Pulsing sound from 600LE

[vartegrich]

There is spotting on the crank as can be seen on the photo, but it isn't rough to the touch, presuming that if it were rust you would be able to feel a slight roughness.

I flew it today and the pulsing didn't seem as prominent, but the heli just doesn't sound right. It has a roughness to it, difficult to explain really but it is noticeable even to those not familiar with helis.

[Nick B]

My guess is it will get worse.I spoke to my mate today who had a tail twitch develope along with a rough sounding top end,there was no death rattle but when we stripped it down the bearing was shot,not broke but very rumbly when span on the finger close to the ear...the heli now runs/flies like new

If os50/55 then get yourself a new bearing

SKF 61902 Open Deep Groove Ball Bearing 15x28x7mm Simply Bearings Ltd ~ Oil Seals SKF FAG TIMKEN KOYO NTN NKE TRULOC Needle Rollers Taper Rollers Rod Ends Oilite Bushes Loose Balls O Rings Grease Plain Thrust

[vartegrich]

I shall get one ordered and see how things improve. I see your link is for a non-OS bearing. Are these a better option?

[Nick B]

These are what OS use in the 55 now,the original 50 bearing is plastic caged but is the same size

I think the death rattle is easier to hear and heard sooner reducing the chance of bearing failure,ive replaced plastic caged ones that were quieter in the DR but were rustier than the SS ones

Just out of interest,what fuel do you use?

[vartegrich]

It did the first 10 flights on 10% Prosynth but has now done 5 litres on Optifuel 20%

[Geek]

I think it's engine bearings like Nick
while you are taking the engine out
Check the exhaust for a loose baffle
I had one brake in a Align pipe

Rusty crank engine bearings

[vartegrich]

I had the engine out this morning before the flying session. The pipe seems nice and solid but the nipple was a little loose.
Rusty Crank.....ain't that some cartoon character?

[Nick B]

That nipple,have you epoxy'd it in place??

Unless you are confident with your auto-rotations id get it glued

[vartegrich]

Well I have had two unplanned autos so far. The first after popping the piston and the second after failing to get the governor set right which resulted in locking the throttle to idle whilst 20foot up in the air (scary).
Epoxying the nipple was something I had not thought of, and I don't think many others in the club have bothered either, so that is a worthwhile tip worth sharing. Thank you very much.
By the way, heli pilots are in the minority at our club so I'm leading the way in finding all the problems.

[vartegrich]

I think it's engine bearings like Nick
while you are taking the engine out
Check the exhaust for a loose baffle
I had one brake in a Align pipe

Rusty crank engine bearings

Well I pulled the engine apart and even though not showing any real signs of rust, there was a noticeable grind to the rear bearing.
New ones have now gone in and as soon as the weather breaks I shall fire it up and see if it behaves itself any better.
I did the check on the muffler and that was all intact.

Finally, a big thank you to everyone who assisted in sorting out the problem.

[Nick B]

Im sure you will enjoy your smooth and quiet engine now

[vartegrich]

Well at least for the next 6 months until it goes again.