Torque Meter Design info

[coachchuckaahs]

Gary HInze has posted a very detailed look at wire torque meters for heli at https://www.endlesslift.com/steel-wire- ... er-design/

There are several important and interesting concepts presented here. However, the most important one is that most of the "simple" wire torque meters will reach plastic deformation within the range of torque needed for heli! In fact, based on his data, the minimum wire size would be 1/32" music wire, which is quite thick compared to typical indoor torque meters!

A reasonable length of 1/32" wire would not give a full rotation for torques of interest (many are winding over 2.0 oz-in). So to have a practical wire TM you would have to expect substantially less than a full turn.

I have not checked the data in detail, but his findings certainly jive with very cursory looks I have used.

The bottom line is that these heli's take a torque much higher than a typical indoor free flight model. This is why we have warned about using certain precision torque meters and winders which are not made for this level of torque.

The load-cell-and-arm digital torque meters will generally support these higher loads.

This article is a great read if you want details on wire torque meters.

Coach Chuck