Power plant choice for your 3D setup
Power Plant
Brushless motors are really the way to go if you are looking for top performance and longer flight times. They require zero maintenance and have infinite life if not abused. There are 3 levels of quality in the world of brushless motors. Each level up will produce more flight time, or power, sometimes both. Size is another important factor when considering which motor to get. Smaller motors tend to require higher KV ratings. With a 1/8 inch motor shaft, up to 3000 rpm/volt is fine, and 2400 rpm/volt or less for the 5 millimeter shaft motors. On the low end, we have Mega, Jeti, Astroflight, and others. These tend to run at about 75%-80% efficiency. The Mega are a bit better than the Jeti, because they have better cooling. The 22/20/3 will get you started in entry-level aerobatics. The 22/30/3 (Jeti or Mega) is larger and should produce about 1600 RPM for about 6.5 minutes on 10 2400’s. I suggest the Jeti 40-3P ESC for these motors. In the middle range we have Hacker motors, Plettenburg, Kontronik and others. These motors tend to be different in construction from the low end ones. Hacker uses a 2-pole low inductance design that tends to have peak performance at high current draw. Plettenburgs tend to have high efficiency all around maybe due to their integrated fans (not sure). According to their site. About 90% is the norm. The B50-18S (KV of 2006 RPM/Volt) is what I use. It provides the perfect balance of power and duration for me. About 1800 RPM for 7.5 min is normal. At this current drain, there is a noticeable difference between the first and second charges (of the battery pack) of the day. I use 10 2400 NiCd cells. Another good choice is the B50-13L or the B50-11L. The 11L may burn out a 40 Amp ESC though so watch out, it is hot! At the high end there are motors like Lehner, Bittner, and Actro. As of this writing there have not been many reports on how these motors perform. Suzanne from the Ikarus bulletin board has claimed 19 minutes with a Bittner on a 10x3300 mAh pack. As reports come in, this page will be updated, so stay tuned. |
Batteries
If buying new batteries the best are Lithium Polymer cells. However they have not been seasoned and are in early stages of trials. Thunder power brand and Etech have both powered Eco 8’s with great results. Only problems are that you must a series/parallel pack, they are expensive, and you need a capable charger. Next best are the GP 3300 mAh nickel metal hydride cells. These are available in the US for $5.5 per cell. A pack of 10 cells is recommended for basic aerobatics and 12 cells for advanced. And, if you are really still a fan of nickel cadmium cells there is the 2600 mAh cell made by Sanyo. I am still running my 10x2400 packs and they are just fine, as 7.5 minutes of flight is acceptable. This page will hopefully follow technological improvements. Who knows, maybe one day we’ll be flying fuel cell powered Eco’s! |