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  #1  
Old 12-29-2010, 11:23 AM
Alex D Alex D is offline
 
Join Date: Jan 2005
Location: Dallas, TX
Posts: 114
Default Thanks EXP AIRCRAFT

Walt, just wanted to thank you for a great job balancing my propeller.

Last Sunday took the RV7 up for a test flight and it is smooooooth!

Thanks Again
Alex
www.RVTraining.com
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  #2  
Old 12-29-2010, 08:37 PM
Walt's Avatar
Walt Walt is offline
 
Join Date: Aug 2005
Location: Dallas/Ft Worth, TX
Posts: 5,840
Default Dynamic Prop Balancing

Thanks for the feedback Alex

When you fly the 10 you should definately notice the difference, it wasn't as bad as the 7 but the 6 cyl motors really benefit from balancing due to their inherently smoother operation.
__________________
Walt Aronow, DFW, TX (52F)

EXP Aircraft Services LLC
Specializing in RV Condition Inspections, Maintenance, Avionics Upgrades
Dynamic Prop Balancing, Pitot-Static Altmeter/Transponder Certification
FAA Certified Repair Station, AP/IA/FCC GROL, EAA Technical Counselor
Authorized Garmin G3X Dealer/Installer
RV7A built 2004, 1700+ hrs, New Titan IO-370, Bendix Mags
Website: ExpAircraft.com, Email: walt@expaircraft.com, Cell: 972-746-5154
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  #3  
Old 12-30-2010, 12:07 AM
Bob Axsom Bob Axsom is offline
 
Join Date: Mar 2005
Posts: 5,685
Default Glad to hear the good report

Walt's process is reported to be better than the one I experienced at Hartzell. I am going through my 4 page annual condition inspection and I have now got the spinner off to inspect and lube the prop. I looked at the screw, nut and wiecht plate on the aft spinner bulkhead that was not checked for dynamic balance after installation for the purpose of dynamic balancing the system. It performs ok but I have a hard time believing in the actual results. Walt rechecks after the weight is added. I guess I would like to know Walt, what are your findings on the after balance check. If you have complete records - you know hard data - I would like to know the numbers.

Bob Axsom
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  #4  
Old 12-30-2010, 07:49 AM
Walt's Avatar
Walt Walt is offline
 
Join Date: Aug 2005
Location: Dallas/Ft Worth, TX
Posts: 5,840
Default Dynamic Balacing

Bob, I have hard numbers for every balance I do and provide that data to every customer. I'm not quite as computer savy as our host DR or I would post the actual plots, but here are the numbers for Alex's 7 & 10.

RV7: 4 Runs: .132, .048, .025. .035
RV10: 3 Runs: .069, .009, .014

Alex's aircraft were somewhat unique for RV's as they both had custom flywheels to support air conditioning so I had to drill and install weights on the spinner bulkheads on both aircraft. As you can see from the above numbers the final run with the single weight installed increased by .01 IPS for the RV7 and .05 for the RV10 (sometimes it goes down but you never know until you check). The final position/weight is calculated from the 2 weights temporarily installed on the spinner screws. When you change the radius and move them aft to the bulkhead things will change. I strive to keep the final IPS number less than .04 and I know when I calculate a move to the bulkhead there is the possibility for some error so I work to get the number a bit lower to allow for this.

When you can use the Lycoming flywheel to install weights its easier and more accurate to split the weights on the flywheel and easier to tweak.

When installing on the bulkhead I prefer to calculate a single weight positiion so you only drill a single hole, but this will always be a bit of a compromise as there is no way to tweak it (if someone really wanted to tweak it as low as possible then you could drill 2 positions on the bulkhead and split the weights). However, in reality once the balance is in the .03 IPS range or less you really aren't gaining much to go to .02 IPS.

Keep in mind that most Prop shops that do balancing call it quits when they get to .1 IPS which is the industry "standard" upper limit after balancing. Being that I'm self employed, not in a hurry, enjoy doing this and pride myself in precision I'm not personally satisfied until I've taken the time and have done the best job possible which means I don't quit until I have gotten to at least half the industry standard or less (usually less). My average balance generally ends up in the .025-.035 range but I do love it when I get them in the .014 range like we did on Alex's RV10
__________________
Walt Aronow, DFW, TX (52F)

EXP Aircraft Services LLC
Specializing in RV Condition Inspections, Maintenance, Avionics Upgrades
Dynamic Prop Balancing, Pitot-Static Altmeter/Transponder Certification
FAA Certified Repair Station, AP/IA/FCC GROL, EAA Technical Counselor
Authorized Garmin G3X Dealer/Installer
RV7A built 2004, 1700+ hrs, New Titan IO-370, Bendix Mags
Website: ExpAircraft.com, Email: walt@expaircraft.com, Cell: 972-746-5154

Last edited by Walt : 12-30-2010 at 08:31 AM.
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  #5  
Old 12-30-2010, 12:24 PM
Bob Axsom Bob Axsom is offline
 
Join Date: Mar 2005
Posts: 5,685
Default Thanks for the information

Physically you know there has to be some ... "difference" between the test weight test and the actual fixed weight test. I'm sure Hartzell focused on doing a good job - I was there participating - but the lack of final test after fixing the weight bugged me. Your information tells me that my ballance is probably OK but the lack of verification still bugs me in a procedural way.

