"Show Flyer" 60 Size 3D ARF from Hobby Lobby Int.

The Graupner ShowFlyer is a highly pre-fabricated ARF for 3D style aerobatics. It is distributed in the U.S. by Hobby Lobby Int. and is designed for a .60 size glow engine. The ShowFlyer is an impressive 3D performer.

A so-called "3D" plane is the new term for the original "funfly" models. They usually have thick and aggressive airfoils, lots of lift, plenty of drag, and huge control surfaces. For all their intimidating features, they are merely over-grown parkflyers that fly with great ease, maneuverability, and stability. They can take off and land in relatively small fields or parking lots.

Here are the plane specifications:

Specifications:

	Graupner ShowFlyer 60-size 3D ARF ($295)
	Wingspan = 60.5" (1540 mm)
	Wing Area = 1240 sq. in. (80 dm2)
	Length = 64" (1630 mm)
	RTF Zero-cell weight is 80oz (2268 grams).
	APC 20x11 e-prop

The Graupner ShowFlyer conversion uses the MaxCim 13Y brushless motor, a Model Electronics Corporation (MEC) MonsterBox 4.36:1 (96/22), and an APC 20x11 e-prop on 24 cells of Sanyo CP1700SCR.

20-cell Setup:

	Ready-To-Fly (RTF) @ 112 oz. (3175 grams) with 20-cells of CP1700
	MaxCim MaxN32-13Y brushless motor
	MaxCim Maxµ35D-21 Controller
	MEC MonsterBox geared 4.38:1 (70T/16T)
	800 watts at 41 amps
	180oz Thrust at 4500 RPMs

24-cell Setup:

	Ready-To-Fly (RTF) @ 124 oz. (3515 grams) with 24-cells of CP1700
	MaxCim MaxN32-13Y brushless motor
	MaxCim Maxµ35-25BEC Controller
	MEC MonsterBox geared 4.36:1 (96/22)
	1100 watts at 43 amps
	210oz Thrust at 4900 RPMs

The 24-cell setup uses the newer MaxCim Maxµ35-25BEC Controller with BEC (Battery Eliminator Circuit). The BEC feature reduces the weight of the plane almost 4oz by eliminating the need for a receiver battery pack. Additionally, the hassle of keeping the receiver battery properly charged is also eliminated.

Mounting the Motor:

The standard firewall mount kit (G96307-1) from MaxCim Motors was used to mount the 13Y brushless motor. The motor mount kit is light yet strong. The motor is solidly secured to the mount via the included metal hose clamp. It is held to the plywood firewall by 4 screws and weighs a mere 0.8 ounces with the clamp. When using an offset gearbox like the MEC MonsterBox, the resultant footprint is very similar to the intended stock glow engine. The gearbox drive shaft can easily be aligned to the center hole of the fiberglass cowl.

Alternatively, the Inner Demon gear drive can be used with either one or two MaxCim 13Y brushless motors to power models up to 1/4 scale. The Inner Demon gear drive and 13Y motor are shown below mounted to a PVC end cap using the MaxCim (G96307-1) standard firewall mount kit. The PVC end cap allows the 13Y motor to be clamped at a distance away from the firewall when additional extension is needed to fit the cowl.

To help cool the motor in flight, slotted holes were drilled into the cowl front on each side of the prop opening. Then five 1/2" holes were drilled in the bottom of the firewall below the mounted motor. The airflow exit hole was created by simply removing the small hatch under the bottom front of the fuselage. In this manner, cooling air can flow across the motor from the nose of the cowl to the bottom hatch opening.

The 20 cell setup is split into two 10-cell packs. The top pack was secured with a GWS R4-P receiver foam pad, which measured about 4" by 2.5". This was later replaced by an additional 4-cell pack to boost my power level to 1.1 killowatts using 24 cells. An alternate method would be to use two packs of 12-cells. Either size would fit just fine in this model.

Flight Report:

Initially, the MaxCim 13Y brushless motor used 20-cells with a 4.67:1 (70/15) gear ratio and an APC 20x11 e-prop. The plane had great power for many advanced aerobatic maneuvers. It took off in about 20' and landed in a very short distance as well. It flew very stable both upright and inverted. The flight performance was fantastic!

Although the power level was excellent, additional power was required for unlimited vertical or to pull up out of a hover. In theory, a 17T pinion (70/17=4.12) would yield about a 46 amp current draw. This change alone would increase my power significantly.

Alternatively, the new 25-cell controller from MaxCim Motors, the Maxµ35-25BEC controller, also had a built-in BEC (Battery Eliminator Circuit). This is a true controller BEC in that it provides 5.0v DC at 3 amps with a 4 amp peak capability and cuts off the motor if the input voltage drops below 4.2v DC. The new MaxCim controller was tested on 24 cells with a MEC MonsterBox geared 4.36:1 (96/22).

The new 24 cell power level was fantastic! There was more than enough power to provide long vertical runs and hover at about 3/4 throttle. The current draw of 43 amps was similar to the 20-cell setup but the RPMs jumped from 4500 to 4900 using the same APC 20x11 e-prop.

Conclusion:

MaxCim owner, Tom Cimato, holds the ShowFlyer after a successful test flight.

The Graupner ShowFlyer is a great flying plane! The conversion project to electric power was very successful and it was also a great deal of fun. By providing the ShowFlyer with a clean and quiet electric power system, it was able to fly just about anywhere! The advantage of not using a noisy glow engine allowed an increase in practice time since it could be flown more often.

Although the ShowFlyer has a big 61" wingspan and weighs over 7lbs, it flies very gently and is easy to land. The ShowFlyer can be flown very slow due to its aggressive D tube airfoil. It can be flown close to the ground either upright or inverted. Since the model is capable of performing most any maneuver, it will provide a great learning experience for many flights to come.

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