Some of you may have followed a while ago the build thread of the first Radiance prototype [link=http://www.rcuniverse.com/forum/m_8962198/mpage_1/key_/tm.htm]here[/link] on RCU.
Short history of the development process
After building and flying the first prototype, i soon started looking at a short kit version of the model. Using the experience gathered during the building process of the first Radiance prototype, i made a few improvements to the external shape of the fuselage and also completely redesigned the internal structure to reduce weight. I also decided to design new swept wings and stabs for increased stability.
At the same time, my friend Tommie Prinsloo from South Africa joined the project. He owns a company named Aviaform specialized in manufacturing, design, prototyping etc. that manufactures the Radiance kits. In a very short time, Tommie built and tested the V2 prototype which had a glassed/painted fuselage and balsa/foam construction wings.
The large dimensions of the wing foam cores would increase the shipping costs significantly, so we decided to make another step forward and design balsa structure built-up wings and stabs, that would fit inside a smaller box. More modifications were made to the fuselage structure for increased stiffness of the fuselage skin and slight repositioning of the wing.
To test the new built-up wings and the other improvements a new prototype (V3) was built and successfully test-flown. Weight was 4850g, all film covered. We didn't have competition balsa available, so i'm sure it's possible to build it even lighter. The final version that we are offering as a kit is based on this version, but it does have enlarged ailerons for better snaps at low speeds and other small refinements.
A lot of effort went into getting the CG right for the final version (V4). I personally used Bryan Hebert's triangulation trimming method, which worked very well but requires a forward CG position (~25% MAC), which initially was difficult to achieve on the first prototype. Other people prefer their CG around 30-35% MAC and use a mix for KE flight. At the same time, glassed and painted fuselages are more likely to be tail-heavy compared to the film-covered ones, so we had to consider all these factors and repositioned the wing until we got the CG position in the desired range.
We put together a small website where you can find more info, a small image gallery, samples from the instructions manual, contact details and other things:
[link]http://www.radiance-f3a.com[/link]
Tommie will soon start adding here pictures from the building process of the prototypes. You may notice a few differences between the pictures and the kit (the most obvious being the longer ailerons on the final version) but these are part of the development process.
Please let us know if you have any questions, we will be happy to answer as soon as possible.
About the content of the short kit
We tried to keep the price as low as possible, so there are a few parts that need to be purchased separately. Parts like the wing and stab tubes are not available in South Africa, so ordering them for you and including them in the box would be significantly more expensive.
Included in the Short Kit:
- Laser cut interlocking balsa and plywood parts for the fuselage, wing and stab construction
- Fiberglass canopy
- Fiberglass cowl
- Fiberglass spinner and CNC machined aluminium backplate
- Paper Plans and instructions CD
What is needed to complete:
- Balsa sheets to cover the airframe (lightweight competition balsa)
- Landing gear, tailwheel and wheel pants
- Wing tube: PBG Composites 1" x 30" - Tube & Socket Set (Code PBG107TS)
- Stab tube: PBG Composites 7/16" x 12" - Tube & Socket Set (Code PBG90TS)
- Carbon fiber cloth to laminate firewall and gear support
- Paint or film covering
And finally a few computer images of the bare structure:
