DrMotor

HEAD-TO-HEAD COMPARISON OF:
Hacker A30-12L, 1000Kv
Turnigy 3542-1000Kv (12T)
HYPERION Z3019-12T, 900Kv

WHY AM I MAKING PERFORMANCE TESTS OF THESE BRUSHLESS MOTORS ?
Why am I performing these systematic and rigorous Performance Tests of 150g, "30-size" brushless motors ?
There are a number of reasons:

1. I am a Scientist and a Physician. I have published more than 200 papers in medical research. I really enjoy measuring things properly, and performing proper, precise and reliable tests.

2. There have so far been NO published controlled and precise tests of the Hacker A30-12L motor -certainly ones that I am aware of. -And this is despite the fact that this Hacker A30 motor has been around for at least 8 or 9 years -and maybe longer.
So:This is the FIRST rigorous and methodical (independent) test of the Hacker A30-12L motor that has been performed -or least that has been published.

3. The Turnigy "SK3" motors have been around for about 1 to 2 years now. They are the best quality of all the motors that HobbyKing sell. They seem quite a bit better than the Turnigy"AerodriveXp SK" motors (-the ones with black can and silver end housings) that HobbyKing sold until 1 to 2 years ago.
Certainly, there has so far been NO systematic, precise test of the relatively new Turnigy SK3 3542-1000Kv motor -at least not one that has been published, and that I am aware of.
So: This is also the FIRST rigorous test of the Turnigy 3542-1000Kv motor that has ever been performed.

4. Dr Kiwi (i.e. Dr Phil M) is very well known in our hobby for having made precise and systematic tests of a huge number of brushless motors over the last 8 or 9 years
see: http://www.geocities.ws/dr.kiwitn/ His record is incredibly impressive, and he has given a great deal of advice about best use of brushless motors, to many people over the years. However, his motor test stand is limited to motors of ~100g weight, and is suitable only for motors which generate up to about 1.5kg of Thrust.
-So Dr Kiwi has so far not been able to test motors like these 150g "30-size" motors, that can generate up to 3kg thrust, with 4S LiPo.

5. The Motor Test Stand I have built (see pic in next post) is made of metal (aluminium L-shape pieces) and is strong enough to take up to at least 600g weight "60-size" motors. It can measure up to 20kg of thrust. It can take props up to 28" diameter.

6. I showin this thread,Performance Tests of the very commonly used "30-size" motors, such as the Hacker A30-12L (1000Kv) , Turnigy 3542-1000Kv motor and the HYPERION Z3019-12T motor. All these 3 motors have a 3020 stator, all are 12 Turn (12T), and all have a quoted weight ~145g.
In later threads (to be published over next several weeks/months) I will also show systematic Performance Tests of the following:
-Several 20g / 25g "10-size" or "2122-size" motors -(1709 stator) -like the Hacker A10 L and the Turnigy SK3 2122 motors.
-Several 55g "20-size" or "2830-size" motors (2213 stator) -like the Hacker A20 L, and the Turnigy SK3 2830 motors.
-Several 175g "30XL-size" or "3548-size" motors (sometimes called "3748") (they have 3025 stator) -like the Hacker A30 XL and Turnigy SK3 3548 motors.
-Several 350g motors, or "5055-size" motors (4025 stator) -like the Hacker A50 L and HYPERION Z4025 motors.
Finally: Several ~550g motors, or "6354" motors (5025 stator) -like the Hacker A60 S, HYPERION Z5025, and Turnigy SK3 6354 motors

-I may also, in time, test many more motors than this ... but this listis good for astart ...

Lets move on ...

DrMotor

HOW SIMILAR ARE HACKER AND TURNIGY SK3 MOTORS (and also HYPERION-Z motors) ?
1. This is a further reason for performing these methodical, controlled tests of brushless motors.
There is a suspicion that many of the very best-known brands of brushless motors (like Hacker, Extreme Flight Torque, Hyperion-Z; and also many other brands) may all be made together in the SunRay Technology factory in Shenzhen, China -see http://www.rcuniverse.com/forum/m_11426913/tm.htm

2. There is also the suspicion that all these motors may actually be IDENTICAL as far as all the internal working parts are concerned, and that the ONLY difference between them is purely cosmetic e.g. a different outside colour, or slightly different style of the end housings.

3. If all these 20 or 25 "typical SunRay brands" are, in fact, identical motors underneath the outer case, then of course they will give almost identical results when they are rigorously and systematically tested on the Test Stand, under the same conditions, and using the same props.

4. In the tests in this particular thread, we will be comparing directly, under the same conditions:
Hacker A30-12L 1000Kv
Turnigy SK3 3542-1000Kv
HYPERION Z3019-12T 900 KV
-These are all 12T motors with a 3020 stator, and all have a very similar weight of ~145g. The reported Kv for the Hyperion motor is 100 lower than for the other two, and this seems surprising given that they are all 12T motors. Our test of this Hyperion motor will reveal whether it the Kv really is 900, or whether it is actually closer to 1000 ...

BIG QUESTION: HOW SIMILAR / IDENTICAL ARE: HACKER, TURNIGY SK3 & HYPERION-Z MOTORS ?

-Well, lets find out ...

