开云体育

I have a new G11G carrying a ~50lb payload. I wasnt able to balance the payload very well (even setting the Altitude to horizontal). So I opt’d for the wavy washer upgrade. I just installed it tonight and am concerned the clutch will no longer tighten enough.

Before the wavy washer install with the RA on the bench if I fully tighten the clutch knob no matter how hard I try I cannot rotate the RA by hand.

With the wavy washer installed and the clutch knob fully tightened I am able to palm the RA extension and rotate the RA by hand. I don’t see how this could hold a 50lb payload without slipping.

Am I missing something?

Did you verify the clutch surfaces remained dry.? Free from any contamination from solids or oil from grease?

It's perhaps easier with a number.? A measure the torque that breaks the starting friction using the delta of torque from the outer counterweight slip minus balance positions.

My stock G11G currently slips at the RA around 8 foot-pounds currently.?

I have always wondered how tight the clutch knobs should be. On my 2 SkyWatcher mounts they have levers which are fairly easy to set to a consistent level.

How are you getting a torque wrench on the RA? I have the RA extension kit and don’t see any bolt- like object to put a socket onto.

?This is what the RA clutch looked like when I disassembled it to install the wavy washer.

Hi Peter,

Just noticed your posting. The wavy washer is intended to take a little downward force off the RA clutch so you can balance your load at your latitude. You can get a sense of the balance by gently pushing CW or CCW on the counterweight bar, but this is never a freewheeling balance like some other brands. After balancing, there should be enough stiction to keep your mount from sliding in RA throughout the night. The clutch pad and surrounding plates should be grease and oil free as already mentioned.

If you are still uncomfortable with the lack of resistance you can remove the wavy washer and balance RA by cranking the altitude knob as close to 0 as possible. Then there will be as little normal force as possible minimizing the friction on the clutch surfaces. Just be careful you don't tip your tripod over when in this lowered position (not to worry with a pier). You can hang some temporary weights under the tripod to help with center of mass. When balance is achieved to satisfaction, crank your altitude back up to your latitude. You will need to redo your polar alignment after doing this. This is the method I use when changing telescopes, but I have a heavy duty in ground pier to hold all in place. And I also use the Micheal Herman high friction clutch pads which have less slippage as compared to?the Losmandy stock polyethylene type. Balance does not have to be perfect and most go for an east-heavy balance in RA, and a camera end heavy balance in Dec.

Good luck,

John
--
_____________________________________________________________________________________________________________________________________________________________________________

Losmandy G11G2 on pier; refurbed Losmandy G11 with OnStep controller; SkyShed design roll-off observatory; ZWO ASI2600MM-P; ZWO ASI071MC; Sky-Watcher Esprit 100 ED with field flattener; Celestron C925 Edge HD with 0.7XFR, William Optics Zenithstar 61 APO; PHD2, Sequence Generator Pro and PixInsight user

On Sat, Mar 23, 2024 at 09:14 PM, Peter Eacmen wrote:

How are you getting a torque wrench on the RA?

I'm not suggesting a torque wrench and adapter.? Just the moment arm and force applied.? With the RA balanced and horizontal we slide the counterweights outward (same if inward).? ?We configure weights such that at some position the clutch slips.? For the weight chosen the difference in the center of mass positions calculates as (|"torque at slip" - "torque at balance"|).

Example, my 150mm refractor weighs 32# balanced/horizontal with a stack of 7# (inner) and two 11# (outer).? The outer two 11# balance at 12" (mass center).? On moving the two weights the clutch slips when moving 5" (I tensioned the clutch very tight).? The torque at 12" is 24 ft-lbs (12lbs * 2 * 12in / 12 in/ft) and there exist an equal opposing force (balanced).? The force at 17" becomes 34 ft-lbs.? Added torque to slip the clutch becomes then | 34 - 24 | or 10 ft-lbs.

{It's equivalent to saying, remove the weights at the balanced position and place them at the point of slippage or 17".? At 17" this requires 17# to balance but we place 7# more than that.? That extra 7lbs applies 7lbs * 1.4 ft or 10 ft-lbs.}

Balanced


Slipping

I have 2 Wavy Washers coming. I hope I didn't buy them for nothing. I do have quite the dead zone when balancing.?