DC Gyro (oz14255)

About this Plan

DC Gyro. Radio control sport auto-gyro model.

Quote: "A Direct Control R/C Autogyro, by Emilio Cabezas. I became interested in model autogyros about eleven years ago, when I built a single rotor R/C model with four articulated blades and fitted with a .25 engine, which, after many tests and modifications, only made a short flight.

Sometime later I was inspired by a couple of photos of John Kallend's single rotor autogyro (later known as 'The Whistler') which first appeared in the Feb '87 issue of this magazine, so I built a small .10 engined model having a 2-blade teetering rotor and a small wing with upturned tips for lateral stability; control was by conventional tail surfaces. With this configuration, the tiny gyro (it weighed 26 oz only) flew very well. This encouraged me to go on building and experimenting with autogyros. I later removed the stub wing and fitted upturned tips on the stabilizer for the same purpose; the rotor head was also modified in order to have the blades individually hinged at the roots for flapping; control was still by rudder and elevator.

With these features, several models were built, using 2- and 3-blade single rotors and .10 to .15 engines, all of which flew great. I started being known as 'the autogyro flier' at my flying club, for I was the only one there trying to tame these types of models. This is an unusual modeling subject even in Spain, where this flying machine was invented in the early twenties by Juan de la Cierva.

I like all autogyro types. I have built and flown dual, side-by-side mounted rotor models and also a Synchrogyro, with two 2-blade intermeshing rotors, based on a design of lifetime French autogyro modeler Georges Chaulet. However, most of my designs have been of the single-rotor, flapping blades type. I like them to resemble the full-size autogyros of the thirties, and I try to incorporate the main features of these machines.

As most of you will know, an autogyro is a rotorcraft whose unpowered rotor keeps turning under the effects of the relative wind in forward flight or even in a vertical descent. In addition to the discovery of autorotation, Cierva had the bright idea of articulating the blades by means of flapping hinges which allowed them to move up and down. This way the problem of dissymmetry of lift was resolved and, after many unsuccessful trials, the autogyro could fly. Up to then he had employed rigid rotors, and the machines always rolled to one side before leaving the ground because of the higher lift produced by the 'advancing blades' (turning in the same direction the autogyro is moving) and the lower lift on the "retreating blades" (turning opposite to flight direction).

In the early thirties, Cierva introduced a major development: the so-called 'direct control.' With this system, control was achieved by tilting the rotor hub (axis of rotation) and hence the rotor disk in all directions, making it possible to dispense with airplane-type control surfaces which were rather ineffective at low airspeeds. Direct control was a mechanically simple solution that led to an important improvement in control characteristics of autogyros. This control system is still used on full-size ultralight gyroplanes..."

Direct submission to Outerzone.

Scan by MarkD, cleanup by Circlip.

Supplementary file notes

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