The Siren Board

Zarlog wrote:

EOWS1212man wrote:

coastalsyrolover wrote:They are positive displacement blowers. They move the air a certain way (IIRC) which is why a centrifugal based blower (like say... A leaf blower?) of the same specs makes such a cruddy blower.

Yup. Instead of using an impeller like most conventional blowers, the thunderbolt "roots style" blowers use lobed rotors to create pressure. I am interested to see what would happen if you were to stick a finger or two into one of these things...



https://www.youtube.com/watch?v=_-fwWrFLiyY


https://www.youtube.com/watch?v=ZifVA3jWhno

How exactly does that move nearly enough air to supercharge the siren? I can see it working great with water but with air it would be like using a huge metal ingot as a fan blade.

I'm sure an expert could explain this better... But a very very very veeeeery basic explanation is sort of like this: when a leaf blower or carpet blower blow, it's kind of like it's sending a concentrated amount through... a positive displacement blower on the other hand has a wider, more open channel to put more air through and "displaces" it differently... I think?

Centrifugal blowers move air, they don't compress it and create positive pressure in the way you would need it to for a Thunderbolt. Roots superchargers move air, compress it and create positive pressure you need to supercharge whatever it is you're supercharging. You would need a HUGE blower wheel, spinning really fast to create even close to the kind of pressure you want. It's dependent on the amount of air being moved and blade design with a centrifugal blower. The reason a roots blower can supercharge a Thunderbolt is because that air is under a lot of pressure, around 10psi, so 250 cubic feet per minute of air under 10 pounds of pressure for every square inch of space(for a 4M blower) in the pipe and siren. And since the Thunderbolt only has one port(one split port for dual tone), the air the chopper can move is limited.

EOWS1212man wrote: Yup. Instead of using an impeller like most conventional blowers, the thunderbolt "roots style" blowers use lobed rotors to create pressure. I am interested to see what would happen if you were to stick a finger or two into one of these things...

Let's just say that there would be pulp and blood spewing out of the other end... :sick: