Parrott langley research center summary an improved method for the design of expansion chamber mufflers is described and applied to the task of reducing exhaust noise generated by a helicopter. How twostroke expansion chambers work, and why you should care. An estimated exhaust belly gas temperature was 550c, which with hindsight was too hot. An improved method for design of expansion chamber mufflers with application to an operational helicopter by tony l. Each cad and any associated text, image or data is in no way sponsored by or affiliated with any company, organization or realworld item, product, or good it may purport to portray. Design of mufflers and silencers noise and vibration short course dept. How twostroke expansion chambers work, and why you should. For the past several years most of this info has been kept close to the vest. I bought an expansion chamber design program, and it produced numbers more in line with what i though i should have from what ive been reading. Multiple dual exhaust pipes were simulated using virtual 2stroke software to. Method 1 and method 2 two and three stage diffuser.
Therefore, free expansion must be allowed to occur, but expansion must ultimately be compensated for through system design. Design and analysis of a expansion chamber mufflers. The software uses mathematical formulas that are approximations of reality, and the software made for homecomputers uses even more simplified formulas because good simulation of expansion chambers requires much more. Building your own racing expansion chambers rdrz 350 ypvs. Two stroke engine expansion chamber design software. Expansion chamber design virtual 2stroke engine simulation. The expansion chamber design software micro car project. As you can see, modern twostroke expansion chambers create a complex scenario and are quite difficult to tune. What you need now is a chamber design that fits your specific tuned engine. Just a quick update on the progress of the freeware 2 stroke expansion chamber calculator software. Finally, enya came on board with very practical but heavy mufflers, usually held on with a very solid metal strap which abutted the exhaust flanges to eliminate stress on the crankcase sides.
Engineering 22 university of kentucky 18 2 6 2 where m is the expansion ratio chamber areapipe area 9 in this example and l is the length of the chamber. Look very good and i understand this program gave excellent performing pipes to others. I applaud you for taking on a project like a custom engineered expansion chamber. Engineering acousticssonic supercharging of 2 stroke. A diaphragm protected pressure switch shall be installed above the rupture disc for remote indication of a burst disc. The program takes your info and spits out a sheet with lengths and diameters. My professional 2 stroke expansion chamber design software is more sophisticated than other programs that only use a few basic formulas. It makes use of the energy left in the burnt exhaust exiting the cylinder to aid the filling of the cylinder for the next cycle. An expansion chamber was designed using the software on this site you could use the free mota expansion chamber software too, which is based on my software. This will get you started by providing, for your engine, the dimensions of an expansion chamber with a 2stage or 3stage diffuser. On a twostroke engine, an expansion chamber or tuned pipe is a tuned exhaust system used to enhance its power output by improving its volumetric efficiency.
Here you can see some examples of possible chamber designs. How to plot two stroke expansion chamber cones on paper from. Engineering acousticssonic supercharging of 2 stroke engines. Your speed demon muffler you advertising it for 34. How to build your own expansion chamber without any special tools. The software uses mathematical formulas that are approximations of reality, and the. An improved method for design of expansionchamber mufflers with application to an operational helicopter by tony l. How to design a two stroke expansion chamber performance. Jan 23, 2019 2 stroke exhaust expansion chamber calculator using 3 methods. Jan 28, 2011 i bought an expansion chamber design program, and it produced numbers more in line with what i though i should have from what ive been reading. My expansion chamber calculator, how to obtain and use it the mathematical basis for the calculations of the return waves in my excel file an example of pipe analysis and redesign pipes built using this method my video showing how to make a pipe by hand how eccalc agrees with the real life exhaust pressure graphs from blair four examples showing how accurate eccalc is compared to.
Today i am revealing most of the tricks of the trade the bill of materials for building these pipes is as follows. Pipe design is very interesting and was a heck of a lot more involved than i had first thought. Trackmania power up expansion pack is a fun game that allows you to design and race on custom 3d tracks. Free expansion chamber design utility download expansion. We also have a simple 2stroke expansion chamber design program. Expansion chamber software free download expansion chamber. Parrott langley research center summary an improved method for the design of expansionchamber mufflers is described and applied to the task of reducing exhaust noise generated by a helicopter. Expansion is provided by the movement of a tough, elastic diaphragm enclosed in a protective steel chamber. Performance speeddemon muffler with expansion chamber. Thermal expansion will occur between all fixed points in the piping system.
It is a freeware 2 stroke expansion chamber exhaust calculator program. Expansion chamber exhaust design software i have just bought and installed this 2 stroke wizard tuned pipe expansion chamber design software package. Primary action the main action of an expansion chamber is the creation of reverse waves returning to the cylinder that happen from the main pressure wave in it expanding and then contracting at the diffuser and baffle cones. Free 2 stroke expansion chamber calculator software update. An expansion chamber is a twostroke engine device which uses shapes and sizes of exhaust plumbing designed to specifically address the problem of fresh charge escaping the combustion chamber prior to the exhaust valve closing, thus being wasted. Expansion chamber, free expansion chamber software downloads. This software covers the 3 stage diffuser type expansion chamber exhaust as per equations provided in his book entitled design and simulation of twostroke engines published in 1996. The most common method is the inclusion of expansion elbows, loops, or zbends. Keep in mind that the power graph is only power that. File type pdf two stroke engine expansion chamber design software two stroke engine expansion chamber design software unlocking the secrets of 2 stroke expansion chamber exhausts e1 this is the first video in a series looking at the science and mysteries of 2 stroke expansion chamber exhausts. To edit a copy of this document, go to file at the top left of the page, and either download a copy. I used my expansion chamber software to see what the difference in power and powerband would be if there was a controllable position internal baffle cone.
