Firstly, it is totally wrong to assume that I worked from theory - take a look at MEW Jan '97 back cover - not only will you seeEZE's in development but also discover the starting point. See Neville Palmer's letter in Dec 98 MEW - it was Roy L Clough's Little Dragon of which I have made and flown many [ hence becoming familiar with it's short comings] that started off the development of the EZE series. Each one I made contained one new idea to see if it was an improvement on the previous engine, so yes, I've made a lot of these engines. In formulating the article fo EZE, John G. asked me to aim it at those who have never made an engine before. So what did I do, I asked people who had never made an engine before about what equipment and what skills they had, and then I wrote the article. The drawings were not the ones that I had submitted to John, someone [not criticising] had kindly converted my imperial drawings [I think Tom means fractional -KC] to CAD and decimal. In doing so had cocked up two things. Firstly they were done in imperial units so that a ruler could be used to make this engine as some of the would-be constructors didn't have or didn't know how to use a mike or a vernier. Secondly, a number of dimensional errors crept in.
Perhaps I should state what the concept was all about.
Criticism I welcome if constructive, uninformed opinion I am afraid I am not very tolerant of. A lot of development work has gone into the EZE series and is ongoing - I'm enjoying it. Now let me get on with the replies to the rest of the points raised. One should understand the concept of the word sport as applied to flyer. [The guy who likes to fly a small model quietly, usually in a small place. This is a SPORTS ENGINE. The word howling [success] for me gives me an insight into your ideas, maybe you have used Cox's at 22,000pm on a 5x2. This is not what EZE is about. 10,000 rpm is the aimed for figure on a 6x3/6x4 - that is what it does - keeping these figures means usually easier starting - [see comments in Bowden's book on model diesels all those years ago!] Comment on point number 2. A flat was used to keep the transfer passage volume in keeping with the rest of the design. You have milled yours concentric [difficult for a beginner or someone with limited machining. Keep the basic concept in mind. And, the comment that your engine does not sound happy, this is probably due to poor transfer pressure. I wonder if you are a "small engine person" and if you are familar with their symptoms and cures. I wonder why your engine floods easily. Perhaps too much transfer volume? Rotary valve: pressed pin - fine for someone who has built a few engines - my method is foolproof for an absolute beginner. Brass is used because it works well - I've had no failures, it machines easily and most people seem to have some in their material stores. As for weight - well if was designing something to rival a Shuriken the yes, otherwise it is just personal preference. |