"Everyman's Jet Engine" - Why Valveless Pulsejets?
The total absence of internal moving parts means there are no sliding surfaces (i.e. "bearing surfaces")
that require precision machining. Of course, it's true that most builders will want to mount a spark plug
for engine starting; but for this, a steel or stainless nut matching the desired spark plug's thread can
be used, by simply welding the nut onto a hole in the combustion chamber. A similar technique can be used
in most cases to locate a fuel nozzle (or its mounting). While an engine must be built with reasonable
"shop rule" accuracy, the demands of high precision machining are completely unnecessary.
- Built without machining of any kind