Running Ram Air through the clouds

[crxcte]

I don't make this a habit for the obvious reason but have forgot to close the ram door before flying through clouds.   

[GeorgePerry]

this is a big no-no.  Unlike air, water is not compressible.  If there turns out to be medium to heavy precipriation in a cloud and you injest water into a cyclinder, the compression stroke will be the engine's last.

I say medium to heavy precip since moisture from the cloud will likely atomize before getting all the way into the combustion chamber.  However is liquid water gets there, it's game over.

All of that aside, I've never heard of an IO-360 destroying itself by sucking water through the ram air inlet...but I wouldn't want to be the first.

[Immelman]

I tend to close it out of habit, sort of like having the pitot heat on (ahead of time) before penetrating a cloud, but I was primarily thinking about induction ice, rather than water volume.

[crxcte]

The operation book says close in case of icing, not much on just water itself.  Seems the air filter being just foam would be subject to water as well.  Never heard of anyone having a water problem.  I also close before penetrating clouds.  

[Tom]

George, I don't know what you're talking about but IC aircraft engines just aren't prone to hydrostatic lock. 

In discussing wives tales, there is more to be said about losing RPM from trying to suck air through a water-saturated air filter than anything else.

 

[GeorgePerry]

I understand that aircraft engines are not "prone" to it, but I've seen plenty of high end auto's that have been driven through water too fast, sucked in some, and the bottom end came out in a violent fashion.  The chances of an aircraft engine doing this is slim but it only takes a couple of ounces of water in a combustion chamber to ruin an engine.

All I'm saying it that I wouldn't chance it.  Bottom Line, visible moisture = closed ram air door

[Piloto]

Quote: GeorgePerry

this is a big no-no.  Unlike air, water is not compressible.  If there turns out to be medium to heavy precipriation in a cloud and you injest water into a cyclinder, the compression stroke will be the engine's last.

I say medium to heavy precip since moisture from the cloud will likely atomize before getting all the way into the combustion chamber.  However is liquid water gets there, it's game over.

All of that aside, I've never heard of an IO-360 destroying itself by sucking water through the ram air inlet...but I wouldn't want to be the first.

[FoxMike]

Chris,

Many years ago I was climbing through a cloud deck and the engine quit.  Fortunately, I was able to reach warmer air before I hit the ground.  I thought the ram air door was closed but it turned out that a mechanic had not properly rigged the control cable during the annual inspection.  Air pressure against the door pushed it open a little and the impact tubes on the fuel servo got frozen over. When the impact tubes freeze the fuel stops flowing.  Alternate Air does not help, you need warmer air. I would certainly recommend that you keep the ram air door closed when temperatures are near freezing.  

Walt

[Mcstealth]

Quote: FoxMike

Chris,

Many years ago I was climbing through a cloud deck and the engine quit.  Fortunately, I was able to reach warmer air before I hit the ground.  I thought the ram air door was closed but it turned out that a mechanic had not properly rigged the control cable during the annual inspection.  Air pressure against the door pushed it open a little and the impact tubes on the fuel servo got frozen over. When the impact tubes freeze the fuel stops flowing.  Alternate Air does not help, you need warmer air. I would certainly recommend that you keep the ram air door closed when temperatures are near freezing.  

Walt

[tony]

got mine!!

[bjmacdonald]

This is one of the most bizzare posts ive seen in a while...It is very likely you could ice up or injest enough water flying in a monsoon to put out the fire in the cylinders, If you look at the shear size of one cylinder and figure that the water will not all go to one it is spread out you would have to fly through a water fall or skim along the ocean to ingest enough to hydrolock a cylinder on a airplane.

[GeorgePerry]

Quote: bjmacdonald

This is one of the most bizzare posts ive seen in a while...It is very likely you could ice up or injest enough water flying in a monsoon to put out the fire in the cylinders, If you look at the shear size of one cylinder and figure that the water will not all go to one it is spread out you would have to fly through a water fall or skim along the ocean to ingest enough to hydrolock a cylinder on a airplane.

