MVVS outrunners

MVVS are a Czech manufacturing company with an established reputation for engineering excellence. Although the firm has been making model i.c. engines since 1952 I was still surprised to see that it has turned its resources to the electric flight scene with this, the launch of a home-grown brushless motor range.

In pursuance of the goal MVVS employed the expertise of a certain Mr. Palicka, the original lateral thinker who designed the inrunner / outrunner concept and the originator of the hugely successful Model Motors AXI range. The new MVVS operating principle is simple yet brilliant. The rotor spins outside the stator to provide the unique torque we expect from an outrunner motor but in addition there’s an external case that keeps the rotating parts out of harms way and makes the installation simpler in tight applications - such as you might encounter in a glider nose.

DIFFERENT?
I’ve been testing and flying the two smaller motors from the range labelled as 3.5 / 960 and 3.5 / 1200. This designation represents the equivalent in cubic capacity of an internal combustion engine followed by the Kv rating, i.e. the number of revs / volt. The 1200kv motor will run continuously at 35amps while the 960kv is rated at 30amps. They can each handle higher bursts, of course. Both units have a 5mm shaft with four M3 fixing points, plus a rear mount option using a kit of parts that’s sold separately.
The first noticeable difference with these motors is their striking appearance and high quality feel. The outer case has a distinctive Pininfarina type design and sensibly incorporates four generous cooling vents in the front and back to help keep operating temperatures down. Even the rotor front face has openings to keep the air passing through the entire motor. These vents are also a reason for the relatively light weight of the motors.

Unusually here, the 3.5mm Corelli connectors are solidly attached to the rear case which produces a stronger and neater ESC connection. This will be a great advantage in the nose of a glider where space is at a premium and loose cables need fastening.

The smart thinking also extends to the rotor as it’s been formed with a brass ring at the front and back of it’s drum which is recessed and let into the inside surfaces where it’s perfectly indented to anchor the high quality neodymium magnets. There’s no way the magnets can migrate so this, therefore, ensures longevity. Some manufacturers simply glue them in place where, trust me they don’t always stay put. The brass rings are doubly useful in that they provide material which can be drilled out when MVVS dynamically balance the motors. Here a tiny nibble can be taken out of the brass to achieve perfectly smooth running.

The rotor and shaft are balanced as one unit so if you need a replacement shaft you may need to send in the rotor too. If you decide to disassemble the motor, as I did, remember to mark the existing position of the two parts (with a permanent pen), before you begin.

There are a number of other very powerful and efficient motors already available in the MVVS range and interestingly they all have the same outer diameter of 31mm rising to 37.8mm at the rear of the case. The increase in power comes from the extended rotor length offering almost the same power and torque as other outrunners (which have a larger diameter to achieve this increase in power) but with the benefit that MVVS motors will squeeze into more airframes particularly where the nose is narrow and restrictive.

GOOD THINKING
One advantage of not having a rotating outer drum is that the worry of binding the fuselage or motor wires is alleviated. Other traditional brands of outrunner have their cables sprouting from the front case and these often get in the way as they’re routed past the spinning rear outer drum. This is an innovative step in the continuing evolutionary growth of the brushless motor and good news for many of my hotliners, sport gliders and prop-jets (such as the FX-27) which can very easily be given a performance upgrade with this new and improved technology.

Some final thoughts before testing: By keeping the same case diameter the back-mounting kit will fit all the motors in the current range, which is jolly good thinking. Top quality bearings are used in the front and rear of the case so altogether a lovely little 600 size motor exists here. Oh, and for what it’s worth, it’s not made in China either!

TEST DATA - MVVS 3.5 / 1200
Prop /  RPM / Current (amps)

With 8 cell 3000mAh Hi-flow NiMH
9 x 6 APC-E 9,200 22.0
10 x 5 APC-E 9,000 23.0
10 x 7 APC-E 8,100 27.0
11 x 7 APC-E 7,500 30.5
12 x 8 APC-E 6,600 36.5

With 10 cell GP2200 NiMH
9 x 6 APC-E 10,500 27.5
10 x 7 APC-E 9,200 32.5
11 x 7 APC-E  8,400 38.5

3s Li-Po 3700mAh
9 x 6 APC-E 10,270 23.2
10 x 7 APC-E   9,420 30.5
11 x 7 APC-E   8,440 38.5

4s Li-Po 3700mAh
9 x 6 APC-E  12,690 35.0

FLIGHT TESTING
I used a Multiplex AcroMaster as the test bed for these motors as this model has a varied flight envelope and it’s easy to change and remove units for comparison. I’ve used the Vortex and Hacker brands already in this machine so I had an interesting reference point to start with. Incidentally, when it comes to propping up, the APC-E brand is all I’ll use these days as they seem to be so incredibly efficient for all electric flight applications.

