VansAirForceForums  
Home > VansAirForceForums

-POSTING RULES
-Advertise in here!
- Today's Posts | Insert Pics

Keep VAF Going
Donate methods

Point your
camera app here
to donate fast.


Go Back   VAF Forums > Model Specific > RV-12/RV-12iS
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 06-06-2021, 03:17 PM
Piper J3's Avatar
Piper J3 Piper J3 is online now
 
Join Date: Nov 2014
Location: Hinckley, Ohio
Posts: 2,424
Default Prop Balance - How Much Weight to Add?

We are balancing a RV-12 prop with DynaVibe. It's our first experience doing this. The unit is telling us 0.4IPS x 50 grams starting point = 20 grams weight.

Does that sound reasonable?
How much weight have folks added for balancing?

Thanks in advance...
__________________
-
Jim Stricker - EAA #499867
PPL/ASEL 1970 - Sport Pilot since 2007
80 hrs Flying Aeronca Chief 11AC N86203
1130 hrs Flying 46 Piper J-3 Cub N6841H
Bought Flying RV-12 #120058 Oct 2015 with 48TT - Hobbs now 670

LSRM-A Certificate 2016 for RV-12 N633CM
Special Thanks... EJ Trucks - USN Crew Chief A-4 Skyhawk
MJ Stricker (Father & CFI) - USAAF 1st Lt. Captain B-17H
Reply With Quote
  #2  
Old 06-06-2021, 03:28 PM
Bob Y Bob Y is online now
 
Join Date: Jul 2017
Location: Piedmont, SC
Posts: 233
Default

See page 32 of the attached I received from the manufacturer. Mine was pretty close to this guide.

https://www.dropbox.com/s/8vhcmufjxc...eller.pdf?dl=0

Remember you’ll be increasing the weight when you move it to the spinner backplate. Since the spinner is ~10” diameter, mounting at 8” gives a nice round increase of 25%.
__________________
Bob Y - builder 12iS E-LSA
N569TT first flight 2/9/2020
Reply With Quote
  #3  
Old 06-06-2021, 03:50 PM
Piper J3's Avatar
Piper J3 Piper J3 is online now
 
Join Date: Nov 2014
Location: Hinckley, Ohio
Posts: 2,424
Default

Right... what I'm wondering is how much weight folks have used to balance the Sensenich ground adjustable prop on RV-12. I'd like to see if we are in ballpark...
__________________
-
Jim Stricker - EAA #499867
PPL/ASEL 1970 - Sport Pilot since 2007
80 hrs Flying Aeronca Chief 11AC N86203
1130 hrs Flying 46 Piper J-3 Cub N6841H
Bought Flying RV-12 #120058 Oct 2015 with 48TT - Hobbs now 670

LSRM-A Certificate 2016 for RV-12 N633CM
Special Thanks... EJ Trucks - USN Crew Chief A-4 Skyhawk
MJ Stricker (Father & CFI) - USAAF 1st Lt. Captain B-17H
Reply With Quote
  #4  
Old 06-06-2021, 04:23 PM
Bob Y Bob Y is online now
 
Join Date: Jul 2017
Location: Piedmont, SC
Posts: 233
Default

As a reference, I used 36.8 g on the spinner perimeter - 46 g on the 8” diameter.
__________________
Bob Y - builder 12iS E-LSA
N569TT first flight 2/9/2020
Reply With Quote
  #5  
Old 06-06-2021, 04:35 PM
seagull seagull is online now
 
Join Date: Dec 2019
Location: San Bernardino
Posts: 312
Default

Jim,

I ended up with about 19g on the back plate of my -12, drilled at a 9" diameter to get .03ips

Friday I did a Lycoming 320 with a Hartzell 2 blade. With no weight is was .43ips. The finished solution was 17.8g on a 10" diameter to get .04ips.
__________________
Live as if you were to die tomorrow. Learn as if you were to live forever.
-- Walt --

Last edited by seagull : 06-06-2021 at 04:38 PM.
Reply With Quote
  #6  
Old 06-06-2021, 05:19 PM
Tony_T's Avatar
Tony_T Tony_T is offline
 
Join Date: Dec 2008
Location: Lacey, WA
Posts: 1,411
Default RV-12 Sensenich - DynaVibe

Mine was 19.4 grams at the 9" diameter, for 0.08 ips final.
__________________
Tony
E-LSA RV-12 ULS
SkyView Touch

Last edited by Tony_T : 06-07-2021 at 11:07 AM.
Reply With Quote
  #7  
Old 06-06-2021, 10:59 PM
RFSchaller RFSchaller is offline
 
Join Date: Oct 2010
Location: Phoenix, AZ
Posts: 3,067
Default

The guy who did mine added one #6 machine screw to the spinner bulkhead. Hardly seemed worth the effort.
Reply With Quote
  #8  
Old 06-07-2021, 11:02 AM
rcarsey's Avatar
rcarsey rcarsey is offline
 
Join Date: Jul 2012
Location: North Brunswick, NJ
Posts: 235
Default

my buddy ended up adding just 1 washer under an existing spinner #8 screw. His readings were fairly good to begin with.

On mine, I started with 0.30-0.34 IPS and ended up adding 13g at a hole that was appox 3/4" from the spinner backplate edge. End result was about 0.04 IPS

Incidentally, I rent out my DynaVibe for $100 to any builder that needs it (up to a maximum of $1400.. as I'm looking only to recoup costs and not make money off it)
__________________
Rob Carsey, North Brunswick NJ
RV-12iS (N713) / Completed 12/2020
ASEL, Glider, AGI/IGI, LSRM-I, FCC GROL
Reply With Quote
  #9  
Old 06-07-2021, 12:33 PM
bobg56 bobg56 is offline
 
Join Date: Nov 2018
Location: Peachtree City, GA
Posts: 177
Default

Mine was .50 after adding 27 grams it came down to .05 I used a 1/4" NAS bolt and 2 OD washers and lock nut to mid span of spinner bulkhead 180 degrees opposite of heavy spot...piece of cake.
Reply With Quote
  #10  
Old 06-16-2021, 03:19 PM
Mike Howard Mike Howard is offline
 
Join Date: Jan 2006
Location: Omaha, NE.
Posts: 7
Cool gram scale

I just finished balancing the Sensenich prop on my RV12. before the balance it registered .17 in/sec after balance we got it down to .05 in/sec.
Now the rub! I added one #8 x 1/2" screw with a nylon lock nut at 4.5" from the center of the shaft. My gram scale said that the screw and nut only weighed 3.8 grams. Everyone else seems to be coming up with much higher weights to do the balance.
I hope the scale is not wrong because it is the same one I use to weigh the carburetor floats and they came in at 6.7 grams for each pair.
Any thoughts?
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 08:17 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.