3
instrument panel. This knob, labelled “ALTERNATE AIR”, should be pulled out if significant
airframe icing happens to be encountered during flight
.
No fuel priming is required for engine start
and furthermore, as we will see, there is no mixture
control to be taken into consideration.
Perhaps the most interesting part is the fact that the required fuel is diesel (DIN
2
EN590), which may
be obtained at any car station-service and which is considerably cheaper than the usual aviation
gasoline. It is unfortunate that, at least presently, few airports (if any) are equipped to provide diesel
fuel. However, as said previously, the TAE 125-01 operates equally well on Jet A1 fuel (ASTM
3
1655),
which is normally available at any major or regional airport. On the other hand,
assuming that
diesel fuel would ever be used, one must remember that the fuel temperature in the tank
must be closely monitored, before takeoff as well as during flight to avoid formation of
paraffin
(see below).
At any rate,
keep in mind that whenever a refuelling stop is required elsewhere than at the
home base, make sure that you don’t plan a stop at an airfield where these fuel types are
not available!
THE TAE 125-01 ENGINE AND ITS PROPELLER
Although most light aircraft engines feature four or six horizontally opposed cylinders, the TAE 125-
01, also referred to as the CENTURION 1.7, has four cylinders in line with double overhead camshaft
(DOHC). In fact, the engine is based on the Mercedes Series A automotive design.
Another major difference is that, unlike most light aircraft engines which are air-cooled, the TAE 125-
01 is liquid-cooled. This, in turn, results in a significant change, not only in the engine’s cooling
system, but in the cabin heating system as well (see below). The power plant also includes a
turbocharger.
Let us first clarify the term “double overhead camshaft”, and have a few words about the
turbocharger:
Double overhead camshaft
Without digging in the constructional details of engines, recall that each cylinder is fitted with (at
least) two valves: the inlet valve and the exhaust valve. Incidentally, the
TAE 125-01 features four valves per cylinder: two for the inlet, two for the exhaust. The four valve
configuration contributes amongst other things to a lesser fuel consumption and to an improved
quality of the exhaust gases. All these valves are driven by cams (NL: nokken) located on a shaft, the
so-called camshaft (NL: nokkenas) which is itself driven by the crankshaft (NL: krukas).
The camshaft can be located either in the lower part of the engine, close to the crankshaft (NL:
onderliggende nokkenas), or higher up, close to the cylinder head, in which case one talks about an
overhead camshaft (NL: bovenliggende nokkenas), or OHC, operating all inlet and exhaust valves in
the required sequence. Double overhead camshaft, or DOHC, means that two overhead camshafts are
used: one which operates all inlet valves and one which operates all exhaust valves.
Turbocharger
A turbocharger is in fact a form of supercharger and has the very same purpose, namely to increase
the amount of air flowing in the induction system, thus increasing the manifold air pressure (MAP),
and consequently the total power output of the engine. Note that with the TAE 125-01 installed, the
2
:
Deutsche Industrie Norm
3
:
American Society for Testing and Materials
Versie oktober 07
