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-   -   Help me understand Hoses and Fluids (https://vansairforce.net/community/showthread.php?t=168627)

TS Flightlines 02-10-2019 05:57 PM

The wing tubes to the fuselage--

Tom

mulde35d 02-11-2019 12:38 PM

Follow Up
 
Just wanted to close out this thread with what I finally decided. After about a day and a half of reading forums, researching materials, and searching places to buy parts, I have come to the conclusion that without a hose crimping machine at your disposal it is difficult to save money by doing the hoses yourself. The greatest factor is that the re-usable stainless steel hose ends are 3-5 times the cost of the crimp on fittings. That fact makes doing all the fuel, oil, and brake lines in conductive PTFE with SS braiding run somewhere around $1500 whether you have them done or do it yourself. This includes fire-sleeve for the fuel and oil lines along with all SS fittings.

With that being said, for now I have decided to likely have the FWF hoses completed by TS Flightlines / Aircraft Specialty (essentially the same companies for hoses) but still do the brake lines myself. While I don't think I will be saving much or any money by doing it myself, I want the experience along with the skillset so I can be better suited for maintaining the aircraft later in life. From what I can see so far the brake lines will need the following components which I priced out at www.anplumbing.com.

(All sizes are -3 hose and fittings for the brake lines which is all that is listed here)
Earl Speed Flex PTFE hose w/PVC coating - 4.48 x 30' = $134.40
Straight SS Speed Seal hose end - 14.29 x 13 = $185.77
45 Degree SS Speed Seal hose end - 49.82 x 2 = $99.64
90 Degree SS Speed Seal hose end - 47.08 x 1 = $47.01
Straight NPT to AN aluminum adaptor - 2.72 x 2 = $5.44
45 Degree NPT to AN aluminum adaptor - 8.35 x 2 = $16.70
90 Degree NPT to AN aluminum adaptor - 7.95 x 10 = $79.50
AN826-3SS AN-T w/ NPT - 25.95 x 1 = $25.95 (this is the firewall hardware in Stainless Steel)
AN924-3SS Bulkhead Nut - 3.95 x 1 = $3.95
Assorted Clamps, bolts, nuts, and Cable ties ~ $25.00

Total Parts Cost = $623.34

I also considered doing the hose fittings in aluminum, but that is not much cheaper than the SS fittings (only $2-4 difference) and Tom is right that the SS will hold up much better. But overall I am not worried about mixing aluminum AN fittings with SS hardware since it is all on the cool side of the firewall.

Off the www.aircraftspecialty.com website the above setup would be $549.95 for the standard brake line package plus $169.95 for the Gear leg hose kit. Total would be $719.90 plus shipping for materials, assembly, and pressure testing. So the total cost difference for having it done professionally vs do it yourself is only $96.56 plus shipping (for the brake system only of course). The 2 biggest differences would be crimped fittings vs re-usable and line testing. A big thanks though to both Steve and Tom for a good bit of shop knowledge and understanding of the system operation and pressures associated with the hoses.

While I am likely missing some small pieces in my list above (which if someone sees something please let me know) this is pretty comparable to having it manufactured and tested. I may be able to get the hose tested at my workplace, but I figure since it is only the brake system (as opposed to fuel and engine oil) I can likely figure out any problems without a catastrophic failure. Unless the brakes give out at a really inopportune time of course. In my mind this is the best way to get the maximum level of safety while still learning a new skill and maintaining a negligible price difference.

By the way, in reading some of the previous threads on this topic their were some pretty heated discussions on hoses. I guess I am just one of those who is more interested in learning the skills associated with building the airplane than the actual end product itself.


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