Sir thank you so much now I understood how it works!

@KK Iyer sir how would it be able to measure thrust when the block is rising?

Iyer Sir, what I am trying to say is while measuring the thrust in tractor configuration how will we get the readings when the  lock is being pushed away and not pulled.

Please bear with me, I am not so good in physics and are my above drawings right?

Try this simple setup. Ensure that the thrust is downwards by ensuring that the front portion of the prop is pointing downwards and setting the direction of rotation of the motor so that thrust is downwards.
Exercise caution while taking readings as the blade is horizontal and not visible when turning. Also ensure that the block does not topple due to vibrations and cause damage/injury.

Nitesh,
I've seen 3 models in the forum.
1. Tractor. Sanjay sir's tension model. A trolley with wheels. Thrust measured by a spring balance type scale in tension.
2. Tractor. Baijal sir's fulcrum model. Motor pulls vertical arm, horizonal arm presses on flat type electronic scale.
3. Pusher/tractor. My Brick model. Used normally in pusher mode, so that the thrust presses the scale down. When you keep the device on the scale, it reads about 2.7kg. Pressing the Tare button zeros it. When motor runs in pusher mode, scale shows a positive value. When in tractor mode, it shows a negative value.

In tractor mode there is the danger of liftoff!

Model 1 can be used in pusher mode by attaching the spring balance to the other end 
Model 2 can be used in pusher mode by keeping a weight (more than expected thrust) on the scale and zeroing it.

After these long lessons  here's an experiment for you:
1. Is there a difference in thrust between the two modes? Why? Is there much difference?
2. Does fitting the prop one way or the other make a difference?
3. How does a pusher prop compare with a normal one of same size, shape and brand?

It would be nice if you try the above and report results on the forum.
Regards (BTW, hope you saw my PM on a different topic!)

A small clarification.  My setup works on both modes. The motor mount is reversible as described and pictured in earlier posts.

Here's my bit to it ..... A design in which the applied thrust is not in line with the measuring device a moment arm is created and hence the reading would be less than the actual thrust .

Here's my design where in I have tried to keep the measuring device in the line of thrust .

(P.S.   Even in this design, the measured thrust would be slightly less than actual, as that part needed to over come the friction in the channels goes unmeasured, but that can be calculated and kept as a standard addition )

  reminds me of our earlier discussion

Yes Sanjay Sir . ... No doubt you have a sharp memory

rcnitesh you need to place the motor on the other side for pusher

Thrust meter built with sketchup

https://drive.google.com/file/d/0B1PSuFLMpZcFZG1IX0MyWHNkV2c/view?usp=sharing

sketchup version.
https://drive.google.com/file/d/0B1PSuFLMpZcFMUFzaFEzZDJxRzQ/view?usp=sharing

Forgive me for any mistakes and point it out.

With regards,
Nitesh

Nitesh,
Come on, surely you can do better than this!
Regards

Sir can I know how? Is there any mistake in this design? I am going to start the build tomorrow because till today I was scavenging around for the materials :p.

With regards,
Nitesh

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Have a look a ... A simple thrust measuring setup.. myrahulroy.blogspot.in/2016/01/motor-testing-rig.html?m=1

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