Prop shaft sealing methods

[Jsmeberg]

Hi all,

I've been reading up on shaft sealing technologies as well as the common methods used to seal RC prop shafts as they go through the hull. I'm wondering why its not more common to see standard oil seals/lip seals used as opposed to stuffing boxes or stuffing tubes? Lip seals are used on the prop shafts of outboard motors made by Mercury or Yamaha so why not for the RC application? Let me know if somebody has an answer or experience with this.

Thanks!

[NativePaul]

Full size outboards don't use flex shafts. Flex shafts need to be supported all along their length to stop them being turned into a pretzel, that is what the stuffing tube is for in most cases with model boats.

Many people do run an oil/grease seal on the inner end of the stuffing tube, which is easily made by slipping a short length of silicone tube, or heat shrink tube over the end of the stuffing tube so it grips the stuffing tube firmly, and just touches the flex.