Chief: Awright, I dunno what you jokers done to the Doc; but you’re not doing anything to me. You read me on this?
Mukh: I liked the Doctor. What happened to him?
Chief: You’d know that better than me. The Captain had to give him a week of shore leave on the Cat Girl Planet to withdraw his transfer request. ... He said something about seeing you eat a box of towelettes being the last straw.
Mukh: It isn’t my fault. They’re good on you or in you, either way they’re lemony fresh!
Tivk: Perhaps we should send the Doctor a card?
Chief: Never mind that now! I’m here to familiarize you with the D20 Omnidirectional General Lifter, also known as a hopper. This is the current model and a great improvement over the earlier versions used by the Fleet.
Nok: Yes, it has cup holders.
Chief: What the hell are you doing in there?
Nok: I needed something to put my mug in. Also it’s too bright out there.
Chief: Get ... no never mind. The rest of you pile in. I will review the design features.
Tivk: Should we acquire beverages first?
Chief: Get.In. Nok, you have basic lifter certification, right?
Nok: Yes Chief. Human control layout takes a little getting used to.
Chief: Anything in particular giving you a problem?
Nok: I’m having trouble reaching the nob that adjusts my seat.
Chief: Right. Now this model is an improvement over previous models in that the lifter alternates between downward thrust and motive force at 300 cycles per second. Earlier models used air jets or peroxide rockets to provide motion.
Tivk: The cycling feature saves mass at the expense of energy but there are many batteries, radio thermal generators and MHD designs that are more compact than rockets and propellant.
Chief: Yes Mr. Tivk. Anything else to add?
Tivk: Terrans stole the idea from my people?
Chief: The Open Gravitics License you signed says different. Take it up with the patent office. Now as in all things the square-cube law is your enemy.
Mukh: I think the real enemy is the inverse square law. The further you get from the body you lift from the more power you have to use as the lift field spreads out beyond the hopper.
Nok: It does give birds a rest. Also if you convoy lifters you get more altitude and speed from them. The beam spill hits other lifters lightening their load a bit.
Chief: ... It is your enemy on the sense that a craft’s mass will increase by the cube of its length. Build your hopper twice and big and it weighs eight times as much ...
Tivk: Maybe you Terrans should steal carbon nanotubing technology from us next.
Chief: ... but the area for thrusters is only four times as much. This is compounded by thick armor. Earlier attempts to build lifter powered AFVs had ludicrously large lifters on outriggers. Armoring those proved impractical.
Nok: I don’t see why armor is a problem. No one can build effective armor that will stop a beam cannon. The only armor is speed.
Chief: Either way you want as big a set of thrusters as you can mount. Now this being a human design the captain wanted to make sure you fellas will be all right when we fire it up. Some people react worse than others to lifter tech.
Mukh: Oh! I know, the gravity tremors mess with your inner ears right? Poor land dwellers.
Chief: Fortunately there are a variety of medications that will prevent illness with little or no side effects. Please fire it up Mr. Nok.
Nok: Aye Chief. Once around the hangar?
Chief: Keep her stationary we’re just seeing if you guys can take the lifter effects. Don’t forget the lift field has to thrust against something, like the deck. If a crewman gets between the deck and the lifter ... speed bump.
Tivk: Isn’t there some oscillation associated with Terran lifter units?
Chief: You got me there, Mr. Tivk. We called the earlier models ‘rattlers’. Riding in them was not fun. Everyone okay?
Mukh: .F' taugn! Uuuuuuurrrrk!
Chief: Land it! Land it! Everybody out. Get to the head Mukh.
Nok: Watch out for my beverage!
Chief: Wow the lad can jump when he has to! That was a close call. Well two out of three isn’t bad.
Tivk: It’s probably the subsonics. I find them disconcerting as well. I will design a countermeasure, Chief.
Nok: What do you get when you regurgitate a meal composed of cleaning materials?
Mukh: Ha. Ha. You’re funny as an empty lifeboat berth in an evac.
Chief: The additional safety features include lifter fields being projected around the hopper as a sort of crumple zone to minimize damage from collision. Your people never thought of that did they, Tivk?
Tivk: ... we have more faith in our pilots. How hard can you hit something before the lifter overloads and you fall out of the sky? It must be hard to shunt power that fast.
Chief: We have a design feature to take care ‘a that ... The hopper can only rise ten meters.