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Balance weights on Hartzell CS prop hub

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Mauledriver(at)nc.rr.com
Guest

Posted: Tue Mar 15, 2011 3:49 pm Post subject: Balance weights on Hartzell CS prop hub

A close examination of my (unused, unmounted) Hartzell prop hub, I see 2 

screws safety wired together on the hubs, near where the prop shafts are 

mounted.  What's strange is that there are 8 threaded screw holes, 2 

pair at each prop shaft.  But only 2 of the 8 are in place and safety wired.



In the Owner's manual, they are called 'balance weights'.  In one 

drawing it looks like a plate of some sort might be mounted under the 

screws.  One other diagram 'suggests' safety wire.  Otherwise, I can 

find no reference to them.



Anyone know anything about this?



I know this isn't enough information to easily picture this but I'm 

thinking someone is familiar enough to know what I'm talking about.  

It's weird to see 8 holes and only 2 screws.



Bill Watson

pitts_pilot(at)bellsouth.
Guest

Posted: Tue Mar 15, 2011 4:04 pm Post subject: Balance weights on Hartzell CS prop hub

The screws hold balance weights, which are plates that mount under pairs 

of screws.  The two screws you see are part of the 'weight' ..... but no 

plates were needed. meaning that the initial assembly and static balance 

were almost spot on.



I once balanced a prop on a homebuilt that the owner had taken apart 

after a gear-up landing ...... his third.  He 'straightened' the bent 

blades with a 5 Lb maul (already spent too much on new blades!), 

reassembled, and when he did he put all the weights on one blade ...... 

on one side!  The prop stayed together longer than the owner.  I was amazed.

Linn



On 3/15/2011 7:44 PM, Bill Watson wrote:

 	  Quote: 	
		   



 A close examination of my (unused, unmounted) Hartzell prop hub, I see 

 2 screws safety wired together on the hubs, near where the prop shafts 

 are mounted.  What's strange is that there are 8 threaded screw holes, 

 2 pair at each prop shaft.  But only 2 of the 8 are in place and 

 safety wired.



 In the Owner's manual, they are called 'balance weights'.  In one 

 drawing it looks like a plate of some sort might be mounted under the 

 screws.  One other diagram 'suggests' safety wire.  Otherwise, I can 

 find no reference to them.



 Anyone know anything about this?



 I know this isn't enough information to easily picture this but I'm 

 thinking someone is familiar enough to know what I'm talking about.  

 It's weird to see 8 holes and only 2 screws.



 Bill Watson

Mauledriver(at)nc.rr.com
Guest

Posted: Tue Mar 15, 2011 6:27 pm Post subject: Balance weights on Hartzell CS prop hub

That's how I interpreted it, but in the beginning, didn't have a clue.



Thanks, that's what I wanted to hear.



Bill

do not archive



On 3/15/2011 7:57 PM, Linn Walters wrote:

 	  Quote: 	
		   



 The screws hold balance weights, which are plates that mount under 

 pairs of screws.  The two screws you see are part of the 'weight' 

 ..... but no plates were needed. meaning that the initial assembly and 

 static balance were almost spot on.



 I once balanced a prop on a homebuilt that the owner had taken apart 

 after a gear-up landing ...... his third.  He 'straightened' the bent 

 blades with a 5 Lb maul (already spent too much on new blades!), 

 reassembled, and when he did he put all the weights on one blade 

 ...... on one side!  The prop stayed together longer than the owner.  

 I was amazed.

 Linn



 On 3/15/2011 7:44 PM, Bill Watson wrote:

> 

>

> A close examination of my (unused, unmounted) Hartzell prop hub, I 

> see 2 screws safety wired together on the hubs, near where the prop 

> shafts are mounted.  What's strange is that there are 8 threaded 

> screw holes, 2 pair at each prop shaft.  But only 2 of the 8 are in 

> place and safety wired.

>

> In the Owner's manual, they are called 'balance weights'.  In one 

> drawing it looks like a plate of some sort might be mounted under the 

> screws.  One other diagram 'suggests' safety wire.  Otherwise, I can 

> find no reference to them.

>

> Anyone know anything about this?

