier jock looked most unamused and said "No it's for my engine!". Then the JEngO chipped in hardly looking up "We normally put AVTUR in engines mate".
Off he toddled shaking his head "I'll take that as a No then..!"
*Jump Jet Fanny & Her Hawker Siddley Tw@t
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Ah, those halcyon old days Leon. The fighter pilots of today don't quip as much though...probably because they actually go on operations these days, and stay on them.
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Yaw had to be carefully controlled during the decel to the hover as getting out of balance, and inducing large side slips by decel'ing out of wind for example, could result in Intake Momentum Drag (IMD) which would induce a extreme, and normally uncontrollable, yaw and roll which was nearly always unrecoverable unless caught very early on. We had what was basically a small weather vain on the nose of the aircraft and so long as you kept the vain straight i.e into the relative wind you were fine.
Once in the hover later generations of Harrier, with SAAHRS (akin to helicopter stabs although I've probably got the abbreviation wrong, it's been a while) where fairly comfortable to fly, but I would say it was never easy and required you to always be on your game. As you correctly observe the Harrier could bite, and bite fast and could very quickly go from all fine to 'Oh S&@t!!' especially for junior guys new to the jet.
As for did the best pilots go the Harrier.......absolutely!
Once in the hover later generations of Harrier, with SAAHRS (akin to helicopter stabs although I've probably got the abbreviation wrong, it's been a while) where fairly comfortable to fly, but I would say it was never easy and required you to always be on your game. As you correctly observe the Harrier could bite, and bite fast and could very quickly go from all fine to 'Oh S&@t!!' especially for junior guys new to the jet.
As for did the best pilots go the Harrier.......absolutely!
Last edited by AutoBit; 2nd Dec 2016 at 22:04.
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The R-R Pegasus used distilled water injection at the combustor to keep turbine inlet temps within acceptable limits during hover. The injected water reduces gas temps thru latent heat of evaporation. Since the injected water is inert, it does not contribute to the combustion process, but it does absorb heat which reduces the gas temp at the start of combustion, and thus allows a greater mass of fuel to be added to the existing airflow without exceeding turbine inlet temp limits.
Technically, the water injection does not "cool the engine". It simply lowers the temperature of the compressed air flow at the start of combustion. Gas turbine engines are typically limited by turbine inlet temps, or basically peak combustion cycle temps. So reducing gas temp at the start of combustion allows for a larger temperature rise during combustion. This means more fuel can be burned, and more heat energy added to the exhaust gas.
Technically, the water injection does not "cool the engine". It simply lowers the temperature of the compressed air flow at the start of combustion. Gas turbine engines are typically limited by turbine inlet temps, or basically peak combustion cycle temps. So reducing gas temp at the start of combustion allows for a larger temperature rise during combustion. This means more fuel can be burned, and more heat energy added to the exhaust gas.
I've known a great many Harrier drivers over the years. Most of them were good, but I'm sure most of them would reluctantly admit they did take themselves/life much too seriously. The banter at Gutersloh between the guys on 230 Sqn and Harrier mates was simply fantastic to observe! The youngsters didn't stand a chance against Messrs Carpenter & Blackie!
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Good to see this thread has degenerated into the usual Harrier pilot slagging off match.
By the way Leon J, if I was the Duty Auth on a sqn that treated visiting aircrew in the rude, discourteous and unprofessional manner that you boast about I would have been embarrassed.....not bragging about it.
By the way Leon J, if I was the Duty Auth on a sqn that treated visiting aircrew in the rude, discourteous and unprofessional manner that you boast about I would have been embarrassed.....not bragging about it.
Tartare
Actually not very difficult to fly - with the nozzles aft it was a big Hawk, in the VSTOL regime handling was slightly more challenging but no black art.
The problem was how close to the edge you were in the VSTOL regime - very black and white between all going fine and nope I've crashed. Mostly down to the balance of fuel water and performance and a few minutes/seconds of criticality to work to - particularly from the deck with few outs. In most other jets there is a bit more grey - if I've screwed it up a bit I'll still get it back under control minus a few heartbeats.
Autobit
Indeed, but then you weren't aggressively low average....😉
Actually not very difficult to fly - with the nozzles aft it was a big Hawk, in the VSTOL regime handling was slightly more challenging but no black art.
