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All Forums >> RC Helicopters >> Century - Predator, Hawk IV, Falcon, Raven >> hawk clutch question
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hawk clutch question - 9/23/2006 11:48:58 PM   
n4paj


 

Posts: 2
Joined: 6/27/2002
From: Boaz, AL, USA
Status: offline 		Hello

First a little history. I had been flying the hawk for several gallons of fuel. I am learning so all flight have been hover or slow flight. It is a Hawk sport upgraded to a pro. I went to the flying field and flew, the wind was insane and the rotor was going wide open, way to fast for wooden blades. I got it slowed down and flew 3/4 of a tank and then let it sit until the wind calmed down. During the wait the engine flooded and during the start I ran the clutch into the bell and jammed it up. So I was through for the day.

Fixed the clutch problem but now the clutch stays engaged all the time, it has a plastic bell. I can turn it by hand and it is free, but it seems like if the engine has enough rpm to idle it will spin the main blades. I have a new clutch bell on order, but can't understand what is wrong with this one? Why did the main blades speed up, was it the wind? Did I ruin the clutch assy with my failure to deal properly with a flooded engine? Beats me?

Thanks for the replies
       Post #: 1

RE: hawk clutch question - 9/25/2006 2:25:39 AM   
lyk2fly


 

Posts: 357
Joined: 7/1/2003
From: Turtletown, TN, USA
Status: offline 		Hi, I don't see how the wind sped the main rotor blades up...that should be dictated by your pitch/throttle curves...and I've dealt with flooded engines mucho times and never effected the clutch. If the washer is in the right place and the bearing in the clutch bell is free then maybe the clutch shoe was accidentally spread. This would cause premature engagement of the clutch. I would inspect the shoe very carefully looking for a possible crack as well. I hope this helps.
Mark

(in reply to n4paj)
       Post #: 2

RE: hawk clutch question - 9/26/2006 11:48:05 AM   
Lifes a Drag



Posts: 957
Joined: 1/10/2003
From: La Habra, CA, USA
Status: offline 		Is your motor aligned correctly & not rubbing the clutch to the bell somewhere?

(in reply to lyk2fly)
       Post #: 3

RE: hawk clutch question - 9/28/2006 3:17:02 AM   
n4paj


 

Posts: 2
Joined: 6/27/2002
From: Boaz, AL, USA
Status: offline 		Thanks for the suggestions. I checked the clutch and it appears to be ok. There isn't very much room to adjust it, it looked fine to me. There was one small spot where it dragged the bell for just a fraction of an inch. I replaced the bell and now it is tight, tight. I guess I need to burn the outer surface off the lining. Is it ok to rev up while holding the head? How long to run it before testing? I want to free it up, not burn it up.

(in reply to Lifes a Drag)
       Post #: 4

RE: hawk clutch question - 9/28/2006 3:51:44 AM   
lyk2fly


 

Posts: 357
Joined: 7/1/2003
From: Turtletown, TN, USA
Status: offline 		Hi...I just replaced my bell also....due to crash damage to the gear. Mine is TIGHT too. I'm going to proceed with caution but I do imagine that you would hold the rotor head with the engine a high idle....to wear the bell lining to proper clearances. I'm still waiting on a tail boom...but other than that I'm ready

(in reply to n4paj)
       Post #: 5

RE: hawk clutch question - 9/28/2006 8:01:58 PM   
syclic



Posts: 1030
Joined: 2/8/2002
From: rural, AB, CANADA
Status: offline 		When you started it and had the "run-away" that damaged the bell/liner. I will bet that you also damaged the clutch itself. The clutch wings are "sprung" (they now splay out further then they should).

With any heli, whenever you have to replace the bell, you should also replace the clutch, because it is almost always "sprung" at that point.

< Message edited by syclic -- 9/28/2006 8:03:05 PM >

(in reply to lyk2fly)
       Post #: 6

RE: hawk clutch question - 10/1/2006 7:14:35 PM   
n4paj


 

Posts: 2
Joined: 6/27/2002
From: Boaz, AL, USA
Status: offline 		I ran it in yesterday. No way was any kind of idle going to spin it up. It took WOT to burn it in. I didn't like doing it and the smell was pretty bad, but it freed right up and now it idles with the blades sitting still and picks right up on rpm increase and fly fine( no slippage I can detect)

I should have just freed the original clutch up and or when I replaced the bell I should have replaced the clutch too because it is most likely too open. But theses will get a visit the next time I do maintenance or crash repair. Right now I see no need to worry about it as it is working correctly.

By the way the original over-rev was caused by a slipping pitch servo arm causing almost no pitch at full rpm. That has been corrected and I think the cause for it was turning on the radio on with the blades still in the transport holder, not a good thing to do.

Thanks for all the help. If there is a way for a novice to screw something up I will find it pretty quick.

(in reply to syclic)
       Post #: 7

RE: hawk clutch question - 10/1/2006 9:56:49 PM   
lyk2fly


 

Posts: 357
Joined: 7/1/2003
From: Turtletown, TN, USA
Status: offline 		Hi...I put mine back in the air yesterday and today. Yesterday was mainly spent finding other problems that the crash had caused...like the clunk loose from the fuel intake line....stupid little things that could cause BIG problems. My clutch also freed up after about 2 tanks of fuel....that was a relief! Today was sweet flying...even some wicked stall turns but no inverting....I'm going to fly several tanks thru before I get back to that.....just to be sure all is well with the machine. BTW...I agree with syclic also...that the best approach would be to replace the clutch shoe when replacing the bell. One more thing....after researching that much damage is done when a heli "chicken dances" after a crash if the throttle cannot close and knowing that mine was wide open after my crash because the throttle ball link came loose prompted me to invest $.25 for a spring to be used as a throttle return. If the servo jams the spring would not help much but if the links pops off....at least the engine will be stopped.

