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Prop balancing

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Bill Strahan

Joined: 20 Aug 2008
Posts: 145

Posted: Wed Nov 11, 2009 12:50 am Post subject: Prop balancing

I fabricated the brackets to mount my dyna-vibe prop balancing sensors to the Jabiru yesterday.  I got everything mounted just as I was running out of time, so I only ran the engine briefly to measure vibration at 2000 rpm.  I haven't actually gotten to do the balancing part yet.



But the reading was pretty shocking.  I was showing .38 IPS at 2000 RPM.  That's pretty high.  The plane feels very smooth though!



The sensors are mounted directly to the engine so I'm guessing that the smoothness is due in large part to a very effective engine mount and perhaps some natural dampening of the composite fuselage.



My Grumman felt positively buzzy at .26 IPS and felt MUCH less smooth than my Lightning does even though my Lightning is showing a higher vibration level at the engine itself.  Once I got the Grumman to .05 IPS it was silky smooth.



So, I'm thinking that when I get the Jabiru down in that range coupled with the obviously better engine vibration isolation in the mount/fuselage of my Lightning that I'll only be able to tell the engine is running by the noise or looking at the EFIS.  



I'll post my results after I actually balance it and test fly it tomorrow.



Bill

mark(at)flylightning.net
Guest

Posted: Wed Nov 11, 2009 5:35 am Post subject: Prop balancing

It's amazing what you can accomplish when you actually take your plane

home!!  



Anybody interested in a nice yellow Grumman?



All in fun.



Mark



--

8wn(at)comcast.net
Guest

Posted: Wed Nov 11, 2009 5:37 am Post subject: Prop balancing

Bill



Looks like you will have no problem bringing the ips below .07. I have been 

balancing props for a while and would like to have more info from you.

What type of prop? Ground adjustable or fixed?

What type of spinner. Composite or metal?

What engine, solid or hydraulic.

Hours on engine?



I have found much worse  on a Lighting I am working with. Static RPM was 

2675.

First run was 3.5 ips. That is twice as high as any I have ever seen and way 

over the maximum. Prop was pulled, ground adjustable, sent to factory for 

rework and returned.  Next run was about 2.8. Composite spinner was removed 

and vibe was .8+-. Balanced to about .35.  New metal spinner was installed 

and will run a new balance soon.  Engine is solid lifters at about 250 

hours.  I will be doing a balance on my Lightning in the next week.



Hope more will start having their aircraft dynamic balanced. It is worth the 

cost.

Johnny Thompson

---

dashvii(at)hotmail.com
Guest

Posted: Wed Nov 11, 2009 6:37 am Post subject: Prop balancing

Bill C  I too am very interested in your prop balancing.  Perhaps you can write a little something for the newsletter as I believe this would help everybody enjoy their aircraft more and over 1000+ hours is bound to help your engine life and reliability.  Thanks C Brian W.

[quote] Subject: Prop balancing

 From: bill(at)gdsx.com

 Date: Wed C 11 Nov 2009 00:50:52 -0800

 To: lightning-list(at)matronics.com

 I fabricated the brackets to mount my dyna-vibe prop balancing sensors to the Jabiru yesterday.  I got everything mounted just as I was running out of time C so I only ran the engine briefly to measure vibration at 2000 rpm.  I haven't actually gotten to do the balancing part yet.

 But the reading was pretty shocking.  I was showing .38 IPS at 2000 RPM.  That's pretty high.  The plane feels very smooth though!

 The sensors are mounted directly to the engine so I'm guessing that the smoothness is due in large part to a very effective engine mount and perhaps some natural dampening of the composite fuselage.

 My Grumman felt positively buzzy at .26 IPS and felt MUCH less smooth than my Lightning does even though my Lightning is showing a higher vibration level at the engine itself.  Once I got the Grumman to .05 IPS it was silky smooth.

 So C I'm thinking that when I get the Jabiru down in that range coupled with the obviously better engine vibration isolation in the mount/fuselage of my Lightning that I'll only be able to tell the engine is running by the noise or looking at the EFIS.  

 I'll post my results after I actually balance it and test fly it tomorrow

catalpaaviation(at)wideba
Guest

Posted: Wed Nov 11, 2009 2:23 pm Post subject: Prop balancing

Hullo all,  

   

Prop and engine balancing problems.  

