Fuel lines for 1948 C170

[2Georges]

Hello all,
I need a little help. I am trying to properly install the original fuel system in my 1948 C-170. I was able to acquire some very technical data as to the specifics of the installation as a favor directly from Cessna. However, regarding the material used to manufacture the fuel lines to and from the fuel pump, the drawings I have list the material as EVERDUR and the material specs as COMM. Cessna is doing further research, but as of yet has not turned up the exact alloy used originally (several variants are currently available under the commercial name of EVERDUR). In the mean time they suggested using flexible lines or stainless steal. My preference is to find and use the original material (the restoration has been extensive and mostly very original) to fabricate new lines. As a second option, I would be happy to use stainless, but I am somewhat concerned that the stainless might not have enough give for the continuous vibration. I believe the copper in EVERDUR was used as much for its good fatigue resistant qualities as for its resistance to corrosion. Any information would be much appreciated. Also, I wanted to mention that after a lot of searching, I located a vendor for the elusive fuel check valve in California. The price was $200 ( I talked him down from $250) from El Dorado Aircraft and I was told that price would be passed to any Association members. The valve was brand new and only required the removal of the spring to comply with Cessna's installation. If anybody has further questions, I would be happy to help.

Thanks,
Andy George cell 740 973-7041

[GAHorn]

I received an email from Cessna last week about the check valve. (Cessna had called to ask if we had any specifications for the part, as the factory no longer had any data.) Here's the "official" response to my inquiry as to their lack of support for that check-valve:
"George,
A new Cessna Standard has been setup as a replacement for the old check valve on the 1948 Model 170 that is no longer available and hard to acquire.
The new part number is S4176-1. The lead times will be a little long since this is a brand new part but you can call the Cessna Spare parts organization for an estimate.
Thanks for all your help.
(signed)"

Meanwhile, 2Georges, copper is NOT a good fuel-line material. Copper does NOT have "good fatigue resistant qualities"....in fact, copper is HAZARDOUS when used for flammable fluids due to it's proclivity to become work-hardened and brittle when subjected to vibration. In other words, in a vibration-environment, it's only a matter of short time before it CRACKS!

Flexible lines are the best solution, in my opinion. I suggest you use certified, teflon-lined hoses from an aircraft-hose supplier. They will make them with any length and any fittings you need. Aircraft Spruce also mfr's hoses via their vendor. 877-477-7823

http://www.aircraftspruce.com/catalog/a ... uip666.php



Even better, use 466 firesleeved hoses:
http://www.aircraftspruce.com/catalog/appages/ae466.php

[n2582d]

I shared George's concern about fatigue cracking of the '48's metal fuel lines here. But on further study I think I may have been overreacting to the perceived danger. As Andy pointed out these lines are not soft copper lines like you would find in a hardware store. Everdur is "a brand name for any of several alloys of copper and silicon with other constituents, especially manganese, ... ." I have not heard or read of any of these fuel lines cracking on straight C-170s. In the Feb. 1932 issue of Motorboating on page 197 I found this paragraph in what appears to be a multi-page advertisement by Anaconda mining company:

The smaller diameter oil pressure line has been known to crack, so whether that is made from Everdur or plain copper, I think it should be replaced with a hose as has been discussed elsewhere on this forum. If any have heard of these Everdur fuel lines cracking please share the details.

[hilltop170]

Or replace the instruments with new digital instruments that don’t use pressure tubing and have the transducers placed in front of the firewall.

[GAHorn]

Or replace the instruments with new digital instruments that don’t use pressure tubing and have the transducers placed in front of the firewall.

That’s a rich-mans’ solution to a simple pressure-line replacement... a hose to replace that line cost less than $100... considerably less expenive than new digital intruments that don’t look like they belong in a 1950s airplane. (Not that my digital avionics do either...).

[DaveF]

That’s a good suggestion, Richard. Not only do you avoid the problem of running oil and fuel into the cabin, you also get greatly improved instruments. And as your airplane’s panel demonstrates, it’s possible to do that and still retain a classic appearance.

[hilltop170]

Thank you Dave. Not only are the digital instruments safer due to no pressurized hydrocarbon firewall penetrations, they are much more accurate. And in all of the years I have used digital instruments, close to 30, I cannot recall one failing or having to be recalibrated. They just work, but to each his own, if you don’t want to use them, don’t, I just make suggestions based on my own personal experiences.

[GAHorn]

Yeah, I need to apologize for my earlier comment... I didn’t mean to come across that harshly. Richard has taken especially good care of his airplane (all of them in fact) and his solutions are certainly technological upgrades. (And he has a good eye for beauty in all matters, if you know what I mean.)