Siren C-30 Edelweiss (oz5214)

About this Plan

Robbe Siren C-30 Edelweiss. Radio control electric powered Glider. Kit # 3134. Plans show both a nose mounted folding prop version and a further power pod mount.

Update 29/04/2015: Added ribs and formers, hand traced, thanks to Julien.

Update 13/10/2019: Added kit review from RCM&E, September 1978, thanks to RFJ.

Quote: "Robbe Edelweiss. Review by Bill Burkinshaw.

For those modellers familiar with Continental kit imports the Robbe Edelweiss should present no problems. As with most kits of West German origin I have built, this design employs a stick part one to part two to part three sequence for construction. There is an English language translation which when used in conjunction with the copiously illustrated foreign language text language instruction enabled me to overcome any problem in reading the plan.

Construction follows traditional practice, employing an all sheet box construction fuselage with suitable internal stiffening in the form of longerons. spacers and formers. Diecutting of the thinner plywood parts was of rather disappointing quality whilst the thicker 1/8 ply parts were merely printed and required the use of a Dremel or hand fret saw to cut out. Parts for either an electric power, slope/thermal soarer or power pod version are included in the kit, the former version being that built for this review.

A geared motor with folding propeller system is available from Robbe. A complete set of parts and full instructions for installing this system are included in the kit. Power for the electric motor is supplied by a seven cell (8.4V-1.2Ah) power pack which is housed behind a sliding door underneath the wing position.

Two complete fuselage layouts are detailed on the plan illustrating clearly the different equipment layouts necessary for both electric and pure soarer configurations.

Wings: I started construction of my model with the wings which are of conventional built up construction employing webbed spruce spars but with no leading edge sheeting. Riblets are fitted between all the main ribs for the full wingspan and webbing of the main spar progressively reduces in strength from ply either side of the spars at the centre section down to balsa on one side only at the tips. The use of riblets and all that webbing certainly brings up the component count and whilst the wing construction is straightforward it is quite time consuming.

Wings are built flat on the board and the wash-out, which is a familiar feature of high aspect ratio tapered wings of this type, is incorporated at the covering stage. Wing joining is accomplished by pre-formed heavy gauge piano wire and tubes.

Fuselage: Fuselage construction is very straightforward, the most time consuming part being the installation of the electric power system and the 'do it yourself' mechanical mixer system for the Vee tail ruddervators. The motor mount has to be fabricated and the anti-interference suppression capacitors have to be fitted to the motor. All the necessary wires for connecting the power pack, motor and micro switch are included in the electric power pack which contains all details of the wiring circuit. I managed to solder all the joints with a 25 watt iron.

Halves of the vee tail are permanently joined using pre-formed piano wire braces, the whole assembly being retained with a dowel at the front and rubber bands at the rear. Some careful chamfering of the roots of the tailplane halves is needed in order that the correct 110° vee is produced and also the correct tailplane incidence is built-in. Templates (three in number) are detailed on the plan to assist with this rather tricky operation.

Control connections from mixer to control surfaces are by piano wire inside plastic snake tubes. I immersed the coiled plastic outer tubes in very hot water for a few minutes to soften them so that I could straighten the tube before installation. Plated adaptors are provided for soldering to the piano wire control rods. devises are also supplied for each end of the control cable. Soldering of these joints should be very thorough. clean the ends of the piano wire with emery cloth and use an acid flux cored solder or Bakers Fluid flux for the joints.

Equipment installation: I used Sanwa R/C equipment in the Edelweiss, three servos are used, rudder, elevator and electric motor on/off via the throttle control stick. An on/off switch for the motor is a necessity as over-discharging of the power pack is notconsidered to be good for it. Switching is by a micro-switch which incorporates a 'dynamic-braking' circuit to stop the motor quickly for positive folding of the propeller blades. There is plenty of room for modern R/C equipment but modellers with older largish servos may find the mechanical mixer may need slight modification and also the switch servo and receiver Ni-Cad layout may need revising... "

Update 15/7/2022: Added kit instructions, in German, thanks to Stephan Krings.

Supplementary file notes

Formers and ribs, 9 pages.
Instructions, in German.
Review.

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