Vous sentez-vous chanceux, Punk? A larger than average weapon.
Pic by my friend Colin McWiliams.
In
La Grande Gallerie at Le Bourget, Paris. I want one.
Andy Jones kindly gave me the details, over on Plane Talk: That be a Voisin 10 with a 37mm Hotchkiss quick-firer cannon. It was restored by your friends at The Memorial Flight Association for the museum.
Here taken from their website:-
"Early 1918, the Voisin 10 began to replace the Type 8. The basic design remained the same, but the 280hp Renault engine, more reliable than the Peugeot, was installed and the rudder was strengthened and inscreased in area. The machine, like the Voisin 8, was framed in steel-tubing with a covering of fabric; wings tips were square and the double ailerons, of equal chord, were connected by light struts. The nacelle had a flat profile like that of earlier canon-equipped Voisins and had a large streamlined fuel-tank mounted under the top wing on each side, a characteristic Voisin four-wheeled undercarriage was provided.
600 lbs of bombs could be carried (396 lbs for the Voisin 8 ). This was only a fraction of the load carried by the contemporary twin-engined bombers, but it was heavy enough to allow the French night-flying "escadrilles" to deal heavy blows on German manufacturing centres, notably the factory producing poison gas at Ludwigshafen, the target of the first notable Voisin day-bombing raid led by De Goys in 1915. One "escadrille", V.293, was employed entirely on night reconnaissance. A version of the 10 Bn.2 was armed with a 37mm Hotchkiss quick-firer canon. It was not used in large number and the gun was frequently removed.
900 Voisin 10 were built."
I can tell you that from reading 'French Strategic And Tactical Bombardment Forces Of World War One' by Rene Martell (Traslated by Allen Suddaby) [Scarecrow Press 2007]--on this month's Waterstones best seller list at number 4 (surely)

...that the cannon armed Voisins were sent out in advance on the standard night bombing Voisins to suppress AA and searchlights. A sort of early form of 'Wild Weasel' work..???
The French night bomber offensive in The Great War has been over looked in the English speaking world (like much else French in that conflict) but the French night bomber escadrilles were often putting up several hundred aircraft on strategic bombing missions a day in the later war period--both day and night raids. Many specialist aircraft were developed for the work--including long range escort fighters and all sorts of other strange stuff too.
Thanks to Andy and Colin.