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have you ever seen or heard about this puppy??
saw it for the first time tonight and it took me a while to figure out what the fuck i was looking at
http://www.ptfnasty.com/images/jpg/deltic/Deltic%2018.jpg
http://i7.photobucket.com/albums/y295/renegadeofpunk03/Picture1.jpg
Napier Deltic...
Jeroentjuh
10-06-2007, 11:34
http://upload.wikimedia.org/wikipedia/commons/6/60/Napier_deltic_animation.gif
An animated schematic of a Deltic engine. The inlet is coloured green and the outlet purple. Notice the bottom shaft contra-rotating with respect to the other two; the lag between the exhaust and inlet ports opening; and that ignition occurs when the pistons are not at equal positions in the cylinder.
http://upload.wikimedia.org/wikipedia/en/thumb/2/2a/Napier_Deltic_Engine.jpg/800px-Napier_Deltic_Engine.jpg
The Deltic story began in 1943 when the British Admiralty instigated a committee to develop a high-power, lightweight diesel engine for Motor Torpedo Boat[1]. Hitherto in the Royal Navy, such boats had been driven by petrol engines but this fuel is highly flammable, making them vulnerable to fire, and at a disadvantage compared to the German diesel powered E-boats.
Until this time diesel engines had poor power-to-weight ratio and low speed. Before the war Napier had been working on aviation diesel designs (licensed versions of the Junkers Jumo 204) and the Admiralty felt these would be a reasonable starting point for the larger design they required.
The original Napier Culverin was an opposed piston design. Instead of each cylinder having a single piston and being closed at one end with a cylinder head, the elongated cylinder contained two pistons moving in opposite directions toward the centre. This negates the need for a heavy cylinder head This led to a rather "flat" engine, intended to be buried in the wings of large aircraft. The Admiralty required a much more powerful engine, so for the added power Napier took three of their original Culverins and "bolted them together".
The result was an inverted triangle, the cylinder banks forming the sides, and tipped by three crankshafts, one at each corner of the triangle. The crankshafts were connected with phasing gears to drive one output shaft. Various models of Deltic engine could be produced with varying numbers of such three-cylinder banks, though nine and eighteen cylinders were the most common, having three and six banks respectively. In 1946, the Admiralty placed a contract with the English Electric Company, parent of Napier, to develop this engine[1].
One of the interesting features of this engine was the clever way the crankshaft phasing was arranged to allow for exhaust port lead and inlet port lag. These engines are called 'uniflow' designs because the flow of gas into and out of the cylinder is one way, assisted by mild supercharging to improve cylinder exhaust scavenge.
Napier Deltic engine at the National Railway Museum, York, UKEarlier attempts at designing such an engine failed because of the difficulty in arranging the pistons to move in the correct manner, for all three cylinders in one delta. Napier solved this problem by gearing the crankshafts so that one of them rotated in the opposite direction to the other two.
In an opposed piston design with no inlet or exhaust valves, and no ability to vary the port positions, the deltic design arranged each crankshaft to connect two adjacent pistons operating in different cylinders in the same plane, using forked connecting rods, one an 'inlet' piston used to open and close the inlet port, and the other an 'exhaust' piston in the adjacent cylinder to open and close the exhaust port.
Crankshaft connecting rod journals were arranged so that the exhaust piston 'led' the inlet piston by 20 degrees of crankshaft rotation. This meant that in any one cylinder, the exhaust piston reached its top-dead-centre position before the inlet piston in the same cylinder, and that the exhaust piston was on its way down the cylinder before the inlet piston reached its top-dead-centre position.
This arrangement allowed the exhaust port to be opened well before the inlet port, and allowed the inlet port to be closed after the exhaust port, which led both to good scavenging of exhaust gas, and good volumetric efficiency for the fresh air charge. The arrangement suffered from the disadvantage that the two pistons contributed unequally to power output.
Development began in 1947 and the first Deltic unit was produced in 1950. By January 1952 six engines were available, enough for full development and endurance trials. An ex-German E-Boat, powered by three Mercedes-Benz diesel engines, was selected for these trials, since its power units were of approximately equal power to the new 18 cylinder Deltic engines. Two of the three Mercedes-Benz engines were replaced with Napier Deltics, the compactness of the Deltic being graphically illustrated: they were half the size of the original engines. The Deltic weighed one fifth of that of its contemporaries of equivalent power[1].
Proving successful, the Deltic diesel engine became a common powerplant in small fast naval craft. The Royal Navy used them first in the Dark-class fast attack craft. Subsequently they were used in a number of other smaller attack craft. The low magnetic signature lent itself to use in mine countermeasure vessels and the Deltic was selected to power the Ton-class minesweeper. The Deltic engine is still in service in the Hunt-class. These versions are de-rated to lower the stress on the engine.
