Simviation Forums

Posted: **Wed Apr 21, 2010 12:26 pm**

With all the news coverage about the Iceland volcano, and how the ash could "gum up" a jet engine, I was wondering what effect it might have on a piston engined aircraft or turboprop? Last night BBC AMERICA had a reporter up in a chopper checking out the latest eruption and ash plume and there was actually lightning dancing around the cloud. COOL!

Now if only they could have something like that in flightsim for you to go check out!

Posted: **Wed Apr 21, 2010 1:54 pm**

Volcanic Ash can abrade and damage the fragile blades on a Turbine Engine whilst passing through the complete engine from front to back.

I think that the worst that can happen on a Piston Engine powered Aeroplane would be to clog up the air filter(s) to the Carburettor(s), and reduce the air supply to the cylinders. A regular Air Filter check/change would be necessary.

I'm not sure if the abrasive ash would adversely affect the surface of the rapidly rotating propellers?

Paul...Piston Props are the way to go?....

...

...!

Posted: **Wed Apr 21, 2010 7:48 pm**

From my understanding, the ash will affect any type of aircraft engine. It's as if you were rubbing every element of your engine (and propellers!) with sandpaper. It can really mess things up!

Posted: **Wed Apr 21, 2010 8:51 pm**

The biggest problem turbine engines encounter isn't just the abrasive action, but the fact that the internals are hot enough to melt the silica in the ash into glass, which bonds to the blades and can cause big problems.

Posted: **Wed Apr 21, 2010 9:57 pm**

Foz is mostly right, it would all be caught in the air filter. That is assuming that the pilot is using his air filter at the time. If for some reason carburetor heat is being used, then the air coming in is unfiltered and the abrasive ash would be drawn into the cylinders with the air. I suspect that this would destroy an engine. It would grind off the chrome plating or case hardened layer inside the cylinders. It would probably do some serious damage to the valves too, but if you need all new cylinders, what's a few valves?

I could see it damaging props like others have mentioned, but think about the wind shields. Plexiglass is so sensitive that you can't use paper towels on it.

Posted: **Wed Apr 21, 2010 11:38 pm**

The biggest problem turbine engines encounter isn't just the abrasive action, but the fact that the internals are hot enough to melt the silica in the ash into glass, which bonds to the blades and can cause big problems.

True, but a bigger problem is that the melted ash blocks the tiny cooing hole in the nozzle guide vanes that are at the exit of the combustion chamber and in front of the HP turbine. If these holes are blocked then the temperature of the air leaving the combustion chamber will burn away the NGV's and then start on the turbine. It also gets into the lubrication system stopping cooling and sealing air entering the labyrinth seals of the oil sumps causing the oil to turn into something like treacle and causes overheating of the oil system. Both of these are the extreme, but it does not take much to get to this stage.

Matt

Posted: **Thu Apr 22, 2010 10:33 am**

Apparently parts of the high pressure turbine operate in exhaust gas that is a few hundred degrees hotter than the turbines melting point. They rely on cooling to prevent them from melting. Apparently molten glass can block off cooling and cause significant damage.

Posted: **Thu Apr 22, 2010 10:51 am**

Similar to Volcanic Ash...

I wonder if Aircraft, (Turbine and Piston props), are grounded during local sand storms?
Every now and again, Sydney, Australia, suffers from Sand/Dust storms blown in from the desert, and I wonder if the local Aircraft allowed to pass through it?

Cairo Airport looks rather sandy, as well...

...!

http://en.wikipedia.org/wiki/File:Cairo ... -_NASA.JPG

Paul...beachcomber... 8-)...!

Posted: **Thu Apr 22, 2010 1:47 pm**

I have to smile at the news and even some things written here. People are obsessed with engines. I suppose it is the only thing that people really understand. I was reading "just for fun" the maintenance procedure for ash checks on 737NG today. The systems that have to be checked, well it would be easier to tell you what is not checked! Cabin lights and that is about it. Every other system has to be checked and in the vast majority of cases removed to be checked. Right down to the flush valve in the toilet. All the news "experts" and blog comments about the airlines and money and playing with pax safety, people have no idea what so ever what it would involve if an aircraft flew in ash, not to mention the image damage if something went wrong (has killed of some big names after crashes). Then comes the stupid remarks about them flying aircraft anyway. Not this inspector. I am not putting my life, lively hood and freedom on the line (how many here could go to prison if they phuq up at work) just because my company tells me I have to release an aircraft. They would be in more poop that me if they did. It just aint gona happen. Sorry if this is a bit rambling, but I have just done a 14 hour shift........not ash related, just run of the mill AOG.

But at the end of the day, you can always tell and armchair expert................But you can't tell him much!

Matt

Posted: **Thu Apr 22, 2010 6:22 pm**

I have to smile at the news and even some things written here. People are obsessed with engines. I suppose it is the only thing that people really understand. I was reading "just for fun" the maintenance procedure for ash checks on 737NG today. The systems that have to be checked, well it would be easier to tell you what is not checked! Cabin lights and that is about it. Every other system has to be checked and in the vast majority of cases removed to be checked. Right down to the flush valve in the toilet. All the news "experts" and blog comments about the airlines and money and playing with pax safety, people have no idea what so ever what it would involve if an aircraft flew in ash, not to mention the image damage if something went wrong (has killed of some big names after crashes). Then comes the stupid remarks about them flying aircraft anyway. Not this inspector. I am not putting my life, lively hood and freedom on the line (how many here could go to prison if they phuq up at work) just because my company tells me I have to release an aircraft. They would be in more poop that me if they did. It just aint gona happen. Sorry if this is a bit rambling, but I have just done a 14 hour shift........not ash related, just run of the mill AOG.

But at the end of the day, you can always tell and armchair expert................But you can't tell him much!

Matt

[color=#000000]Well said, especially the last sentence.

Posted: **Fri Apr 23, 2010 6:38 am**

Interesting discussion here guys

At least I know now not to go flying my sim when any volcanic ash is around!

Posted: **Mon May 17, 2010 6:20 pm**

Looks like it erupted again, leaving more volcanic ash...

http://news.yahoo.com/nphotos/Iceland-v ... 36721fcebe

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