NEW! Ultimate C/S Prop Wrench Anti Splat Aero

[CMW]

Sorry, but I don't agree with that. Get a one-foot ruler out and have a look at it; does that look like the length of the sort of torque wrench you'd use on 7/16" nuts? Remember, we are talking about a wrench specifically designed for propeller nuts.

Bob, you're probably right. I just based that statement on the fact that my 100lbs-ft clicker wrench happens to have a 12 inch effective length. My old beam style wrench is 17" (weird).

Mike,

There is no way I can hold that much if it were a simple lever.

I don't know, you look pretty stout.

[Captain Avgas]

Originally Posted by LifeofReiley

JMHO... this Gentleman, Allan has PAID for advertisement space on VAF. He has posted a Classified Ad, not a discussion thread. At what point do stop beating on Allan for his PAID advertising? If you like his products, buy them. If you have a question about them, call him. If I remember correctly folks getting BANNED for beating up PAID adverisers here on VAF...

Well, in the words of Doug Reeves himself, VansAirforce is "a place for people building and flying RV kitplanes to socialize, network, get inspiration and receive help from others". My best guess is that the current discussion falls firmly into the latter "helping each other" category. There are obviously many educated people on this forum who firmly believe that Allan is providing incorrect, and potentially unsafe, information and they subsequently feel an obligation to point out that fact to others. And in my opinion they would be morally bankrupt if they did not do so.

[444TX]

I can not wait to see Allan's video example. He is completely correct and knows it. For many it will be very educational

The biggest problem is the poor formula for torque extensions. Allan's example in post #22 is no exeption.

When converting, 12 inches is always used with ft/lb and 1 inch is always used with in/lb for "L" in the equation. This applies to all types of torque wrenches when using the indicated reading on the wrench.

If the handle length is used the amount of neccessary force applied to the handle is calculated and would have to converted back to ft/lb's.

George
RV8

[WAM120RV]

So, I have 2 foot long torque wrench but instead of pulling it at the handle, I decide to pull it in the middle 1 foot down its length.......will this alter the setting required.

It seems to me that a lot of intelligent people are getting themselves tied in knots trying to understand whats going on here.

For Allans extension spanner to provide 100lbs/ft at the nut, it requires a certain pressure applied at the attachment point to the torque wrench. The amount of pressure will not change no matter how long the torque wrench is. What will vary is the amount of pressure applied by the operator to the torque wrench handle, and the amount of stroke required.

Think about your joy sticks and the effect of varying their length. The loads on the control surfaces dont change, but the load you have to apply to the stick does vary, and the amount you have to move it.

Your mileage and stick length may vary

[380mxc]

Can someone show me how the formula in AC43.13-B figure 7-2 for the torque wrench adapter is wrong.

It dissagrees with using .8 as a constant.

My torque wench manufacturer says the handle length is 22.57 inches and my extension is 3".

If the formula from AC43 is used, 70.61lbs shoud be my setting on the wrench
If the .8 constant is used, 64lbs should be my setting on the wrench.

Thanks for your help
Tim

[fehdxl]

Originally Posted by 380mxc

Can someone show me how the formula in AC43.13-B figure 7-2 for the torque wrench adapter is wrong.

Nope. AC43.13-B is correct. Y=(T*L)/(L+E)

-Jim

[WAM120RV]

http://www.freeinfostuff.com/TorqueE...eExtension.htm

[Bob Kuykendall]

Originally Posted by WAM120RV

So, I have 2 foot long torque wrench but instead of pulling it at the handle, I decide to pull it in the middle 1 foot down its length.......will this alter the setting required...

It depends on the type of torque wrench being used. For a clicker or dial indicator type, the indicator or click will be accurate, since the measurement is entirely internal to the wrench. However, you will have to apply twice the force at the 1-foot mark as you would at the handle to achieve the same torque at the nut.

Edit add: It turns out I might be wrong about part of this. A video linked from a later post seems to demonstrate that applying force to the middle of a torque wrench will disrupt its accuracy. However, it does not sway my conviction about the invalidity of the "0.8 correction factor."

For a beam-style wrench, the indication will not be accurate if you apply force at any place except at the handle. The accuracy of the indication scale near the handle depends on the beam being loaded in simple bending by a force applied at the center of the handle. Most such wrenches have a rocking pivot built into the handle that ensures that the force is applied to the beam only at the correct point.

Originally Posted by WAM120RV

It seems to me that a lot of intelligent people are getting themselves tied in knots trying to understand whats going on here...

It seems to me that a lot of people are putting a lot of effort into clarifying what is going on because it is a safety of flight issue with potentially deadly consequences.

Originally Posted by WAM120RV

...For Allans extension spanner to provide 100lbs/ft at the nut, it requires a certain pressure applied at the attachment point to the torque wrench...

Statements like that tend to be the places where this discussion goes off the rails. We are not talking about pressure here, we are talking about forces and torques. Those three things are very different and have very specific meanings. We have to keep our terms straight in order to discuss this intelligently.

A force is, well, a force, aplied at a point. Forces are measured in units like pounds or Newtons. A pressure is a force applied over an area. The air in your tires applies a pressure something like 30 lbs per square inch to the inner surface of the tire.

A torque is the result of a force applied at some distance from an axis that causes bending or rotation. Torques are measured in in-lbs, ft-lbs, Newton-meters, and things like that. An inch-pound is the torque that results from a force of one pound applied at a distance of one inch from the axis. A Newton-meter is a force of one newton (there are nominally 9.8 newtons per kilogram) applied at a distance of one meter from the axis.

You might ask, if the Metric system is decimal, why are there 9.8 Newtons per kilogram, and not ten? It's because the Newton is a measurement of force that is independent of the 9.8 meter-per-second^2 acceleration of gravity. But that might be the start of a discussion for a different day.

Thanks, Bob K.

[Bob Kuykendall]

Originally Posted by WAM120RV

Try this link
http://www.freeinfostuff.com/TorqueE...eExtension.htm

Nice, thanks for posting that! It is a good description of what is going on, and the calculator makes it easy to test different combinations of wrench length, extension length, and torque value.

Thanks, Bob K.

[WAM120RV]

Bob

I totally agree about the potential dire consequences, and forgive my poor choice of words, should have said force.

I think the point I was trying to make is that there are a lot of opinions and calculations going on here which I suspect would cause more confusion. Also trying to put a light side on the thread.

Bottom line is if you search the web there is usually a calculator set up to do the mathematics for you.