Tensor 4D
The Tensor 4D — the indoor 4D foam aerobatic airframe that brought reverse-thrust hovering and unlimited handling to small spaces.
About
The Tensor 4D belongs to the "4D" category of indoor aerobatic foamies — a specialized niche where extreme-low-wing-loading airframes paired with reverse-thrust-capable brushless motors can perform maneuvers no conventional 3D aircraft can. The defining feature of 4D flying is reverse thrust: a brushless motor that can spin in either direction, paired with a propeller that produces thrust in either direction, allowing the airframe to back up in flight, hover with negative thrust, and execute "torque rolls in reverse" that simply don't exist in conventional 3D.
The Tensor 4D was one of the original purpose-designed 4D airframes, with a flat-foam construction, oversize control surfaces, and a powerplant arrangement specifically chosen to enable reverse-thrust maneuvers. The result is an airframe that has expanded the unlimited aerobatic vocabulary in directions that are mostly impractical for any larger or heavier aircraft.
The bigger picture is the 4D category itself. Indoor 4D foamies — whether the Tensor 4D, Crack Yak, or any of dozens of similar designs from RC manufacturers and homebuilt designers — have become one of the most technically demanding niches in modern RC, requiring purpose-designed airframes, brushless motors, ESCs, and propellers that simply did not exist in the hobby a generation ago.
In the simulator
The most demanding aerobatic mount in this pack. Reverse-thrust capability and the kind of stick discipline 4D flying demands. Use it for the unlimited-4D vocabulary: backwards flight, reverse hover, torque rolls in both directions.