DrMotor

Quick note: Why have I chosen these particular 12T 30-size motors to test ?
1. It may be thought that the Hacker A30-14L motor -a 14T motor with a Kv of 800 -is perhaps a more popular motor than the faster spinning Hacker A30-12L.

2. However, for 14T motors, there are less motors to compare with the Hacker, than there are for 12T motors see: http://www.rcuniverse.com/forum/fb.asp?m=11427116

3. For 30-size 14T motors -there is only really (in Europe) the: Turnigy SK3, Gens Ace, HYPERION, and perhaps the E-F Torque 2814T (more easily available in USA) -to compare with the Hacker 14T motor.

4. Whereaswith 30-size12T motors, we have: Turnigy SK3, LiPolice LP, OK Hobby Infinite, HYPERION, Foxy, and also the WAYPOINT-E3020-12 972Kv to compare with the Hacker. -That is why I have chosen to test 12T motors, rather than 14T.

5. There is also the additionalintriguing issue that HYPERION claims a Kv of 900 for its Z3019-12T motor, whereas all the other 12T motors all have a Kv near 1000. Proper testing will reveal the genuine Kv of this Z3019-12T motor ...

So: Here goes: Lets have some action ..

DrMotor

Final small point before we start The Performance Test:
1. In the various motor tests I will be doing, over the next few months, I will be comparing Hacker motors with same-size Turnigy SK3, Hyperion-Z, Foxy, LiPolice and Gens Ace motors. And maybe also some other typical"SunRay brands" that I will test ... (-like O.S. "OMA" motors, and Boost, Waypoint,E-FTorque and PA Thrust motors )

2. Itis only right topoint out thatsome people have expressed very huge doubts thatmotor brands such as Hacker, Hyperion-Z,Turnigy SK3, Gens Ace,etcmight even be similar motors, never mind basically identical.

3. This is shown by some of the following comments -all made over the last several months (note that just a few of the many comments that have beenmade, are shown here):

From RCU thread titled: "SK3 F3A motor-same as Hacker F3A, but 29% of cost ..?"
-Page 1 of this "SK3 F3A motor ... " thread can be easily seen on Google cache: http://webcache.googleusercontent.com/search?q=cacheB3VPL6w6mkJ:www.rcuniverse.com/forum/fb.asp%3Fm%3D11428159+SK3+F3A+motor-same+as+Hacker+F3A,+but+29%25+of+cost+..%3F&cd=1&h l=en&ct=clnk&gl=uk )
-Page 2 of this thread can be seen here: http://webcache.googleusercontent.co...&ct=clnk&gl=uk
-Page 3 of this thread can be seen here: http://webcache.googleusercontent.co...&ct=clnk&gl=uk


From RCU thread titled: "Which chinese factories make various brushless motor brands?"
.
(If by "HK junk", da Rock is referring to Turnigy SK3 motors, he is soon going to find out that he is actually quite wrong ...)


From RCU thread titled: "E-flight 160 for a Brio ?? "
( Actually, we know with 100% CERTAINTY that the SunRay Technology factory manufactures: ALL Hacker outrunner motors upto and including A60-size; and also ALL: Extreme Flight Torque, Z-series Hyperion, Turnigy SK3 motors; and also ALL Gens Ace, LiPolice, Pelikan Foxy, OK Hobby Infinite, Shulman Aviation FURY, Common-Sense-RC, Sonic Electric, Apache, motors -and also many other brands -see http://www.rcuniverse.com/forum/m_11426913/tm.htm

From RCU thread: "Turnigy SK3 motors -identical to Hacker, made in same chinese factory -25% of Hacker price ".
.
.

SO: Might: siberianhusky, Silent-AV8R, apereira, gaRCfield, tuny, Hokie Flyer, da Rock, spog1, GerKonig :
-Be right or not ...?

Both siberianhusky and spog1 commented that we need "testing and real data" for the various motors, so that we can properly compare them.

-PERFORMANCE TESTING OF MOTORS STARTS RIGHT HERE:
Seat belts on, Ready for Take Off ....

DrMotor

Here is a systematic and rigorous test of the Hacker motor:

MOTOR TEST: Hacker A30-12 L, Kv 1000 Supplied by: West London Models Price £66.20 ( =$ 101.53)
(-price is same all over Europe; in USA is much cheaper $66.99 -only 2/3 of price in Europe)

Motor Weight:143g (Hacker data)
Rated Kv: 1000 (Hacker data)
Operating current: 40A; Max current: 50A; Max power: 500W; Internal resistance: 30 milliOhm; (Aeromodel / Hacker data)
External dimensions:diam 37mm, length 42.8mm (Hacker data)(-some same-size motors are called“3742” on basis of external dimension)
Stator size:diam 30mm, length 20mm (-some same-size motors are called“3020”on basis of stator size)
No. wire turns: 12 (12T); Stator arms: 12; Magnet poles: 14; Length of magnets: 20mm (i.e. same as stator length)
Shaft diam:5mm
X-Mount (black) weight: 5.1g; Prop adaptor (bolts to hub on rear housing) weight: 17.9g; Prop driver (collet-type which attaches round shaft) weight: 16.0g

