S-92 Underslung Load Q:
I think it's because the load is taken by the fuselage structure, unlike some types where a panel can be removed from the floor and the hook attached to the MGB itself. I recall that the hook itself has a limit of 10,000 lbs, but I'm a bit rusty these days!
What makes you think its a structural issue?
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A 10,000 lb hook attached to an 8000 lb capable structure?
Sounds about right.
Sounds about right.
I would say the reverse. The 'tested' bit is on the airframe - not the hook itself. The hook will be rated to 10,000 lbs by its (third party) OEM and Sikorsky will have looked at the market to find suitable hooks that would allow the aircraft to carry 8,000 lbs as a design load maximum. I can't recall which OEM they use, but I see, for example, that Breeze Eastern market a hook with a 9,000 lbs limit, so that would be a good example of a suitable fit. Dart market hooks with a 25,000lbs rating, which would be overkill and unnecessarily heavy/bulky.
Avoid imitations
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It might be a legacy from the Blackhawk, which had an 8,000 lb hook upgradable to 9,000 lb.
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Is it possible that it is a dynamics of flight, flight controls and/or handling limitation? Such things might have an impact on the certified limits for the carriage of underslung load. In some cases flight test and evaluation may be the only obstacle to increasing such a limitation. A costly process that someone will have to pay for.
As I recall, the aircraft cargo hook design load includes a 2.5 G factor. Thats a number I definitely recall from the UH-60. The 92 will have the appropriate FAA requirement and that may include some variation that I cannot at the moment recall. Trying to check with someone.
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There is a organization in Canada that utilizes the hook. Mainly to carry out flaretip changeouts and other jobs at times (although no frequent)
Regarding weights each A/C and manufacturer are quite different. Let's take a quick look at various types:
BH06 / BH47 - both have hook attached directly and only to belly. The 206 would never have the power to do any damage to airframe. The 407 is similar but the weight permitted is quite low compared to what the AC could possbily pull and you end up running in to MTOW way early.
BO105 is attached to four points on the airframe. It is acutually attached to the undercarriage if memory serves and the load is shared between each stanchion in the airframe. (The BowCow would never have enough power to damage any structure believe me)
AS332 - Here is a different system which utulized two points of hook loading. The first is that the hook may be attached directly to the airframes underbelly but has a load 60% lower then the the prefered way. The most common way is that the hook is attached to a "stripper pole". The pole is attached directly to the bottom structure of the main gearbox and down though through a hole in the floor. Similar idea as that of the 212.
Regarding longline with either of these airframes maybe my prefered AC was the 92 at times. It was a extremely stable AC to work.
Regarding weights each A/C and manufacturer are quite different. Let's take a quick look at various types:
BH06 / BH47 - both have hook attached directly and only to belly. The 206 would never have the power to do any damage to airframe. The 407 is similar but the weight permitted is quite low compared to what the AC could possbily pull and you end up running in to MTOW way early.
BO105 is attached to four points on the airframe. It is acutually attached to the undercarriage if memory serves and the load is shared between each stanchion in the airframe. (The BowCow would never have enough power to damage any structure believe me)
AS332 - Here is a different system which utulized two points of hook loading. The first is that the hook may be attached directly to the airframes underbelly but has a load 60% lower then the the prefered way. The most common way is that the hook is attached to a "stripper pole". The pole is attached directly to the bottom structure of the main gearbox and down though through a hole in the floor. Similar idea as that of the 212.
Regarding longline with either of these airframes maybe my prefered AC was the 92 at times. It was a extremely stable AC to work.
As explained to me years ago, aircraft long line external cargo weight limits were determined by the airframe structural load path from the external load to the primary lifting structure. Not all airframes have a direct structural link to the primary lift structure which limit the amount of weight on the hook. There is also the reverse where some aircraft have a lower internal weight limit vs a higher external hook weight limit. In those cases the airframe structural limit can be the landing gear, floor loading limits, CG envelop issues, etc. As to the cargo hooks, it's been my experience that hook mfg'r tend to design/produce hooks to fit groups of aircraft models rather than one hook type for each model. Unless they get a specific OEM contract. So comparing a hook wt. limit to an aircraft external weight limit may not be an accurate comparison.
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Hey thanks for the comprehensive replies - has anyone here actually flown it with 8000lb on the hook? Looking at a potential Helitack operation - so kick out the troops then clip on the bucket on a long-line then go dipping.. with the 900 US Gal bucket and throw some water at the ground.
You may wish to review the restrictions on the use of Power by the Hour components and engines in external load operations. Many helicopters have STC's permitting even greater external load capacity than those specified by the OEM - the limitation is the combined weight of the equipped helicopter and external load, and the certified ambient performance. If these factors are combined it is possible to lift loads in excess of the certified hook weight with a light aircraft, at dawn, flown by racing snake flight crews and very little gas and still be within the certified external gross weight limitation for the aircraft. The increased gross weights permitted for external loads with helicopters are a function of the ability to instantly jettison the load and immediately reduce gross weight and perform all kinds of recovery manoeuvres in the event of a power loss in a multi-engine aircraft.
The increased gross weights permitted for external loads with helicopters are a function of the ability to instantly jettison the load and immediately reduce gross weight and perform all kinds of recovery manoeuvres in the event of a power loss in a multi-engine aircraft.
And i you do exceed the `certified` load limit of the hook,and there is an incident,you may well have to do the `awkward carpet -shuffle`,with no biscuits,in front of an audience.....
You may also reflect ,if you are so `cavalier` to limitations ,that they may well fail whilst someone else is driving.....
You may also reflect ,if you are so `cavalier` to limitations ,that they may well fail whilst someone else is driving.....
