Helicopter underslung mission

[ashkash]

What are the advantages of having a load indication system that can display your underslung load to you in the cockpit?What I mean is that even though more information never hurt anyone, but is that information very useful in light helicopter with max underslung capacity in the 1.5 ton regime. Is there anyone out there who has utilised such a system and tell me its pluses and minuses?

[minigundiplomat]

very useful in light helicopter with max underslung capacity in the 1.5 ton regime.


That'll be someone at Benson then.....

[Saint Jack]

Ashkash, An external load weight indication system can be extremely useful in circumstances, for example, where the personnel preparing a load are 'non-helicopter' and not aware of the the weight limitations or have no means to weigh a load except by 'best guesstimatin' etc. Also, these personnel may not be aware of the flight charactaristics of 'high-density' and 'low-density' external loads. I once witnessed a knock-down, drag-out argument between a pilot and a building contractor because the pilot refused to undersling a sheet of plywood.

Over the years I have come across a couple of systems, if I remember correctly they were manufactured by a) Chadwick Inc, and b) Onboard Weighing Systems Inc.

The only 'minus' of such a system that I can think of is a) it adds weight to the helicopter, but not a lot, in a situation where helicopter minimum weight is very important, and b) the systen will require periodic calibration and maintenance.

[jayteeto]

The RAF use such a system, its called a crewman.

[Always a Sapper]

Tells you when it's fallen off..... :ok:

[Bluestar51]

I always had a lot of luck using the torque meter.

Bill

[TheWizard]

The load cell is actually useful to tell you that the "1000 Kg" load that you have been assured has been carefully worked out and weighed is actually more like three times that weight, allowing you to gently place it back on the ground for adjustment!
That and the torque figures rapidly rising through the scale as you try to pull in power!! :\

[Two's in]

The Army did Lynx underslung night trials with a Bowser "weight on wheels" system at Otterburn some years back IIRC.

[vecvechookattack]

Ashkash, An external load weight indication system can be extremely useful in circumstances, for example, where the personnel preparing a load are 'non-helicopter' and not aware of the the weight limitations or have no means to weigh a load except by 'best guesstimatin' etc. Also, these personnel may not be aware of the flight charactaristics of 'high-density' and 'low-density' external loads. I once witnessed a knock-down, drag-out argument between a pilot and a building contractor because the pilot refused to undersling a sheet of plywood.


Saint Jack. That would never happen in the British Armed forces. All personnel who are responsible for preparing loads are highly trained and have to be qualified to conduct load preparation.

[MightyGem]

...and they NEVER make mistakes. :rolleyes:

[ShyTorque]

The military Puma has a collective pitch gauge, rather than a torquemeter.

We also had a theoretical collective pitch graph, from which we could get a good idea of the AUW of the aircraft before and after load pick up and cross check the usl's weight.

[piggybank]

Ref Saint Jacks comments, and others. I have rarely seen a medium helicopter (if it picks up one and a half ton on the hook its not a lighty any more) that does not have a weigh cell fitted.

The chances of the people loading the nets getting the weight right is slim, and when you are at the limits of what you can lift for a trip the weight information is indispensible.

[The Nr Fairy]

So what torque did MA get to when he tried to sling load Germany ?

Heard about the story second hand, would like to know more. Last heard of MA about 4 years ago, ill having contracted a disease through drum skins. Anyone know if he's ok now ?

[tonker]

You could always just buy an aircraft that was engineered to do the job...


YouTube - Amazing Russian Mi-26 Helicopter (http://www.youtube.com/watch?v=yo0TMDP6vIQ)

[oldbeefer]

The main benefit of such a system - along with suitable mirrors - is that it dispenses with the need for a (usually very heavy and overpaid) crewman who thinks it's his God given right to talk all the time (even when not required).

[minigundiplomat]

The main benefit of UAV's - without the need for suitable mirrors - is that it dispenses with the need for a (usually very heavy and overpaid) Pilot who thinks it's his God given right to talk all the time (even when not required).

Bring em on!

[TheWizard]

Don't forget one of the benefits of UAVs is that said Crewman can do said pilots job just as easily.:ok:

[Fareastdriver]

The weight that a load indicator may show you can be subject to innumeral variations. There are two types, Those that show a second pilot or crewman what the actual weight is or the one you set and it tells you when you have gone over the figure. Neither are very accurate even though their actual weight indication is correct.

When you are in the initial stages it will indicate the increasing weight of the slinging gear as it comes off the ground. To pull the load off the ground requires the overcoming of inertia and in the hover the effect on the rotor wash on the load will falsify the figure. Transitioning to forward flight incorporates another batch of inertia and it also requires energy to pull it through the air. Aerodynamic effects dependant of the shape of the load may reduce or increase its apparant weight. The result is that you will be informed of an actual weight that may bear no relation to the planned weight.