MANUFACTURED BY: SUNRAY TECHNOLOGY: http://sunraytechnology.com/
Retailer / Re-seller website:
http://www.hacker-motor-shop.com/e-v...&c=6514&p=6514
& https://www.aero-model.com/8_66_879/...-12L%20V2.html

Measuring equipment used: Eagle Tree V4 data logger with brushless RPM sensor and micro-thermistor temperature sensors (for measuring voltage, current, motor RPM and motor temperature); Additional optical tachometer; Additional infra-red thermometer. ABCON Digital scales for measuring thrust.
I used a GT-Power Watt Meter to check the current readings on the Eagle Tree data logger, especially for low currents <1A. A GT-Power Servo tester device was used to control a ZTW 70A S-BEC speed controller, which was connected to motor.
I used fully charged, 30C to 45C, 2S and 3S LiPo packs as the power source.
On the Motor Thrust test stand used, the lower horizontal arm pushes on the scales to measure grams of thrust (see photo). The props are therefore mounted on motor so that thrust is generated in a direction away from motor and stand (i.e. with front face of prop facing the motor and test stand).

Description of motor:
The Hacker A30-12 L motor, with wires and 3.5mm connectors, weighed 150.3g. The motor has a 12-arm stator (Retailer states: wound with 12 turns, 12T) and 14-magnet poles. Externally, it is 37mm diameter; the main motor body is 39mm long, and with the 11mm diam hub on the rear housing, it is a total of 49mm long (see pics). The supplied hub prop adaptor fixes around this rear hub with 4 small cross-head bolts (also supplied). The actual rotating can (i.e. the purple cylindrical part with magnets fixed to its internal face)is 22mm long, and the black rear motor housing extends backwards from this for 7mm. Motor came fitted with 3.5mm male connectors. The 4 mounting holes on what I will call the "front" motor housing are 3mm thread at 25mm centers (these are for fixing the X-mount). The motor has a 5mm shaft, of which 19mm protruded from the "front housing" and on which the supplied collet-type prop adapter can be fitted.
-One of the "give aways" of being a Sunray Technology-made motor is a brass washer and retaining black horse-shoe circlip on the shaft just outside the front housing -and of course this motor has this feature.

Standard procedure:I mounted this motor using its black aluminium X-mount (which was bolted to the "front" motor housing) onto the 8mm plywood plate of my motor test stand (see photo). I bolted the supplied hub prop adaptor to the rear housing of the motor (this has a threaded 6mm shaft) -see pics.

Standard Motor Test Procedure:
First, I ran no-loads at 11.1V (3S Li-Po) and at 14.8V (4S Li-Po), at full speed, and measured current (I), voltage (V) and RPM (no prop adaptor was attached).
I then ran 6 different props at full speed, in ascending order of size, using both 3S LiPo and 4S LiPo, and measured I, V, RPM and Thrust.
After charging the LiPo's back up again, I then ran the same 6 props, now in descending order of size, to check that the results were reproducible. The second run gave almost identical values. I wanted to get this completely right, with no errors -and so I actually made 4 runs in total; The results of each run were almost identical to each other.

Pics show:1, Motor Thrust Test Stand used; 2, Hacker A30 motor packaging; 3, Hacker A30-12 L motor and accessories; 4, Hacker motor mounted on Test Stand; 5, Rear housing of Hacker A30 motor, showing hub and 4 mounting holes for hub prop adaptor 6, props used for this motor test

DrMotor

Results:
The motor ran smoothly with all the props tested (even though current and power, in some cases, certainly exceeded the 50A / 500W Retailer max rating).
Results are shown on the attached data sheet.
-For each prop, the lower voltage reading is for 3S LiPo, and the higher one is for 4S LiPo as the voltage source.

Kv: I used two methods for calculating Kv. First, I used www.peakeff.com to calculate Kv and also Rm ("static" motor resistance); I used the 3S LiPo data values for smallest and largest props, to give the largest difference in load).
Second, I used DriveCalc to calculate ns ("real world no load speed") and Rd ("dynamic" motor resistance); DriveCalc also gives a Kv value when data is entered for a new motor (For DriveCalc, I used 3S LiPo test values for 3 different props, at very different loads).
PeakEff gave a Kv of 976; DriveCalc gave a Kv of 977, and ns of 962 -all these values were very close indeed. PeakEff and DriveCalc also gave identical values for Rm and Rd, of 58milliohms.

Current draw: When 3S LiPo was used as the voltage source, none of the props tested exceeded 50A. The 10x5 prop drew a current of 20.9A, and the 14x8.5 prop a current of 37.8A.
With 4S LiPo, almost all the props drew more than 50A (the max current rating)…! Even the 11x4.7 prop drew a current of 51.5A, and the 14x8.5 prop generated a current as high as 77.6A..

Input Power: Once again, using 3S LiPo, none of the props tested required more than 500W of input power. The largest was the 13x6.5 prop which produced 372.9W.
However, on 4S LiPo, it was a VERY DIFFERENT story. All of the props tested, between 10” and 15” diameter, required a power of more than 500W. Even the small 10x5 prop demanded 505.8W, and the 14x8.5 prop drew a power of 1016.6W -twice the max power rating given by the retailer Hacker.

RPM: Prop RPM reduced as prop diameter became larger. For all props, RPM was about 30% higher with 4S LiPo, compared to 3S LiPo.

