Where can I find the torque value for the AN Fittings on the fuel tanks? Don't have my manual in front of my... but Im building in my head at work and dont want to snap these things!...
The values for 'performance' fittings are higher than those listed in the aircraft standards handbook. If i recall correctly a mid value for -4 fittings is about 50 inlbs and 100 for -6.
The .pdf document I linked is from Van's website (construction faq page) and, yes, there is discrepancy with values reported in AC43.13. (50-65 in/pounds for -4 and 110-130 for -6 fittings on aluminum tubes)
At this point, I imagine that is better to follow the AC 43.13, but... why Van's linked a "wrong" document? Or is it referred to something else?
Hmmm, there's quite a difference between these numbers shown on the pdf from Vans, and the AC document..... Should I torque them? Should I just do the hand tight plus 1/4 turn method? Im lost. Do I use the same torque value for the nuts that go on the sleves as well as the nuts that hold elbows in the tank?
Daniel,
I'm exactly at the same point as you. Today I planned to install the air vent and pick up tube in the tank before closing it, but without clear information on the torque value I'm a little in doubt. Before this thread I planned to use the Van's document, but now?
Ok Daniel,
after searching the forum, it looks the way to go is following the AC 43.13 or we'll end up overtorquing the fittings. Aeroquip "performance" fittings (the ones Van's document refers to) are quite different and requires an higher torque value.
Ok Daniel,
after searching the forum, it looks the way to go is following the AC 43.13 or we'll end up overtorquing the fittings. Aeroquip "performance" fittings (the ones Van's document refers to) are quite different and requires an higher torque value.
Ok, but Im still confused! (not hard really!) The AC43.13 says the torque values are for AN 818's... which I believe are coupling nuts. I DO have some of them.
But are the torque values listed in 43.13 the same for the nuts that hold the elbows in the end rib?:
I used the same values for both types of the same size, and ONLY use AC 43.13. After i saw the discrepancy with the Aeroquip pdf, I copied the AC 43.13 table and pasted it over the other (I keep these things inside the lid of my toolchest for quick reference).
Sweet. And what do I use to torque them with? I have a torque wrench... do I use on of those things that looks like a wrench head with a socket hole through the center? (yes thats a technical description )
That would be a crowsfoot. For calculating the torque, the math is:
T(W) = T(E) * L/L+E and
T(E) = T(W) * (L+E) /L
where E - Effective length of extension - measured along the centerline of the torque wrench. L Lever length of the wrench - center of grip to center of drive. T(W) - Torque set on the wrench. T(E)- Torque applied by the extension to the fastener.
the torque values from the standard aircraft handbook are slightly lower than those in AC 43.13. the table indicates the same values for aluminum alloy tubing, bolt, fitting, or nut.
A slight spin on the original question: How many of the pipe threads actually need to be utilized on an AN fitting? In other words, is the following AN fitting sufficiently threaded into the aluminum gear leg in this picture:
An identical AN fitting is included to show how deeply threaded the fitting in question is (5 of ten threads used).
Should I torque them? Should I just do the hand tight plus 1/4 turn method? Im lost. Do I use the same torque value for the nuts that go on the sleves as well as the nuts that hold elbows in the tank?
