Alex Voicu

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:

JRgraham

My Feedback: (1)

Alex, just finished reading your 'Groups' forum, and wow!

Outstanding work you have done!

Good luck on the kits, I would definitely consider this one!

Rendegade

Nice rendering, what did you use?

Doug Cronkhite

My Feedback: (34)

Alex,

Would you be willing to sell fuselage kits only?

Alex Voicu

Thanks for the comments. For the renders i used Solidworks 2007.

Doug,
Tommie is taking care of the kits manufacturing so it's really up to him but it shouldn't be a problem.

wagen017

Hi Alex and Tommie, congrats on release of this new plane!

Question: on the website you mention the plane is electric only. Is this correct?

Volkert

apereira

Alex,

Your CAD renderings are beautiful.


Very well done!

Alejandro P.

Alex Voicu

Thanks Alejandro.
Volkert, the model was designed for electric power only. With a little work i think it can be converted, but it's never been tested with glow power.

TimBle

Alex,<div>
</div><div>I am very interested in the Radiance and have spoken to Tommy in the past. My problem is time. I simply don;t have enough of it too build a Radiance from a Kit at this time. My job is demanding so I spend my time with my family or flying for a few hours.</div><div>Do you have plans for a glass fuselage version of the Radiance? Please no expensive carbon and kevlar fibres, these would not be needed in a 2x2 to achieve weight. Foam wings I could sheet myself but a glass fuse would cut down my build time significantly.</div><div>
</div><div>If Yes, I'll be camping out in the ticket line for one</div>

proparc

Alex,
What type of computer system does it take to run SW 2007 at this level. CPU, Ram, video card etc. Also, how do you get "cut files" out of Solidworks files?

Alex Voicu

Timble,
We have plans for a new composite model, but it won't be very soon. At the moment it's just a 3D model on the computer.

Proparc,
It's just a regular computer, it was not very fast even when it was new and it's now at least 3 years old. Rendering takes time, for such an image the computer works at least 1h.
The 2D drawings from SW were exported in dxf format, which is compatible with many programs.

TimBle

I ran ProE Wildfire 4 on my Dell Inspiron 5010.<div>3Gb ram and a 1GB graphic driver.</div><div>Just a darn pity I don't have a license for it anylonger now its dead </div>

TimBle

Alex,<div>
</div><div>By composite do you mean carbon glass or do you mean Glass balsa?</div><div>
</div><div>I'm not into Oxai level prices and I don;t believe the carbon/kevlar construction brings any real value to a model except high price.</div>

warrior10

Hi Guys,
I will hereby start the building thread:

warrior10

The second photo is just to show some detail.
It is important to keep it on the flat building bord until all the bottom parts are glued in.
More pictures will be added.

TimBle

excellent pics Tommie.<div>
</div><div>It looks to me as if the laser cut lower fuselage longeron assists with achieving a straight build without too much difficulty. </div><div>Excellent kit, congrats to you and Alex on this project.</div><div>
</div><div>5 thumbsup</div>

warrior10

Thanks for the compliments Timble,
Ya the midplane former gives a nice reference plane and it's no problem, even for a novice to build a straight body, assumed you're building on a flat,straight surface.

Alex Voicu

Found a few more pictures from Tommie showing the first steps in detail.
Fuselage is built upside-down, turtle deck and canopy area will be added later after removing the structure from the building table.

TimBle

thanks for the information on the Radiance Tommie and Alex.<div>
</div>

Alex Voicu

I attached a few images showing the motorbox and firewall assembly. We actually recommend carbon laminating the firewall and motor support plate, but they proved to be strong enough even without carbon.

Alex Voicu

Next is the battery tray and rudder servo support:

flyintexan

My Feedback: (1)

Alex, congratulations on your design (both the kit and the plane)! Beautiful work. Can't wait to see the rest of the build pics.

Best Regards,
Mark

Alex Voicu

Mark, thanks for the kind words. I will try to add more pictures every day if possible.

Today i received a few pictures from Tommie showing the kit content before shipping to a customer in Canada. Here they are:

wattsup

My Feedback: (1)

Alex, I must congratulate you and Tommie on a job well done. Like I told you a year or so ago, I believe you have a winner! Everette

Alex Voicu

Thanks Everette, i'm glad you like the kit.

More detail shots of the upper fuselage structure, nose and canopy frame area: