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  #31  
Old 09-22-2022, 11:38 AM
lr172 lr172 is offline
 
Join Date: Oct 2013
Location: Schaumburg, IL
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Quote:
Originally Posted by Flying Canuck View Post
I went out to check tonight and yes, it does look like the roll pins go all the way through. Most of them are completely or nearly completely blocked. I'm attaching some pictures I took of 3 of them, I can see light easily through one - the same one I'd actually been able to get a wire through - the others not at all at any camera angle.

I tried backing off and feeding the safety wire and had no success whatsoever. I don't see any way that I can physically safety these bolts. Unfortunately these are not field replaceable. We backed off all 6 bolts and torqued them to the specified 47 ft-lb. Very secure. I'm inclined to fly them like that and ensure that I get a torque wrench on them every 50 hours which is the specified interval. Although I think it's an error, but the installation manual doesn't say anything about safety wiring the flange bolts on a 2 piece rear bulkhead (it does for the single piece) - it doesn't say anything about installing the bolts either though.
Look closely at Pic #4. I can see what appears to be a kink/bend in the pin's wall right where the nut and stud meet. IMHO, those pins should have been installed with the split oriented perpendicular to the load transfer direction of the nut/stud. The way they are oriented, there is only one solid side of the pin to take the tightening load that is transferred via the pin from the nut to the stud. The other side has the split and that makes it substantially weaker. When installed 90* from there current orientation, there would have been two solid wall surfaces to take the load. I would get in there with more light and magnification to see if the pins really have kinked / bent wall surfaces.

If they do have bends, you should be able to replace the tension pins yourself. No special tooling or skill required to install tension pins, just a proper sized punch. You will need to drive them from outside to in and that will likely require you to drive it some, cut off the exposed then rinse / repeat until it is out.

Larry
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Last edited by lr172 : 09-22-2022 at 11:51 AM.
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  #32  
Old 09-22-2022, 12:21 PM
Flying Canuck Flying Canuck is offline
 
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Location: Red Deer, Alberta, Canada
Posts: 696
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I spoke with WW today, the main guy is out this week but they're relaying to him. The roll pins are replaced during the teardown that was just done, so they should be clear. They'll work with me to get that fixed and if the prop needs to go back to them, it will be at their expense.
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Claude Pitre
RV-9A #91081, C-GCPT
Dynon SkyView HDX, IO-320 and WW 200RV C/S. Flying as of August 6, 2018

Added GPS 175 and authorized for IFR April 1, 2021

Interactive map of all of my flights here
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  #33  
Old 09-22-2022, 01:27 PM
rockwoodrv9 rockwoodrv9 is offline
 
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Location: Meridian ID, Aspen CO, Okemos MI
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Quote:
Originally Posted by Flying Canuck View Post
I went out to check tonight and yes, it does look like the roll pins go all the way through. Most of them are completely or nearly completely blocked. I'm attaching some pictures I took of 3 of them, I can see light easily through one - the same one I'd actually been able to get a wire through - the others not at all at any camera angle.

I tried backing off and feeding the safety wire and had no success whatsoever. I don't see any way that I can physically safety these bolts. Unfortunately these are not field replaceable. We backed off all 6 bolts and torqued them to the specified 47 ft-lb. Very secure. I'm inclined to fly them like that and ensure that I get a torque wrench on them every 50 hours which is the specified interval. Although I think it's an error, but the installation manual doesn't say anything about safety wiring the flange bolts on a 2 piece rear bulkhead (it does for the single piece) - it doesn't say anything about installing the bolts either though.
I may not be seeing the right things but with the pin going through the bolt, isnt that acting as a carter pin and not allowing the nut to turn? I have never seen pins through bolts so I dont understand how they work.
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  #34  
Old 09-22-2022, 01:28 PM
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jliltd jliltd is offline
 
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Location: Rancho San Lorenzo
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Quote:
Originally Posted by Flying Canuck View Post
This is second time on for the prop, installed and wired in 2017. Hasn't been any drilling in the vicinity since first installation and all safety wire was removed when I pulled the prop off in July. Not to say that there isn't debris, just that I have no explanation for it.
When the prop manufacturer does maintenance they usually strip off everything, including the roll pins and nuts on the studs. So while it worked great back in 2017 that doesn't matter since Whirlwind just removed the roll pins, nuts and reinstalled them. So something is up.
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  #35  
Old 09-22-2022, 01:48 PM
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hgerhardt hgerhardt is offline
 
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Location: torrance, ca
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Learned one thing from this: the bolts are easier to access than on a Hartzell...

I agree that the roll pins can be field-replaced and to me would be better than shipping the prop back and forth again. I am not convinced that installing the new pins 90deg from where the current ones are is better.

The question is what's the condition of the threads in the crankshaft flange? If there's any residue in there (anti-seize, Loctite, oxidized oil, crud, etc) that could cause enough thread friction to twist off the roll pins. I'd chase the threads with a tap to clean them, using WD-40 to help remove the crud.

