Today's Message Index:
----------------------
1. 04:54 AM - CJ6 baggage compartment (Harv)
2. 06:41 PM - CJ Magneto Probs (mnorman)
3. 07:07 PM - Re: Prop hub stud torque (Dale)
4. 07:08 PM - Re: CJ Magneto Probs (Warren Hill)
5. 07:10 PM - Re: CJ Magneto Probs (KingCJ6@aol.com)
6. 07:21 PM - Barrett M-14pf (Dale)
7. 08:05 PM - Re: CJ Magneto Probs (Bill Geipel)
8. 08:37 PM - Re: CJ Magneto Probs (mnorman)
9. 09:12 PM - Re: CJ Magneto Probs (Roger Kemp)
10. 09:52 PM - Re: Prop hub stud torque (Walter Lannon)
Message 1
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| Subject: | CJ6 baggage compartment |
Hi
I'm trying to have a baggage box built in my CJ6 behind the rear cockpit seat doors.
Does anyone have specific details and drawing including stress/structural notes
on materials/bolt to use etc. A working drawing would be most appreciated.
I would think someone must have looked at this in some detail, after all if you
have made this mod you would want to be sure its capable of holding up when subjected
to +6/-3 g.
Any help appreciated.
Rgs
Harv
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=339540#339540
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| Subject: | CJ Magneto Probs |
Hi All,
Hoping someone might know what this problem is.
I've been having some work done on my Nanchang so its been fiddled with a fair
bit. It started and ran fine, turned the mags off and it kept running!
Any ideas/advice on what it could be?
Thanks
Mark
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=339629#339629
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| Subject: | Re: Prop hub stud torque |
Torque: MT Propellers only Not V-530
MTV-9 Propeller on M-14PF uses a SAE-2 hub with 1/2 in bolts.
3/8" 24 UNF bolts 25 - 27 ftlb
7/16" 20 UNF bolts 41 - 44 ftlb
7/16" 20 UNF stopnuts 33 - 35 ftlb
7/16" 20 UNF stopnuts:
A-flange on Centurion 2.0 mit 155 HP 40 - 42 ftlb
1/2" 20 UNF bolts (< 300 HP) 63 - 66 ftlb
1/2" 20 UNF bolts (> 300 HP) 90 - 100 ftlb
and SMA SR 305-230
1/2" 20 UNF stopnuts (< 300 HP) 63 - 66 ftlb
1/2" 20 UNF stopnuts (> 300 HP) 80 - 85 ftlb
9/16" 18 UNF stopnuts 100 - 110 ftlb
Note: Torque values are valid for dry, free-moving threads
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http://forums.matronics.com/viewtopic.php?p=339632#339632
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| Subject: | Re: CJ Magneto Probs |
Mark,
One, or both of the magneto P-leads may be disconnected, or the wire(s) broken.
Warren
On May 11, 2011, at 6:38 PM, mnorman wrote:
>
> Hi All,
>
> Hoping someone might know what this problem is.
>
> I've been having some work done on my Nanchang so its been fiddled with a fair
bit. It started and ran fine, turned the mags off and it kept running!
>
> Any ideas/advice on what it could be?
>
> Thanks
>
> Mark
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=339629#339629
>
>
>
>
>
>
>
>
>
>
Message 5
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| Subject: | Re: CJ Magneto Probs |
"P" lead broken or not grounded. Your A&P didn't notice this?
In a message dated 5/11/2011 6:41:46 P.M. Pacific Daylight Time,
mark@albanyproperty.com.au writes:
--> Yak-List message posted by: "mnorman" <mark@albanyproperty.com.au>
Hi All,
Hoping someone might know what this problem is.
I've been having some work done on my Nanchang so its been fiddled with a
fair bit. It started and ran fine, turned the mags off and it kept running!
Any ideas/advice on what it could be?
Thanks
Mark
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=339629#339629
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Just something to look at.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=339635#339635
Attachments:
http://forums.matronics.com//files/cimg0163_149.jpg
Message 7
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| Subject: | Re: CJ Magneto Probs |
Ground wire.
Blue Sky's
On May 11, 2011, at 7:38 PM, "mnorman" <mark@albanyproperty.com.au> wrote:
>
> Hi All,
>
> Hoping someone might know what this problem is.
>
> I've been having some work done on my Nanchang so its been fiddled with a fair
bit. It started and ran fine, turned the mags off and it kept running!
>
> Any ideas/advice on what it could be?
>
> Thanks
>
> Mark
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=339629#339629
>
>
>
>
>
>
>
>
>
>
Message 8
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| Subject: | Re: CJ Magneto Probs |
Thanks for the replies,
We just wheeled it outside for an engine run the other day and haven't got back
to it yet. I thought someone here would probably know what it was and save us
some time.
Thanks again
Mark
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=339640#339640
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| Subject: | Re: CJ Magneto Probs |
Check your P lead connections.
Doc
-----Original Message-----
>From: Bill Geipel <czech6@mesanetworks.net>
>Sent: May 11, 2011 9:57 PM
>To: "yak-list@matronics.com" <yak-list@matronics.com>
>Subject: Re: Yak-List: CJ Magneto Probs
>
>
>Ground wire.
>
>blue Sky's
>
>
>On May 11, 2011, at 7:38 PM, "mnorman" <mark@albanyproperty.com.au> wrote:
>
>>
>> Hi All,
>>
>> Hoping someone might know what this problem is.
>>
>> I've been having some work done on my Nanchang so its been fiddled with a fair
bit. It started and ran fine, turned the mags off and it kept running!
>>
>> Any ideas/advice on what it could be?
>>
>> Thanks
>>
>> Mark
>>
>>
>>
>>
>> Read this topic online here:
>>
>> http://forums.matronics.com/viewtopic.php?p=339629#339629
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
Message 10
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| Subject: | Re: Prop hub stud torque |
Where to begin?
There appears to be a need for some understanding of what "torque" is all
about and I guess I will bore everyone to tears. My apology in advance!
1. The prop. attach studs on the M14P are designed to carry tensile loads
only. There is of course a very high shear component but this is reacted
solely by the mating hub and flange serrations. The proper mating of the
serrations depends on the tensile load of the studs but does not transfer
shear loading to the studs.
A shaft mounted propellor reacts shear loads directly and independently
through the shaft SPLINES.
2. The waisted (not wasted) part of the stud (usually referred to as a
necked stud) is done for a specific reason.
A stud, or bolt, designed to carry tension loads must be STRETCHED to a
tensile loading in excess of the loads expected to be encountered in
service. This is particularly critical for a joint subject to cyclic
loading and unloading.
Of course the stretching must not exceed the elastic limit
of the fastener.
If not pre-stretched the fastener will be repeatedly stretched in service.
Depending on the frequency and magnitude of this action the stud, or the
structure it holds, will eventually fail due to fatigue.
If it is correctly stretched, within its elastic limit, it will never
stretch in normal service and will not fail due to fatigue.
A necked stud has the diameter reduced to correspond with the thread root
diameter so that this stretching is reasonably uniform throughout the length
and does not focus the entire load in the thread root area. In addition,
highly loaded fasteners like this will have rolled threads.
In any event a fastener loaded in tension is stretched on the basis of the
weakest part - usually the thread root dia.
A fastener loaded in shear, which implies a close tolerance fit, is graded
on the shear strength of the full dia. shank.
3. The Prop retaining studs and the blade clamping bolts have many
similarities, they are necked and they both appear to have rolled threads
but they are very different in size.
The blade bolt is 10 mm compared to the stud which is 14 mm. That is the
nominal dimension, NOT the necked area.
The 10 mm bolt is carrying pure tension loads without cyclic loading and is
torqued to 8 Kgm, 78NM or 58 lb/ft. The limit is 57 to 63 lb/ft.
The 14 mm stud has approximately double the cross sectional area of the
bolt, is also loaded in tension WITH
a cyclic factor and it is torqued to the same number? Not a chance.
4. What is torque as it relates to a fastener? It is a simple, easy to
apply method of somewhat controlled STRETCHING of a fastener. It is highly
subject to errors due to thread condition, lubrication, etc.
