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bryannortje
24-11-14, 14:45 PM
Hey fellow Nynja (Skyranger) owners

I have just submitted a minor mod app to BMAA for an ESS (engine soft stop). I have the Rotax 912ULS engine fitted and with this mod am able to cut the engine after flight without using the Mag switches. It makes for a nice smooth engine cut and should help to prolong the life of the gearbox, slipper clutch, engine mounts, carb rubbers to name but a few. I have used this for quite a while now to ensure that there are no lurking gremlins and its brilliant. Weight gain only 52g and this dependent on a few factors in cable inner and outer lengths and pull knob size as well as where its mounted on the Instrument Panel.

See attached pic's. All parts (except for the pull knob) available from Flylight.

Enjoy the pics.

Ok I'll to try explain the Mod and how it works....

In the Skyranger range of aircraft (Original Model, Swift and the Nynja) when
installing the Rotax 912UL and 912ULS, part of the engine installation and set
up is to remove the Throttle Idle set screws (on the carb butterfly stops) As
the engine idle is set (after one has balanced the carbs) by adjusting a cam
type stop on the throttle lever arm these screws are not required. As a result
of this installation, one is able through the by way of my Mod to pull the carb
butterflies fully closed while the throttle is in the idle position. The result
is thus closing both the fuel and air supply to the Engine which results in a
gentler stop than that achieved by using the Mag's to kill the spark.

This is much the same way as the GA aircraft guys kill their engines by
leaning off the fuel mixture and thus the engine cannot sustain Idle and
therefor dies. I just have to ensure that I dont forget to switch off the mags
(most microlights kill their engines by switching off the mags) and GA guys tend
to all have a master keyed switch linked to the mags / starter.

I would add that the Skyranger Aircraft types, due to throttle linkage /
operation set-up lend themselves very well for this type of mod. Not sure
without looking at other aircarft types what other's this would suit.

I hope this helps anyone understand it a bit more.

Cheers

Bryan

CT Aviation
24-11-14, 17:48 PM
52g ! Can you afford that amount of weight increase Brian ?

bryannortje
24-11-14, 18:05 PM
Yeh - thought i would just replace the battery with a half charged one :scratchheadblue:

CT Aviation
24-11-14, 18:16 PM
That'll work, just like the bendy composite on a certain F1 car !

bryannortje
25-11-14, 12:38 PM
Really confused :rolling: