Whaley Bridge ballast

Maybe the slope causes problems, but being near to the ground or "in ground effect" increases the lifting capacity of helicpters.

SteveW

In article <qi98e6$1rsr$ snipped-for-privacy@gioia.aioe.org>, Bill Wright snipped-for-privacy@f2s.com writes

They're bloody big blades and whizz round pretty quickly.

In article snipped-for-privacy@4ax.com, Chris Hogg snipped-for-privacy@privacy.net writes

Lots of spray from the lake itself. Downthrust on any helicopter throws up a load of dust and small pebbles but a Chinook is just fierce.

I would think so. I guess the original problem was water getting under the concrete slabs and lifting them off rather than water coming through the dam itself. Therefore replace what has been washed away with these aggregate bags and then concrete over again.

I reckon helicopters are some of the most remarkable bits of mechanical engineering around. I used to know some of the guys at Imperial College and at Westland who worked on the design of the Lynx gearbox, which was a thing of true beauty. It is interesting how long the Sea King and Chinook have remained in service: once you get it right, you stick with the basic formula. I also knew the guy at Farnborough who figured out why the oil rig Chinook went down in the North Sea, once they had got the bits back to his lab.

I can never see a helicopter now without thinking of the (humorous) description of how they work in the famous after-dinner speech by Dave Gunson, an air-traffic controller: (I'm paraphrasing slightly) "You move the stick like crazy and you watch what happens - because if you want it to to that again, *that* is where you put the stick... It's a miracle a helicopter ever takes off: it should, of course, screw itself into the ground."

The biggest helicopter I've been in was as a passenger on the Penzance to Tresco (Isles of Scilly) service, a few years before it was discontinued. Bloody noisy, and the downdraught and hot exhaust fumes when it was idling during embarkation were quite incredible. But a hell of a lot quicker than going by ferry.

The only other times have been in "Treasure Hunt" size Agustas (ie pilot and front seat passenger, and bench seat for three rear seat passengers), as pleasure flights. The first time was at a classic car show in Bracknell and I got a very good view of the roof of the ICL building I worked in, and all the open fields between Bracknell and Wokingham. It was decidedly un-nerving when the pilot banked sharply (it felt as if he turned over with his right side parallel to the ground) and I had to convince myself that the door would *not* spontaneously open and that I would *not* fall out. The second time was at Oxford airport in a very plush helicopter with leather upholstery and deep-pile carpets, and I admired the pilot's skill in hovering about five feet off the ground, barely moving from one spot, as he was told to wait after he'd taken off until an aeroplane had landed so he could cross the runway (I think the ATC gave the helicopter permission to take off and cross, assuming that the aeroplane would land sooner than it actually did!).

I'm glad it was only *after* flying in helicopters that I read Jerry Grayson's account of how he managed to fly and land a helicopter with a failed tail rotor.

Yup one of my disappointments is that in spite of having designed large swathes of the software that runs all the comms and crypto in the EH101 Merlin, I never actually got to play with a real one.

... snipped

The only reason that helicopters can fly is that they are so ugly that the earth repels them :-)

Peanuts compared to the cost of the chinook, the national reslience highvolume pumps and the some what larger other pumps that have now been brought in, and the new road...

I'd expect them to be something similar to MOT1 ie a mix of stones down to dust. Packs together tightly.

removed

The bags may deteriorate when exposed to day light. The dumpy bags for the slate chippings started to have no strength after a year of exposure. The bags that the fire logs come do not noticeably weaken after several years.

I think they'll have to be removed, you don't know whats underneath or how well bedded they are. The concrete that they are pouring between them to stabilse the mass might present more of a problem.

See above...

If water had been getting through the dam in any appreachable quantity the dam would no longer be there. As you say water got between the slabs, washed out the earth behind them and they collapsed into the void.

I've seen pictures with 7 bags underneath the chinook.

A lot of air needs to be moved. Excellent flying as well, not only close to the dam but also hardly any lurch upwards when they drop a couple of bags...