What are you guys using for expansion chamber design ktog. Of course the dimensions so provided could be inserted in a mota engine data file and motax then used to provide an optimum expansion chamber design for your engine over your choice of speed. On machines with liptype seals it reduces pressure buildup which can cause seal failure. This pack includes new play modes, new construction blocks, video editing options, bug fixes and much more. Performance fabrications is dedicated to manufacturing the finest bespoke hand crafted exhaust systems available.
Two stroke tuning by alexander graham bell excellent book. Expansion chamber design an expansion chamber was designed using the software on this site you could use the free mota expansion chamber software too, which is based on my software. The first part of your post notwithstanding, your question does merit a response. The placement and shape of the forward cone generates vaccuum to help drag out the old, spent charge and help pull the fresh charge up from the cases while the transfer and exhaust ports are all open scavenging. Calculator mention in video sent to me by nico as called cone layout. Any donations greatly appreciated, please use paypal link. Hes done a lot with pipes and still sells cone sets i think. That is because the pressure wave created when the exhaust suddenly enters the exhaust pipe travels at a certain speed, so many meters per second. May 03, 2018 how to design a two stroke expansion chamber performance exhaust step 2. Computer software can help you with the design, but dont expect super design from the software. I thought about replacing the one on my bike because it had a medium sized dent and i thought that was hurting it alot when i read how an expansion chamber works.
On machines with liptype seals it reduces pressure buildup. One last thing regarding design, computer software can help you with the design, but dont expect superdesign from the software. The gits expansion chamber absorbs surges and expansion of gas or fluids in a closed system. Exhaust pipe design with cone layout software by paul crowe if you have ever tried to layout a conic section on sheet metal, cutting just the right piece, that when rolled over and joined on edge, you have a cone with the exact shape, size and angled openings desired, you know its not easy. The wave is first created when the exhaust blasts into the exhaust port. Direct comparison between different types of exhausts for the twostroke engine, on the left you can see the engine and its exhaust, in the. This program calculates the dimensions for both double and triple stage diffuser expansion. Our performance speeddemon muffler with expansion chamber is specifically designed for 2 stroke engine kits. Free download here this program calculates the dimensions for both double and triple stage diffuser expansion chambers from a few basic engine dimensions.
From reference 1, we know that wave speed in the pipe is effectively independent of engine rpm and largely dependent on temperature of the gases in the pipe. But, you may not dependence to influence or bring the baby book print wherever you go. Those used in this program have been chosen for petrol engines, and are in the range 50cc up to about 500cc per cylinder. Freeware 2 stroke expansion chamber exhaust calculator program. The computeraided design cad files and all associated content posted to this website are created, uploaded, managed and owned by third party users. The information used in the programs calculations was taken from the books the basic design of the two stroke engine and design and. It is the twostroke equivalent of the tuned pipes or headers used on fourstroke cycle engines. Nov 02, 2019 this pipe consists of an expansion chamber which serves to create both the returning rarefaction and pressure waves. You can open the books wherever you desire even you are in the bus, office, home, and further places. Expansion chamber calculations by an excel workbook file expansion chamber design professor blairs tests proved that the return waves timing can be calculated fairly closely using the straight distances and the pressure wave speed in the pipe for that distance. Expansion chamber calculations by an excel workbook file. Oct 01, 2010 for the past several years most of this info has been kept close to the vest.
Jul 25, 2007 exhaust pipe design with cone layout software by paul crowe if you have ever tried to layout a conic section on sheet metal, cutting just the right piece, that when rolled over and joined on edge, you have a cone with the exact shape, size and angled openings desired, you know its not easy. To learn more about how expansion chamber exhaust systems work, read this great primer. But at what part of the powerband it does it is dependent on how far from the engine the diffuser cone and baffle cone are. How to design a two stroke expansion chamber performance exhaust step 2. Free expansion chamber design utility download software at updatestar 1,746,000 recognized programs 5,228,000 known versions software news. This pipe consists of an expansion chamber which serves to create both the returning rarefaction and pressure waves. New version of 2t exhaust calculator it is a freeware 2 stroke expansion chamber exhaust calculator program download at.
Multiple dual exhaust pipes were simulated using virtual 2stroke software to find the optimal single. This expansion chamber is not the product of simple correlations as for other products that abound on the web, but an automatic design created by mota which. There are several coefficients used in the design of the expansion chamber a these are a function of the engineas state of tune. Oct 25, 2016 expansion chamber design virtual 2stroke engine simulation. I had a later version on my 1968 taipan 19 which was very effective. How twostroke expansion chambers work and why you should care. The expansion chamber design software is used to design the tuned pipe for the exhaust system of the micro car engine. An expansion chamber is an exhaust system used on a twostroke cycle engine to enhance its poweroutput by improving its volumetric efficiency. Design and analysis of a expansion chamber mufflers chandrashekhar bhat, s.
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