(in reply to n4paj)
       Post #: 8

RE: hawk clutch question - 10/2/2006 3:19:21 AM   
n4paj


 

Posts: 2
Joined: 6/27/2002
From: Boaz, AL, USA
Status: offline 		Good deal, glad you are back flying. Did you just fly to get the clutch free or did you also burn it a little to get it free? Spring sounds like cheap insurance, do you know why the link jumped off?

(in reply to lyk2fly)
       Post #: 9

RE: hawk clutch question - 10/2/2006 12:18:59 PM   
lyk2fly


 

Posts: 357
Joined: 7/1/2003
From: Turtletown, TN, USA
Status: offline 		Hi....Yes I held the blades and kept the engine at a fast idle....eventually the clutch would seize....then I would free the clutch by turning the blades back wards. After several times the clutch loosened up. The ball link popped off due the a very bad crash.....the heli was a mess with the engine nearly wide open....when I arrived at the heli I put my hand over the muffler to stall the engine...but other than stripping the clutch bell gears, no harm was done that I can see. I've been flying for 4-5 years...and I'm still learning....and I still absolutely love this hobby!!! I hope all goes well with your heli experience.
Mark
P.S. I did change that ball link also!

(in reply to n4paj)
       Post #: 10

RE: hawk clutch question - 1/29/2008 3:45:23 AM   
loveforair


 

Posts: 4
Joined: 1/29/2008
From: Georgetown , TX, USA
Status: offline 		Hello Anyone/Everyone I have read all these "clutch forums" and i just need to know one thing... should the clutch be touching the pads when installed (normal position without engine running)? I crashed my Centrury Hawk Pro a few weeks back and replaced all of the damaged parts. everything that broke is now ready to fly again. When the heli crashed, the throttle reved up to full throttle due to the ball link coming off....the clutch arms bent out. In addition to all my repairs to the rest of the heli, i took the engine and clutch/bell assembly off to inspect it. I took the arms of the clutch and pushed them back paralell to the gap. i bought some pads for it also, but they are the same size as the ones already on the bell. should i replace the pads anyways and is that ok to just bend the clutch arms back like that? i don't want to be flying and have the clutch fail or somethin like that, you know ......

(in reply to lyk2fly)
       Post #: 11

RE: hawk clutch question - 1/30/2008 1:34:52 AM   
lyk2fly


 

Posts: 357
Joined: 7/1/2003
From: Turtletown, TN, USA
Status: offline 		Hi, I would try spinning the rotor assembly by hand to check for drag. If there is resistance then there is not enough clearance between the bell and shoe. The final check is to start the engine and see if the blades remain disengaged with the engine at idle. If it passes these tests then I would put that bird back to flying.
I hope this helps,
Mark

(in reply to loveforair)
       Post #: 12

RE: hawk clutch question - 1/30/2008 2:43:44 AM   
loveforair


 

Posts: 4
Joined: 1/29/2008
From: Georgetown , TX, USA
Status: offline 		EVERYONE READ THIS ONE!!! Thanks mark, i'll give it a try! hey, and has anyone heard of rotor bearings dislocating,because after my "post crash inspection", i found the cause of the crash....well obviously it was something in the tail section because it came barrelling down spinning like a ceiling fan, but faster... at first, i thought it was because of a crack in the carbon fiber tail rotors and then the just shattered eventually, but the innards of the two pivoting bearings for the tail rotor were still snug to the assembly . It was like the two blades, lets just say "embarked" from the choppers simontaioniously due to the bearing slipping off the balls and leaving the stationary part of the bearing (the part that the bolt fastens to) still on the rotor assembly and the rig and balls to go flying off....THIS IS KIND OF SCARY TO ME...how do i know that the main rotors won't do this....or if the tail blades will sling toward me again. A bit discerning??????????

(in reply to lyk2fly)
       Post #: 13

RE: hawk clutch question - 1/30/2008 3:08:23 AM   
lyk2fly


 

Posts: 357
Joined: 7/1/2003
From: Turtletown, TN, USA
Status: offline 		Wow!!!! I've never experienced a failure with the tail rotor on the Hawk (mine is a Hawk IV). I have had tail rotor failure on the Lite Machines I learned on and also on a Piccolo Pro. I would be getting to the bottom of that problem if I were you!!
Mark

(in reply to loveforair)
       Post #: 14

RE: hawk clutch question - 1/30/2008 4:06:20 PM   
loveforair


 

Posts: 4
Joined: 1/29/2008
From: Georgetown , TX, USA
Status: offline 		Ya, i mean that's pretty scary though. I'm gonna take it to my local hobby shop and see what they say. I know the owner personally and he flys raptors so he should know if that's really bad or if it was just a part that i should have replaced. it's soo wierd though, you know what i mean? both bearing just shattered at the exact same time!!! the ONLY thing that i could think if a cause would be pulling too many rpms, but gosh, if that happens every time i try to do a fast 360 or what not, i'm not gonna attempt to fly this heli again. This last crash already ruined like $400 dollars worth of equiptment since i do aerial photography (amature shooting ) and i had all my night flight equiptment on there with the carbon fiber night blades..........

(in reply to lyk2fly)
       Post #: 15