What's new
British Ordnance Collectors Network

This is a sample guest message. Register a free account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!

BDU-59 A/B LGTR, Bomb Dummy Unit 59 A/B Laser Guided Training Round

pzgr40

Well-Known Member
Premium Member
Cutaway model of a BDU-59 A/B LGTR (Bomb Dummy Unit 59 A/B Laser Guided Training Round), the practice version for the GBU-10 (2000 pound), GBU-12 (500 pound) en de GBU-16 (1000 pound) laser guided bombs. It gives a smoke signal upon impact to show where the training round has landed.
This is much safer and cheaper than the usage of live rounds and -very important these days- much more environmental friendly.
The GBU-12 –for which the BDU-59A/B is the practice version- can be found here:
http://www.bocn.co.uk/vbforum/threa...d-other-derivates-of-the-Mk-82-500Lb-bomb-USA

The LGTR (Pict01) consists of -from nose to tail- the following parts; The seeker, the electronics, the steering fins, the pneumatic steering section, the pressurized nitrogen bottle, the battery, the aircraft interface section, the suspension lug, and the smoke signal cartridge in the tail.
The seeker translates the light signal into an electric signal that serves the magnets which serve the pneumatic valves. These valves allow nitrogen from the nitrogen bottle into the cilinders so the pistons move up and down, moving the fins that steer the LGTR to the spot lit by the laser.
The LGTR body is made of aluminium pipe, the nose is a machined aluminium cast piece. The wings are steel made, the steering fins are aluminium made.

Before the training round is suspended from the bomb rack (Pict.04) the spring loaded pin with the disc is kept in lower position by a wingnut at the outside of the body of the round. When placed in the bomb rack the wing nut is removed as the bomb rack forces the pin inward. When the training round is released, the spring pushes the pin outward with force, pushing the training round away from the bomb rack. The disc also moves up and switches the roller contact to closed, starting up the electric circuit.
To the front of the white plastic disc one can observe the 9volt battery, wrapped in black tape.

Befor the LGTR is placed in the bomb rack the code switch is set between 1 and 12 (Pict.02). The laser aimer, -painting the target- is set to the same number between 1 and 12, so the LGTR seeker will react to that laser aimer signal only.

The nitrogen gas botle (picture 03) is closed by a diaphragm and is opened 3,1 seconds after release of the LGTR from the bomb rack by a hollow needle projected through the diaphragm by means of a small explosive piston. This will pressurize the entire pneumatic steering system, fixating the fins in neutral position when the magnetic powered valves are not served by a steering signal. Behind the nitrogen bottle one can see the battery , wrapped in black tape.
In front of the steel block one can observe the magnetic powered valves which regulate the nitrogen flow to the steering cylinders.
The pressure in the Nitrogen bottle is 3000 Psi.

A steel disc with a fixed firing pin (pict. 05) is placed in the tail end of the LGTR body, secured with four screws. The shellcase of the smoke cartridge is aluminium made, placed in a steel pipe that acts as a chamber for the shellcase as wel as an inertia weight. The assembly is placed in a white plastic tail piece. The base of the shallcase rests on a soft steel rimmed ring that keeps the firing cap of the shellcase away from the firing pin. Upon impact, the the shellcase with the pipe piece move forward caused by inertia , bending the rimmed ring, allowing the firing cap to move into the firing pin. This will ignte the black powder charge in the base of the shellcase, as well as the quickmatch which runs through the smoke charge (green), throwing out the burning snmoke composition to mark the place of impact.
As the smoke cartridge is placed in the airfield workshop just prior of the LGTR being placed in the bombrack, the white plastic tail piece is secured to the aluminium pipe with four wood screws for ease of assembly.

Data BDU-59A/B LGTR:
Length: 6,3 ft (1,9 mtr).
Diameter bomb body : 4 inch (102mm).
Wingspan aft wings : 19 inch (483mm).
Weight : 89 Pound (40,37 Kg).
CEP (Circular Error Probability) : 4 mtrs.

Regards, DJH
 

Attachments

  • 01 - BDU-59 A-B LGTR complete.JPG
    01 - BDU-59 A-B LGTR complete.JPG
    120 KB · Views: 54
  • 02 - BDU-59 A-B LGTR nose.jpg
    02 - BDU-59 A-B LGTR nose.jpg
    290.5 KB · Views: 44
  • 03 - BDU-59 A-B LGTR Nitrogen bottle, battery and  valves.jpg
    03 - BDU-59 A-B LGTR Nitrogen bottle, battery and valves.jpg
    314.7 KB · Views: 38
  • 04 - BDU-59 A-B LGTR arming switch.JPG
    04 - BDU-59 A-B LGTR arming switch.JPG
    283.4 KB · Views: 36
  • 05 - BDU-59 A-B LGTR smoke cartridge.jpg
    05 - BDU-59 A-B LGTR smoke cartridge.jpg
    290.5 KB · Views: 38
Last edited:
Top