---------------------------------------------------------- RV-List Digest Archive --- Total Messages Posted Mon 07/16/12: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 08:40 AM - Re: pitot system leaks (thomas sargent) 2. 08:59 AM - Re: pitot system leaks (Kevin Horton) ________________________________ Message 1 _____________________________________ Time: 08:40:12 AM PST US Subject: Re: RV-List: pitot system leaks From: thomas sargent I am still getting no where in testing my static system (or the static system leaks horribly). Does the connection to the VSI have to be sealed off before testing? I tried bonding a vinyl tube (perpendicular) to a piece of heavy clear plastic packing tape with GE silicone sealer. I cut a hole in the tape to open it to the tube and then pressed that onto the fuselage with the opening over the static port. I put a piece of packing tape over the other static port and sucked on the tube. I could get the altimeter and VSI to respond OK, but couldn't hold a deflection at all. I had to keep sucking a lot of air thru the tube. Air might have been leaking around the rivet that forms the static port where it penetrates the fuselage. When I stick the tape+tube down to a flat smooth metal surface, it seems to seal well. Some one said they used a veterinary syringe to draw a vacuum. How did you get that to seal to the static port? The opening in the port is 1/16". All of the syringes I have are significantly larger than that. -- Tom Sargent ________________________________ Message 2 _____________________________________ Time: 08:59:30 AM PST US Subject: Re: RV-List: pitot system leaks From: Kevin Horton On 2012-07-16, at 11:39 , thomas sargent wrote: > I am still getting no where in testing my static system (or the static system leaks horribly). Does the connection to the VSI have to be sealed off before testing? > > I tried bonding a vinyl tube (perpendicular) to a piece of heavy clear plastic packing tape with GE silicone sealer. I cut a hole in the tape to open it to the tube and then pressed that onto the fuselage with the opening over the static port. I put a piece of packing tape over the other static port and sucked on the tube. I could get the altimeter and VSI to respond OK, but couldn't hold a deflection at all. I had to keep sucking a lot of air thru the tube. Air might have been leaking around the rivet that forms the static port where it penetrates the fuselage. When I stick the tape+tube down to a flat smooth metal surface, it seems to seal well. > > Some one said they used a veterinary syringe to draw a vacuum. How did you get that to seal to the static port? The opening in the port is 1/16". All of the syringes I have are significantly larger than that. > > There is no need to seal off the VSI. But any of the pitot-static flight instruments could have a leak. It may be easiest to go at this piecemeal, only testing a small part of your system at a time so you can narrow down where the leak might be. You could disconnect and plug the forward end of the static line that comes from the rear fuselage to the instrument panel. Then see if you still have a leak. Then try a leak check on just the instrument panel portion of the system to see if that part is OK. -- Kevin Horton Ottawa, Canada ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message rv-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/RV-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/rv-list Browse Digests http://www.matronics.com/digest/rv-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.