I have found that the Jabiru engines with solid lifters are fairly smooth and the early hydraulic ones run harshly.  I have had both engines in my flying school over the years, both 2.2 engines.  

We have had both the 4 and 6 cylinder hydraulic engines self destruct at about 400-450 hours due to the harshness in the engine (vibration).  The fix is to (A) turn them back into solid lifter engine  (B) replace the cam with the latest 260 cam or (C) a 3 blade prop (wood or composite, hides the vibration, does not stop self destruction). To turn them into solid lifter engines requires the lifter to have a slug fitted and the rockers to have a screw and locknut as per the solid lifter engine.  We have done both a 4 and 6 cylinder engines so far with great results, very smooth running, lower EGT, CHT and oil temps and oh more power.  Fitting the latest cam means taking the engine to pieces, do this with high time engines (say over 400 hours) as you will probably find crankcase wear around the main bearings and cam at the 5-6 cylinder area.  If your engine has broken a through bolt (happened to me on my 4 and a friend with his 6 both above the fuel pump) the crankcases WILL need machining, the engine has just self destructed.  After saying the above I would not have any other engine, the Jabiru is still going through birthing pains and is a great engine.  As a side note I have just ordered a J250 kit, my second kit as I have already built a Lightning.  

   

Anthony  

   

         

  

From: owner-lightning-list-server(at)matronics.com [mailto:owner-lightning-list-server(at)matronics.com] On Behalf Of Brian Whittingham

 Sent: Thursday, 12 November 2009 1:36 AM

 To: lightning-list(at)matronics.com

 Subject: RE: Prop balancing  

  

   

Bill,    

  I too am very interested in your prop balancing.  Perhaps you can write a little something for the newsletter as I believe this would help everybody enjoy their aircraft more and over 1000+ hours is bound to help your engine life and reliability.  Thanks, Brian W.

 

 > Subject: Prop balancing

 > From: bill(at)gdsx.com

 > Date: Wed, 11 Nov 2009 00:50:52 -0800

 > To: lightning-list(at)matronics.com

 > 

 > --> Lightning-List message posted by: "Bill Strahan" <bill(at)gdsx.com>

 > 

 > I fabricated the brackets to mount my dyna-vibe prop balancing sensors to the Jabiru yesterday. I got everything mounted just as I was running out of time, so I only ran the engine briefly to measure vibration at 2000 rpm. I haven't actually gotten to do the balancing part yet.

 > 

 > But the reading was pretty shocking. I was showing .38 IPS at 2000 RPM. That's pretty high. The plane feels very smooth though!

 > 

 > The sensors are mounted directly to the engine so I'm guessing that the smoothness is due in large part to a very effective engine mount and perhaps some natural dampening of the composite fuselage.

 > 

 > My Grumman felt positively buzzy at .26 IPS and felt MUCH less smooth than my Lightning does even though my Lightning is showing a higher vibration level at the engine itself. Once I got the Grumman to .05 IPS it was silky smooth.

 > 

 > So, I'm thinking that when I get the Jabiru down in that range coupled with the obviously better engine vibration isolation in the mount/fuselage of my Lightning that I'll only be able to tell the engine is running by the noise or looking at the EFIS. 

 > 

 > I'll post my results after I actually balance it and test fly it tomorrow.

 > 

 > Bill

 > 

 > 

 > 

 > 

 > Read this topic online here:

 > 

 > http://forums.matronics.com/viewtopic.php?p=272288#272288

 > 

 > 

 > 

 > 

 > 

 > 

 > 

 >=======================

 &g====================

 > 

 > 

 >   

  

       

  

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Bill Strahan

Joined: 20 Aug 2008
Posts: 145

Posted: Wed Nov 11, 2009 9:17 pm Post subject: Re: Prop balancing

 	  mark(at)flylightning.net wrote: 	
		  It's amazing what you can accomplish when you actually take your plane

home!!  



Anybody interested in a nice yellow Grumman?



All in fun.



Mark



-- 	




And here I thought we were friends.  Sniffle sniffle.  



Actually, I was at my hangar today doing misc work and my partner in the Grumman dropped by.  I had him jump in the plane with me and found out I can't shut the canopy with him in it!  He's 6'4" and the canopy hit his head without a headset on!  We pulled the cushions out, and I think he might be okay so if all goes well I'll bring him out once I get my 40 hours and he'll fly the Grumman back.