One example. Lifting a bridge structure and positioning it. Actual weight 1725 kilos including plywood fins to ensure that it flies fore/aft in relation to the aircraft otherwise it was going nowhere. Continuous reading loadmeter indicates approx 1970 kilo in the hover then slowly down to 1800 at 45 knots. At 60 knots rapidly decreases down to 900 kilos as it starts flying. Continue at 50 knots/1650.

Another. Resupplying an island 125n.m. away in the Solomon Islands with a 332L. A heavy aircraft permantly fitted with internal overload and sponson tanks. Rations for a week for Australian police plus five drums of diesel in a net. The weight on the hook doesn't matter, it well within the limits but when you hook up you are at 20,000 lbs. Then you can lift the load and are at minimum fuel to get there and back. One slight inconvenience is that it is at +35C and ten miles south there is a mountain range over 5000ft. high that you have to cross to get to this island. There are valleys but there also permanent 8/8th cloud. No load guages on this but at 7,000ft/70knots it stops climbing. It is down to 18,500lbs in weight so it should still be soaring but the drag on the load is sufficient stop it. Once over the hill descending to 2,000ft at 15 degrees of pitch should give you 130knots. No chance, 90 at the best.

My only recommendation for a load guage would be to bin it. Ignorance is bliss.

[minigundiplomat]

Ignorance is bliss.


There is a lot to be said for being fat, dumb and happy. :)

[Mmmmnice]

I'd never call my crewman fat MGD - unless he was of course!!

[ashkash]

thanks everyone. This is valuable. My concern is that if I have a torque gauge and an on board computer telling me what i should be hovering at, what use is the load cell. My Go/No Go will always be my torque meter.If my load cell says I have 1.8 tons while my hover calculations show that it is 1.2 ton, which would I believe? Isnt it just an added complexity for information that adds very little value to the mission? Has this load indication proven so valuable to anyone that he would not do without it? Are there people out there who have this system but could not care less if it was not there?

[ashkash]

thanks SJ. Doesnt this utilisation reduce the helicopter to the status of a weighing machine? Doesnt the torque gauge give you the same answer- with deeper implications on flight safety?

[FireAxe]

At least you can then tell the hookers by how much they have miscalculated the load weight.:ok:

[Saint Jack]

Ashkash: Some may say that the fitment of an external load weighing system does indeed "..reduce the helicopter to the status of a weighing machine?" But when you need to know the weight of a load and have no other means of dertermining what it is, then.......

"Doesnt the torque gauge give you the same answer- with deeper implications on flight safety?" Absolutely yes, but here you seem to be assuming that external load work always takes place at MTOWA (for external loads), this is usually the case, but not always. If you're operating at less than MTOWA and still need to know the weight of the load, how are you going to achieve this? Remember, as the pilot you're required by law to know the weight of your aircraft at take-off (I'm assuming, from the subject of your post, that you're a civil pilot with a commercial operator).

As others have said, an external load weighing systems has its limitations, especially with large-area loads in the down-wash, and these must be understood when using such a system.

Perhaps if you would fully explain exactly what you're task is then we all can help you to achieve it in a safe and professional manner.

[tantalite]

Hi Ashkash,


I worked with HAL to develop and supply the underslung load measuring equipment (LME) for the ALH/Dhruv that they finally bought.
The idea was to give pilots a fairly accurate indication of the load being attached to the airframe. In high altitude operations I would imagine that the pilot would wish to have confidence that he was not being asked to lift more than the recommended load. The pilot has the ultimate responsibility for the aircraft, as a pilot myself and being ex RAF, I feel I would not rely or trust completely anybody on the ground to ensure I was not overweight as they would probably not be facing the BOI in the event of any 'incident'.

[tantalite]

Yes it does make it a weighing machine but that is essential in commercial operations when charging for the actual load carried.

[its the bish]

Co-incidental to this thread, I see that the NOTAMs for tomorrow (26th March) show 6 Merlins going from Benson - Yeovilton with underslung loads !

[Hempy]

Hopefully it turns out better than the Searey lift off of Lake Eyre :ok:
http://i1291.photobucket.com/albums/b550/Carling113/eyre9_zpsdn7sengh.jpg
https://fbcdn-sphotos-h-a.akamaihd.net/hphotos-ak-xpf1/v/t1.0-9/10172847_802560979827902_7381422967765940491_n.jpg?oh=e8e833 c8ecaf934c82439456cf98f0e4&oe=55B3DF22&__gda__=1437638472_197f3548d7d19212de1442a1e5b48622

[Old-Duffer]

Picture this - island off Borneo and Army wants a load of ammo moved to Tawau using a Beverly.

RAF Movements Officer accepts the load as offered by those nice Army mates and duly loads the stuff into the lower deck of Blackburn's finest.

