So the gas powered kind were single tone and the electric were dual? Or did I misread your post?SuperBanshee wrote:No - all Mobil Directos were shipped out as 8 port (BN44-G) or 10-12 port (BN44-E). The four rotor blades are pressed in place during manufacturing. It is possible that a different set of blades were temporarily used, however every example I've documented used the standard four blades. The blades draw in air - while many sirens have the blades positioned to align with the rotor ports, this is not always the case. Blades that cross over any of the port openings will give a warbling tremolo effect, as noted in my first post.
I think so. Not exactly sure though. Here is a link of the video.coastalsyrolover wrote:So the gas powered kind were single tone and the electric were dual? Or did I misread your post?SuperBanshee wrote:No - all Mobil Directos were shipped out as 8 port (BN44-G) or 10-12 port (BN44-E). The four rotor blades are pressed in place during manufacturing. It is possible that a different set of blades were temporarily used, however every example I've documented used the standard four blades. The blades draw in air - while many sirens have the blades positioned to align with the rotor ports, this is not always the case. Blades that cross over any of the port openings will give a warbling tremolo effect, as noted in my first post.
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