X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail.lincsatmail.com ([207.179.143.254] verified) by logan.com (CommuniGate Pro SMTP 5.0.8) with ESMTP id 971806 for flyrotary@lancaironline.net; Mon, 06 Feb 2006 02:22:43 -0500 Received-SPF: neutral receiver=logan.com; client-ip=207.179.143.254; envelope-from=echolakeresort@telus.net Received: from echolake-cc8a26 ([204.101.233.153]) (authenticated bits=0) by mail.lincsatmail.com (8.12.10/8.12.10) with ESMTP id k167LeZj002907 for ; Mon, 6 Feb 2006 03:21:46 -0400 MIME-Version: 1.0 Message-Id: <43E6F8D9.000004.04032@ECHOLAKE-CC8A26> Date: Sun, 5 Feb 2006 23:20:57 -0800 (Pacific Standard Time) Content-Type: Multipart/Alternative; boundary="------------Boundary-00=_XE89BHK0000000000000" X-Mailer: IncrediMail (4502089) From: "Echo Lake Fishing Resort (Georges Boucher)" References: To: "Rotary motors in aircraft" Subject: Re: [FlyRotary] Re: Torque and torque sequence X-FID: FLAVOR00-NONE-0000-0000-000000000000 X-Priority: 3 --------------Boundary-00=_XE89BHK0000000000000 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Thomas=0D Manufacturer that specify stretch torque usually have a protractor adapte= r that fits between the socket and the wrench as well as a pointer that indicate's the number of degrees that the bolt or nut as travelled. ( the= y give you the number of degrees) as well you start with a basic torque wre= nch torque, usually around 15 ft lbs for head bolts.=0D I have done the same without degree specs, it's accuracy may be arbitrary but it comes close. I run a pap (tread chaser) through to make sure the threads are clean and a dye on the bolt to do same, I lightly oil the threads and the torque area on the bolt head, tighten to 15 ft lbs. Make= a mark on the torqued surface that lines up with a point on the head of the bolt, mark a line from the center of the bolt head , through the point to the mark on the torqued surface, that becomes you '0' mark, torque the bo= lt to the specified torque + about 3lbs ( on a 50ft lb spec.) repeat the lin= e through the existing mark on the head bolt, project it on the torqued surface & measure the angle with a protractor. I did this 3 times on different heads and torque , the results came out within a degree.=0D =0D Do the thread cleaning on all the bolts & holes, us a light oil for lub. The the benefit other the torque wench method is that you will get an eve= n STRECH on the bolts and you will not find loose bolts after heating & cooling cycles,=0D I know this will sound odd the you engineers out there but it works for m= e!=0D =0D Georges B.=0D -------Original Message-------=0D =0D From: rijakits=0D Date: 02/05/06 18:14:12=0D To: Rotary motors in aircraft=0D Subject: [FlyRotary] Re: Torque and torque sequence=0D =0D Hi George,=0D =0D Question: Is there any chart/rule of thumb/etc. how to convert a torque-value into a rotation-degree value?=0D Rotation degree should be way more accurate than a regular torque-wrench.= =2E. it's just not as simple as setting the value and listen for the click.=0D =0D I dealt with 3 different ways to "torque" bolts/nuts ( except the usual torque-wrench way)=0D =0D a) Ships diesel engine (8000hp, 7 cylinders), changing pistons:=0D Headboltnuts are tightened fingertight (no hex on the nut, just 1/4 holes radially to move the nut with a 6" long 1/4 rod - nut thread about 2" diameter, nut diameter about 5-6")=0D Then there is another nut on top of the lower one, which is engaged with = a hydraulic ram, which will strech the stud. Then fingertight nut was=20 tightened" about 1-1/4 turn (or so - according to the manual) - hydraulic= s off and the devil wouldn't be able to move the nut...=0D =0D b) Ships diesel engine: In this case the Headbolts/studs are hollow:=0D Head gets torqued down a relative low value, just to make sure it is seat= ed right and then the nuts are backed off again. Then heating elements, some= 1 5 meters long are getting inserted and heated up to somewhere around 240 = =BAC (not enough to cause any metallurgic changes). Then fingertight the same style nut as above (watch your fingers, it is hot!). remove the heaters - set. Call the devil again....=0D (Even if one forgot to back up the nuts they would come completely loose while the heat was on)=0D =0D =0D c) Rotorhead bolt and coning hinge bolts on Robinson Helicopters:=0D Measure the length of the bolts with a dial indicator (mounted to holding fixture), torque the nut in increments and check with the dial indicator often. About a 3/4 " bolt - stretch 0.021-0.022" ( I think....). Best is = to lift the rotor blades to unload any shear from the bolt, otherwise it get= s pretty hard to stretch....=0D =0D I guess on the Rotary it is not necessary and/or practical to measure bolt-stretch, however there are fairly affordable "Rotation-degree" - wrenches out there. Just never came across any instructions that called f= or it.=0D =0D One itchy issue with regular torque wrenches is, wether a given torque is= =20 dry" or "wet" (lubricated).=0D What is dry? Just clean or "electrocleaner"-clean?=0D If you need/want to grease the nut/bolt how much do you have to reduce th= e torque? (There are values and lists in about every GA-maintenance manual, but how transferable are these values to the nonaviation materials in the Rotary?)=0D Also, how often do you have your wrench checked - you won't believe how m= uch accuracy "bleeds" in a year....=0D =0D Someone mentioned his "calibrated" arm - big no-no!! Whatever "feels" lik= e a certain torque to you any given day will be off value!! Again what you fe= el in your arm may very well be the same "feel"-value, but how much force yo= u actually apply is in the stars (.... and depends completely on your energylevel/physical state/psychological state/mood of the moment!!) - =0D Never replace the torque-wrench with your arm! Specially with smaller bol= ts and nuts!!