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Old Oct 17 2009, 06:12 PM   #1
Golden Talisath
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Default Flying a dragon: how high can you go?

I was just wondering (I might be wondering about to many things): when a rider flies on a dragon, how high can a dragon take him into the air before the man starts to feel dizziness and such? And are there limits to as how high can a dragon go? I know F’nor couldn’t breathe when Kanth took him to the Red Star, but was it said that Kanth had the same troubles?
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Old Oct 17 2009, 06:36 PM   #2
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Default Re: Flaying a dragon: how high can you go?

I don't think dragons would have any trouble with the oxygen; I seem to remember they can last about 10 minutes without fresh oxygen. I can't find a list for how high a person can go before it gets hard to breathe, but I imaging the dragon would change course to save their rider.

As for how high a dragon can fly, there is a picture/chart given in the DLG, I'll try to reproduce it here.
(Fight & Flight refer to the maximum altitudes attainable by fighting or flying dragons, respectively)

--
=
=
--
=
=
--Maximum Flying Height
=
=
--Tall Mountain Height
=
= Avg Mountain Height
--Maximum Fighting Height
=
=
--Highland
=
=
-- Ground

Hope that helps.
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Old Oct 17 2009, 07:02 PM   #3
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Default Re: Flaying a dragon: how high can you go?

Anne writes about riders looking down from thousands of dragon lengths altitude.

If a dragon was 30 feet long, just 968 dragon lengths would put the rider as high as Everest and in need of oxygen. So, thousands of dragon lengths would put the rider at least 11 miles up.

But some readers read dragon size as 30 metres. So: thousands (plural) of dragon lengths, in this case, would put the rider over 37 miles up!
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Old Oct 17 2009, 11:55 PM   #4
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Default Re: Flying a dragon: how high can you go?

That reminds me of the arguments I've seen about Eomer's Eored being "thousands of leagues" from home. Things like that can really get people stirred up when it's really just a momentary lapse or a slip of the pen (or keyboard). It's easier to answer about the dragons, though. They can fly as high as they think they can.
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Old Oct 18 2009, 12:46 AM   #5
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Default Re: Flying a dragon: how high can you go?

The standard pressure altitude in (pressurized) aircraft is 8,000 feet. Above this, physiological affects attributable to the reduced partial pressure of oxygen will begin in some. By about 12,000 feet, most people will be affected. Above 15,000 feet only rare persons (e.g. Sherpas) will be able to function for more than a few minutes.

Having no means of oxygen support after the First Pass until the late Ninth Pass, Pernese dragons and riders will not be operating (on average) above a Pernese pressure altitude equivalent to 10,000 feet on Earth. This will be lower than 10,000 feet, by some proportional amount, due to Pern's lesser gravity.

If we assume greens are 20-25 feet, blues 25-30, browns 30-35, bronzes 35-38, and golds 38-42 (excepting Ramoth at 45), they will not be operating "thousands" of dragon-lengths in the air. It may seem that way to the riders, but it won't work. I think we can just set aside the DLG error of giving these numbers as meters vice feet.
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Old Oct 18 2009, 03:45 AM   #6
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Default Re: Flying a dragon: how high can you go?

I'll second what ED said. A rapid ascent to above 10-12000 feet is not advised - you want to spend at least a few hours if you want to give your body even a chance to aclimatise slightly and cope for long enough to fight a fall. Ideally, the Weyrs will be situated at an equivalent altitude to 5-10K on earth, so the inhabitants have already become adjusted to some extent to the rigours of the lack of oxygen.

For me, working at 13000 has been a great experience, even limited to shifts of no more than 12 hours at a time. You can really feel the difference in your brain as well as your body - logical thinking becomes very, very much more hard work, and while I found the more lateral and instinctive cognitive processes filling the gap (fastest I've ever done The Times' crossword is up Mauna Kea), you DO NOT TRUST any solo calculations you're forced to make at altitude. [That's what colleagues at sea level are for...]

