Harmonic Vibration

[Steve]

I've been having a few challenges with my Vibe 90 recently with canopy wobbles and nasty noises and have tracked the problems down to the start and clutch assembly where there were some mullered bearings and bearing blocks. The result is I've had to replace the whole clutch stack and the engine rear bearing as well.

Took it out for a test fly yesterday and everything seemed sweet. Sounding good and smooth as it always used to be.

A clubmate was taking a few pics and last night pointed out a problem that we'd neither spotted, nor heard. Have a look at the tail push rod. Now that's harmonic vibration if ever I saw it. I'll re-jig the push rod holder positions and try again. It's unlikely that it would have been spotted if it weren't for the photos.

[callum]

Im surprised you didnt have tail Authority control issues!

Well Spotted Though

[terryk2000]

been having similar issues with my raptor...canopy wobbles...tail wobbles..renewed the whole clutch stack and installed a quick uk third bearing..still have the issue.so will be interesting to see what you come up with
cheers
Terry

[t-rex pedro]

Got a similar problem with my 700. I'll follow this thread with interest.

[jamiem]

definately try moving the guides apart a touch. if it is harmonic, you'll change its resonance point by moving them and hopefully calm it down

[Boggy]

or maybe a blob of epoxy or solder near one of the guides as a damper?

[barney]

Terry something worth a checking very closely on a Raptor is the tail grip bearings if it uses the standard tail assembly. There is no thrust bearing and the 2x Radial bearings in each grip can be prone to failure. What happens is the inner outer race pull apart leaving the inner race on the hub throwing the grip/blade assembly.

Brian

[Steve]

I flew it today and moved the last rod guide (nearest the tail) in towards the canopy by 15mm. No more push rod vibes. Simple.

Started using a new fuel today (Bekra 16%) and very impressed with the results.

[terryk2000]

Terry something worth a checking very closely on a Raptor is the tail grip bearings if it uses the standard tail assembly. There is no thrust bearing and the 2x Radial bearings in each grip can be prone to failure. What happens is the inner outer race pull apart leaving the inner race on the hub throwing the grip/blade assembly.

Brian

Have a metal tail upgrade Brian..virtually everything has been renewed..shafts...bearings..tbh i dont think theres anything left to renew!..it even has made2fade stumped lol so any suggestions are more than welcome
Cheers
Terry

[barney]

Terry, metal tail as in the Quick UK Grips? or just the hub? If its just a changed hub it's still only got Radial bearings.

Probably already done this but try a new set of tail blades, preferably light weight Carbons..Errr are both blades facing the correct direction?.and is the tail running the correct direction? I managed running a tail blade trailing edge first for a session without any noticable flight differences. It just sounded a little different..LOL

Manager yes the Bekra 16 works well indeed and its kind to bearings as well.

[marktigere1]

Steve

Where do you get your Bekra from?

Only ask as my LHS is proving to be a problem for getting ProPower.

Ta

[Steve]

Steve

Where do you get your Bekra from?

Only ask as my LHS is proving to be a problem for getting ProPower.

Ta

Inwoods. They don't stock it though. Oredered a box and it was in within 2 days. Your LHS should be able to do the same.