The comprehensive analysis: E-flite UMX Twin Otter BNF Basic with AS3X and SAFE Select

The model flight market offers a variety of options for hobby pilots, but especially aircraft in ultra-micro format are enjoying growing popularity. Today we devote ourselves to a special model from this segment: the compact double-decker of E-flite, which is characterized by its detailed and practical flight characteristics. This Twin Otter model in the Bind-N-Fly format combines scaling with modern flight technology and promises a unique flying experience for advanced pilots. In our detailed article we illuminate all aspects of this model - from technical data to customer experience to optimization possibilities.

Technical data at a glance

The ultra-light model aircraft comes with a series of impressive technical features that we have compiled here for you clearly:

The Twin Otters are particularly distinguished by their true-scale details such as LED navigation lights, simulated sheet metal impact edges on the control surfaces and opposite three-sheet propellers. With the included electronics and the pre-installed spectrum receiver, the model is ready for use almost immediately after unpacking.

Customer experiences and reviews

General user satisfaction

The ultra-light double-decker version enjoys an excellent reputation in the model flight community. Experienced pilots particularly praise the combination of scalable optics and stable flight properties. The feedback shows that the model meets its reputation as an ideal entry into the world of multi-engine aircraft.

Users report excellent flight performance even in light winds, with AS3X technology ensuring the necessary stability. The possibility of switching between the stabilizing SAFE mode for beginners and the more responsive AS3X mode for more experienced pilots is particularly appreciated.

Flight performance in practice test

In numerous practical tests, the compact double-engine trailer has convinced. The flight properties are described as good-natured but nevertheless agile. Pilots report an impressive climbing performance thanks to the powerful Brushless motors that provide powerful climbing flights even with standard 1S-500mAh batteries.

Depending on the battery used, flight times vary between 5-8 minutes in normal flight style. With larger 800mAh batteries, some users even report flights up to 10 minutes. The agility of the model is also preserved with heavier batteries, which speaks for the balanced construction.

Material quality and durability

The model made from EPS is described by users as amazingly robust. Despite the low weight of only 86 grams (without a battery), the Twin Otters also surpass smaller landing accidents. The installed components such as servos and motors prove to be reliable and durable in everyday use.

Criticism is isolated from the thin connecting points between hull and guide, which can be damaged in harder landings. Some experienced pilots therefore recommend a precautionary reinforcement of these areas with light adhesive tape.

Test results and performance data

Flight characteristics

In extensive tests, the ultra-light two-engineer shows impressive flight characteristics. The combination of high-decker design and AS3X stabilization technology ensures a stable flight image even in windy conditions. The model reacts precisely to control inputs and allows both relaxed cruises and more dynamic flight maneuvers.

The curve stability, which is supported by differential engine management, should be highlighted in particular. The engines can be controlled independently, allowing realistic taxi rides on the ground and precise curve flights.

Increased power and speed

With its two 7500KV brushless motors, the double-decker offers an impressive climbing performance. In the test, the model reached pitch angles of up to 45 degrees at full gas. The maximum speed is in the moderate range, which corresponds to the model of the Twin Otter Buschplane - this is more about agility and STOL capabilities (Short Take-Off and Landing) than about pure speed.

The starting and landing routes are correspondingly short, which gives the model its character as a bush-flyer. With a bit of counter-wind, it is possible to start less than one metre, which allows flying even in limited space.

Range and signal stability

The built-in spectrum receiver with DSMX technology ensures a reliable signal connection. In tests, stable control was achieved up to a distance of about 200 meters, which is more than sufficient for a model of this size class. The telemetry function also allows real-time monitoring of the battery voltage on compatible spectrum transmitters.

Transportability and everyday suitability

With its compact size (span width 574 mm), the E-flite UMX Twin Otter is ideal for transport. The model fits completely mounted in most middle transport bags and does not require disassembly for transport. The low weight makes the transport also pleasant.

The ultramicro size also allows flying in smaller rooms such as parks, sports grounds or even larger gardens. With the optional swimmers, the model can also be upgraded for water operations, which significantly expands the possibilities of use.

Spare parts supply and support

The spare part supply for the E-flite model is excellent. As part of the Horizon Hobby Group, the Twin Otters benefit from a well-developed sales network. All essential components such as propellers, motors, servos and electronics are available as spare parts.

