Purito Electric 2m

The Purito Electric is probably one of the best 2m build-it-yourself electric F5L RES model currently available.

The Purito is a direct descendant of the Pures and the Slight the Schweiger family concern have optimised the design as far as possible with current (2020) CNC technology. The main design change is to a lower aspect ratio wing to increase the Reynolds Number and give better overall performance and particularly nice handling. Despite the larger wing the weight has been kept the same, resulting in a lower wing loading and excellent performance in weak conditions.

The Purito flies like a homesick angel and despite its light weight the model has a surprisingly good speed range. As Greg wrote in the RCGroups thread “The big wing bestows a good launch, even when the wind is light; the airplane itself has little drag, so displays very good legs; handling is easy, allowing the pilot to concentrate on thermalling; and finally, the spoilers really make spot landings quite easy.”

The amazing wing is the major improvement of this design. The main spar is a substantial carbon tube which gives the structure excellent rigidity. A multitude of ribs are threaded over this tube to give the airfoil shape. This is even better maintained over the critical front portion by utilising two sub-ribs between each full rib, almost eliminating covering sag, and reducing drag appreciably. Becuse the tubular spar is inset below the covering surface there isn’t a discontinuity at the spar line which is great feature – this usually trips the boundary layer and causes extra drag.

The kit is beatifully made up with excellently CNC cut balsa and ply parts. The wing is built over/in a 3D jig which ensures all the ribs are perfectly placed and aligned. This can be seen in the clear photos in the English build manual. In addition to the manual, full size plans are povided for the tail surfaces. Also see the RCGroups Purito thread for detailed build info. Also use Google Translate on this very useful RC-Network.de Purito thread. Before building please checkout this link to the latest manuals and translations.

Purito Electric Specifications
Wing span	2.0 m	78 in
Wing area	39.7 dm2	615 sq in
Length	119 cm	46.9 in
Flying weight from	478 g	16.9 oz
Wing loading	12.0 g/dm2	3.9 oz/sq ft
Aspect ratio	10.0
Wing airfoil	AG35-38 modified
Dihedral (EDA)	12.0º
Spinner Diameter	30 mm
Centre of Gravity	75-80 mm from wing leading edge
Controls	Rudder, elevator, spoilers, throttle

Purito Electric Typical Weights
Bare structure	300 g	10.6 oz
Covering	50 g	1.8 oz
Total structure	350 g	12.3 oz
Wiring	6 g	0.2 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	39 g	1.4 oz
Prop & spinner	12 g	0.4 oz
ESC	5 g	0.2 oz
Battery	40 g	1.4 oz
Flying weight	478 g	16.9 oz

Recommended RC
Rudder & elevator servos	Blue Bird BMS-101DMG, Blue Bird BMS-101HV, Blue Bird BMS-A10H, KST X06, Graupner DES 427, ES08
Spoiler servos (2)	Blue Bird BMS-101DMG, Blue Bird BMS-101HV, KST X06, Graupner DES 427, ES08
Receiver	4 or 5 channel receiver to match your transmitter
Battery	2S 400-600mAh LiPo, 3S 400-600mAh LiPo
ESC	Hyperflight 11A BLHELI-32, Hyperflight 30A BLHELI-32, Sunrise 10A Pro, Sunrise 20A Pro

Control Throws
Rudder	20 mm each way
Elevator	10 mm up & down
Spoilers	80º – 90º up

Electric Powertrain Recommendations
Hacker A10-7L geared 4.4:1	3S 450mAh LiPo, 12×8, 13×8
DYS D2225-19	2S 450mAh LiPo, 9×6, 10×5
DYS D2225-19	3S 450mAh LiPo, 7×3.5, 7×4, 8×4
ADH300L / MM1914-1100 Front Mount **	2S 450mAh LiPo, 11×6
ADH300L / MM1914-1100 Front Mount **	3S 450mAh LiPo, 8×6, 9×5

** This motor will need a small widening of the internal fuse space to fit.