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Helicopter flying in the rain


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I am new to helicopters. I fly fixed wing in the rain without much problem. I usually reduce the propeller speed to reduce erosion. Taxiing is troublsome as I have no wipers. At about 60 knots the canopy clears and the rain only reduces visibility slightly.

 

I have only two flights during my helicopter training when rain was encountered. One time was just light misting that lasted only a few minutes. My instructor told me that helicopters fly in the rain. The second time I was practicing at the north helipad. The wind was gusting and reversing. The helicopter canopy became very opaque during hover phase. The rain became rather intense. The visibility dropped to about 1/2 mile. My instructor did not like this and we air taxiied back to the hangar.

 

How much rain is ok for a R22? Will rain remove all of the paint on the rotor leading edge? What are the other risks of flying a helicopter in the rain?

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The biggest concern is the descending tail-rotor blade. The ascending blade hits the blunt end of the rain drop, but the descending blade hits the pointy end which is much more damaging. :)

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I had students that basically thought the helicopter would "Melt" if we flew it in the rain. Their fixed-wing instructors had it drilled into their heads that any rain is very bad and you should not fly in it. "You should definitely avoid flying helicopters in the rain" is what I was hearing a lot.

Light-medium rain is okay, but heavy I would avoid. Also heavy rain usually means a bad storm and you probably should not be flying anyway.

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the descending blade hits the pointy end which is much more damaging. :)

 

interesting, i never knew that rain drops had a pointy side.

 

I have flown 300's in heavy rain for over an hour at a time & it leterrally rips the paint off of the T/R blades & doesn't do much good for the paint on the mains either. Remember to grease everything as soon as possible after flying in the rain too.

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It's too much rain when the visibility is below minimums. Visibility and ceiling are the limiting factors to flying in rain. The tail rotor and the main rotor get hit about the same, because the end of both are near supersonic in cruise flight, moving through the air at about the same speed. Heavy rain will cause some erosion, and roughen the leading edges, but it's not a major factor. Mechanics don't like it much, since they may have to file the blades to smooth the airfoil.

Hovering in heavy rain can cause the inside of the windshield to fog up. Years ago, before we had heaters in the 206s offshore, I flew a contract where I did well over 100 takeoffs/day, just hopping from platform to platform, many just a few hundred feet apart. When it rained, I often had to carry someone in the front seat with a roll of paper towel to wipe the windshield for me, because everyone who got in was wet, and it fogged up so badly that I couldn't see anything. I was taking off and landing constantly, and didn't have time to wipe and hover, so he did it for me.

 

Other than that, rain has little effect.

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Wow I gotta say U guys are A bunch of wimps! U need to fly in Seattle for a few years! U just paint your blades more often in SEA.

and the MR has a way Higher Tip speed than the TR!

 

 

Eh.

 

Less than 100 FPS difference between MR and TR tip speed on the R22 and R44. Also, don't start believing you can fly anything in any wx, you'll just be another sad IIMC or CFIT story my family tries to use to guilt me into getting a "real job", and tourists use to justify not taking that tour flight that keeps a good company in business. Keep that cowboy BS off the forums and out of your head, and you'll live to appreciate it.

 

Nick

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Eh.

 

Less than 100 FPS difference between MR and TR tip speed on the R22 and R44. Also, don't start believing you can fly anything in any wx, you'll just be another sad IIMC or CFIT story my family tries to use to guilt me into getting a "real job", and tourists use to justify not taking that tour flight that keeps a good company in business. Keep that cowboy BS off the forums and out of your head, and you'll live to appreciate it.

 

Nick

 

 

I have to agree. The egocentric name calling to make a pilot feel inferior for not flying in the same conditions, or do the same mach BS stuff is a detriment to the industry. Never bash another pilot for flying within their own skill level. This is the quickest way to kill friends.

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Mechanics don't like it much, since they may have to file the blades to smooth the airfoil.

 

 

Hovering in heavy rain can cause the inside of the windshield to fog up.

 

What helicopter has blades that you can file? - i've never heard of such a thing for helicopter blades, but airplane propellers - yes. All of the metal blades i have worked with are sheet metal wrapped around an extruded alum spar,,, & once the sheet metal has eroded? - time to send to authorized blade shop OR scrap the blade.

 

I've had the windshield fog up on me just hovering the ship back from the hose after a wash--NOT a fun situation ! Amazing how fast your brain reacts when your eyes are gone OH S * * T !!!! :o

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Pokey, "file" may not be the word but "dress out" with a very fine grain file! Fenestron blades can be "dressed out or filed" as can many/most blades that have a metal leading edge. Check the MM for allowances!!!!!!!

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Pokey, "file" may not be the word but "dress out" with a very fine grain file! Fenestron blades can be "dressed out or filed" as can many/most blades that have a metal leading edge. Check the MM for allowances!!!!!!!

