ORIGINAL: Sport_Pilot
Actually model Diesel engines are not Diesels. To be a Diesel engine, it must operate at a constant pressure during the power stroke. To do that you must inject fuel into the engine at a constant rate during the power stroke. I am interested in model Diesel's as an interesting power plant even if not a true Diesel. But the cost of fuel puts me off. If they ran cheap fuel oil I would buy one right away.
Seems some one posted a one off true Diesel engine a while back.
It is nice to see you attending this forum, Hugh.
Fuel cost is not a fixed number.
As you already know, a model Diesel engine will put out about the same HP as its glow counterpart, at significantly lower RPM, while using about 40% less fuel. Also, with a Diesel, you don't need to invest in glow-plugs, glow-drivers and once you have mastered a good starting procedure, no electric starter (this doesn't go for me; I don't use it for glow engines either...).
Check these out!
MVVS .49 Diesel (an AJC head), normal silencer; Bolly 12.5x6 prop @ 10,300 RPM - 1.04 HP.
OS.46FX glow, normal, un-baffled silencer; APC 10x6 prop @ 14,300 RPM - 1.04 HP.
The exact same HP, yet the Diesel uses half as much fuel; 6 ounces of fuel last nearly 15 minutes at full throttle.
Can you say the same about the OS glow engine?
While the definition of a Diesel engine may say what you wrote; Rudolf Diesel's engines did not comply with them.
It also says, BTW, that a Diesel engine has no throttle...