=0D (Test yourself: "Feel up" some weight in a bucket covered with a towell, have someone add/subtract weight and feel it up again - note the numbers. Then run, weightlift, exhaust yourself and repeat the exercise - you will= be surprised how much off your "feel" is!! It is something similar with spee= d perception: size, sound, distance will throw you off completely!!=0D =0D =0D FWIW,=0D =0D Thomas Jakits=0D ----- Original Message ----- =0D From: Echo Lake Fishing Resort (Georges Boucher) =0D To: Rotary motors in aircraft =0D Sent: Sunday, February 05, 2006 12:37 PM=0D Subject: [FlyRotary] Re: Torque and torque sequence=0D =0D =0D FWIW backing off each bolt as you re-torque gives you a more accurate torque. Final torque is much more accurate when using the torque by rotation degree (bolt stretch). (never had to re-torque anything using t= he stretch system)=0D Georges B.=0D =0D -------Original Message-------=0D =0D From: rijakits=0D Date: 02/05/06 09:19:12=0D To: Rotary motors in aircraft=0D Subject: [FlyRotary] Re: Torque and torque sequence=0D =0D =0D ----- Original Message ----- =0D From: Al Gietzen =0D To: Rotary motors in aircraft =0D Sent: Sunday, February 05, 2006 11:32 AM=0D Subject: [FlyRotary] Torque and torque sequence=0D =0D =0D ----- Original Message ----- =0D From: Lehanover@aol.com =0D To: Rotary motors in aircraft =0D Sent: Saturday, February 04, 2006 6:28 PM=0D Subject: [FlyRotary] Re: Atkins errors=0D =0D In a message dated 2/4/2006 5:56:30 PM Eastern Standard Time, ALVentures@= cox net writes:=0D A couple of questions: Why are two of the bolts larger? What is the torq= ue spec on these bolts for the 20B? I seem to recall 26-28 ft-lbs. I can=92= t get a torque wrench on the bolts without removing the re-drive, engine mo= unt and flywheel, but I have a pretty well calibrated arm.=0D =0D Al=0D When you add torque to those bolts, the bolts closest to them will go und= er torque.=0D =0D So go through the whole torque sequence several times if at all possible. This has been the case on every engine I have built.=0D =0D Lynn E. Hanover=0D =0D =0D =0D I don't havea Mazda Manual, but generally in a case like this there are 2 ways to tighten the bolts correctly:=0D =0D a) Tighten 2 opposite bolts until seated - then torque each to spec. All other bolts are tigthtened spreading out from the 2 torqued: =0D e.g. Torque the 2 big bolts then: 1st bolt to left of one big b. - 1st bo= lt to the left of the other big b. - 1st bolt to the right of the one big b.= - 1st bolt to the right of the other big b. - 2nd bolt to the left...... yo= u get the idea.=0D =0D This way you have the pieces flat together on a "centerline" and "lay" th= e rest down on each side of this centerline - spreading it out so that no=20 wrinkles" are created....=0D =0D b) A stepped sequence is shown in a manual: mostly in cross pattern and something like 10 lb/18lb/26lb=0D =0D =0D Thomas;=0D I understand the niceties of torque sequence; but it would seem that is a= ll out the window when the engine has been run about 6 hours, many cycles to full power, and a dozen or more temperature cycles to 200-210 F; all with the two large bolts loose. As far as I know nothing untoward has happene= d, but how can I be sure?=0D =0D Al=0D =0D Al, =0D didn't intend to step on your engineering prowess, you are waaaay ahead o= f me in that department! =0D Just was pointing out what (little) I remember from Engineering school.=0D In your case, the only acceptable (...for me) way to go is, to remove the redrive, loosen all bolts and tighten them according to the manual.=0D In a (race)car you might get away with an "emergency"-thighten-up, but it= is your a** up in the air!!=0D Your engine was running well for a while now, so a complete tear-down see= ms excessive, but I believe wrong ( or none ...) torque-settings will show their ugly face in the long run. Better make sure everything is right and tight. =0D I understand that it is definitely NOT your fault, but your engine builde= rs - you might believe these guys put a little more extra care into assembli= ng an AC engine - manual on the job, step by step list to hook off items, after-assembly check list, etc.=0D =0D In your case torques on bolts don't mean anything at this time. "Niceties= of torque sequence" applies IF DONE (right) - obviously on your engine no on= e cared enough to check torque, let alone sequence.=0D Doesn't shine to well on a supposedly reputable shop....=0D =0D Enough ranting, back lurking!=0D =0D Thomas J.=0D =0D =0D =0D =0D =0D =0D =20 --------------Boundary-00=_XE89BHK0000000000000 Content-Type: Text/HTML; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Thomas
Manufacturer that specify stretch torque usually have a pr= otractor adapter that fits between the socket and the  wrench as wel= l as a pointer that indicate's the number of degrees that the bolt or nut= as travelled. ( they give you the number of degrees) as well you start w= ith a basic torque wrench torque, usually around 15 ft lbs for head bolts= =2E
I have done the same without degree specs, it's accuracy may be arbi= trary but it comes close. I run a pap (tread chaser) through to make sure= the threads are clean and a dye on the bolt to do same, I lightly oil th= e threads  and the torque area on the bolt head, tighten to 15 ft lb= s. Make a mark on the torqued surface that lines up with a point on the h= ead of the bolt, mark a line from the center of the bolt head , through t= he point to the mark on the torqued surface, that becomes you '0' mark, t= orque the bolt to the specified torque + about 3lbs ( on a 50ft lb spec.)= repeat the line through the existing mark on the head bolt, project it o= n the torqued surface & measure the angle  with a protractor. I = did this 3 times on different heads and torque , the results came out wit= hin a degree.
 
