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CAUDRON G.3 TECHNICALITIES
I UNDERRATED technical nuances of René Caudron’s G.3, the aeroplane flown by Frenchwoman Adrienne Bolland in her 1921 conquest of the Andes. Describing the G.3, I termed it “of the spit, wire and strut variety when introduced in 1913…. decidedly not state of the art in 1921.”
True enough, but new awareness of the aircraft came to me through the enthusiasm of another Frenchwoman, Coline Béry. What’s more, this encouraged me to begin a GMax version of the G.3 for use in Microsoft Flight Simulator.
Coline is author of TRUE BIRDS: Searching for Adrienne Bolland’s Two Legendary Planes, 2015/2016, available in French, Spanish or English. She kindly offered me an early reading of the English version, from which I learned more about Bolland, René Caudron and his aircraft.
Adrienne Bolland, 1895 – 1975, French aviatrix. René Caudron, 1884 – 1959, French aircraft manufacturer.
Gaston Caudron and his younger brother René founded Sociéte des Avions Caudron in 1909. The G.3 was one of the Caudrons’ early production successes. Gaston perished in an aircraft accident in 1915; Réne continued in the business until the fall of France at the start of World War II, his company acquired by Renault in 1933.
Watercolor of a Caudron G.3, from L’Illustration (“The History of Aeronautics”). Image from The Legend of the Skies. I love the airy Impressionism of this one.
Béry’s book True Birds includes several G.3 engineering drawings, illustrations and many photographs, the kind of original material that encourages GMax modeling. What’s more, the G.3’s “spit, wire and strut” nature translates into a modeler’s delight: Much of the aircraft’s operation is out in the open for all to see.
AEROPLANE CAUDRON G.3. Carlingue à double commande. This and the following image from True Birds.
The French word Carlingue, cabin, exaggerates the level of comfort provided for its flyers. Indeed, Google Translate offers cabine de pilotage as French for cockpit, a more accurate description of the G.3’s affinity with the environment. Its dual-control setup suggests the aircraft’s use in pilot training, typically with the instructor seated aft.
Several interesting technicalities are evident in the schematic of the G.3’s control of wing warping (gauchissement) and rudder (palonnier). Though not stated, elevator control is also shown. Note the cockpit’s stick and rudder bar linked to various control wires.
Commande de gauchissement et palonnier du Caudron Type G.3.
The elevator wires cross aft of the control stick and angle to stationary struts mounted on the left and right of the aircraft’s horizontal stabilizer (this last component not shown in the schematic). From there, on each side, the wires fan out into three at the top and another three at the bottom of the elevator.
Note, there were no elevator horns on the G.3. Ordinarily, a pull on the top horn raises the elevator; a pull on the bottom one lowers it. Curiously, photos of modern G.3 restorations show these conventional horns, maybe suggesting enhancements of the original elevator control.
This restored G.3 has conventional elevator horns. Image from primeportal.net.
Control of its dual rudders was also unconventional, again sans control horns. Rather than duplicating wires to the dual rudders, the G.3’s rudder bar was part of a single circuit, one wire traveling aft to the left and the other aft to the right. A pair of central wires kept the two rudders in unison. The schematic indicates that upper portions of the stabilizer struts evidently were fitted with two pulleys, one for the rudder wire circuit, the other for the elevator’s “up” wire.
A work in progress. Rear three-quarter view of my partially modeled Caudron G.3, complete with Adrienne Bolland.
Last, the G.3’s roll control came not from ailerons, but from wing warping, already old hat by its 1913 introduction. As shown in the schematic, lateral movement of the control stick exerted tension either left or right on the central lower wire. This tension, in turn, acted upon the trailing edge of the wing on that side—and, through its routing, an easing of the trailing edge of the opposite wing.
Rolling to the left, from stick action to wire tension to wing warping.
In the diagram above, I’ve inserted arrows showing how the control stick brings about wing warpage generating roll to the left.
Now, imagine all these wires rattling in the wind, the structure tossed this way and that by air currents, the aeroplane barely making headway with its 80-hp rotary spinning with the prop and adding its own dynamical input.
A work in progress. Wheels, struts and other things to come.
Flight pioneers like Adrienne Bolland were a world apart. ds
© Dennis Simanaitis, SimanaitisSays.com, 2016
Simanaitis Says 
Hi DrD,
The structure of the G3 is nearly pure Voisin with the widely-spaced rear frames between which Voisin put the propeller. Caudron used that space for the second seat and put the engine in the front of the pod. Voisin used the front of the pod for the second seat where a person could “do something” throw out a bomb, aim a camera, observe, unobstructed. The pod is virtually the same size, simply moved rearward with its engine at its opposite end. Most of the flight controls are also Voisin, who, according to this typer, invented all those control surfaces and systems and put them in production in their aircraft factory in 1905. The Wright brothers never built an airplane in their history, they did build a effective flying machine, but it was a kite and they never developed it any further.
Just one old guy’s opinion. Let the slings and arrows fly. —Crane
I just realized Caudron used the Voisin frame and the Wright wing, without Voisin’s ailerons. Hum…
Dennis! What a surprise! The Caudron was the first trainer of the Venezuelan Military Aviation School (EAM). A restaured one was purchased in France in the early 80s for our flying “Legendary Squadron” and is currently exhibited only military aviation museum. I do have several pics of that one and can send you details as needed! Just ask!
Hi, Alejandro,
Actually my G.3 is completed. Coline Bery provided lots of info. Many thanks.
Dennis
So, where can we get it???