Le Prieur Rockets

[William]

Gentlemen,
Does anyone have access to specifications, technical drawings, or an original rocket D or Z for reverse engineering? I remain intrigued with these no matter how useless they really were.
Regards,
William

[SCMc]

I found this at http://www.wwi-models.org/mail-archi...1995/1883.html

"A cardboard tube filled with black powder. A wooden conical head is
attached by doped paper or linen tape and has a triangular knife blade
inserted in a slot across its' apex rather like a spear point. A square
section pine stick is taped to the rocket with about 1.5 metres (5 feet)
extending from the base of the rocket. This fits into a tube attached to
the aircrafts interplane struts. The article says that the stick was
slightly thicker at one point which "allowed a good fit but not too
tight"


The rocket was discharged electrically by switch from the cockpit. Safety
breaks were also made in the rockets wires for obvious reasons.


The rockets _may_ have been dark red but Woodman is not entirely
convinced.


Quoted by Harry Woodman in Windsock, from Recherches et Inventions, April
1935:


"The rockets were charged with about 200 grams of black powder and at the
front they had a wooden penetration cone to which was fixed a triangular
knife blade. The rockets were launced by an electric switch in the
cockpit, in groups of several ata a time (bouquet!). The aircraft was in
a nose dive at the time of ignition and the rockets launched at a range
of 200 metres woulds penetrate the envelope of a German 'sausage' and set
it on fire thanks to the stream of incandescent matter which continued to
spout from the rear of the rockets. On May 22nd 1916, the 'rocketeer'
Charles Nungesser and five other great war aces effectively participated
in the recapture of Douamont, setting afire most of the Drachens along
the 35 km front, depriving the German general staff and most of the enemy
artillery of valuable information. Mr Le Prieur's invention caused the
destruction of about 50 German kite baloons."


An American observer is quoted from a US War Dept report of Dec 1916


"The fire is commenced at 100-150 metres whilst diving at an angle of 45
degrees. The steeper the dive the greater the trajectory and the more
effective the attack. The attack should be made in the direction of the
length of the baloon and against the wind... the ring of the front sight
permits the pilot to calculate the distance at which the firing is to
commence ..... the pilot should fire as soon as the balloon fills the
front ring.


The discharge of the rockets does not occur immediately the button is
touched and the delay varies slightly from one rocket to another. It is
absolutely necessary to continue to hold the target in sight and the dive
until the last rocket has been discharged. If the pilot breaks off or
pulls out of the dive too quickly the last rockets will go in different
directions and give a dispersion which is altogether inadmissable."

I don't know if that provides anything that is helpful. Considering they accounted for 50 German balloons, they were not entirely useless.

This says that they were fired "several at a time." Does this mean all eight at once, four at a time, or something else?

Steve

[William]

Hello Steve,
Many thanks for your kind reply. This was helpful and will assist in tracking down more info. A similar reference indicated that they were 2 meters in overall length and the propellant was 200 gms of "Ruggieri propellant" (aluminum based) in the "Z" or zeppelin rocket which had the blade and fired in groups of five vs the "D" or drachen which was fired in groups of four. Details remain fairly loose but getting close to being able to make a mock up of some sort.
Cheers,
William

[TomVrille]

Greetings william...

Although not actual technical specifications, there is a nice short description of Le Prieur rockets in Ray Sanger's book Nieuport Aircraft of World War One.

It is noted that Le Prieur rockets were tested on a number of aircraft types including the Spad and Sopwith Pup, but were mainly employed with the Nieuport 11s and 16s, hence their inclusion in the book.

Some details not covered in earlier posts are that the head was weighted with sand, and attached to the rocket body with paper or linen tape which appears to have been varnished. The stick was approximately 1.5m in length, made of square-section pine, and attached to the body with three lengths of white tape.

The installation on Nieuport aircraft is described in some detail, aided by a good detailed photo on page 40 illustrating the means of attaching the launch tubes to the interplane struts.

[Turnbuckle]

I'm not sure of the original dimensions, but these were made from commercial poster tubes with the heads made up from bits of fence-post turned on a lathe. they certainly look the part.




Rob

[William]

Hello Rob,
Thank you for posting the photos they are helpful. No hard data yet but extrapolating/guessing/making it up as I go along. I've got 2 meters overall length (published); remainder estimated by comparing to known dimensions in photos and drawings, 465mm for the length of the rocket itself,50mm for the od of the rocket, 75mm for the length of the cone, and 15mm for the diameter of the stick. Need to visit the local rocket shop and see what I can cobble together. Rocket science!
Regards,
William

[SCMc]

William,

If the quote in my previous post is correct, the stick is square, not round. When you wrote 15 mm diameter, was that the distance across flats, or across corners?

A 14 mm wide square stick would fit snugly in a 20 mm I.D. (internal diameter) tube, with only about 0.16 mm tolerance. A 10 mm wide stick would fit in a 15 mm I.D. tube with almost 1 mm tolerance. Do you know the specifications of the launch tubing?

Steve

[Sreiko]

It look like resemblant of the old Congreyev rockets...

[Sreiko]

In that time black gun powder was used as propellant and maybe this type of material was inside. That mean that max speed could be some 400 m/sec but hard to believe that this rocket with no stabilization and of small diameter could reach even half of that speed. One small regression- Soviet AA rockets Dvina and Neva used black gun powder cylinder as propellant and they reach supersonic speed...

Let me know what you find on this as I'm building the Pup as a school project in Dallas. I plan the rockets on it.
John