Thrust: This 150g motor generated a maximum of 3.06kg thrust (with 4S LiPo), and that is impressive.
When 3S LiPo was used, the max Thrust was 1.72Kg, using a 13x6.6 prop. With 4S LiPo, a max thrust of 3.06kg was produced by the 14x8.5 prop.

g of Thrust per Watt of input power: In general, and for all props tested, 3S LiPo gave around 5g Thrust per W of input power.
With 4S LiPo, the values were lower, around 3.3g to 4g Thrust per W of input power. With the 2 largest props (14x8.5 and 15x8) it was only 3g Thrust per W of input power -suggesting a bit of o
overload.

RPM as % of Kv x V: Values for the smallest props were generally above 70%, and could be as high as 89% (i.e. the 10x5 prop on 3S LiPo). The 2 largest props, on 4S LiPo, only had values of 59%.

Efficiency %: This was calculated as Power OUT (i.e. power produced by motor, taking into account internal Rm losses) divided by POWER IN (Vin x Iin =Watts in). The 4 smallest props had an efficiency >70% with both 3S and 4S LiPo. The 2 largest props on 4S LiPo, only had an efficiency was around 63%, 65%.


Pic shows original datasheet, with original readings:

DrMotor

PLOTS FOR Hacker A30-12 L:
RPM vs POWER & THRUST vs POWER plots for the Hacker A30-12 L motor

1. The plots are shown below. The points are joined together in the order of increasing diameter for the 6 props tested.

2. 3S LIPO, RPM vs POWER: This shows that RPM fell as prop diameter increased. Input Power increased to the 12x8 prop (the point furthest to the right), and then Input Power fell slightly with the three larger props as RPM continued to fall.

3. 4S LIPO, RPM vs POWER: RPM fell (and Input Power increased) as prop diameter increased. For the largest prop (15x8) Input Power fell slightly as RPM continued to fall.

4. 3S LIPO, THRUST vs POWER: Both Thrust and Input Power increased up to the 13x6.5 prop(the point furthest to the right). With the 2 larger props, both RPM and Power fell from the peak with the 13x6.5 prop.

5. 4S LIPO, THRUST vs POWER: Thrust and Input Power increased as prop diameter became greater, up to a peak with the 14x8.5 prop (the point furthest to the right). With the larger 15x8 prop, both Thrustand Input Power fell from this peak.

These plots of motor performance are effectively a “fingerprint” for the Hacker A30-12 L motor.

DrMotor

Discussion of these results:
1. The results showed this motor has a Kv of 977 RPM/V, slightly lower than Retailer quoted Kv of 1000 RPM/V -but only by a small amount.
We can immediately see that the Kv must be lower than 1000, from the No-Load testing. The motor had an RPM of 16051 when driven by a voltage of 16.66V. If the Kv was 1000, then the No-Load RPM would be expected to be 16,660 (i.e. 16.66V x 1000 RPM/V).
However, Kv is only a theoretical value, calculated as if the motor was perfect with no losses. In reality, all electric motors have losses due to voltage drop across Rm and also due to thermal losses. The "real world no load speed" is a much more practical value, and was calculated by DriveCalc as 962 RPM/V.

2. The No-Load current for this motor was between 2.8A and 3.5A -this is substantially higher than the Retailer spec of 1.8A. The Rm & Rd were found to be 58milliohms, almost 2-fold higher than the Hacker spec of 30 milliohms.

3. The most striking feature of this motor test is that when 4S LiPo was used as the voltage driving source, ALL props from 11x4.7 and larger, exceeded the max current rating of 50A. And EVERY SINGLE PROP -even the small 10x5 one – exceeded the 500W max power rating. Indeed, the 14x8.5 prop needed 1016W of power, at a current of 77.6A.

4. Despite greatly overstepping the max current and power specs, the motor continued to function well at these very high levels, at least for short periods. It was noticeable that with the largest props, the current and RPM “sagged downward” from an initial peak, and settled at a steady state lower level after ~30 secs. This did NOT happen with the smaller props used. It seems very likely that this current and RPM “sagging down” is a sign that the motor was probably overloaded, certainly with the 15x8 prop.

DrMotor

CONT:
5. The current and power ratings that Hacker give their Sunray-manufactured motors, are often said to be "conservative" i.e. it is generally thought that the max current and power ratings can be exceeded by some margin, without damage to the motor. When a 4S LiPo pack was used with the 13x6.5 prop, this gave 69.2A and 920W. Perhaps a prop like this can be used, as long as the plane is not flown at full throttle ("Wide Open Throttle" -WOT) all the time, which might then damage the motor.

6. For the 14x8.5 and 14.8 props on 4S LiPo, the low values of about 3g of Thrust per W of Input Power suggest that these props may have been overloading the motor to some degree.. The fact that they also had low values for “RPM as % of Kv x V” and also for Efficiency % also suggested that with 4S LiPo, they were overloading the motor.

7. This A30-12 L motor, with a 13x6.5 prop on 4S LiPo, generated just over 3kg of Thrust for a current of 69.2A. With 3S LiPo, this prop produced a Thrust of 1.73kg for 39.5A. These would appear to be good levels of current for a 150g motor.

