I have been attempting to measure the static thrust of my EDF with a spring balance. It is part of a group university project. The EDF specs are as follows: 90mm freewing 9 blade 1900 Kv thats rated at 4000g (<https://www.rc-castle.com/index.php?...roduct_id=8798>). It is being powered by a 6s lipo battery. I made a wooden stand to screw the EDF on. The stand is then attached to the metal sliders. I attached a spring balance to the wooden stand. So when the EDF turns on, the stand slides foward. The spring balance is pulled and the value can be read off it. However, I am unsure if this method is viable as the spring balance is marked incrementally in Kg. I can see this being useful if I hung masses vertically off the spring balance and wanted to measure it, but in my case, I'm trying to measure the force ''horizontally'', if that makes sense.

In summary, I was not sure if I was using the spring balance correctly. Any advice is appreciated.

On the side here are some test results: The EDF at full throttle pulled the spring up to the 3.1kg mark. The lipo was fully charged. I have attached some pictures of it: [![enter image description here](https://i.stack.imgur.com/p0aP3.jpg)](https://i.stack.imgur.com/p0aP3.jpg) [![enter image description here](https://i.stack.imgur.com/qMAWt.jpg)](https://i.stack.imgur.com/qMAWt.jpg) . I assume the friction between the rails is responsible for the lower thrust value.