Rockets on WWI biplanes?

??? I've been looking at several photographs in a
WWI aviation book and noticed what appeared to
be a French Neuport (type unknow) that has what
looked like firework rockets attached to the outer
struts between wings. Question: Were these used
for signaling or as an offensive weapon? If used as
a weapon, what were they used for? Strafing?
Catch something on fire? Also, how effective were
these rockets? Any background from you historical aces would be appreciated.

[PeterL]

These are "Le Prieur" rockets named after the naval officer who developed them (above right). They were an adaptation of an existing signal rocket and used for anti-baloon work. A blade set into the head of the rocket was designed to pierce the baloon fabric and the burning propellant did the rest. They were widely used and apparently quite successful.

[gregoire]

A bit more on Le Prieur and its rockey Le Prieur was born in 1885 in 1909 as he was the naval atache in japan he attach a glider his car and made the "first motorised fly" in japan As well as his famous rocket he create a self correcting device for aircraft machine gun that was widely use during the war post war he pattented a self contained diving suit that is the ancestor of the scuba he died in june 63

Now for the rocket they were used in a lot of plane farman MF11, Nieuport, spad ...
they were originaly made as anti airship weapon
the body of the rocket is 200gram
there is a penatration cone and a balast with either sand (anti balloon) or aluminiothermite (anti airship)
the palne is fitted with 8 or 10 rocket
each rocket is in a steel lauch tube long of 2 meters they are electricly fired (the propulsant is mad of black powder
The first attack with those rocket took place the 22 may 16 in verdun among the pilot were jean chaput and Nungesser a total of 6 balloon were destroyed (7 were attacked)

[WFS]

I seem to recall reading that Albert Ball tried firing Le Prieur rockets at enemy planes without success aside from scattering a German formation.

Wayne

[gregoire]

I am not surprise that Ball did not touch any german plane with the rockket the trajectory of the rocket were at best erratic (there are a couple of picture of rocket firing i will try to scan the one from the Dorme and Guiguet ) and you will see that none of the rocket is going in the same direction. to use against balloon the standard procedure was to fire in the wind direction (so the wind had an impact on the trajectory) from a stable position at about 120m from the balloon, it was asked to wait a couple of second for the rocket to be launched before changing the trajectory of its plane (it could take up to 4 second betwen the pilot press the fire buton and the last rocket exit its tube) a lot of pilot were saying that if you want one of your 8 rocket to impact you need to fire at no more than 100 metter form the balloon. against a plane I guess only a lucky shoot could do