Written by Dave Lockhart Sports & Aerobatics Technical As seen in the Fall 2018 issue of Park Pilot.
>> “3D is for the new generation of fliers.” “Gyros are too expensive and too complicated to use.” These are two statements that I have heard countless times but are less accurate now than even a few years ago. In short, the newest generation of gyros allows pilots to confidently fly a broader range of aircraft and to more easily expand their inventory of maneuvers. The newest gyros are increasingly smaller, lighter, less expensive, easier to program, and capable of far more than stabilization in one or more axis. Not only can the degree of stabilization be adjusted for multiple settings (selectable in flight from the transmitter), but control surface deflection, dual rates, exponential, and flight trim can be programmed as well.
The Aura 8 is compatible with a range of radio brands, and the setup can easily be optimized for different aircraft using a PC interface. Not only can the gyro behavior be changed, but throws, dual rates, and exponential can be changed as well. This potentially provides programming options not available in some transmitters. Photo provided by Flex Innovations/Quique Somenzini.
Flex Innovations (flexinnovations.com) and Horizon Hobby (horizonhobby.com) are two companies that produce aircraft that include preprogrammed gyros and also offer standalone gyros that can be added to virtually any aircraft. These new products make it easier than ever for beginner pilots—and traditional aerobatics pilots—to step into 3D flying. Smaller aircraft, that are often more sensitive and “twitchy,” tend to feel like larger, more locked-in aircraft. Short, coupled aircraft, such as Cubs, have greatly improved handling on the ground. Ground loops are a thing of the past, and bouncing when landing is reduced. Even using “stick and rudder” for the smoothest turns becomes easier for the pilot with an onboard gyro system.
The interior of a Flex Innovations Mamba 10 shows a clean equipment layout with the included preprogrammed Aura 8 Advanced Flight Control System in the aft equipment bay. Flex Innovations/Somenzini photo.
Many full-scale aircraft are notorious for being challenging to fly when they are scaled down to model size. Multiengine airplanes no longer have yaw trim changes because of variable performance between engines. High-performance warbirds are less likely to experience tip stalls at low speeds or during high-G aerobatics. Specific to aerobatic aircraft, there are many benefits when using gyro systems. Aircraft can be set up aggressively with an aft CG (center of gravity) and extreme control throws to allow rapid changes in direction and spectacular tumbling. With the stability of the gyro, however, recovery from tumbles is much more predictable and consistent. Control sensitivity for normal flight is not twitchy. Another benefit of gyro systems is that they can reduce bad flight tendencies because of less-than-ideal construction, repairs, and setup. Although all aircraft are ideally straight, warp free, and do not flex in flight, the reality is that not all aircraft are perfect when they are new, and certainly not after some wear and tear from flying.
With the included Aura 8, simple 3D maneuvers, such as harriers and hovers, are well within the skillset of intermediate pilots and those new to 3D. Flex Innovations/Somenzini photo.
Small warps that can cause trim changes with a change in airspeed are often countered by a good gyro setup. A heavy wingtip that tends to drop upon landing will be less likely to do so when a gyro is used. Of course, the better answer is to add a small amount of weight to the light wingtip to achieve good lateral balance. There are few, if any, downsides to a well set up gyro system, but care must be taken when using high gain settings. Slower servos might not be able to keep pace with rapid inputs from a gyro using high gain settings, and control oscillations can occur in the air (typically rapidly “galloping” in pitch). Slop in servo gears or linkages can result in increased control surface oscillations on the ground or in the air. Flying at high speeds with high gain settings requires fast servos and linkages with no slop.
An E-flite Clipped Wing Cub 1.2-meter BNF Basic uses a Spektrum AR636 receiver with built-in AS3X stabilization that is pretuned for several flight modes. It’s suitable for beginner to mild 3D. Photo by Jennifer Alderman.
Although gyro systems do not specifically add maneuvers to a pilot’s inventory of stunts, they make it easier to perform many maneuvers. For example, a simple harrier pass involves balancing the amount of up-elevator and the proper throttle setting to achieve a nose-high attitude at slow speed. Ailerons typically must be used to combat wing rock, and rudder is required to maintain a straight line (and help with wing rock to an extent). With gyro systems onboard, wing rock is reduced, and nose wander to the left and right is minimized. How effectively the gyro levels the wing and keeps the nose straight is dependent upon the gyro settings, the speed of the servos, and an aircraft’s design. With a reduced pilot workload to keep the wing level and the nose on course, it is much easier to focus on modulating the elevator and throttle to complete a harrier pass.
Even the included diminutive receiver in the 36-gram E-flite Yak 54 3D has AS3X stabilization, which greatly increases the amount of wind and turbulence that this micro flier can handle. Photo by Dave Lockhart.
Specific to Horizon Hobby, many of the Spektrum receivers have built-in gyros. When included with Horizon Hobby-brand aircraft, they generally have multiple preprogrammed flight modes. With most aircraft, the higher stability modes allow intermediate pilots to safely fly aircraft traditionally flown by more experienced pilots. Aerobatic modes allow unrestricted aerobatics while providing stability in turbulent wind.
Programming AS3X receivers can be completed with mobile devices (Android or iOS) or PCs. Available programming includes gyro behavior, as well as control surface deflection, rates, and exponential settings. Photo provided by Horizon Hobby/Dan Landis.
Flex Innovations has a growing line of aerobatic models that are designed from the ground up to be flown with the Aura 8 Advanced Flight Control System. The Mamba 10 and Extra 300 are slightly larger (approximately 3 pounds) than most aerobatic park flyers (and heavier than the Park Pilot Program weight limit of 2 pounds), but they are capable of being flown comfortably in small spaces. The aircraft are extremely agile but retain good stability with the Aura 8 onboard. Without a doubt, the capability of the newest gyro systems can add substantially to the experience of a broad range of aircraft and pilots. -Dave Lockhart [email protected]
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