J135W Nozzle Question

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eastvolt

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Just inspecting my AT J135W reload, and although the nozzle has (6) small orifices and (1) large orifice in it, only (2) small orifices and the (1) large orifice are "open."

Is this correct for this reload. I know some reloads, the nozzles don't get completely milled out and you need to use a knife to clear them out. But i'm not so sure with this, since it does say so in the instructions.

THanks
Dan
 
That is one of AT's medusa nozzles. They open some but leave some closed to control the burn rate and pressure. Don't open them of any are closed. This is normal. (The J415 is the same way, but has more nozzles opened)

-Aaron
 
Just inspecting my AT J135W reload, and although the nozzle has (6) small orifices and (1) large orifice in it, only (2) small orifices and the (1) large orifice are "open."

Is this correct for this reload. I know some reloads, the nozzles don't get completely milled out and you need to use a knife to clear them out. But i'm not so sure with this, since it does say so in the instructions.

THanks
Dan

The longer-burn motors use a smaller total nozzle throat area. The AT medusa nozzle is multi-purpose for several reloads, depending on how many are drilled out and what diameters they are. It also uses much less resin in molding the nozzle and leaves more room for propellant inside the casing.

It appears that the core and two orifices are drilled out for the 54/1280 longburn (0.228 and two 0.161):
See: https://www.aerotech-rocketry.com/c.../54mm_hp_rms/54-1280/54-1280_j135w-m_assy.pdf
 
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