Flying Through Rain

Tantalum

Tantalum

Final Approach
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San_Diego_Pilot
Been raining a lot here in San Diego the last few days, which got me thinking... has a piston GA plane ever lost power due to too much water going into the air induction system? Looking at a 172 the air filter is right there on the front of the plane.. from there it goes to the carburetor, and up into the engine..

Looking at the diagrams for various other engine induction systems there doesn't seem to be any real effort made to keep water out of the system

So, does even torrential rain downpour not pose enough of a risk of water intake to the cylinders to hydrolock it, or "put the fire out" so to speak? I know carb heat can cause some roughness due to the ice melting.. so this seems to at least be theoretically possible, but wondering if it has ever actually taken place
 
It’s never happened to me, and I’ve flown through some very heavy precipitation. I’ve never heard of it either.

Remember that even in a downpour it’s still a lot more air than water. It will erode the paint on the leading edge of the wings some.
 
172 also has an updraft carb, so the water droplets would have to fight gravity as well.
 
Ted DuPuis said:
It’s never happened to me, and I’ve flown through some very heavy precipitation. I’ve never heard of it either.

Remember that even in a downpour it’s still a lot more air than water. It will erode the paint on the leading edge of the wings some.
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What about the prop blades?
 
Water is H - 2O, it burns rather well.

ADI is proof.
 
Alt air. But I have never needed it. Or carb heat, which technically is alt air. Heavy rain can blast the paint off your plane.
 
asicer said:
172 also has an updraft carb, so the water droplets would have to fight gravity as well.
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On a 172 the air's speed thru the airbox isn't fast enough to carry the water up into the carb. So it simply drains out the drain provided
 
Tom-D said:
On a 172 the air's speed thru the airbox isn't fast enough to carry the water up into the carb. So it simply drains out the drain provided
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A plane like a Cirrus seems to be more "direct" with the air inlet up in the cowl and piping its way through the turbos / engine, with no carb and no drain that I've found when the cowl's been off. The alt air on a Cirrus is "automatic" it just flips open with a magnet, so.. hope for the best in rain I guess?? #parachute ?

It has happened to jets though, right? So it seems the possibility exists

Would be interesting to put one up in one of those turbine test stands and see how much water it takes to kill
upload_2019-2-2_22-11-27.png
 
Tantalum said:
A plane like a Cirrus seems to be more "direct" with the air inlet up in the cowl and piping its way through the turbos / engine, with no carb and no drain that I've found when the cowl's been off. The alt air on a Cirrus is "automatic" it just flips open with a magnet, so.. hope for the best in rain I guess?? #parachute ?

It has happened to jets though, right? So it seems the possibility exists

Would be interesting to put one up in one of those turbine test stands and see how much water it takes to kill
View attachment 71301
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You lost me, how does that apply a 172?
 
AKBill said:
Was just thinking about a fellow that parked in the row behind me in Juneau he had a Piper twin. Well he took 2 friends for a ride. It sounded like he shut one of the engines off to demonstrate how to restart the engine in flight. Battery was low and it would not start the engine. Instead of flying 20 miles to Haines, AK and land on a 5000ft runway he chose a beach.
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That's ridiculous. I'm wondering, how was the battery too low? Did only one engine have an alternator on this twin? Or is the alternator's output too low to sufficiently charge / start an engine?

Tom-D said:
You lost me, how does that apply a 172?
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Just wondering how much "rain" it would take to actually kill the engine, but sounds like it may not be possible given the updraft carb design. On a plane with a different intake design it'd be interesting to test it out, just to see if it was possible, and if so, how much water would it take..
 
Tantalum said:
That's ridiculous. I'm wondering, how was the battery too low? Did only one engine have an alternator on this twin? Or is the alternator's output too low to sufficiently charge / start an engine?
.
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Is there no accumulator on the twin Piper which would allow an air start?

I can confirm that rain will do an excellent job of removing paint from leading edges of wings and painted propellers. I had an instrument student with a C210 and we subjected it to some heavy rain on his long cross country. May as well have been sand.

Heavy CB but no rocks, lightening or reports of ugly turbulence. It did get pretty dark for a while.

I can remember thinking I wished I had a hood on too.
 
Tantalum said:
That's ridiculous. I'm wondering, how was the battery too low? Did only one engine have an alternator on this twin? Or is the alternator's output too low to sufficiently charge / start an engine?
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I agree it's ridiculous. I can't answer your question now but I will try to give you a better answer...:(
 
Yep, prop blades.. seems to me a propeller spinning at 2,000 plus probably makes a hell of a centrifugal water separator. But then I could be all wet.
 
I’ve flown in pretty heavy rain a few times. One time at night many years ago while working on my instrument rating. I remember doing constant rate and speed climbs and descents. Over an hour it rained about a half inch.

Another time cross country at night in the Bonanza, rain was so heavy that ATC was advising heavy precipitation, and when I glanced out at the wing tips the strobes made it look like a snowstorm. But the air was smooth as glass and the IO520 just purred along.

I have to say I wondered a bit the same question as Tantalum. So I asked an instructor about it; he said he’d never heard of rain stopping an engine.

Now, induction ice, that’s a different story altogether.
 