>

> I know this isn't enough information to easily picture this but I'm 

> thinking someone is familiar enough to know what I'm talking about.  

> It's weird to see 8 holes and only 2 screws.

>

> Bill Watson

drfred(at)suddenlinkmail.
Guest

Posted: Wed Mar 16, 2011 6:47 am Post subject: Balance weights on Hartzell CS prop hub

Bill,



I had my prop balanced after about 150 hrs.  The weights actually went 

in the holes on the flywheel.  No more than a AN3 screw and a couple of 

washers.  You shouldn't need to do anything else with the prop itself.



Dr Fred.



On 3/15/2011 6:44 PM, Bill Watson wrote:

 	  Quote: 	
		   



 A close examination of my (unused, unmounted) Hartzell prop hub, I see 

 2 screws safety wired together on the hubs, near where the prop shafts 

 are mounted.  What's strange is that there are 8 threaded screw holes, 

 2 pair at each prop shaft.  But only 2 of the 8 are in place and 

 safety wired.



 In the Owner's manual, they are called 'balance weights'.  In one 

 drawing it looks like a plate of some sort might be mounted under the 

 screws.  One other diagram 'suggests' safety wire.  Otherwise, I can 

 find no reference to them.



 Anyone know anything about this?



 I know this isn't enough information to easily picture this but I'm 

 thinking someone is familiar enough to know what I'm talking about.  

 It's weird to see 8 holes and only 2 screws.



 Bill Watson

Mauledriver(at)nc.rr.com
Guest

Posted: Wed Mar 16, 2011 7:27 am Post subject: Balance weights on Hartzell CS prop hub

So it seems that the factory does some balancing of the new prop itself 

(per Linn).

\

Then if the prop installation is balanced by whatever means, weights may 

be applied to the engine flywheel.



Thanks Dr Fred.



On 3/16/2011 10:41 AM, Fred Williams, M.D. wrote:

 	  Quote: 	
		   

 <drfred(at)suddenlinkmail.com>



 Bill,



 I had my prop balanced after about 150 hrs.  The weights actually went 

 in the holes on the flywheel.  No more than a AN3 screw and a couple 

 of washers.  You shouldn't need to do anything else with the prop itself.



 Dr Fred.

Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Wed Mar 16, 2011 7:38 am Post subject: Balance weights on Hartzell CS prop hub

What you are discussing is the difference between static balance, which 

is done by factory or any prop shop when they service a prop which is 

simply having prop balanced end to end about the center point; and 

dynamic balance that is done on the aircraft with the engine running, 

and will be different for every engine, for any difference in prop 

clocking if it is changeable. A prop must have proper static balance 

before you will be able to effectively do a dynamic balance.

On 3/16/2011 8:23 AM, Bill Watson wrote:

 	  Quote: 	
		   



 So it seems that the factory does some balancing of the new prop 

 itself (per Linn).

 \

 Then if the prop installation is balanced by whatever means, weights 

 may be applied to the engine flywheel.



 Thanks Dr Fred.



 On 3/16/2011 10:41 AM, Fred Williams, M.D. wrote:

> 

> <drfred(at)suddenlinkmail.com>

>

> Bill,

>

> I had my prop balanced after about 150 hrs.  The weights actually 

> went in the holes on the flywheel.  No more than a AN3 screw and a 

> couple of washers.  You shouldn't need to do anything else with the 

> prop itself.

>

> Dr Fred.

>

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

jesse(at)saintaviation.co
Guest

Posted: Wed Mar 16, 2011 7:45 am Post subject: Balance weights on Hartzell CS prop hub

As was mentioned, the manufacturer (and/or prop shop) will do a balance on the prop before delivery, but the weights added to the ring gear are for a dynamic balance, which balances the prop as mounted with the spinner and all of that stuff on it.

do not archive

Jesse Saint

Saint Aviation, Inc.

jesse(at)saintaviation.com

C: 352-427-0285

F: 815-377-3694

On Mar 16, 2011, at 10:41 AM, Fred Williams, M.D. wrote:

 	  Quote: 	

 Bill,

 I had my prop balanced after about 150 hrs.  The weights actually went in the holes on the flywheel.  No more than a AN3 screw and a couple of washers.  You shouldn't need to do anything else with the prop itself.

