Hiceadha Posted October 16, 2013 Share Posted October 16, 2013 Hi I'm new here and am about to start an engineering project for university where I' designing a small ultralight engine. I thought where is this more relevant then to flying. I have an interest in paramotors and would love to build one given the time and facilities hopefully in the near future. As for the engine I was hoping to get some tips on what is already available in the market and whats wanted. If I link the design to paramotors then it will be a better project overall so given the chance to get any type of engine for your own diy project what would you want, 2-stroke, electric etc.? to give me an idea of whats wanted. Thanks Quote Link to comment Share on other sites More sharing options...
Guest Posted October 16, 2013 Share Posted October 16, 2013 Welcome to the Paramotor Club. There are many engines for us to select from. But to answer the 'what do we want' from an engine question.... the answer is simple Focus your efforts on (Power / thrust output to Weight) SW Quote Link to comment Share on other sites More sharing options...
s1buell_wl Posted October 16, 2013 Share Posted October 16, 2013 Few off the top for me • Horse power to weight ratio (how much HP can you give me in the lightest package) • Zero vibration • Low heat and motor with good heat dissipation • Quite • Good acceleration (Rapid RPM increase) • Easy start • 0 effect due to altitude • Fuel efficient Battery would be the best but current cell technology limits are slowing the development of a practical solution 2 stroke has been done to death (not sure what you can improve) 4 stroke is being tried but the problem becomes weight. Quote Link to comment Share on other sites More sharing options...
gordon_dunn Posted October 16, 2013 Share Posted October 16, 2013 One of the most successful paramotor engines ever produced is the Top80, compact lightweight, good power weight ratio, etc... relatively cheap, easily serviced, etc.... 2 Strokes have many advantages over 4 stroke- in terms of simplicity, but the price to pay is fuel economy. Would be interesting to do a project to try and combine the benefits of 2 stroke with increased economy- replacing the carb and tuned pipe system with direct fuel injection- electronically controlling fuel metering and spark timing..... GD Quote Link to comment Share on other sites More sharing options...
Guest Posted October 16, 2013 Share Posted October 16, 2013 Now a direct injection 2 stroke.. Thats what I am talking about! SW Quote Link to comment Share on other sites More sharing options...
speedmouse Posted October 16, 2013 Share Posted October 16, 2013 Injection on a 2 stroker . What would the benifits be and what about the negatives. Im not that good with engines but id be interested to know more about what could be acheived. Quote Link to comment Share on other sites More sharing options...
speedmouse Posted October 16, 2013 Share Posted October 16, 2013 http://www.ecotrons.com/ParaMotor_Engin ... n_kit.html Two stroke injection for you simon Quote Link to comment Share on other sites More sharing options...
gordon_dunn Posted October 16, 2013 Share Posted October 16, 2013 Injection on a 2 stroker . What would the benifits be and what about the negatives. Im not that good with engines but id be interested to know more about what could be acheived. Basically with a 2 stroke direct injection you'd have a small lightweight compact engine that can be used in any orientation, a greater power to weight ratio than equivalent 4 stroke, and matching fuel economy of a 4 stroke.... On current 2 strokes with a tuned pipe system, upto 25% will pass straight through the engine/exhaust system unburnt when at full operating rpm. The extent of unburnt fuel varies depending on the engine setup and rpm... but generally it is accepted in 2 strokes. With an accurate metering system and direct injection, this would eliminate excess fuel entering the combustion chamber- thus making the tuned pipe redundant, and increasing fuel efficiency. On the downside- the injection system would be as complicated as the engine itself... and may end up heavy or bulky-- would also certainly need to be powered electrically..... This may be detrimental to engine reliability... GD Quote Link to comment Share on other sites More sharing options...
PatPux Posted October 17, 2013 Share Posted October 17, 2013 http://www.ecotrons.com/ParaMotor_Engine_fuel_injection_kit.htmlTwo stroke injection for you simon Well having had a good look at the website, that would indeed seem to hit the mark. But I wonder what resident engine tinkerer Spigot thinks of it. Practical answer to increased power, economy and reliability or unreliable bling? Quote Link to comment Share on other sites More sharing options...
speedmouse Posted October 17, 2013 Share Posted October 17, 2013 I am half tempted to buy a kit and have a go ive got a spare 2stroker sitting about could be worth having a play . Quote Link to comment Share on other sites More sharing options...
Guest Posted October 17, 2013 Share Posted October 17, 2013 Do it dude! If it works well, I am sure you would be able to sell a fitting service to many others SW Quote Link to comment Share on other sites More sharing options...
gordon_dunn Posted October 17, 2013 Share Posted October 17, 2013 http://www.ecotrons.com/ParaMotor_Engine_fuel_injection_kit.htmlTwo stroke injection for you simon Well having had a good look at the website, that would indeed seem to hit the mark. But I wonder what resident engine tinkerer Spigot thinks of it. Practical answer to increased power, economy and reliability or unreliable bling? Very interesting! Didn't know a kit was available. The video on the site shows it installed on a Top 80 too! If it's reliable- then could be the way forward!!!! The Top80 is light enough, but if you needed to carry less fuel- then there would be an increased weight saving! GD Quote Link to comment Share on other sites More sharing options...
