Here is another pic of the same Saito .72 when running. I looked up the website where this came from, and it isn't valid now. The member hasn't logged on to RCU in more than 3 years. Here is the defunct address: http://www.geocities.com/ramair1968/PULSE_JETS.html. From what I remember, his boss gave him time to work on this. He had some good comments on developing it.

The YS system is the most practical for model aircraft. It works and adds little weight.

[8D]

[youtube]http://www.youtube.com/watch?v=ms3WpU7KSn4[/youtube]

The YS has my vote, there is no other 4C engine and most 2C of the same size that will run with them. Here is a YS 1.10 beating a Piped Ducted Fan .91.

Just Watch these video's and drool!

http://www.youtube.com/watch?v=dburR...layer_embedded

http://www.youtube.com/watch?v=DzvkD...eature=related

http://www.youtube.com/watch?v=S_iXV...eature=related

I don´t know why that video makes me want one of those!!!

I really don´t know! do you?

The thread is about Glow Engines that are "Super Charged". The Video just demonstrates there throttle responce and gut wrenching performance.

Tom,

Do you have a video of it running?

Ok, that first one there made me really want to buy a Dago Red or something similar to carry my YS 110 which needs a new plane.

What prop are they using to get such high speed?

I think the APC 13-13 is one of there favorites.

YS engines use a positive displacement pump, the bottom of the piston compresses the intake charge. Look up Bourke Engine on Wikipedia:

[link]http://en.wikipedia.org/wiki/Bourke_engine[/link]

YS engines are not for everyone. They are top-of-the-line High Performance engines, however they are very in-tollerant to abuse normally associated "novice" pilots. The most common "mistake" novices make with a YS engine is their lack of preparation to accomodate the engine in the airplane. In other words, the fuel tank can't hold the needed pressure, there's rarely the greatly needed fuel filters, and rarely have the proper lines for pressure release and pressure line accomodation.

Another mistake "novices" make is, they have no idea how to tune the engine properly, and more often than not... the engine is UNDER-PROPED for the type of airplane. This becomes a major annoyance for the owner. 90% of the YS engines I've worked on for "novices" were total disasters. The engines were grossly mis-tuned, under-proped, and rarely had fuel filters. You can get away with this kind of stuff with Saito, OS, and other four strokes, but NOT YS engines.

YS engines also REQUIRE some routine maintenance! The valves must be kept in adjustment.and the gaskets and o-rings need to be inspected along with checking the oneway valve. The fuel tank needs to be checked for leaks as well as the lines and fittings.

While YS engines are fully capable of running at the extreme topend of the RPM spectrum, this is not a good practice. The published range for the 1.10 FZ is 2000-13,000 RPM. If you consistantly run it at 13,000 RPM, you are headed for trouble! The piston ring will wear out much faster than normal and the engine won't idle smoothly until the ring is replaced. Another mistake people make with YS is they tend to over-tighten the screws thinking there's a leak when the engine doesn't run right. Over tightened screws cause more leaks than loose screws do.

In conclusion, if you are not willing to set-up your airplane to properly accomodate the YS and perform routine maintenance along with other chores associated with it, I would HIGHLY RECOMMEND you go with a different engine like Saito or OS.


YS Technology at its FINEST

YS four strokes are founded on (YS developed) crankcase super charging and fuel injection technology. I'll attempt to explain how all of this works in plain english...

All four stroke engines rotate two full revolutions to make up the four strokes. IE: INTAKE stroke= 180 degrees, then the COMPRESSION stroke=180 degrees, the POWER stroke=180 degrees, and finally the EXHAUST stroke=180 degrees, hence TWO revolutions of the crankshaft. This means that the piston travels up twice, and down twice to complete the four cycles of which only 25% (power stroke) of the cycles produce power. The remaining 75% consumes power. Also in a conventional four stroke, all the work is performed on the TOP SIDE of the piston. In YS engines, both the top and bottom of the piston have a job to do. YS technology utilizes 2/3rds of the 75% of the power robbing cycles to boost the intake cycle (IE:super charge). This is done by taking advantage of the bottom side of the piston's up & down motion. On the up strokes, the piston draws in air into the crankcase, however not the fuel! On the down strokes of the piston, it "pushes" the charge through the second half of the carb where it is injected with fuel then pressurized into the airchamber. The YS engine gets TWO charges of pressure into the airchamber before the intake valve opens up. The timing of the inlet to the crankcase and the outlet to the airchamber is controlled by a rotary valve on the back of the crankshaft. While all of this crankcase charging is being pushed into the airchamber, there's a small hole in the front section of the crankshaft that is timed to send a pressure signal to the fuel regulator. This signal opens the plunger and injects fuel in the second half of the carb (the half that goes to the airchamber). This pressure signal also provides the needed fuel tank pressure through the one-way valve. Fuel injection is a necessity, as there is lots of air pressure on the airchamber side of the carb! Here is what all this means; Instead of having the piston on intake stroke "suck" the mixture into the cylinder like a conventional four stroke, it's now "pushed"or super charged into the cylinder by the airchamber. This takes a lot less energy which translates to more of the horsepower going to the propeller (in simple terms). Also, the cylinder is "packed" with more air/fuel mixture increasing the "effective" compression. Once again, consuming less power and actually generating more horsepower.