 Dr Fred.

 On 3/15/2011 6:44 PM, Bill Watson wrote:

> 

> 

> A close examination of my (unused, unmounted) Hartzell prop hub, I see 2 screws safety wired together on the hubs, near where the prop shafts are mounted.  What's strange is that there are 8 threaded screw holes, 2 pair at each prop shaft.  But only 2 of the 8 are in place and safety wired.

> 

> In the Owner's manual, they are called 'balance weights'.  In one drawing it looks like a plate of some sort might be mounted under the screws.  One other diagram 'suggests' safety wire.  Otherwise, I can find no reference to them.

> 

> Anyone know anything about this?

> 

> I know this isn't enough information to easily picture this but I'm thinking someone is familiar enough to know what I'm talking about.  It's weird to see 8 holes and only 2 screws.

> 

> Bill Watson

> 

> 

> 

> 

> 

>

Neal.George(at)hurlburt.a
Guest

Posted: Wed Mar 16, 2011 9:09 am Post subject: Balance weights on Hartzell CS prop hub

True as far as it goes.



Not every engine that this prop will fit is equipped with a flywheel in

which to mount balance weights, and not everybody thinks the spinner

back-plate is the best place to be poking holes for balance bolts.



Neal



--

jjessen01

Joined: 27 Sep 2010
Posts: 50

Posted: Wed Mar 16, 2011 10:03 am Post subject: Balance weights on Hartzell CS prop hub

Does doing a static balance apply to all props, including wood?  



John J

pitts_pilot(at)bellsouth.
Guest

Posted: Wed Mar 16, 2011 11:01 am Post subject: Balance weights on Hartzell CS prop hub

Putting balance weights on the flywheel will refine the balance done 

with the prop weights, which is a static balance.  I recommend everyone 

get their prop balanced to reduce vibration which lessens wear/tear on 

airframes and pilots alike.  Put a clear glass of water on the 

glareshield and see how big the ripples get.  Do it again after the 

balance job.  See the results.  Engine/prop vibrations are very 

subjective when taken through the seat of your pants.

Linn

On 3/16/2011 10:41 AM, Fred Williams, M.D. wrote:

 	  Quote: 	

 <drfred(at)suddenlinkmail.com>

 Bill,

 I had my prop balanced after about 150 hrs.  The weights actually went 

 in the holes on the flywheel.  No more than a AN3 screw and a couple 

 of washers.  You shouldn't need to do anything else with the prop itself.

 Dr Fred.

 On 3/15/2011 6:44 PM, Bill Watson wrote:

> 

>

> A close examination of my (unused, unmounted) Hartzell prop hub, I 

> see 2 screws safety wired together on the hubs, near where the prop 

> shafts are mounted.  What's strange is that there are 8 threaded 

> screw holes, 2 pair at each prop shaft.  But only 2 of the 8 are in 

> place and safety wired.

>

> In the Owner's manual, they are called 'balance weights'.  In one 

> drawing it looks like a plate of some sort might be mounted under the 

> screws.  One other diagram 'suggests' safety wire.  Otherwise, I can 

> find no reference to them.

>

> Anyone know anything about this?

>

> I know this isn't enough information to easily picture this but I'm 

> thinking someone is familiar enough to know what I'm talking about.  

> It's weird to see 8 holes and only 2 screws.

>

> Bill Watson

pitts_pilot(at)bellsouth.
Guest

Posted: Wed Mar 16, 2011 11:16 am Post subject: Balance weights on Hartzell CS prop hub

My experience says it's harder to get a good balance with a wooden prop 

because it flexes more than a metal one.  It can be done, just takes 

longer, and you really need to know what RPM you cruise at most often as 

RPM will make a difference.  There are lots of other 'things' that make 

a dynamic balance job harder too.

Linn



On 3/16/2011 2:00 PM, John J wrote:

 	  Quote: 	
		   



 Does doing a static balance apply to all props, including wood?