8. For this testing, I have deliberately used 3S and 4S LiPo packs, to simulate what we all use in the real flying situation. The usefulness of these data, is that they show -using a given prop and given number of LiPo cells - what level of current and thrust we can expect for this motor.
These data also show us what ESC might be best be used with this motor. Since this motor could generate up to 77A with larger props, it would seem that a 70A ESC and perhaps an 80A ESC might be the best option, especially if intending to use larger props.

DrMotor

CONT:
9. SO: WHAT IS A "GOOD" OR "BEST" PROP TO USE FOR THIS 150g 1000Kv MOTOR ?
a. The results of this test suggest that on 3S LiPo, a 12x8 or a 13x6.5 prop might well be best for this motor. On 3S LiPo, the 12x8 gave 1.72kg (=1720g) of Thrust for 38.2A; The 13x6.5 prop also gave 1.72kg of Thrust, but for 39.5A.

b. On 4S LiPo, the 13x6.5 looks the best. It gave 3.015 kg of Thrust for 69.2A, whilst the 14x85 prop gave hardly any more Thrust, but required 77.2A.

c. On 4S LiPo, the 15x8 prop gave less Thrust than the 13x6.5, for about the same current draw.

10. APPLICATIONS OF THIS MOTOR:
AeroModel state: "The New A30 V2 series motors are designed for Larger Parkflyers, 3D-Aerobatic, Scale models and Helicopters using 2 to 5 series LiPoly batteries " - https://www.aero-model.com/8_66/Moto...30-Series.html

a.. AEROBATIC PLANES:
A 150g motor like this Hacker A30-12 L would typically be used in Sebart 30-size planes (~1.3m wingspan) which have a 1.4kg flying weight - http://www.sebart.it/30E-class.html
Similar planes to this are 3D Hobby Shop 48” wingspan planes - http://www.3dhobbyshop.com/3D-Aircraft_c_189-1-1.html
or: Extreme Flight Vanquish, Precision Aerobatics 50” wingspan planes which have a flying weight 1.2kg to 1.4kg.
In planes like this, this Hacker motor on 4S LiPo will give these planes a 2:1 Thrust to Weight ratio. -Now, that is fun ...

b. SLOWER FLYING PLANES and SAILPLANES
This 150g 1000Kv motor can be used in slower flying planes and scale-type planes -probably up to ~1.6kg with 3S LiPo, and up to ~2.5kg with 4S LiPo.
For sailplanes: Esprit Models make some recommendations - http://www.espritmodel.com/hacker-a30-12l-motor-v2.aspx -and suggest that this motor might be suitable for a 2m sailplane like the Great Planes “Spirit ARF” which has a flying weight of ~1.2kg. They suggest a 12x6 folding prop.

BEST PROPS for this motor:
12x8 on 3S LiPo
13x6.5 on 3S LiPo
13x6.5 on 4S LiPo

DrMotor

NOW:THE BIG QUESTION: -HOW does the Turnigy SK3 3542-1000Kv COMPARE with the Hacker A30-12 L motor ?

MOTOR TEST: Turnigy SK3 3542-1000Kv-Supplied by: HobbyKing (HK): Price $27.76
(-Compare with price of the Hacker A30-12 L motor -which costs $ 101.53 in Europe (=£66.20); -and $66.99 in USA )

I WILL GIVE THE BOTTOM LINE ANSWER TO THE MAIN QUESTION, RIGHT AT THE START OF THIS MOTOR TEST:
-As you will no doubt see below, from this careful, objective and rigorous test:
The Turnigy SK3 3542-1000Kv turns out to be A TOTALLY IDENTICAL MOTOR- in every single way -to the Hacker A30-12 L motor.
-Indeed, all the scientific testing and all the de-construction of the motor carried out in these tests, shows that underneath the outer case, the Turnigy SK3 is actually the EXACT SAME MOTOR as the Hacker A30-12 L (-they are both, of course, made side-by-side in the same SunRay Technology factory in Shenzhen ...).
-Indeed, as you will also see, the Turnigy SK3 - in some respects - is actually a better motor than the Hacker …!
-The only real difference between these two motors is that the Hacker is purple on the outside, whilst the Turnigy is chrome ...

-And let us also note, once again: The Turnigy SK3 3542 only costs 27% of the totally identical Hacker A30 motor …

Read on …

MOTOR TEST: Turnigy SK3 3542-1000Kv:
Motor Weight:141g (HK data)
Rated Kv: 1000 (HK data)
Max current: 45A; Max power: 670W; Internal resistance: 31milliOhm;(HK data)
External dimensions:diam 37mm, length 44mm(HK data -despite D37, L44, HK still call it a "3542" motor) (-some retailerscall ita“3742” motor)
Stator size:diam 30mm, length 20mm (-some same-size motors arecalled a “3020” motor on basis of stator size)
No. wire turns: 12 (12T); Stator arms: 12; Magnet poles: 14; Length of magnets: 20mm (i.e. same as stator length)
Shaft diam:5mm
X-Mount (black) weight: 5.1g; Hub Prop adaptor (bolts to hub on rear housing) weight: 10.2.g; Prop driver (collet-type which attaches round shaft) weight: 11.3g

MANUFACTURED BY: SUNRAY TECHNOLOGY: http://sunraytechnology.com/
Retailer / Re-seller website: HobbyKing:
http://www.hobbyking.com/hobbyking/s...ner_Motor.html

Measuring equipment used: -Exactly same as for Hacker A30; No need to repeat.

