Building a pulsejet

This is a video of the engine in a "lockwood-hiller" configuration, the main advantage of which being that both of the ports of the engine face the same direction. Essentially, the engine has a large amount of blowback out the intake due to the lack of moving parts and the reliance on aerodynamic valving for the engine cycle, and the only way to recoup that lost power is to make both ends of the engine face the same direction. Additionally, you can make either the intake or the exhaust bend to achieve this.

  The most difficult part of building a pulsejet is finding the exact geometry the engine needs to have to be able to cycle. According to a well known pulsejet designer who goes by the alias "PyroJoe", you base all the engine dimensions of the exhaust diameter. For example, if the engine has a 1 inch diameter exhaust, the length of the exhaust should be 20 times that diameter, the combustion chamber should be twice that in diameter, and about four times that in length. The intake should be 0.75 times that diameter and about 2.5 times that in length. Furthermore, there are parameters for making an expansion chamber exhaust such as maintaining a roughly 9 degree angle of cone expansion for optimal performance.

In this engine I couldn't follow the optimal expansion angle of 9 degrees due to the use of bell reducers to achieve the increase in exhaust diameter.