Anyone know the correct full scale currents for the typical gauges used with Rotax 2-strokes? Please form an orderly queue.
While replacing the senders I checked the FSD current with a resistance box, 2 Volt cell and a multimeter. The milliamps for my 15 year-old dual gauges are:
EGT 2.67 2.54
CHT 1.72 1.85
Those are small percentage differences, except that the EGT pointers (correctly) don’t move at all until a certain current flows, so you’re only really seeing the top end of a much larger scale – the bottom part of the scale is ‘hidden’ if you see what I mean.
For the same gauge current there’s a significant difference in the reading with the EGT but much less difference with the CHT gauges because they seem to have linear scales.
Sure enough the lower current EGT side reads higher in flight - and uncomfortably close to 1200 F at times - hence this post.
Makes a bit of a mockery of Rotax’s specification of not more than 43 F difference between the cylinders. |
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