Physically, whew. Forget about doing anything energetic you don't need to. I'm fairly fit, and used to be in the habit of always taking a flight of stairs at a run. My first observing run there broke me of that habit after I partially blacked out by the top of one flight. Even below 10K, you'll notice the difference, unless you're used to living that high up.

Altitude will inevitably add an extra dimension to Threadfighting. I'd say it's possible above the Pernese equivalent to 10000feet, but only if the Weyrs are already high-altidude - otherwise, even a few hours will be physically too much for the riders. Why risk extra fatal mistakes fighting at 12000ft when you could do the job far more safely at 8000?
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Old Oct 18 2009, 05:24 AM   #7
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Default Re: Flying a dragon: how high can you go?

Hmm, so altitude could be an extra reason for the high fatality rates...
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Old Oct 19 2009, 05:20 PM   #8
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Default Re: Flying a dragon: how high can you go?

If people can get wonky from coming to Colorado, a mere mile above sea level, without proper hydration, I'd sure say altitude could be fatal or at least sickening for dragonriders.
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Old Oct 19 2009, 08:48 PM   #9
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Default Re: Flying a dragon: how high can you go?

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Hmm, so altitude could be an extra reason for the high fatality rates...
In the form of ill-advised jumps between to incautious altitudes and failure to command the dragon back to a safe altitude before losing consciousness? Sure, especially if you're riding a color not known for its independent reasoning ability, and especially if a weyrling. Everyone's physiology is a little different. There is no outward sign of who is going to pass out at 8,000 feet versus who will be fine up to 12,000.
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Old Oct 20 2009, 04:35 AM   #10
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Default Re: Flying a dragon: how high can you go?

Your height, as a dragon rider, is not the governing factor fighting thread. Killing the thread is the major objective. So long as its flamed before it hits ground it doesn't matter if it's caught at 500' or 12000'. Height just gives you longer. A good weyr leader would surely fight from the lowest possible height FOR THAT FALL?
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Old Oct 20 2009, 04:39 AM   #11
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Default Re: Flying a dragon: how high can you go?

Quote:
Originally Posted by ElectricDragon View Post
Everyone's physiology is a little different. There is no outward sign of who is going to pass out at 8,000 feet versus who will be fine up to 12,000.
This.

And to make things worse, there's no predicting when you'll first get altitude sickness.
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Old Oct 20 2009, 10:27 AM   #12
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Default Re: Flying a dragon: how high can you go?

I would imagine that part of weyrling training would involve flying straight, climbing to greater and greater heights, but gradually so as to build acclimatization (sp?)
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Old Oct 20 2009, 10:58 AM   #13
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Default Re: Flying a dragon: how high can you go?

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Your height, as a dragon rider, is not the governing factor fighting thread. Killing the thread is the major objective. So long as its flamed before it hits ground it doesn't matter if it's caught at 500' or 12000'. Height just gives you longer. A good weyr leader would surely fight from the lowest possible height FOR THAT FALL?
They'd probably add 500' - 1000' (as long as the ceiling for that thread fight was proper) just, in case. There are lot's of things that a Weyrleader knows can go wrong. And probably each flight or two, they learn a new thing that can go wrong. Which are the reason for adding a little bit of height for safety.

GH
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Old Oct 20 2009, 12:20 PM   #14
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Default Re: Flying a dragon: how high can you go?

The film in my mind tends to see the Queens' flight at about 500 - 1000' and the fighting wings stacked at about 1000' intervals.
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Old Oct 20 2009, 11:26 PM   #15
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Default Re: Flying a dragon: how high can you go?

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Your height, as a dragon rider, is not the governing factor fighting thread. Killing the thread is the major objective. So long as its flamed before it hits ground it doesn't matter if it's caught at 500' or 12000'. Height just gives you longer. A good weyr leader would surely fight from the lowest possible height FOR THAT FALL?
No, he would fight at the highest altitude possible to give the maximum amount of potential engagement time. Close weather would be a serious problem. Imagine fighting in a minimal VFR environment (3000 feet vertical and 5 miles lateral visibility). You don't have very long to see, move to intercept, flame what Thread you can, and hope that your lower wings are able to intercept what you miss before it hits the ground.

