Looking around I could only find one, made in the states and sold over here by Pro-Build for ~£25. On closer inspection of the pictures it looked very much like a clothes peg with a scale and bob-weight attached, so being a mean so-and-so, I thought “I can make that”. So I did, and it is shown in the various pictures.
At this point I should perhaps make it clear that it hasn’t,
so far, improved my flying (who said we noticed…!), but it has been useful in
the following ways.
The first model I applied it to was my 68” Glens Extra. This is lovely precise model to fly but at the time had a slight tendency to ‘screw’ out of loops and bunts. It has a split elevator driven by separate servo on each side. Application of the Throw Gauge to each half revealed that one side was moving further ‘up’ than the other, by a significant 10°. Using the gauge and adjusting the electronic trims for each servo quickly cured this problem, and definitely showed up in the flying.