Great Planes Twinstar Electric Twin Trainer

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Introduction

For years, Hobbico was offering a glow twin sport plane known as the TwinStar. This airframe was known to be one of the easiest planes in the twin realm to setup and succeed with separate throttle servos and fuel tanks for each engine. While the glow version does not seem to be available anymore from Hobbico, the Electric version of the TwinStar which has recently been introduced seems to be a perfectly updated replacement of the original glow version. Provided in a slightly smaller form factor (56″ vs 47.5″ wingspan), the new TwinStar seems to have all of the factors which made the original such a success with twin enthusiasts. The TwinStar is a sport airframe meaning it has been optimized for flight characteristics over scale looks. The engines are positioned closer to the fuselage for a claimed increase in stability and it arrives with fixed landing gear and a steerable nose gear much like the original. With a low part count and ARF form factor, it will not take long to get this new TwinStar ready for flight so lets dive right in and see what it has to offer.

Features

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  • Magnetically attached hatch with easy access to flight battery.
  • Dual aileron servos for differential and flaperon mixing options.
  • Quality balsa and ply construction.
  • Tricycle landing gear with steerable nose wheel.

Specifications

  • Wingspan: 47.5 in
  • Wing Area: 392 in²
  • Weight: 4.0 – 4.25 lb
  • Wing Loading: 24-25 oz/ft²
  • Length: 42.5 in

What you Get

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The shipping box is colorfully decorated and is well packaged providing sufficient protection against damage from shipment. The low part count nature of the TwinStar ARF can be easily seen with all the parts laid out on the building table. The first thing that you will probably check out is the magnetic hatch which is easy to remove and is pretty solidly held on the fuselage once attached via the magnets.

The covering on the TwinStar is pretty good. I did not have to do any touchups besides running a low temp heat gun over some troubled areas. The fixed landing gear features a spring on the nose gear. One of the things I am not too crazy about this airframe is the use of stickers to detail the fuselage. However, once applied you quickly get used to the looks and rarely give it a second thought.

The wings are provided in two pieces and are meant to be glued together and attached to the fuselage with a tab in the front and two bolts in the back. The engine nacelle frames are provided as built up pieces which fit perfectly on the slots in the wings. The nacelles themselves are thin plastic along with the nose cone. The nacelles are pretty solid once attached to the wings but care has to be given to the nose cone which is rather fragile and can be damaged quite easily by mishandling the airframe.

For this review, the Futaba S3115 servos will be utilized along with the recommended electronics from Hobbico, namely the RimFire .10 motors along with 25A ESC. The flight pack is from FlightPower and is a 3S3800mAh.

Assembly

Assembly of the airframe starts with the installation of the aileron servos. This is a pretty straight forward process. It is easier to bolt the landing gear after the wing has been prepared but shown here for reference as to the drop in nature of the assembly. The nacelle frames are glued in to the wings in preparation for the installation of the motor and ESCs.

The RimFire .10 motors bolt right on the nacelle frames and there is ample space in the frames to place the ESCs. The wings are then glued together and the servo and ESC extensions are routed through the wings. A battery Y-harness is used for the ESC power connectors along with a separate servo Y-harness for the throttle leads to the ESCs.

The plastic nacelles are then attached to the fuselage and the propeller and spinner fitted to the motors. The provided spinners are white in the product marketing brochures but the ones supplied were red which I think looks better on the TwinStar.

The steerable nose gear is easily attached to the fuselage using the provided parts and the steering arm connected to the single rudder servo that is placed in the fuselage.

The nose cone is trimmed slightly to allow it to fit on the nose while clearing the nose gear. The manual recommends that you tape on the nose cone instead of the standard screws which are used to attach fiberglass cowls and I have to say I agree with this recommendation as you will undoubtedly have to replace this at one point if you are not careful in handling the airframe.   Two elevator and rudder servos are installed and connected in the fuselage. The spacing provided was a perfect fit for the recommended servos.

The tail section is glued on and the linkages made to the control rods and the TwinStar is almost ready for flight.

There is ample space in the nose of the fuselage to install the flight pack. I did find that I had to route the ESC lead through the hole in the rear of the removable hatch to relieve it of pressure due to the length of the leads pushing up against the hatch itself.

Flight Report

The first thing I have to say about the TwinStar is that the twin RimFire .10 motors really pull this airframe IMG_2780 (1)around with authority. So much that I found myself limiting the use of full throttle to vertical lines and high speed passes only. When lined up for take off, you have to ease the power in to avoid the TwinStar really darting off and when in the air, taking the TwinStar to full power provides for very good vertical performance and the power to really pull it out of sticky situations if needed.

The tricycle landing gear and steerable nose gear provide good ground handling but the main gear can cause unwanted bumps on landing as they do not have any inherent shock absorbing capability. Getting the TwinStar ready for flight is as easy as installing the main flight battery with the provided hook and look straps and attaching the magnetically sealed hatch. It did not take more than a single circuit around the field to get the TwinStar trimmed out and flying level on the maiden flight with minimal trim applied on the ailerons and elevator.

Once the TwinStar was trimmed and flying level, I rolled it over to perform a few inverted passes and was pleased to find that the TwinStar needed nearly no correction on the elevator to fly level. This could indicate a tail heavyIMG_2805 configuration but I did not really feel that it was tail heavy as it flew equally well upright so I left it like that. With no correction required, I was getting braver and bringing the TwinStar in lower and lower while inverted over the runway with each successive pass. Regarding its aerobatic capability, the TwinStar is a sport plane and can perform the variety of maneuvers that you would expect from such an airframe. Knife edge flight is possible and required minimal correction as well which was very pleasing. The power available from the twin RimFire .10 motors made large loops possible.

The flight times that I was achieving with the recommended setup were easily approaching the 10 minute mark with limited use of full throttle which made flying the TwinStar all that more fun. The TwinStar also provides a very good glide ratio and is very easy to bring in for final approach under no throttle. As mentioned before, you have to watch the final touch down to avoid a bounce from the wire mains.

After a few flights, I was curious to see if the TwinStar could in fact fly with a single engine so I disconnected one of the motors and rolled it out to the runway. I would have to say that the flight experience with a single engine is not very good or pleasing however the TwinStar was controllable as I was able to take off, fly a few circuits and land with no issues. It is comforting to know that you will be able to save the airframe should one of the motors or ESCs fail in flight.

Summary

After having the chance to build and fly the redesigned electric version of the TwinStar, I have to say that I was pleased with both its ease of assembly and good nature of its flight characteristics. I do wish that the designers had provided the nose cone in fiberglass instead of plastic and that the fuselage had some other option than stickers to give the final looks of the airframe but this is not a big worry overall. In the air, the TwinStar provided on its promise of sport performance and the power provided from the recommended gear was very nice. Combined with the long flight times that I was able to achieve with the 3S3800mAh battery, I would have to say that the TwinStar should be a success for Great Planes once again and easily please any sport plane enthusiast.

Gear Used

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