Why Aspect Ratio doesn’t Matter

In the ever-present drive to improve the efficiency of aircraft, “higher aspect ratio wings” are frequently named as one of the reasons that new aircraft are more efficient than previous generations. Here are a couple of examples: “… carbon fiber allowed designers to produce a higher-aspect-ratio wing for lower drag…” (Aviation Week, May 2015) “… wings with high aspect ratio generate the lowest lift-induced drag…” (Flight International, April 2006) “A higher aspect ratio wing has a lower drag…” (NASA, May 2015) Indeed there seems to be a general consensus that higher aspect ratio wings are more efficient. This is however misleading, since Continue Reading

How will Aircraft be Made in the Future?

At the end of the second world war, cars and aircraft were manufactured in almost the same way; a slow moving production line where skilled workers more or less assembled the vehicles by hand. Since then the automotive industry has become far more automated and has scaled enormously. Robotic production lines produce millions of cars every year. Comparing the two assembly line photos below, taken more than 50 years apart, it can be seem that during this time the aerospace world has barely changed. Even with the planned rates of 50-60 per month for the Airbus A320 family and Boeing 737 family, Continue Reading

Airbus A340: Making the Same Mistake Twice

It is possible to hide an aircraft in plain sight. Ask most people how many four engined aircraft Airbus has produced and the typical answer is two; the A340 and the A380. The correct answer is three, the differences between the A340-200/300 and A340-500/600 are such that they are by any standards different aircraft, despite similar appearances. Compared to the baseline A340-200/300, the A340-500/600 has: Newer, larger, heavier, more efficient and more powerful engines from a different supplier. A new wing of increased span, sweep and area. Enlarged vertical and horizontal tailplanes. Modified landing gear with extra wheels. Fuselage lengthened Continue Reading

Why Aren’t Planes Made from Steel?

Steel is a wonderful metal that has become ubiquitous in the modern world. Ships, trains and cars are made from steel, yet the vast majority of aircraft are built from aluminium, although carbon fibre is becoming more popular and wood was used extensively through to the end of the Second World War. Is there Anything Wrong with Aluminium? Although not inherently unsuitable for building aircraft, aluminium does have a long list of disadvantages as a building material compared to steel. It is: More expensive More susceptible to corrosion Difficult to weld More susceptible to fatigue Quicker to melt Not as strong Continue Reading

The Airbus Widebody Fuselage Cross-Section

Although the Airbus A300 is no longer in production, part of it lives on. The original fuselage cross-section of the A300 has been used on a further 13 Airbus aircraft across 3 different aircraft families, ranging in length from 47m (155ft) all the way up to 75m (246ft). As of today 2427 aircraft using the same A300 cross-section have been delivered, even though only 561 A300s were constructed. This year the same cross-section will have enjoyed 42 years of uninterrupted production, and a backlog of 363 orders for the A330neo will ensure production past 2020 at least. A perfectly circular Continue Reading