Gravity is a relentless opponent. So is drag. Every maneuver a dragon makes, costs drag. This can be made up two ways: wing-stroke or by trading altitude for airspeed. Now the dragons do have a priceless asset in being able to instantly grab altitude by a hop between to regain potential energy they can trade for kinetic. However, this won't work during an engagement with a particular clump--it's still going downward. Hopping between is a de facto disengagement. Now a lower wing must intercept it. Also, hops between are not without cost. They become fatiguing to both dragon and rider.

It have a disagreement with Thread-fighting tactics as written. I would deploy my large-wing/high-lift dragons at altitude and my small-wing/small-lift dragons lower down. The small-wing dragons would be less prone to exhausting themselves at altitude. Their speed and maneuverability would permit them to chase down what the higher, large-wing, less maneuverable dragons are unable to destroy. Also, each lower wing would have a greater number of dragons to improve the chances of intercept before impact of anything that leaks through.

Unfortunately, the hierarchy of dragon intelligence and social standing, and breeding numbers works against this. There aren't enough large-wing dragons, and unfortunately the small-wing dragons need to be lead.
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Old Oct 20 2009, 11:27 PM   #16
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Default Re: Flying a dragon: how high can you go?

Quote:
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I would imagine that part of weyrling training would involve flying straight, climbing to greater and greater heights, but gradually so as to build acclimatization (sp?)
Correct. In fact, by so determining the limits of each rider, a Weyrleader might determine what wing that rider should be assigned to, and the wings might have fixed altitude assignments. For example, a Weyr with nine fighting wings, divided into three flights, might always fly the first flight, wings A, B, and C, at high altitude, with the second flight, wings D, E, and F at mid-altitude, and the third flight, wings G, H and J at low altitude. Those assigned to A, B, and C wings, might be only those riders who function at higher altitudes (the people who can make it to 12,000 feet on Earth), while those assigned to G, H and J might be those riders who function only to the lower altitudes (the people who can only make it to 8,000 feet on Earth). Wings D, E, and F would be those in the middle.

Although, a more normal distribution would probably have two wings of really high altitude breathers, two of very low and five in the middle band. This would be more of an issue for the first flight than the third.

Last edited by ElectricDragon; Oct 20 2009 at 11:33 PM. Reason: add
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Old Oct 20 2009, 11:35 PM   #17
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Default Re: Flying a dragon: how high can you go?

Quote:
Originally Posted by GHarris View Post
They'd probably add 500' - 1000' (as long as the ceiling for that thread fight was proper) just, in case. There are lot's of things that a Weyrleader knows can go wrong. And probably each flight or two, they learn a new thing that can go wrong. Which are the reason for adding a little bit of height for safety.

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Any aviator will add as much altitude to the situation as he can. You can cure a lot of mistakes with enough altitude.
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Old Oct 20 2009, 11:50 PM   #18
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Default Re: Flying a dragon: how high can you go?

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The film in my mind tends to see the Queens' flight at about 500 - 1000' and the fighting wings stacked at about 1000' intervals.
Let's arbitrarily assume that the difference in planetary gravity correlates directly to pressure altitude. This would make the likely onset of altitude sickness at the low end 7200 feet, and the onset of near-certain altitude sickness at 10,800 feet on Pern.

In Pernese terms, using a green dragon as the yard stick, that would be a roughly 300 dragonlengths (keeping in mind the Pernese don't actually have altimeters) at the low end and 400 dragonlengths at the upper (actual numbers 288 and 432, assuming a 25 foot green dragon).

Assuming things are CAVU (Clear And Visibility Unlimited), I'm going to have my highest flight right up at 400 dragonlengths (10,000'), with the second at 300 (7500') and the third at 200 (5000'). The queens wing would be down at 50 dragonlengths (1250 feet).

Close weather would obviously change matters. Low ceilings would compress the vertical stack if the weather above the ceiling is solid up through the pressure altitude. If not, and there is a layer, or layers, it might be best to deploy a flight above a layer or even between layers. This would be a high-stress scenario for the Weyrleader as there would be little visual contact between the flights and a high probability of Thread "leaking" through. Bad enough to have a low ceiling and solid weather above, but having the Weyr divided up between altitudes between layers would really test its organizational and tactical depth.

