Robin HR100/210 G-BAPY

In August 2006, I became a part owner of G-BAPY, a 1973 Robin HR100/210 “Safari”. This page contains a description of the aircraft and its systems.

This page is currently under construction.

What is G-BAPY?

G-BAPY is a four-seat, single-engine aircraft made by Robin, the best known French manufacturer of light aircraft. Unlike other Robins whose wings are constructed from a fabric-covered wooden framework, the HR100 is an all-metal aircraft. She was built in 1973, and is one of only about fifteen Robin HR100 aircraft on the UK register.

Under the cowling, G-BAPY has a 210 horsepower Continental IO-360 engine. This is a six-cylinder, horizontally opposed piston engine with fuel injection, manufactured under licence by Rolls-Royce. Attached to this is a two-bladed constant speed propeller.

G-BAPY is a terrific combination of speed and economy. At a modest 65% power, she cruises at 125 knots (indicated) and burns about 10 US gallons per hour. In still air, this equates to about 17 miles per gallon (imperial). That fuel economy might not sound very impressive compared to modern cars that are capable of over 50 mpg, but how many cars would actually achieve 17 mpg when driven at 145 mph? None, I'd wager!

Part of this efficiency comes from the design of the airframe. It may be a terrible aviation cliché, but G-BAPY is a "slippery" aircraft. The undercarriage has close-fitting spats and the gear legs are neatly faired. The fuselage and wing skins have no protruding rivets and the fuel caps are hidden behind flush-fitting access panels. The overall effect of these details is that the aircraft has much less drag than many other light aircraft - a fact that reveals itself most noticeably when you try to slow it down.

The fuel system

Endurance - the ability to fly for a long time before running out of fuel - is a particular strength of this aeroplane. She has four fuel tanks: two in each wing. These are of the rubber bladder type and each hold 25 imperial gallons, giving the aircraft a total fuel capacity of about 450 litres. The endurance is therefore a comfortable 10 hours - although whether "comfortable" is the right word to use for that length of time in a light aircraft is a debatable point. It is certainly true that the fuel endurance of this aircraft exceeds most people's bladder endurance!

The fuel system is slightly more complex than the Cessna 172 that I've been used to up to now. Fuel management in the 172 is easy. The 172's fuel cock has four positions: left, right, both and off. In normal flight you simply switch to "both" and let gravity take the fuel from the wings to the engine. In the Robin, the fuel can only be fed from one of the tanks at a time, with a fuel cock that has five positions: inner-left, inner-right, outer-left, outer-right, and off. There is a slight peculiarity though, in that the return of excess fuel that doesn't get injected into the engine always returns to the inner left tank, regardless of which tank is currently selected. If that tank is full, therefore, you must burn fuel from that tank first, otherwise it will overflow. It is also a bit odd when burning from one of the other tanks to see the inner left tank gradually filling up!

Cabin interior and equipment

Access to the interior is via a sliding canopy instead of the conventional doors of the Cessna 172. Undoubtedly this makes it slightly harder to get in and out (the fact that there's no footstep to assist the awkward step up onto the wing is a pity), but it also greatly improves the overall visibility from the cockpit. In particular, the lack of an "A" pillar improves the diagonal view, and the low-wing design improves the upward visibility (compared to the high-wing Cessnas that I'm more accustomed to).