Chevrons on French pilot's sleeve?

[charles]

In this photo of two pilots from Escadrille 23, Georges de Ram on the right has four chevrons ^ like so on his left sleeve. Can someone tell me what this signifies? I believe this is length of service but I think there is a arther complicated formula for each chevron.

Also, the pilot on the left, Jean Baumont, has a horizontal (not vertical) stripe on his lower right sleeve. Is this a wound stripe? In the RFC and RAF a vertical stripe would signify that, but I am not sure about the French air service.

The photo was likely taken in May 1917. More information about these pilots is available at The Aero Conservancy at http://www.aeroconservancy.com

Thanks for your help.

Charley Gosse

[gregoire]

the chevron are effectively service time chevron they were created in april 16 and were given for a certain amount of time spend in the zone of the armies (in fact in position were an army was fighting) or to simplify any place close to the trench (add salonica and a few other place).
they were given to anybody that was physicly present in the area (an army acountant will get it the same way as an infantrymen)
the method of calculation change during the war at some point is was the first for 9 months, and the other for six it soon changed with a simpler method as one for six months
the calculation was complex as it wasn taking into account the number of day in the army zone if a full months (for 1st to the last days of the months) was not made in this case 30 days were equivalent to a month

for the horizontal stripe (I can not see it) it look like a rank insigna (it should be present on both arm and denote a sous lieutenant or an aspirant or an adjudant (they all have horizontal stripe with a few difference)
if you can send a zoomed picture of the area I will have a closer look

Here's the photo

Hope this worked:
[IMG]URL[/IMG]

[gregoire]

yes it looks like a rank insigna
I can not say if it was a sous lieutenant (plain silver or gold bar)
an aspirant (silver or gold bar verticaly separetd in 3 by two black vertical small stripe)
or and adjudant or adjudant chef (metal bar the color depend of the rank and of the unit with a red line in the middle)