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Thunder Tiger 60/70/90 Raptor 60/70/90 Helicopters |
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06-11-2009, 08:15 PM | #1 (permalink) |
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Join Date: Sep 2006
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Raptor 90, bad vibration - Thoughts????
So here is the deal. Raptor 90 w/ Kasama head. For the past year or so, I have had this nasty vertical tail vibration. Looks very similar to what my R50 did way back when one of the tail blades would shoot off.
So far I have checked and/or replaced the following items. Tail Shaft Tail Blades - Currently Radix 105's Tail blade grips Tail Hub Tail Drive gears Torque tube - both ends Main Shaft Spindle Flybar Paddles Main blades Grips Dampeners Whatever is causing the issue, sometimes it is worse than others. And with as slow as the vibe is, comparitively, I am leaning towards something in the head that is causing it. Odd thing is that the vibration almost goes away while inverted. I have tried the dampeners unlubed (manufacturer recommended) and lubed. I have replaced the main shaft, flybar and spindle, tail shaft, tail hub and tail blades. And to make things worse, it only seems to get worse everytime I fly. Last time I was out, I could have sworn the thing was going to fall apart. That was until I switched to 1800 on the head. Smoooootttttthhhhhhhhh as silk the entire flight. Only problem with that is, while trying to show/explain to some buddies earlier, I was switching between 1900 and 1800 and it wasn't making any difference. The only thing that does seem consistent is tracking. At times the tracking is about 1/4" apart, and that is when the tail is perfectly smooth. Then when the tracking is perfect, the tail is shaking up and down a 1/4" or more. Mind you this all happens during the same flight. I personally would say the spindle is bent. But I have changed it out 3 different times. And always get the same result. Thoughts, comments, suggestions??? Any fresh idea's would be helpful. |
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06-11-2009, 08:40 PM | #2 (permalink) |
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Did you check the Torque tube bearings. I had one that was new and the dust cover was hiding the fact the bearing was bad.With the higher head speeds no shake or wobble at idle up she would shake. When I found the bad bearing and replaced it I was golden. Just an idea???
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06-11-2009, 08:56 PM | #3 (permalink) |
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Nem3
If you have time tomorrow I can take a look at it with you. We should probably balance your tail. I'll bring my balancer. I may be at Palos or Busse tomorrow afternoon. PM me if you are interested. Also, join our forum. https://www.helifreak.com/forumdisplay.php?f=203 |
06-11-2009, 09:13 PM | #4 (permalink) |
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Thread Starter
Join Date: Sep 2006
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I'll be at Palos for sure tomorrow.
I have checked all aspects of the tail. And am about to throw it on the balancer. That is after I dial indicate the tail shaft. Just checked the main shaft. Off 0.001" But your help in any way is more than welcome. Interesting thing I just noticed. My flybar control arms have some droop in them. NOT supposed to. So I tried moving them......... I can go from flat to about 5 degrees total droop with quite a bit of effort. Hmmmmm....... more to come.... |
06-11-2009, 09:15 PM | #5 (permalink) | |
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Quote:
What time would you be at Palos? |
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06-11-2009, 09:24 PM | #6 (permalink) |
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Thread Starter
Join Date: Sep 2006
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Start shaft has a bit of an issue. A very unhelpful set screw.... Alignment is perfect, start shaft is very very free. I always set my motor alignment by spinning the start shaft.
Only problem is something seems fishy with the top bearing, and I would like to take a look at it. But..... can't get the set screw out. If I have time, I am going to take out the whole clutch stack and get it out manually. Should be no later than 6:30, hope to be there by 6:00. But can be earlier if it helps you out. Edit to previous post - Remembered I did add a bit of droop to the flybar control arms to keep them from hitting the bottom of the blade grips. Just tightened the set screws about 1/2 turn without going ape crazy on them. Worried that the flybar may be all gouged up in that area. We'll see. |
06-11-2009, 09:48 PM | #7 (permalink) | |
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Quote:
I'll PM you my cell. |
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06-11-2009, 10:01 PM | #8 (permalink) |
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Thread Starter
Join Date: Sep 2006
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Tail shaft is off 0.0015"
After Fixing the flybar control arm droop issue. I checked tracking. Was off about a degree and a half. Could be the issue, but I don't think so. With the much tighter and stiffer Kasama a degree and half of bad tracking could be the cause. I'll have to see tomorrow. |
06-15-2009, 09:13 PM | #9 (permalink) |
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Join Date: Aug 2008
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did you track down your problem yet? I am having the same problem, checked all the same stuff (shafts, ect.) I am thinking it is in the head, as once I get to a certain speed, it goes away completely, but comes back when spooling down....once in a while when I load the head up pretty good it will appear midfligt, but goes away once the headspeed picks back up.
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06-15-2009, 09:15 PM | #10 (permalink) |
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Not sure what it was exactly, but he fixed it.
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06-15-2009, 09:44 PM | #11 (permalink) |
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Thread Starter
Join Date: Sep 2006
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I suspect it was a combination of the flybar control arms being loose and the tracking being off. Once I fixed both of those things, the harsh vibration disappeared. Flying it friday evening with my buddies at Palos revealed one final vibration. Not so harsh, but noisy and annoying. The only problem I had left is that I could move start shaft side to side. Like the bearing was toast. Reason I hadn't taken it apart the night before is because I was not able to get one of the set screws out. Anyways, I took the hole clutch stack out. Found out that the top bearing must have spun and it ground a groove into the start shaft 8 thousandths deep. This was causing the start shaft to move side to side and cause the vibration. Went to the LHS Saturday, got new start shaft, clutch bell, main shaft and tail drive bearings. Replaced every bearing in the main frames. Just for good measure.
Flew Sunday morning. Fricken fantastic. Peeeeerrrrrrfectly smooth. Not a single vibration. Unfortunately, I have come across another problem. Flying Sunday, first flight, 3/4 of the way through the flight my engine/servo/govenor????? starting surging very badly. It felt like it was going from idle to full throttle. I never got a chance to figure out it if was my carbsmart, GV-1, throttle servo or needle settings that was causing it. Landed and knicked the tail blades on a rock or something. Took out the blades and tail drive gears. Should have them in a few days, so I can get out and figure out what the problem is before the Winimac funfly this Saturday. Hope some of this helps. |
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