 Do the thread cleaning on all the bolts & holes, us a ligh= t oil for lub. The the benefit other the torque wench method is that you = will get an even STRECH on the bolts and you will not find loose bolts af= ter  heating & cooling cycles,
I know this will sound odd the you engineers out there but it works = for me!
 
Georges B.
-------Original Message-------
 
From: rijakits
Date: 02/05/06 18:= 14:12
Subject: [FlyRotar= y] Re: Torque and torque sequence
 
Hi George,
 
Question: Is there any chart/rule of thumb/etc. how to convert = a torque-value into a rotation-degree value?
Rotation degree should be way more accurate than a regular torque-wr= ench....it's just not as simple as setting the value and listen for the c= lick.
 
I dealt with 3 different ways to "torque" bolts/nuts ( except the us= ual torque-wrench way)
 
a) Ships diesel engine (8000hp, 7 cylinders), changing pistons:
Headboltnuts are tightened fingertight (no hex on the nut, just 1/4 = holes radially to move the nut with a 6" long 1/4 rod - nut thr= ead about 2" diameter, nut diameter about 5-6")
Then there is another nut on top of the lower one, which is engaged = with a hydraulic ram, which will strech the stud. Then fingertight nut wa= s "tightened" about 1-1/4 turn (or so - according to the manual) - hydrau= lics off and the devil wouldn't be able to move the nut...
 
b) Ships diesel engine: In this case the Headbolts/studs are hollow:=
Head gets torqued down a relative low value, just to make sure = it is seated right and then the nuts are backed off again. Then heating e= lements, some 1.5 meters long are getting inserted and heated up to somew= here around 240 =BAC (not enough to cause any metallurgic changes). Then = fingertight the same style nut as above (watch your fingers, it is hot!).= remove the heaters - set. Call the devil again....
(Even if one forgot to back up the nuts they would come completely l= oose while the heat was on)
 
 
c) Rotorhead bolt and coning hinge bolts on Robinson Helicopters:
Measure the length of the bolts with a dial indicator (mounted to ho= lding fixture), torque the nut in increments and check with the dial indi= cator often. About a 3/4 " bolt - stretch 0.021-0.022" ( I think....). Be= st is to lift the rotor blades to unload any shear from the bolt, otherwi= se it gets pretty hard to stretch....
 
I guess on the Rotary it is not necessary and/or practical to measur= e bolt-stretch, however there are fairly affordable "Rotation-degree" - w= renches out there. Just never came across any instructions that called fo= r it.
 
One itchy issue with regular torque wrenches is, wether a given torq= ue is "dry" or "wet" (lubricated).
What is dry? Just clean or "electrocleaner"-clean?
If you need/want to grease the nut/bolt how much do you have to redu= ce the torque? (There are values and lists in about every GA-maintenance = manual, but how transferable are these values to the nonaviation material= s in the Rotary?)
Also, how often do you have your wrench checked - you won't believe = how much accuracy "bleeds" in a year....
 
