AXI 2826/8

The following is a review of the AXI 2826/8 motor.
My thanks to Model Motors for the supply of this motor for review.

Initially some shots of this outrunner :

Introduction

The AXI 2826/8 is a relatively small outrunner and one of the most popular motors for swifts powered by a 4S lithium polymer pack. It is not recommended to run this motor beyond this specification, however, I did run the motor with five cells just to see what would happen. This motor runs on an 11T pinion for best performance with a four cell pack.

This motor is known for producing reasonable power for basic 3-D as well as having a conservative amp draw. As this motor is such a proven solution in the Swift my task was just to gather data on this motor rather than try and prove whether it is any good or not.

For the flight tests I have stuck to a routine including full pitch climb outs, loops, roles, bunts, inverted flight, flips, hovering and stall turns. I have not included tick tocs as this motor does not have the necessary power to pull off this maneuver well.

The data has been collected using a BNB products DPR 100 in flight data recorder.

The motor has been tested using NHP 515 Razor Pro blades and M.S. composite 515 mm carbon blades.

Motor Stats

A quick summary is as follows :

kv : 1130
weight : 181g
Resistance Ohm : 0.030
Max current : 55A
Max efficency : 83%

Flight Performance (4S)

With this motor being a proven performer on four cells there is little to say other than the motor will deliver a reasonable 3-D performance for a fairly conservative amp draw. However, the motor requires that you manage the collective pitch carefully throughout manoeuvres in order to avoid bogging it down. As previously mentioned the performance is not really strong enough for an aggressive tick tock. However, it is possible to perform some fairly large rainbows with fairly gentle stops at each end. The key with this motor is not to get too aggressive on the sticks.

One thing I did notice whilst using this motor was that it does get quite hot. Various modifications have been produced to fit a small propeller to the end of the motor, one of which is in the modifications section of the site. Having discussed the temperature issues with Model Motors they sent me the cooling fan below. Having fitted this cooling fan the overall temperature of the motor was significantly better.

Another issue that was an early problem on this motor was that Castle Creations controllers would cause the motor to produce a high-pitched whine. This was resolved on the later software levels (1.51) and is no longer a problem.

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. The pack used for this flight was a Poly-Pro 4S 4350 from Overlander.

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 54.41 amps. The average amp draw across this seven minute flight was 23.62 amps. The maximum power produced during this flight was 752 W. The maximum rotor RPM during the flight was 1987 RPM with an average RPM across the flight of 1523 RPM.

Flight Performance (5S)

I tried running the AXI on a five cell pack and the results were a hotter motor but a very similar flight performance. Therefore I would not recommend trying to run this motor beyond specification.

Cooling

As mentioned earlier AXI provided a new cooling fan for the AXI 2826/8 some further pcitures can be seen below. This fan really helped motor temperatures.

Conclusion

It's always good to know that the motor you are testing has a proven track record powering the model in question. The AXI has for some time been a popular choice as it gives a reasonable performance and does so without demanding a huge amount of amps. The motor has enough power to perform most manoeuvres except those that require aggressive stick movement's or large amounts of both collective and cyclic. As an example I was not able to produce a convincing tick tock. However, this aside the AXI delivers well and is quite a small and light motor. This lightness helps the performance greatly and gives the AXI some advantage over heavier four cell motors. For those who like to study the charts the peak performance extracted from the motor was around 700 W. This is not enough for aggressive 3-D and anyone wishing to extract this type of performance from the Swift should look elsewhere at larger & heavier motors. AXI themselves have such a motor (4120/12) which can deliver a blistering performance utilising a six cell pack.

Overall this motor is an all-rounder in that it delivers a reasonable performance at a reasonable price. It is light weight and has a conservative amp draw. Therefore Swift tuning recommend this motor for those who do not wish to run larger packs but would like to start experimenting with 3-D moves on a four cell pack.