Sleeve valve was commonly known in the Automotive-world , as "the Silent Knight" as the Patentee was Knight.
Among others, engines thus equipped, were used by Daimler, which were used for many years as the Royal car of choice. When Georgie -boy (edit: it was edward!) abdicasted and was exiled to France,with Wallis Simson, he took with him, one of the Royal Daimlers.
Rolls Royce have only been in that role, since the present Queen was crowned.
LOP operation , insight for beginners.
If your fuel-air mixture is too weak, it will not burn at all.
If it is too Rich, it will also not burn.
Engines that are equipped with manual mixture-controls, usually have them designed to operate over the rich-weak combustion range, additionally, they can continue weakening to the point of shutting off fuel flow completely......not many engines are operated at a significantly higher pressure than sea-level
Aero-engines spend most of their operating -cycle at altitude, this gives a lower air-density .
A cylinder-full of air at altitude, will have less oxygen in it than the same cylinder filled at ground level...(the air is packed in tighter, lower down! )
If you adjust for a good mixture on the ground, it will become richer as you ascend into thinner air.
Any surplus fuel, unburned in the cylinder, is wasted power. A rich exhaut is unused power.
A rich, combustible mixture can "explode" when ignited the ratio of air to fuel , where this happens, is readily established and well documented
Fortunately, for the person without a test-rig, laboratory or specialised monitoring facilities, there is a very useful side-effect of mixture-optimisation.
TEMPERATURE!
By monitoring cylinder-head temperature, it is possible to establish the optimum mix for cool running whilst getting the most energy-use out of the fuel.
It is not an ideal system, as it relies on the engine-operator having a true understanding of the combustion process and being able to monitor and control it accordingly.
A properly set-up electronic control -system can do this much better than a human. it's more accurate, faster and doesn't get distracted. unfortunately, when it goes T/U it's usually a total "nervous breakdown" We can compensate by having multiple redundancy. These things have to be certified, which takes time and a lot of cash from the manufacturer.
Pilots and engineers come ready-certified. With a short familiarisation-course, they're deemed fully-capable of managing a new (different) variation of engine.
Some pilots have a good mechanical understanding and awareness, they learn how to set the correct fuel-flow and manage their engine properly....the reward is mechanical reliability, reduced maintenance-costs and dramatically reduced fuel-bills.
Fuel is the cheapest thing in an aeroplane?- Really?
Think again...In an "average " SEP "spamcan," around half a litre is consumed per MINUTE.... save a teaspoonful per half-litre burned, multiply by the engine's service life.....still small-change?
Uk petrol pumps are calibrated according to strict legal standards. the dispense is allowed to be something like 0.5% under, or 1% over "strike"
In practical terms, a gallon can be a teaspoonful short, or two teaspoonsfull over and still be legal measure.
The major fuel companies employ pump-engineers solely to "tweak" the calibration down as close to the limit as they can!
For a teaspoonful?...yes! but any major will only operate a site that turns over ONE MILLION GALLONS PER YEAR....so how much is a million teaspoonsful?
Learning the hows and whyfors of running LOP, is a no-brainer for anyone who spends a fair time flying. The half-hour a week person is likely to have a higher maintenance bill than fuel-bill.
Someone flying every day, will have a cleaner, more reliable, longer-lasting engine.
Most Engineers are mechanics...they know how to put machinery back together properly, most know how to diagnose faults.
very few are able to actually operate the machine under real-service conditions. especially since the demise of the Flight Engineer!....but, was he a good spanner-man as well?
bit longwinded, but hopefully food for thought!
Last edited by cockney steve; 18th Apr 2014 at 20:52.
Reason: OOPS! it was Edward who toddled off with the Divorced yank.