Another bad scenario is clear air at pressure altitude, but a cloud deck at some point below which extends all the way to the ground. Again, this compresses the vertical stack, and the queens wing will be right above the cloud deck.

The worst-case scenario is solid weather from the deck to pressure altitude. Under these circumstances, all the Weyr (and Holds) can hope is that there is enough moisture in those clouds to kill the Thread. Because if not, the ground crews are going to have a nightmare battle, and after the weather breaks the dragons and riders will be scorching a lot of burrows and burning fields.
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Old Oct 21 2009, 05:42 PM   #19
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Default Re: Flying a dragon: how high can you go?

We know rainstorms will help drown Thread, but I wonder what effect just falling through a dense cloud would have?
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Old Oct 21 2009, 08:00 PM   #20
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Default Re: Flying a dragon: how high can you go?

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We know rainstorms will help drown Thread, but I wonder what effect just falling through a dense cloud would have?
We don't know. It hasn't been addressed.
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Old Oct 22 2009, 03:04 AM   #21
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Default Re: Flying a dragon: how high can you go?

I've started a story (which one day I will finish!) including just such a scenario - I've guessed that thread would become darker due to the moisture and more difficult to fight, as you can't easily tell which ones are fully drowned and which will still have enough life in them to cause damage on the ground.

Ah, time. Where does it go?
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Old Oct 22 2009, 07:31 AM   #22
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Default Re: Flying a dragon: how high can you go?

I've got one on the go too with a thread fight in a tropical storm.

Likewise; I MUST finish it.
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Old Oct 22 2009, 11:31 AM   #23
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Default Re: Flying a dragon: how high can you go?

Electric Dragon - it has been addressed. I think it's in Dragonsdawn, when they're scrambling to defend against Thread, and hear that one big squall drowned swaths of Thread.
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Old Oct 22 2009, 11:28 PM   #24
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Default Re: Flying a dragon: how high can you go?

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Electric Dragon - it has been addressed. I think it's in Dragonsdawn, when they're scrambling to defend against Thread, and hear that one big squall drowned swaths of Thread.
Was the implication that it drowned in the puddles of rain, or in the moisture of the clouds as it passed through? IIRC, I believe it was in the puddles and the driving rain. I'm not talking about that. I'm talking about fog from the deck to pressure altitude.
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Old Oct 22 2009, 11:29 PM   #25
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I've got one on the go too with a thread fight in a tropical storm.

Likewise; I MUST finish it.
With all due respect for your creative effort, alas, it is not canon.
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Old Oct 23 2009, 02:02 AM   #26
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Default Re: Flying a dragon: how high can you go?

I just had some triger, in Moreta, she hope the fog well lift, the day after the Gather, for dragons can see in it, but their rider are unable to, also the can share images, for it told during the Fall after.

Also there is something about the hight in DE/RSR on hights, for when they get to the first meeting place, the air is very cold, and the scarf don't help bring in warmer air, the only warm places are were the rider is sitting on his dragon.

Also SoP the 10 pattern, there is a discription of the clouds, sea, and the way the wings are set up.

Hope it helps.
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Old Oct 23 2009, 04:24 AM   #27
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Default Re: Flying a dragon: how high can you go?

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Was the implication that it drowned in the puddles of rain, or in the moisture of the clouds as it passed through? IIRC, I believe it was in the puddles and the driving rain. I'm not talking about that. I'm talking about fog from the deck to pressure altitude.
Okay, here's the answer.

It's not pretty!



Rainfall vs. Thread


We know Thread drowns in water, and that heavy squalls can be equally effective as a good-sized puddle. What about other weather systems?


