How often do you inspect your fuel lines?
03-27-2017, 01:21 AM
#28
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I have managed to get some stainless piano wire to do the proper job for the piece of mind securing all the fuel nipples under the front cover, complete replacement of all fuel lines while using also new pump I had as a spare from Wren set up. This time I have also simplified my fuel shut-off system by installing tiny little gadget, 'PICO', an electronic circuit breaker fitted to the fuel pump power leads, thus eliminating my original servo operated valve. After good check of plumbing it's all back inside model.
03-28-2017, 11:47 PM
#29
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After major service I gave it today first run to re-calibrate the system after installation of different pump, first start, ramping up little too hot with the old fuzzy logic memory shutting itself off after short run time, minor reduction of start up ramping value sorted it out while teaching it the new system. All good, ready for action.
03-29-2017, 01:38 AM
#31
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Maybe in your book, but I have been using this sort of hook up last 11 years in all of my 7 turbine models I built to date, I only remember few flame-outs in one of my own design turbine powered model with "Wren44G" due to the wear and tear faulty pump, after replacement all back to norm. I only recommend to everyone regular check of fuel system for safe operation. Next few days I'm pulling out my other engines to check the state of the fuel lines under the engine cover, looking forward to it, stay tuned.
03-31-2017, 12:40 AM
#32
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After pulling out another engine the blue gas line was partly broken in two places and finding all fuel lines in very poor state, stiff and brittle just about to fall off the nipples. Time to do another major service to all plumbing!
03-31-2017, 04:39 AM
#33
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Push in festo style fittings seal on outer diameter with pressure applied internally to hose inner diameter, by design Festo used to only show a spec for sealing pressure, when first designed they never showed a vacuum spec. Within industry automation, and the vast use of vacuum cups to hold things it's pretty common to see most vendors using Festo style pushin fittings on vacuum circuits, I have even seen a vacuum rating of the fitting on some brands, nowhere close to absolute.
I am old school and sucking a hose away from the outer diameter o-ring keeps me up at night, I personally only use the barbed nipple and wire or the festo type seen on BVM UAT for suction sides of plumbing. IF I have no choice I will insert the ID brass doohickey commonly used in ice maker type tubing to ferrule fittings to keep from collapsing.
Within industry automation design reviews, I have spec'd out and proven over and over that hose barb style fittings only, on suction circuits, will produce superior results over pushins in amount of vacuum integrity to absolute vacuum, and allows me to sleep at night.
I am old school and sucking a hose away from the outer diameter o-ring keeps me up at night, I personally only use the barbed nipple and wire or the festo type seen on BVM UAT for suction sides of plumbing. IF I have no choice I will insert the ID brass doohickey commonly used in ice maker type tubing to ferrule fittings to keep from collapsing.
Within industry automation design reviews, I have spec'd out and proven over and over that hose barb style fittings only, on suction circuits, will produce superior results over pushins in amount of vacuum integrity to absolute vacuum, and allows me to sleep at night.
03-31-2017, 01:53 PM
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I'm talking about the fuel lines/gas lines inside the front cover of the jet engine, in my case both engines are over 10 years old. When did you check yours?
03-31-2017, 02:16 PM
#36
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Sorry - I was talking just about the Tygon portion of the fuel system. Turbine is relatively new and things look great under the hood last time I looked a few months ago when I changed an O-ring. The poly fuel lines from the pump to the turbine are all original though and they are in fine shape also. I cut the ends back some after a few connects/disconnects from the turbine. Sorry for the confusion.
03-31-2017, 04:21 PM
#37
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Replaced my Starter O-ring on my JetCat P-80SE and found one of the internal supply hoses partially melted with a hole in it.
Was melted right at the wire-wrap. Almost looked like someone hit it with a solder iron during assembly maybe of the starter motor.
Was melted right at the wire-wrap. Almost looked like someone hit it with a solder iron during assembly maybe of the starter motor.
Last edited by TJP; 03-31-2017 at 04:24 PM.
03-31-2017, 11:49 PM
#38
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Pilots would find lot of surprises if they remove the front covers of their engines after years of usage. I'll be definitely doing it now on the more regular bases. Next job will be the tiny little "Wren 44G", I'm not looking forward to it after the ******* of the job shaping and fitting it in my larger ones.
