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can773 -> RE: Plettenberg 25-12 Evo? Is it enough for most? (11/23/2009 9:45 AM)
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Hey guys, Wow, this thread got busy :) I have been elbow deep in flooring reno's on my house and just getting to RCU today :) So way back in '05 I flew a 25-13 on an Enigma. Compared to an Integral that plane had a dinky fuse...wings probably a little bigger, but not at thick. That model was about 10.25 lbs with that motor. We were running the original TP 5300's on 19x12W props, spinning about 6200-6300 rpm and 70-75A. We could run the 19x12 standard blade but the amps were just a little high and at the time the only controller Schulze had was the 32.55, the 80 was yet to made for use in pattern. Flying FAI that setup really struggled, you could do it, but you didn't have any room for mistakes or you didnt have enough power of the tops. I flew that at the '05 Nats, and did ok but was not happy with the performance. The motor was running really hot as well which made it tricky to make sure things would not fail (I never failed a motor, but others did). After the Nats I changed to the original 30-10. This was much better compared to the 25-13. Although the 30-10 had a few less watts input and less RPM than the 25-13, it was doing it with the 21" props and so it had much better pulling power. Overall weight of the Enigma was maybe 10.3 lbs with that motor in it so still pretty light. I flew the 21x13W mostly after that, since I made that change after the Nats and only a few weeks before the '05 Worlds I just didnt have much time to get the exact setup nailed (should have used a 21x14 in hindsight!). It was really windy in France, and my 21x13W was really slow, but still way better than the 25-13 motor would have been. I flew so slow I almost went over time on one flight, I think I landed with less than 2 or 3 seconds left to the 10 min. mark. The Pletty's attended that Worlds and we spent lots of time with them, they were very interested in pursuing a motor for pattern, and the 30-10 Evo seeds were planted :) There were major changes from the 30-10 to the Evo, stator geometry (you will notice the stator near the center is slotted), windings were done differently, fewer poles, different stator material, and I am sure some others. A lot of this was leveraged from Pletty's work in big motors like the Predator. About a month before the 2006 US Nats myself and Adam G. got prototype Evo motors. There was a weight gain on these to the original 30-10, but the increase in power offset that :) After that I never looked back and still use that motor to this day. The new 25 Evo motors will share the same tech that the 30 Evo has. The motors are shorter I believe which will make the stator shorter, so there is no way they will generate the torque that the 30 Evo can make. They will have more power than the early 25-13 did for sure. I have never tried one, and probably wont, I think it would make a fantastic motor for a bigger 110 size model that you would run 10s on, but I don't think they are suitable for a modern 2m F3A plane. Sooner or later you will be in a situation where you need the power and it wont be able to deliver it. The 30 Evo may seem excessive, but its really just learning to manage the power, there are always occasions where you will need the power, and you will be happy to have it! Re: Props and prop couple. I have never used the spinner mounted motor system. Mainly because I want to be able to run any prop, so preferred a conventional firewall mount to keep options open. Thats why I made the hub so I could try the folding props without giving up options :) I like the folders and plan to keep running them, but if something comes along better then I can change easily. Prop is such an important aspect when flying electric I think its important to keep evaluating this and you can't do it when you are tied to only one setup. I don't want to take anything away from Pletty's setup, its a very well designed system and works great. Bernd Berschorner has used it for many years with great success, its just not how I want to do it. One point, you cannot use the vector steer (thrust vector) setup unless you use the spinner mounted motor!. Hope that helps a bit? :)
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