TwinStar II

  • This review was first published in 2005 and the kit is still available.

Introduced to the world seven years ago in 1998, the TwinStar quickly became one of the most popular electric model aircraft of all time – and for good reason. It was relatively easy to build, could fly with standard radio gear, and the 7 - 8 cell 1700 - 2000mAh NiCD packs available at the time would allow a respectable duration of around 7 - 10 minutes. In the air the model was stable and easy to fly and could be assigned a variety of tasks: trainer, sports model, camera ship, battery cycler / test vehicle, thermal catcher or just an everyday hack. Not by accident has it been affectionately described as an aerial pick-up truck.

Electric powered it may have been, but the model could take a few knocks and if a serious mishap occurred then repairs could often be performed at the flying site with a little epoxy. As a result TwinStar boxes 'flew' off the model shop shelves and Multiplex were recognised as having started a foamie craze.

Many of today’s electric flyers will credit the TwinStar with having provided their first successful foray into electric flight and anyone who flew one back in the late ‘90s will always harbour a special affection for the model. No kit is perfect though and the TwinStar had its faults – a fact that made me rather intrigued to see how Multiplex had approached their latest version.

WHAT’S THE DIFFERENCE?
In order to fully appreciate the differences between the old and the new, the best place to start is the 2005 Multiplex catalogue which has many of the answers:

  • Smoother surface detail incorporating neater detail solutions
  • Improved aerodynamics
  • Improved durability – the model is now moulded in Elapor foam
  • Greater convenience of transport through separate wing panels
  • Faster construction as a result of no wooden parts
  • Easy-change screw fit motor installation for easy upgrades
  • Larger battery compartment

So, is the brochure right? Well, in a word, ‘yes’. Indeed the improvements become quickly apparent on close inspection, more so when construction starts.

As I said, the old TwinStar wasn’t perfect and by today’s standards there were some tricky bits to negotiate, particularly around the wing. The motors had to be glued into place, the wing spar fit was a little agricultural in nature, and the wing bolt mounting plate usually needed strengthening to avoid an unexpected in-flight separation! Still, that was seven years ago and recent offerings from Multiplex have come a long way. Take the EasyStar for example, a beautifully engineered model that could well have provided the impetus for the Multiplex design team to reverse engineer the Twin Star and bring the legendary electric hack up to date.

QUICK BUILD
The first and most obvious difference between TS-I and -II is that the new version is moulded from Elapor (EPO) foam and not the more brittle EPS variety of the original. Having proven its worth as a robust yet flexible material that’s able to withstand knocks (not to mention a fairly decent crash) Multiplex make all their foam ‘planes from Elapor nowadays. With just two fuselage halves, two wing panels, tail feathers, motors, props and assorted hardware, the TS-II’s part count is modest. There’s a modicum of complication in that the wing panels are designed to be separated for ease of transportation. However, since this is not a particularly large aeroplane, it’s just as likely to remain fully assembled at all times.

Like the EasyStar, the wing panels are supported by a stiff, tubular, carbon spar. Wing assembly entails dropping a couple of mini servos in place and connecting up the ailerons. Motor and servo wires are then hidden beneath an Elapor fillet which is shaped to leave a tunnel for the wing spar.

In practise a little foam cutting may be needed to ensure the wires have sufficient room and the fillet sits flush with the wing. It’s great to see that a lot more thought has gone into the wing assembly. One improvement that can be instantly appreciated is the fact that the motors are now screwed into purpose-designed mounts. On the original model the motor can was glued directly to the nacelle, making replacement almost impossible without inflicting some minor structural damage.

For the review I chose to use the standard 6V 400-size motors supplied, though do check my later comments about the motor upgrade option before making your final decision. Two bolt-down plastic clamps are supplied to hold the wing panels in place, the wing bolt mounts being moulded into the fuselage; once again, as far as I’m concerned, this is a significant improvement on the original. Fuselage construction is equally quick with pre-moulded servo apertures and appropriately routed pushrod cable ducts making light work of the radio installation. Drop in a pair of mini servos, feed the snakes along the ducts, connect it all up and the job’s done.

FINISHING TOUCHES
Despite a kiddie-coloured sticker sheet being supplied the predominantly white model can still look rather bland and, in haste, I decided to spray my wings and tail feathers in ‘Easy Star blue’ so as to add a little colour. In hindsight, however, I wish I’d used a scheme that’s more representative of a full-size aeroplane – US Coast Guard colours, perhaps? You’ll do better with yours I’m sure.

Another neat little innovation is a fuselage-located PCB that’s designed as a junction-box for connecting the receiver and speed controller to the wing-mounted motor and servo wires. It’s a simple device which has worked well for me, although I do have some misgivings as to how robust the unit may prove in the long term. Continued plugging and unplugging may find a weakness here; on the other hand, it may not! Incidentally, some clever thinking has gone into the design of this item as, whichever way around the motor connectors are plugged, it’s impossible to reverse the polarity.

Plenty of room has been reserved for the battery pack, be it a 7 - 10 cell NiCad, NiMH, or 2s3p Li-Po, whilst a cooling vent in the nose and an outlet behind the wing allow air to pass over the battery and controller.

