The Energy Limiter is a device which shuts off the motor after a certain amount of energy has been used.
Why do we use “Limiters”?
F5B pilots have always pushed equipment to the limit in the search for more performance and at the World Champs in 2004 a couple of battery packs exploded. At the World Champs in 2006 even more exploded, so it was time for a rethink of the rules. The idea of a minimum battery weight and a limit on the energy taken from it was suggested. George Shering proved it was possible by building the first limiter and so the rules were changed. Now it is safer because we do not push batteries to the limit. It is also cheaper because we need fewer of them, and it is more of a flying competition than a “battery race”.
Two types of limiter are available commercially – The Neu Limiter, and the SM UniLog. Both work reliably and accurately, but each has its own advantages. With its extra flexibility the UniLog costs about three times as much as the Neu.
The UniLog Limiter
A UniLog data logger with special software. Ideally you need access to a PC to get the most out of it and to update the software from time to time if needed, but you can change the settings to any class of model as often as you like with either a PC or the little UniDisplay screen designed for use on the flying field. The voltage, current, and height are all recorded during a flight, and can be displayed later on a PC or in a more limited fashion on the UniDisplay. Temperatures, rpm, and speed can also be recorded with accessories.
The Neu Limiter
A simple plug and fly device with different versions available for F5B, F5D, and F5F. There is no data log or read-out, and it cannot be adjusted so if you want to fly a different class you have to buy another limiter. It is very simple to use – you buy the version for the class you fly and fit and forget it.