Wiki F5L Electric 2m

The Wiki F5L is an electric version of the Wiki F3L, the well regarded fourth generation 2m balsa RES model from Tomas Hlavinka. It has had great reviews and competition success. F5L is the new name for F5-RES (Rudder-Elevator-Spoiler 2m electric glider built mosty from balsa) competition class.

The Wiki was developed in collaboration and consultation with several top pilots and aerodynamicists. It is the probably the ultimate electric RES model of 2023. The Wiki F5L draws on all the experience from five years of development, production and operation of its Kiwi and Wiki F3L glider predecessors and has incorporated important customer feedback from competition and recreational pilots from all over the world.

Like the glider version, the electric fuselage was designed to have a minimalist cross section for the least possible frontal drag and surface area. To this end the fuselage uses a small inexpensive 1507 outrunner of only 22mm diameter, and a 25mm spinner. Thus the fuselage maximum dimensions are 25mm wide and 39mm high.

The wing airfoil profile is inspired by the latest molded F5J models and then modified for RES building capabilities. The design emphasis was on increasing the penetration, this lead to reduced maximum thickness and camber. The airfoil thus produces less lift and so the weight of the airframe had to be reduced. Due to the now fully exploited potential of conventional construction, a unique and previously unused geodetic rib design was decided upon. This method increases the required wing stiffness by an order of magnitude. The result is a lighter airframe with greater stiffness, a thinner airfoil for high penetration, and a shallower wing depth for reduced drag. Less wing lift and the required low weight for the opposite of high lift after takeoff. The distribution of the profiles along the wing's semi-span ensures maximum performance even at very low flying weight and stability when circling without the need for major control inputs.

Ballast boxes are built into the wings, allowing 120g of ballast to be added when using steel slugs. Ballast sets (steel and hard wood) with a useful plywood box is available as a separate kit.

Flight tests show that the Wiki F5L can keep up with the best performing e-RES models in light air thanks to its lower weight despite the smaller wing area. In active air, however, it is even better and more versatile thanks to its greater penetration. Circling is stable and without a tendency to tighten, rudder response is immediate but adequate and the model handles well over a wide range of attitude and centre of gravity positions, making it very versatile. The wing spoilers can be deflected without affecting the model's trim. Landing on point is therefore precise and there is no need for wild elevator corrections.

Overall the Wiki F5L is a thoroughbred electric RES model, capable of winning F5L competitions in all conditions and rewarding both competition and sport pilots.

Wiki F5L Specifications
Wing span	2.0 m	79 in
Wing area	34.0 dm2	527 sq in
Length	118 cm	46.5 in
Flying weight from	390 g	13.8 oz
Wing loading	11.5 g/dm2	3.8 oz/sq ft
Aspect ratio	11.7
Wing airfoil	HP-RES 36-38
Dihedral (EDA)	12.0º
Spinner Diameter	25 mm
Centre of Gravity	83-87 mm from wing leading edge
Controls	Rudder, elevator, spoilers

Recommended RC
Rudder & elevator servos	KST X06H, KST X08H, KST A08H, CHA DS06, Blue Bird BMS-101DMG, Blue Bird BMS-101HV, Blue Bird BMS-115WV, Blue Bird BMS-125WV
Spoiler servo	Blue Bird BMS-101DMG, Blue Bird BMS-101HV, CHA DS06, Emax 9051
Receiver	4 or 5 channel receiver to match your transmitter

Control Throws
Rudder	35 mm each way
Elevator	10 mm up & down
Spoilers	80º - 85º up

Electric Powertrain Recommendation 1
Motor	T-Motor F1507 2700 RPM/V
Battery	Bonka LiPo 2S 300mAh, Bonka LiPo 2S 400mAh
ESC	HyperFlight 28A BLHELI-32, HyperFlight 30A BLHELI-32, HyperFlight 40A
Prop blades	GM 6.5x4, CN 7x4, OA 7x4.5
Spinner	CN Models 25mm Spinner for M5 shafts, VM 25mm Spinner for M5 shafts

Electric Powertrain Recommendation 2
Motor	T-Motor F1507 3800 RPM/V
Battery	Bonka LiPo 2S 300mAh, Bonka LiPo 2S 400mAh
ESC	HyperFlight 28A BLHELI-32, HyperFlight 30A BLHELI-32, HyperFlight 40A
Prop blades	CN 6x4, Grp 6x3
Spinner	CN Models 25mm Spinner for M5 shafts, VM 25mm Spinner for M5 shafts

Electric Powertrain Recommendation 3
Motor	T-Motor F1507 2700 RPM/V
Battery	Bonka LiPo 3S 300mAh
ESC	HyperFlight 28A BLHELI-32, HyperFlight 30A BLHELI-32, HyperFlight 40A
Prop blades	CN 6x4
Spinner	CN Models 25mm Spinner for M5 shafts, VM 25mm Spinner for M5 shafts

Wiki F5L Typical Weights
Bare structure	265 g	9.3 oz
Covering	50 g	1.8 oz
Total structure	315 g	11.1 oz
Receiver	6 g	0.2 oz
Rudder servo	5 g	0.2 oz
Elevator servo	5 g	0.2 oz
Spoiler servos	10 g	0.4 oz
Motor	15 g	0.5 oz
Prop & spinner	7 g	0.2 oz
ESC	7 g	0.2 oz
Battery	20 g	0.7 oz
Flying weight	390 g	13.8 oz

See this Photo Build Log for build info.