The use of standardized components is particularly advantageous: The 1S batteries are compatible with many other UMX models, as are the servos and motors. This facilitates storage for pilots with multiple models and reduces operating costs in the long term.

Target group and entry barriers

The ultra-light double-decker is aimed primarily at advanced beginners to experienced pilots (level 2). Thanks to the SAFE Select technology, which can be activated on request, the model is also suitable for ambitious beginners with first experience.

The ideal target group includes:

• Advanced pilots looking for their first two-engine semi-trailers
• Model builder with preference for scalable bush aircraft
• Pilots with limited space for flying
• Model flyers looking for an uncomplicated, immediately ready-to-air model

Beginners should note that a compatible transmitter (at least 5 channels, spectrum DSMX/DSM2) and matching 1S-LiPo batteries and a corresponding charger must be purchased separately.

Assembly and commissioning

Construction and preparation

A great advantage of the BNF Basic model is the high degree of pre-production - it is mounted to 100% on the factory. After unpacking, only the transmitter must be bound with the receiver, a charged battery must be used, and the model is ready for flight.

The accompanying guide clearly leads through the binding process and contains helpful tips for adjusting the focus and the rudder deflections. The activation of the optional SAFE Select function is also explained in detail. The entire preparation until the first flight usually takes less than 30 minutes.

Instruction quality

The multilingual guide of the model is well structured and includes not only technical information but also helpful tips for flying. Especially valuable are the sections on the different flight modes (AS3X and SAFE Select) as well as the instructions for troubleshooting.

Beginners benefit from the detailed explanations for controlling a two-engine aircraft, while advanced pilots will find useful information to optimize flight performance.

Community support and exchange of experience

An active community has formed around the E-flite UMX Twin Otter. In numerous forums and social media owners exchange experiences, modifications and tips. This community support is particularly valuable for beginners and for technical questions.

Popular platforms for the exchange are RCGroups, various Facebook groups and YouTube channels with test reports and flight videos. There are also numerous instructions for modifications such as the installation of floats or LED lighting.

Alternative models compared

Compared models of other manufacturers

Those interested in the compact double decker should also take a look at these alternatives:

The FMS variant offers a significantly larger scale with more details, but is also heavier and requires more space for flying. The HobbyZone and Volantex alternatives are equipped with brush motors and are therefore often cheaper to purchase, but do not offer the same performance and scale loyalty.

Advantages and disadvantages over alternatives

Compared to the alternatives, the E-flite UMX Twin Otter offers the following advantages:

• Compact size with high accuracy
• High-quality brushless motors instead of the brush motors
• AS3X stabilisation for more precise flight behaviour
• Countless propellers as with the original

Disadvantages over some competitive models:

• Higher price than simple twin motor models with brush motors
• Lower size as scale models like the FMS variant
• Restricted load capacity for additional accessories

Value for money

With a price in the middle segment, the ultra-light double-engine trailer is positioned as a quality product for demanding pilots. The price-performance ratio can be rated as good to very good if you look at the high-quality equipment:

• Two brushless motors instead of cheaper brush motors
• Pre-installed spectrum receiver with AS3X and SAFE technology
• LED lighting and scalable details
• High pre-production (100% ready for flight)

It should be noted that additional costs for transmitters, batteries and chargers are incurred if they are not already available. The investment is particularly rewarding for pilots already in the spectrum ecosystem.

Tips, tricks and optimizations

Flight optimization

For optimal flight properties, experienced pilots recommend the following measures:

1. Priority optimization: The ideal center of gravity is about 30mm behind the front edge of the wing. A slight forward displacement (head load) improves stability while a rearward displacement (tail load) increases agility.

2. Rudder: For beginners it is recommended to reduce the outputs to about 70% of the maximum values. With increasing experience, the knockouts can be gradually increased.

3. Battery position: By displacing the battery by a few millimeters, the center of gravity can be finely adjusted. Mark the optimal position with a pin on the battery compartment.

4. Expo settings: An expo setting of 15-20% on the cross rudders and altar rudders ensures more sensitive control around the neutral position.

Performance increase

For more performance and longer flight times, the following modifications can be made:

1. Battery optimisation: The use of high-quality 1S-LiPos with 800mAh and high C rate (at least 30C) improves both performance and flight time.

2. Propeller optimization: Lightly modified propellers with a slightly more angle of attack can increase the tensile force, but are at the expense of the flight time.

3. Weight reduction: Unnecessary LED lighting can be clamped to save some grams of weight and extend the flight time.

4. Motor tuning: Some experienced pilots report on successes with easy "Timing Advance" of ESCs for more performance. However, this requires special programming devices and is at the expense of the engine life.

Extensions and accessories

The model can be extended with various accessories:

1. Floating: With the optional swimmers, a waterplane for the operation on ponds and small lakes is used from the bush flyer.

2. FPV extension: With ultra-light FPV cameras and transmitters (under 5g), the model can be equipped for first-person viewing flights. However, careful weight balance is required for this purpose.

3. Additional lighting: With SMD LEDs, the existing lighting can be extended, for example for landing lights or cabin lighting.

4. Pilot figures: Small, light pilot figures in the cockpit increase realism, but should be made from light foam for weight reasons.

Frequent questions and problems

Technical problems and solutions

Question: My model does not respond to the transmitter. What can I do?

Solution: First check whether the binding process has been done correctly. Turn the model off and back in and try to bind again. Make sure that the transmitter is set to DSMX and supports at least 5 channels.

Question: The engines run unevenly or one stops during the flight.

Solution: This can indicate a problem with the battery (too low capacity or C rate) or a loose connection. Check all connections and use only batteries with at least 30C discharge rate. A ESC reset could help with ongoing problems.

Question: The model strongly moves to one side in the flight.

Solution: First check whether both propellers are correctly mounted (against) and whether the engines run equally strong. Use the trim at the transmitter to compensate for slight deviations. In case of greater deviations, a mechanical deformation of the model could be present.

Flight problems and solutions

Question: How do I improve the gradient of my model?

Solution: For better climbing performance, it is recommended to use batteries with high C rate (min. 30C) and 800mAh capacity. Also the starting angle is important - start with slightly pulled uphill, but not too steep to avoid the flow crack.

Question: The model suddenly tilts in slow flights. How can I prevent that?

Solution: This behavior indicates a flow demolition. Activate the SAFE select function, which largely prevents a flow separation. Alternatively, you can fly at a slightly more speed and avoid more abrupt control movements.

Question: How can I extend the flight time?

Solution: For longer flight times, a calm flight style with moderate gas settings is recommended. Use 800mAh LiPos instead of the smaller variants. Also removing unneeded LEDs can take a few seconds flight time. Regular maintenance of the motors and bearings also contributes to more efficient operation.

Maintenance and care

Question: How do I clean the model correctly?

Solution: Clean Use the model only with a dry or slightly damp cloth. Avoid cleaning agents because they can attack the EPS material. Special attention should be given to the engines - regularly remove dust and lint from the shafts and bearings.

Question: After a landing in the grass a motor has failed. What can I do?

Solution: First check whether grass or other foreign bodies block the propeller or motor. Remove this carefully with a tweezer. If the engine continues to make problems, an exchange could be necessary. The engines are standardised and can be replaced individually.

Question: How do I correct the model?

Solution: Storage Ideally in a protective bag or box to avoid deformations. Take out the battery and store it separately (at about 3.8V for optimal service life). Protect the model from direct sunlight, as it can make the EPS material brittle with time.

Conclusion and recommendation for purchase

The E-flite UMX Twin Otter BNF Basic with AS3X and SAFE Select represents a successful combination of scale details and practical flight suitability in Ultramicro format. With its complete pre-installation of all necessary components, the powerful brushless motors and the advanced stabilization systems, it offers a convincing overall package for both advanced beginners and experienced pilots.

The STOL properties (Short Take-Off and Landing) which are according to the original airliner, as well as the possibility of expanding the model with optional floats for water operations are particularly noteworthy. The opposite three-sheet propellers and the LED lighting complete the authentic appearance.

The price-performance ratio is to be assessed as good in view of the high-quality equipment, and it should be noted that additional investments in transmitters, batteries and chargers may be required if they are not already available.

Who is this ultra-light two-engine aircraft suitable for? It is the ideal choice for pilots who:

• looking for an easy entry into the world of multi-engine aircraft
• have little space to fly and appreciate the advantages of Ultramicro format
• Place value on scalable appearance and realistic flight properties
• a robust, durable model for versatile applications

Beginners with first flight experiences benefit from the optional SAFE technology that facilitates the learning process while advanced pilots appreciate the precise flight characteristics with the AS3X system. With its versatile applications and active community support, this compact double decker is a recommended addition to any model aircraft collection.