Composite motor production

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Well-Known Member
Sep 11, 2002
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I have a question that may sound strange....

1) I think that I remember reading somewhwere that composite motors cannot be machine made, but must be 'built' by hand.

2) This is what lead to the 'reload' type motor as this cuts down production costs.

Does anyone know if this is true? I just cannot believe that a machine cannot build these motors.

Weren't Canaroc's motors composites? They were machine made...

Just curious...
Composite motors can be machine made. However, the cost for the machines would be very expensive and there would need to be a large enough market to justify the expense.

As I understand it, for efficiencies of production, a company would need a continuous propellant mixer. This is a machine that is running 24 hours a day, 7 days a week. The makers of solid rocket motors for the military and civilian space market use these machines. If these machines should ever stop, they require a total tear down and cleaning before they can mix propellant once more. These machines are designed for mixing HUGE amounts of propellant.

Molded casing will save several steps as will some way to seal the other end of the casing quickly. The AeroTech F20 Econojets and the NCR Dark Star motors had these features.

Yes, reload motors are much more efficent to sell in terms of production time and resources.

Canaroc motors used a much more fluid composite propellant (I understand boat resin was one of it's components) which could be poured into the casing. However, this propellant had a low ISP which is why the performance was no improvement over BP motors in the same size casing.
AMW, and I believe Aerotech motors, are also poured. They don't have someone in thier beating propellant in a tube with a stick (See Rocket Challenge). It has to do with the binders, and other chemicals they put in there...

That is a big reason why you don't see any mass produced AMW motors smaller than 54mm.... any smaller than that, you can not pour it (the bead clings to the side of the tube and folds in on itself, causing air bubbles.)
I don't know about AMW but AeroTech pours/casts propellant into paper tubing. This propellant is then cut and cored. These propellant slugs are then installed into casings for single use motors.

Canaroc poured their propellant directly into the motor casing.