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Hydrofoils are whack

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Redmercury

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« on: <09-11-12/2247:24> »
I was just skimming through the arsenal vehicle mods to put together a drone with a rigger cocoon and gecko tips, (along with some other goodies) when I glanced over hydrofoil capability I had to read it, as hydrofoils are pretty sweet. I don't know about the amount of acceleration boost,  but it absolutely doesn't damage fuel efficiency. In fact it should boost it by reducing drag, that's why it can go faster than a boat planing on its hull. As far as I can tell the only downsides to having hydrofoils would be increased maintenance and draft.  If this makes hydrofoils too unbalanced then take away the acceleration boost, as the hydroplane would hurt acceleration before it lifted the hull out of the water.

beowulf_of_wa

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« Reply #1 on: <09-11-12/2312:33> »
maybe they wrote it that way so Johnny Rigger won't make a Formula 1 racer into a hydroplane Amphibian, which might unbalance the game for some GMs.

GM: they're still chasing you. you're running out of road, what do you do?

JR: i head for the waterfront and aim for the dock.

GM: ??? ok, you're now flying down the dock at 75mph, the end is rapidly approaching, can your car swim?

JR: when i hit the end of the dock, i deploy my hydroplane foils,,

GM: Fraggin REALLY!!!!?!?!?!?!
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Redmercury

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« Reply #2 on: <09-11-12/2316:43> »
As always GM rules. I would never allow runners to do something like that, not without sacrifices. There are mechanic hurdles, a lot of them to something like that. I won't even get into it. That does sound sweet though. That's one classy way to ditch the rentacops.

CanRay

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« Reply #3 on: <09-11-12/2319:28> »
maybe they wrote it that way so Johnny Rigger won't make a Formula 1 racer into a hydroplane Amphibian, which might unbalance the game for some GMs.

GM: Fraggin REALLY!!!!?!?!?!?!
Or unbalance some GMs.  :P
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beowulf_of_wa

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« Reply #4 on: <09-11-12/2321:38> »
it is a quick way into and out of chicago,,, or canadia,,
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CanRay

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« Reply #5 on: <09-11-12/2325:15> »
it is a quick way into and out of chicago,,, or canadia,,
Depends on the part of Canada.  Some parts of Canada are landlocked.
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beowulf_of_wa

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« Reply #6 on: <09-11-12/2326:16> »
it's a formula 1 car, ray,,, it's quick on land too,  :P
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The Wyrm Ouroboros

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« Reply #7 on: <09-11-12/2329:55> »
Even boats that have convertable hydrofoils have to be at a dead stop for that.  And the suckers are big and obvious.

So yeah, sure, I'd allow the rigger to build it.  But I'd laugh my ass off as I described how horribly he's killed, scattering himself across half a mile worth of water after tearing his vehicle apart when he deployed his hydrofoils ...
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Redmercury

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« Reply #8 on: <09-11-12/2330:45> »
The problem is when you run out of fuel. I'm pretty sure those things wouldn't have multi-fuel engines, and the local refill probably wouldn't have race formula fuel. But hey, as long as the engine lasts as far as where you're going.

beowulf_of_wa

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« Reply #9 on: <09-11-12/2345:06> »
hate to disagree with ya on this, wyrm, but all the video i've seen shows the boats in motion long before they pop up and fly on the foils. boeing made one that flew over the water at over 90mph, powered by a big jet engine.

considering that a formula 1 car's undercarriage is as smooth as they could make it to ease airflow, and it has all them spoilers and wings to help hold it to the road, i'd say that hitting a switch to pop out some hydrofoils and adjust the wings for level flight is perfectly acceptable.

the biggest problem would actually be the fuel, those cars don't go far on a tank, and boats go even less for a gallon.
Carpe Noctem (seize the night)
Carpe per Diem (seize the pay), Carpe Dentum (seize the teeth), Carpe Denim (seize the pants)
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no, i won't "just get over it."

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Thrass

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« Reply #10 on: <09-12-12/0811:06> »
actually if f1 cars are that sophisticated that I think they are, they are not completely smooth
the "sharkskin effect" makes you have less friction if you google it you find links like:
http://news.softpedia.com/news/The-Shark-Coating-42520.shtml
(which is 2006 where they already had that technology in aircrafts and just wanted to apply it to the lacquer)
, that explain it...

other then that... we are talking about 60 years into the future,
you can easily get a hovercraft that ca do the land/water switch without stopping, while being at full speed
so I think it'ld be okay for a water ready car to hit the water and then convert without dronwing at a reasonable speed
because it imho dosn't impact on the game balance at all
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PeterSmith

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« Reply #11 on: <09-12-12/1006:20> »
hate to disagree with ya on this, wyrm, but all the video i've seen shows the boats in motion long before they pop up and fly on the foils. boeing made one that flew over the water at over 90mph, powered by a big jet engine.

Yes, but they were in the water at the start of their acceleration. A vehicle jumping off a ramp/pier and into the water at high speed will want to slow down considerably (near stop) before extending retractable hydrofoils, otherwise the foils will experience severe pressure on their leading edges. Probably enough to rip them off completely as the formula for determining the pressure (P=Surface Coefficient*fluid density*velocity^2) will ramp up considerably as velocity increases.

considering that a formula 1 car's undercarriage is as smooth as they could make it to ease airflow, and it has all them spoilers and wings to help hold it to the road, i'd say that hitting a switch to pop out some hydrofoils and adjust the wings for level flight is perfectly acceptable.

