 |
Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
|
| View previous topic :: View next topic |
| Author |
Message |
Steve Geard
Joined: 09 Dec 2013
Posts: 36
|
|
| Back to top |
|
 |
dsavarese0812(at)bellsout
Guest
|
 Posted: Tue Dec 10, 2013 2:58 pm Post subject: YAK55m Wing attachment bolts. |
 |
|
Steve,
This is a common problem with the 55's. You are correct about the fix. The holes need to be reamed and new, oversized bolts installed. The nut should be tightened and then torqued to the point where one notch in the castellated nut aligns with the cotter pin hole in the bolt. The bolts are stressed in sheer, not in tension. Thus, most likely no torque spec on the nut.
Dennis
| Quote: | A. Dennis Savarese
334-285-6263
334-546-8182 (mobile)
www.yak-52.com
Skype - Yakguy1 |
On 12/10/2013 2:41 PM, steve geard wrote:
[quote] Hey all Steve from NZ here. YAK55m # 920402.
I've got a quick question about the Wing attachment bolts.
Are they finger tight, or are they supposed to be shimmed and torqued up?
And has anyone come across any attachment cracking or other defects?
My birds got 360hrs on it and has a bit of play in the main Starboard attachments, the bolts are not torqued. So my guess is the fix would be ream the holes and fit oversize bolts???
Cheers Steve 
Lifes short fly Aerobatics!!!
[b]
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
| Back to top |
|
|
wlannon(at)shaw.ca
Guest
|
| Posted: Tue Dec 10, 2013 10:43 pm Post subject: YAK55m Wing attachment bolts. |
|
|
Dennis & Steve;
The information Dennis has supplied is correct but since it is a subject not generally understood by many in the aviation industry I thought it may help to expand on it a bit.
The term “torque” refers to a rotational method of measuring the amount of elongation (stretch) of a bolt as the nut is tightened. It applies to joints primarily subject to tensile loading and therefore has no true relevance to a joint that is primarily loaded in shear. In highly critical tension applications (e.g.: Some engine connecting rod bolts, some split hub propellor bolts, etc.) the “torque’' method is not accurate enough and bolt stretch is directly measured with a micrometer or using ultra-sound techniques.
For most applications the torque method is adequate. The bolt is stretched to a point within it’s elastic limit where it is pre-loaded to a value higher than it will be subject to in service. This ensures that the bolt is not subject to cyclic stretching in service leading to fatigue failure.
None of the above applies to the typical shear type wing attachment joint as used on our aircraft types. It is possible however that a relatively low value torque may be given by the manufacturer but
for a quite different reason. It will be simply to guarantee that there is no axial play (looseness) allowed that could lead to wear.
A typical shear type wing joint bolt will have a threaded section much smaller in diameter than the shear loaded area. Since there is no intent to stretch the the bolt there is no need for a full dia. thread. Maybe they would specify a torque limit so that someone would not tighten a 1/2” thread to a 1” dia. bolt limit????
Steve indicated there is some play but before getting to the reaming stage it is absolutely necessary to determine how much diametrical play exists and whether or not that is within the allowable limit. That information will be in the Technical manuals. I would make every effort to find it.
At a guess (which is worth nothing!) I would think about 0.002 to 0.003 in. (0.05 to 0.075 mm) would be the maximum allowable. The joint straps will be manufactured from a 4340 (or similar) alloy steel and will be heat treated in the area of 170,000 to 200,000 psi. Line reaming in this case is not for an amateur! In fact it may have to be a precision grinding operation.
With some luck new standard bolts may bring it back within limit if it is over.
In any case whenever removing or installing shear type wing bolts you should use a ‘bullet” to avoid any wear or damage. If you don’t have these get a machine shop to make them for you. It is simply a steel bullet shaped screw on device to line things up. Also lots of grease!
Make sure the nut is tight enough so there is no possible looseness. If you want to measure the torque check the thread size and diameter and find the applicable limit for that size in standard mild steel.
Cheers;
Walt
From: A. Dennis Savarese (dsavarese0812(at)bellsouth.net)
Sent: Tuesday, December 10, 2013 2:57 PM
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Subject: Re: YAK55m Wing attachment bolts.
Steve,
This is a common problem with the 55's. You are correct about the fix. The holes need to be reamed and new, oversized bolts installed. The nut should be tightened and then torqued to the point where one notch in the castellated nut aligns with the cotter pin hole in the bolt. The bolts are stressed in sheer, not in tension. Thus, most likely no torque spec on the nut.
Dennis
| Quote: | A. Dennis Savarese
334-285-6263
334-546-8182 (mobile)
www.yak-52.com
Skype - Yakguy1 |
On 12/10/2013 2:41 PM, steve geard wrote:
[quote] Hey all Steve from NZ here. YAK55m # 920402.
I've got a quick question about the Wing attachment bolts.
Are they finger tight, or are they supposed to be shimmed and torqued up?
And has anyone come across any attachment cracking or other defects?
My birds got 360hrs on it and has a bit of play in the main Starboard attachments, the bolts are not torqued. So my guess is the fix would be ream the holes and fit oversize bolts???
