Raven II (oz7032)

About this Plan

Raven II. Radio control flying bird model. A two channel R/C glider.

Quote: "If you enjoy watching birds soar, then perhaps it's time you had a Raven of your own. Raven II by Robert G Hoey.

All of us in the aviation community have at one time or another observed a sea gull maneuvering for food at the beach and asked ourselves - How did he do that? The pat answer (which is a cop out) is that the birds have sophisticated computers and lots of servos so they can do things that we can't do. Although that may be true, they still must operate within the same rules of aerodynamics and physics as we do and we know very little about how they utilize those rules. How can they fly without vertical fins or rudders? How do they generate turns? Although there is no shortage of speculation, we have been unable to positively answer these questions by merely observing.

Since large floating birds appear to be relatively passive while in soaring flight, and since they are of the same general size and wing loading as an R/C model, I reasoned that I should be able to learn something about the stability and control of birds by building an exact scale model of a soaring bird. The Raven was chosen as the subject since they are plentiful in the California desert for observing, and since they soar with their wings essentially flat, making for easy construction. Telephoto and video pictures were taken of ravens as they circled in thermals.

After analyzing about a dozen photos, an 'average' planform and configuration was chosen as reppresentative of a soaring Raven. My expectations were not very high. l felt that if I could achieve one controlled, straight gliding flight off of a hill, the experiment would be a succss. Several small profile models (6 to 8 inch span) were constructed from 1/32 sheet and tossed around the living room.

To my surprise, I found that the configuration was basically slable without any alterations or additions. Glide angle could be controlled in the normal manner with combinations of tail deflection and CG position. Getting the little models to turn was more of a challenge, but several methods that are consistent with observed bird behavior looked promising and I proceeded to build a prototype full-scale R/C model of a soaring Raven.

After a few hand glides and minor adjustments it was apparent that a stable and flyable Raven model glider was feasible without resorting to any tricks. My model flying partner, John Manko, suggested that development could be accelerated if we air launched the Raven model from the bottom of his Senior Telemaster (oz5044). A launch mechanism was installed and over 200 successful launches have been made. The air launch technique was the key to accomplishing controlled and repeatable experiments.

After two years of experimentation and the successful development of a Raven glider, I began to realize that I was entering into an entirely new world of flight. Hundreds of experiments came to mind: many more than I could possibly do alone. Experiments that could be done one at a time under controlled conditions, then later combined as appropriate. Fore and all wing articulation, wing sweep versusdihedral trade-off, fanning and contracting the tail area..."

Quote: "RAVEN 2. pl-1160
Article and Plan derived from 1st generation scans. Jan-94. Hoey, Robert G.
Span: 50-inches. Glider. 2-channel

NOTES:

1. An aileron modification for the wing appeared in Feb-94 as RCM Plan # 1160a. The scaled plan was located in post 3568 (by Ian) and the article images in post 3559 (by Ray). I have brought them here.

2. The article was 13 pages and so all is placed in a single zip file; both articles and both scaled plans, as PDFs "

Supplementary file notes

Article (13 pages, complete).
Aileron mod plan.
Aileron mod article.

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