Simprop Zaunkönig

The Simprop "Zaunkönig" ("wren", small bird) is a small biplane design from way back (30 years?). At the time it must have been the smallest commercially available RC kit. It was powered by a small cox engine, and with the RC gear of the time the weight resulted in a model that's fast and challenging to fly.

First flight on 05/05/2018.
Wingspan  410mm
Weight 290g
Motor 1000 RPM/Volt
Prop APC 7x4 SF
Battery 3S, 800mAh LiPo

Found a kit on ebay, and created my own CNC-cut duplicate from that.

Some of the parts:

Assembly (and sanding) required:

Graupner BO 209 Monsun

The original Bölkow BO 209 "Monsun" was built around 1970, with almost exactly 100 copies being manufactured. As long as I can remember, Graupner always had at least on model in their catalog, from a small free-flight, rubber-powered variant to larger R/C types.
This model is based on a plan of the older 1973 Graupner kit for a 40-sized model.While the kit included foam-core wings, the rebuild has traditional ribs-and-spars balsa wings.

Wingspan	1.5m
Length	1m
Weight	2180g (kit used to be 2700g)
Motor	AXI 2816/12 V2, kV 760
Battery	4S 3000mAh LiPo
Prop	12x8
Max current	40 Amp

First flight: Evening of April 1, 2018.

Initial cockpit detail.

Special challenge in the rebuild were the bubble canopy and the motor cowling, which were vacuum formed. Above is example of the wooden cowling plug used to pull the cowling.