"Everyman's Jet Engine" - Why Valveless Pulsejets?
For the pulsejet hobbyist, there is practically never any reason to go to exotic materials for
engine construction. For beginner engines, and for low-cost prototyping of new experimental designs,
nothing beats ordinary mild steel (unless there are weight concerns for some reason). The most
expensive material 99 percent of hobbyists will ever need to use will be ordinary stainless steels
(e.g. Type 304, Type 308, Type 316 alloys) which are readily available and not outlandishly priced,
and can be bought in small quantities and in many different sheet thicknesses and bar sizes.
- Built without any use of exotic materials
There are two main advantages to stainless alloys: First, they are absolutely permanent, so you're
building an engine that will literally "last a lifetime"; second, they are much stronger at red hot
temperatures than any mild steel, so a much smaller sheet thickness can be used, thus providing much
lighter weight for the finished engine. Note, however, that stainless requires better tooling and much
higher levels of skill to work with, especially in the welding of your engine.