Shuddering Vibration In A 407?

[JustanAME]

you could be having cone shift up inside the mast...had this happen once..gets really rough and then if you pull in some pitch it will usually smooth out for a while...only way ot tell is to pull the head off and check the cones...vibration is VERY bad if this is happening...not just a...hey what is that...its more like...WHAT THE H%#L IS THAT...kind of shake.When it first happened to me I landed the machine...looked all over the head...could see nothing loose or broken...went flying...ship was perfectly smooth....in about 5 minutes it came back...said sorry to my passengers...took them home...flew home very slowly and got that thing on the ground...they scraped the cone set..they being the bell service rep...new set of cones...proper torque on mast nut and the NEW tool for installing the head...hasn't happened again... :shock:

 

I'll second was DGP is saying. I'm assuming you have the older mast on your 407. If your shudder appears to come and go whenever it feels like it in flight, then it's pretty much a given that the split cones aren't sitting properly around the mast. I'm afraid that this isn't a quick fix as it will involve lifting the head and repositioning it on the cones, once again assuming you don't bump them while lowering your head back down. The new mast has the "split cones" shape built in so that set-up is much better.

[JustanAME]

I'll second was DGP is saying. I'm assuming you have the older mast on your 407. If your shudder appears to come and go whenever it feels like it in flight, then it's pretty much a given that the split cones aren't sitting properly around the mast. I'm afraid that this isn't a quick fix as it will involve lifting the head and repositioning it on the cones, once again assuming you don't bump them while lowering your head back down. The new mast has the "split cones" shape built in so that set-up is much better.

 

Glad you found your snag. A servo acting up is nothing to take lightly.

 

Take care!

[DGP]

AS mentioned they have a tool for putting the head on now to keep from bumping into the cones...it screws on were the mast nut goes on and stands about 12 inches tall...as you lower the head onto the mast this tool will not allow the head to move and helps you not bump into the cones on the way down...once the head is in place you just unscrew the tool from the mast nut threads...works like a charm :up: