As a former Harrier engineer, specifically on the Pegasus, I'll just mention that the water isn't for 'cooling the engine', it's for 'fooling the engine'. I've copied this technical jargon from PPrune, as it's very well explained. 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...
Yeah, the explanation of the water is pretty rough. Basically, the tl:dr is that your engine uses the temperature of the air to determine how much thrust it can provide. The water fools the engine into thinking the outside air is cooler and so it will work harder. When the water runs out, the engine reads the correct temperature and reverts back to correct thrust. It's not a self preservation mode and it won't explode. At worst, in certain cases (not all), if your water depletes in the hover, your thrust will reduce and you'll lose lift. Your engine is never at risk over-revving or overheating. Thanks for the video, it was very helpful!
Fooling is the wrong word i think? Because to fool the engine you could just change the readout of the temp sensor. No, the water made the air cooler and denser which gives you more power. So there is a real change to the conditions the engine gets. On todays airliners this is not used anymore because they just us a larger engine. In the very confined space in a harrier on the other hand they try to get the most out of the small engine they have to work with.
@@thomasochsner5002 You’re fooling the engine into believing the conditions are general, not localised and created by you for the purpose of producing more power. Trust me, I worked on them for a living.
@@Quantiad i dont want to question your integrity. I myself did work only on engines without water injection. Do you know where the Pegasus did the injection? On which stage(s)?
@@thomasochsner5002 It’s just semantics anyway, ‘fooling’ the engine etc. The water is injected into the combustion chamber, lowering the temperature readout in the turbine.
Thank you. Very nice. Before afterburners most jets were water injected to increase thrust. And in ww2 some piston airplanes. So since no after burner would be practical in this aircraft, Went back to water injection. Also this simulator makes hovering look easy. It is actually like balancing on a beach ball. Thanks again, cheers
RCS valves in the wingtips for roll, nose and tail for pitch, tail for yaw. If you run out of water, the engine controller will adjust the JPT limit so you shouldn't cook the engine, you might crash though! Engine is JPT limited, water should come on at about 90% throttle position.
I've been flying the Harrier for a few months now. When I get slow on landing, I get a rocking/wobbling motion. I haven't sorted that out. I also notice the Harrier mirrors do not work (mine have an image frozen on them and that's it). I was also observed on the landing the water count doesn't seem to move (fine by me!).but wasn't sure if that was accurate or not. I don't recall the channel I was watching recently but a real Harrier pilot was trying the DCS Harrier for the first time. A very fun and informative video if you come across it!
The rocking/wobbling is probably either pilot induced oscillation or (PIO) which is caused by basically over correcting to balance the aircraft as unlike helis you are standing on thrust and not siting under it so it can be quite a bit harder. It could also be slight variations in thrust due to turbulence and the like from the engine. I'm not sure how much that affects the aircraft though so the PIO is probably more likely. It can also be caused by wind gusts but since this is DCS the wind isn't that strong if on at all most of the time. I'd love to hear from anyone who worked on or with them though if i made any mistakes.
has the flight model been drastically changed in 3 years? on the 'above 100% power time' is that just for take off and landing or all flight? surely full power is available at higher altitudes for longer due to lower air temps? im trying to get a handle on how it all works...... im an AV-8B noob hahaahaaa
Lol. This is harder than it looks! I can get within 50 metres of the ground and then the nose pitches violently upwards and then I go backwards and downwards at a terminal rate! Up until that point, my approach seems to be OK. I notice that you are trimming all the way down just about, but I wonder if I have applied too much as I am trying to do the same. I’ll just keep practicing I guess...
The nose is probably pitching due to the thrust reflecting off the ground and pushing you, I think this is part of the reason you are supposed to keep the witch's hat just above 5 degrees but I'm not entirely sure.
robert schollmeyer - it seems that practice is the key. Since I wrote this comment I have practiced a lot and it seems that fine throttle control and constant re-trimming of the angle of attack is the key. I am by no means smooth, but I can at least land it in a hover most of the time now! Side to side Pilot Induced Oscillation is mostly what gets me now, but again, that’s just practice and stopping myself from over-correcting! The Harrier is my favourite plane in DCS!
