Twin Power Management on Water

Definitions:  For the purpose of this discussion, the term inboard is used to reference the engine(s) on the inner side of the turning circle.  That is, the wing that travels the least arc when turning.  For example, in a right turn, the right wing travels the least and is deemed to be the inboard wing.  The wing that travels the greater arc is defined as the outboard wing.

Those who fly radio-controlled float planes and seaplanes know that when conditions are windy, steering on water can be a problem.  The craft tends to weathervane into the wind and the effect of water rudders may not be enough to overcome this tendency.  For those who fly either electric or glow twin powered planes, this project is a solution.

It would be hazardous to have unbalanced power in the air, so this option is selected only when taxiing on the water.  It is activated by the GEAR channel.  You can think of it as dropping the water rudders.  Float flyers know that real planes lift their water rudders once lined up for take off and drop them only once safely on the water.

Note: You should have the input from the rudder on a Y harness. If the PIC burns out, you still want signals to get to your rudder directly!!!

Two concepts are presented.  The first locks the inboard engine at idle (glow) or off (electric) while letting the outboard engine follow the throttle curve.  The second locks the inboard engine at the throttle setting when steering is selected and the outboard follows the throttle curve.

The throttle is linked to the rudder stick, so the combination of water rudders and power differential can be used to steer on the water.

Caution:  These programs have not been tested on real radio-controlled aircraft.  The information is presented only as a concept.

Equally, as written, the inboard servo that either goes to idle (version #1) or is frozen at initialization setting (version #2), recovers to the setting of the outboard servo once the rudder is neutralized.  This abrupt change may be too much sudden change for both a glow engine and an electric setup.  A softer recovery is provided in versions #3 and #4. 

Based on a suggestion by Mr RC-CAM, throttle kill on loss of signal was added to version #5 to prevent glow "fly aways".  It is available as version #5.  In version 6, the throttle goes to idle rather than killing the engine completely.

The download includes the PicBasic Pro PBP and Hex files.

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Last modified: March 18, 2004