Someone mentioned his "calibrated" arm - big no-no!! Whatever "feels= " like a certain torque to you any given day will be off value!! Again wh= at you feel in your arm may very well be the same "feel"-value, but how m= uch force you actually apply is in the stars (.... and depends completely= on your energylevel/physical state/psychological state/mood of the = moment!!) -
Never replace the torque-wrench with your arm!= Specially with smaller bolts and nuts!!
(Test yourself: "Feel up" some weight in a bucket covered with a tow= ell, have someone add/subtract weight and feel it up again - note the num= bers. Then run, weightlift, exhaust yourself and repeat the exercise - yo= u will be surprised how much off your "feel" is!! It is something si= milar with speed perception: size, sound, distance will throw you off com= pletely!!
 
 
FWIW,
 
Thomas Jakits
----- Original Message -----
Sent: Sunday, February 05, 2006 12= :37 PM
Subject: [FlyRotary] Re: Torque an= d torque sequence

 FWIW backing off each bolt as you re-torque gives you a more a= ccurate torque. Final torque is much more accurate when using  the t= orque by rotation  degree (bolt stretch). (never had to re-torque an= ything using the stretch system)
Georges B.
 
-------Original Message-------
 
From: rijakits
Date: 02/05/06 09:= 19:12
Subject: [FlyRotar= y] Re: Torque and torque sequence
 
 
----- Original Message -----
<= B>From: Al Gietzen
Sent: Sunday, February 05, 2006 11= :32 AM
Subject: [FlyRotary] Torque and to= rque sequence

----- Original Message -----

Sent: Saturday, February 04, 2006 6:28 PM

Subject: [FlyRotary] Re: Atkins errors=

 

In a message dated <= FONT face=3DArial color=3Dblack size=3D2>2/4/2006 5:56:= 30 PM Eastern Standard Tim= e, ALVentures@cox.net writes:

A couple of questions: Why are two of the bolts l= arger?  What is the torque spec on these bolts for the 20B?  I = seem to recall 26-28 ft-lbs.  I can=92t get a torque wrench on the b= olts without removing the re-drive, engine mount and flywheel, but I have= a pretty well calibrated arm.

 

Al

When you add torque to those bolts, the bolts closest= to them will go under torque.

 

So go through the whole torque sequence several times= if at all possible. This has been the case on every engine I have built.=

 

Lynn E. Hanover

 

 

 

I don't havea Mazda Manual, but generally = in a case like this there are 2 ways to tighten the bolts correctly:

 

a) Tighten 2 opposite bolts until seated - then torqu= e each to spec. All other bolts are tigthtened spreading out from the 2 t= orqued:

e.g. Torque the 2 big bolts then: 1st bolt to left of= one big b. - 1st bolt to the left of the other big b. - 1st bo= lt to the right of the one big b. - 1st bolt to the right of th= e other big b. - 2nd bolt to the left...... you get the idea.

 

This way you have the pieces flat together on a "cent= erline" and "lay" the rest down on each side of this centerline - spreadi= ng it out so that no "wrinkles" are created....

 

b) A stepped sequence is shown in a manual: mostly in= cross pattern and something like 10 lb/18lb/26lb

 

 

Thomas;

I understand th= e niceties of torque sequence; but it would seem that is all out the wind= ow when the engine has been run about 6 hours, many cycles to full power,= and a dozen or more temperature cycles to 200-210 F; all with the two la= rge bolts loose.  As far as I know nothing untoward has happened, bu= t how can I be sure?

&= nbsp;

Al

&= nbsp;

Al,

didn't intend to step on your engineering prowess, you are waaaay = ahead of me in that department!

Just was pointing out what (little) I remember from Engineering sc= hool.

In your case, the only acceptable (...for me) way to go is, to rem= ove the redrive, loosen all bolts and tighten them according to the manua= l.

In a (race)car you might get away with an "emergency"-thighten-up,= but it is your a**  up in the air!!

Your engine was running well for a while now, so a complete tear-d= own seems excessive, but I believe wrong ( or none ...) torque-settings w= ill show their ugly face in the long run. Better make sure everything is = right and tight.

I understand that it is definitely NOT your fault, but your engine= builders - you might believe these guys put a little more extra care int= o assembling an AC engine - manual on the job, step by step list to hook = off items, after-assembly check list, etc.

 

In your case torques on bolts don't mean anything at this time. "N= iceties of torque sequence" applies IF DONE (right) - obviously on your e= ngine no one cared enough to check torque, let alone sequence.

Doesn't shine to well on a supposedly reputable shop....

 

Enough ranting, back lurking!

 

Thomas J.

&= nbsp;

 

 
 
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