Multiplex Twin Star
Introduction
There must have been quite literally millions of Twin Stars sold, because at one time you could not go to the flying field without one being there! I wonder if Multiplex realised just how successful the Twin Star was going to be. I have flown other modeller’s Twin Star in the past and so I had a reasonable idea how well they flew. I have been looking at buying one for some time. Last year when I was at Weston Park International Model Air Show, Inwood Models had a deal on the Twin Star. At that time I could not justify buying another model. I have sold off some of my models that were no longer in favour. Over the winter I was going to have a look at one of my local model shows to see what deals, if any were on the Twin Star. As it turned out, I had to work over the weekend of the show. So on the Monday I made a telephone call to Inwood Models and had arranged a Twin Star deal. Two days later the parcel was delivered.
The Model
Multiplex description of this model is, "the electric model with that
certain "something". The Twin Star is a two-motor semi-scale model
aircraft consisting of ready-made components, which just plug together requiring
only a few glued joints. The Twin Star is extremely stable, easy to control and
so manoeuvrable that it can be flown safely from any medium sized field. The
model is designed to be hand launched, with its two motors the Twin Star has
plenty of power in reserve for aerobatics and that livens up flying no
end". I have to agree with them on the performance, as it surprised me.
What do you get for your money?
Clear assembly instructions in German, English, French, Italian and Spanish.
Moulded Styrofoam fuselage, two wing panel,
die-cut
plywood panels, decal sheet, small parts and control linkage hardware. Included
in the kit is the power set which consists of two Permax 400 Electric motors,
125 x 10 mm Propellers and power system cable set.
Building
The building instructions have an important note at the start that informs you not to use solvent-based adhesives. Solvent-based adhesives will melt and destroy a large volume of the foam. In particular, avoid instant or cyano-acrylate glue. It is recommended that you use solvent-free adhesives, such as 5-minute epoxy, or white glue. For the majority of the gluing I use 5-minute epoxy as it reduces the build time, compared to white glue. Building the model starts with 1) The Canopy. No problem here, just a plywood plate and two hooks screw into balsa block. 2) The Elevator is attached to the Tailplane using four hinges and the horn is also secured with 5-minute epoxy. 3) Fin and Rudder the same as Tailplane, only using two hinges. 4) Gluing the tail panels to the fuselage. I have left out some of the more mundane bits. Particular care is needed at this stage, as proper alignment is crucial to the model’s flying characteristics. The tailplane and fin are glued to the Fuselage. Whilst the glue is still soft carefully align the Tailplane and Fin relative to the wing saddle also ensuring the Fin is exactly at right angles to the Tailplane. 5) Installing the wing retainer plates in the fuselage. There is a Product Maintenance sheet for the front wing mount. It originally featured a threaded hole for the wing retaining screw, which was cut using a thread-cutting screw. This has now been up-dated and replaced with a 4mm captive nut. The rear wing retainer plate is still threaded using the thread-cutting screw. Once I had threaded the plate, as per the instructions, I applied some thin cyano to the hole and when it had set I rethreaded the hole. The result is a good, clean, tough thread.
Wings
I was a little disappointed to find the cardboard packing inserts had damaged
the wing around the motor mounts. I think the packing needs modifying to prevent
this happening. 6) Joining the Wings, I have made a modification to my wings.
Having spoken to model flyers with a Twin Star, it would appear that if you are
a bit rough with it in the air the wing starts to crack around the engine mount.
One modeler had over-come this by fitting a 6mm hollow carbon fiber rod to the
wing. I have adopted this idea and, with the use of a soldering iron, I melted a
groove in the bottom of the wings between the wing spares. I practiced on some
strap foam first, by holding a still ruler on the foam and running the iron down
it. The speed at which you move the iron determines the size of the groove. The
thought of melting my new wings was a bit off putting, but it went well and I
was
very pleased with the result. The carbon fiber rod was then glued in using
5-minute epoxy. The wings are joined with 20mm of packing under each tip to give
you the correct angle of dihedral. 7) Deploying the power system cables,
per-made no problem here.
