20,000 mile service (ish)

[Mikej]

After my 425mm blade experiment (I didn't like the sound - at that head speed the whole heli sounded as if it was about to explode) I converted back to short boom and 500mm blades and 15/50/20/61 gearing to give a HS of 1,800 to 1,900 rpm. However I appeared to have developed a new noise - it was there with the 425mm blades and the higher HS but I don't think that it was there before I tried that - it was a sort of high-pitched "chirping" sound.

So I decided to check things out a bit more - took of the main shaft and stuck a spare main shaft in there (only into the top bearing) I leaned the shaft at a very slight angle to feel for lateral play / smoothness - it felt very "gritty", I took out the motor and primary gear - and then stuck the shaft in the top of the OWB shaft bearing - again notchy. So I bought a new set from Model Fixings here in the UK - the 8mm bearings are £1.94 each and I also bought new tail belt shaft bearings (although they turned out to be perfect) for £1.30. Just over £10 ($14) for all 6 and less than a pound postage - bargain. It all feels sooooooo much smoother now - just need to check that the noises have gone when it stops raining.

Mike.

[mjdee14]

Mike...

I'll be interested in seeing if your noise went away.....I replaced OWB and main shaft bearings for notchyness....and I still have the chirp......you can hear it in Charlies video of him flying in his back yard...

what motor are you using?

Mike D

[Mikej]

Mike,

Did you replace the OWB shaft bearings - my top one was pretty notchy. When I heard Charles' video it didn't sound the same.

I'll let you know if it goes away.

Cheers,
Mike.

[bobbybe]

yeah that one above the owb was the culprit of my chirp/squeal too

[Mikej]

Job done !!!!! I'm not sure which was the problem in my case (since I replaced 6 bearings), but she's quiet as a church mouse now - I had forgotten how nicely the 550 flies :smokin::smokin::smokin:

[jacquesjb]

Hi,
I'm interested to know what is the culprit of your chirp/squeal sound? I have a similar sound for my Hurricane also.
Thank's

[Mikej]

Jacques,

I replaced the main shaft bearings, OWB shaft bearings and tail shaft bearings (the shaft that drives the tail belt). The tail shaft bearings were perfect - did not need replacing, both of the main shaft bearings were rough and notchy (did not turn smoothly), both of the OWB shaft bearings were rough also (the top worse than the bottom). To replace the main shaft bearings and OWB shaft bearings would have cost less than £8 (€9 plus postage) and only took 2 hours in total - well worth doing just in case that is what is causing your noise. My noise sounded as if there was a small bird piloting the Hurri :)

Mike.

[jacquesjb]

Mikej,
I will try that. I have this sort of high-pitched "chirping" sound since my first fly.
After about fifty fly, the sound is always present with the same sound level.
At slow speed, she is quite quiet.
Is there a risk of damage to not change these bearing?

Jacques

[Mikej]

Jacques,

Good question - I'm not sure I'm afraid. I have about 150 flights on this Hurri (I have 2) and it only started doing it recently, so it seemed highly likely to me that is was a wear issue, which it has turned out to be.

Has yours done it from new, or did you buy second-hand ?

Good luck,

Mike

[jacquesjb]

Hi Mike

Has yours done it from new, or did you buy second-hand ?
This is a brand new helicopter, and this high-pitched "chirping" sound is not always present. Like I said i will change the bearings just to be sure.

Jacques

[bobbybe]

turns out my owb shaft bearing (top one) was completely busted in it's holder and it didn't cause my heli to crash or even fly that different... just made alot of noise till i switched it out :)

[kahn10]

although it can also create a lot of heat which can cause your owb to fail......

[Mikej]

Jacques,

My Hurri only started making the noise recently - I have had it from new, but it only started in the last 20 flights.

Best wishes,
Mike.

[kahn10]

mike you got a 3dx500 ?

[Mikej]

mike you got a 3dx500 ?

I did have a while back, but sold it last summer

[kahn10]

i guess that would answer the how did you think they compared question........

[Mikej]

i guess that would answer the how did you think they compared question........

It was nowhere near as forgiving to fly, not as "floaty", really needed to be flown all of the time, not just occasional inputs. Don't get me wrong - it was stable, but with the extra headspeed it was a lot more responsive as well and my skills were not up to it at the time.

Since I had the SE model everything was aluminium and when I crashed it cost about $80 including blades - much more than a Hurri crash, so I never flew it

Mike.