The take-off roll should have given a clue that all was not well and the aircraft, having used up almost every inch of the runway, staggers into the sky and climbs straight ahead. The transmissions between the aircraft captain and ATC are quite interesting and the captain decides that he won't take the direct route over the hills to Tawau but will rather fly all the way around the coast. At the other end a precautionary overweight landing ensues before the load is check weighed.

The 'back' calculations confirm that the Beverly got airborne at 7000 lbs over max auw.

Accepting loads from anybody, without an assurance of its true weight is as close to a fatal game of liar dice as one can get.

Mind you the Movements Officer had 'previous'. He and I were on the same officers' course, when he put several rounds from a sten gun over the range wall!!!

O-D

[Roadster280]

When I was doing the "ground party" bit on MAOTs, it was noticeable that I never, ever, saw a set of scales issued for weighing loads!

There were the concrete drums at Upavon with weights marked on them, and of course JATE had schemes for just about anything to be underslung (or tied down). But they can only be estimations of the "normal weight" of say a Land Rover.

Away from the RAF, back in my own Corps, I can tell you that a "normal" FFR Land Rover can have one radio/piece of comms kit, or 10. Each weighing 50lbs or more. Tanks full or tanks empty. Trailer full of mast kits, fuel, water, tentage etc - very heavy. Trailer full of tables & chairs - not so much. I can easily see an underslung FFR Land Rover and trailer varying by 1000 lbs. I can't recall if the JATE scheme allowed for this, but I would be surprised if it did.

[NutLoose]

I watched to odd episode of Ax Men and the ability to weigh the load appeared to be very useful, as they lifted the trees out of the forest they were able to accurately come up with a weight and thus value each tree, along with ensuring they could lift it ok in the first place.

[dragartist]

Ash,
Clearly a serious question but mixed response as usual. Thatz PRuNe!


Try the link to Onboard Systems


ONBOARD SYSTEMS | Home (http://www.onboardsystems.com/)


They have a UK Office in East Sussex.


I am not sure if Breeze Eastern are also in the game.


I have no vested interest in either (they may have given me a pen or a LED torch at an exhibition)


On the UAV front, Kaman did some work with the K Max with the US Army which was autonomous. did away with fat noisy aircrew of both persuasions altogether. Not sure if I am allowed to post the data as I have not seen it in the public domain.


JATE certainly were/are the centre of excellence for such stuff in the UK. I think Onboard and Drallim Industries took on Design Authority for some of the JATE designed kit.

[NutLoose]

Drag, if you look, this thread originated back in 2010!

One thinks he will have sorted it by now. :)

[dragartist]

Thanx Nutty, looks Like I am not alone! I am enjoying another thread on over flights going back years as well! Another topic I know FA about.
Cheers
Drag

[DITYIWAHP]

Who needs a winchman / gadgets etc when you have years of experience and the knowledge that you haven't crashed (yet?)?

08K_aEajzNA

[charliegolf]

No, no, no- she can only do that BECAUSE she has a crewman.:=

CG

[Fareastdriver]

Years and years ago when Aldershot had some industry a factory was built with the normal tall chimney. This was a brick built structure with a large fabricated brass ring at the apex. Time marched on; the factory became redundant and eventually became to being demolished. The chimney would normally have been felled to cheers from onlookers but the Army had sensitive communication systems close by so the crump of a thousand tons of brickwork hitting the ground was considered unacceptable. As a result it was going to have to be dismantled brick by brick but the brass ring was a problem.

This is where the RAF stepped in.

The ring was estimated at about 1,500 lbs, well within the capability of a Puma. To facilitate its release from its mortar bed the brickwork was chipped away so that there were only four small pillars supporting it. Access for the crewman who was going to hook it up was provided by the scaffolding built within the chimney itself. The plan was, the crewman would nip up the chimney supervised by demolition staff, hook the already rigged ring on to the Puma’s hook, there then would be a pause whilst the crewman and staff shinned down the chimney and out of the firebox and finally the Puma would lift the ring and place it inside an adjacent skip.

The squadron commander was soon to hand over the squadron so he decided to take on this task. He considered that he was probably not the most experienced USL pilot on the squadron so he had the most proficient in the left hand seat flying shotgun.

The bewitching hour came and off we went.

The aircraft landed and we confirmed the final details with the organisers and waited until we got the signal from our crewman at the top of the chimney. Despite his lack of practise the boss had no problem positioning the aircraft at an 80 ft. hover with little outside references. The aircraft crewman was pattering away and came the time where it was hooked up and we were waiting for everybody to clear the structure.

Then one of the pillars started collapsing.

This was probably a result of the vibrations from the aircraft as the hover was steady enough. The hooker and his support staff were now fleeing down the chimney hotly pursued by bricks and rubble from the collapsing pillars. It was then that it was apparent that the estimated weight of the ring was hopelessly optimistic and full power was only just holding it in position. It couldn’t be jettisoned because it would have brought down the whole chimney and everybody in it. We listened to the helicopter crewman’s commentary until we heard him declare that they were out of the chimney and clear.

