Head shake

[vinnyd]

Originally Posted by Ah Clem

Danny,

"not sure how lubed dampers would solve anything."

The spindle move inside of the dampers, and the dampers move inside of the head pocket. The don't move a long distance, but they do it very rapidly.

If they stick, they wear out faster (bear in mind, that at 2200 RPM, the spindle is flapping one full cycle, 2200 times per minute).

Lubing them is an old trick to make the last longer and eliminate one source of vibration.

Mine have lasted a lot longer with lubrication.

Soap helps you get them installed, but does not provide long lasting lubrication.

Is this a rotational movement about the axis of the feathering shaft or linear movement along its axis?


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[dannylightning]

Originally Posted by Ah Clem

Danny,

"not sure how lubed dampers would solve anything."

The spindle move inside of the dampers, and the dampers move inside of the head pocket. The don't move a long distance, but they do it very rapidly.

If they stick, they wear out faster (bear in mind, that at 2200 RPM, the spindle is flapping one full cycle, 2200 times per minute).

Lubing them is an old trick to make the last longer and eliminate one source of vibration.

Mine have lasted a lot longer with lubrication.

Soap helps you get them installed, but does not provide long lasting lubrication.

i know the soap dries up and the dampers are not lubed. it just gets them on and off.

i guess my theory was that the blade grips rotate on the shaft, the shaft does not need to spin. i know the shaft moves tilts in flight and the dampers flex with the shaft but i guess i never really thought about it. i see how that could put some extra wear on the dampers.

what kind of lube do you use. since allot of lube can eat the kbdd's i quit using lube. i treid synthetic tri flow greese but that stuff dries up and turns into a sticky paste. it did not seem to work out well for me.

one more question. why don't you use the quote button. lol

[Magnazan]

I've used White Lithium grease and Dry PTFE (Teflon). Both work well.

[GimpyGolden]

Originally Posted by dannylightning

one more question. why don't you use the quote button. lol

+1, not pickin on ya RAK.

[dannylightning]

Originally Posted by GimpyGolden

+1, not pickin on ya RAK.

i am picking on him but also wondering why not at the same time. so its a win win situation.

i think i know him well enough to give him a hard time.

it makes things easier to determine who i s saying what when you use the quote button.


what about silicon spray ?? would that work ok for dampers..

[Primal]

Silicon spray should be fine as long as it's 100% silicone. Some of the other silicone sprays have ethane and ketones mixed in which will most likely attack the damper material

[OverTemp]

Originally Posted by vinnyd

Is this a rotational movement about the axis of the feathering shaft or linear movement along its axis?


Sent from my iPhone using Tapatalk

Neither. It's the shaft rocking/flapping up/down with the blades.

[Ah Clem]

I use silicon grease of the type used for brake parts-it does not attach plastic or rubber.

"Is this a rotational movement about the axis of the feathering shaft or linear movement along its axis?"

Neither, it is flapping motion (one side of the spindle moves up while the other moves down.


"i am picking on him but also wondering why not at the same time. so its a win win situation.

i think i know him well enough to give him a hard time.

it makes things easier to determine who i s saying what when you use the quote button."


It's ok, I am in tears (actually, I am in Alhambra, but no one is paying any attention to that).


As far at the quotes button goes, I just never bothered with it.

"Quotes, un-quotes, and quotes-add another quote and make it a gallon...:
(Groucho Marx)

[dannylightning]

Originally Posted by Ah Clem

I am in Alhambra, but no one is paying any attention to that

?????

[Ah Clem]

Danny,

I was teasing about your statement about giving me a hard time (which you do know me well enough to to).

I said I was "in tears, actually, I am in Alhambra" (I live in Alhambra, but don't hold that against me).

[dannylightning]

Originally Posted by Ah Clem

Danny,

I was teasing about your statement about giving me a hard time (which you do know me well enough to to).

I said I was "in tears, actually, I am in Alhambra" (I live in Alhambra, but don't hold that against me).

lol, is it that bad there ??

[Primal]

Originally Posted by Primal

Anyone running the blue dampers at 2100 or so headspeed?

Well, the last week or so I've been trying to get the kbdd green dampers to break in. No go. Still shakes in the 1850 to 2000 range.

Finally got fed up and replaced the green with kbdd blue dampers. Problem solved. Super smooth in the same headspeed range.

Going to try multiple headspeeds to make sure they're ok, but to get above 2000 I am going to need a new motor. The compass one is much too low KV.

[TheBum]

Originally Posted by Primal

Going to try multiple headspeeds to make sure they're ok, but to get above 2000 I am going to need a new motor. The compass one is much too low KV.

Instead of getting a new motor, try a 14T pinion first.

[GimpyGolden]

He's been running a 15 tooth Synergy.
P, what throttle % are you running in the Kos?

[Primal]

Originally Posted by GimpyGolden

He's been running a 15 tooth Synergy.
P, what throttle % are you running in the Kos?

Already running the 15 tooth as Gimpy mentioned.

Throttle is at 80 in the kos. Headspeed at 2000. I tried higher throttle number but run out of headroom on the governor.

Math works out to 430kv motor.

[Rob43]

Wanted to offer up some recent product info I've learned through testing on the 6HVU concerning dampers...

Last summer, I consulted an engineer at Dow Corning, Molykote Division to get a recommendation on a suitable lubricant for the plastic gears we use in our helis. After some investigating into our application details (materials meshing, temp, speeds, loads, etc.) he came back with this:

http://www.amazon.com/Dow-Corning-Mo...me+cold+grease

It was no surprise that it works very well on the gears.

However...I had a wobble on spool-up and spool-down as the rotor passed through a certain speed. I had already lubed with Triflow as I always have. However, it's not easy to get the product in place since there is so much compressive stress squeezing it out of place. I decided to dismantle the head and relube with the Triflow. I just couldn't "shake" the brief wobble. Since I had in mind some test flying using a 7 cell pack, I needed this head to smooth-out at what turned out to be the speed at which my wobble occurred. I decide to take the head apart again, and relube using the Molykote. The results were immediate. The spindle centered on the first spool up, and from that point on, the head was smooth as butter at all speeds. Several flights...it remained much smoother on spool-up, at the low speeds I was flying, where stiff dampers might otherwise cause wobbles, and when I spooled down...every time since I applied it. The Molykote product is considerably less tacky than Triflow. I could tell when I assembled the head and dampers that this was going to be more effective for this application. The extremely high compressive stress of the dampers when the spindle is inserted simply wasn't allowing the Triflow to flow at all. The Molykote seems to be much better suited, and since it's a synthetic silicone based lubricant, should be compatible with the damper material as well.

It's not cheap to buy..since the tube I bought was about $25, but it should last a very long time. I could pretty easily send you a sample to try so you don't have to buy the tube. Send me a PM if you're interested.

[TheBum]

Sounds like it might be good for thrust bearings too. I find Triflow tends to clump with very little ball contact.

[Ah Clem]

Rob43,

Great information, sir!

I don't think $25 is a lot for a tube of silicone grease.

I finally finished the tube that my father and I used to use when overhauling brakes on our cars (the tube was from the 1970's). Did lots of brakes and quite a few helicopters with that tube of grease!

That tube you purchased will probably do several decades worth of helicopters dampers!

[dannylightning]

yeah 20 some bucks for a big tube and it will last you for a long time so i dont see that as expensive either.. i still have a tube of grease from the early 90's

5.3 oz i am not quite sure how big the tube is. i may order some though..

[Primal]

I'll try it. Can't hurt