Thunderbolt 1003A help and pictures.

[QuantumCurse]

I toyed with the idea of seeing if I could get one machined but I don't have a picture of one. If anyone does post it here and I'll see what I could do.

Here are a couple of pictures from before I reassembled mine.
4-5 Port Chopper.jpg
4-5 Chopper 2.JPG

The 4 port chopper is on the bottom? I always assumed it would be on the top.

[TboltTX1]

The 4 port chopper is on the bottom? I always assumed it would be on the top.

Yep, the four port row is on the bottom on mine. I've not seen any other 4/5s close up to know for sure if that was consistent throughout production, I'd imagine it was though.

[QuantumCurse]

The 4 port chopper is on the bottom? I always assumed it would be on the top.

Yep, the four port row is on the bottom on mine. I've not seen any other 4/5s close up to know for sure if that was consistent throughout production, I'd imagine it was though.

Interesting. Thanks for the pictures.

[connerdstines]

They were all like that. That's why the B flat(on chopper level 5) of the four port row is the most audible when you listen to a 4/5 Thunderbolt.

[QuantumCurse]

They were all like that. That's why the B flat(on chopper level 5) of the four port row is the most audible when you listen to a 4/5 Thunderbolt.

Interesting. Does that mean the 4 port tone is more dominant in the pitch?

[connerdstines]

They were all like that. That's why the B flat(on chopper level 5) of the four port row is the most audible when you listen to a 4/5 Thunderbolt.

Interesting. Does that mean the 4 port tone is more dominant in the pitch?

Yes, because it receives more air coming into the rotor since the four port side faces the siren's intake. Same with naturally aspirated sirens too, for example you will hear the 12 port side of a 9/12 ACA siren slightly louder than the 9 port side, since these have the 12 port side on the same side as the siren's intake, and that side therefore receives the most air. This is reversed on Federal 9/12 sirens, where the 9 port side is dominant, because it's on the same side as the intake. If you listen to a Model 2T, it's the same 4/5 rotor, but both sides are open and take in roughly the same amount of air, so neither note is really as dominant as it would be if the intake was restricted to one side.

[QuantumCurse]

They were all like that. That's why the B flat(on chopper level 5) of the four port row is the most audible when you listen to a 4/5 Thunderbolt.

Interesting. Does that mean the 4 port tone is more dominant in the pitch?

Yes, because it receives more air coming into the rotor since the four port side faces the siren's intake. Same with naturally aspirated sirens too, for example you will hear the 12 port side of a 9/12 ACA siren slightly louder than the 9 port side, since these have the 12 port side on the same side as the siren's intake, and that side therefore receives the most air. This is reversed on Federal 9/12 sirens, where the 9 port side is dominant, because it's on the same side as the intake. If you listen to a Model 2T, it's the same 4/5 rotor, but both sides are open and take in roughly the same amount of air, so neither note is really as dominant as it would be if the intake was restricted to one side.

IIRC the reason the ACA Hurricane has the dominate undertone is because more air comes from the blower. Is this the same on the Thunderbolt?

[connerdstines]

Interesting. Does that mean the 4 port tone is more dominant in the pitch?

Yes, because it receives more air coming into the rotor since the four port side faces the siren's intake. Same with naturally aspirated sirens too, for example you will hear the 12 port side of a 9/12 ACA siren slightly louder than the 9 port side, since these have the 12 port side on the same side as the siren's intake, and that side therefore receives the most air. This is reversed on Federal 9/12 sirens, where the 9 port side is dominant, because it's on the same side as the intake. If you listen to a Model 2T, it's the same 4/5 rotor, but both sides are open and take in roughly the same amount of air, so neither note is really as dominant as it would be if the intake was restricted to one side.

IIRC the reason the ACA Hurricane has the dominate undertone is because more air comes from the blower. Is this the same on the Thunderbolt?

Same reason i described. Hurricane's had the 8 port rotor on the bottom side of the motor, which is the side air comes in from the blower. Most of the air left the siren through the bottom rotor and significantly less left through the top, which was the 10 port rotor(there were different ratios made, but all the ones known to exist were 8/10) due to the distance between the two, making it much quieter than the 8 port rotor. This affects the Thunderbolt less because it uses one rotor, and one static port, instead of the two of each used by the Hurricane. But yes, the Hurricane had a much more powerful blower than the Thunderbolt.

[QuantumCurse]

Yes, because it receives more air coming into the rotor since the four port side faces the siren's intake. Same with naturally aspirated sirens too, for example you will hear the 12 port side of a 9/12 ACA siren slightly louder than the 9 port side, since these have the 12 port side on the same side as the siren's intake, and that side therefore receives the most air. This is reversed on Federal 9/12 sirens, where the 9 port side is dominant, because it's on the same side as the intake. If you listen to a Model 2T, it's the same 4/5 rotor, but both sides are open and take in roughly the same amount of air, so neither note is really as dominant as it would be if the intake was restricted to one side.

IIRC the reason the ACA Hurricane has the dominate undertone is because more air comes from the blower. Is this the same on the Thunderbolt?

Same reason i described. Hurricane's had the 8 port rotor on the bottom side of the motor, which is the side air comes in from the blower. Most of the air left the siren through the bottom rotor and significantly less left through the top, which was the 10 port rotor(there were different ratios made, but all the ones known to exist were 8/10) due to the distance between the two, making it much quieter than the 8 port rotor. This affects the Thunderbolt less because it uses one rotor, and one static port, instead of the two of each used by the Hurricane. But yes, the Hurricane had a much more powerful blower than the Thunderbolt.

Thanks for the info!

[QuantumCurse]

I got the flange and pipe back from the machinist today! Here are the pictures.