It is not used in some very highly critical joints because of those
limitations. Instead a direct measurement of bolt stretch is done using a
micrometer or ultrasound techniques. The limits are given in actual bolt
stretch.
5. Torque (stretch) values are determined from the ultimate strength of the
material (UTS), the yield strength (upper elastic limit), effective cross
section area, thread pitch and the expected service loading.
.
6. I would hope someone could find a published torque value for the V530
nuts that make sense. 57 lb/ft does not.
Fasteners do fail from over tightening. There is always a limit. But more
often they fail from under tightening and subsequent fatigue.
Cheers;
Walt
----- Original Message -----
From: "Royden 2011" <heaysr@telus.net>
Sent: Tuesday, May 10, 2011 11:01 PM
Subject: Re: Yak-List: Prop hub stud torque
>
> Dear Yaklisters
>
> This is an appeal please to not rely on personal belief or equivalence to
> North American propellers/practice.
>
> The Russians built these very successful and robust V-530 props for
> decades - let's go by their manual. That they have evidently been
> seriously over-torqued (~60%) in the USA without previous reports of
> failures is a testament to their robustness.
>
> Jill's conversion is correct.
>
> 7 kg.m = 50.6 ft.lb
> 8 kg.m = 57.9 ft.lb
>
> As for stud size: - what you see in NOT what you get. The stud nut is 22
> mm and one sees only thread exposed when the prop is off the aircraft.
>
> But being on the receiving end of a broken stud one finds a stud shank
> that is wasted to a diameter noticeably less than the inside diameter of
> the thread - and always hidden from view when normally within the prop
> flange.
>
> Why the designers do that, I can only guess. Presumably because the spline
> carries all shear loads and the stud is designed to carry only tensile
> loads. By wasting the shank, it will not attract shear loads from the
> holes through which it loosely passes in the prop hub.
>
> The specified torque must be based on the wasted shank diameter (normally
> hidden from view) and not the larger thread that is normally in view.
> Hence the deceivingly low torque values specified by the Russians for
> these studs.
>
> If Jill posts all the torque numbers, you will find the specified torque
> for the prop blade c clamps is higher than the for the flange studs (59
> ft.lb if I remember well). Maybe not surprising as the shank diameter for
> the C clamp bolt visually appears larger than the wasted diameter of the
> prop flange studs. (However, to be confirmed with measurements next
> weekend).
>
> I also hope to get you some photos showing the failed stud by next
> weekend.
>
> Please take care and be vigilant with your torque wrenches!
>
> Royden
>
>
> ----- Original Message -----
> From: "Walter Lannon" <wlannon@persona.ca>
> To: <yak-list@matronics.com>
> Sent: Tuesday, May 10, 2011 7:00 PM
> Subject: Re: Yak-List: Prop hub stud torque
>
>
>>
>> Hi Jill;
>>
>> I believe Eric's 87 lb/ft for the V530 prop. retaining nuts is correct.
>> I use 82 to 93 lb/ft. Can't remember where it came from but it fits for
>> the bolt size and the engine HP. Hartzells & McCauleys on 150- 180 HP
>> require 50 ft/lb.
>> MT propellors (for over 300HP and with 9/16" studs) require 100 to 110
>> lb/ft.
>>
>> 57 lb/ft is the correct torque for the V530 and J9-G1 blade clamp nuts.
>>
>> Walt
>>
>> ----- Original Message -----
>> From: "Jill Gernetzke" <jill@m-14p.com>
>> To: <yak-list@matronics.com>
>> Sent: Tuesday, May 10, 2011 7:03 AM
>> Subject: Yak-List: Prop hub stud torque
>>
>>
>>>
>>> Just saw this post and thought I should correct some bad information.
>>> The
>>> torque value specified in the Russian V-530 Overhaul manual (Dated 14
>>> May
>>> 1975) for the six prop hub studs is 7 (+1) kgc-m. (50 - 57 ft/lbs - if
>>> Online Conversion is correct.) This is significantly different than 87.
>>>
>>> I have never heard of a stud breaking on a V-530 hub, but I have now.
>>>
>>> Jill
>>> M-14P, Inc.
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>>
>>
>>
>
>
>
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