The Deltic-powered Hunt class Mine Countermeasure Vessel HMS LedburyDeltic diesels served in MTBs and PT Boats built for other navies. Particularly notable Was the Norwegian Tjeld or Nasty class, which were also sold to Germany, Greece, and the United States Navy. Nasty-class boats served in the Vietnam War, largely for covert operations.
While the Deltic engine was successful and very powerful for its size and weight, it was a high-strung unit, requiring much maintenance. This led to a policy of maintenance by unit replacement rather than repair in place. Deltic engines were easily removed upon break down, generally being sent back to the manufacturer for repair.
A turbo-compound variant of the Deltic was planned[1]. This would have inserted the turbine stage from a Rolls-Royce Nene turbojet into the centre of the delta. The engine acted as the gas generator, driving the turbine with the exhaust gasses, recycling some energy that would otherwise have been lost. Such an engine was hoped to produce 6,000 horse power....
did you know some of that? or was it just google? nice info none the less...
Next....
http://airpower.callihan.cc/images/Engines/04-Rhineback-Gnome%20Rotary%20Engine.JPG
The rotary engine was an early type of internal combustion aircraft engine, used mostly in the years shortly before and during World War I. It was also used in a few motorcycles and cars.
The Gnôme (and its copies) had a number of features that made it unique, even among the rotaries. Notably, the fuel was mixed and sprayed into the center of the engine through a hollow crankshaft, and then into the cylinders through the piston itself, a single valve on the top of the piston let the mixture in when opened. The valves were counter balanced so that only a small force was needed to open them, and releasing the force closed the valve without any springs. The center of the engine is normally where the oil would be, and the fuel would wash it away. To fix this, the oil was mixed in liberal quantities with the fuel, and the engine spewed smoke due to burning oil. Castor oil was the lubricant of choice, its gum-forming tendency being irrelevant in a total-loss lubrication system. An unfortunate side-effect was that World War I pilots inhaled and swallowed a considerable amount of the oil during flight, leading to persistent diarrhoea. Finally, the Gnôme had no throttle or carburetor. Since the fuel was being sprayed into the spinning engine, the motion alone was enough to mix the fuel fairly well. Of course with no throttle, the engine was either on or off, so something as simple as reducing power for landing required the pilot to cut the ignition. "Blipping" the engine on and off gave the characteristic sputtering sound as though the engine was nearly stalling, though it did not stall as quickly as conventional engines due to its great rotational inertia.
Throughout the early period of the war, the power-to-weight ratio of the rotaries remained ahead of that of their competition. They were used almost universally in fighter aircraft, while traditional water cooled designs were used on larger aircraft. The engines had a number of disadvantages, notably very poor fuel consumption, partially because the engine was always "full throttle", and also because the valve timing was often less than ideal. The rotating mass of the engine made it, in effect, a large gyroscope. This could result in tricky handling. The Sopwith Camel, for example, was known to turn very nimbly to the right, but rather sluggishly to the left. Nevertheless, rotaries maintained their edge through a series of small upgrades, and many newer designs continued to use them.
http://www.keveney.com/img/gnome.gif
Engine weights no more then 68 kilo, approx 800hp :eek:
http://www.angellabsllc.com/index.html
http://www.angellabsllc.com/images/Engine_Comparison.jpg
http://www.angellabsllc.com/images/P5170664-5.jpg
http://www.angellabsllc.com/images/P5170664-6.jpg
@Stijn:
There are engines which look like the one you posted, but then the cilinders stay in place and the crankshaft makes ex(can't come up with the word) circles.
I know, those are the later 'star' engines which were far more practical. As you can read the early 'rotary' engines had some very weird charactaristics like: no throttle, one valve in piston one in the head, runs on fuel/oil mixture.
Yes, very interesting to see these older 'rotary' and other type engines... You must be very creative to come up with these engines...
@stijn: sober yet?
Interesting idea.
http://www.greencarcongress.co....html (http://www.greencarcongress.com/2007/06/nevis_engine_co.html)
The NEVIS (New Exhaust Valve & Intake System) engine embodies a new two-stroke combustion cycle (the “Bortone” cycle after its inventor) and a new design than combines, among other features, annular (i.e., doughnut-shaped) pistons, modular cylinder construction and a sinusoidal camshaft similar to those adopted in engines with cylinders arranged co-axially around the shaft.
The company claims that the engine offers efficient combustion at all levels of power demands, and that it can nearly double the fuel efficiency obtained by conventional internal combustion engine technologies.
Although the NEVIS engine is lighter and smaller than a conventional ICE engine of comparable cylinder displacement, it offers more power, due in part, the company says, to the engine offering six times the number of power strokes per revolution than a traditional four-stroke engine.
http://i9.tinypic.com/52bho29.jpg
Those rotary engines are very cool to see at work. Have seen it at a air show once, pretty weird :)
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