Max underslung load for helicopter(s)?

[ppheli]

A friend put a question to me which I can't resolve from my books or a web search. What is the heaviest thing which can be lifted by helicopter? Multiple helicopters allowed (eg. two Chinooks).

There is a practical reason for this which I can't go into yet, but suffice to say I think we ought to restrict it to "western" helicopters and rule out the Mi-26 - hence the Chinook example.

[roundwego]

Multiple helicopters allowed (eg. two Chinooks). ???

Give us a better clue. In theory a 100 tonne strip of metal could be lifted by multiple helicopters if the strip was long enough to line the helicopters up along it and they all lifted a section at once. Difficult to co-ordinate and manuevre but not impossible.

Are including military helicopters or limiting it to civilian ones?

[vorticey]

:rolleyes: :confused: :eek: LEAD!;) := :D :}

[FWA NATCA]

Max load slung under a helocopter is affected by various things such as temp, wind, fuel load, configuration, etc. with in my opinion temp being the largest factor.

I've lifted 3,000 lb with an H-46 on a cool day, and then seen on a hot day this same aircraft couldn't lift 2000 lb.

Mike

[sycamore]

Many years ago there was/maybe a trial in the US using 4 xH34 to lift aN " X" shaped rig which carried a load slung from the centre.Don`t know how successful it was ,but on the basis that no-one does it ,probably in the "too difficult/dangerous" category, especially for single-engined helos.
CH-47 can probably lift about 28000 lbs if the crew leave all the flak jackets and lunch-boxes behind!
It is also possible to lift a greater weight than from a hover by having your load on a flat-bed moving along at 20-30 mph,ie above trans.lift speed, if you were going to load it on a ship steaming along,otherwise you have to have another flat-bed at your destination-could be tricky!!;)

[ShyTorque]

I once flew Christopher Biggins as a passenger. Does that count? ;)

[ppheli]

So if one Chinook can hike up 28,000lb, does this translate into two Chinooks lifiting 56,000lb or do you have to deduct a little=?

Vorticey - yes, I'm on your wavelength but it was a dense answer to be honest :bored: I did have to check back to my original posting to see I had put "heaviest" and not "densest" just in case.... ;) ;) ;) ;)

Sycamore - you refer to the Piaseki experiment that later involvded an aerostat as part of the structure - now that was one big dream! Actually, my query is for an actual project in 2003 in UK, so that would limit it down a bit to what could be available.

[NickLappos]

The real lift prize goes to the Mi-12 which has about 50,000 kg of payload, and has taken 40,000 kg of payload internally to 3000 meters. I would believe its slung load is of that order of magnitude. To gauge this capability, the max gross weight of the CH-53E, the next largest operational helo, is 73500 lbs, so the Mi-12 has lifted more than the whole 53E! (edited by Nick to change to Mi-12. Brain fart originally had listed Mi-26, which has a 56000 kg MGW).

twin lift is a tricky game, Sikorsky used a spreader bar to connect two Skycranes once, in a limited demo. The control tasks are very hard to wrestle with, since the load, the bar and each helo has a natural motion. Sikorsky has perfected the control methods for this, using interconnected auto=pilots, but never used this in a practical way.

the lift of the two helos is less than the sum, since the helos pull slightly outward on the spreader, and the spreader has its own weight and vertical drag. A good working number is to guess that the losses are close to 10%, so a twin lift could probably lift 90% of the sum of the capability of the two machines.

The trials sycamore mentions were the Piasecki Heli-stat, which flew briefly about 15 years ago. It had the four S-58's (H-34's)permanently attached to a massive frame with their tail rotors disconnected. The controls were interconnected with cables so one pilot could control the whole shooting match, except for the throttles, which were manually controlled at each seat. The center of the helistat had a big gas bag that created enough lift to barely float the whole machine, so the rotor thrust was all free lift, about 50,000 lbs (4x13,000 lbs total).

The device was structurally unstable, and took itself apart as it lifted, with a horrendous twisting and thrashing. One pilot was killed in the crash, unfortunately.
http://avia.russian.ee/vertigo/piasecki_helistat-r.html

accident report:
http://www.ntsb.gov/ntsb/brief.asp?ev_id=20001213X34293&key=1

[46Driver]

We saw the MI-26's in Somalia - big freakin' machines. It made the 53E's look small. I don't know if it counts but Boeing made a couple of HLH (Heavy Lift Helicopters) back in the mid-70's. All up gross weight was around 144,000 lbs. (Being a Boeing, it was of course tandem rotor)

[NickLappos]

46Driver,

The power of PR is awesome. The HLH flew only in the Public Relations man's dreams. Never even came close to flying, in reality.

[[email protected]]

PPHeli - if all this is leading up to someone asking the RAF to perform a 2 heli USL with Chinooks for a PR stunt or similar, I suggest you forget it now and find out how much it will cost to hire a Sky Crane instead.

[46Driver]

I stand corrected. According to the info I just read, the airframe for the Boeing XCH-62 HLH was completed but it never flew due to transmission problems. The airframe is on display both at the Army Aviation Musuem and if I remember correctly is still displayed on the Boeing products poster. Hmmm, that poster also has the Osprey flying too.....