Wikipedia lists the following rainfall precipitation rates:

Quote:
Originally Posted by Wikipedia
When classified according to the rate of precipitation, rain can be divided into:

* Very light rain — when the precipitation rate is < 0.25 mm/hour
* Light rain — when the precipitation rate is between 0.25 mm/hour - 1.0 mm/hour
* Moderate rain — when the precipitation rate is between 1.0 mm/hour - 4.0 mm/hour
* Heavy rain — when the precipitation rate is between 4.0 mm/hour - 16.0 mm/hour
* Very heavy rain — when the precipitation rate is between 16.0 mm/hour - 50 mm/hour
* Extreme rain — when the precipitation rate is > 50.0 mm/hour
Let's take 20mm/hour as the criterion for a heavy squall.

We also need to consider the terminal velocity of rain - this is typically between 2-9m/s.



For the selected rainfall rate of 20mm/hour, in one second, a depth of 0.0056mm of rain will hit the ground averaged out over a unit area of one square metre. That amount of rain exists in a volume of 2-9 cubic meters as it's falling, so the total volume of rain in the air is typically 2.8e-6m^3 to 0.6e-6m^3 in a unit cubic meter volume of the air.

Let's take a typical value from this of 1.0e-6m^3 of water per unit volume as being sufficient to drown Thread.

Note - this number isn't directly comparable to the volume of water required for Thread to drown in a puddle on the ground, as the rain acts over the whole length of time that Thread is falling through it.

What about clouds? Let's look at the Liquid Water Content. For ED's problem, fog has 5.0e-5kg/m^3. 1kg of water has an equivalent volume of 1e-3 cubic meters, so the volume of water suspended in a unit volume of fog is 5.0e-8m^3. For heavy, rain-bearing cloud, the mass of water per unit volume is 1.0e-3kg/m^3, or an equivalent volume of water of 1.0e-6m^3 per unit volume of air.

That's nice. It's the same volume of water as for a patch of air under a heavy shower. Always good when things agree without any need for fudging!

So... what's the difference between these two scenarios, fog vs. heavy rain? Well, it's a factor of 20. If you want the moisture content of fog to kill off Thread, you need the Thread to spend longer in those conditions by the same factor. At a VERY bare minimum, let's say Thread can drown in a storm extending over only 100m in altitude, but realistically we probably need a full kilometer of column. Can we get 2km of fog? What about 20km?

Well, we could get the former. Low clouds easily manage an altitude of 2km, and you can get fog extending right the way down.

4km? Well, you've gone well past the safe altitude for functioning effectively for long periods. Not gonna happen.

20km? Nuh-uh. High clouds typically give up at ~15km.


In conclusion: While a good strong storm or a cloud can drown Thread, fog isn't going to cut it, by probably a factor of 10 too little moisture in the air. And if the dragons can't fly, it's bad luck Holders!


How could the Pernese address these issues?

First, fighting in the clouds. The dragons are known to have a superlative sense of where they are spatially relative to other dragons. Your visibility may be atrocious for spotting Thread itself, but if you have to try... it'd be very, very nasty work, but dragonmen must fly and all that.

Second, fighting on the ground. The ability of Thread to devour organic material may be diminished briefly - though once it starts consuming material and growing, that initial advantage may be lost very fast. Holders and dragons tracking the trailing edge might be able to destroy burrowed Thread before it completely obliterates the ecosystem in the corridor... though fighting it as it falls would be sheer madness.

Third, you just don't build or plant in areas prone to severe fog.
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Old Oct 23 2009, 04:47 AM   #28
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I think Wiki MAY be wrong (again?)

The design load for rainfall systems in the UK USED to be that they had to cope with a rainfall of 75mm/hr lasting for 20mins (ie 25mm total). For the last some years this has been increased to 100mm/hr (again lasting for 20mins).

Both of these are well out of Wiki's table. Monsoon rains (and those in other tropical storms) far outweigh this.

To bring in another 'thread' to this ..... while direct flame will crisp a thread; is there sufficient heat in a (very) near miss to do the job? Or does heat disperse too quickly?

Or, perhaps Kitti Ping should have designed for dragons exhaling ice?
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Old Oct 23 2009, 05:02 AM   #29
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I think Wiki MAY be wrong (again?)
Yeah, always take their stuff with a pinch of salt. Still, it's good for ball-park estimates where it's not worth the bother of getting the One! True! Answer!

