The mighty BAE – RJ

Why am I presenting this rather stumpy, odd-looking airplane to you? It's not exactly a state-of-the-art fighter jet, nor is it as impressive as an Airbus 380, or as sleek as a Global Express... but this airplane is pretty cool, and let me tell you the reasons why.

Reason 1: It is the first commercial jet aircraft I flew in as a passenger, and the first commercial jet aircraft I flew as a pilot (ok, that's probably only interesting to me)

Reason 2: But it is also the aircraft in which the Queen of England flies

Reason 3: It is British built - the original variant being the BAe 146 (British Aerospace), and is the most successful British civil jet airliner ever produced

Reason 4: It is designed for landing on short, mountain runways and has some really cool features. 

Different Design, Different Looks

The BAe 146 (or its newer version the AVRO RJ) is not your standard-looking commercial jet aircraft. It had its first flight in 1981 and started service in 1983. Designed to fill a gap in the civil airliner market and aimed to serve short-haul regional routes, a total of 387 of them were produced. However, I am not here to give you a history lesson. I want to tell you about its features because, as I already said, it is a good airplane to study because of its design differences.

The Following is a Technically Accurate Picture of a BAe 146:

First up, the engines.

There are 4 of them. The turbofan engines are mounted underneath the high wing, this means the wing has an uninterrupted upper surface. Being higher off the ground, it also mean the aircraft is less limited with bank available on landing (useful in crosswinds), and less likely to ingest foreign objects which could cause damage (FOD), a useful feature to have on rough airstrips.

The engines are not particularly powerful individually (just under 7000lbs of thrust per engine), but the performance and redundancy of having four means it is better equipped again for those fearsome mountain strips and high elevation airfields. These engines were based on engines used to power Chinook helicopters. The design of the engines resulted in the airplane's nickname "Whisper Jet" because they are particularly quiet compared to other jet engines.

Now, Onto the Wings

I already mentioned the high wing positioning, but they are also anhedral (slant downwards). This is because the overall design of the aircraft, and especially the high wing position, makes them too stable. So, downward sloping wings (similar to what you see on fighter aircraft) increases the roll performance and maneuverability - another point of interest for those of you studying aerodynamics. The wings have full- length spoilers which help it to dump lift and stop better, and they have big flaps that can extend out to 33 degrees. 

The movement of the flaps from around 10 degrees to its first stage - 18 degrees - causes quite an aerodynamic disruption because of the mechanism that shifts to extend them, and the gap that forms between the flap inside edge and the fuselage. This results in a sound referred to as a "flap hoot" (more of a bizarre roaring noise that often startles passengers into thinking an engine is giving out). The high "T" tail design keeps the elevators out of the disrupted airflow from the wings and fuselage, creating better pitch control better. However, should the aircraft be placed in a deep stall, where the elevator loses authority, the stall recovery is much more difficult.

Next, the Brakes

Now, you will see I have labeled "Airbrake" on the picture. That’s because the Avro RJ is equipped with a cool tail section that opens up like a big clamshell to create a lot of drag. This allows the aircraft to fly steep approaches (like the 5.5degree one into London City), and to do great short field landings. It is also fun to "flash" it at any aircraft that is behind you while you taxi.

This aircraft was second only to Concorde in having carbon brakes fitted. These are pretty standard now on airliners because they are much more efficient and good at stopping heavy tubes thundering down runways. But the carbon brakes combined with the airbrake on the RJ85 again added to its ability to go into shorter runways where it needed better stopping performance. They also meant the aircraft did not really need thrust reversers on the engines, which makes their design simpler, and with fewer parts to fail.

Don’t Forget the Undercarriage

If you watch a "standard" jet landing you will notice the wheel bogies "hang" a little differently to those on an RJ. This is because it has trailing link undercarriage. Simply put, these are more robust (especially since these were extra toughened to resist damage). As the aircraft lands, the upward energy of the airplane touching down is dissipated through the undercarriage and its big oleo suspension making for generally smoothing feeling landings (nicer for passengers, and better for the pilot who can show off after their smooth "greaser" of a landing).

And Finally, its Speed and Range

The Avro RJ can seat around 100 passengers depending on the variant. It is a fairly stumpy aircraft measuring in at around 30 m (98.4 feet), with a wingspan of just 26.34 m (86.4 feet). The MTOW of the RJ85 is 42,184 Kg (92,999 Pounds) and it can carry up to around 12,000 L fuel giving it a range of around 1,970 nm. The aircraft has a max speed (VMO, MMO) of 300 kts/ Mach 0.72 (so wouldn't be winning many races), and a max altitude of 35,000', and a landing distance of around 1,200 m (3,937 feet).

So there you have it, some interesting technical information on the BAE146 to demonstrate how not all airplanes are the same. It might not be the sleekest, slenderest of aircraft, but it is fun to fly, robust, and has had a very successful life in civil aviation and deserves a moment of appreciation.