I've been building an RC model of a German WWI Albatros fighter. I just can't do that without also doing research about it, and the Albatros used a Mercedes SOHC6 engine.
I found a web site (in New Zealand) from a company the restores and manufactures vintage aircraft. They made a flying replica of an Albatros, with the primary intent of building it the way it was back in the 1900s.
Here are some excerpts from the excellent web site:
http://thevintageaviator.co.nz , which some of you might enjoy (and I encourage) perusing.
Engine Starting Process (completed by ground crew)
Turn ignition switch to Off
Retard Ignition
Throttle closed
Decompression lever to De-compress (lever pointing down)
Hand rotate the propeller 6 revolutions. This will draw a fresh fuel mixture charge into each cylinder
Close de-compression lever
Magneto switch to M1 (start)
Rapidly turn the Hand Start Magneto - Engine will fire
Idle at 200-250 rpm for 5 to 10 minutes
Slowly increase revolutions to 600 rpm
Magneto switch to M2 and check for rpm drop (magneto check)
Magneto switch to 2 and move ignition advance lever to mid position
When running cleanly, fully advance ignition and check full throttle against rpm reading
When engine checks are complete, idle at 300 – 350 rpm until the pilot is in the airplaneThey also have a flight report of their Albatros, with some detail of what it is like to operate the aircraft in modern times. Here are some excerpts, but their site is far better for the experience:
http://thevintageaviator.co.nz/projects/aircraft/albatros-dva/notes-flying-d-vaPre-flight
So - getting ready to fly it! First it must be serviced. Fill the cooling system with water, 27 litres of it. It must be drained each night because there is no proper seal between the water in the water pump and the engine oil. The water pump sits at the bottom of the engine crankcase and the water pump drive shaft is lubricated and sealed by grease under pressure from a greaser mounted in the cockpit. This pressurized grease forms the barrier between coolant liquid and oil in the engine's sump. The pilot must twist the greaser handle every so often in flight to make sure these two fluids are kept separated.
After servicing with water one of the cowls is removed to service the two fuel tanks. It is imperative to visually check the fuel level since the gauge isn't very accurate and there is no indicator fitted to the emergency tank, which drains down into the main tank over time. If this happens the air system tends to become filled with fuel - a condition which makes the engine-driven air pump look like a Greek fountain! Filling the cockpit with fuel or if left unnoticed spraying the engine and pilot with fuel just as the engine springs to life!
The next step is to "decompress" the engine by moving a lever that reduces the engine compression for starting. Then the cowlings can be put back on and the engine started. The booster magneto is sufficient to start the engine without even hand swinging the prop on most occasions. The coolant warms slowly even with the radiator shutters closed and the engine only runs well when warm so proper temperature is critical.
“oil and grease... will be thrown in your face”
As the engine warms up the pilot has plenty of time to contemplate the flight and what to look for; mind the airspeed don't pull to many G's watch the temperature, twist the greaser, keep the air pressure up. and if all the oddities aren't enough to keep you busy, you can watch the engine in operation, without a firewall the engine is in plain sight just ahead of the pilot below the guns. The overhead cam has an exposed valve mechanism which is fascinating to watch, you can see the valves, springs and rockers all moving, dripping with oil and grease which inevitably will be thrown in your face throughout the flight, making goggles a must have. It's a machine that offers all of the senses a little something; just as it starts cold water splashes in your face as the upper wing radiator leaks water into the cockpit a little later on the taxi to take off this will be near scalding water that is dribbling out of the radiator.There's more for those interested, as well as plenty of good pictures. I still haven't explored it all. It will likely keep me occupied for days. It's very well done and fascinating.