Description of motor:
The Turnigy SK3 3542-1000Kv motor, with wires and 3.5mm connectors, weighed 141.1g. The motor has a 12-arm stator (Retailer states: wound with 12 turns, 12T) and 14-magnet poles. Externally, it is 37mm diameter; the main motor body is 36mm long, and with the 11mm diam hub on the rear housing, it is a total of 43mm long (see pics).Thesupplied hub prop adaptor fixes around the hub with 3 small cross-head bolts (also supplied). The actual rotating can (i.e. the chrome cylindrical part which hasmagnets fixed to its internal surface) is 22mm long-exactly the same length as for the Hacker purple rotating can.The rear motor housimng extends back for 3.5mm from the can(see pics). Motor came fitted with 3.5mm male connectors. The 4 mounting holes on what I will call the "front" motor housing are 3mm thread at 25mm centers (these are for fixing the X-mount). The motor has a 5mm shaft, of which 21mm protruded from the "front” housing and on which the supplied collet-type prop adapter can be fitted.
-One of the "give aways" of being a motor manufactured at the Sunray Technology factory -is a brass washer and retaining black horse-shoe circlipon the shaft just outside the front housing -and of course this Turnigy SK3 motor has this feature.

Standard procedure: Same as for the Hacker motor; No need to repeat.

Standard Motor Test Procedure:
-Exactly same as for Hacker; No need to repeat.
I wanted to get this motor test completely correct, with no possibility for error. So I actually made 4 runs in this motor as well, so that I could be totally confident of the results. All 4 runs gave readings which were almost identical. Therefore, I am very confident of these results.


Pics show: 1,2, Turnigy SK3 3542 box and packaging; 3,4, Turnigy SK3 3542-1000Kv motor with supplied accessories;5,6, Turnigy SK3motor mounted on the Test Stand.

DrMotor

Results: for Turnigy SK3 3542-1000Kv
The Turnigy SK3 3542-1000Kv motor ran smoothly with all the props tested (even though current and power, in some cases, certainly exceeded the 45A / 670W max rating given by the retailer, HK).
Results are shown on the attached data sheet.
-For each prop, the lower voltage reading is for 3S LiPo, and the higher one is for 4S LiPo as the voltage source.

Kv: As before, I used both www.peakeff.com and DriveCalc to calculate Kv, Rm ("static" motor resistance) and Rd ("dynamic" motor resistance).
-PeakEff gave a Kv of 1008; DriveCalc gave a Kv of 1040, and an ns of 1023 -all these values were very close indeed. PeakEff and DriveCalc gave values for Rm and Rd, of 77 and 70 milliohms respectively. These were also close.

I am not going to describe the results of testing the Turnigy SK3 3542-1000K in any detail. There is just no point, because this Turnigy SK3 motor gave ALMOST IDENTICAL RESULTS to the Hacker A30-12 L motor. And I have already described the results for the Hacker motor (in posts #7, 8 & 9 of this thread).
Therefore, I am just going to focus on the great similarities, and also a few minor differences between these two motors:

MOTOR PERFORMANCE ON THE TEST STAND:
a. If we compare the datasheets for the Turnigy SK3 3542-1000Kv and the Hacker A30-12 L motor, we can easily pick out some values for comparison:

Current A) RPMThrust (g)
For the 10x5 prop with 3S LiPo:
Turnigy SK3: 19.9 9290 1150
Hacker: 20.9 9390 1190

For the 11x4.7 prop with 4S LiPo:
Turnigy SK3: 51.2 10250 2620
Hacker: 51.5 10180 2650

For the 12x8 prop with 4S LiPo:
Turnigy SK3: 59.5 9450 2650
Hacker: 61.4 9480 2760

-Very obviously, there is no need for us to go on; It is very clear that within the limits of experimental error, the performance of these two motors is is COMPLETELY IDENTICAL.
-For each prop tested, the current, input power, RPM and Thrust readings were almost identical for the two motors.

DrMotor

PLOTS COMPARING performance of Turnigy SK3 3542-1000Kv& Hacker A30-12 L motors

The fact that the the Turnigy SK3 and the Hacker A30 are, in reality, identical motors underneath their outer case, is confirmed completely by the graphs shown below.

a. 3S LiPo plots: In the first 2 plots below, I have compared the two motors for 3S LiPo, and have plotted RPM vs Power,and Thrust vs Power. In the left plot, orange symbols are for Hacker A30, blue for Turnigy SK3. In the right plot, green symbols are for Hacker, red for Turnigy.
-You can see that the graphs for the Turnigy SK3 3542-1000Kv and the Hacker A30-12 L almost superimpose on each other.

b. 4S LiPo plots: In the second 2 plots, I have compared the two motors for 4S LiPo, and have again plotted RPM vs Power,and Thrust vs Power. In the left plot, yellow symbols are for Hacker A30, blue for Turnigy SK3. In the right plot, red symbols are for Hacker, blue for Turnigy.
-Once again, you can see that the graphs for the Turnigy SK3 3542-1000Kv and the Hacker A30-12 L almost overlay on each other.

