Multiplex AcroMaster Pro RR

2

Fifteen years after the introduction of the wildly popular Multiplex AcroMaster, a new, updated version has taken its place and it’s a winner.

Please join me in welcoming the new Multiplex AcroMaster Pro RR, a receiver-ready model which pays homage to the original, but with many new features and upgrades. Chief among these are an innovative wing locking system, a quick-release battery securing system, improved motor mount, anodized aluminum undercarriage, larger wheels and improved inner fuselage structure.  A ROXXY 75-amp ESC, ROXXY 990Kv brushless outrunner and a full compliment of Hitec analog servos, both with metal gears and Hitec’s excellent “Karbonite” composite gears round out the package.  There’s even a 12×6 electric prop which appears to be a clone of an APC brand without the “APC” lettering.

It is always a pleasure working with Suzanne Lepine, director of marketing for Hitec RCD in Poway, California.  When Suz offered this model for review and I saw what it’s all about on paper, I had to say yes.  Guidance comes from a Hitec Flash 8 radio while the electrons originate from Lectron Pro batteries courtesy of Kenzier Lemmons of Common Sense RC in Chatsworth, California.

Drone enthusiasts, please note that these batteries are listed as an upgrade to the DJI Phantom!

During the course of writing this review, I learned that Kenzier would be leaving the company.  Her replacement, Nathan Bannister, is a terrific gentleman with whom I’ve worked before.  I wish Kenzier the best!

While aimed squarely at advanced fliers due to its aerobatic and 3D capabilities as well as precision control for IMAC competition, the Pro is an outstanding platform for intermediate pilots to hone aerobatic flying skills.  Since most of the “hard work” is already done at the factory, an evening or two of final assembly and setup is all that are needed to get this model in the air.

Specifications

Wingspan: 43.3″ (1100mm)

Length: 45.28″ (1150mm)

Flying weight: 47.62 oz (1350g)

Center of gravity:  110mm behind the leading edge of the wing

Construction:  Multiplex “Elapor” foam airframe, wheel pants and spinner; carbon fiber wing spars; plywood battery tray and “wingstabbi” wing retainer; nylon propeller; nylon hook-and-loop straps; steel, aluminum and plastic hardware; plastic and foam wheels and tires; aluminum main landing gear strut with plastic mounting block

Motor: Multiplex ROXXY C35-48 990Kv brushless outrunner

 ESC: Multiplex ROXXY 75A BL-Control 755 S-BEC with Multiplex battery connector

Propeller: 12x6E nylon

Servos: Two Hitec HS-82MG metal-geared analog servos for elevator and rudder; two Hitec HS-65HB Karbonite-geared analog servos for ailerons

Radio as tested:  Hitec Flash 8 eight-channel computerized aircraft

Receiver as tested:  Hitec Optima 6 six-channel aircraft

Batteries as tested: Lectron Pro 2700mAh 3S 35C lithium polymer with XT60 connector

Operator skill level/age:  Intermediate/advanced; 14+

US distributor:  Hitec RCD USA, Inc., 12760 Danielson Court, Unit E, Poway, California 92064

Catalog number:  M100846

 Available from: Hitec Weekender Warehouse or any hobby shop which distributes Hitec and Multiplex products

Price (USD):  $279.99

Contents

The AcroMaster Pro comes as a nearly complete package:

  • Servos and linkages installed in the fuselage and wings
  • Motor and ESC already installed as well
  • Assembled undercarriage
  • 1.5mm Allen wrench
  • Undercarriage mounting screws (more on those in a bit)
  • Adhesive-backed hook-and-loop tape
  • Illustrated assembly manual in German, French, Spanish, English and Italian

Needed to complete:

  • Computerized aircraft radio system with four or more channels
  • 2600 – 2700mAh 3s lithium polymer battery (ROXXY Evo 2600 40C or equivalent)
  • Lithium polymer-compatible battery charger
  • Decal sheet in either red or yellow
  • Regular medium CA or Multiplex Zacki if available
  • 10mm socket wrench for installing the propeller collet
  • Spray bottle of soapy water for applying the pressure sensitive decals

One thing Multiplex does well is packaging, whether from Germany or in this case, China.  The brightly colored display box has a wealth of information about the model and what will be required to fly it.  Inside is just as nice; with all parts securely bagged and taped to the inner packaging.

