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  1. koyama

    Rotax 447 muffler how it works

    I am not sure this is even relevant. (I am not completely familiar with this software), however, it appears to be only for single cylinder. It does not appear to support Y pipes. As far as I can tell, unless you are building dual exhaust, this is not applicable, nor is it relevant to this...
  2. koyama

    Rotax 447 muffler how it works

    You have to be careful when comparing between sled and aircraft engines. There were a few differing versions of the sled engines made that did not have anything obvious to tell which revision you were dealing with unless you are looking at the service manual. There are also many sets of specs...
  3. koyama

    Rotax 447 muffler how it works

    The can that many people call the muffler is actually not a "muffler". It is actually a broadband expansion chamber. If you were to remove it, the 447 is nearly impossible to get started, and it will produce about 20 HP give or take. Most people that are used to 2 stroke motorcycles do not...
  4. koyama

    What aviation news, blogs or e-mail newsletters do you actively read?

    I have a few favorites, but they are all YouTube channels, I tend to focus on industry news and training related material (you should never get far from learning, no matter how much you fly). All of these have a very positive attitude and excellent quality material, here they are in no specific...
  5. koyama

    What can I do with my 582?

    I trimmed the quite above to the parts that I am going to specifically answer. It is true that there were very few engine choices during that time that were a good option for the Mini 500. But it cones down to one set of problems: Rotax specifically setup the 582 to drive a propeller, the...
  6. koyama

    What can I do with my 582?

    Your request for thoughts is hereby answered! Below are mine... I have heard many people claim that coatings could help the 582. This might be true. However, I have yet to see it demonstrated, and I can see far more problems than solutions. It is true that a coating could help with a hot spot...
  7. koyama

    What can I do with my 582?

    The 582 is a bad choice for the Mini 500. It is sad that the designer decided to go with this engine even though the factory claimed it was unsuited for the task. The 582 was intended to drive a propeller, not a rotor. With a rotor, all bets are off as to the reliability of the engine. There...
  8. koyama

    Simple six-pack replacement. Is there such a thing?

    It is true that the D-10 and D-100 have more capability than the 6 pack, but they are a direct replacement for it. Even new, they are cheaper than purchasing the same steam gauges new. If you are buying used stuff, it depends on the sources and conditions, but again, it is really difficult to...
  9. koyama

    Simple six-pack replacement. Is there such a thing?

    The reason I mentioned the D10A is that there is no shortage of them on the used market for ~$1200. That puts them in the zone where it is extremely difficult to home make anything cheaper, and if you consider your time, likely impossible. (I have about 12 of them, and I have never paid more...
  10. koyama

    Simple six-pack replacement. Is there such a thing?

    I am surprised that nobody mentioned the Dynon D10A. This is a complete, and self contained 6 pack replacement that is time proven to work. It can be setup as simple as 2 wires, power and ground, and 2 hoses, pitot and static, and you are done! It even has an internal backup battery to keep it...
  11. koyama

    Rotax 582 Alternative Possibility

    That is how I understood it. I was just using your quote to clarify that if reliability is the goal, building a one-off engine is not likely the right approach. I was getting the hint from other posts that the reason for not wanting a 2-stroke 582 was at least partially reliability. There are...
  12. koyama

    Rotax 582 Alternative Possibility

    I have seen this, however, I must point out that when driving a porpeller (not a rotor), there is no way to turn up a 582 10% and not give up flyability as I mentioned in some of my previous posts. (However, it is possible to turn one up ~10% and not give up reliability.) You are literally in a...
  13. koyama

    Rotax 582 Alternative Possibility

    You have to be careful with this, the problem is the risk of having an incorrect view of the situation. A 582 is actually very reliable and well proven. As I mentioned before, they have no real weak points, they fail because of user error. (It is the operator that is unreliable and unproven.) A...
  14. koyama

    Rotax 582 Alternative Possibility

    The only 4-stroke engine I have found that matches the weight and power of a Rotax 582 is the Weber MPE 750. If you look at this engine in detail it is obvious why. They did every trick in the book to get the weight down and the power up. The engine core is as good as you can get in this area, I...
  15. koyama

    Rotax 503 Question

    If it works, it works! I have heard many people say that they are ok, and I even examined on a 503 that someone cut the end off of one of the heads and mounted them 90 degrees so the fins were parallel with the air flow and no cowling was used and it was on a pusher. The engine obviously had...
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