VansAirForceForums  
Home > VansAirForceForums

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

Keep VAF Going
w/a Donation






VAF on Twitter:
@VansAirForceNet

  #11  
Old 05-14-2023, 03:09 PM
BillL's Avatar
BillL BillL is offline
 
Join Date: Sep 2007
Location: Central IL
Posts: 7,104
Default

Jeff, tough issue - -
You did not ask, but I would select an easy out that could be attached to a 10mm bar to turn it, then make a drill guide sleeve and insert in the hole to drill to an appropriate depth for that tool. Might even see if an extended length of a left turning bit were available to do the job. Then after drilling and cleaning back out the stub. 90% chance that it is not stuck, just fatigued and failed.

I just looked and only found 6" aviation RH bits, but might experiment and silver braze a bit in a long rod for an extension to "make" a left hand bit. Might have to do the same for the screw extractor.

If it is a case bolt, then a good discussion regarding potential case shear and fretting. Even so - -if not leaking and after removing the tip, if the free movement of the crank remains then would leave it. The crank motion should be checked at TDC so piston/ring friction is not included.

May luck be with you!!
__________________
Bill
RV-7
Reply With Quote
  #12  
Old 05-14-2023, 08:34 PM
Jeff Vaughan's Avatar
Jeff Vaughan Jeff Vaughan is offline
 
Join Date: Jan 2005
Location: West Chester, Pa
Posts: 620
Default

Thanks for the great suggestions. Keep them coming!
__________________
Jeff Vaughan
RV 12 N237VW ELSA
Northwing Navajo Trike N561VW
RV 7A N561EV Sold
West Chester Pa

2023 donation current
Reply With Quote
  #13  
Old 05-15-2023, 10:58 AM
azonslow azonslow is offline
 
Join Date: Mar 2017
Location: Maricopa County, AZ
Posts: 31
Default Sheared Bolt

Jeff, check your PMs.
Reply With Quote
  #14  
Old 05-15-2023, 10:22 PM
RFSchaller RFSchaller is offline
 
Join Date: Oct 2010
Location: Phoenix, AZ
Posts: 3,393
Default

Might be a substandard bolt that got into inventory as opposed to in service conditions.
Reply With Quote
  #15  
Old 05-15-2023, 10:56 PM
rgmwa rgmwa is offline
 
Join Date: Feb 2010
Location: Perth, Western Australia
Posts: 1,751
Default

Possibly not fully torqued originally leading to fatigue failure?
__________________
RV-12LR 912ULS 120346
Reply With Quote
  #16  
Old 05-16-2023, 04:01 AM
Piper J3's Avatar
Piper J3 Piper J3 is offline
 
Join Date: Nov 2014
Location: Hinckley, Ohio
Posts: 2,927
Default

When a bolt is torqued to correct value then any cyclic tension forces, less than the pre-stretched tension, are not seen by the bolt. Conversely, if a bolt is under less than designed pre-stretched tension then it sees repeated forces that lead to failure. This is why cylinder head bolts and connecting rod cap bolts never fail if torqued correctly.

Another possibility is wrong grade bolt was used. Metric cap screws come in different grades. Grade 8 has less tensile strength then grade 12.
__________________
-
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 850

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
  #17  
Old 05-16-2023, 09:13 AM
azonslow azonslow is offline
 
Join Date: Mar 2017
Location: Maricopa County, AZ
Posts: 31
Default Engine mounting bolt sheared

Rotax MMH from September 2022 states that the M10x110 bolt must be of strength category 10.9 and goes on to specify that the bolt is torqued to 44 ft. lbs. using LOCTITE 243. See 71-00-00 page 20
Reply With Quote
  #18  
Old 05-16-2023, 12:55 PM
Bob Y Bob Y is online now
 
Join Date: Jul 2017
Location: Piedmont, SC
Posts: 502
Default

Quote:
Originally Posted by azonslow View Post
Rotax MMH from September 2022 states that the M10x110 bolt must be of strength category 10.9 and goes on to specify that the bolt is torqued to 44 ft. lbs. using LOCTITE 243. See 71-00-00 page 20
Hmm. That’s interesting…. The same size, and 10.9 grade, bolts are used on the 12iS mount, yet the MMH for the iS (71-00-00, p 24) says to tighten to only 29.5 ft-lbs (40 Nm vs. 60 Nm). Big difference. Wondering why?
__________________
Bob Y - builder 12iS
N569TT first flight 2/9/2020
#121047

Last edited by Bob Y : 05-17-2023 at 09:00 AM.
Reply With Quote
  #19  
Old 05-16-2023, 02:32 PM
azonslow azonslow is offline
 
Join Date: Mar 2017
Location: Maricopa County, AZ
Posts: 31
Default

I'm confused also. I've looked at the latest MMH for 912iS that I could find and the torque value is 29.5 (sometimes in NM) with no mention of LOCTITE. The iS MMHs are older than the September 2022 912ULS one I cited. This is what the MMH I cited said at the bottom of each page: "Effectivity: 912/914 Series" Maybe in Rotax speak that means all 912/914. Maybe Scott from Vans can help us out here.
Reply With Quote
  #20  
Old 05-16-2023, 07:10 PM
Bob Y Bob Y is online now
 
Join Date: Jul 2017
Location: Piedmont, SC
Posts: 502
Default

If we canít get an authoritative answer here, I can post the question on the Rotax Owners forum.
__________________
Bob Y - builder 12iS
N569TT first flight 2/9/2020
#121047
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 12:06 PM.


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.