 

 

 

Yes Mikemv, you are right----ALWAYS check the MM for acceptable repairs. I've been woking on & rebuilding helicopters for over 20 years ( mostly 269's). Worked on alot of Bell products, aerospats ( back in the old days) & even Enstroms.. About the only ships i have ever had any significant blade problems with were on the 269's, and i dont ever recall seeing anything in the manual about removing any metal from the leading edge to "clean it up" I'm just curious as to what models have field repairs w/ regard to dressing ? I know that the skin of the 269 blades is only about 0.025 inches,, which can be removed in a matter of swoops with even a fine file.

 

43.13 addresses the proper dressing out of propeller knicks & dents--but? that is a solid piece of forged aluminum,,, is that how the fenestron blades are manufactured? ( i was close to a fenestron unit once--but?- i guesss i didnt pay enuf attention)

 

I once had a problem w/ abrasion wear completely thru the leading edge of a 269 blade,, was no repair in the MM. Called Schweizer & they sold us a new blade ( $11,000 then,, but now $16,000) but? just for fun my customer requested that we send the old blade to CTI & see what they said. They cut out the eroded section, cleaned up the corrosion, added a patch, repainted the blade, & gave us a "return to service" tag/approval--based on THEIR approved repair procedures. Moral of this story?---Just because it isnt in the MM, doesnt mean that an approved repair station cant fix it.

 

on side note? i would never take a file to a $16,000 piece of 12 foot long aluminum ! ;)

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You need to read the maintenance manuals, pokey. It's allowed, and done all the time, on most models. I saw a mechanic take a hacksaw to a blade a few times. There was a bulletin that allowed removal of the inboard trim tab on 206L blades, and my employer did it. I walked into the hangar, watched the hacksawing for a little while, and left, afraid to look back. In the end, it was all good. There doesn't need to be a lot of metal removed from the leading edge, just smooth down the roughness that comes from the rain. It gets very pitted eventually, and they need to be dressed on scheduled inspections, or the lift is affected.

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You need to read the maintenance manuals, pokey. It's allowed, and done all the time, on most models. I saw a mechanic take a hacksaw to a blade a few times. There was a bulletin that allowed removal of the inboard trim tab on 206L blades, and my employer did it. I walked into the hangar, watched the hacksawing for a little while, and left, afraid to look back. In the end, it was all good. There doesn't need to be a lot of metal removed from the leading edge, just smooth down the roughness that comes from the rain. It gets very pitted eventually, and they need to be dressed on scheduled inspections, or the lift is affected.

 

 

Well, it isn't the metal that needs to get dressed but the paint. On the Robinson's they would recommend emery cloth to smooth out the paint at the tips. But to file the metal is something I have never heard of. These aren't prop tips that get rock nicks in them.

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I saw a mechanic take a hacksaw to a blade a few times. There was a bulletin that allowed removal of the inboard trim tab on 206L blades, and my employer did it.

 

 

Yip, even in the 300 manual, they have a procedure for filing out cracks in the trim tab & even allow the complete removal of it. Just need to be careful as to not crack the bond of the trailing edge. I've worked on a ship once that had 1 blade w/ out the tab ( i wasnt the one to remove it tho)----what a pain to track & balance that one ! ( think the customer eventually sold the blade & got another w/ the tab still on it)

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No, it's not just the paint. The leading edge, unpainted, gets very rough and pitted. This leading edge is dressed to smooth it. The paint is generally untouched, at least on the models I've flown, including the BH206 series, AS350, BH412, & SK76. The main rotor blades on all of them get pitted and rough when flown through rain, and can be dressed smooth. I've never seen the paint affected.

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Heavy rain + 500 = little or no paint on 1/2 main rotor leading edge, then the pitting follows real quick, smooth & paint ASAP

 

 

pretty much the same w/ the 300, i like the blades w/ the modified 36 inch long abrasion strip--thats where most of the abuse takes place.

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You can file the leading edge on metal rotor blades......It's legal and happens all the time. It's like adding 50-100hp when you're done.

 

But when it comes to the regs, "PROPELLERS" are NOT the same as "ROTOR BLADES". Propellers carry their own log books and are usually restricted that only repair stations can work on them. Rotor blades are considered part of the airframe when it comes to helicopters.

 

Ever seen a S61 blade? It's like Legos. The trailing 2/3's of the blade comes off in sections making repairs easy. I've seen some old maintenance manuals for the some helicopter (Hiller maybe?) that has blade repair procedures. How cut out the damaged area, make a patch, feather it out, etc. You would NEVER see that today.

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You can file the leading edge on metal rotor blades......It's legal and happens all the time. It's like adding 50-100hp when you're done.

 

But when it comes to the regs, "PROPELLERS" are NOT the same as "ROTOR BLADES". Propellers carry their own log books and are usually restricted that only repair stations can work on them. Rotor blades are considered part of the airframe when it comes to helicopters.

 

Ever seen a S61 blade? It's like Legos. The trailing 2/3's of the blade comes off in sections making repairs easy. I've seen some old maintenance manuals for the some helicopter (Hiller maybe?) that has blade repair procedures. How cut out the damaged area, make a patch, feather it out, etc. You would NEVER see that today.

 

Well with a Hiller you just run down to Home Depot and grab a 2"x12"x20' pine board and bolt it on... :P

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