Type 081 LHD

Totoro said:

So, you're saying that the widely qouted 495 km range figure is, in fact, achieved with little to no payload? And that with some useful payload (lets say 3 tons) that figure is reduced by ... how much?

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Any helicopter's stated range is often achieved with little to no payload, and under ideal conditions (no winds, low temperature, etc). When you run up into the max take off weight of the helicopter, for every kg of cargo onboard, another kg of fuel has to be offloaded. To carry 3 tons of cargo, one will have to offload 3 tons of fuel to stay under the max take off weight. The Mi-17 can carry 1360 litres of fuel internally, which works out to be 1092.08 kg. The empty weight of the Mi-17 is 7,370 kg. Max takeoff weight of the Mi-17 is 13,000 kg, under ideal conditions. However, normal takeoff weight is around 11,000 kg under ideal conditions, as the Mi-17 is notoriously known for being anemic in power in military circles. Furthermore, in order to ensure a return trip with reserves, the Mi-17 needs its external fuel tanks, which can carry a total of 1425 litres, or 1144.275 kg. Therefore, total fuel weight is 2236.355 kg, then add the empty weight of the aircraft. That adds up to 9606.355 kg. Add in the weight of the 3 crewmembers (each person weights roughly 75kg including weight of all equipment carried by each crewmembers), that works out to around 9800 kg. That means you have almost 1200 kg of cargo that can be carried under ideal conditions. Not a lot. In order to carry 3 tons, you will have to loose the external fuel tanks, which means the helicopter is on a one-way mission, as there is not enough fuel to account for reserves, emergency, and conditions (e.g. headwinds, poor weather, finding a open and undefended landing zone, loiter time, etc).

Don't forget to factor in that the local climate of the Taiwan Strait means that there are two openings in the weather (August to September and November to April) that will allow a invasion to proceed. High temperatures will cut into the payload of any helicopter significantly.

szbd said:

The standard payload of Mi17 is 4 tons (total take off weight 11 tons, empty weight 7 tons), and the range is 495km with internal fuel at this payload. This is enough to transport soldiers across the straight and back.

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Your assuming that jet fuel doesn't weight anything, and there is no pilot, co-pilot, and flight engineer. That helicopter ain't going anywhere.

Pointblank said:

Your assuming that jet fuel doesn't weight anything, and there is no pilot, co-pilot, and flight engineer. That helicopter ain't going anywhere.

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The maximum internal payload of Mi17 is 4 tons. That includes full fuel, pilots, and full of soldiers, and the range under this condition is 495km. The total maximum payload is 7 tons, with 4 tons inside and 3 tons outside.

szbd said:

The maximum internal payload of Mi17 is 4 tons. That includes full fuel, pilots, and full of soldiers, and the range under this condition is 495km. The total maximum payload is 7 tons, with 4 tons inside and 3 tons outside.

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I just explained in detail why that is impossible;

The Mi-17 can carry 1360 litres of fuel internally, which works out to be 1092.08 kg.

The empty weight of the Mi-17 is 7,370 kg.

Max takeoff weight of the Mi-17 is 13,000 kg, under ideal conditions.

However, normal takeoff weight is around 11,000 kg under ideal conditions, as the Mi-17 is notoriously known for being anemic in power in military circles.

Furthermore, in order to ensure a return trip with reserves, the Mi-17 needs its external fuel tanks, which can carry a total of 1425 litres, or 1144.275 kg.

Therefore, total fuel weight is 2236.355 kg, then add the empty weight of the aircraft. That adds up to 9606.355 kg.

Add in the weight of the 3 crewmembers (each person weights roughly 75kg including weight of all equipment carried by each crewmembers), that works out to around 9800 kg.

Factor in that each soldier will be carrying as much equipment and ammunition as they can physically carry, you aren't carrying many soldiers.

Yeah I saw that. But At 11,000 kg, Mi17 can fly 495km with 1360L fuel, without external fuel tanks. Therefore you have about 2200-2300 to carry soldiers, enough for 25 persons with gears. Also, This is the data of base Mi17, for Mi17 V5 and V7, the power is much better.

szbd said:

The maximum internal payload of Mi17 is 4 tons. That includes full fuel, pilots, and full of soldiers, and the range under this condition is 495km. The total maximum payload is 7 tons, with 4 tons inside and 3 tons outside.

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lol, even J-10 carrying 4 ton of payload + fuel might not have a 500 km combat radius let alone Mi-17.

Read carefully, it's not combat radius, it's range. And not 4 tons of payload, but total 4 tons of payload including fuel.

szbd said:

Yeah I saw that. But At 11,000 kg, Mi17 can fly 495km with 1360L fuel, without external fuel tanks. Therefore you have about 2200-2300 to carry soldiers, enough for 25 persons with gears. Also, This is the data of base Mi17, for Mi17 V5 and V7, the power is much better.

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Under Ideal Conditions, that means no headwinds, you know exactly where you are going, you are traveling at a economical speed and altitude, you don't loiter to pick out a landing spot, good weather, and cold air for the engines and the blades to cut through. And warfare is never ideal. There may be strong headwinds en route which you have to battle through, the landing zone may be unsuitable for some reason, you might have to fly nap of the earth to avoid detection, which uses fuel excessively, etc, etc.

szbd said:

Read carefully, it's not combat radius, it's range. And not 4 tons of payload, but total 4 tons of payload including fuel.

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what's the point of stating that then? If you are talking strictly the amount of distance that it can travel, the 495 km might only translate to a 200 km combat radius, which makes this entire conversation worthless.

But that's also 495km, the shortest path accross Taiwan straight is only 130km. Also when the choper flying back, it only has <9000kg payload. At most, China can put some semi submersible ships in the straight, so some choppers can land on them and refuel.

tphuang said:

what's the point of stating that then? If you are talking strictly the amount of distance that it can travel, the 495 km might only translate to a 200 km combat radius, which makes this entire conversation worthless.

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200km combat radius maybe enough for Taiwan senario, that is my point. I always think landing in the north of Taiwan is a better choice. In this senario, PLA does not need an LHA that can take the choppers move to a far distance, just a platform in the straight to refuel, if necessary.