I may have missed it somewhere, but how does the impeller wedge in the Honor Harrington series work. I am only a couple of books in, but I don't quite understand how the impeller wedge works to offer both propulsion and an invincible shield for part of the ship.

Can someone explain it in stupid person terms? The explanations might be a bit over my head in the books for me to actually understand it. I do understand the warshawski sails, but its the wedge that gets me.


4 Answers 4


You can find everything on the Honorverse wikia.

The wedge was a pair of extremely > powerful gravity bands located above and below the generating ship. Both bands were inclined such that the forward end, or "throat", was far deeper than the aft end, the "kilt". The wedge was capable of accelerating a vessel to near-light speed.

The wikia page has further details.

  • Thanks, I didn't realize there was a wiki. I guess i'll start browsing that. Commented Jan 18, 2011 at 22:26

The Honorverse wiki says of the Impeller drive: The impeller drive created a pair of stressed gravity bands above and below a ship, known as the impeller wedge.

The gravity bands allows a ship to effectively 'surf' on a space-time wave of it's own making. Related technologies allow the mechanism to convert to a 'Warshawski sail', for use within hyperspace waves.

For even more comments about the technology, Pearls of Weber: Honor Harrington is a collection of posts by David Weber containing background information for his stories.

  • Even in N-space, a lot of the energy to accelerate the ship and maintain the gravity stress bands comes from interaction with the alpha-band of hyperspace. (This may have been a retcon after realizing that even fusion power with perfect efficiency wouldn't be enough to generate the amount kinetic energy big ships get up to.) Commented Nov 29, 2015 at 4:08

You could think about it as the impellers creating a gravity well which the ship falls down. The steeper the well the faster the acceleration. The only thing which doesn't fit this model is the compensators. Since gravity works on all elements equally you wouldn't need an inertial compensator since you were effectively free falling down the well


I always pictured it as analogous to the way a watermelon seed will shoot from your fingers if you squeeze it. The upper and lower stress bands "squeeze" the ship, (which is why the throat is wider than the kilt) and because the engines generating the bands are in the ship, it shoots forward and can't escape the "squeeze" so it keeps going. Not very scientific, but a useful picture.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.