General Vibration

[treff]

Hi all. I've just done a few repairs to my heli, new feathering shaft, new tail blades and I noticed when I put the main rotor blades back and ran the heli up I had lots of vibtation, so much in fact that the helicopter was moving, dancing around the floor. I removed the blades and swopped them around. They were not upside down, I just swopped them around. Ran up again and now almost perfect, humming along like the proverbial bee. Is this normal? is it just the way I set the blades up initially i.e. one blade slightly out of track on one blade grip, perfect on the other. Cheers

 

[Tony]

Sounds like you may have had your blades just a little too tight if swapping them around fixed the issue. to me, it sounds like one was not quite in line and just couldn't be forced out. Glad you got it fixed though.

 

[coolgabsi]

One : were the blades before too tight?

Two: have you balanced the blades cog abd weight using tony's blade balancing method..

Three: do vibrations show up without blades on there abd spoiling up

Let us know

And no that is not normal .. Blades balanced , should be "Identical"

Fly safe!! have fun!

 

[treff]

Hi Tony and coolgabsi thanks for the replies and suggestions. No, I did not balanced the main blades but I did weight them to nearest gram. I did notice vibration without the blades attached. The head slide was very loose, lots of play so the head could rock back and forth. I tighten up the jesus bolt very tight and that seems to have taken most of the play out but I do not think this is bet practice. HK product I'm afraid. What is Tony's balancing method, I must have missed that. Thanks both.

 

[DAL2855]

Here's a link to tony's blade balancing blades:

 

[treff]

Thanks DAL2855 for the link to Tony's blade balancing. Very interesting indeed. Well I have run the heli up without the main blades and found that the canopy fouls the main gear. That's number one. I removed canopy and still getting vibration from somewhere. Number two is that the main gear or the gear to drive tail belt making strange noise at certain speeds so I need to investigate that. I will stripe the head down and rebuild to see if that makes any difference. If not I will remove the boom to see if that is causing the problem. Any other ideas would be most welcome. Cheers

 

[DAL2855]

Have you checked the main shaft to ensure that it's perfectly straight? Remove the head and spool the heli up looking down on it from above and ensure that the main shaft isn't the culprit! slowly spooling up watching straight down on the top of the main shaft will tell if it's straight or not.

 

[treff]

Thanks for that Dal2855 will give that a go. Cheers.

- - - Updated - - -

Just run up the heli without head and shaft is okay. No wobbles. What I have found is that the motor a Turnigy Helidrive sounds like a bag of nails. It's only done very light work for a very short amount of time. I will be really annoyed if that is the cause of the problem. Cheers

 

[Westy]

could well be.... but you can change a set of bearings for less than $10 bucks.... unless one of the magnets has dis lodged ..... then that is trash can material

 

[DAL2855]

Ok so have you torn the head down completely and then once it's back together, check the blade grips for looseness and back and forth play. Ensuring that the dampners are good.

 

[Lee]

Treff, if i was anywhere near you, i'd get that bird in perfect flying condition, and get you in the air toute suite