Last edited by hgerhardt : 09-22-2022 at 01:51 PM.
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  #36  
Old 09-23-2022, 05:28 AM
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dmattmul dmattmul is offline
 
Join Date: Dec 2015
Location: Spring Hill, FL
Posts: 564
Default Torquing the prop nuts

Iíve not seen it referenced on VAF and maybe I missed it or just common since but when using the ultimate torque wrench make sure you use it 90 degrees to the bar as increasing or decreasing the length will throw off the actual amount of torque used. If thatís not correct feel free to chime in. Obviously important we get the correct torque.
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  #37  
Old 09-23-2022, 08:53 AM
Flying Canuck Flying Canuck is offline
 
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Location: Red Deer, Alberta, Canada
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Quote:
Originally Posted by dmattmul View Post
Iíve not seen it referenced on VAF and maybe I missed it or just common since but when using the ultimate torque wrench make sure you use it 90 degrees to the bar as increasing or decreasing the length will throw off the actual amount of torque used. If thatís not correct feel free to chime in. Obviously important we get the correct torque.
You are correct, I am using the Anti Splat Aero Ultimate Propeller Wrench and have my torque wrench at 90 degree to avoid having to recalculate the required torque.
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Claude Pitre
RV-9A #91081, C-GCPT
Dynon SkyView HDX, IO-320 and WW 200RV C/S. Flying as of August 6, 2018

Added GPS 175 and authorized for IFR April 1, 2021

Interactive map of all of my flights here
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  #38  
Old 09-23-2022, 10:02 AM
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jliltd jliltd is offline
 
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Location: Rancho San Lorenzo
Posts: 1,387
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The torque correction based on extender length is a simple ratio. If an extender is set 90 degrees the arm does change by the diagonal hypotenuse distance. So a math calculation will be more accurate. For the Anti-splat wrench that’s probably not significant due to its short hypotenuse length combined with real world wrench reading tolerance.

The fancy new digital torque wrenches allow the user to enter the extender length and then automatically do the math. Nice, but the math is so easy that’s not a single feature worth the upgrade cost.
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  #39  
Old 09-25-2022, 02:01 PM
Flying Canuck Flying Canuck is offline
 
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Location: Red Deer, Alberta, Canada
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I'm still fighting with this, I talked to the specialist at Whirlwind on Friday and he told me that they didn't touch the roll pins - even though their website lists their replacement at the top of the list of items done during the tear down. I'll be talking to him again tomorrow when he returns to the shop, he was out last week. I'm hoping they'll agree to working with a prop shop here in Alberta to get this fixed.

I'm attaching one more picture that turned out really sharp. When I was removing the prop back at the beginning of July, my sons who were helping reported seeing a piece depart from one of the bolts. You can clearly see that 1/3 of a roll pin broke off. It also is clear that the alignment is off and the pin is squished. I can't get safety wire through the remaining hole.

I'm going to push for new bolts all around or at least complete roll pin replacement.
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Claude Pitre
RV-9A #91081, C-GCPT
Dynon SkyView HDX, IO-320 and WW 200RV C/S. Flying as of August 6, 2018

Added GPS 175 and authorized for IFR April 1, 2021

Interactive map of all of my flights here
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  #40  
Old 09-25-2022, 02:13 PM
lr172 lr172 is offline
 
Join Date: Oct 2013
Location: Schaumburg, IL
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Quote:
Originally Posted by Flying Canuck View Post
I'm still fighting with this, I talked to the specialist at Whirlwind on Friday and he told me that they didn't touch the roll pins - even though their website lists their replacement at the top of the list of items done during the tear down. I'll be talking to him again tomorrow when he returns to the shop, he was out last week. I'm hoping they'll agree to working with a prop shop here in Alberta to get this fixed.

I'm attaching one more picture that turned out really sharp. When I was removing the prop back at the beginning of July, my sons who were helping reported seeing a piece depart from one of the bolts. You can clearly see that 1/3 of a roll pin broke off. It also is clear that the alignment is off and the pin is squished. I can't get safety wire through the remaining hole.

I'm going to push for new bolts all around or at least complete roll pin replacement.
You can see where it sheared almost half the pin away during tightening, ironically right at the split. Given that doesn't happen to most, I speculate ti could be due to over torquing or possible a defect in the pin metallurgy. I suggest a crows foot and proper torque adaptation to ensure they are not over tightened next time. Not sure I trust the 90* torque wrench logic. I was always taught to use a calculation based upon the leverage arm length. I stand by the suggestion to not have the split directly facing where the nut is trying to shear it off during tightening. Don't have the Mechanical Engineering degree to back that up, but it makes sense that a solid tube wall is stronger than one that is split in half. Page 8 of this application guide for roll pins used in shear clearly provides that same guidance:

https://www.spirol.com/assets/files/...n-guide-us.pdf

Kind of a shame that a prop manufacturer doesn't know this.

Also important to observe torque recommendation in the manual. Some are given for dry installation and some for use of oil or lube though not sure that would change the force that the roll pin sees.

Larry
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Last edited by lr172 : 09-25-2022 at 02:35 PM.
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