Predictions about the model aircraft industry are hard to make. Imagine 30 years ago standing around the local model club telling all and sundry about the vision you had the night before of ultra-powerful electric motors, powered by batteries that pump out more energy than a tank of glow fuel and were fitted to superbly moulded foam models!
Yes there would have been a few laughs, some gentle ribbing, then everyone would have gone back to flying their home built balsa beauties with the stock .40 or .60 glow motor up front.
Yet today that’s exactly what we have. The Multiplex Extra 300S is just such an example of the wondrous foam models we now have on offer. Boasting a wing span of 1.2 metre and with the fuselage a little over 1 metre and made of the super tough Zacki Elapor foam, the Extra comes with a Permax BL-0 3720-630 motor and Multiplex 50 Amp speed controller, and servos are preinstalled as well. The quality of the finish is first rate, something I’m used to finding with Multiplex models.
So Let’s Assemble Then Fly!
This is a very quick build model so there really isn’t much to write about. The fuselage comes out of the box with everything pretty much done. The undercarriage is bolted on, as is the horizontal and vertical stabiliser and control surfaces. The servos already have EZ connectors on the control horns so it’s a few seconds work to connect each servo to its control surface. The only thing I was disappointed about was the lack of a pilot in that lovely big cockpit.
A scalelike three blade propeller is supplied along with a spinner that looks like aluminium but is actually plastic. I always balance my props and so after a quick run on the balancer it was installed on the motor.
The wings are next to being brought into the spotlight. These also have the servos installed, so in a jiffy the control rods were connected. As an aside, when I use EZ connectors I always put a spot of Loctite on the screw, it only takes seconds but it means nothing will come loose. The wings have a carbon fibre rod that slides easily into the internal wing channel and the panels are then screwed onto the fuselage with self-tapping screws. I used the Multiplex Smart SX transmitter and a matching Multiplex RX 5 M link receiver. This mounts in the front hatch behind the battery, with all leads being routed up the fuselage. Okay, we’re all ready for the test flight.
I set the controls on low rate as I had a feeling with such large control surfaces the Extra would be a handful for my old thumbs. A 14.8 volt 3300 mAh 4s battery was plugged in and with the controls given one final check to make sure they worked in the correct sense, I throttled up.
The model has small wheels and spats, though this didn’t seem to be a problem on the far from smooth surface I was flying from. The three-blade prop generates a decent swing to the left as power is applied but once it was tracking straight a touch of up saw it leap into the sky.
On a 14.8 volt battery the model is very fast. Trim was spot on but I had to reduce throttle in order to catch my breath as even with reduced throws I found myself over controlling a touch.
Once I had my composure back I was delighted with the performance. Like all aerobatic aircraft of its type, the Extra just stays where it’s pointed and at whatever bank angle you leave it at. It needs to be flown all the time and that’s the attraction of such a model. No down was needed for inverted flight, whilst the roll rate was awesome and loops were as big or as small as I wanted. The stall is reasonably abrupt, but does occur at quite a slow speed, though there is a wing drop to watch for.
After six minutes it was time to land. It isn’t a model to be floated onto the strip, but rather needs a touch of speed to keep airflow over the control surfaces. My first touchdown was far from elegant but subsequent attempts have seen this improve as I have become used to the speed & attitude combination needed to keep it tidy.
So there we have it. Another winner from Multiplex. It’s certainly not a beginner’s model, but would make an excellent aerobatic trainer to teach the discipline of precision aerobatic flight.