Raising a ceiling on a trussed ceiling

The trusses are dark... I am not quite sure why. The pic actually looks real nice... Whereas in real life... Not so nice.

To Awing- thanks! So if I understand... I would need a new ridge beam? What is up there is a 2x4 if I recall.

As best I can tell.. The house was built in the 30-40s and then in 1990 someone re-informed it... See next pic. Note the original vertical studs in dark brown and the horizontal studs installed in the 1990s. At that time, I guess they added the strapping and sheet rocked the ceiling. Do you think it would be ok for me to remove the strapping? Or maybe put some strapping on the other side of the 20' cross member? Maybe 3-4 rows of strapping versus every 16".

If I understand... The 20' cross member rests right on the walls... So the walls are carrying the weight of the roof... And the 45s just provide some deflection onto the 20' cross member that carries the weight. I assume the new ridge beam would carry the opposing weight of the rafters on either side of the roof transferring down to the walls then?

What you have certainly looks like site fabricated trusses. A truss is a structural element comprised of triangles. The individual pieces of the truss are considered pinned together where they join. Modern wood trusses are fabricated using gang nail plates, but older trusses were fabricated using plywood plates, and even older trusses, like the ones you seem to have, were fabricated by nailing the pieces together. Nothing wrong with that type of construction.

Simple trusses such as the ones you seem to have are only supported on the ends. The trusses exert vertical load only on the walls, no horizontal load. The individual truss pieces are either in tension or compression, but not bending. There are NO roof rafters in a truss, what you are calling a roof rafter is the top chord of the truss. A roof rafter in a stick built house has a combination of compression loading and bending, which is completely different than the top chord of a truss, which is in compression only, except under unusual loading circumstances such as wind uplift, when the top chord could go into tension, but never bending.

Trusses do not need ridge beam or collar ties, they just need to be supported laterally during construction so they don't fall over. Once the sheathing is installed, and the trusses are connected to the walls, the trusses are not going anywhere.

Raising the ceiling in a truss roof house is not a simple matter. You need to modify the trusses, which requires you to perform an analysis of the loading on the new truss system you plan to create. This is usually not a DIY exercise, it may be something a local engineer or architect could help with. If you do not understand the mechanics of a truss system, I strongly suggest you NOT modify the trusses yourself, unfortunate results can occur, including collapse of the roof.