Now let's take this a step further... In a conventional four stroke, as the piston moves up & down it creates both a vacuum (going up) and pressure (going down) in the crankcase. This consumes horsepower by passing air back & forth through the crankcase vent. On a YS engine, the "wouldbe" vacuum portion of the piston stroke is "equalized" via: the first half of the carb (inlet) . IE" less power consumed. The "wouldbe"pressure portion of the piston stroke is "equalized" via: the second half of the carb going to the airchamber. Both of these functions are synchronized and managed by the rotary valve. Hence, once again more power available to the prop. This is why it's so critical that all YS four strokes be completly sealed. Meaning absolutely no leaks, period! The entire function depends on the balance of perssures generated in the crankcase. Not only does this balance provide the super charge to the cylinder, but it also times the fuel injection and pressurize the fuel tank as well. For all of this action to function as designed it's important the the YS engine be in perfect mechanical condition!

This is an over-simplistic explaination, however it gives you an idea of the extreme engineering and mechanical functions that YS designed into their four strokes. There's no doubt that you get the most "bang for the buck" with YS engines when you consider the engineering, machining, and technology invested in every engine.

Another tid-bit of information:
All other four strokes use "blow-by" for lubrication in the engine. "Blow-by" is nothing more than your piston ring leaking, thus blowing expended gasses and oil into the crankcase then eventually venting it out. In a YS engine, "blow-by" is totally unacceptable. In fact "blow-by" will throw your YS engine so far out of tune that it won't hardly run especially at low RPM. The reason is, the crankcase pressure manages the entire engine, if the pressure changes then so does the tune. So "blow-by" is not goood. Since YS doesn't use "blow-by" for lubrication, then how does it get oiled? It's a very elegant and well designed system! Here's how it works...

When your engine is running, fresh air is brought through the first butterfly in the carb and sent directly into the crankcase. When the crankcase gets pressurized and the rotary valve opens, the charge is sent through the second butterfly in the carb. As the air passes through here, it gets charged with glow fuel and pressurized into the airchamber. The intake runner has four holes around the intake valve stem support.

The pressurized air/fuel mix gets pushed through these holes and makes its way inside the valvecover and pressurizes this area with air & fuel. This lubricates the valves & rockers. But that's not all, the air/fuel pressure passes down through the pushrod guides and lubricates the tappets (lifters) and continues down to the camshaft, thus lubricating the crankshaft bearings and finally intrudes the crankcase where it lubricates the rod, and piston. The excess air/fuel then passes through the carb, and airchamber and finally maskes its way to the cylinder and gets used and exhausted. This is a very elaborate oiling system that works great, and it sure beats the hell out of "blow-by"!

Four strokes obviously benefit from superchargers. About two stroke superchargers: While a supercharger won't provide a performance boost on a two stroke by itself for reasons mentioned above concerning exhaust timing, it does allow the use of a much larger carburetor which in and of itself improves performance. Bottom line: yes, with a bigger carb they improve performance but this a totally different reason why they work on four strokes. I'd get into it deeper but dinner is ready!

Max

Any vids of that drag car running? that looks cool...

Yes, several. Go to the actual Youtube video, and click on the users name and the other vids will come up in a list.

hey my name is casey i was wondering where the hell did ya get that electric charger i want to buy one so email me at [email protected] with the info on where to buy one thank you very much dude

hey man do you know where kmot got that that blue electric supercharger and where i could find one let me know

The Superchargers are available from

http://www.rbinnovations.com/

or from Tower Hobbies

http://www3.towerhobbies.com/cgi-bin...&search=Go

First off, the blue electric supercharger is not an RB Innovations product. Those are not electric, they are belt driven off the engine.

The electric supercharger was produced by a company in Arizona called "MPPA". I forget what those initials stood for. Something like "M........ Performance Products A............"

Anyway, they went out of business years ago.

Edgar T Westbury wrote this:

Crankcase compression
The limitation in volumetric effeciency of two-stroke engines is primarily due to the incomplete charging of the cylinder by using the crankcase as a pump. Apart from the loss of effective volume through imperfect port timing, the necessary clearance space to accommodate working parts imposes a limit on the pressure which can be produced in the crankcase. Many designers have taken staps, sometimes drastic, to reduce crankcase clearance to the bare minimum in order to improve both suction and pressure effects.
While these measures are often beneficial, they may in some cases defeat their own purpose by increasing the load involved in charging. The function of the crankcase is not so much that of a pressure pump as a displacer, and work done in producing pressure is a dead loss from the aspect of mechanical efficiency, which is one of the virtues of the simple two-stroke. Unfortunately, a certain amount of pressure is necessary to charge the cylinder in the very brief period allowed for transfer port timing, in a high speed engine; but, again, too high a transfer pressure may cause turbulence in the port and impair scavenging.

Attempts have often been made to improve the volumetric efficiency of two-stoke engines by using an oversize charging pump of some kind. This may take the form of a separate charging cylinder, as in the original engine by Dugold Clerk, or a rotary blower. Alternatively, crankcase displacement can be increased by adding a crank or or eccentric driven displacer piston, or using a stepped main piston. This was done in the Dunelt motor-cycle, which had a certain vogue in the 1920's, but did not prove the advantages of the method. Such engines have sometimes beeen described as "supercharged" but this term is more correctly applied to engines in which the cylinder is charged at more than atmospheric pressure.

This is clearly impossible in normal two-strokes in which exhaust and ports are open simultaneously. They can, however, be "super-scavenged" by an oversize charging pump, often with some advantage, but at the expense of economy, because wastage of fuel through the exhaust port is inevitably increased. This may be tolerated in racing engines, and is no disadvantage in diesel engines of the injection type, which are charged with air only. In my experiments, however, I have failed to obtain any substantial increase of performance in two-strokes by increasing the charging pump volume.

It is a waste of money to buy the "supercharger" and it is a business for the maker who are producing the "supercharger" who are not giving the effect of the two stroke engine cause all ports are still open.

Edit: missed some text..