Aerobatic ARFs-Editors' Top 10 Picks : Pump Up the Adrenaline!

Model Airplane News, Jun 2003

AEROBATIC ARFs-EDITORS' TOP 10 PICKS : PUMP UP THE ADRENALINE!

For modelers who want a jolt of excitement, flying aerobatic airplanes is just the thing to get the adrenaline flowing! Here are our 10 picks for the most aerobatic flying fun.

The popularity of high-performance acrobatic airplanes is at an all-time high, and in today's market, there's a seemingly endless supply of almost-ready-to-fly (ARF) kits to choose from. Today, most ARFs have the highest levels of quality and durability, and their prices are hard to beat when you consider how much it would cost to scratch-build a comparable model on your own. And how much is your time worth? If, like most of us, you don't have a lot of building time, then ARF acrobats are a speedy way to get up into the aerobatic "box."

Over the past few years, we've reviewed quite a few acrobatic ARFs, and this article highlights some of the best we've flown! Whether you're looking for a smaller Sunday-afternoon Aresti weapon, an electric cloud dancer, or a bigger gasoline-powered IMAC performer, you're sure to find something to excite you here.

When we developed the idea of finding the best acrobatic ARF, we put our biases aside and compiled a list of contenders. We sat down and talked about several key issues, such as the model's overall appeal and attractiveness, and we considered more tangible qualities, such as design engineering and overall execution. From how well they were packed into their respective kit boxes to how easily the model went together, we sorted through a lot of little details. We also took into account how well the models flew; after all, isn't that what it's all about?

If you've been looking for a great new aerobatic ARF but haven't yet made your purchasing decision, check out these great acrobats to see how well they stack up!

BALANCING ACT

FOR A MODEL-especially an aerobatic one-to fly properly, its center of gravity (CG) must be in the correct location. A nose-heavy CG is great for a trainer because it increases its inherent stability and makes the model more forgiving. But in an aerobatic plane, a forward CG decreases its ability to maneuver quickly; it must fight the stability! Start with the CG in the center of the manufacturer's recommended range. Slowly move the CG forward or aft until you find the optimum balance between aerobatic agility and stability. Test-fly your model after each adjustment, and note the model's response to control inputs. You'll know the CG location is correct when the model can enter and exit maneuvers easily without needing many corrections.

LATERAL BALANCE

Before you test-fly your model, be sure to balance its wing from tip to tip. Small nails or screws inserted into the lighter wingtip are useful for making minor balance adjustments. To check the lateral balance, roll the model into straight and level inverted flight and then center the aileron stick. If either wingtip drops, add weight to the lighter tip.

You can also test the lateral balance by flying away from yourself (directly into the wind) and then pulling the model up in to a tight loop. Make sure that you pull straight back on the elevator stick, and don't input any left or right aileron control. If the model exists the loop with one wing lower than the other, the balance is off. Add weight to the lighter wingtip, and test it again.

Use these fine-tuning tips to help "dial in" the flight characteristics to match your flying skills. Get comfortable with your model's response, and remember to make all balance changes very small.

SETTING UP FOR AEROBATICS

FLYING AEROBATICS is a great way to improve your piloting skills. A certain amount of discipline is required, but the payoff is gaining smoother, more precise control. You learn to think ahead and to act instead of react to what your model is doing. With improved skills also comes increased confidence in yourself and an extra margin of safety. Here are some fundamentals to build your aerobatic skills on.

* Make sure that your engine is properly broken in; it should idle reliably and have smooth throttle response. An onboard glow igniter is a good way to improve engine reliability.

* Make sure that your fuel system operates properly and that the fuel lines are not kinked or pinched within a tightly fitting engine cowl.

* Use foam rubber to wrap your radio equipment and secure the receiver and battery pack in the fuselage. Aerobatic maneuvers produce high-G forces and can cause the radio gear to shift out of place. If this happens, your model's balance can be affected; worse, a battery or servo connector could come loose!

* Use the proper servos. Aerobatics requires stronger, faster servos than sport flying does. The servo's ability to center precisely is also important for consistent control. Follow the model manufacturer's recommendations when you choose your servos.

* Because of the higher current drain caused by the servos, a larger airborne battery pack is also recommended. To play it safe, use at least a 1000mAh pack.

* Install slop-free control linkages. If your control linkages have too much play, it will be almost impossible to hold a precise line throughout a maneuver. Solid controls also minimize the chances of control-surface flutter, which can cause your model to crash.