It was then dragged off sideways. As soon as it cleared everything started descending and with a combination of luck and skill the boss plonked it into the skip.

[WASALOADIE]

Back in the mid-late 80's on the good old Mk1 Chinook, 3 aircraft were fitted with HODR's so that fatigue could be monitored and data collected for future use.

Each of these a/c had strain gauges on the cargo hooks as part of the fit, among a plethora of other sensors, accelerometers and transducers.

it soon came to light, that, nets with 6 pallets of simulated Ammunition (simmo) that were supposed to weight within the 6800Kg limit, did in actual fact weigh considerably more due to the fact that the sand within had become very wet. Only after removing 2 pallets from each net were we able to lift said pallets, resulting in more nets being required for the job so that we could lift on multiple hooks. The weight for 6 pallets turned out to be just over 8000Kgs.

We also found that, in the Falklands, trying to lift a half-ISO container of sand from a beach, we could only lift the container and approx 3000Kgs of sand due to the suction created under the container on the beach.

As the aircraft transitioned, there was an increase of up to 25% of weight until the transition ceased and we were at constant forward speed.

We also had one case of lbs being converted to Kgs on a load that was supposed to weigh only 9000lbs when in fact it actually weight just under 9000Kgs! Within the capacity of the Chinook, but not with full fuel at the time!

So whilst strain gauges / load cells are accurate, they opened up a can of worm regarding accuracy of weighing systems on the ground.

Prior to these events, we had been applying torque (up to 88% dual engine IIRC or 98% Mast Torque). Within the aircraft limitations but potentially exceeding the rigging equipment limits.

[Unchecked]

Merlin has a fairly decent load weight display on its CCU (computer gizmo thingy). This came in handy once at the Bastion load park when attempting to lift a supposed 1 ton load which weighed in at over 5 tons, putting the account 2.5 tons over MAUW.

Another handy bit of kit was FLIR. Swivelling it 180° allowed the front enders to monitor the load and the crewmen could man the guns while transiting over bad lands.

[ShyTorque]

Ah, "SIMMO"!

I recall a multiple aircraft, night lift where the problem was caused by the underslung loads of "SIMMO" being too light, rather than (the usual) too heavy.

The loads ("cleared loads" courtesy of JATE) were prepared as per the AP1105, Carriage of USLs manual). However, whoever prepared these loads (Army) failed to realise that the boxes should have been ballasted to their normal weight, rather than left empty for training.

About five Pumas arrived at the remote load pickup point, with the correct (reduced) fuel load to take the first load. The Puma HC1 was usually short of fuel even when it took off with full tanks, so this put us on the back foot to start with.

As we took off with our first load we realised that the weight was considerably less than expected, so much so that it would only fly at about 55 - 60kts before it became totally unstable (should have been about double that, IIRC). Problem was, there was a very strong headwind and at one stage we had less than 20 kts groundspeed!

Were supposed to shuttle three loads each. From comments on the RT it was obvious that everyone else was having a similar problem. I think we were one of only two crews that were brave (or stupid) enough to go back for the third one. Aircraft were dropping out of the task and diverting left and right due to fuel shortage. We all landed with fuel low lights on. A bit of a shambles all round but good character building stuff.

[Old-Duffer]

In the 1960s, it seemed as though only people called Price served in rotary wing sqns of the RAF. There was Henry Trevor, John Willy and finally 'Bathroom Scales' Price.

This enterprising officer commanded 103 in Cyprus when they were equipped with the Sycamore HR14.

Bathroom Scales was ever mindful of the poor hot and high capabilities of the Sycamore and sought ways to maximise payload wherever possible. He quickly identified that using standard weights for squaddies was wasteful at one end of the spectrum and possibly dangerous at the other. In consequence, he acquired a set of scales to be carried in each aircraft and soldiers were weighed individually with the kit they presented themselves with at the aircraft. He soon found that he could increase the number of troops carried and hence the movement of troops became a swifter and more effective operation.

Hence the nickname by which he was known ever after.

O-D

[kintyred]

ShyTorque,

You were lucky to be let loose with the simmo. In my day Pumas were used to recover the nets once the Chinooks had delivered the goods!

[ShyTorque]

ShyTorque,
You were lucky to be let loose with the simmo. In my day Pumas were used to recover the nets once the Chinooks had delivered the goods!

In my day, Chinooks weren't initially on the RAF's inventory and when they finally arrived they spent much of their time sitting in fields waiting for rectification after suffering various chip lights and hydraulic leaks.

[kintyred]

Yes ShyTorque,

I did a lot of that too.....and trying to dodge heavy showers which you knew would lead to spurious oil level captions!