Model Boat Mayhem

The Shipyard ( Dry Dock ): Builds & Questions => Submarines => Topic started by: Korp1010 on April 12, 2017, 05:30:34 pm

Title: R/C Sub U47 questions
Post by: Korp1010 on April 12, 2017, 05:30:34 pm
Hello all,


I've built a Robbe U47 submarine which has had some heavy modifications from original using a different tech rack, Engel dive tank and a Norbert Bruggen locking ring. As the kit was never designed to use this type of system I've had to piece together bits of information and components from quite a few places and i'm very nearly finished but have a few questions I could do with an expert answer on please.


1, For the two push rod seals that exit the rear end cap I currently have two 10mm pieces of tube with rubber bellows fitted secured with metal clips but I have doubts as to how reliable these are as if one of the bellows splits or comes off then the sub would flood fast. I have seen smaller type push rod seals that use a small o-ring and are no wider than the push rod itself so wonder which way is considered better?


2, I purchased a Sub tech APC-4 leveller quite a while back and would like to know if this is still a competent leveller for the 1.7 meter sub or should I be looking at a newer Engel version.


3, Finally should I be fitting an Engel pressure switch to the sub as I never intend do dive it down past 1,8 meters as our club sailing water is only 2 feet deep although I know the switch also senses pressure loss in the WTC so if I have a leak it prevents the sub diving/ blows ballast if it has done already.
Title: Re: R/C Sub U47 questions
Post by: tsenecal on April 12, 2017, 08:41:09 pm
Not sure on point #3, but for #1 and #2, I have a u47 that has also been updated with an engel dive tank, but has retained the robbe pushrod seals, and over 3 years of use, there was never an issue with the pushrod seals.  the APC-4 leveler is still a capable device, if you have it, it will work, no need to replace it.
Title: Re: R/C Sub U47 questions
Post by: Korp1010 on April 12, 2017, 09:43:32 pm
Not sure on point #3, but for #1 and #2, I have a u47 that has also been updated with an engel dive tank, but has retained the robbe pushrod seals, and over 3 years of use, there was never an issue with the pushrod seals.  the APC-4 leveler is still a capable device, if you have it, it will work, no need to replace it.


Thank you for your reply, have you used one bellow on each push rod or fitted one inside the wtc as well like a double measure?
Title: Re: R/C Sub U47 questions
Post by: tsenecal on April 12, 2017, 11:10:28 pm
i actually ended up using 3 of the original bellows, one for rudder, one for rear planes, one for forward planes.  all three were on the outside.