Shipboard Helicopter Landing Aid

[Jemiba]

In „Der Flieger“, April 1961 the German patent 92b 1086583 is shown, filed by J. Böckelmann, La Spezia/Italy. It deals with a
device to ease landing of a helicopter on a ships platform, especially during rough seas. A cone is lowered on a cable down to
a kind of a cage set into the landing platform, then the heli is pulled down by a winch.
Isn’t that the Beartrap sytem deployed by the Candian Navy ?

 

[Bill Walker]

This is similar to the Bear Trap, but differs in several details. I suspect if you dig deeper the patent doesn't cover the idea of winching down the helicopter, but details in the sequence of attaching the cable, winch control, etc.

From memory, Bear Trap drops a signal cable from the helicopter, which then pulls up the heavy cable from the ship. Most of the engineering clevernous (and therefore the patentability) of Bear Trap lies in the winch control.

 

[Jemiba]

Thanks for this explanation ! In the short article there's no mention of a signal cable, but that
the landing cable would be dropped onto the deck. As it would be fitted with the mentioned cone,
this procedure could result in damages to the ship in heavy seas, I think.

 

[Bill Walker]

It also results in a heavier installed weight being dragged around all day by the helicopter. But it might get around any Bear Trap patents.

A patent attorney I used to work with always said "necessity is the mother of invention, but infringement is the father."

 

[riggerrob]

Bill Walker understands the basics of the Royal Canadian Navy’s Beartrap helicopter haul-down system.
I have worked with bear trap on the flight decks of HMCS Athabaskan and HMCS Iroquois.

Our Sikorsky Sea King helicopters had two extra landing gear legs: main probe and tail probe. The main probe was at the centre of gravity and included an extendable cylinder with a wide collar at the bottom. The light-weight messenger cable slid through the centre of the hollow main probe. A steel tube cage and winch protruded into the main cabin.
A second probe, near the tail wheel prevented the helicopter from yawing once on the deck. The trial probe expands fingers to catch the T-rails of the tail grid ... similar to the British Harpoon and Russian navy systems.

Beartrap ships’ fittings include the bear trap, a series of wiches, a series of rails and the tail locking gird. The bear trap is a shallow cart with two jaws that garb the main probe. A hole in the middle of the bear trap accommodated cables and allowed them to connect the winches below deck. The tail locking grid is a series of t-rails oriented fore and aft. All these at controlled by a landing officer in the Howrah, a glasses in booth semi-submerged in the forward, starboard corner of the flight deck.

The Beartrap system was developed by Dominion Aluminum Forgings during the late 1950s and early 1960s to allow helicopters to land on the wildly pitching decks of destroyer escorts. This allowed convoy-escorting frigates and destroyers to extend their search area with helicopters. The Beartrap system was sold to India and Italy and the US Navy adopted the up-dated LAMPS III system during the 1980s.