[inexcf]

I remember this being a horrible idea for many reasons.

One reason being the speed needed at the start which probably meant most loads burning up in the thick atmosphere immediately.

Another reason being that if you would use it to start a rocket which will only use the spin launch as a booster replacement, you would run into the problem of the fuel being pressed towards the front of the rocket as it is constantly decelerating after the launch. So you would probably need a system to actively move the fuel down to the nozzle.

[Manuel_D]

The Excalibur 155mm artillery shell is supposedly subject to twice as much acceleration as the spin launcher, and it has a solid rocket motor. So it's probably possible. But solid rocket motors are less efficient than liquid fuel.

[dudinax]

Maybe a small solid booster to keep it accelerating immediately after launch before the liquid fuel kicks in.