The Turnigy SK3 3542-1000Kv has EXACTLY the same performance as the Hacker A30-12 L motor.
Therefore, underneath the outer chrome or purple case, the Turnigy SK3 3542-1000Kv is EXACTLY THE SAME MOTOR as the Hacker A30-12 L motor.

DrMotor

PHOTOS COMPARING OUTSIDE OF THESE TWO MOTORS,ANDACCESSORIES:
Here are some photos comparing the Turnigy SK3 3542-1000Kv and Hacker A30-12 L motors side by side.

a. The SK3 and Hacker motors have slightly different front housings.

b. The SK3 and Hacker motors have different rear housings. The Hacker rear housing extends further back than the SK3 one. However, they both have the same 11mm diam hub on the rear housing. It should be noted that the style of front and rear housings is just cosmetic, and does not affect the performance of the motor.

c. The SK3 and Hacker motors have almost IDENTICAL accessories. The black X-mount is the same identical part,for both motors.
-The only minor difference in accessories is that the Hacker hub prop adaptor attaches to the rear housing with 4 small cross-headed bolts, whilst the SK3 attaches with 3 cross headed bolts. Also the SK3 prop adaptors are 7g lighter than the Hacker prop adaptors (compare the weights I have measured, for both motors).

d. Oh, I almost forgot: The Hacker has a purple rotating can with black end housings; The Turnigy SK3 has a chrome rotating can with silver end housings; -But then details like this arejust cosmetics, and nothing more …


Pics show: 1, Front housing of motors; 2, Rear housing of motors; 3, Two motors compared from side view; 4, Accessories supplied; Hacker ones on left, Turnigy SK3 on right. The black X-mount supplied for each motor, is clearly the same IDENTICAL part, and must come from the same factory ...

DrMotor

PHOTOS COMPARING THE INSIDE OF THESE TWO MOTORS

Here are photosshowing the inside of the Turnigy SK3 3542-1000Kv and Hacker A30-12 L motors, after the front circlip is removed, and the rotating can is removed from the stator. -This now explains why their performance is identical,because INSIDE (as you can see) -THESE TWO MOTORS ARE COMPLETELY IDENTICAL ...

a. They both have an identical 3020 stator -i.e. a stator which is 30mm diam, 20mm long. Both stators have 12 “arms” or “slots”.

b. The stator is wound identically for both, and with the same copper wire.

c. They have identical bearings.

d. They have a basicallyidentical 5mm shaft. (-The Hacker shaft is very slightly longer (67mm) than the Turnigy SK3 shaft (63mm) because the Hacker motor itself is slightly longer -due to the deeper rear housing. However, the length by which the shaft protrudes from the front of the rotating can (31mm ) is exactly the same in both motors. And the distanceofthe circlip goove from the front of the shaft is alsoidentical between these motors).

e. They have an identical diameter can, both made with exactly the same thickness aluminium

f. They both have 14 magnet “poles”, and the 20mm long magnets are identical in both motors.

g. AndBOTH of them motors have CURVED MAGNETS -i.e. magnets which are curved on their interior surface, which is the surface facing the stator (“Curved magnets” have always been a “headline marketing feature” of Hacker motors ...).

h. AndBOTH of the motors havedynamically balanced rotating cans -we can see this easily in pic 5, which shows the blue plastic deposits that are added during the can balancing procedure in the factory.

CONCLUSION: Once these two motors are taken apart, and we can see the inside (the “guts” of the motor… ), it becomes extremely obvious that the Turnigy SK3 and the Hacker A30 are TOTALLY IDENTICAL AND EXACTLY THE SAME MOTOR.
Of course, this is precisely why the two motors produced exactly the same performance on the Test Stand ...


It is worth making the point here, that of course -we would never guess from the outside appearance of these two motors, that they are EXACTLY the same inside and that they have exactly the same performance (-and especially because the Turnigy costs $27, whilst the Hacker is $101… )
-And of course this is precisely why allthe 20 or 25 or 30 different “SunRay Tech motor brands” all have a slightly different outside appearance. It is to try and prevent us realising that these motors are, in reality, all exactly the same on the inside.
-Clearly, the SunRay factory and also the re-sellers of these SunRay motors (-like Hacker, Extreme Flight, Common-Sense-RC, BMI-Models,etc etc) do not wish us to realise that Hyperion-Z,Gens Ace, Turnigy SK3, LiPolice, OK Hobby Infinite, Pelikan Foxy,Common-Sense-RC,BMISpitz, motors -are all, in fact,totally identical to Hacker motors, and to Extreme Flight Torque motors... (-on the inside ...)

But the fact is, they all are ….



Pics show: 1, 2, 3, Stator and windings of the 2 motors;Turnigy SK3 on left, Hacker on right; 4, Inside of rotatingcan; Turnigy SK3 on left, Hacker on right;Both motors have magnets which are curved on theinner surface; 5, Rotating can of both motors, to show that they are bothdynamically balanced (note blue plastic deposits between the magnets; Obviously, the Hacker is the purple one ..The actual can part is the same forboth Hacker and Turnigy SK3 -it is just that the Hacker has a wider rear end housing than the SK3.
6,Closeup view of the front housing of both motors

DrMotor

CONCLUSION OF OUR INVESTIGATION.