Should you be unfamiliar with the AcroMaster, I ought to point out that it can be used to simply fly about aimlessly having fun on minimal rate settings, thrashed mercilessly, or used to practice meaningful set manoeuvres such as harriers, prop-hanging, rolling circles, and knife-edge circuits.
I’m still teaching myself how to do these and instant throttle response is essential to make such aerobatics possible and safe. The MVVS motors have excelled in this role, inspiring and helping me to push the envelope.

The prop-hanging set piece is hard with the AcroMaster as it will not balance without a constant fight. Here, then, the additional power was noticeable. The model will hold in the vertical using a 3s 4000mAh Li-Po pack and an APC-E 12 x 8. The 960 motor uses only 29.5amps in this configuration yet belts out 7050rpm.

This motor would also be impressive in the Ripmax Spitfire and Mustang, or perhaps their new Messerschmitt 109, where an easy and quick refit would transform the model entirely. Great performance is proffered for an efficient return in input power. Thinking outside the box, I have a couple of small hotliners which use a Phasor 30 and 3s Li-Po, and they’ll be even more exciting loaded with one or other of these motors. I’ll probably fit the 1200 so I can use the existing folding prop and, truly, I can’t wait to see the improvement. Take a look at the performance figures in the two tables to whet your appetite.

WRAPPING UP
This MVVS motor delivers what it says on the box - it’s very smooth, quiet, powerful and efficient with the promise of continuing performance and longevity. Sure, it is perhaps a little dearer than some brands but less expensive than it’s counterpart in the new Hacker series, the A-30-10XL. The Vortex 42/50/750 has a little more torque as you would expect but is bigger and heavier. The MVVS more than held its own in comparison with these two other somewhat different motors. Appearance shouldn’t be anything to go by but you must admit that these little beauties certainly appeal, even when they’re sitting on the table.

Just so you know, I used the Jeti Advance 40 Opto plus ESC for these tests. This has been an excellent unit and simple to set up using the Jeti programme card (pictured below). If you need to buy a new speed controller, why not give the combination a try? Really, its never been so quick and easy to prepare a new model.

The MVVS motors are designed so that in the event of damage, usually due to a crash, the appropriate replacement parts can be supplied by the distributor to enable the repair work to be carried out quickly and easily at home. As always, John Emms at Puffin is equally pleased to offer any technical support you may need. Puffin can also supply Jeti ESCs and accesories.

TEST DATA - MVVS 3.5 / 960
Prop  / RPM / Current (amps)

10 cell GP2200mAh NiMH
10 x 7 APC-E 8,200 21.2
11 x 7 APC-E 7,600 24.5
12 x 8 APC-E  6,800 29.7
13 x 8 APC-E  6,200 33.5

3s Li-Po 4000mAh
11 x 7 APC-E 7,585 24.5
12 x 8 APC-E  7,050 29.5
13 x 8 APC-E  6,400 33.2

4s Li-Po 3700mAh
11 x 7 APC-E 8,650 32.2
12 x 8 APC-E 8,040 39.4

DATAFILE
Name:  MVVS 3.5 / 960 (30amp) and MVVS 3.5 / 1200 (35 amp)
Motor type:  Brushless cased outrunner
Manufactured by:  MVVS, Czech Republic
UK distributor:  Puffin Models
Tel. 01454 228184
www.puffinmodels.com
RRP: £75.95 - £89.95
Weight:  168g
Shaft size:  5mm

COMMENTS
Old Geezer's picture

Lovely bit of kit - flies my big old Scorpion fed by 40A ESC and a 3000 3S with bags of power to spare.

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