RunRyder RC
 2  Topic Subscribe
WATCH
 2 pages [ <<    <     1     ( 2 )    >    >> ] 1125 views POST REPLY
Scorpion Power Scorpion Power
HelicopterThunder TigerRAPTOR 90 › A shaking of the pitch slider that I can't diagnose
09-17-2007 01:29 AM  10 years agoPost 21
Dino Spadaccini

rrElite Veteran

USA

My Posts: All  Forum  Topic

dampeners

did you lube the stock ones if not due so with a good grease

RIP Roman JR
Capt USA Align Factory Team Align - Conquer Your heart
Team Futaba

PM  EMAIL  GALLERY  Attn:RR
09-17-2007 02:45 AM  10 years agoPost 22
RCHelicopterGuy

rrVeteran

Michigan

My Posts: All  Forum  Topic

That was one of the first things that Colin and Stephen Bell recommended. I grease the snot out of them.

I've been playing with the tail end this afternoon. I repositioned both bearing carriers (back one's about half way between the fin clamp and the tail box, front one about 6 inches from the front of the boom), optimized my tail transmission gear mesh, and made sure my engine alignment was as good as it could be.

I took both main and tail blades off and ran it up slowly on the ground while holding the tail gearbox. Felt smooth for as much throttle as I felt comfortable giving it. I then put the tail blades on (no main blades) and did the same thing. Still felt smooth. Then, I put the mains on and test hopped it. It's as smooth as I've ever had it, but not perfect yet. Tail vibe is about 1/4 to 1/2" up and down in both Normal and Idle-Up.

It's like I keep hitting around the problem, but I can't put my finger on it yet.

PM  EMAIL  GALLERY  Attn:RR
09-17-2007 01:16 PM  10 years agoPost 23
Dino Spadaccini

rrElite Veteran

USA

My Posts: All  Forum  Topic

insane

well i have had this problem too, i would look at the head and how is fits to the main mast is there any play if so try this just snug up the jesus bolt and then tighten up the phasing ring also maybe the main mast is a little under size causing the head to rock when you spool up then making the tail jump look at that

RIP Roman JR
Capt USA Align Factory Team Align - Conquer Your heart
Team Futaba

PM  EMAIL  GALLERY  Attn:RR
09-18-2007 12:26 AM  10 years agoPost 24
RCHelicopterGuy

rrVeteran

Michigan

My Posts: All  Forum  Topic

Well, it's a small thing and possibly a longshot, but I think I might be on to something.

I started thinking that maybe my blades or paddles were not balanced. On a lark, I put the blades on the beam (Radix 710's, don't know the weight) and they seemed to balance each other. BUT, when I marked the spanwise CG of each blade, one blade was just under 1mm off from the other. I don't know if that's enough to cause a problem, but anyway...

On the suggestion of a friend, I took a strip of electrical tape about 4 or 5 inches long (long enough to almost wrap around the blade), and I put it on the CG of one blade. Fired it up and lifted of... still kinda "busy" looking. Took the tape off and put it on the CG of the other blade... it got better. Moved it an inch or so to the inside of the CG of that blade, and I could just about swear that the vibes went away.

Maybe my eyes aren't as good as they used to be, and I'm just imagining things. Maybe I'll go out and try it again tomorrow, but if I didn't know any better, I'd think that the mismatched spanwise CG's of my blades (if I did in fact balance them correctly) may be causing me problems. Too bad I don't have another set of known good blades to check it against. Maybe I ought to do the same with my paddles as well.

PM  EMAIL  GALLERY  Attn:RR
09-18-2007 03:14 AM  10 years agoPost 25
S Bell

rrApprentice

Nova Scotia Canada

My Posts: All  Forum  Topic

Hi Shawn,

If the blades balance on a teeter balance to each other then they should not shake the machine in the hover. If your teeter balance is out that would explain the problem. Best way to verify a teeter balance is to swap blades on the tool, if the result is different and the tool no longer holds level (not showing a balanced condition as earlier) then you have your answer.

You can have blades mismatched quite a bit on the span wise c of g having different weights that indicate in balance on a serviceable teeter balance tool, these will still appear smooth in the hover. What counts is that the moments (mass times arm or mass times spanwise c of g )are the same.

To test the theory you can reduce the corrective tape and stick it on the blade tip for the same result. Figure the distance from the mast multiplied by the tape weight. Then figure the distance to the blade tip from the mast multiplied by X to give the same moment.(solve for X and that's the new tape weight)

On some foam core blades I've had to correct (to avoid unsightly tape)I drill a small hole about 4 inches from tip end of the blade inline with the blade bolt into a depth of the inside top blade skin. I then mix the correct amount of lead and epoxy into the hole and trowl smooth then use a magic marker or black/white paint to hide the fix. This is the method for correction that blade factories use, the key for technical-hair splitting perfection is to have the same blade total weight and same spanwise c of g.

Stephen

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR
09-21-2007 02:01 AM  10 years agoPost 26
coptered

rrNovice

Harvest, Alabama

My Posts: All  Forum  Topic

I have been having the same problem and today I replaced the main shaft and fixed the up and down tail shake. Take out your main shaft and roll it on a flat surface. If you see any wobble or any area raise from the surface at all replace the main shaft.

PM  EMAIL  GALLERY  Attn:RR
WATCH
 2 pages [ <<    <     1     ( 2 )    >    >> ] 1125 views POST REPLY
Scorpion Power Scorpion Power
HelicopterThunder TigerRAPTOR 90 › A shaking of the pitch slider that I can't diagnose
 Print TOPIC  Make Suggestion 

 2  Topic Subscribe

Sunday, September 24 - 4:04 am - Copyright © 2000-2017 RunRyder   EMAILEnable Cookies

Login Here
 New Subscriptions 
 Buddies Online