[OR75]

gasoline combustion leads to water vapor and lots of it

[tony]

George, that actually did make me laugh out loud.  That’s funny.....bj, before you enter the cloud would you please make a note on your knee board? 

[bjmacdonald]

Did you guys even read my post or just make smart remarks ....I did say you probably would get ice in the induction what i was laughing about was the posibility of hydrolocking a engine its basic physics but obviously you guys are much smarter than I .

[eaglebkh]

Quote: bjmacdonald

This is one of the most bizzare posts ive seen in a while...It is very likely you could ice up or injest enough water flying in a monsoon to put out the fire in the cylinders, If you look at the shear size of one cylinder and figure that the water will not all go to one it is spread out you would have to fly through a water fall or skim along the ocean to ingest enough to hydrolock a cylinder on a airplane.

[GeorgePerry]

Quote: bjmacdonald

Did you guys even read my post or just make smart remarks ....I did say you probably would get ice in the induction what i was laughing about was the posibility of hydrolocking a engine its basic physics but obviously you guys are much smarter than I .

[Tom]

Quote: eaglebkh

A posts regarding keeping the ram air door closed because of moisture is bizarre???

[bjmacdonald]

George thanks for the appology, I think we all get the point of the subject. As for my sentence structure im not a english major and im just to lazy some times.

[231Pilot]

I usually leave the RAM air off.  I don't carry external oxygen, and have read of some insects being found (don't know by who) in the air as high as 12,000 feet.  I don't like the idea of sucking bugs into my engine and I''m not sure the gain in MP/speed is worth taking the chance of unfiltered air.

I admit that I can be a bit conservative.

[PTK]

All of you guys arguing about ram air, I know in a J  RAM air is useless.  I plan to remove mine at some point.  Mooney has a Service Instruction to do this.  It cleans up the front.  The one thing holding me back is weather or not it would be wise to install landing light in the wing and cleanup that hole in the front at the same time.  Any ideas are always appreciated. 

http://www.mooney.com/images/pdfs/si-pdf/sim20-93.pdf

[podair]

unfortunately Ram Air makes a significant difference on my M20F, at least an extra 1in if not 1.5in of map, and that is despite having a K&N filter which improves things a little apparently. I always close it below say 3k and when entering cloud. At low altitude , the map impact is not really an issue, but higher , it is. I normally fly at 10k, so I normally open it from around 5k onwards and leave it open. 

Also, I have sometimes noticed very mild rough running when just below cloud, I assume the ven

turi effect lowers the temps and the air reaches dew temp at that point, hence mild ice ? So whenever I am in conditions of high moisture in the air or between layers, I close it too. Am I reading this right or am I being paranoid?

 

[Piloto]

Quote: allsmiles

All of you guys arguing about ram air, I know in a J  RAM air is useless.  I plan to remove mine at some point.  Mooney has a Service Instruction to do this.  It cleans up the front.  The one thing holding me back is weather or not it would be wise to install landing light in the wing and cleanup that hole in the front at the same time.  Any ideas are always appreciated. 

http://www.mooney.com/images/pdfs/si-pdf/sim20-93.pdf

[jelswick]

I Never, Ever, EVER fly through cloud with the ram air inlet open!  My M20J had the Service Instruction M20-93 Ram Air Removal Retrofit already done when I bought it, so not even an option for me...  

[jelswick]

And Lew, I don't think you're being too conservative.  I know I've seen on Discovery, Animal Planet or Nat Geo where some insects and spiders migrate by flying or hitchhiking a ride in air currents at pretty high altitudes (don't remember their preferred flight levels).  Weather baloons have also found insect skeletons as high as 45,000 feet and I'm assuming our engines don't really care if they're ingesting a live bug or just his skeleton.