Even the manual and an addendum got their own bag:

Speaking of parts, I have a lot of experience with Hitec servos; they’re among the best money can buy.  I’m experienced with both the HS-82MG metal-geared servos and the HS-65HB Karbonite-geared versions and they’re well matched to this airframe as I would later discover.  However, I would really enjoy seeing a version with digital servos or even no servos at all.  If one is using a Hitec radio, the Maxima line of receivers is not compatible with analog servos…and I have two new Maxima receivers on hand.

The airframe components themselves, as I’ve come to expect, were smoothly finished with only the barest minimum of injection marks.  Even the solid foam canopy was painted a cheery shade of sky blue; my beloved ParkMaster Pro (which I reviewed for another site and which was reviewed here for RC Universe) had a canopy molded to the fuselage, requiring the fuselage be masked and painted.  I’ll skip ahead and share this family portrait I snapped on my phone on behalf of a friend while evaluating the AcroMaster:

In any event, Elapor molds into a smooth, beautiful finish which requires little painting, if any.  Should one choose to add paint accents, Testors Model Master spray paints work perfectly, the propellants won’t damage the foam and it makes for a very rugged finish.  It’s what I used on the ParkMaster.

I neglected to get a picture of the wings in their bags, but here’s everything else:

What the model doesn’t include is a decal sheet; in the case of the AcroMaster, a set of three large, die-cut sheets.

This in my opinion is an excellent marketing move.  Dealers won’t be on the hook for keeping a model with an unpopular color scheme in stock and it opens the door for a wealth of aftermarket decals.  In my experience, there is no better choice for custom work than Callie Soden of Callie Graphics in Magdalena, New Mexico.  She’s simply the gold standard in model graphics.

Assembly

Assembly begins with installing the keyed elevator and rudder with some CA.  The parts are self-aligning and later measurement showed them to be perfectly square. The key for the horizontal stabilizer is visible in this shot of the tail prior to its installation:

This is as easy and as accurate as it gets:

Next comes the undercarriage with its two self-tapping 2.9 x 16mm screws holding them in place.

Easy, right?  Wrong.

The screws were an exceptionally tight fit and both sheared off flush with the mounting block before I could fully remove them.  This meant I had to drill new holes for a couple of #6 x 3/4″ sheet metal screws.  I’m actually glad when things like this happen and so too was Suzanne.  She’s promised to bring this and other minor QC issues to the attention of the factory.  End users should install their screws with the help of a bar of bath soap or by carefully reaming the holes in the mounting block.

In my attempt to attach the pushrods to their respective servo horns, I found that the barrel connector for the rudder had not been tapped all the way through.  Easy enough to fix with a 3mm tap, but here was the second hardware issue in as many steps, totally uncharacteristic of Multiplex.

The wings and their dual carbon fiber spars are next.  This is where some really innovative designing comes through in the form of the easily removable wing retainer.  Once it lifts out, the wings slide out, easy as that.  Time will tell how well it’ll hold up before it becomes necessary to permanently glue the wings in place.  For now, it works wonderfully.

Multiplex insists on providing their proprietary battery connector on the ESC for kits destined for the US.  It’s an excellent design, but rare here in the US and unavailable through my local hobby shop.  I swapped out the plug for a Deans Ultra Plug, allowing the use of one of my existing Deans-to-XT60 adapters for use with the Lectron Pro batteries.  As for the Multiplex connector, fear not.  It went to a good home.  My friend Rob Thomas, owner of Rise Up Hobbytown in Palm Desert, California uses them for electrical connections in his turbine powered models!

This photo shows what’s under the canopy when it’s first removed, including the Multiplex connector:

Completion

The easily removable wings are next and are just as easily secured with the plywood wing lock.  Step five instructs the assembler to install the propeller which, of course, is a serious no-no while setting up a new electric model!  Instead, I plugged in an Optima 6 receiver borrowed from another model; Suzanne sent a new receiver soon after.