We re to avoid heavy precipitation in the 38 due to paint and fiberglass considerations. At our standard 300kcas the paint will peel above moderate precip. Normally slowing to holding speeds (250kcas) does the trick while getting out of it.

As to water stoppage, not on updraft induction systems. I was once scared enough going thru yellow on my adsb display where the precipitation was strong enough I thought the trusty ol o-320 was gonna quit. I put carb heat on for the duration, though it was likely placebo, while I prayed to all the denomination dieties and promised never to risk my life for the sake of kitty if they let me survive this one (I never did do it again, but that's because I married the kitty and thus have no use for such antics anymore lol).
 
Ice is different than rain because it can block the air inlet. It’s never caused me problems but it can.
 
Dana said:
Not in my experience... it takes the varnish right off the prop.
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Or if it’s fiberglass, strip the fiberglass right off the prop. Totally ate up the outboard leading edges on my Catto years ago in moderate rain. Found out later that Catto recommends no more than 2200 rpms in rain.
 
65D3C160-DC89-4063-93A4-EE8A4F99AE88.jpeg Another anomaly for the canard guys is pitch instability in rain. Some don’t have it, some do. Just flew through light rain on Friday and soon as it hit, my nose pitched down a couple of degrees. A little annoying but once established and retrimmed in the rain, it’s a non event. It’s the in and out that’s the problem. Made for a pretty flight.
 
Carb ice is more likely in rain. Can't have all that water in the air without the relative humidity going up.
 
Tantalum said:
Been raining a lot here in San Diego the last few days, which got me thinking... has a piston GA plane ever lost power due to too much water going into the air induction system? Looking at a 172 the air filter is right there on the front of the plane.. from there it goes to the carburetor, and up into the engine..

Looking at the diagrams for various other engine induction systems there doesn't seem to be any real effort made to keep water out of the system

So, does even torrential rain downpour not pose enough of a risk of water intake to the cylinders to hydrolock it, or "put the fire out" so to speak? I know carb heat can cause some roughness due to the ice melting.. so this seems to at least be theoretically possible, but wondering if it has ever actually taken place
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There is a note in the 172 POH about using carb heat as an alternate air source when flying in heavy rain to prevent water ingestion.
 
If you taxi a float plane on a choppy windy day there are times when the air intake ingests way more water than rain can provide. I’ve never had one quit.
 
All I’ve seen in mine is paint getting chipped off and water coming in all those little leaks

Gary
 
Rgbeard said:
Airliners make crappy gliders, but the pilot of TACA 110 did a pretty good job.
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That's actually what got me thinking.. if it can kill a turbine, is there a risk to us piston guys? Maybe an updraft Skyhawk is safe, but about planes with a more direct inlet, like a Cirrus. Unsure how the Bonanza induction works..

hindsight2020 said:
kitty
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...oh the things we do... for "that" ! haha "is that a pirep for severe ice? Hopefully the FIKI works!"

Velocity173 said:
canard guys is pitch instability in rain. Some don’t have it, some do. Just flew through light rain on Friday and soon as it hit, my nose pitched down a couple of degrees. A little annoying but once established and retrimmed in the rain, it’s a non event. It’s the in and out that’s the problem. Made for a pretty flight
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Interesting, what causes this? Does the water change the airflow on the canard.. is it the "weight" of the water hitting the nose pushing the nose down?

asicer said:
ingesting water is good at cleaning the carbon off of pistons and valves
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At least there's a silver lining in there I can think about if my engine ever quits in heavy rain
 
Tantalum said:
That's actually what got me thinking.. if it can kill a turbine, is there a risk to us piston guys? Maybe an updraft Skyhawk is safe, but about planes with a more direct inlet, like a Cirrus. Unsure how the Bonanza induction works..


...oh the things we do... for "that" ! haha "is that a pirep for severe ice? Hopefully the FIKI works!"


Interesting, what causes this? Does the water change the airflow on the canard.. is it the "weight" of the water hitting the nose pushing the nose down?


At least there's a silver lining in there I can think about if my engine ever quits in heavy rain
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It’s a disruption in the airflow. What’s strange is, some pitch down and some up depending of the type of airfoil. Extreme contamination with bugs can cause issues as well.
 
Velocity173 said:
Or if it’s fiberglass, strip the fiberglass right off the prop. Totally ate up the outboard leading edges on my Catto years ago in moderate rain. Found out later that Catto recommends no more than 2200 rpms in rain.
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No ill effects in rain on my Catto 2-blader, but I have the optional nickel leading edges.
 
SoCal RV Flyer said:
No ill effects in rain on my Catto 2-blader, but I have the optional nickel leading edges.
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Yeah, that’s exactly what I’ve been telling myself for the past 7 years that I need the nickel leading edge.

You wouldn’t believe what the prop I’m flying on right now looked like when I landed at Velocity. Looked like mice had eaten about 1/4 inch of the leading edge of the prop. Outstanding customer service by Catto by the way. I email them a question and ether he or his daughter get back to me in hours.
 
Velocity173 said:
Outstanding customer service by Catto by the way. I email them a question and ether he or his daughter get back to me in hours.
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I second that. Such a solid company with nice people, and Craig's expertise in prop design is amazing.
 
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