Orndorff has you do three things:
1. Bend a curve
2. Bend a angle
3. Twist the longerons
This is his procedure:
1. Clamp Longerons together, it should look like a "T"
http://i50.photobucket.com/albums/f307/Degan367/Bend.jpg
2. Mark them at 28 1/4"
3. Mark them at 38 7/16"
4. Mark them at 69 9/32"
5. Double check measurements against plans as they may have changed.
Place the longerons in vise with the "T" shape down in the vise. Vise does not need to be tight. Leave it loose enough to slide the longerons. Start at the 28 1/4" mark and use your body weight to bend the first curve and slide the longeron a few inches at a time and keep bending. If a clamp gets in the way, just move it. Put the F-712B canopy deck forward edge to the 28 ¼” mark on the longerons and use it as a template since the curve is already cut into it. Keep tweaking it until you get the curve you want.
http://i50.photobucket.com/albums/f307/Degan367/Bend2.jpg
Now that the curve is complete, clamp the longerons at the 28 ¼” mark and tighten it in the vise. Grab the first longeron and pull it toward you until the distance is 2 ¾” away from the other longeron.
http://i50.photobucket.com/albums/f307/Degan367/Bend1.jpg Then pull the remaining longeron until you measure the distances 5 ½” away from the first longeron.
http://i50.photobucket.com/albums/f307/Degan367/Bend3.jpg As you bend the angle, the longerons wants to twist, you can fine tune the twist when you mount the longeron to the firewall.
When the curve and angle are done, you have to cut the notch at the other end of the longerons for the up rights post where the F-711 bulkheads go. Separate the longerons and orient them on your table so you can mark the top.
http://i50.photobucket.com/albums/f307/Degan367/Bend4.jpg You only get one shot at this so mark the top of the longeron where you will cut the notch on each longeron. Use the F-714 Plate notch as a template to mark your longerons. Clamp the F-714 plate to the longerons. Make sure you position the end corner of the F-714 plate per the drawing. Orndorff figure out his measurement was 172 27/32” from the other end. DOUBLE CHECK YOUR OWN MEASUREMENTS. Do not cut the longerons off at the notches, you just have to notch the top and leave the side pieces of the longerons alone.
http://i50.photobucket.com/albums/f307/Degan367/end1.jpg Once the notches are cut, there is a little bit of top longeron sticking past the end corner of the F-714 plate, just trim the top of each longeron and do not cut off the side piece of the longerons.
http://i50.photobucket.com/albums/f307/Degan367/End.jpg
Orndorff really made this a easy process. I strongly suggest you purchase his DVDs since a picture is worth a million words and he shares lots of great information and tips. Use this procedure at your own risk as I cannot be held responsible if you muck it up.