10 most important / noteworthy UK steam designs .your views and why

...... or both!

It's worth noting that, unlike Leader, the Paget loco's cylinders were single acting.

 

... and aero engines (There were nearly 70,000 Bristol Perseus / Hercules / Centaurus aero engines built - don't know how those numbers compare with cars, but hardly insignificant)

Indeed.

Again - possibly true for motor car engines, but clearly not true for aero engines.

Tom

 

Well, I have been told, independently by two people, that sleeve valved aero engines needed to be warmed up ultra carefully, failing which there was a real risk of serious mechanical failure with the lubricating oils of the time. This accords exactly with what my own grandfather told me about sleeve valved Daimler cars. Rolls-Royce, and Hispano Suiza of course never used sleeve valves for any of their power units. Bulleid either asked the wrong people or didn't listen to what he was told.

PH

 

Rolls Royce made the sleeve valve Eagle, as a competitor to the Napier Sabre.
The aero engines used the Burt-McCollum single sleeve valve as opposed to the twin sleeve valves of the Daimler knight engines. Neither of which are the same as Leaders as I understand it, although the aero engine practice clearly influenced the leader implementation, but steam engines and internal combustion engines are both very different beasts.
Leaders valve gear appears to have been a case of Bulleid taking piston valves and placing them around the cylinders rather than beside them as in a more conventional locomotive. Although I haven't seen drawings for them, so I may well be far off the mark.

 

Not so far off ..... As if the sleeves themselves weren't novel enough, OVB added a oscillating motion to the valves. This coupled with the reciprocating longtitudinal motion imparted a 'figure of eight' movement to the sleeves. The intention was to improve lubrication, though in practice the lugs extending from the (outer) end of the sleeves had a nasty habit of fracturing. Following several failures under test, the oscillating motion was disconnected.

The first live steam test of the sleeve concept (ahead of Leader itself) was conducted on Marsh Atlantic 'Hartland Point' without any sealing rings between sleeve and bore, as Bulleid initially thought that the contact area alone would provide sufficient resistance to escaping steam. Somewhat unsurprisingly, it didn't, much to the chagrin (and no doubt embarrassment) of Bulleid and the mirth of brother-in-law Ivatt, who was on site to witness the test!

Here's an old film clip from YouTube (after some stills) of Leader's bogie on test. **Warning** It's hypnotic!