MiG-21 used plain water for AB?!!

[Vekkinho]

I just witnessed CroAF MiG-21bis overhaul in ZTZ-Zagreb (maintenace facility) and mechanics tested it's r-25-300 engine.

 

I spoke to one of the mechanics I met there on fuel consumption during AB use and he told me something I can really believe!

 

He said that there's no additional fuel needed for AB to kick in and fuel consumption remains the same as with Full Military throttle.

 

He also mentioned and showed me something that can be best described as a shower handle that injects plain water into exhaust. It's a simple pipe with lots of small holes so when the water hits hot nozzle it desintegrates into 2 X Hydrogen and Oxygen and burning Hydrogen creates additional power.

 

I find it hard to believe or I might have understood it wrong!

 

What do you guys think?!

[golfsierra2]

He also mentioned and showed me something that can be best described as a shower handle that injects plain water into exhaust. It's a simple pipe with lots of small holes so when the water hits hot nozzle it desintegrates into 2 X Hydrogen and Oxygen and burning Hydrogen creates additional power.

 

 

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Best that it would do is create some steam, but that would not cause extra thrust, it only cools down the exhaust gases. The amount of energy still comes 100% from the fuel, and by water no extra energy is added ...

[Pilotasso]

Watter is commonly used to aid in air compression.

It evaporates very rapidely as air heats up into the compressors stages and promotes higher compression rates. It also results into more gas flow being fed to the combustion chamber and higher expansion down to the nozzle providing extra thrust. But this method has being phased out for years as better alloys allow higher operating temperatures to provide the same compression rates.

 

Never heard about using it as fuel because in order to decompose it, it will have to decrease the exaust gases in the first place.

[nscode]

I did hear of fireman going "omg, why isn't this water putting out this chemical fire", and it was because of precisely that, it decomposing... but that was at 6000 K. The exhaust temp far less.

[Kula66]

I think (but could be totally wrong) that Sea Harriers used it while hovering ... hence they were limited to how long they could hover by the amount of water they carried.

[Fjordmonkey]

I think (but could be totally wrong) that Sea Harriers used it while hovering ... hence they were limited to how long they could hover by the amount of water they carried.

 

The Harriers use water for cooling, as far as I know. Without it, the Pegasus-engine would say byebye pretty fast in a hover =)

[mcnab]

I just witnessed CroAF MiG-21bis overhaul in ZTZ-Zagreb (maintenace facility) and mechanics tested it's r-25-300 engine.

 

I spoke to one of the mechanics I met there on fuel consumption during AB use and he told me something I can really believe!

 

He said that there's no additional fuel needed for AB to kick in and fuel consumption remains the same as with Full Military throttle.

 

He also mentioned and showed me something that can be best described as a shower handle that injects plain water into exhaust. It's a simple pipe with lots of small holes so when the water hits hot nozzle it desintegrates into 2 X Hydrogen and Oxygen and burning Hydrogen creates additional power.

 

I find it hard to believe or I might have understood it wrong!

 

What do you guys think?!

 

Well, the mechanic was either talking rubbish (unlikely) or there was a little communication problem there between you two (likely).

[Fjordmonkey]

Also know that the B52 use a water-injection-system. No idea why, though.

[Pilotasso]

The watter injection engines use today is merely for washing the engine on the ground, nothing more.

[Kula66]

Cheers IK ... Interesting.

[rogue_blade]

i race my street car with my water injected turbo :P

[kyborgs]

Time ago, i saw video on youtube, also about this water injection;

 

[Vekkinho]

What's that?!

 

A jet bike?!!

[nscode]

MiG-21 designers must have seen it on YT too :D

[thesystem]

Maby not water but hydrogen?

[Fjordmonkey]

Maby not water but hydrogen?

 

Too volatile since it'll go boom when it comes into contact with oxygene.

[Vekkinho]

Maby not water but hydrogen?

There's 2 atoms of hydrogen and 1 of oxygen in H2O molecule (water)...

[SwingKid]

Wow, I didn't even open this topic until now because I thought it was widely known.

 

Yes, the right amount of water squirted into the engine can produce a large increase in thrust, as long as it fully and instantly evaporates from a compact liquid into a high-pressure vapor. The Soviets definitely fielded this on some early MiG, although I can't remember now if it was the MiG-21 or already on the first MiG-17F.

 

That's the first time I heard of an afterburner that doesn't dramatically increase fuel consumption, however. I think there was a misunderstanding on that part.

 

-SK

[VMFA117_Poko]

The Soviets definitely fielded this on some early MiG, although I can't remember now if it was the MiG-21 or already on the first MiG-17F.

So GS ;) Nobody needs go back to school. Vekkinho didn't totally misunderstood the technician either. Can someone confirm this. Alfa mayby? I can't find any info about this...

[thesystem]

Don't know if i have to believe this site but it also speaks of wate rinjection to increase the thrust

http://www.factmonster.com/ce6/sci/A0859034.html

[Rolim]

From the site indicated:

 

"Injection of water into the air-compressor inlet also increases the thrust, but can be used only at take-off because of the high water consumption."

 

In fact it was used not only in fighters, but in civilian passenger planes also, like the Fokker F-27/FAirchild-Hiller FH-227 (and every plane equipped with Rolls-Royce Dart engines). In this case, not only water, but a mix of water+methanol.

 

I know this because I worked with that planes before.

 

But in Brazil we don't have them anymore.

[WhiskeyRomeo]

He said that there's no additional fuel needed for AB to kick in and fuel consumption remains the same as with Full Military throttle.

 

He also mentioned and showed me something that can be best described as a shower handle that injects plain water into exhaust. It's a simple pipe with lots of small holes so when the water hits hot nozzle it desintegrates into 2 X Hydrogen and Oxygen and burning Hydrogen creates additional power.

After burning is dumping raw fuel into the combustion chamber. I don't see how that wouldn't do anything but increase the fuel flow rate.

 

Water injection is a well known way to increase engine thrust. It's not because of the water's hydrogen burning. It's the "weight" of the extra thrust the engine can generate with cooling.

"The maximum power a turbine engine can output depends largely upon the density or weight of the flow of the gases through the engine. Therefore, when the atmospheric pressure decreases or ambient air temperature increases, there is a loss in thrust. The power output can be boosted or restored by cooling the airflow with water or coolant."

http://cobweb.ecn.purdue.edu/~propulsi/propulsion/jets/basics/water.html

[Force_Feedback]

But isn't it better just to have more fuel instead? Jet fuel is like 0.8 the weight of water, so you can have 20% more fuel, weight wise. Then you need seperate water tanks, plumbing, a water NOW! T-bar in the cockpit, not to mention a 'fuel' truck that has a water connector. Seems to me it is better to have more fuel than water, even complexity wise.

[SwingKid]

But isn't it better just to have more fuel instead? Jet fuel is like 0.8 the weight of water, so you can have 20% more fuel, weight wise. Then you need seperate water tanks, plumbing, a water NOW! T-bar in the cockpit, not to mention a 'fuel' truck that has a water connector. Seems to me it is better to have more fuel than water, even complexity wise.

 

Yeah, but then you need to make the engine heavier in order to distribute the excess heat. Water would give you extra thrust without increasing the temperature of the engine.

 

I think..

 

-SK

[Mugatu]

The harrier did and still does use water injection for hovering when required:

 

Power plant: 1x Rolls-Royce F402-RR-408, 22,200/23,400 lbf thrust (without/with water injection)

 

F=MA

 

http://www.freepatentsonline.com/4395874.html