Today's Message Index:
----------------------
1. 04:57 AM - Phlorida Phyer clarification (Cpayne)
2. 12:42 PM - YAK55m Wing attachment bolts. (steve geard)
3. 02:58 PM - Re: YAK55m Wing attachment bolts. (A. Dennis Savarese)
4. 10:43 PM - Re: YAK55m Wing attachment bolts. (Walter Lannon)
Message 1
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| Subject: | Phlorida Phyer clarification |
Of course I'm sorry about the Californian slight...I should have realized that
in hard economic times, the average California RPA guy can't afford BOTH a wine
sommelier AND a hanger valet. Here in Phlorida, the observant pilot will notice
that our airports are co-located with either a nearby ABC Liquor or drive-thru
Beverage Castle. Summer flying is the reason. Having lived in both California
and Florida, I can describe our summers in SoCal-speak: Brutal, Dude.
Have not laughed so hard lately as I did when I went to the bumwine.com site. Thanks,
Dennis. BTW, after living in Napa/Sonoma wine country I acquired a taste
for fine wines...yep, Fairbanks Port is my spirit of choice, 17.5% of Happy
Hour, any place, any time.
On a less serious note, the exhaust heat muffs works well for the pilot but the
GIB turns blue. I have not tried the quartz heater but it makes sense in the
rear cockpit.
Craig Payne
Message 2
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| Subject: | YAK55m Wing attachment bolts. |
Hey all Steve from NZ here. YAK55m # 920402.=0AI've got a quick question ab
out the Wing attachment bolts.=0AAre they finger tight, or are they suppose
d to be shimmed and torqued up?=0AAnd has anyone come across any attachment
cracking or other defects?=0AMy birds got 360hrs on it and has a bit of pl
ay in the main Starboard attachments, the bolts are not torqued. So my gues
s is the fix would be ream the holes and fit oversize bolts???=0ACheers Ste
ve :-)=0A-=0ALifes short fly Aerobatics!!!=0A
Message 3
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| 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
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:
> 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!!!
>
> *
>
> *
Message 4
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| 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 =9Ctorque=9D 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
=9Ctorque=99' 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=99s 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=9D thread to a 1=9D 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 =98bullet=9D to avoid any wear or damage. If
you don=99t 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
Sent: Tuesday, December 10, 2013 2:57 PM
Subject: Re: Yak-List: 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
A. Dennis Savarese
334-285-6263
334-546-8182 (mobile)
www.yak-52.com
Skype - Yakguy1On 12/10/2013 2:41 PM, steve geard wrote:
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!!!
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