Bob Axsom
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  #6  
Old 12-30-2010, 12:35 PM
Louise Hose's Avatar
Louise Hose Louise Hose is offline
 
Join Date: Sep 2005
Location: Dayton, Nevada --- A34
Posts: 1,469
Thumbs up I noticed a positive difference with Mikey

Walt,
I just wanted to add to the praise on your prop balances. I was on the oil spill and didn't have a chance to fly the -6 for awhile after the balance. When I did, I could notice a very nice improvement in the smoothness. Thanks!
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Louise Hose, Editor of The Homebuilder's Portal by KITPLANES
RV3B, NX13PL "Tsamsiyu" co-builder, TMXIO-320, test platform Legacy G3X/TruTrak avionics suite
RV-6 ?Mikey? (purchased flying) ? Garmin test platform (G3X Touch, GS28 autopilot servos, GTN650 GPS/Nav/Comm,
GNC255 Nav/Com, GA240 audio panel)
RV8, N188PD "Valkyrie" (by marriage)
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  #7  
Old 12-30-2010, 02:17 PM
Walt's Avatar
Walt Walt is offline
 
Join Date: Aug 2005
Location: Dallas/Ft Worth, TX
Posts: 5,840
Default

Quote:
Originally Posted by Bob Axsom View Post
Physically you know there has to be some ... "difference" between the test weight test and the actual fixed weight test. I'm sure Hartzell focused on doing a good job - I was there participating - but the lack of final test after fixing the weight bugged me. Your information tells me that my ballance is probably OK but the lack of verification still bugs me in a procedural way.

Bob Axsom
You're "Probably" right, but honestly I would never even consider not doing a final confirmation run, it doesn't take much of a miscalculation to throw things way out. As you can see from the numbers above even doing a "perfect" mathmatical calculation it still changed on the final run.

Quote:
Originally Posted by Louise Hose View Post
Walt,
I just wanted to add to the praise on your prop balances. I was on the oil spill and didn't have a chance to fly the -6 for awhile after the balance. When I did, I could notice a very nice improvement in the smoothness. Thanks!
Thanks Louise, Paul still needs to bring his 8 up here so we can get it done
__________________
Walt Aronow, DFW, TX (52F)

EXP Aircraft Services LLC
Specializing in RV Condition Inspections, Maintenance, Avionics Upgrades
Dynamic Prop Balancing, Pitot-Static Altmeter/Transponder Certification
FAA Certified Repair Station, AP/IA/FCC GROL, EAA Technical Counselor
Authorized Garmin G3X Dealer/Installer
RV7A built 2004, 1700+ hrs, New Titan IO-370, Bendix Mags
Website: ExpAircraft.com, Email: walt@expaircraft.com, Cell: 972-746-5154
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  #8  
Old 01-06-2011, 11:44 PM
Walt's Avatar
Walt Walt is offline
 
Join Date: Aug 2005
Location: Dallas/Ft Worth, TX
Posts: 5,840
Default Check that Prop!

Here's a good reason to get your vibration checked, had this one drop in today and the owner just had the prop redone by a local prop shop and he thought it had "a little" more vibration than it used to. Vibs were 1.45 IPS (upper limit is 0.2 IPS).

This was the first time I'd ever seen one this high and it set off an alarm on the balancer to immediately warn the operator (Danger Will Robinson).

Basically this aircraft was in an unsafe condition to fly and I told the owner he needed to immediately remove the prop and return it to the shop to have the static balance checked. He told me that the static weights that used to be on the prop were not there when he got it back after rework and he thought that was unusual, but he installed it anyway, bad move (he is an A&P also).

Note the small red circle in the middle is the upper limit after balance of 0.1 IPS.

__________________
Walt Aronow, DFW, TX (52F)

EXP Aircraft Services LLC
Specializing in RV Condition Inspections, Maintenance, Avionics Upgrades
Dynamic Prop Balancing, Pitot-Static Altmeter/Transponder Certification
FAA Certified Repair Station, AP/IA/FCC GROL, EAA Technical Counselor
Authorized Garmin G3X Dealer/Installer
RV7A built 2004, 1700+ hrs, New Titan IO-370, Bendix Mags
Website: ExpAircraft.com, Email: walt@expaircraft.com, Cell: 972-746-5154
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  #9  
Old 01-07-2011, 05:09 PM
flyindoorman flyindoorman is offline
 
Join Date: Apr 2009
Location: San Antonio, Texas
Posts: 134
Default Cost

Walt

If i fly my RV10 up to Ft Worth about what is the cost for doing a prop balance ?
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Randy
N38DG RV7
N204GS RV10 Traded
N63AZ Harmon Rocket II Purchased and flyingSold
N433RV sold
RV10
Dues paid 2020
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  #10  
Old 01-07-2011, 05:25 PM
Walt's Avatar
Walt Walt is offline
 
Join Date: Aug 2005
Location: Dallas/Ft Worth, TX
Posts: 5,840
Default

Cost is $150 for my all VAF RV friends

More info on my website.
__________________
Walt Aronow, DFW, TX (52F)

EXP Aircraft Services LLC
Specializing in RV Condition Inspections, Maintenance, Avionics Upgrades
Dynamic Prop Balancing, Pitot-Static Altmeter/Transponder Certification
FAA Certified Repair Station, AP/IA/FCC GROL, EAA Technical Counselor
Authorized Garmin G3X Dealer/Installer
RV7A built 2004, 1700+ hrs, New Titan IO-370, Bendix Mags
Website: ExpAircraft.com, Email: walt@expaircraft.com, Cell: 972-746-5154
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