The problem was how close to the edge you were in the VSTOL regime - very black and white between all going fine and nope I've crashed. Mostly down to the balance of fuel water and performance and a few minutes/seconds of criticality to work to - particularly from the deck with few outs. In most other jets there is a bit more grey - if I've screwed it up a bit I'll still get it back under control minus a few heartbeats.
Autobit
Indeed, but then you weren't aggressively low average....😉
Oh dear, I must write more clearly, with exactitude and precision.
The B-team refers to those not blessed with the title of Bona-mate. - a pathway to camping in swamps, crapping in Field toilets and digging jets out of
bogs when they slip off the tin. Jealousy is a dreadful thing.
The B-team refers to those not blessed with the title of Bona-mate. - a pathway to camping in swamps, crapping in Field toilets and digging jets out of
bogs when they slip off the tin. Jealousy is a dreadful thing.
Harrier pilots had to get helicopter pilots to teach them how to hover. IIRC, they were given 5 hours at Shawbury, during my QHI'ing time there.
Most were probably unaware that teaching them to hover a Gazelle at Harrier hover heights (in the avoid curve) wasn't a particularly happy time for their QHIs. Obviously, "Bang seat let down" in the event of an engine failure wasn't an option.
Having been given the opportunity to fly the T4 from Gutersloh, I can say that it was quite stable in the hover compared to most helicopters. The approach on the braking stop was a bit weird, I have to admit, being very used to nose up to decel a helicopter.
Most were probably unaware that teaching them to hover a Gazelle at Harrier hover heights (in the avoid curve) wasn't a particularly happy time for their QHIs. Obviously, "Bang seat let down" in the event of an engine failure wasn't an option.
Having been given the opportunity to fly the T4 from Gutersloh, I can say that it was quite stable in the hover compared to most helicopters. The approach on the braking stop was a bit weird, I have to admit, being very used to nose up to decel a helicopter.
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I seem to recall flying the helicopter during the Shawbs Harrier course as:
a. Great fun
b. Of no practical or relevant use to prepare for Harrier STOVL
c. Quite easy to get to grips with
Like most things, the devil is in the detail and I wouldn't presume to apply the ease of hovering in a field near Ternhill to landing a Lynx on a bucking Frigate deck, or infil-ing an SF team into a compound at night, lights out on NVG, with little power margin. Similarly, one shouldn't discount that STOVL was a means to an end and, though it was unquestionably challenging at times, there was often a mission between take off and landing events.
The key delineator in ability was the prospective Harrier pilot's skill to consistently produce a safe, textbook VL or Slow Landing at the end of a very busy sortie. Those that couldn't, didn't last. Those that could, earned their place.
a. Great fun
b. Of no practical or relevant use to prepare for Harrier STOVL
c. Quite easy to get to grips with
Like most things, the devil is in the detail and I wouldn't presume to apply the ease of hovering in a field near Ternhill to landing a Lynx on a bucking Frigate deck, or infil-ing an SF team into a compound at night, lights out on NVG, with little power margin. Similarly, one shouldn't discount that STOVL was a means to an end and, though it was unquestionably challenging at times, there was often a mission between take off and landing events.
The key delineator in ability was the prospective Harrier pilot's skill to consistently produce a safe, textbook VL or Slow Landing at the end of a very busy sortie. Those that couldn't, didn't last. Those that could, earned their place.
The Shawbury helo course was known as the 'walkabout course' because it involved wandering about until a chap said get in this helicopter and do it. ... and they certainly said it was an unhappy envelope corner, but they could have been sergeant pilots.
No checks, no navigation, no airmanship at all, just watching a speedo drop to nothing and then persuading a clattering heap of aluminium on to the ground.
I was told that the ab initio Bona-mates ablity to pick up helicopter skill quickly in this unloaded environment led to the helo course being changed to reflect this style of syllabus.
Helos are pleasingly responsive in the hover, harriers have a sluggish inertia, T4 harriers are sluggisher, heavier and usually with about 2 minutes of fuel to practise with. ..and a QFI in the back to complain.
No checks, no navigation, no airmanship at all, just watching a speedo drop to nothing and then persuading a clattering heap of aluminium on to the ground.
I was told that the ab initio Bona-mates ablity to pick up helicopter skill quickly in this unloaded environment led to the helo course being changed to reflect this style of syllabus.
Helos are pleasingly responsive in the hover, harriers have a sluggish inertia, T4 harriers are sluggisher, heavier and usually with about 2 minutes of fuel to practise with. ..and a QFI in the back to complain.
