|Kappa 20 Specifications|
|Wing span||2.03 m||80 in|
|Wing area||30.0 dm2||465 sq in|
|Length inc spinner||112 cm||44.1 in|
|Flying weight from||623 g||22.0 oz|
|Wing loading||20.8 g/dm2||6.8 oz/sq ft|
|Spinner Diameter||32 mm|
|Centre of Gravity||78-81 mm from wing leading edge|
|Controls||Rudder, elevator, ailerons, flap, throttle|
|Kappa 20 Typical Weights|
|Fuselage||82 g||2.9 oz|
|Glass layup wings||260 g||9.2 oz|
|Tail Plane||13 g||0.5 oz|
|Fin||13 g||0.5 oz|
|Accessories & glue||18 g||0.6 oz|
|Total structure||386 g||13.6 oz|
|Wiring||10 g||0.4 oz|
|Pushrods||9 g||0.3 oz|
|Receiver||8 g||0.3 oz|
|Rudder servo||5 g||0.2 oz|
|Elevator servo||5 g||0.2 oz|
|Wing servos (4)||36 g||1.3 oz|
|Speed control||34 g||1.2 oz|
|Motor||45 g||1.6 oz|
|Prop & spinner||18 g||0.6 oz|
|Battery||67 g||2.4 oz|
|Flying weight||623 g||22.0 oz|
|Rudder & Elevator||Ripmax SD100, Blue Bird BMS-101HV, KST X08, MKS DS65K, MKS DS75K|
|Ailerons||Ripmax SD100, Blue Bird BMS-101HV, KST X08, MKS DS65K, MKS DS75K|
|Flaps||Ripmax SD150, KST X08, MKS DS75K, MKS DS6100, MKS HV6100, Corona DS843MG, Hyperion DS09-AMD, Blue Bird BMS-105HV|
|Kappa 20 Powertrain Recommendations|
|Powerline Micro 1010||3S 500mAh LiPo, 12x8 prop|
|Mega 16/15/4 direct drive||2S 500mAh LiPo, 7x4 prop|
|ADH300L Front Mount||3S 450mAh LiPo, 9x5 folding prop|
|ADH300L Front Mount||2S 450mAh LiPo, 11x6 folding prop|
|Dualsky XM2826CA-10 45g outrunner||3S 500mAh LiPo, 10x7 prop (19A, 5.0 m/s)|
Review by: Brian Rivas
It was never my intention to have an E-glider, as my staple diet for the last 12 years or so has been DLGs and sailplanes, but the grass in the two local fields I use has lately been so long as to prevent proper launches of anything. A hay crop has been taken now, but I've wasted a good few flying weeks.
And so I decided to try an E-glider for when ground conditions are not ideal - and big thanks, as ever, to Neil for his patience and advice. I wanted something that was small enough to carry to the local field without dismantling, but large enough to be interesting. I was tempted by the Blaster 2e, which would have been a nostalgic trip, as my first serious DLG was a Blaster 2. But I liked the look of the Kappa 20, and I am pleased I made that choice. It arrived very quickly, all parts generously bubble-wrapped and suspended inside a sturdy cardboard box. Neil excels at packaging, as well as giving a first-class service in every way.
This is a really beautiful model with impeccable workmanship, and I love the swoopy lines of the wing. I also admire the way the designer has done everything to eliminate drag: aileron and flap actuation is internal with no external horns, and the elevator and rudder gaps have been sealed.
The other reviewer on this page mentions that the tailplane boltholes are slightly off-centre. It certainly looks that way, or is it merely that the longitudinal carbon reinforcement is off-centre? I did a lot of measuring and at first I felt they were spot-on, but then I wasn't quite so sure, so have opened them up a bit so that the tailplane can be aligned absolutely perpendicularly. As Ian says, it won't affect the performance, but....
The other point he makes is that the aileron pushrods need a bend in them. They are situated in the servo wells and rest firmly against the inside of the wing's upper surface. If they are pulled up at an angle to slip into the servo arm, the ailerons will not operate properly and are extremely stiff.
It would be possible, I suppose, to mount the servo on a block and have the arm pointing downwards, but I didn't feel happy about that idea, so I bent the front part of the rod upwards, leaving the rear of the rod flush with the wing's inner skin. This works fine, but the rods are short and very stiff and I had to use two pairs of long-nosed pliers to form the bend. Great care is needed, as a slip under pressure could cause damage. to the wing. The flaps are not an issue, as the pushrods are more free-floating.
For power I will be using a Powerline Micro 1010 Turbo, a simple Hobbyking 30A ESC, and a 3S 500mah Turnigy Graphene lipo.
Servos caused a little head-scratching. The manufacturer recommends D47 and D60 (Ripmax SD100 and SD150) - certainly something thin is needed if one is to avoid bulging servo covers and adhere to the designer's intent of minimising drag. These fit all right, but I really wanted MKS DS65K's for the ailerons, although their arms have a substantial boss and I did not think I could drill a pushrod hole close enough to the servo without the arm protruding below the bottom skin of the wing. But I could - just - and very little throw is needed to get enough movement on the ailerons.
For flaps I will use KST XO8N's, and DS65K's for elevator and rudder. Pull-spring actuation a la DLG's is possible here, or 1mm carbon rod in 1.68mm teflon tubing.
The Kappa fuselage is very slim, but there is plenty of room for all the gear. The belly hatch is a neat access point.
I'm excited about my first venture into E-gliding, and very happy with my choice of glider: the Kappa is a beautifully executed design - light, strong and sleek, and looks as though it means business. Hope to be flying in a few weeks.
Review by: Ian
Received my Kappa 20 very promptly, and well packaged as one would expect from Hyperflight.
Assembly was pretty straightforward if a little fiddly. The quality, and fit of the various parts was excellent, with one minor exception; that being that the 2 bolt holes to fix the stab to its pylon were slightly offset each side of the center-line, so the stab is a few degrees off perpendicular to the boom. Unfortunately, I didn't notice this until I was admiring the completed model, and i'm sure it has no effect on the model's flight.
I also feel that a slight crank in the aileron pushrods would have been helpful to the assembly.
In flight it is fairly similar to my old Sprite it has replaced, fairly fast for a thermal glider, and requiring full concentration as its slim profile leaves it prone to disappear at height! It sniffs out lift very well, and circles tightly. An excellent model.