Antigravity

I'd appreciate some feedback on how antigravity works. Not the handwavium Honorverse physics behind it, but how it is applied?

As an example, for aerial transport (air cars or aeroplanes) is the antigravity unit a discrete piece of kit bolted to the frame that lifts the aircraft by dragging it up (like Stephanie's antigravity harness), or does it project a field making the whole craft unaffected by gravity?

Another aspect is the power usage. If the power required is the same as would be produced by the weight of the craft then it makes sense to just use the antigravity for VTOL, leaving support during the flight to airfoil wings.
However if it is less, due to just producing a field rather than dragging up the craft against gravity using brute force; then we have a perpetual motion machine. Large engine with heavy pistons dragged up by antigravity then switched off to drop producing more energy than goes in.

Bu9 people reacted in horror when I suggested an up and down profile for an aircraft with just anti-grav (no other engine, just a glider). So I don't think they do that.

Personally I don't have a problem with the main handwavium predicates of all faster moving "space fiction", that being the existence of hyperspace, warp, etc., (FTL movement and comms), medical nanotech/quicker healing methods, and usually anti- or countergravity, non-chem burning weapons, etc.

At least RFC/MWW keeps the handwavium to a minimum. Other than the unreasonable power densities sometimes (and virtually all gravity related so far as I can tell) he does a pretty good job sticking to his base rules.

Fully agree with every word you've written.
I just want to know how in this instance it is applied.

SharkHunter wrote:Personally I don't have a problem with the main handwavium predicates of all faster moving "space fiction", that being the existence of hyperspace, warp, etc., (FTL movement and comms), medical nanotech/quicker healing methods, and usually anti- or countergravity, non-chem burning weapons, etc.

At least RFC/MWW keeps the handwavium to a minimum. Other than the unreasonable power densities sometimes (and virtually all gravity related so far as I can tell) he does a pretty good job sticking to his base rules.

kzt wrote:Bu9 people reacted in horror when I suggested an up and down profile for an aircraft with just anti-grav (no other engine, just a glider). So I don't think they do that.

Hyperbole much? Hardly "horror".

There's a difference between "countergrav" and "anti-gravity". Countergrav only negates the effects of gravity - it provides no lift against gravity as a true anti-gravity effect would, despite what any of the books say about CG belts. That's always been my impression, and until I'm told otherwise by those who *know* (either David or someone else in BuNine), it always will be.

For flight, CG takes the weight off the craft, and the RCS, engines, or some other propulsive method is used for movement, and wings or whatever provide lift and/or control.

If it negates gravitational mass, does it also negate inertial mass? If it does, the lightest breeze would blow people using AG belts around like thistledown. If it doesn't, it's just driven a super-dreadnaught sized hole through General Relativity.

JohnRoth wrote:If it negates gravitational mass, does it also negate inertial mass? If it does, the lightest breeze would blow people using AG belts around like thistledown. If it doesn't, it's just driven a super-dreadnaught sized hole through General Relativity.

I would think that 'countergrav' implies that it counteracts gravity and not mass. So no real problem with relativity.

JohnRoth wrote:If it negates gravitational mass, does it also negate inertial mass? If it does, the lightest breeze would blow people using AG belts around like thistledown. If it doesn't, it's just driven a super-dreadnaught sized hole through General Relativity.

Countergrav does not negate inertial mass. And yes, of course it throws a hole through General Relativity. But so would any form of antigravity, or anything which cancels inertial mass. None of that works in General Relativity.

MaxxQ wrote:There's a difference between "countergrav" and "anti-gravity". Countergrav only negates the effects of gravity - it provides no lift against gravity as a true anti-gravity effect would, despite what any of the books say about CG belts.

You mean like:

More Than Honor
A Beautiful Friendship
Part VII wrote:Stephanie whooped in sheer exuberance as she rode the powerful updraft. Wind whipped her short, curly hair, and she leaned to one side, banking the glider as she sliced still higher. The countergrav unit on her back could have taken her higher yet—and done it more quickly—but it wouldn't have been anywhere near as much fun as this was!

Perhaps the countergrav units hang-glider pilots use are mis-named, but there is ample textev that personal countergrav units can provide at least limited amounts of lift -- negative weight, so to speak.

Daryl wrote:Another aspect is the power usage. If the power required is the same as would be produced by the weight of the craft then it makes sense to just use the antigravity for VTOL, leaving support during the flight to airfoil wings.
However if it is less, due to just producing a field rather than dragging up the craft against gravity using brute force; then we have a perpetual motion machine. Large engine with heavy pistons dragged up by antigravity then switched off to drop producing more energy than goes in.

Oh, well they've already got that. Any ship with a wedge can generate far more kinetic energy than its fusion reactors produce.