kilemall
SOC-14 5K
Probably required robot brains for emergency safety and/or external control mechanisms like railroad Positive Train Control.
New VTOL Aviation Propulsion Systems
- Thread starter Spinward Flow
- Start date
kilemall
SOC-14 5K
Umm no the correction was one digit down for the 1977 version- so from 6 MCr to 600000 Cr. The 1981/TTB version you seem to be working off of was the already corrected price point, so understandable how you got there but definitely not logical to apply- try out those ATV/AFV prices for example.Airraft, CT (with Book 4 errata) CR 60,000. If you use this grav vehicles get used much more. I know most people don'tbut I do.
The follow-on paragraph is relevant, prices fall 5-15% per TL. So let's call it 10% per TL and exact same specs- by TL12, interstellar norm tech the air/raft is 360000 Cr. Still not a mainstream civilian asset but certainly a more affordable professional tool.
The personal norm is probably either 'gravtaxi' or rental.
I'm good with the pricing there considering the darn things are suborbital, IMO it SHOULD be like a private plane or helicopter in our currrent RL.
MgT drops the pricing considerably, so one of those your universe your desired effect.
kilemall
SOC-14 5K
BIG deal for militaries and scouts. No accident each one of those Type S comes with an air/raft.
The roads remain in cities, for pedestrians and very light personal vehicles (bicycles, personal scooters. There were also be "streets" acting as corridors for the grav vehicles so that they don't have always fly over the city. But these space don't have to be necessarily efficiently contiguous. You'll major arteries to handles more traffic (since it won't just stack, you'll still need some kind of "lanes"), but, also, you can have more ad hoc hi rise landing platforms. Not necessarily getting your noodles from the food blimp outside your window, but roofs, and small platforms jutting out the sides of larger buildings.
What you won't have is inter-city roads. There's just no reason to build, much less maintain, those things. Inter-city grav traffic will consume that. All the money saved on not building highways can be put in to making such transportation available to everyone.
It's worth noting that the Striker costs for grav vehicles:
Page 8:
a 1×1×20 cm (or 1×2×10, or 2×2×5 cm), massing generates 1 TT at 0.1 MW.
THe cost per m³ of grav modules is KCr100 and 2 tonnes.
So 1 TT is 0.1 MW, KCr2000, and 20kg.
1 m³ of grav generators are MCr10, 50 TT, 2 tonnes, and 10 MW...
The minimum PP volume means we can't use a fusion PP effectively at TL 9.
Let's throw together a budget TL8 grav sedan...
hull: 1.5×2.5×6m hull, 22.5m³.
front radical slope (20%) and rear moderatre slope (10%), for 15.75 m³ internal. F/R 3.75m² P/S 9m², D/V 15m². SA 55.5m²
Using Ø for negligible.
using current Cr1=US$5 $167,075. usin Mongoose's Cr1=3£, 100,245.
1.138 G's loaded, about 156 kmh
Dry with a 90kg driver, 1.376G, or about 165kmh
So about 600 km range... About a luxury sedan price these days, and with similar performance, but flying.
Page 8:
a 1×1×20 cm (or 1×2×10, or 2×2×5 cm), massing generates 1 TT at 0.1 MW.
THe cost per m³ of grav modules is KCr100 and 2 tonnes.
So 1 TT is 0.1 MW, KCr2000, and 20kg.
1 m³ of grav generators are MCr10, 50 TT, 2 tonnes, and 10 MW...
The minimum PP volume means we can't use a fusion PP effectively at TL 9.
Let's throw together a budget TL8 grav sedan...
hull: 1.5×2.5×6m hull, 22.5m³.
front radical slope (20%) and rear moderatre slope (10%), for 15.75 m³ internal. F/R 3.75m² P/S 9m², D/V 15m². SA 55.5m²
Using Ø for negligible.
| Vol m³ | Tonnes Mass | Price KCr | Power MW | Item | Notes |
| [22.5] | -- | -- | -- | Hull | 22.5 m³, 55.5m² |
| 6.75 | -- | -- | -- | SLoping | Front radical, rear moderate |
| [15.75] | Internal volume | ||||
| 0.13875 | 1.11 | 0.2775 | 0 | Armor | hard steel, 0.25 cm |
| 1 | 1 | 10 | [0.6] | MHD Turbine | 180 l/hr |
| 0.72 | 0.72 | 0 | 0 | Fuel | four hours max output |
| 0.12 | 0.24 | 12 | 0.6 | ||
| 0.4 | 0.2 | 11 | Ø | Avionics | TL9, 130 kmh |
| Ø | 0.0002 | 0.15 | Ø | Radio, 20 km | for ATC |
| 2 | 0.2 | 0.1 | Ø | driver, comfy | |
| 8 | 0.8 | 0.2 | Ø | Pass ×4, comfy | no ls |
| ======== | ======== | ======== | ======== | ======== | ======== |
| [3.37125] | 4.2702 | 33.415 | 0 | totals | figure a rated 1 Td capacity in cargo |
1.138 G's loaded, about 156 kmh
Dry with a 90kg driver, 1.376G, or about 165kmh
So about 600 km range... About a luxury sedan price these days, and with similar performance, but flying.
