NEU 1907 1.5Y

The following is a review of the NEU 1907 1.5Y motor. Initially some shots of this inrunner :

Introduction

The NEU 1907-1.5Y is quite a large inrunner and also a very popular motor for the Swift. The motor can be run from 4S right through to 7S. In this review I have run 4, 5 and 6S. In order to run these different voltages I used a 14 tooth pinion for 4S, a 12 tooth pinion for 5S and a 10 tooth pinion for 6S. Theoretically an eight tooth pinion would work very well at 7S.

The NEU are well known for their efficiency and I was particularly looking for this characteristic in the testing data. The motor itself has had well over 20 flights to make sure that it is both reliable and capable of handling extensive and varied flying.

In all of the flight tests below I have stuck to a routine including full pitch climb outs, loops, rolls, bunts, inverted flight, flips, hovering, tic tocs and stall turns. This should be enough to place a load on the motor and get its characteristics.

In order to record the flight data I have used a BNB products DPR 100 inflight data recorder. This is the latest generation of this inflight data recorder which includes RPM measurements. A review of this device can be found here.

The Hyperion NEU 1907-1.5Y motor has been tested with NHP 515 Razor Pro blades and MS Composit 550 mm carbon blades (for the 6S test).

Motor Stats

A quick summary is as follows :

kv : 915
weight : 8.3oz
Resistance Ohm : 0.019
IoA : 1.4

Flight Performance (4S)

I was a little apprehensive flying the NEU on a low cell count and I haven't read of anybody trying this motor with just 16 V to play with. I was pleasantly surprised with the performance delivered. Whilst it wasn't a really strong delivery it was certainly good enough to do some mild 3-D. The only maneuver I found difficult to perform was the tic toc where there just wasn't enough power to deliver the maneuver to my satisfaction. Overall the performance was competent and I was not disappointed with the motor at this voltage level. Obviously the new with it's fairly low kv is not ideally suited to 4S and this does mean running a 14T pinion in order to get the required headspeed.

The following are some in-flight graphs from the DPR 100 showing voltage, amp draw and RPM readings when performing a typical 3-D flight.

Blue is amps, green is volts and pink is rpm (*100)

As can be seen from the graph the peak amps during the flight was 57.84 amps. The average amp draw across this seven minute flight was 25.56 amps. The maximum power produced during this flight was 807 W. The maximum rotor RPM during the flight was 2012 RPM with an average RPM across the flight of 1671 RPM.

Flight Performance (5S)

At this voltage the motor seemed to be a lot happier. RPM was much more consistent and the power delivered is much more in keeping with what I would expect for a 3-D helicopter. Flying the Swift on this motor and with this voltage of pack was an enjoyable experience. Again I found myself wanting more power for manoeuvres like the tic toc but at least now the Swift was capable of performing this manoeuvre. Outside of this one issue I found the Swift very capable and it delivered a competent performance. Climbouts were strong but not ballistic, loops and rolls easily accomplished. Flips I could hear some bogging of the motor and RPM loss but nothing too excessive.

The following are some in-flight graphs from the DPR 100 showing voltage, amp draw and RPM readings when performing a typical 3-D flight.

Blue is amps, green is volts and pink is rpm (*100)

As can be seen from the graph the peak amps during the flight was 52.94 amps. The average amp draw across this seven minute flight was 24.12 amps. The maximum power produced during this flight was 893 W. The maximum rotor RPM during the flight was 2106 RPM with an average RPM across the flight of 1739 RPM.

Flight Performance (6S)

For this test I installed the MS Composit 550 mm blades. My assumption being that running 6S would give me some more power to play with. As it turned out this assumption was wrong and I discovered that for this particular motor 550 mm blades are probably a step too far. Regardless I have recorded the information from the flight below. I am sure that had I kept the 515 mm blades on the machine than the motor would have been a lot happier. I think for this size of blades it is probably better to go for the NEU 1910 series of motor.

What I found was that although the Swift was happy to fly around on these blades it did load up significantly when asked to perform 3-D. This can be seen in the graph below.

As can be seen from the graph the peak amps during the flight was 62.75 amps. The average amp draw across this seven minute flight was 24.03 amps. The maximum power produced during this flight was 1264.94 W. The maximum rotor RPM during the flight was 2132 RPM with an average RPM across the flight of 1767 RPM.

Conclusion

The one feature that stands out with this motor is its efficiency. Having run several motors on the Swift this motor definitely provides a good level of performance but at a very economical amp draw. Power delivery at 4S was acceptable but not stunning. At 5S this motor starts to come alive and the performance is really very good. At 6S I would have expected a similar good performance had I used the same blades again. Instead I changed to 550 mm blades and discovered that this is pushing the limits for this particular motor. Fortunately NEU have a larger motor in their range (1910) that I think would do a very good job on this particular blade size.

The NEU does get pretty hot and this is a fact that has worried many NEU owners. The 1907 never reached a temperature that would worry the motor, magnets or electrical system and so I don't feel this is an issue. Yes it runs hot but not so much that it is anything to be concerned about.

Overall I like this motor for its power delivery and its efficiency providing you are running 515 mm blades. As you go up in blade size this motor will start to struggle and 550 mm was definitely a step too far for a good 3-D performance without significant loss of head speed. Overall this motor comes recommended as an efficient power source for the Swift.