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  #11  
Old 02-17-2013, 07:05 PM
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dmaib dmaib is offline
 
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I have flown through some pretty heavy rain a couple of times and have never had the engine give any indication of a problem. I did, however, have to have my MT propeller repainted. I am much more conservative about rain these days.
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  #12  
Old 02-17-2013, 08:06 PM
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Saber25 Saber25 is offline
 
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With all due respect, why fly in moderate to heavy rain or for that matter a red radar return in a single engine airplane? Moderate to heavy rain can lead to bigger problems quickly. When getting paid to fly in such conditions the Ops manual for a jet advised caution and circumnavigate red returns.
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  #13  
Old 02-17-2013, 08:28 PM
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Quote:
Originally Posted by pierre smith View Post
Dan, I may just do the water hose trick but how do I relate that to either moderate, or heavy rain?
Apparently if the the paint stays on it is like moderate rain. If the paint comes off it is like heavy rain. If it eats metal you have landed on a lake
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  #14  
Old 02-17-2013, 09:08 PM
GEM930 GEM930 is offline
 
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Not sure how much this helps as I do not have any exact numbers, but I experience a situation when I believed my filter sucked in enough rain to effect engine performance. My 6a has an electronic fuel injection system that uses a manifold pressure sensor (along with air tempature and rpm) to calculate the fuel delivery. My filter and air box were the standard units provided by Vans for a carbureted plane at that time. I was flying in some pretty heavy rain and noticed the rpm started to smoothly drop, as if I was closing the throttle. I do not remember for sure, but I believe I lost around 150-250 rpm pretty quickly. I was able to regain most of the loss by going WOT, but the plane was certainly not performing like it was WOT. Since the EFI uses manifold pressure and the loss in power was very smooth (like slowly closing the throttle) I sumized the filter was getting water logged. After the filter dried out never I had that problem again. I am in the process of installing the same system on a new engine and have decided to build a new air box with an alternate opening that bypassed the filter all together because of that incident.
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  #15  
Old 02-18-2013, 04:34 AM
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pierre smith pierre smith is offline
 
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Quote:
Originally Posted by Saber25 View Post
With all due respect, why fly in moderate to heavy rain or for that matter a red radar return in a single engine airplane? .
Hans, the radar returns on the weather channel only showed mostly green with a few yellow patches, also confirmed by my 496 in flight.

Like you. I wouldn't even consider penetrating red areas....matter -of-fact, I was concerned about the yellow patches but I learned a valuable lesson...that a small bit of yellow is not really a problem. We were in a well-equipped airplane, with two IFR rated guys up front.

Best,
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  #16  
Old 02-18-2013, 05:43 AM
sailvi767 sailvi767 is offline
 
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I would avoid red returns if at all possible. My biggest concern however would be what is producing the rain. If this is convective activity then you need to be very careful. Lots of bad things can happen flying through or under thunderstorms and they can change quite rapidly. You as the pilot can't predict the change so if you choose to fly through or under or even near convective activity then your simply rolling the dice. Delta 191 in Dallas picked up what looked like a very small convective rain shower on final. A much smaller aircraft flew under it 1 minute before they did without issue. 1 minute later that small shower slammed a 400,000 lbs aircraft into the ground even though they still had plenty of energy and actually impacted the ground at 180 knots. They simply could not overcome the huge downdraft in the microburst. The smaller aircraft just seconds ahead reported a nice ride and no problems!
If I were flying a well equipped IFR aircraft through a warm front type of rain activity and there were yellow areas it would not give me a great concern. If on the other hand it was a front with convective activity a yellow return would scare the blank out of me! The delay in weather reporting could mean that yellow return is something very different when you get there. That does not even include what might happen with a lighting strike.
I remember looking at the weather on the day Pierre was flying and I think it was just a big warm front so I would have had no problems flying the route he did.

George
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  #17  
Old 02-18-2013, 06:15 AM
gongreg gongreg is offline
 
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Smile

Although flying into radar reds in a light plane is not fun and no one does it on purpose (hopefully!!!!), I think it is a great idea to know all there is to know about the behavior of the engine when flying in such very wet conditions.
that should give an idea of what to expect in case it ever happens. It can only help!
My 2 cents.
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  #18  
Old 02-18-2013, 07:32 AM
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Quote:
Originally Posted by gongreg View Post
....... I think it is a great idea to know all there is to know about the behavior of the engine when flying in such very wet conditions.....
Agree, and that was the point of the water hose suggestion; one test is worth 50 opinions. If spraying the prop is a bad idea, there are surely ways to rig a "water spray introduction device" directly to the air intake.

Maybe this....a length of vinyl tubing routed in via the cowl outlet, with a short length of crimped brass tube stuck in the end as a spray nozzle. Tuck the brass end under the rubber flap seal at the airbox entry. Calibrate water flow to some rough standard before installation, as in some degree of valve opening equals some quantity of water in a given time.



My own airbox was designed with an automatic alternate air door downstream of the K&N filter. It opens at a differential pressure of 3" H2O or less (0.2 Hg) and takes in hot air from the lower cowl volume. When it opens it lights an LED on my switch panel to let me know. I do not fly IFR, and with this system I don't worry about the level of rain which still allows easy VFR. If the filter becomes saturated with rain (or even ice) I expect a small power loss and a light to tell me why.
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Last edited by DanH : 02-18-2013 at 07:35 AM.
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  #19  
Old 02-18-2013, 11:46 AM
gongreg gongreg is offline
 
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Location: S?o Paulo Brasil
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Red face

I wonder if a one off test would cause all that damage to the prop. Maybe the life of a hard working float equiped DHC Beaver is real hard on the prop, but spraying it once for the purpose of this test... should it cause all that erosion, if any?

Last edited by gongreg : 02-18-2013 at 11:51 AM. Reason: spelling
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  #20  
Old 02-18-2013, 12:26 PM
rdoerr01 rdoerr01 is offline
 
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I was coming back from Canada one summer when at 8000 I was in the soup and it was raining pretty heavy. Everything was going along fine until I started to see my indicated airspeed dropping. It went from 145 Knots at cruise to as low as 105, all with the same power setting. At this point I was starting to worry and was about to pull the Alt Air figuring the air was being blocked by the rain, but since it is only resettable on the ground I instead ask ATC for higher and after about 10 minutes that was granted and I climbed up to 11,000 and then was out of the rain. It then took about 20 minutes for the filter to dry out and my airspeed took about 20 minutes to slowly recover back to 145 Kts.
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