I'm thinking more in terms of emergency evasion (collision avoidance) rather than routine maneuvering. 0.1G lateral should be enough for routine maneuvers and parking.
Condottiere
SOC-14 5K
Since it's a field effect, and air/rafts don't have wings, it would be a catastrophic failure if you don't have separate modules, and parabolic descent due to forward momentum?
Yeah. I'd assume some redundant capacity and a graceful degradation of capabilities. In reasonable atmospheres, they could have ballistically-deployed safety parachutes, but they're also designed for operation down to vacuum conditions so...
Condottiere
SOC-14 5K
Air bags?
But they engulf the entire person and float out?
But they engulf the entire person and float out?
Hmmn.
The problem is what happens when your air/raft stops air/rafting, and where it is when this happens.
For at least the versions carried on starships, the fallback has to work in any atmosphere, or none. It also has to be capable of zero-zero operation (no airspeed minimum, no altitude minimum) and to the maximum extent possible, prevent damage to whatever it lands on (so ejection seats or one-shot grav chutes are marginal in this case).
My initial guess is retro/lateral rockets for collision avoidance, and the ability to overdrive remaining grav modules if one or more of them fail (they'll burn out, but with luck will last long enough for a safe landing).
I still don't think those are practical.
First, the power they'd need to actually instill enough change would be very high. A car can swerve very quickly, for example, thanks to the traction of the wheels. We've seen in air shows how fast aircraft can respond. Using rockets for something like that, I mean, that's just a lot of rocket. I look at things like JATO assistance. I'm sure it's a kick in the pants, but it takes a lot of time to ramp up and do anything. Small model rockets just fly off the pad, but even not much larger rockets are noticeably slower.
What happens if someone "jerks the wheel" in that hotel reception area?
It's just... a lot of rocket, a lot of power.
I think that the grav vehicles just have to have very powerful acceleration, in any dimension, to be safe enough to handle avoidance.
I think that the systems can be made safe and redundant enough to work in a metropolitan area. As long as they're not physically damaged (hit by something), I think they can side on caution to abort and land safely. In a metro area, automated traffic control can help dramatically mitigate mid-air collisions. They can have redundant grav modules, battery/capacitor backup to handle enough power for emergency descent. You just better hope the thing floats if it fails over water. (Perhaps the optional emergency water landing inflatable ring feature would be of interest to you?)
The "someone jerks the wheel" problem isn't one. The JATO system isn't for normal maneuvers, and can't be triggered manually (unless it gets hotwired but that's a separate issue). It's for "whoops, there's a building in the way!" The canon air/raft has about 0.1g of acceleration left after hover, and simply doesn't turn very quickly. The only direction it can move quickly is down (with a quick off-on blip of the antigrav), which is fine for avoiding other flying vehicles, but kind of impractical for terrain avoidance...
Fast turns in atmosphere can be accomplished with a combined roll/pitch maneuver, but this is very inefficient and high-drag. Likewise, rapid braking to about 40kph airspeed (yeilding a survivable impact) can be accomplished by pointing the craft nose-up to present the flat bottom surface to the airstream. In thin/trace/vacuum atmosphere, of course, it won't help at all.
Says who?
Who designed that thing? .1g? I bet that looked great on the brochure. "0-60mph in FOUR MINUTES"
At 0.1g, an Air/Raft would go from 0-120 kph in about 33 seconds.
Remember that it is an Air/Raft, not a Grav Car. (Air/Raft is also variously called a Floater or Flyer in CT).
I think the concept of the Air/Raft is that it is a slow and (reasonably) stable transport platform for cargo or personnel; it is not necessarily built for speed. There have been higher speed civilian grav vehicles in Traveller that I think would typically be classified as Flyers (or "Grav Car" in T4) that are a better fit for what I believe you are discussing. There might be a wide range of performance specs for particular Air/Raft models, but speed and acceleration are not necessarily the primary concerns, depending upon intended use.
Spinward Flow
SOC-14 5K
I avoided discussing the Speeder because it is explicitly distinct from an Air/Raft in CT and other rulesets (though it is a very high speed grav-transport). There is a velocity regime that seems to fall between the "standard" operational range of the air/raft and the speeder.
Spinward Flow
SOC-14 5K
The Air/Raft is the grav vehicle equivalent of a forklift.
The Speeder is the grav vehicle equivalent of a roadster.
Both are featured in LBB3.81 in the vehicles section.
The Speeder is the grav vehicle equivalent of a roadster.
Both are featured in LBB3.81 in the vehicles section.
Under Striker's speed charts, 120kph is what you get with 1.1g acceleration capability.
Keep in mind that in 1977, 120kph was fast for an automobile in the US! Not in actual capability -- most cars could exceed that quite handily. But the national speed limit was 55mph (90kph) at the time as a fuel-conservation measure.
