57-10-09 Wing Fold Fitting
57-10-09 Wing Fold Fitting Overview
Link to Builders Database for 57-10-09 Wing Fold Fitting
PDF 57-10-09 Wing Fold Fitting Install
PDF 57-10-09 Wing Fold Fitting
57-10-09 Wing Fold Fitting Installation Procedures57-10-09 wing fold fitting is a replacement for the old style "U" channel that was installed on the prototype aircraft. The fitting is fairly large because it has to fit around the 2 inch diameter forward spar tube. This left a lot of material outside of the typical airfoil cross-section. The new design will allow us to maintain the same wing fold system and is interchangeable with the old-style system yet is much cleaner, stronger, and lighter weight than the original design.
The pivoting wing fold bracket is held in place using an AN5 Bolt which acts as the primary pivot for the wing fold system. We will remove the old-style bracket and still use the original adapter (57-10-26 fuselage wing adapter) which fits inside of the 2 inch diameter forward crossover spar on the 4130 steel frame.
The new wing fold fitting attaches to the main wing spar on the inside rather than on the outside like the old "U" Channel. All the parts are shown together here.
With the two parts interfaced together you can see the nice clean profile that transitions the 4130 Crome-Molly steel fuselage directly into the wing fitting with no disruption. This will now act as the wing fold pivot during the wing folding process.
In this picture here we can see that the draft punch is not able to align itself properly because of the cotter pin interference. Because the wing fold pivots and the 5/16 bolt may rotate as well it's very important that the cotter pin not make contact with the cross bolt.
Click here for the Link to the magazine article on how your pin installation.
After proper installation of the cotter pin install a bolt or pin through the attachment hole to ensure that it does not make contact with the bolt before installing the assembly onto the 4130 steel fuselage frame.
Proper installation the fitting can be checked by affixing the fuselage adapter fitting into a vice and using your hand try to rotate the wing fold fitting. You should be able to rotate it but we would like to have as much pressure as possible just up to the point that it becomes very difficult to rotate. With a little Anti-seize compound in between the two fittings the fitting should rotate smoothly without being loose. Maximum torque on the castle nut should be limited to 140 inch pounds. But as with any castle nut the amount of torque necessary will depend on the alignment of the castle nut with the whole for the cotter pin.
The fitting should now be reinstalled onto the 4130 steel fuselage frame using the 1/4 inch AN4 bolt.
With all of the fittings now installed the wings are ready to bolt directly onto the fuselage assembly.