1945 training film shows how to repair the chrome molybdenum steel structural tubing on a Piper Cub aircraft. Produced by Jam Handy.
Originally a public domain film from the US Office of Education, slightly cropped to remove uneven edges, with the aspect ratio corrected, and one-pass brightness-contrast-color correction & mild video noise reduction applied.
The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original).
Wikipedia license: http://creativecommons.org/licenses/by-sa/3.0/
A hollow structural section (HSS) is a type of metal profile with a hollow tubular cross section. The term is used predominantly in USA, or other countries which follow US construction or engineering terminology.
HSS members can be circular, square, or rectangular sections, although other shapes are available, such as elliptical. HSS is only composed of structural steel per code.
HSS is sometimes mistakenly referenced as hollow structural steel. Rectangular and square HSS are also commonly called tube steel or structural tubing. Circular HSS are sometimes mistakenly called steel pipe though true steel pipe is actually dimensioned and classed differently from HSS. (HSS dimensions are based on exterior dimensions of the profile, while pipes are essentially dimensioned based on interior diameters, as needed to calculate areas for flow of liquids.) The corners of HSS are heavily rounded, having a radius which is approximately twice the wall thickness. The wall thickness is uniform around the section.
In the UK, or other countries which follow British construction or engineering terminology, the term HSS is not used. Rather, the three basic shapes are referenced as CHS, SHS, and RHS, being circular, square, and rectangular hollow sections. Typically, these designations will also relate to metric sizes, thus the dimensions and tolerances differ slightly from HSS...
41xx steel is a family of SAE steel grades, as specified by the Society of Automotive Engineers (SAE). Alloying elements include chromium and molybdenum, and as a result these materials are often informally referred to as chromoly steel (common variant stylings include chrome-moly, cro-moly, CrMo, CRMO, CR-MOLY, and similar). They have an excellent strength to weight ratio and are considerably stronger and harder than standard 1020 steel, but are not easily welded (need pre and post weld thermal treatment to avoid cold cracking).
While these grades of steel do contain chromium, it is not in great enough quantities to provide the corrosion resistance found in stainless steel.
Examples of applications for 4130, 4140 and 4145 include structural tubing, bicycle frames, tubes for transportation of pressurized gases, firearm parts, clutch and flywheel components, and roll cages. 4150 stands out as being one of the steels accepted for use in M16 rifle and M4 carbine barrels by the United States military. These steels are also used in aircraft parts and therefore 41xx grade structural tubing is sometimes referred to as "aircraft tubing"...
The Piper J-3 Cub is an American light aircraft that was built between 1937 and 1947 by Piper Aircraft. The aircraft has a simple, lightweight design which gives it good low-speed handling properties and short-field performance. The Cub is one of the best known light aircraft of all time. The Cub's simplicity, affordability and popularity — as well as its large production numbers, with nearly 20,000 built in the United States — invokes comparisons to the Ford Model T automobile.
The Cub was originally intended as a trainer and had great popularity in this role and as a general aviation aircraft. Due to its performance, it was well suited a variety of military uses such as reconnaissance, liaison and ground control. It was produced in large numbers during World War II as the L-4 Grasshopper. Large numbers of Cubs are still flying today. Notably, Cubs are highly prized as bush aircraft.
The Cub is a high-wing, strut-braced monoplane with a large-area rectangular wing. It is powered by an air-cooled piston engine driving a fixed-pitch propeller. Its fuselage is a welded steel frame covered in fabric, seating two people in tandem.
The aircraft's standard chrome yellow paint has come to be known as "Cub Yellow" or "Lock Haven Yellow"...