PatPux Posted October 17, 2013 Share Posted October 17, 2013 I wonder where this kit is actually coming from? It says Michigan USA in the contact details, but some of the language in the blurb doesn't sound as if it's written by an English speaker and the tabs on some of the web pages are Chinese Logograms! Quote Link to comment Share on other sites More sharing options...
spigot Posted October 17, 2013 Share Posted October 17, 2013 I think it's half a solution :-/ EFI in this context is just a better carb that can or should tune itself to the conditions of flight, altitude temp etc It still requires crankcase pressure and the tuned pipe to get the mixture in. Which is where we loose efficiency as Gordon pointed out so beautifully What we need is direct injection as used on modern Diesel engines. Squirt a metered amount of fuel in after the piston has passed the exhaust port and bobs your mothers brother. Sent from my iPhone using PMC Forum mobile app Quote Link to comment Share on other sites More sharing options...
ptwizz Posted October 18, 2013 Share Posted October 18, 2013 Getting back to engine requirements for flying: 1) Reliability. 2) Reliability (again, because in most powered flight, it is REALLY important.) 3) User friendliness (easy to operate, service and diagnose issues.) 4) Power/weight and other performance characteristics. I believe this is a reasonable order of priorities for most of our flying. For some types of competition, performance may come higher up the list. Quote Link to comment Share on other sites More sharing options...
myusername Posted October 20, 2013 Share Posted October 20, 2013 I'd love to see a paramotor engine based on the wankle rotary design. Quote Link to comment Share on other sites More sharing options...
gordon_dunn Posted October 20, 2013 Share Posted October 20, 2013 I'd love to see a paramotor engine based on the wankle rotary design. Parajet rotron. Quote Link to comment Share on other sites More sharing options...
myusername Posted October 20, 2013 Share Posted October 20, 2013 Nice! Quote Link to comment Share on other sites More sharing options...
pete_b Posted October 20, 2013 Share Posted October 20, 2013 You need direct injection (injector in the head) PROS Fuel economy doubles more power emissions drop to equivalent four stroke Smoother running easier starting no expansion chamber no having to mess with carb settings no fuel mixing needed CONS More electronics to go wrong high pressure fuel pump needed Air compressor needed (to atomise the fuel in the combustion chamber Oil in to crank needs sorting separate oil tank Quote Link to comment Share on other sites More sharing options...
gordon_dunn Posted October 20, 2013 Share Posted October 20, 2013 You need direct injection (injector in the head)PROS Fuel economy doubles more power emissions drop to equivalent four stroke Smoother running easier starting no expansion chamber no having to mess with carb settings no fuel mixing needed CONS More electronics to go wrong high pressure fuel pump needed Air compressor needed (to atomise the fuel in the combustion chamber Oil in to crank needs sorting separate oil tank Wow! I forgot about the expansion chamber also... definitely no need for this either.... Sounds like a nice idea- but the electrics would let the whole thing down I'm sure.... You cant beat a Top 80 with pull start for sheer simplicity!!! GD Quote Link to comment Share on other sites More sharing options...
Dariuszk24 Posted October 20, 2013 Share Posted October 20, 2013 I found this no need high pressure compressor Quote Link to comment Share on other sites More sharing options...
ptwizz Posted October 21, 2013 Share Posted October 21, 2013 Why does direct injection do away with the expansion chamber? As I understand, the expansion chamber uses exhaust gas energy to improve scavenging and volumetric efficiency. Quote Link to comment Share on other sites More sharing options...
gordon_dunn Posted October 21, 2013 Share Posted October 21, 2013 Well- if you don't need the tuned pipe, then the expansion chamber shouldn't be necessary then... I'm no expert, but i thought that the expansion chambers job was to dissapate shockwaves from the 'rebound' of the tuned pipe thus reducing noise emmissions..... GD Quote Link to comment Share on other sites More sharing options...
ptwizz Posted October 21, 2013 Share Posted October 21, 2013 The expansion chamber is an element of the tuned pipe (i'm ignoring silencing for the moment). The list of pros and cons would suggest you are proposing not only direct injection, but a supercharged 2 stoke like the Commer TS3, Napier Deltic etc. While this engine design does away with the oil in the fuel, it is not the lightest solution by a long way, especially as a small displacement single cylinder engine. Quote Link to comment Share on other sites More sharing options...
pete_b Posted October 21, 2013 Share Posted October 21, 2013 You only need a supercharger if the air does not go through the engine. The air is forced up in to the cylinder by the piston going down with the reed valves closed. The expansion chamber is tuned to push as much of the fresh air/fuel mix back in to the cylinder that has passed straight through due to the open port design of the engine. If fuel is injected after the ports are both closed then it cannot escape. Quote Link to comment Share on other sites More sharing options...
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