|
-
POSTING RULES

-
Donate yearly (please).
-
Advertise in here!
-
Today's Posts
|
Insert Pics
|

02-12-2012, 08:35 PM
|
 |
|
|
Join Date: Sep 2010
Location: Redlands, Ca.
Posts: 1,458
|
|
Quote:
Originally Posted by erich weaver
Wow, wish I had this a few days ago. Think I want one for next time. One question Alan:
You mention in the video that the 3inch length results in a multiplier of 0.8 to get the torque value. Is this true regardless of the toque wrench used? If so, this seems to imply that all toque wrenches are the same length. Is that really true?
Thanks,
Erich
|
Hi Erich;
The torque wrench measures foot pounds. The prop tool we made if installed on the torque wrench in a straight line increases the torque arm. To make the readings come out correct the .8 multiplier is used. Am alternative method is to install the prop wrench on the torque wrench at a 90 degree angle and use no multiplier as nothing will be dimensionally any different. All torque wrenches aren't the same length but the length change only effects how hard you need to pull to get to your desired number. All foot pound torque wrenches are the same in function and measure foot pounds regardless of their overall length. Thanks, Allan 
__________________
Allan Nimmo
AntiSplatAero.com
Innovative Aircraft Safety
Products, Tools & ServicesInfo@AntiSplatAero.com Southern California (KREI)
RV-9A / Edge-540 
(909) 824-1020
|

02-12-2012, 08:42 PM
|
 |
|
|
Join Date: Jan 2005
Location: Santa Rosa, CA
Posts: 216
|
|
Whirlwind?
Hi,
This looks like a great tool. Will it work on the Whirlwind prop too?
__________________
Craig Schwartz
RV-8 (Flying!), IO-360B1PC2 (180 hp, 1 P-Mag, 1 Slick Mag), Whirlwind 200RV, AF-3500, G496, Digiflight II, Classic Aero Sportsman Ultraleather Seats
N868RV
Santa Rosa, CA
|

02-12-2012, 08:50 PM
|
 |
|
|
Join Date: Sep 2010
Location: Redlands, Ca.
Posts: 1,458
|
|
Quote:
Originally Posted by Craig23
Hi,
This looks like a great tool. Will it work on the Whirlwind prop too?
|
Yes! The WW prop is a Hartzell compact hub or exact copy of one. That is what I have on my airplane and is the same hub as in the video. Thanks, Allan
__________________
Allan Nimmo
AntiSplatAero.com
Innovative Aircraft Safety
Products, Tools & ServicesInfo@AntiSplatAero.com Southern California (KREI)
RV-9A / Edge-540 
(909) 824-1020
|

02-13-2012, 05:48 AM
|
 |
|
|
Join Date: Aug 2005
Location: Dallas/Ft Worth, TX
Posts: 5,687
|
|
Quote:
Originally Posted by PerfTech
Hi Erich;
The torque wrench measures foot pounds. The prop tool we made if installed on the torque wrench in a straight line increases the torque arm. To make the readings come out correct the .8 multiplier is used. Am alternative method is to install the prop wrench on the torque wrench at a 90 degree angle and use no multiplier as nothing will be dimensionally any different. All torque wrenches aren't the same length but the length change only effects how hard you need to pull to get to your desired number. All foot pound torque wrenches are the same in function and measure foot pounds regardless of their overall length. Thanks, Allan 
|
Allan,
Looks like a great tool, already placed my order. However, I'm no math wiz but what you're saying contradicts the standard formula when using an extension:
Wrench setting = desired torque x wrench length / (wrench length + extension length)
So I guess I don't get it either 
__________________
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
|

02-13-2012, 06:09 AM
|
|
|
|
Join Date: May 2011
Location: Atlanta, GA
Posts: 240
|
|
Torque multiplier
The torque is accurately applied at the end of the torque wrench. Since while using this tool the torque wrench is actually 3" from the bolt you are torquing, there is an additional 3" moment arm to factor into the equation. Converting the 3" to feet (so as to apply accurately to the the "foot pound" units used) gives 3/12 which is .75 which they round to .8.
If you need to torque a bolt to 100 ft/lb and your wrench is one foot long, you will need to apply 100 pounds to the handle to reach the value. If your torque wrench was 2 feet long you only need apply 50 lbs of force to the handle to reach the same torque. The wrench scale is calibrated for the length.
Since you are introducing additional moment arm, you must manually account for this or you will end up overtorquing by this 25%. In this case you would set your torque wrench to 75 ft/lb when using the prop wrench. When the torque wrench indicates 75 ft/lb of torque, the bolt will be at 100 ft/lb.
__________________
RV4
|

02-13-2012, 08:09 AM
|
 |
|
|
Join Date: Aug 2006
Location: santa barbara, CA
Posts: 1,682
|
|
Still confused
Last I checked, 3/12 is not 0.75
Erich
|

02-13-2012, 08:28 AM
|
 |
|
|
Join Date: Sep 2007
Location: WA
Posts: 988
|
|
Example was for a 12 inch wrench length...
Wrench torque = desired bolt torque * (wrench length / total length)
For a wrench length (to the handle centerline) of 12" with a 3" extension you have (12 / 15) or .8
__________________
Stephen
RV7 powered by a lycoming thunderbolt IO-390
turning a whirlwind HRT prop
with more hours flying than building... 2,430 on the hobbs!
ORCA Flight
Race 771
margarita!
|

02-13-2012, 09:11 AM
|
 |
|
|
Join Date: Jul 2007
Location: Delta, CO/Atlin, BC
Posts: 2,391
|
|
I agree with Walt, the angle at which the wrench attaches to the torque wrench should make no difference - the multiplier should stay the same regardless of the angle. You still have a 15" arm rather than the standard 12" arm.
Edit: I stand corrected, the angle DOES matter.
Greg
__________________
Greg Arehart
RV-9B (Big tires) Tipup @AJZ or CYSQ
N 7965A
Last edited by Greg Arehart : 02-14-2012 at 07:48 AM.
|

02-13-2012, 10:31 AM
|
|
|
|
Join Date: Aug 2005
Location: Grass Lake, MI
Posts: 128
|
|
Does it work on MT 3 blade RV-10 props?
-Mike
|

02-13-2012, 10:46 AM
|
 |
Senior Curmudgeon
|
|
Join Date: Sep 2005
Location: Dayton Airpark, NV A34
Posts: 15,420
|
|
Quote:
Originally Posted by schristo@mac.com
Wrench torque = desired bolt torque * (wrench length / total length)
For a wrench length (to the handle centerline) of 12" with a 3" extension you have (12 / 15) or .8
|
Correct.
Total new length assuming the wrench starts at 12", becomes 15".
Try working the problem from the other direction, multiply the arm of 15" times .8.
See what you get.
Here is one other--------- 100# x 12" = 1200in/lb. 80# x 15"= 1200in/lb.
__________________
Mike Starkey
VAF 909
Rv-10, N210LM.
Flying as of 12/4/2010
Phase 1 done, 2/4/2011 
Sold after 240+ wonderful hours of flight.
"Flying the airplane is more important than radioing your plight to a person on the ground incapable of understanding or doing anything about it."
|
| Thread Tools |
Search this Thread |
|
|
|
| Display Modes |
Linear Mode
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
All times are GMT -6. The time now is 09:15 AM.
|