The next time you board an aircraft

A WWII RELATED AEROSPACE POST TO COMMEMORATE D-DAY: 81 YEARS AGO TODAY

I have a homework assignment for you, the next time you board a commercial aircraft: Tap your fingernails on the aircraft skin. Look at how thick it is as you enter the door.

I love to touch aircraft; they are just cool! I love to think about where they have been, and where they will go. That is true for commercial aircraft, and especially true for military that have served us well like the B-17.

The aluminum (or composite) skin of a modern commercial aircraft is about 1mm thick. Or about the thickness of 5 soda cans. The door is a stress point, so it is a bit thicker there, but most of the skin is just 1mm thick. This skin creates a sealed pressure vessel that protects and keeps us comfortable as we cruise through the air at 35,000 feet. The atmosphere just outside your aircraft window is -65°F. The fuselage of your aircraft expands a little at altitude because the pressure inside is much higher than outside. It’s OK, the skin is designed to flex like that every day, several times a day, for decades. It’s the result of some great engineering and design.

There is a museum inside the Pima Air and Space Museum near my home in Tucson, AZ. The museum inside the museum is the 390th Memorial Museum. https://www.390th.org/ This museum tells the story of the 390th Bombardment Group and the B-17 Flying Fortresses that they flew. The 390th operated in Europe in WWII. The centerpiece of the museum is a fully restored B-17 that you can examine up close. I have visited several times, and I am awestruck every time. The skin of that aircraft is about 1mm thick too, but that fuselage was not sealed.

B-17s typically operated at 25 K feet (-30°F), but there were times they operated up to 35 K feet (-65°F). It was -30°F (or colder) outside AND INSIDE that aircraft. Many of the machine gunners lost their fingers to frostbite because gloves cannot protect your hands from metal that is -30°F. I cannot imagine how difficult and painful that was.

I tap my fingers on the fuselage when I visit the museum’s B-17, just like I do when I board a commercial flight. Every time I do, I think about those brave men that endured and even thrived in impossible conditions. The free world owes a debt to those men that we can never repay.

So the next time you enter an aircraft. Tap your fingers on the skin and think about the engineers that designed, and the mechanics that built, the incredible machines that fly you safely to your destination, and be thankful for all the men and women that gave their lives to buy our freedom so we can travel whenever we want.