Ghenea pedestal sight

The Ghenea pedestal sight was a telescope with goniometer invented by the Romanian commander Toma Ghenea in two different models designed for field howitzers with rigid or spring trail spade, and for quick-firing field guns. It was tested in January 1908 at the artillery proving ground of Dadilov (Dobrudja). A gun, placed on a rough ground, where only the point of the spade could get in, fired 20 rounds at a range of 4000 m, laying after every round in 65 seconds. The outcome was judged excellent, since the sight enabled to carry out quickly and surely the little corrections that the unfavourable firing conditions required after every shot. Therefore both the model were adopted by the Romanian Army.

The model designed for the quick-firing field guns enabled a quick and sure shift from a range to another, as required by the progressive fire, and the execution of the indirect laying at lateral auxiliary marks, even above wheels and shield. It allowed the gun layer to correct the range also during the relaying of the gun, while this was not possible with ordinary sights. However the manufacture of the mechanism of this sight was judged very complex and delicate.

Ghenea pedestal sight for quick-firing field guns. It was composed by a pedestal H H' V, carrying at the top a telescope. It could be shortened or lengthened, and could rotate 360° around the gun. The pedestal was mounted on a transverse horizontal pivot, attached to the block A, that was joined to the left side of the cradle by means of the support B, and the bolt N, parallel to the gun. The uninterrupted screw M enabled the block A to swing at right angle to the cradle. The air level m indicated the extent of that movement, and compensate the difference of level of the wheels.

The drum of the angles of sight t was attached to the pedestal by means of the arm d, while the elevating drum i, parallel to it, by means of the sleeve h'. Rotating the drum i, the layer could give the exact elevation up to 6400 m. Rotating the drum T, the pedestal s swung according with the size of the angle of sight, independently of the chosen elevation. The angle of sight was expressed in millièmes. The circular case P contained the elevation air level u, parallel to the arm d and at right angle to the rod H. The cover Q and the rod H' could rotate 360° around to case P and the rod H. The rotation could by obtained both turning the direction drum y', and working directly on the covers Q and Q'. The extent of the rotation could be read on the division placed on the side of the case; every line of the division corresponded to 1/1000 of the radius, the entire circumference being divided into 64 parts. The case P was the goniometer for indirect laying. The shifting of the cover Q as regards the cover Q' and the case P could be read on the division placed on the side of the case; every line of the division corresponded to 1/1000 of the radius, that was the 1/100 of the subdivision of the goniometer. Every laying angle expressed in millièmes could be easily obtained by means of this double rotation, thousands and hundreds being read on the goniometer, tens and units on the drum.

Acting on the bar V, inserted into the bar H', the pedestal could be shortened or lengthened. The height of line of sight was 1265 mm, when the pedestal was fully lowered, and 1555 mm, when it was raised at the utmost. In order to aim above the wheels and the shield an extension bar could be inserted to raise the line of sight up to 1855 mm. In this case the aimer pointed the gun standing upon his seat. During the march, the bar V, with the telescope Z on the top, was kept into the bracket box, and was mounted only when the gun was in awaiting position.

The telescope Z was arranged on the arm V so that it could be raised and lowered to keep count of the angle of sight or aim at an auxiliary mark, keeping the arm V vertically. In this way it was possible to lay without changing the position of the sight.

Ghenea pedestal sight for not quick-firing field howitzers. It was composed by a pedestal, carrying at the top a telescope. It could be shortened or lengthened, and could rotate 360° around the gun. The pedestal was mounted on a transverse horizontal pivot, attached to the base of the elevating gear, and through it to the gun. The elevating gear had an air level to compensate the difference of level of the wheels. A goniometer was added for indirect laying.

On the whole it was very similar to the model designed for the quick-firing guns, but was arranged so that it could be removed during the firing, in order to prevent that a precision tool like this was damaged by the shock peculiar of the not quick-firing artillery.

SOURCES :

- G. “Alzo Ghenea con goniometro”, Rivista di Artiglieria e Genio, 20/4 (1903), p.448;

- “Hausse a goniomètre Ghenea pour canons et obusier de campagne” : Supplement à la Revue Militaire Suisse. 48/6 (Juin 1903).

Ghenea pedestal sight for QF guns – left side	Drum of the angles of sight and elevating drum