We derive the Woodward transient mass effect from Carver Mead’s G4v Machian gravitation through two distinct channels: scalar (mass fluctuation) and vector (thrust mechanism). We identify the London Moment in rotating superconductors as the physical precedent for non-suppressed Machian effects in coherent media. In the London Moment, the superconducting electrons exhibit order-unity coupling (λ≈0.72) to the cosmic inertial frame despite the Planck-scale coupling constant χ= ℓ2 P. We argue that the PZT stack in a MEGA device operates in a similar regime of “Collective Electrodynamics”: because the piezoelectric domains respond coherently, the coupling is to the cosmic potential (ϕ0 ≈c2) rather than a suppressed local Newtonian potential. The scalar channel produces mass fluctuations δm∝¨ρE via the Abraham equation under the Mach ansatz ρE = ρ0ϕ. The time-symmetric (retarded + advanced)/2 structure forces even time derivatives; the Mach normalization λ= ϕ0/c0^2 ≈0.72 ensures order-unity coupling. The vector channel provides thrust via Mead’s momentum coupling ⃗p= m⃗v(1 + λ). The ℏin the wave vector cancels with χ= ℏG/c3, leaving G/c2—the same ℏ-cancellation mechanism demonstrated by the London Moment. Net thrust arises through mechanical rectification in MEGA devices or electromagnetic rectification in MLT devices.

This is an early fourth draft and not yet at preprint status.