I dodged a bullet a couple days ago when I took my Hobie Hawk out for a flight after being dormant for at least 10 years. The xmitter is somewhat (~10 years) new but the receiver/servos go back to the 80s. It was risky but after 10 minutes of flying I managed to crash land with the receiver battery out of juice. I'd like to simply replace it, a NR-4QM but it appears to be of Unicorn rarity. It's a 3 wire connection so the question is, can i use a more modern 2 wire battery or is the signal wire significant, think I know the answer, yes? So failing that, what other options do I have other than upgrading the receiver, battery, servos and harness?

For your receiver you can replace it with any 4-cell NiMH pack. NiCads are a thing of the past. Your servos are old so I would avoid the higher voltage LiFe or Lipo cells.


The third/white wire on that pack does nothing. Only the Red/Black wires matter.

I'm curious, what purpose did/does the third white/grey wire serve?

None. It was an artifact of using servo wires already made up for the batteries. Most all come now with just two wires to avoid confusion.

Thanks Bill!