Incidentally, for the beginners amongst us, the instruction manual is in the usual Multiplex style, i.e. multilingual text sections with a set of diagrams covering the major stages. I’ve always thought that Multiplex could perhaps try a little harder than they do when it comes to instructions and whilst the text in this instance does a good job of describing the build sequence, paging back and forth when referring to a diagram is a nuisance. In fairness, however, the Twin Star is such an uncomplicated build that a half competent modeller could probably construct it from the diagrams alone, though clearly, this won’t console a beginner seeking reassurance along the way.

MEMORIES, MEMORIES...
In flight the Twin Star II is much like the TwinStar I... now there’s a surprise! A little quieter, perhaps smoother, but certainly the TwinStar’s original flight characteristics are evident.

Climb-out is positive and turns are easy although aileron differential is essential with this model; I dialled in 50%. The instruction manual details this in the control throw section so do make sure you program more ‘up’ than ‘down’ to avoid needing rudder in the turns. While we’re on the subject, beginners should note that it’s essential to have a six-channel receiver for this model, as the aileron servos need to be connected into a separate Rx channel in order to achieve the aforementioned differential. Of course, a computer radio will also allow a little rudder to be mixed in with ailerons if so desired.

Elevator has always been a powerful control on the TwinStar and it remains so. I like this as I tend to fly the model very low and usually need a means of escape when things don’t go quite to plan. Incidentally, she’ll still perform a great touch ‘n’ go when the grass is wet – a stunt that always surprises onlookers.

Whilst this model is quite capable of handling a breeze, you won’t be surprised to hear that it’s far more pleasant in a windless sky and, with the correct C of G, is quite difficult to stall. Basic aerobatics such as loops, rolls and bunts are easily performed on the stock powertrain, though you should ensure the battery is securely located and won’t move around during such antics. This aside, vertical performance on the standard 400 motors is a little lacking and, as a result, you’ll not find stall turns particularly successful.

As ever the twin electric motors sound great in action but seem somehow quieter than the identical set-up of the original model. Perhaps Elapor has superior sound absorbing qualities? What’s more there’s a certain refinement of the TS-II’s flying characteristics that the first version lacked; it’s a trait that’s difficult to articulate but perhaps the revised aerodynamics have something to do with it – turns seem smoother and with taps open and amps flowing she displays a fair turn of speed.

PACK IT UP
Okay, let’s talk battery packs. For the first flight I though it appropriate to use my vintage 7-cell 1700mAh Sanyo job that flew my original TwinStar some five years ago. This, incidentally, was like meeting an old friend, and I don’t mind telling you I got all emotional and misty-eyed about it. Now, in the old days the pack provided about 7 - 8 minutes of frenetic flying and, guess what? That’s just what it did again! Same motors, same pack – fair enough.

Of course, seven minutes of electric flight was top-notch five years ago but no modern self-respecting electric flyer would be satisfied with such a paltry flight time now, so I looked around my workshop for something a little better. I didn’t really want to splash out on a new pack for the model when I had so many others lying around, indeed it was this very issue that reminded me of the TwinStar’s incredible cell versatility; it’ll fly on whatever it’s given and if, like me, you’ve collected a shelf full of packs over the years, this is very handy. My eyes quickly settled on my FlightPower 3s2p 5000mAh Li-Po that regularly sees use in my RCM Pelikan Tukano. Hmm, 11.1V and 5000mAh, eh? That would give the little 400s something to think about and produce flight times close to 30 minutes, maybe longer with careful throttle management – a whole flying session in one pack! That sounded fine except the 6V motors would eventually feel the strain from 11.1V and the risk of burnt-out cans would be high. Should I upgrade them to 7.2V? It’s an upgrade that I haven’t yet made but probably will soon. For now I’ve tried to fly carefully, limiting throttle as much as possible. Thus far the motors have thanked me by staying alive.

GOLD STAR
So there you have it, a sensible revision of what is now widely regarded as something of an aeromodelling classic. This upgrade is evolutionary rather than revolutionary but then why get radical with such a well-proven design? Compared to the original the new TwinStar is easier / faster to build and more robust. In the air it’s still great fun to fly whilst remaining an extremely versatile platform.

Years ago I took my first TwinStar to an electric fly-in and got a few smirks from the assembled electro ‘experts’ present. One even chided me for bringing it along. I sold it shortly after and instantly regretted my haste. I’ve since lost count of the number of times I wish I’d had my dependable old TwinStar in the hangar. Be it for training, aerial photography or just to run-in a new NiCD battery pack my TwinStar-less existence has made me realise what a great job Multiplex did with the original design.

2011 UPDATE
The Twinstar still sells and remains a popular model. The brushed motors in the review model never burnt out and remained with the airframe until it was retired and I think it flies fine using the brushed motors, especially for relative beginners or those happy with a more modest (yet still enjoyable) performance. Ironically some builders have reported problems sourcing brushed ESCs so the there may be no choice but to follow the brushless upgrade route. 

DATAFILE
Name: TwinStar II
Model type: Twin electric sportster
Street price: around £62 (April 2011)
Wingspan: 1420mm (56'')
Fuselage length: 1085mm (43'')
Wing area: 43dM2 (4.63sq. ft.)
All-up weight: 1500g (53oz)
Wing loading: 11.5oz / sq. ft.
Rec’d motors: 2 x 6V 400-size brushed (supplied)
Flight packs used: Sanyo 7-cell 1700mAh or 3s Li-Po
Control functions: Aileron, elevator, rudder, throttle via ESC

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