Test Results

Table 1 presents results from tests of all motors with 6.7:1 gearing and GWS 5x3 prop. Within the Didel pager motors group we can see that the lower ohm motors generate more thrust, and also have a higher amp draw. The 3.2 ohm motor has an amp draw of 0.58, which would be too high for the E-Tec 90mAh cell's 0.5 amp max discharge rate. More importantly this motor runs hot and its static thrust quickly declines. This prop and gearing is clearly too much for this motor. The 4.5 ohm motor, however, has a substantially lower amp draw of 0.33, well under the E-Tec 90's max amp draw. Moreover it does not run hot and generates virtually the same 14.7g thrust as the hotter wind 3.2 ohm motor. Moving to the 6.0 ohm motor the amp draw is almost the same as the 4.5 ohm motor, but its thrust is substantially lower at 10.5g. The higher 8 and 10 ohm motors have substantially lower amp draws of 0.21 and 0.18 amps respectively. But, their thrust is substantially lower at about 7.7g and 7.5g. Clearly within the Didel pagers the 4.5 ohm motor is in the sweet spot in terms of maximum thrust without overheating or exceeding the E-Tec 90's amp limit. The 10 ohm motor is also clearly best where lower thrust is required but low amp draw is important. Finally, the 7mm pager develops roughly the same thrust as the 10 ohm motor, but pulls the same amps and weighs nearly twice as much. It just doesn't measure up compared to its smaller siblings.

Overall the Bit Clone motors do not perform as well as the Didel motors. The white bell Snow Globe motor has the same 4.5 ohm resistance as Didel 4.5 ohm motor. However, it pulls 0.44 amps compared to the Didel's 0.33 amps. And, it develops a gram less thrust and runs hot. Although I've tested several of the Didel 4.5 ohm pagers with equivalent results, this is the only Bit Clone motor I have with this resistance. However, other people seem to be finding similar results for the Didel motor outperforming the Bit Clone motors. The hotter wind 3.7, 3.3, and 2.6 ohm Bit Clone motors ran very hot and burned out within a minute. The similar resistance Didel 3.5 ohm motor runs warm and does not immediately burn out. Again, the Bit Clone motors do not seem to perform as well as the Didel motors. However, if the Bit Clone motors are equipped with smaller props they might last longer, although developing less thrust. Overall, the 3-motor ZipZap hop-up package does not seem that useful to me. Two of the motors have too hot of winds and quickly burn out and the third doesn't have a hot enough wind and develops less thrust than the Didel 4.5 ohm pager.

The Bit Char-G and Mabuchi motors are not coreless. The Mabuchi pulls slightly more amps and develops less thrust than the equivalent 10 ohm Didel. The higher resistance Bit 2.2 motor pulls more amps and develops less thrust than the Didel 4.5 ohm motor. Clearly the coreless motors have the advantage here.

Within the general surplus motors the Namiki shines and develops equivalent thrust to the 10 ohm Didel. This motor has been known for a while to be a good pager motor and this confirms it. Still, it does not develop the thrust that the 4.5 ohm Didel does. The brown bell surplus motors are the ones often available from general electronics surplus houses. In addition to being heavy, and having a non-standard 6.1mm case, they don't perform well either. They have relatively higher amp draws for their resistance and develop only typical thrust.

One last way to characterize all these motors is by some simple figures of merit. What we see is that the Didel 4.5 ohm pager has a very high thrust/weight ratio and also a high (thrust/weight)/amps ratio. The other motors with higher values on this measure, which considers both weight and amp draw, have substantially lower levels of thrust. Since the E-Tec 90mAh cell can easily handle the amp draw of the 4.5 ohm Didel this motor overall looks like the best choice for a 6.7:1 gear ratio and 5x3 prop.