Man don't I love how these comments on half these types of videos are like the hoggit SR I think he's just trying to teach people how to just do it yk the basics
tfw you had no clue the engine could go above 100% and have powerwalled the throttle even for just regular cruising. that explains all the hexagon nonsense.
Its 83º not 85º. Also, you dont nose up until you're actually generating aerodynamic lift, all you're doing is reducing thrust through cosine losses. You dont have to raise your nose so far up to slow down during landing either, the nozzles go past 83º for a reason. Put them to 99º and you'll slow down without needing to look like a clown. Good practise when doing VTOL is to keep the nose level and handle forward/backward velocity with just the nozzles.
As a former Harrier engineer, specifically on the Pegasus, I'll just mention that the water isn't for 'cooling the engine', it's for 'fooling the engine'. I've copied this technical jargon from PPrune, as it's very well explained.
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...
11/10 tech explanation and raconteuring. I'd like to imagine I'd be this detailed and entertaining if I were experienced with the Pegasus myself.
so a vodka induced turbine work the best? that explain the ruski jet performance then
You get the AWARD 🥇 for best RUclips comment ever
I thank you for helping bring my favorite aircraft to life
this would be really cool to read if i knew how engines worked
Yeah, the explanation of the water is pretty rough. Basically, the tl:dr is that your engine uses the temperature of the air to determine how much thrust it can provide. The water fools the engine into thinking the outside air is cooler and so it will work harder. When the water runs out, the engine reads the correct temperature and reverts back to correct thrust. It's not a self preservation mode and it won't explode. At worst, in certain cases (not all), if your water depletes in the hover, your thrust will reduce and you'll lose lift. Your engine is never at risk over-revving or overheating.
Thanks for the video, it was very helpful!
Thx Sir
Fooling is the wrong word i think? Because to fool the engine you could just change the readout of the temp sensor.
No, the water made the air cooler and denser which gives you more power. So there is a real change to the conditions the engine gets. On todays airliners this is not used anymore because they just us a larger engine. In the very confined space in a harrier on the other hand they try to get the most out of the small engine they have to work with.
@@thomasochsner5002 You’re fooling the engine into believing the conditions are general, not localised and created by you for the purpose of producing more power. Trust me, I worked on them for a living.
@@Quantiad i dont want to question your integrity. I myself did work only on engines without water injection.
Do you know where the Pegasus did the injection? On which stage(s)?
@@thomasochsner5002 It’s just semantics anyway, ‘fooling’ the engine etc. The water is injected into the combustion chamber, lowering the temperature readout in the turbine.
I only needed this to see the landing procedure for a better landing in war thunder, but now I know how to do actual vtol. I couldn't thank you enough
Get outta here you war thunder panzy
Jk war thunder is actually pretty neat (dcs is just better)
@@cayohowells2507 (agreed)
@@andriys.1860 (agreed)
You bought a premium vehicle and didn’t even know how to land huh? Seems about right.
@LeviandTominHD are we born knowing how to land? Like a damn baby bird?
Thank you. Very nice. Before afterburners most jets were water injected to increase thrust. And in ww2 some piston airplanes. So since no after burner would be practical in this aircraft, Went back to water injection. Also this simulator makes hovering look easy. It is actually like balancing on a beach ball. Thanks again, cheers
Charles Emigh Bruh I’m the Beach Ball Balancing World Champion dude smh.
RCS valves in the wingtips for roll, nose and tail for pitch, tail for yaw. If you run out of water, the engine controller will adjust the JPT limit so you shouldn't cook the engine, you might crash though! Engine is JPT limited, water should come on at about 90% throttle position.
Yes, RCS valves were called 'puffer ducts' in RAF - just used in hover.
Big thankyou Cap for all your insanely helpful tutorials. ☘️
I've been flying the Harrier for a few months now. When I get slow on landing, I get a rocking/wobbling motion. I haven't sorted that out. I also notice the Harrier mirrors do not work (mine have an image frozen on them and that's it). I was also observed on the landing the water count doesn't seem to move (fine by me!).but wasn't sure if that was accurate or not. I don't recall the channel I was watching recently but a real Harrier pilot was trying the DCS Harrier for the first time. A very fun and informative video if you come across it!