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The design load for rainfall systems in the UK USED to be that they had to cope with a rainfall of 75mm/hr lasting for 20mins (ie 25mm total). For the last some years this has been increased to 100mm/hr (again lasting for 20mins).

Both of these are well out of Wiki's table. Monsoon rains (and those in other tropical storms) far outweigh this.
Note the upper-limit category in that table is greater than 50mm/hr. I chose a lower value of 20mm/hr as a plausible cut-off, but it doesn't invalidate the whole argument. If Thread can only be drowned in rainfall of a factor of up to five times heavier than the value I chose, then it simply worsens the requirements for drowning it in any-old moisture by the same amount...

In other words, if you need rain falling at a rate of 100mm/hr in order to drown it effectively, mere fog really isn't going to bother it in the slightest...

Quote:
To bring in another 'thread' to this ..... while direct flame will crisp a thread; is there sufficient heat in a (very) near miss to do the job? Or does heat disperse too quickly?
Gaah. Stand close to a bonfire. You'd be dealing with radiant energy, and it really wouldn't be anywhere near effective enough. For that to work, dragonfire would need to be SERIOUSLY hot, and then you'd get cooked dragon as well as cooked Thread!!!


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Or, perhaps Kitti Ping should have designed for dragons exhaling ice?
Those pesky third laws of thermodynamics... I would NOT want to be the dragon absorbing enough heat in my body to generate that much cold!
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Old Oct 23 2009, 11:03 AM   #30
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Default Re: Flying a dragon: how high can you go?

you would need ice out of one end and fire out of the other to keep things in balance.

Not sure which way round would be worse!
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Old Oct 26 2009, 12:56 AM   #31
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Default Re: Flying a dragon: how high can you go?

About the rain - my impression was that the storm involved sheets of rain which drowned some thread as it fell. I'll have to find that quote...
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Old Nov 11 2009, 03:29 AM   #32
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<sinp>
Gaah. Stand close to a bonfire. You'd be dealing with radiant energy, and it really wouldn't be anywhere near effective enough. For that to work, dragonfire would need to be SERIOUSLY hot, and then you'd get cooked dragon as well as cooked Thread!!!
Those pesky third laws of thermodynamics... I would NOT want to be the dragon absorbing enough heat in my body to generate that much cold!
The cold effected the riders more than they dragons. Also why they were spaces out in a wing too.
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Old Nov 15 2009, 11:57 PM   #33
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Default Re: Flying a dragon: how high can you go?

I found the place in Dragonsdawn where it talks about rain having a significant effect on Threadfall. It is when they are still reeling from the first Fall, and trying to track where it will be falling next; it's soon after they give Tubberman the "captive" thread to burn. They are flying to Sadrid to bring what help and flamethrowers they can.

This is from my UK edition.

Quote:
"It was the wind," Wade Lorenzo told the rescue team. "The wind saved us, and the squall. Came down in sheets but it was water, not thread.
Quote:
"Why, it just cuts off," Bay said, surprised.
"Rain, I think," Pol remarked as he, too, craned his neck to see out the siliplex canopy.
Quote:
Then his eyes were caught by the circles of destruction, so hideously apparent from the air, interspersed with untouched swathes where squally rain had drowned thread before it could reach the surface.
Quote:
"You can watch vegetation disintegrating by the yard," Bay said anxiously. "Rain isn't enough."
Quote:
Pol and Bay had followed diligently after the flamethrower teams, taking notes on the pattern of the stuff, grateful that the squall activity had somewhat limited its destruction.
Obviously it would have to be a hurricane to completely drown Thread while it was falling, but I would imagine any amount of rain would weaken it somewhat, and a fairly hard rain would have a noticeable impact.

Now I'm wondering how much effect Threadfall would have on the weather itself?
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Old Nov 16 2009, 05:00 AM   #34
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Default Re: Flying a dragon: how high can you go?

I don't see that thread would affect the weather. When falling it is inert and therefore unable to affect the weather immediately around it OR the overall weather patterns.
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