It sure is nice to have it 20 minutes away.  I can work on the plane during the day and still be home when my kids get home from school.  Perfect!



I also spent some time on the balance and got it down to .18 before I again had to call it a day.  With the accelerometer mounted on the VERY front of the engine it will be very sensitive, so I should be able to achieve that turbine-like smoothness I'm after.



As to other posts on this thread, how can I verify the profile cam that I have on my engine?



Bill

Bill Strahan

Joined: 20 Aug 2008
Posts: 145

Posted: Fri Nov 13, 2009 9:02 pm Post subject: Re: Prop balancing

Finally got back out to the airport and worked on the plane.  My initial numbers were WAY off.  The Dyna-Vibe was getting errant reflections from the shiny spinner backplate and was reading 2-3 times the actual RPM.



Of course, the vibration measurement, in inches per second was reporting a much lower number because it thought the prop was spinning much faster...anyway, long story short the actual vibration was just over 1 IPS!



An even better testimony to the effectiveness of the mount, because that's shaking pretty good.



I had it down to .05 IPS in 15 minutes and life was good.  It's SMOOTH.



If anyone is close to DFW and wants to come by and make use of the mounts I fabricated I'd be happy to accomodate them.



Bill

Bill Strahan

Joined: 20 Aug 2008
Posts: 145

Posted: Fri Nov 13, 2009 9:06 pm Post subject: Re: Prop balancing

 	  8wn(at)comcast.net wrote: 	
		  Bill



Looks like you will have no problem bringing the ips below .07. I have been 

balancing props for a while and would like to have more info from you.

What type of prop? Ground adjustable or fixed?

What type of spinner. Composite or metal?

What engine, solid or hydraulic.

Hours on engine?



I have found much worse  on a Lighting I am working with. Static RPM was 

2675.

First run was 3.5 ips. That is twice as high as any I have ever seen and way 

over the maximum. Prop was pulled, ground adjustable, sent to factory for 

rework and returned.  Next run was about 2.8. Composite spinner was removed 

and vibe was .8+-. Balanced to about .35.  New metal spinner was installed 

and will run a new balance soon.  Engine is solid lifters at about 250 

hours.  I will be doing a balance on my Lightning in the next week.



Hope more will start having their aircraft dynamic balanced. It is worth the 

cost.

Johnny Thompson

--- 	




Sorry, didn't address this sooner.



What type of prop? Ground adjustable or fixed?

   Fixed



What type of spinner. Composite or metal?

   Metal



What engine, solid or hydraulic.

   Hydraulic



Hours on engine?

   32



For what it's worth, it took about 15 grams of weight on the spinner backplate to balance it to .05 IPS.

pennington(at)q.com
Guest

Posted: Sat Nov 14, 2009 3:00 am Post subject: Prop balancing

<?xml:namespace prefix="v" /><?xml:namespace prefix="o" /><![endif]-->  Good morning Johnny

  

 How are things with you?

  

 I'm curious. How much would it cost to balance the prop?

  

 Thanks for your time and have a great day.

  

 Gary Pennington

 [quote]   ---

Bill Strahan

Joined: 20 Aug 2008
Posts: 145

Posted: Sat Nov 14, 2009 7:46 am Post subject: Re: Prop balancing

Cost?  Depends on how much fuel it takes to get to Mckinney, Texas.  



I've got the brackets, and have done this twice now and just enjoyed it.  I'm happy to have any Lightning owner (and one Zenair I know of) come by and I'll help them do it.



It's actually VERY fast once you make the brackets:



1) remove the cowl

2) remove two plugs on the front of the engine (thanks Pete!)

3) mount the brackets there with 5/16-18 bolts

4) run the engine and take a reading.  This reading will provide the vibration in inches per second as well as information to calcualte the angular measurement from the sensor that requires weight to be added

5) if the IPS is too high, add some weight with a washer under a spinner screw and repeate step 4

6) take all the washers off, weigh them, and replace with lead weights inside the spinner

7) the lead will be in a slightly different place than the washers, so do it all again but this time you're just fine tuning with some really small washers to get it to .05 or less

 remove the brackets, replace the plugs with loctite

9) go fly and say "ahhhhhh" and let your headset touch the canopy and say 'wow!"  



Steps 4-7 took me about 15 minutes.



I'll attach a pic of the sensors mounted.

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