The rocking/wobbling is probably either pilot induced oscillation or (PIO) which is caused by basically over correcting to balance the aircraft as unlike helis you are standing on thrust and not siting under it so it can be quite a bit harder.
It could also be slight variations in thrust due to turbulence and the like from the engine. I'm not sure how much that affects the aircraft though so the PIO is probably more likely.
It can also be caused by wind gusts but since this is DCS the wind isn't that strong if on at all most of the time.
I'd love to hear from anyone who worked on or with them though if i made any mistakes.
Click on the mirror using your mouse to get them to work normally
When I am done being tortured trying to fly the KA-50 I might try this module. XD
Steve Barnes What is so torturing in Ka-50? Except rotor blades occasionally hitting each other when you trying to have fun.
Nice Video, love your stuff. I've always wondered how fast can you transsion from level flight to hover and than VTOL landing?
has the flight model been drastically changed in 3 years? on the 'above 100% power time' is that just for take off and landing or all flight? surely full power is available at higher altitudes for longer due to lower air temps? im trying to get a handle on how it all works...... im an AV-8B noob hahaahaaa
Completely changed yes.
Can you do a video explaining the ILS and radar system of the M-2000. I can't understand the French instructor to save my life.
Does my current mirage ILS video in the Mirage playlist explain It or need additional? Please reply in new comment thread.
Lol. This is harder than it looks! I can get within 50 metres of the ground and then the nose pitches violently upwards and then I go backwards and downwards at a terminal rate! Up until that point, my approach seems to be OK. I notice that you are trimming all the way down just about, but I wonder if I have applied too much as I am trying to do the same. I’ll just keep practicing I guess...
The nose is probably pitching due to the thrust reflecting off the ground and pushing you, I think this is part of the reason you are supposed to keep the witch's hat just above 5 degrees but I'm not entirely sure.
robert schollmeyer - it seems that practice is the key. Since I wrote this comment I have practiced a lot and it seems that fine throttle control and constant re-trimming of the angle of attack is the key. I am by no means smooth, but I can at least land it in a hover most of the time now! Side to side Pilot Induced Oscillation is mostly what gets me now, but again, that’s just practice and stopping myself from over-correcting! The Harrier is my favourite plane in DCS!
Great job 👍👍
Could you do a video about how to operate the Harrier from a FOB or a FARP? mean, that's what the Harriers were designed for.
Sure!
this is torture. if you're into stress, buy this module
God, that made me laugh! I may be mad, but I think I'll buy it as my first module. Really enjoy the trial
Man don't I love how these comments on half these types of videos are like the hoggit SR I think he's just trying to teach people how to just do it yk the basics
Cap do you and your guys use ReShade? Should we use it?
what is it? Let me know in a new comment thread pls else I don't get notification
Can you use the stick or do you have to use the trim?
I use both
I can vtol land and takeoff but as soon as theres a boat my aircraft loses full control
tfw you had no clue the engine could go above 100% and have powerwalled the throttle even for just regular cruising. that explains all the hexagon nonsense.
Bros game is darker than my basement.
So when you in flight refuel you have to have two tankers. One for jet fuel and one for water. True story
Do you use Track Ir if yes which one?
Delan Clip
How to switch angle of nosle
Hwo can you go beyond 100% power?
Weird I know. 107% I think in this plane.
@@grimreapers ohh so full throttle in this plane is 107% power?
I just saw your tutorial. it's good but you speak very fast. :)
how to get the nozzles down??
If you go to axis commands there should be a command for it he also has a video on the bare does controller you might want to use 😃
@@headears its bad that they do not tell us
@@michaelliu1518 they do tell you in the hotas set-up video in this playlist
Its 83º not 85º. Also, you dont nose up until you're actually generating aerodynamic lift, all you're doing is reducing thrust through cosine losses.
You dont have to raise your nose so far up to slow down during landing either, the nozzles go past 83º for a reason. Put them to 99º and you'll slow down without needing to look like a clown. Good practise when doing VTOL is to keep the nose level and handle forward/backward velocity with just the nozzles.
My wont take off
Make sure you are under 23k lbs total weight and disable your parking brake before advancing throttles.
Downvoted for saying that Harrier uses water to cool that engine... Dude, thats like Harrier 101
Dude, this isn't reddit