VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics


Go Back   VAF Forums > The Never Ending Debate Section > Tools
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #11  
Old 02-12-2012, 08:35 PM
PerfTech's Avatar
PerfTech PerfTech is offline
 
Join Date: Sep 2010
Location: Redlands, Ca.
Posts: 1,458
Default

Quote:
Originally Posted by erich weaver View Post
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 & Services
Info@AntiSplatAero.com
Southern California (KREI)
RV-9A / Edge-540
(909) 824-1020
Reply With Quote
  #12  
Old 02-12-2012, 08:42 PM
Craig23's Avatar
Craig23 Craig23 is offline
 
Join Date: Jan 2005
Location: Santa Rosa, CA
Posts: 216
Default 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
Reply With Quote
  #13  
Old 02-12-2012, 08:50 PM
PerfTech's Avatar
PerfTech PerfTech is offline
 
Join Date: Sep 2010
Location: Redlands, Ca.
Posts: 1,458
Default

Quote:
Originally Posted by Craig23 View Post
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 & Services
Info@AntiSplatAero.com
Southern California (KREI)
RV-9A / Edge-540
(909) 824-1020
Reply With Quote
  #14  
Old 02-13-2012, 05:48 AM
Walt's Avatar
Walt Walt is offline
 
Join Date: Aug 2005
Location: Dallas/Ft Worth, TX
Posts: 5,687
Default

Quote:
Originally Posted by PerfTech View Post
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
Reply With Quote
  #15  
Old 02-13-2012, 06:09 AM
Skysailor Skysailor is offline
 
Join Date: May 2011
Location: Atlanta, GA
Posts: 240
Default 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
Reply With Quote
  #16  
Old 02-13-2012, 08:09 AM
erich weaver's Avatar
erich weaver erich weaver is offline
 
Join Date: Aug 2006
Location: santa barbara, CA
Posts: 1,682
Default Still confused

Last I checked, 3/12 is not 0.75

Erich
Reply With Quote
  #17  
Old 02-13-2012, 08:28 AM
schristo@mac.com's Avatar
schristo@mac.com schristo@mac.com is offline
 
Join Date: Sep 2007
Location: WA
Posts: 988
Default 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!
Reply With Quote
  #18  
Old 02-13-2012, 09:11 AM
Greg Arehart's Avatar
Greg Arehart Greg Arehart is offline
 
Join Date: Jul 2007
Location: Delta, CO/Atlin, BC
Posts: 2,391
Default

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.
Reply With Quote
  #19  
Old 02-13-2012, 10:31 AM
mkraus01 mkraus01 is offline
 
Join Date: Aug 2005
Location: Grass Lake, MI
Posts: 128
Default

Does it work on MT 3 blade RV-10 props?
-Mike
Reply With Quote
  #20  
Old 02-13-2012, 10:46 AM
Mike S's Avatar
Mike S Mike S is online now
Senior Curmudgeon
 
Join Date: Sep 2005
Location: Dayton Airpark, NV A34
Posts: 15,420
Default

Quote:
Originally Posted by schristo@mac.com View Post
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."
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 09:15 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.