Spotted another minor error at that time.

Some of the servo leads were incorrectly numbered, something I pointed out to Suzanne.  Another easy fix, but a really glaring error.  The ailerons are numbered 1 for left and 5 for right, both on the model and in the manual.  This is a nice touch if one wished to set up the ailerons on separate channels, but I went with a new Y-harness instead.

Out of the box, there was no way of obtaining the 30mm aileron deflection called for in the manual…and this is where I found another factory error when I went to relocate the pushrods!

Yet another barrel connector had unfinished threads, but this time, the factory jammed the set screw so tightly as to make loosening it nearly impossible. I removed the connector and discovered that it was barely tight enough to secure the pushrod.  Out came the tap once more.

Resetting the pushrods on the outer holes of the arms just did the trick, but now there was no way I was going to get the recommended 50mm of throw for 3D!  No dual rates for this baby, but I later found they really aren’t needed unless one is determined to fly 3D.  For sport and stunt flying, the throws are more than adequate.  Expo was initially set to the recommended 40 percent with the recommended throws of 30, 40 and 55mm for ailerons, elevator and rudder respectively.

From here, it was a simple matter of checking the fit of the battery on its ingenious removable board and installing the propeller.

Once in place, the tray is secured with a hook-and-loop strap:

The collet and spinner come as an assembly and it simply slides onto the motor shaft.  Tightening the collet with a 10mm socket and snapping the Elapor spinner cone in place complete the model…except for decals.

One needs a good two hours to apply them, almost more time than needed to assemble the model in the first place!  The manual uses monochrome photos to show the locations of the colored decals; the stripes would have been easier to apply if they were numbered.  A spray bottle of soapy water is a must when applying such large decals and care is required to squeegee out air bubbles.  Even so, the stripes continued to prove to be difficult since a couple of them lifted slightly while the water was drying.  That meant a wrinkle right on top of the empennage, but I figured it would be better than trying to slice it up to make it lay down.

Center of gravity of 110mm behind the LE of the wing with a battery in place was right on the money and all that remained was to get this model in the air!

Flying

A beautiful Sunday morning greeted the AcroMaster and I at the Coachella Valley Radio Control Club for its maiden flights.

Funny thing is, I have few if any butterflies in my gut when I maiden a fully aerobatic model since they’re very predictable (to me) as opposed to some scale subjects.  That day was no exception, so I got the AcroMaster ready to fly the moment I jumped out of the car.

Ground handling tests were first; the model needed some left rudder trim to get it tracking properly.  Once dialed in, it was real pleasure to taxi.

Getting airborne was nearly instantaneous; this is a very potent power system even on three cells.  Elevator response was touchy, but nothing a bit more expo didn’t cure later, at least to some degree.  In fact, it took off almost vertically when I pulled back on the stick.

Once trimmed, I took it easy in order to get the feel of things.  Halfway through the flight, I decided it was time for some fun.

Victory rolls were first and it had plenty of aileron authority, snapping back to neutral almost as well as if it were equipped with a gyro!  Inverted flight was a cinch. Tracking through a loop into an Immelmann turn was nearly perfect; the first attempt showed that a smidgen of aileron trim was needed.  Easy enough to do and my second attempt at a loop came off perfectly.  Knife edge was another matter.  I got the hang of it after the video shoot.  It needs very little rudder to maintain knife edge flight and I was feeding in too much.

When I tried landing, I found the AcroMaster really wants to fly!  It almost didn’t want to come down, even at near zero airspeed.  Back around for a second attempt;, this time, I flew it “into the ground” under minimum power for a near perfect landing with just a bit of bounce.

After I swapped in the second new Lectron Pro battery and tamed the elevator trim, large and small loops and a Cuban Eight came off without a hitch, although the elevator was still touchy.  Stall turns and stall recovery?  Oh, yes.  Lots of work went into this design and it showed.  It truly inspires confidence!  Again, the elevator was still touchy, but manageable meaning hammerheads were as easy to do as could be with nearly unlimited vertical flight on tap to climb to sufficient altitude. I didn’t need to do a second pass to land since I knew what to expect.  It dipped a wingtip across the surface of the runway; wider landing gear would eliminate that possibility and it’s something I would suggest the factory would consider.  The landing in the video was my best to date.

