Eagler's Nest

Engines => 2 Cylinder => 1/2 vw => Topic started by: Bob Wood on December 06, 2013, 09:27:49 AM

Title: Prop bolts on 1/2VW LE XL
Post by: Bob Wood on December 06, 2013, 09:27:49 AM

I am going to run a TN prop on a Mosler prop hub and have old Mosler documentation on the bolt set up, they recommended a castle nut and pins. Due to the fact that torque always has to be checked with the wooden props we run I am thinking a locking castle nut would be the best. Just slip out the pin and re torque and re pin. I do not recall seeing props using this set up, seems like most use lock nuts and washers...
I can't imaging using a non locking castle nut.....

What are you guys running?

Thanks,
Bob

Title: Re: Prop bolts on 1/2VW LE XL
Post by: Tom H on December 07, 2013, 06:08:15 AM

I use AN bolts w/ castle nuts and cotter pins.

Tom H
Stubby
Treehugger

Title: Re: Prop bolts on 1/2VW LE XL
Post by: rockiedog2 on December 07, 2013, 05:58:52 PM

AN bolts with fiber loks solve all the probs of trying to torque to the little slots.
been using those for near 50 years now. has worked well for me...

Title: Re: Prop bolts on 1/2VW LE XL
Post by: Steve on December 07, 2013, 06:51:31 PM

Most of the UL's I see out here are with the fiber lock - the trick is to remember to check the torque when the seasons or regions change... When re-torquing be sure to check that the bolt grip length does not allow the nut to bottom out on the bolt shank... I've seen 3 washers under the nuts and 2 under the bolt head to get the grip length right... No more than 3 washers under the nut though...

Title: Re: Prop bolts on 1/2VW LE XL
Post by: Steve on December 30, 2013, 09:56:05 AM

This prop bolt retention system might interest those who have a concern about temperature & humidity changes effecting the prop lash-up...

Belleville Washer retention system (http://cozybuilders.org/Prop_Bolt_Bellville_Washer/)

Title: Re: Prop bolts on 1/2VW LE XL
Post by: Sparrow on January 16, 2014, 12:22:07 AM

Hi Steve,
 
I have used Belleville washers in many applications over the years.  Using them in prop tension stabilization is an excellent move.  The system maintains a constant axial load even when the axial linear length is changing, within reasonable distances.  The small changes due to the leaching and absorption of water and the changes due to temperature variation would certainly be automatically compensated for by the Belleville setup.
 
Are you currently using this particular prop attachment scheme?
 
John

Title: Re: Prop bolts on 1/2VW LE XL
Post by: Steve on January 16, 2014, 09:10:00 AM

Quote from: Sparrow on January 16, 2014, 12:22:07 AM

Hi Steve,
 
I have used Belleville washers in many applications over the years.  Using them in prop tension stabilization is an excellent move.  The system maintains a constant axial load even when the axial linear length is changing, within reasonable distances.  The small changes due to the leaching and absorption of water and the changes due to temperature variation would certainly be automatically compensated for by the Belleville setup.
 
Are you currently using this particular prop attachment scheme?
 
John

John: I have a 35 hp motor and a 4" bolt pattern extension located in a dry climate... I haven't seen any change in the bolt tension... However, a builder/flyer recently upgraded to a 45 hp motor that has the 3 1/8" bolt pattern extension and operates in an area that has humidity swings... He experienced a prop loss and made a safe landing... The prop was never recovered though a lot of effort was made to do that so it leaves us looking at options... The Belleville washer stack is an elegant solution that has an engineering based development... The Belleville system is deployed successfully in the Canard community where there  is a significant history of prop tosses... Steve

Title: Re: Prop bolts on 1/2VW LE XL
Post by: Sparrow on January 16, 2014, 03:58:03 PM

Hi Steve,
 
A catastrophic prop attach failure has to be an un-nerving experience.  I enjoyed the pdf report you linked us to where he explained the sequence of events and especially the glide ratio and calculating the dead stick range and search for the closest airport.  Those Rutan craft have a great glide ratio and wonderful cruse speed. If I could get my medical I would be out there hitting the air with the wife but that day is gone forever.
 
Something of concern is where is a good place to get a crankshaft cut and balanced now that Eddie at Scat has just emailed me and told me they don’t do the 2 cyl. Engine scene any more? Does the group have any thoughts?
 
Thanks again for all the great posts and information. 
 
Right now my son wants me to teach him how to weld and build aircraft and fly.  I want to do the same.
 
Cheers to all,
 
John

Title: Re: Prop bolts on 1/2VW LE XL
Post by: Steve on January 16, 2014, 04:46:42 PM

Quote from: Sparrow on January 16, 2014, 03:58:03 PM

Hi Steve,
 
Something of concern is where is a good place to get a crankshaft cut and balanced now that Eddie at Scat has just emailed me and told me they don’t do the 2 cyl. Engine scene any more? Does the group have any thoughts?
 
Thanks again for all the great posts and information.  
 
Right now my son wants me to teach him how to weld and build aircraft and fly.  I want to do the same.
 
Cheers to all,
 
John

John:
Go to the Forum Toolbar and click [Search] put this argument in the search slot without the double quotes "V1 V2 V3" and hit the search button on the screen lower / right... You will pull an on-subject Reply to a Conversion Plans Vendor question...
Steve

Title: Re: Prop bolts on 1/2VW LE XL
Post by: Sparrow on January 16, 2014, 07:01:03 PM

TKS Steve