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Serious LMH Blade Problem affecting us all !!!

Old 11-26-2006, 03:58 PM
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Default Serious LMH Blade Problem affecting us all !!!

I've heard comlaints before on this forum about Corona 120 Main blades cracking at the blade root under normal flying conditions for no apparent reason. I've been using an old set of main blades that I have been flying with for the past 2 years with no problems, I'm very carefull with my heli and dont crash, so I really dont buy blades that often. But my old blades needed to be changed because they had lots of stress cracks on the blade's plastic surface from age and lots of use. I took out a set of brand new blades in a package and after 5 flights the blade root just sheared off !

Are you guys still having this problem? or have I gotten a set of blades from a defective batch that was purchased months ago?

HAS ANYBODY NOTIFIED LMH ABOUT THIS HAZARD, WHICH COULD LEAD TO A PRETTY BIG LAWSUIT ONE DAY.......[X(]
Old 11-29-2006, 08:38 PM
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Default RE: Serious LMH Blade Problem affecting us all !!!

I have had two break already. One departed from the Heli, man did it move fast, and the other stayed on untill battery ran out.
Old 11-30-2006, 03:47 AM
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Default RE: Serious LMH Blade Problem affecting us all !!!

Gosh I've had really good luck. I've always used the green colored blades and I've crashed into trees and never broke a blade!

Too bad they don't make the transparent blades any longer.....

[]
Old 11-30-2006, 08:25 PM
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Default RE: Serious LMH Blade Problem affecting us all !!!

Well, at almost $10 a blade in addition to possibly getting my head taken off by these helis, Here's my solution! I've constructed something I call "BLADE BRACES" Cut from .032 Aluminum sheets, I constructed a Brace that wraps around the blade root so that if the root cracks at least theirs no possibility of the blade Flying off in mid flight, even if the blade root still fractures with the brace installed it won't come of the heli. I use aluminum because it's easy to cut and lighter. The brace wraps around the top of the blade and under were a bolt connects the top and bottom of the brace, drilling right into the blade surface. See Photos below! Also see the diagram of the basic BLADE BRACE Pattern.

Hope this helps you guys, at least now I can fly without being scared of my own heli.......

P.S. I've been flying with these BLADE BRACES for 1 year now. Some Blades don't even crack and some still do fracture, but the Blade stays on and all I do is glue the fracture lines with CA glue. the key is to wrap the brace tight along the blade root, you may even want to use a thinner aluminum to get that wrapping effect tight or use a more plyable material like soft copper!
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Old 11-30-2006, 09:25 PM
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Default RE: Serious LMH Blade Problem affecting us all !!!

cool idea flying fish!
Old 12-17-2006, 10:05 AM
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Default RE: Serious LMH Blade Problem affecting us all !!!

That is a great idea there, i am constructing some as we speek. I too have had a problem with the root cracking on the edge there, the white blades badly for some reason. I have a set of the transparent blue on there now and all good for the last 6 months...so far.
Old 12-17-2006, 01:17 PM
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Default RE: Serious LMH Blade Problem affecting us all !!!

In some cases the blade root may still crack, but all the peices stay together then you glue it together again. I'm now finding it's a good idea to put some kind of cushy gasket between the blade and the metal brace, Im using Black electrical tape as a gasket material. In any case, if the blades still cant be saved or used again, at least the blade wont fly off in your face. that's my main concern for you guys. how can you fly with confidence if your scared!!! Here's another hint, if you dont have a blade brace installed and your flying while a blade root cracks in mid flight, but does not break off completely, you will know because you will hear a change in sound. The normal flutter sound may change to a higher or louder fluttering pitch sound. If you hear this change in pitch, LAND IMMEADIATLY and check your blade roots!.....[X(]

What's good about the blade braces, is that you only have to make them one time, so take the time to construct them well. If you snap a blade due to a crash, or if you can no longer salvage a blade due to a bad root crack, all you do is remove the brace from the old bad blade and reinstall them on the new blades!
Old 12-17-2006, 06:31 PM
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Default RE: Serious LMH Blade Problem affecting us all !!!

Right on, i made a set out of brass sheet and had a chance to try them out today before the snow storm hit and no problem not even a need to rebalance the blades.

P.s. I fly with my blades locked down and allways attributed the cracking to that. Do you fly with yours locked or do you swing them?
Old 12-18-2006, 03:33 PM
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Default RE: Serious LMH Blade Problem affecting us all !!!

I lock them down, I find that if they swing to much it causes a bad vibration in the rotor head, even without the braces.
P.S. Try not to fly in extreme cold. The plastic blades will become more brittle in cold weather and may have a greater chance of cracking!

I HATE COLD WEATHER !!!!!!!.........[:@]
Old 12-18-2006, 06:20 PM
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Default RE: Serious LMH Blade Problem affecting us all !!!

Hea thats for sure, i moved to a bad place for that.I fly all year and take advantage of the cold thick air (i fly at 5000ft ASL) when i can. Got ski's and float's for every thing, i just started to notice the crack's after many hours on those blades. It seem's to take some time to happen.
Old 12-21-2006, 08:11 PM
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Default RE: Serious LMH Blade Problem affecting us all !!!

Would be interesting to know:

How you're spooling up/down the rotor.
How tight the lead/lag bolts and flapping bolts are.
How you're transporting the heli.
What blade pitch you're using.
Photographs of the blade cracks.

Old 12-21-2006, 10:52 PM
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Default RE: Serious LMH Blade Problem affecting us all !!!

(1)The only way you can with the LMH slow and smooth

(2)flaping bolts loose,lead lag locked down like most of us who fly fixed pitch

(3)in the back of my full size GMC van on the bed in the back with foam blocks to keep it from slideing around

(4)six dot all around i fly at 5000ft ASL

(5)i can shot some photos, it will take a few, but thay start at the leading edge 15mm from the mount end of the blade and work in (very hard to see untill dirt gets in and colors it)

Heli and blades are 5 years old and i am an advanced/expert pilot and fly`this' heli 2-3 times a week on average.
Old 09-01-2008, 09:50 AM
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Default RE: Serious LMH Blade Problem affecting us all !!!

Hi All,

the blade problem finally strike me []. I just purchased a new pair of blades (and it is the white blades). i ran it on nitro and all went well. however, the blade just dropped overnight when the other is cracking. lucky that i didnt happened mid air. i went back to use the old shorter blade which is actually more durable. i noticed that the shorter old blades are more flexible actually.

looking at older posts, i think by all means avoid getting white blades! some say green has no problem. any other experience with other color?

thanks

Lawrence



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