I have designed my fuel system including an 8.5 gallon header tank that must be attached to the fuselage. What are the good schemes for attaching it to the firewall? Why are those the good schemes?
I have come up with several schemes using four hardpoints near the forward corners of the tank allowing me to secure it using threaded fasteners. All of them have generous FOS on everything from +/-6g flight to the 26g forced landing pulse.
The first uses fiberglass angle fittings on the firewall and fiberglass T's on the tank, with AN bolts and self locking nuts in double shear;
The second uses fiberglass angle fittings on both firewall and tank, with AN bolts and self locking nuts in single shear;
The third uses four ClickBond studs on the firewall, fiberglass angle fittings on the tank, and self locking nuts.
I can also fabricate positioning features on the tank and firewall, then run a couple padded straps with bolts through the firewall to tension the straps.
Which ones are bad ideas and why? Which are good ideas and why? What other ideas exist for doing this, and why are they good ideas?
Billski
I have come up with several schemes using four hardpoints near the forward corners of the tank allowing me to secure it using threaded fasteners. All of them have generous FOS on everything from +/-6g flight to the 26g forced landing pulse.
The first uses fiberglass angle fittings on the firewall and fiberglass T's on the tank, with AN bolts and self locking nuts in double shear;
The second uses fiberglass angle fittings on both firewall and tank, with AN bolts and self locking nuts in single shear;
The third uses four ClickBond studs on the firewall, fiberglass angle fittings on the tank, and self locking nuts.
I can also fabricate positioning features on the tank and firewall, then run a couple padded straps with bolts through the firewall to tension the straps.
Which ones are bad ideas and why? Which are good ideas and why? What other ideas exist for doing this, and why are they good ideas?
Billski
