The right hose and AN fitting. They are not that expensive and easy to use, safe and why doesn't everyone use them. la...@lebanair.com
-----Original Message----- From: krnet-bounces+larry=lebanair....@mylist.net [mailto:krnet-bounces+larry=lebanair....@mylist.net] On Behalf Of Donald Greer Sent: Saturday, December 18, 2010 7:36 AM To: KRnet Subject: Re: KR> fuel system fittings Dene, I believe that the only flexible hoses which will get the nod from your inspector are the MS28741 series rubber hose assemblies. These hoses are rated for use both inside and outside of fuel tanks and, unlike a single barb with band clamp, have a threaded barb which engages the inside of the hose and a threaded collar which engages the outside of the hose to 'clamp' the hose to the barb (note - if you have not seen them before, they are not flare fittings). As others have noted, flexible lines are heavier then rigid lines, but they do have their place. Specific examples of usage would be input lines for pressure transducers or carburetors and output lines for fuel pumps, where flexing caused by changing pressure or vibration from pump/engine operation would have a detrimental effect on rigid lines over time. For aircraft applications, I absolutely agree with the opposition of others to the single barbed connections. This is one of those aspects of aircraft construction where I believe that one cannot compromise safety for the sake of saving a couple of dollars. My two-cents worth, Don Greer Belleville, Ontario On 18-Dec-10, at 5:38 AM, Dene Collett wrote: > Guys > I know this is a contraversal and sometimes touchy subject but I > need some clarity. > There is widespread condemnation of the practise of using barbed > fittings and hose clamps in an aircraft's fuel system plumbing. > Could somebody in the know please tell me why this is so. I can't > think of any reason why using a good quality reinforced "rubber" > hose with fire sleeve over it (forward of the firewall) would be in > any way inferior to using aluminuim piping and AN fittings. In the > event of a mishap and things move around, I can't see how the solid > installation will be superior to the rubber hose as it will not have > near as much flexibility to absorb the movement. I would imagine > that an aluminuim pipe would be much more prone to cracking and > leaking when kinked. > > Over here the practise of using barbed fittings and flexible hose is > almost universal unless you are assembling a RV kit which comes with > all the appropriate AN fittings. > Am I missing something here? > > Regards > Dene Collett > Avlec Projects cc > Port Elizabeth > South Africa > _______________________________________ > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > please see other KRnet info at http://www.krnet.org/info.html > _______________________________________ Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net please see other KRnet info at http://www.krnet.org/info.html