Yers, BTDTGGTS. Army Air Corps Lynx "borrowed" by the BBC as a camera helicopter for the start of the Talls Ships race in the Solent. Quite an memorable trip:

The view of the grass through the side, was enhanced by the fact the door was locked open. Not quite sure how close the rotor tips were to the ground... That was leaving Southhampton Airport after refueling and dropping some tapes off.

Being an army pilot and there being rather a lot of other camera helos, links helos and fixed wing stuff flying about he decided to "keep away from all those bozos" and flew at 250 to 500' above the sea. Great views of the tall ships, yes over water with the door locked open. End up in the drink it would sink like a stone and you can't bail out until the rotor has stopped.

Out just past the needles and alarm sounds, pilot instantly puts the nose down, drops and heads straight for the mainland. Oil pressure warning light had come on. Pilot spinning up the rotor by losing height to get it closer to autogyro. Land is friendlier that water with the door off.

In article snipped-for-privacy@brightview.co.uk>, Jim K.. snipped-for-privacy@gmail.com writes

Not likely to need rebuilding. It is a very simple construction built before whacker plates were invented.

Yes I was amazed at how well the pilot was able to compensate the amount of lift as he let go of a ton of ballast. I wonder how much "autopilot" type assistance the pilot gets in maintaining a constant height as the load varies and if there are any gusts. Particularly critical when a pilot has to hover close to ground or close to a cliff face for a long time during a winch-man rescue of a patient. Probably there's less need for really accurate positioning with military Chinooks, but for air-sea rescue those guys need phenomenal reactions - and a lot of good feedback from an observer "forward one, right two, backwards one" (I wonder the units are - feet? metres?).

I have a lot of respect for helicopter pilots. I became quite good at "flying" various fixed-wing planes in MS Flight Simulator, but I never got the hang of "flying" a helicopter. Of course, "flying" in FS is no substitute for flying a real plane. I had a couple of lessons in a Cessna a long time ago, before a medical condition meant that flying was probably not a good idea, even if was still allowed by CAA, and the experience of feeling the plane pitch, roll and yaw as the controls were moved cannot be duplicated in a PC simulator! Nor can the mild vertigo when you look out of the window and think "it's a *long* way down" - even at only 500 feet. One thing that surprised me: we flew over a field where a farmer was muck-spreading, and I was amazed at how much of the smell made it up to 1000 or 1500 feet.

The helicopter G-BHXU that was used as the Skyrunner helicopter in Treasure Hunt ended up in a watery grave just off the Channel Islands when it suffered a catastrophic engine or gearbox failure, requiring the pilot to autogyro to the surface of the sea and then he and his passenger had to bail out. They were wearing lifejackets but the pilot said it would have been useful if the helicopter had had an oxygen supply (an optional extra on that chopper) to help them breathe until they could leave the cockpit which filled with water very quickly. I'm not sure whether they were flying it with the doors off. Because the wreckage couldn't be recovered, the exact cause was never determined.

F****ng major irony alert there, mate.

An interesting look on how you train for getting out of a helicopter that ditches at sea:

Not long after the "Army Lynx Experience" I did another job at a "dunk tank" probably at RNAS Yeovilton. Fortunately I wasn't required to participate in a dunk. Watching what happens was enough, submerged and rolled very quickly. Then they repeat it in the dark, total and absolute dark. Not even a charge LED on the buildings emergency exit signs.

hardly any

Don't know if a Chinook has any such automatics. In some ways I be surprised if they do, such automatics have a habit of not letting you "push the envelope" which an aircraft in a combat zone may wish to do... It's also added complexilty thus something else to go wrong.

Being RAF it won't be the first time they have dropped underslung loads and they'll know the aircraft very well and how much to reduce the pitch of the rotors for a given weight loss. I guess that they don't reduce the pitch until they feel the weight go rather than on a count, just in case the release doesnt happen...

Yes it does, and it needs them in case there is a load failure when the load is a heavy field gun etc.

Easy to allow that to be overridden when required.

Sure, but load failure is much more likely with a chinook.

The updated digital avionics that Chinooks have now have many features, apparently including auto-hover and automatic position control, with automatic movements in 30cm increments.

SteveW