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It took me a little while to work out why the slot is at a funny angle to the arm. It is quite a subtle piece of geometry. It appears to be designed so that the cylinder can be 'linked-up' running ahead, but the adjustment has very little effect on the timing when running astern.If the slot were at right angles to the arm radius, as one might at first expect, then any adjustment for running ahead would result in over-travel of the expansion link when moved across to the astern position. Or someone would have to frantically un-twiddle the knobs before yanking the reversing handle.
That piloted reversing system in action looks spectacular Chris....'so little effort to achieve the movement of such mass' A credit to the original designers ......[over linkages & fulcrums & linkages]Question.......have viewed all of the postings, but unsure if I have missed.....'can the engine be reversed without coming to zero revolutions?' Derek
In the video that Michael posted they did exactly that, though I would think that doing so at high speeds would put an awful lot of strain on the parts, the mass of the prop as well as the engine is a lot!
Quote from: crueby on May 23, 2023, 03:51:22 AMIn the video that Michael posted they did exactly that, though I would think that doing so at high speeds would put an awful lot of strain on the parts, the mass of the prop as well as the engine is a lot! I thing if the timing is correct and perhaps with a bit of luck an instant reversal can be done without damage. It would get one's attention, however, since the prop would be rotating against the vessel motion. Lots of noise and vibration at the least.The primary problem is likely the introduction of high pressures in the low-pressure parts of the engine, such as the intermediate receivers and pistons.The Handbook for the Care and Operation of Naval Machinery says,"Reversing. When reversing, the throttle should first be closed ,and engine then reversed ; but when the emergency signal is received(that is, a signal to back full speed when going ahead) , the engineshould be immediately reversed , even at a risk of breaking something.This signal should never be given from deck unless it is an emergencysignal."https://books.google.com/books?id=6rQ3AAAAMAAJ&dq=Handbook+for+the+Care+and+Operation+of+Naval+Machinery&printsec=frontcover&source=bl&ots=CvVxydp74M&sig=jAoSe_dxumddbp0Um-emhG6gjPw&hl=en&sa=X&oi=book_result&ct=result#v=onepage&q=Handbook%20for%20the%20Care%20and%20Operation%20of%20Naval%20Machinery&f=falseGene