Hi MATTY
Just a few points to add to" Inbalance"`s comments. The engin does not have a conventional throttle, rather you have two levers, one for air, one for fuel, but they must be used together.
The engine is started by pumping air pressure into the fuel tank,so it will flow to the engine when the fuel lever is opened, via a needle valve. Each cylinder is then primed individually( or "doped",as it was called),by hand-turning the prop.
there are two magnetos, one is the starting mag. which is hand-cranked by the pilot when the engineer(s) call" contact," and after they have released the blades.The other mag is switched on at the contact call.If you get the sequence wrong, there is a good chance the engine may fire and clobber the prop swinger---If so you may well be relieved of your command!
The air valve may have been opened slightly at the start; hopefully everything will burst into life,on the prime so to speak. It now requires the pilot to pick-up the engine on the fuel and air levers to get it to run smoothly,and stop winding the starter mag.,pump a little more air pressure into the fuel tank as it is normally supplied by a small wind -driven pump in flight!
The engine wil not normally idle well, so after the usual check on fuel pressure and oil, the run-up is done by opening the air lever,followed by the fuel valve until max rpm and smooth running are achieved-again by small variations in the air and fuel valves. It is handy at this point to mark the levers positions on the quadrant with a china graph, as you need this position for t/o. Now one can check low speed running by now closing the fuel valve first,followed by the air lever.
The reasons for operating the levers in this order is that it is better to have an engine which has more air in the system than excess fuel, as it will flood, and will not respond at all until all the fuel has been blown-thru`-- in flight the a/c leaves a black trail of smoke.
As the levers are closed towards shutoff a position is reached where the engine will idle ok .Mark this position as well. the magneto cut-out,a push-button on the control-column can now be pressed to allow the engine to run-down to lower revs, for taxiing,and released briefly to stop it from stopping.
Assuming all is well you now taxi out doing all the t/o checks as you go, line-up and open the levers to the previously noted settings, remembering that there is a lot of gyroscopic energy in front, requiring a lot of fancy footwork to keep it straight, balanced etc------- and so far we`ve only just got airborne!!
In flight the levers can be used together in the same manner as normal throttle control to set a cruise or low power for descent, as long as one remembers to always have more air than fuel when changing conditions-- A lot written- even longer than some of my flights!