I did not stick to the instructions here and jumped a couple of steps to 11) deploying the aileron servo cables. I did this because I felt that it would better to get the wing spars installed. This was the next step as soon as I could, as the wings appeared a bit bendy. If you follow the instructions it goes on to install the motors and ailerons before the wing spars! 12) Installing the aileron servos. The servos can be covered with heat-shrink and then glued in with 5-minute epoxy. Covering them with heat-shrink enables them to be removed. I use two-way servo tape, which I have never had a problem with. There are only a couple of steps to finish the Twin Star. 13) Trimming the wing fairing. 15) Attaching the wing to the fuselage. 16) Installing the receiver and servos, and so on. With the model finished, control surfaces travel setup, balanced, you have a multi-colored décor sheet to decorate your model. I have seen a number of Twin Stars decorated in many ways. I have used the décor sheet supplied.
Installing the RC system
I use a couple of old Hi Tec servos that I had for the Elevator and Rudder control. There is room in the fuselage to use a standard receiver. The 35amp speed control was installed and the flight battery.
I set the control surface travels up as per the instructions.
Balancing
With the model fully rigged I balanced the model, as per the instructions, by
moving the flight battery. Once I had the Centre of Gravity correct I marked the
position of the battery. The instructions go on to say that if you intend to
roll the model, or try inverted flight, they recommend that you secure the
flight pack so that it cannot fall out. This is done by pushing a piece of scrap
foam between the battery and the front wing retaining plate, but take care not
to obstruct the circulation of cooling air too much.
Test flight
Its first flight took place at Filey on the Sunday of the MAA Flying Holiday, it was a lovely sunny day with no wind and a perfect day for a test flight. With the model assembled, a range check was completed with and without the motor running, all was fine. With the help of another MAA member the model was checked once more for control, balance and launch into what wind there was. The model climbed away just perfect. I no how many times you have heard this, but I did not have to trim the model at all. I gained height so that I could stop the motors, the glide appeared slightly fast to me. I gained height once again, stopped the motors, put the model into a dive and with the elevator released to neutral it pulled out straight away. I prefer my models to stay in the dive a little longer. The still was explored, and there was no problem as it just nodded. The responses to the controls are fine set up as the instructions suggest. I tried some inverted flight and found that I had to put more down stick in than I liked to be able to hold the model level. With the battery only having had a couple of motor runs, it was time to do some low passes for the camera. I flew the model around until the BEC cut in. The landing was not a problem, even without the ability to use the motors. Before the second flight I decided to move the centre of gravity back a bit. So I put the flight battery back as far as they would go in the battery box with the fuselage. I added some down trim and I also enabled the Ailerons/Rudder coupling. On the second flight the model climbed away to steep and I needed to put in down trim to maintain level flight. I tried the dive test again. The recovery was not as sharp and the inverted flight was improved.
This just goes to show you we can all get it wrong some times! On my third
flight I got caught out by the BEC on the speed controller and did not have
enough height/power to get back to the top of the slope. The result, my Twin
Star being flown in to the slope in a desperate attempt to get back to the top
of the slope. The front wing mounting was broken and the rear put out along with
some Styrofoam. It was easy to fix with some 5-minute epoxy. Over the two weeks
of the holiday I had ample opportunity to fly the Twin Star. It is extremely
stable, easy to control, and yet very manoeuvrable. With its twin motors, it has
plenty of power for aerobatics and touch and go landings, even with only a
seven-cell flight battery!
Conclusion
The Multiplex Twin Star is a very easy model to build and fly. It is responsive enough not to be boring, but on the other hand it will almost fly itself. The wings appear to be a little on the flimsy side for my liking. The quality of the kit is very good and you are almost guaranteed this with Multiplex. Having now built and flown a Twin Star, I know why so many have been sold and wish I had purchased one a long time ago!
Specifications
Information
Name: Twin Star
Manufacturer: Multiplex
Price: £49.95
Inwood’s Deal: £117.99 includes Twin Star, Two Topaz Micro Servo 1-TOP1000 Ball Raced Output, Jeti Model’s jes 350 35A Speed Controller and an Overlander’s 8.4v 2100MAH battery pack.
Model Information
R/C Function
Specification
Dislikes
Likes