"SHARPSPEED" (SHARPSPEED)
04/16/2018 at 14:47 • Filed to: None
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"SHARPSPEED" (SHARPSPEED)
04/16/2018 at 14:47 • Filed to: None | 0
| 9 |
So I’m doing some digging into rigid airships. Specifically how much they could carry around. Because I’m not an aerospace engineer and, well, just an idiot, there’s some termology I’m not getting. I get terms like “lift capacity” and “payload”. I know what payload is, but lift capacity is the one that confuses me, and it doesn’t help that they use the same measurements, as per the wikipedia page fore the LZ 127 Graf Zeppelin: “The Graf Zeppelin had a total lift capacity of 87,000 kg (192,000 lb) with a usable payload of 15,000 kg (33,000 lb) on a 10,000 km (6,200 mi; 5,400 nmi) flight.” When I hear the word “lift” with anything that flies, I think of the force that allows said anything to fly. If it the same thing here? I remember hearing old airships weren’t capable of carrying much, but nearly 200K Ibs sounds awesome, actually. So what the hell is lift capacity and payload, considering I clearly don’t know?
Cé hé sin
> SHARPSPEED
04/16/2018 at 15:14 |
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In short, the lift capacity refers to the total weight being lifted - ship and payload.
ttyymmnn
> SHARPSPEED
04/16/2018 at 15:18 |
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When I hear the word “lift” with anything that flies, I think of the force that allows said anything to fly. If it the same thing here?
I’m not an engineer either, but my sense is that lift , as you refer to it here, pertains to a wing and the lift generated by the air passing over it. I would guess that the relative term for an airship would be buoyancy , since it get’s all its life from the gas bags.
BigBlock440
> SHARPSPEED
04/16/2018 at 15:22 |
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Lift capacity = GVWR
Payload is the same, GVWR - vehicle weight = how much it can carry
EngineerWithTools
> SHARPSPEED
04/16/2018 at 15:23 |
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Without digging into the details (hey, you get what you pay for on the interwebs), I expect that the “lift capacity” described here is how much upward force it can generate. For a winged aircraft, this is lift from the wing. For an airship, it’s basically buoyancy (some of the newer ones produce some aerodynamic lift as well, I believe). Just like in a winged craft, a bunch of this upward force must be spent just lifting the craft itself - most of it, actually. Whatever lift isn’t used in lifting the craft itself can be used for cargo / passengers / payload, and is the much lower number.
Smallbear wants a modern Syclone, local Maple Leafs spammer
> SHARPSPEED
04/16/2018 at 15:31 |
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I’d imagine Lift Capacity would be the total amount of lifting force generated by the (in this case, hydrogen) gas. Following that line, Payload would be the Lift Capacity minus the weight of the airship—all the structure, engines, skin, gasbags etc.
My guess is that Payload would be measured dry, ie without fuel and oil. 15,000kg sounds like a lot of payload for a vehicle that wasn’t exactly known for it’s carrying capacity, but as soon as you consider the flight duration and the size/quantity of the engines (iirc, in the case of the Graf, 5 Maybach V12's), the amount of fuel required would eat up a huge proportion of that.
Highlander-Datsuns are Forever
> SHARPSPEED
04/16/2018 at 15:37 |
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You would also need to consider how the airship caries the payload. While it may be capable of lifting more than 33,000 lbs that 33,000 lbs needs to sit somewhere and the air frame needs to be able to support it without failing. I guess this is why water based ships make so much more sense.
Maxima Speed
> SHARPSPEED
04/16/2018 at 15:46 |
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Total amount of weight that the hydrogen (or helium) can lift. This includes the Airship itself.
Eric @ opposite-lock.com
> Highlander-Datsuns are Forever
04/16/2018 at 17:00 |
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Vessels that float on water are doing the same thing, but water is far denser than our atmosphere, so you don’t need as elaborate, large, or light (which in turn means it is fairly delicate) a vessel.
gmporschenut also a fan of hondas
> SHARPSPEED
04/16/2018 at 21:53 |
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https://en.wikipedia.org/wiki/R101#Operational_history
http://www.airships.net/blog/british-airship-r101-crashes-killing-48-day-1930/
another thing is that with airship generating lift soley from their bouyancy, one wants a bit of excess in the event of a gas leak.