RE: [COUPERS-TECH] Tension on cables still correction

[MarWarHamp]

----[Please read http://ercoupers.com/disclaimer.htm before following any advice in this forum.]----                This may are may not be totally correct about a frozen pulley. The tension could overcome the drag of the cable over the pulley. Causing the low tension cable to come up to a closer value to the cable being tightened.   -----Original Message-----          First, this was about control cable tension on an Ercoupe. Which is a closed Loop with two free to move bellcranks and two cable with turnbuckles for adjustments for length and tension.          OK now please tell me where your multiplier is on the system your describing. A cable is attached to a frame = point A with a spring scale. This cable is ran thur a pulley= point B and this pulley also has a spring scale. Now you are returning the cable to a point that is in the approximate location of point A. You use a turnbuckle to tighten the cable. A cable that is free to self adjust.          As you tighten the turnbuckle tension is pulled thur both cable equally as the pulley is on a spring scale and the point A scale will come to term with each other. Why because the pulley will turn causing a loop pos+ to neg- reaction. The pulley is not a multiplier. You are still using one cable.          If you are using two cable with hard points. And you set both at 175# then you multiple by two. But the pulley or bellcrank will act as a neutralizer until so much drag on the pivot point cause it to freeze. And then as you tighten one cable the other will go backward in tension.             Multipliers, Ratios. Four hard point or three would do. Tighten both cable equal. However this is your higher math angle at which the cable attach.                                                                                                                                                                                                                                                                                                                                                                                                                                                         As for your personal notes. You best be happy with your life or change it. Life is to damn short.      Yes I though about the Air Force too. Just saw enough to know it was not for me.      Being tactful is the best part of valor. Sometimes we all forget. -----Original Message----- Warren, After reading your quote from Mr. Spani I can tell that we are not talking about the same thing.  The example that Mr. Spani wrote is 100% correct.  Nowhere in this discussion did I say that cable tension would be any different between the 2 cables.    If I may use Mr. Spani's example.  Lets use the same pulley system he described but this time we will also put a spring scale on the pulleys.  The spring scale would be attached to the bolt that would normally hold the pulley in place and then the other end of the spring scale would be anchored to something solid.  As you bring up tension on the cables the spring scales attached to the pulleys will read twice the force as the spring scale attached to the cables.  That means that the pulleys (not the cables) are being pulled together or toward each other at twice the amount of force than that which is being applied to the cables.    That is why a cable system that is set at 175 Lb of tension will exert 350 Lb of force on the attachment points of the pulleys.  That was the only point I was trying to make.  Sorry if things got a little ugly, it would have helped if we were talking about the same thing.  You have my apologizes.    By the way, I have to admit that just after high school I worked as an apprentice plumber.  Sometimes I wish I would have stayed with it, I would have probably made more money, then I could afford my own airplane instead of renting from the Base Aero Club.  Of course $65.00/Hr for a 2000 Cessna 172S isn't to bad, especially when we have 4 to chose from.  And then there is the T-34 at $72.00/Hr.  On second thought, I guess I'm happy with where I am.   Mavin Jones ----- Original Message ----    Your right, I must be as low than pig dodo. I surely cannot come up to you high standards. Wit, Master sergeant, A&P and Intellect that you are surely know best.    So in propensity I have come to ask your forgiveness. Because of my lack of humanity I now understand my place in this life. I make no dejected plead. March me out and feed me to the pigs.    But in my own defense I offer this. As you undoubtedly know for many years San Diego was the major player in Aerospace. We still have many of the Engineers still living and working here. Being a low life plumber I happen to have a few as customers. So I placed two calls today. If I am wrong I wanted to see the light. One who started out as a B17 / 24 maintenance person was out of town for the rest of the week. However Mr. Spani was home it evening. 858-485-1052 ask for Wayne.      “ This is not a mathematical problem. This is just common sense.” “Using one cable pull it around a pulley. The pulley will act as the bellcrank which is free to move. Using a spring scale to act as the tie end of the cable. When the spring scale reads x number of pounds the tensiometer will read very close to the same. (center of span) The only difference between the two cable is the friction drag of the bearing in the pulley or bellcrank.” So I am guessing he is also wrong? Yours, Warren H   ---------------------------------   --------------------------------- to unsubscribe send mailto:[EMAIL PROTECTED] ____________________________________________________________ T O P I C A -- Learn More. Surf Less. Newsletters, Tips and Discussions on Topics You Choose. http://www.topica.com/partner/tag01