As seen in the video shot by George Muir, the historian of the Coachella Valley R/C Club, I was able to pull off a nice landing after plenty of stunts, but no knife edge yet.  No really good 3D either since the controls weren’t quite optimized for it; the video shows my very first attempts.  Longer control arms would be a tremendous help for someone looking to 3D this model.

Is this for a beginner?

Ease of assembly does not always equate ease of flight.  Even if one were to greatly reduce the control rates, the AcroMaster Pro does not self-right as a high-winged trainer would.  Mid-mounted wings with fully symmetrical airfoils and no dihedral equal a very responsive sport model for experienced pilots which goes exactly where it’s pointed.  There are plenty of trainers in the AcroMaster’s price range and below.

Gallery

The factory video shows just how capable this model is in the hands of expert pilots:

Here I am having a blast with the AcroMaster:

Tanner Curtis from Hitec wrings out his AcroMaster Pro, 3D and all in Yuma, Arizona:

Conclusion

I predicted the Multiplex AcroMaster Pro RR would be another winner from Multiplex and I’m pleased to report that it is.  It goes together quickly, quality components are installed at the factory and it is an absolute blast to fly.  The motor and ESC are rated for four cells, but the battery has a lot to do with CG on this model and it’ll likely be nose heavy should one attempt to fly on four cells.

Sure, I encountered some hardware issues totally unlike Multiplex, but nothing I couldn’t fix.  The end result is spectacular and worthy of a full two thumbs way, way up.  This model will be seeing a lot of stick time!

My sincerest thanks go to Suzanne Lepine, the peerless marketing manager of Hitec RCD who hooked me up with this model and who promised to pass along my few QC complaints.  Kenzier Lemmons at Common Sense RC has been one of my go-to contacts for batteries for years and I wish her the very best on her new endeavors!  George Muir of the Coachella Valley Radio Control Club is another longtime friend and contact who has cheerfully videotaped countless models for me over the years.

Nathan Maat mans the administrator’s desk here at RC Universe for the benefit of you, our worldwide audience.  Grab your own AcroMaster Pro and I’ll see you at the field!

Pluses and minuses

Pluses include:

  • World class flying characteristics
  • Easy, accurate, slop-free assembly
  • Top quality fit and finish
  • Top quality Hitec and Multiplex electronics
  • The ingenious wing and battery retainers make setup at the field a snap
  • Beefy motor and ESC wouldn’t be out of place on a larger model
  • Decals available separately so the end user can decide which color scheme to use or to use custom graphics

Minuses include:

  • Some hardware and servo labeling issues
  • Landing gear track could be wider
  • Stock servos and servo arms don’t allow for the recommended 3D throws
  • Batteries with Multiplex connectors don’t appear to be readily available in the US
Share.

About Author

2 Comments

  1. Xpress

    Hi Ralph,

    The AMP absolutely does posses all of the necessary ability to obtain 3D control throws out of the box, you can search my AMP youtube videos (under “XpressCS”) to see for yourself, though I’ll admit I have never used manual recommendations, I just crank the throws up to where I feel they are sufficient. Also I saw you mentioned the servo plugs being incorrectly numbered. I’m betting that you saw the ESC labeled as “4” and the rudder as “3”? This is because Multiplex radio systems default the throttle to channel 4 and the rudder to channel 3, as this model is designed to interface directly with their systems. Spektrum systems also use a non traditional channel layout so the servo numbers aren’t really relevant to anything that isn’t a Multiplex system. The decals also only took me roughly half an hour to get on just right, I guess this is where a practiced hand comes in handy.

    Good to see you’re enjoying the model, I’ve been flying the snot out of my model that Multiplex sent to me as a sample way back at the beginning of this year. I wound up adding 1/4oz of lead to the tail to push the CG back since moving the CG via the battery is not possible on this model. If you ever wander down to Yuma, come stop by the Yuma Aeromodelers club and I’d be happy to help you wring your AMP out.

    -Tanner Curtis

Leave A Reply