water up shaft tube

[BobHorowitz]

Hey folks,

I have a Zippkits Minisprint, built with their hardware kit. I grease the flex shaft, but I stil seem to get quite a bit of water coming up the tube. Anyone have any ideas on how to prevent this. The stub shaft is .156, as is the ID of the tube. The flex is about .130. I'm using the grease that Zippkits sells. Any thoughts would be greatly appreciated.

Thanks,

Bob Horowitz

 

[BrianTooms]

I put a short piece of water line, (vinyl type seems to last longer) half on the brass shaft and half over the flex.

 

[Wally Marsh]

Bob,

I've had a Mini Sprint for two years for introducing my grandkids to the sport, around 60 runs with it and zero water in the radio box. I quit shaft grease years ago, use only caster oil on all boats, I clean and "pack" the flex shaft with caster oil end of the day, maybe try that. Running stock 2S set up with Castle Thunderbird 54 esc and 2700 mah lipos, back cut stock pitch Octura X430 with leading edge tongues removed and blended consistently low 40s and 3 minute run times. Motor does get to 150-160 F so need to cool down between runs, I lightly oil periodically. I'm going to try 3S with speed control dialed down a bit, if it checks out will try 3500 kv brushless, I've heard 4400 kv is too high for 3S.

 

[BobHorowitz]

Well, I think I solved the water problem. I used a different grease and it seemed to keep the water out. This time I cooked the motor or the ESC. I'll check later. I was running a 3500kv outrunner with a HK Blue 60amp aircooled ESC, and a 430 prop on a 3s 2200mah battery. I guess it was too much. It worked okay with that setup the last time I ran it. Maybe the grease was too heavy, or I already started the damage last time I ran it and finished it this time.

Bob

 

[BobBonahoom]

I asked Joe what the setup was for the Mini running in the second video on the Zipp web site, which looked really fast. He said it was the 4400kv on 3S but the motor burned up in 2 minutes. They do say the 3500kv should work on 3S.

The first Mini I built snapped a shaft at the engine, filled up with water and sank to the bottom of the lake. Not a lot of room for floatation in it, so I did not have much. I have new one but have yet to try it. That was my first lesson re FE.