1. The Hacker A30-12 L motor is the EXACT SAME IDENTICAL MOTOR as the Turnigy SK3 3542-1000Kv motor.

2. The Hacker motor might be be purple on the outside, and have a different style rear housing, and have a hub prop adaptor which attaches with 4 bolts rather than 3.

3. However,features such as this are purely cosmetic; -And nothing more. Cosmetic features like this have NO effect on motor performance.

4. On the INSIDE, underneath the outer case, the Turnigy SK3 and the Hacker motors are COMPLETELY IDENTICAL.

5. Under the same conditions on the Test Stand, the Hacker A30-12 L and the Turnigy SK3 3542-1000Kv motors give identical readings for current, power, RPM and Thrust,
-This proves unequivocally, and beyond a shadow of a doubt, that the Turnigy SK3 3542-1000Kv and the Hacker A30-12 L are actually the EXACT SAME IDENTICAL MOTOR, as far as the internal working parts of the motor are concerned.

6. The Hacker A30-12 L motor costs $101.53 -all over Europe (=£66.20 in Queen Elizabeth's currency ... ); and this Hacker A30 motor costs $66.99 in USA.

7. However, the completely identical Turnigy SK3 3542-1000Kv costs only $27.76 from HobbyKing.

8. The Turnigy SK3 3542-1000Kv and the Hacker A30-12 L are the EXACT SAME IDENTICAL MOTOR, in all important respects.

-However, the Turnigy SK3 is only 27% of the cost of the Hacker A30 motor

DrMotor

Who would have imagined that:

A brushless motor costing $101

is EXACTLY THE SAME IDENTICAL MOTOR

-as another same-size motor costing $27 ... ????

But that is the situation we very clearly have ....

Make no mistake: As far as brushless motors are concerned, We are most certainly NOT " ... getting what we are pay for ..."

We might normally think: That the quality of an item might increase as the prices increases
-NOT IN THIS CASE ....

We might normally imagine that the more one pays for an item, the better the merchandise
-NOT IN THIS CASE ....

rosnik

Interesting write-up, thank you!

DrMotor

Hello rosnik, Thanks very much for this comment.
The thread seems to have a good start.-However, as I am sure you can see,some posts are actually MISSING from this thead at the moment.
Your post is #17. And this oneis post #18.
At the moment, post #10 is missing. And so are posts #14, #15& #16.
This is not good at all;
-Post #10 shows several photos of theTurnigy 3542-1000Kv motor;
-And post #14 shows severalphotos of the INSIDE of both the Hacker and Turnigy motors, showing that their stators andmagnets, bearings and shafts etc are completely identical.
-This explains totally, why these two motorshave the very sameperformance figures on the Test Stand, because they are actually completely identical motors, underneath the outer case .....

I am not sure at all, why these 4 posts are missing from this thread, at the moment.

aeajr

My Feedback: (2)

The posts are missing because you are under moderation and they will not appear until a moderator approves them.  I have just approved them.  But if you go back and edit them they will disappear again until they are approved again.

DrMotor

Posts: 10, 14, 15 & 16 -can now be seen.

- I have no idea at all, why posts 11, 12, 13, appeared before post 10 did ...
It's a mystery ...

DrMotor

CAN PEOPLEPLEASE TELL ME:

Which do they think are themost popular RC / aeroplane / brushless motor forums ..?

What is your opinion ?
Please, who-oever reads this thread,
PLEASE: Justmake a very quick 1 or 2 word small post / contribution about this ...
Many Many Thanksfor doing this. I am grateful to all of you, for assistance.


( -I know this thread has had ~600 views inless than 24 hours, so I can see hundreds of people must beviewing this thread ... -So please DOcontribute... )

DrMotor

CORRECTION:
-I have corrected post #10
-By mistake, I gave the length of the Turnigy 3542-1000Kv as 48mm, and the stator as 3025 (have NO idea why I did this .. ).
Of course,this motor is 42mm long(-that is why it is called a "3542" motor ... )and it has a 3020 stator -just likethe Hacker A30-12L &HYPERION Z3019-12T

-And also just like these 12T, ~150gmotors:
LiPolice LP-3020/12T-970KV
OK Hobby Infinite A3020-970, 12T
Foxy C3020/12 970Kv
Pilotage Nova Line DT3019/12 970 Kv
Lipotech GTA 20-12 900 Kv, 12T
WAYPOINT-E3020-12 972Kv
O.S. OMA-3820 Kv960

-In all probability,these are all totallyIDENTICAL motors to the: Turnigy 3542-1000Kv, Hacker A30-12L & HYPERION Z3019-12T
( -they are,of course, ALL manufactured side-by-side inthe SunRay Tech factory ... )

DrMotor

ALSO CORRECTED POST#4
-By mistake, also gave wrong length and stator size for Hacker A30-12L (what is going on ...?) !!
-Of course, this motor is 42mm long, and has a 3020 stator ...

DrMotor

Another small correction topost #4
-The Hacker A30-12 L has magnets which are 20mm long-magnets are aways same length as the stator, &the stator is 3020...

(when I made original post, I must have been thinking of the Hacker A30 XL motors, and the Turnigy 3548 motors ...! )