A word of caution, if I may, to anyone who hopes to use drawings and/or other information supplied by J. Houston Maupin. Though some of his material may be valid, I've found no evidence that he actually fabricated and successfully operated all his designs. I tried many times to contact him in Tipp City (I live 20 miles NW of there,) but other area Maupins deny knowing him and the local BBB has no information.
The "jet bike" in his ad was the creation of people at Aeromarine Co. in (about,) 1948; Maupin was not involved in any way and his literature did not show much about its D5-1 pulsejets. That engine employed 5 modified D-J valve head assemblies and developed 30-35 lbs. static thrust.
Louder is always better.