Given that the density of water is about eight hundred times greater than the density of air, I don't. You're still dealing with fluid flow, all of the sudden the forces exerted on the vehicle are going to skyrocket once you go from air to water.

the biggest problem would actually be the fuel, those cars don't go far on a tank, and boats go even less for a gallon.

Fuel consumption is secondary, although it is true that boats get horrible fuel efficiency when compared to ground vehicles. When boating, fuel consumption is not measured in miles per gallons, it's measured in gallons per hour. If you take the time to translate that into MPG you end up looking at gallons per mile.

No, the primary problem will be transferring power from the engine to the drive system. For cars, it's done through a transmission, a differential, and then the wheels. For boats, it's done through a much simpler version of a transmission called a reduction set, then to the propellers/impellers (depending on the final drive). The reduction set does not have a series of gearings, there is simply a set of gears that reduce the RPMs from the engine's thousands down to tens. Depending on the design of the final drive (azipod versus traditional shaft) there may also be a reverse setting. So you have two drive systems that have to split just after the engine.

Now you need to get the power down to the water, which requires you to put something *in* the water. You could have a partial hydrofoil system, where a hull is partially removed from the water. This leaves the backend of your car submerged, you're not going to go too much faster than a traditional auto/boat combo (think a DUKW). Keep in mind there is a severe reduction in efficiency when you make the transition. The DUKW went from a 400 mile range to a 60 mile range just by crossing from land to water. A partial hydrofoil will have less of a reduction, as less of the vehicle is submerged and fighting that drag. Or you could have a full hydrofoil system, in which the drive system is part of the foils. However that will increase the surface area of the foils, increasing the drag when they slam into the water at speed, which will increase the chances of having the foils ripped away. Or you could stick a turbine on your car to drive the vehicle when it's hydrofoiling, but now you're looking at a second powerplant and all of the associated problems (space, fuel, weight) that go with that.

In the end, if a player came to me and said: "Hey, I want a car that turns into a hydrofoil." I'd tell them no.
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beowulf_of_wa

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« Reply #12 on: <09-12-12/2015:08> »
fair enough, all valid points for current tech.

though i imagine that 60+ years in the future, someone will have an electric formula 1 style amphibian car/hydroplane. think of it as M.A.S.K. in Shadowrun and on the water.
Carpe Noctem (seize the night)
Carpe per Diem (seize the pay), Carpe Dentum (seize the teeth), Carpe Denim (seize the pants)
Carpe Panem (seize the bread/capital)

no, i won't "just get over it."

NERPS!! for idiocy! NERPS!! for the minty fresh feeling! NERPS!! for gods! NERPS!! for guard duty!

The Wyrm Ouroboros

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« Reply #13 on: <09-12-12/2016:00> »
Thrass, Beowulf, there's already been a vehicle in the game that has had retractible hydrofoils, the Colorado Craft Cigarette-Hydrofoil.  And in order to switch from the cigarette to the hydrofoil, you had to be still - because the mechanism would tear off mid-conversion if you weren't.  If you've a purpose-designed hydrofoil, sure it stays in the water before it has enough speed and flow over the 'foil to lift the vehicle into full-speed hydrofoil mode.  What you aren't doing is going 80kph, then shoving the blades into the water.

Look, you've driven down the road, rolled down the window, and put your hand outside the window, right?  Unless you're flat on, your arm's going to zip up and down.  if it's flat to the wind, god help you, your arm goes straight back and ouch.  Imagine this with a fluid which, as PeterSmith said, is like 800 times the air density, then instead of your arm (being a relatively flexible, resilient limb) make it a metal strut - relatively inflexible.  And when it hits ... snap.

And seriously?  This isn't game balance.  This is just relative realism.  Sure, we got magic, matrix, and cyberware, we have riggers and elves and dragons and all that, but when you get down to it, the laws of physics are still generally applicable.  You hit the wall at high speed, you go splat ...
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All4BigGuns

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« Reply #14 on: <09-12-12/2032:22> »
Thrass, Beowulf, there's already been a vehicle in the game that has had retractible hydrofoils, the Colorado Craft Cigarette-Hydrofoil.  And in order to switch from the cigarette to the hydrofoil, you had to be still - because the mechanism would tear off mid-conversion if you weren't.  If you've a purpose-designed hydrofoil, sure it stays in the water before it has enough speed and flow over the 'foil to lift the vehicle into full-speed hydrofoil mode.  What you aren't doing is going 80kph, then shoving the blades into the water.

Look, you've driven down the road, rolled down the window, and put your hand outside the window, right?  Unless you're flat on, your arm's going to zip up and down.  if it's flat to the wind, god help you, your arm goes straight back and ouch.  Imagine this with a fluid which, as PeterSmith said, is like 800 times the air density, then instead of your arm (being a relatively flexible, resilient limb) make it a metal strut - relatively inflexible.  And when it hits ... snap.

And seriously?  This isn't game balance.  This is just relative realism.  Sure, we got magic, matrix, and cyberware, we have riggers and elves and dragons and all that, but when you get down to it, the laws of physics are still generally applicable.  You hit the wall at high speed, you go splat ...

It's realism, sure, but it's going too far with the realism at the expense of story, awesome cinematic action scenes and fun. Taking those into account, dump the "realistic" approach in the nearest toxic-waste dump, IMO.
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