The Emthruster: Thrust without reaction?

[Drashner1]

I looked up the beam-core concept on Atomic Rockets and its actually a different design from Forward's (at least I've never heard of him doing work on that design). Beam-core drives use an equal mix of matter and amat and would probably be significantly harder to build and certainly have much higher amat requirements. For this reason, they might have been more expensive to build and therefore less common or taken more time to be built in quantity.

Another factor could be the use of boostbeams and mag-brakes. These might both accelerate and impede the development of beam-core ships. Accelerate in that their use would reduce the amount of amat fuel needed. Impede because they would amplify the performance of existing ships and so raise the bar that a beam-core ship would need to get over to demonstrate a return on investment sufficient to build them in quantity.

Todd