Chipmunk

And now for something completely different. A few weeks ago I had the pleasure of going for a flight in a de Havilland DHC-1 Chipmunk. I know it isn’t quite connected with the overall topic of this blog, but I had a great time and felt I had to share it… Normal service will resume shortly!

 

From the outside, it’s a very pretty-looking aeroplane. A narrow nose, with a single metal propeller. A single sliding canopy covering two seats. Beautifully shaped wings and the unmistakably de Havilland tail. It’s not a very big aeroplane, and it’s not particularly powerful, but it shaped a generation of British pilots in much the same way as its immediate predecessor, the famed Tiger Moth.

But inside the cockpit, underneath that narrow framed canopy, ‘pretty’ is not the word to describe the DHC-1 Chipmunk. The design dates back to the immediate post-war period in British aviation, and it shows. The concept of ergonomics simply hadn’t been invented yet and many of the controls are tucked into slightly bewildering places around the cockpit. The master switch is positioned on the sidewall, down near your left shin. Sticking out of the floor nearby is the brake lever – pull to activate, then push the appropriate rudder for something approximating differential braking. The mixture control is pulled aft to select fully rich – the exact opposite of more or less every other aeroplane ever built. The throttle lever has a little ball on top (helpfully marked with a “T” in the Tiger Moth fashion) and is mounted with the mixture lever on the left side of the cockpit. The flap lever, with a ratchet to keep it in place, is reached for with a nearly fully-extended right arm and pulled up like a really big handbrake. The designers did away with the need for a complicated mechanism to adjust seat height by simply bolting the seat firmly to the floor. If it’s too low for you, get some cushions. If it’s too high, bad luck!

Priming the engine on VH-AKB, the Chipmunk that I flew recently, is accomplished by the highly technical means of pouring a small amount of fuel into the carburettor intake (the original priming mechanism having long ago given up the ghost). Once settled into the cockpit, the start procedure feels like it needs four arms. You cradle the stick in the crook of your right elbow, while keeping pressure on the brake lever with your right hand. Your left hand cracks the throttle open, then moves across to the starter button which is positioned about as far away from the throttle as it physically can be, high up on the top right-hand corner of the instrument panel. Once the engine fires, that left hand needs to be quick to move to the throttle to ‘juggle’ it and catch the engine before it dies – otherwise you need to unstrap, climb out to reprime the engine, and try again.

Taxiing in this aeroplane is an exercise in coordination. Juggling the throttle and the brake lever with your left hand while holding the stick back with your right (as is essential in any taildragger), weaving down the taxiway to see past the nose and trying not to hit anything is quite difficult. Slow and steady is the answer. Hopefully you’ll manage not to bend the aeroplane before taking off.

But get the aeroplane in the air and all the niggles involved in its ground handling simply disappear. The controls are beautifully light – ailerons especially so. A standard turn requires very little control movement. Even an aileron roll can be flown with much less stick than I was expecting. Aerobatics are graceful in a Chipmunk. Sure, there are many more capable aerobatic aeroplanes out there. But not many have the combination of finely balanced ailerons, responsive elevators and sheer old-world charm that this one does. She loops, rolls, stalls, wings over and generally has a whale of a time. And that all-over canopy gives a beautiful view of the ground when you’re upside down.

Back to the airport, then, to see if modern-day spamcan pilots like me can land a Chipmunk. Like the Tiger Moth, this machine likes the ‘wheeler’ style of landing, with a trickle of power on, because the oleos soak up any excess sink rate on touchdown. The actual touchdown is relatively easy to judge. But the problems start once the aeroplane slows up and the tailwheel came down. The rudder is extremely light and it’s very easy to overcontrol, leading to some not particularly dignified swerving down the runway if you’re not careful. The second attempt – once you tell your feet to wake up on the rudder bars – is usually much neater. But slow down to taxi speed and once again you need to juggle that awkward but very British brake system to get back to the hangar. It’s almost like the aeroplane doesn’t want to stay on the ground, like it’s trying to convince you that up in the air is where it belongs.

One thing that Gypsy Majors like is oil. After some aerobatics, the engine bay of the Chipmunk certainly shows why:

Apparently that’s normal. Like all good vintage aero engines, if it stops dripping oil, it simply means it’s run out.

Despite her awkwardness on the ground, there’s no doubt that these aeroplanes have a certain ‘class’ that modern-day aircraft just don’t have. The heritage of the Chipmunk, stretching back to the Tiger Moth days, is certainly evident. Many pilots learnt to fly on aeroplanes just like this one in the 1950s and 1960s, and it’s great to try and capture some of that era of flying if you ever get the chance.

   

(c) 2010 Adam Purcell