Cheers Steve
Lifes short fly Aerobatics!!!
href="http://www.aeroelectric.com">www.aeroelectric.com
href="http://www.buildersbooks.com">www.buildersbooks.com
href="http://www.homebuilthelp.com">www.homebuilthelp.com
href="http://www.mypilotstore.com">www.mypilotstore.com
href="http://www.mrrace.com">www.mrrace.com
href="http://www.matronics.com/contribution">http://www.matronics.com/chref="http://www.matronics.com/Navigator?Yak-List">http://www.matronics.com/Navigator?Yak-List
href="http://forums.matronics.com">http://forums.matronics.com
[b]
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
| Back to top |
|
|
GeorgeCoy
Joined: 02 Dec 2010
Posts: 310
|
| Posted: Wed Dec 11, 2013 7:03 am Post subject: YAK55m Wing attachment bolts. |
|
|
Steve, Contact me off list with the dimensions of your bolts. I have a collection of -52 and -55 spar bolts
George Coy
CAS Ltd.
714 Airport Rd.
Swanton VT 05488
802-868-5633 off
802-363-5782 cell
802-868-4465 Fax
george.coy(at)gmail.com (george.coy(at)gmail.com)
http://coyacft.com/
SKYPE george.coy
From: owner-yak-list-server(at)matronics.com [mailto:owner-yak-list-server(at)matronics.com] On Behalf Of Walter Lannon
Sent: Wednesday, December 11, 2013 1:43 AM
To: yak-list(at)matronics.com
Subject: Re: YAK55m Wing attachment bolts.
Dennis & Steve;
The information Dennis has supplied is correct but since it is a subject not generally understood by many in the aviation industry I thought it may help to expand on it a bit.
The term “torque” refers to a rotational method of measuring the amount of elongation (stretch) of a bolt as the nut is tightened. It applies to joints primarily subject to tensile loading and therefore has no true relevance to a joint that is primarily loaded in shear. In highly critical tension applications (e.g.: Some engine connecting rod bolts, some split hub propellor bolts, etc.) the “torque’' method is not accurate enough and bolt stretch is directly measured with a micrometer or using ultra-sound techniques.
For most applications the torque method is adequate. The bolt is stretched to a point within it’s elastic limit where it is pre-loaded to a value higher than it will be subject to in service. This ensures that the bolt is not subject to cyclic stretching in service leading to fatigue failure.
None of the above applies to the typical shear type wing attachment joint as used on our aircraft types. It is possible however that a relatively low value torque may be given by the manufacturer but
for a quite different reason. It will be simply to guarantee that there is no axial play (looseness) allowed that could lead to wear.
A typical shear type wing joint bolt will have a threaded section much smaller in diameter than the shear loaded area. Since there is no intent to stretch the the bolt there is no need for a full dia. thread. Maybe they would specify a torque limit so that someone would not tighten a 1/2” thread to a 1” dia. bolt limit????
Steve indicated there is some play but before getting to the reaming stage it is absolutely necessary to determine how much diametrical play exists and whether or not that is within the allowable limit. That information will be in the Technical manuals. I would make every effort to find it.
At a guess (which is worth nothing!) I would think about 0.002 to 0.003 in. (0.05 to 0.075 mm) would be the maximum allowable. The joint straps will be manufactured from a 4340 (or similar) alloy steel and will be heat treated in the area of 170,000 to 200,000 psi. Line reaming in this case is not for an amateur! In fact it may have to be a precision grinding operation.
With some luck new standard bolts may bring it back within limit if it is over.
In any case whenever removing or installing shear type wing bolts you should use a ‘bullet” to avoid any wear or damage. If you don’t have these get a machine shop to make them for you. It is simply a steel bullet shaped screw on device to line things up. Also lots of grease!
Make sure the nut is tight enough so there is no possible looseness. If you want to measure the torque check the thread size and diameter and find the applicable limit for that size in standard mild steel.
Cheers;
Walt
From: A. Dennis Savarese (dsavarese0812(at)bellsouth.net)
Sent: Tuesday, December 10, 2013 2:57 PM
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Subject: Re: YAK55m Wing attachment bolts.
Steve,
This is a common problem with the 55's. You are correct about the fix. The holes need to be reamed and new, oversized bolts installed. The nut should be tightened and then torqued to the point where one notch in the castellated nut aligns with the cotter pin hole in the bolt. The bolts are stressed in sheer, not in tension. Thus, most likely no torque spec on the nut.
Dennis
| Quote: | | A. Dennis Savarese334-285-6263334-546-8182 (mobile)www.yak-52.comSkype - Yakguy1 |
On 12/10/2013 2:41 PM, steve geard wrote:
| Quote: |
Hey all Steve from NZ here. YAK55m # 920402.
I've got a quick question about the Wing attachment bolts.
Are they finger tight, or are they supposed to be shimmed and torqued up?
And has anyone come across any attachment cracking or other defects?
My birds got 360hrs on it and has a bit of play in the main Starboard attachments, the bolts are not torqued. So my guess is the fix would be ream the holes and fit oversize bolts???
Cheers Steve
Lifes short fly Aerobatics!!!
|
012345
6<www.buildersbooks.comwww.homebuilthelp.comwww.mypilotstore.comwww.mrrace.com[/b][/quote]http://www.matronics=================[/b][/quote]< - MATRONICS WEB FORUMS via the Web --> http://forums.matronics.com[/url]=====[/b][b]
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
| Back to top |
|
|
Steve Geard
Joined: 09 Dec 2013
Posts: 36
|
| Posted: Fri Apr 11, 2014 2:37 am Post subject: Re: YAK55m Wing attachment bolts. |
|
|
The holes check out round and 20mm. The bolt we measured was also round and 19.92mm. We're thinking as theyre both round that maybe thats how they come from the factory, Anyone got any bolts around 19.98 ish? What is the clearance required for a slide fit?
Cheers Steve
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
_________________
SteveO |
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