 John J

acsjohn

Joined: 27 Jul 2009
Posts: 15
Location: Australia

Posted: Fri Mar 18, 2011 2:35 pm Post subject: Balance weights on Hartzell CS prop hub

Hi Bill, indeed they are balance weights and depending upon the static balance horizontally and/or vertically are applied to the various screw locations to affect horizontal or vertical balance in various numbers. If you don't have many, you most likely have a well balanced prop statically. Dynamically is a different thing and a good thing to do when early in your flying phase. Balance weights will then be added most likely to the spinner backplate in addition. Also make sure the lockwire running between the screws isn't capable of sawing a groove in the blade as it moves during constant speeding.  John 40315

VH-XIO 50hrs



On Wed, Mar 16, 2011 at 9:44 AM, Bill Watson <Mauledriver(at)nc.rr.com (Mauledriver(at)nc.rr.com)> wrote:

 	  Quote: 	
		   --> RV10-List message posted by: Bill Watson <Mauledriver(at)nc.rr.com (Mauledriver(at)nc.rr.com)>

 

 A close examination of my (unused, unmounted) Hartzell prop hub, I see 2 screws safety wired together on the hubs, near where the prop shafts are mounted.  What's strange is that there are 8 threaded screw holes, 2 pair at each prop shaft.  But only 2 of the 8 are in place and safety wired.

  

 In the Owner's manual, they are called 'balance weights'.  In one drawing it looks like a plate of some sort might be mounted under the screws.  One other diagram 'suggests' safety wire.  Otherwise, I can find no reference to them.

  

 Anyone know anything about this?

 

 I know this isn't enough information to easily picture this but I'm thinking someone is familiar enough to know what I'm talking about.  It's weird to see 8 holes and only 2 screws.

 

 Bill Watson

 

 

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-- 



ACS Propeller

 John Dunne

Managing Director

www.acspropeller.com.au

Aviation Component Services (Qld) Pty Ltd.

T/A "ACS Propeller"

 Archerfield Airport, Queensland Australia

PH: 61 7 3274 4500 FAX: 61 7 3274 4010



 



 

  [quote][b]

acsjohn

Joined: 27 Jul 2009
Posts: 15
Location: Australia

Posted: Fri Mar 18, 2011 3:25 pm Post subject: Balance weights on Hartzell CS prop hub

Apologies to Bill and the list for rudely leaving my calling card on my post!John 40315 VH-XIO

[quote] 

On Wed, Mar 16, 2011 at 9:44 AM, Bill Watson <Mauledriver(at)nc.rr.com (Mauledriver(at)nc.rr.com)> wrote:

  	  Quote: 	
		   --> RV10-List message posted by: Bill Watson <Mauledriver(at)nc.rr.com (Mauledriver(at)nc.rr.com)>

 

 A close examination of my (unused, unmounted) Hartzell prop hub, I see 2 screws safety wired together on the hubs, near where the prop shafts are mounted.  What's strange is that there are 8 threaded screw holes, 2 pair at each prop shaft.  But only 2 of the 8 are in place and safety wired.

   

 In the Owner's manual, they are called 'balance weights'.  In one drawing it looks like a plate of some sort might be mounted under the screws.  One other diagram 'suggests' safety wire.  Otherwise, I can find no reference to them.

   

 Anyone know anything about this?

 

 I know this isn't enough information to easily picture this but I'm thinking someone is familiar enough to know what I'm talking about.  It's weird to see 8 holes and only 2 screws.

 

 Bill Watson

	




 



 

 [b]

Mauledriver(at)nc.rr.com
Guest

Posted: Fri Mar 18, 2011 3:36 pm Post subject: Balance weights on Hartzell CS prop hub

On 3/18/2011 6:31 PM, John Dunne wrote:

 	  Quote: 	
		   Hi Bill, indeed they are balance weights and depending upon the static 

 balance horizontally and/or vertically are applied to the various 

 screw locations to affect horizontal or vertical balance in various 

 numbers. If you don't have many, you most likely have a well balanced 

 prop statically. Dynamically is a different thing and a good thing to 

 do when early in your flying phase. Balance weights will then be added 

 most likely to the spinner backplate in addition. Also make sure the 

 lockwire running between the screws isn't capable of sawing a groove 

 in the blade as it moves during constant speeding.

 John 40315

 VH-XIO 50hrs

Thanks for the tip about the lockwire... will have to take a look.
	




Bill

do not archive

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