On cannons:
David
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Cheetah E 842 had a gunpack that consisted of the ammobox and the two Defa cannons. The ammobox is the big square box and the two side panels are the gundoors. They were used for access to the cannons. If that is what you talk about.
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The original fwd facing scoop was a single half round unit. It was modified to dual square intakes to accommodate the 412 pylon if my memory is still intact.
On the D an E the cannons were fixed onto the gunpack itself. On the C the cannons were fixed to the airframe with the ammobox as an independent unit.
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The Cheetah were never too good with guns. The F1 was far more superior with that. But don't let them know I admitted it. Calibration was done by shims on the cannon itself. There was a sight fitted into the barrel and aligned to a board in front. The avionics boffins were aligning the systems with that and we the cannons to that. So in the end the cannons and the avion systems were aligned. But the Cheetah cannons were firing in a flat "infinity" sign shape so the accuracy was not the very best.
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Once me and a very good friend reloaded Cheetah E cannons at LBWG in under 10min. When the pilot got out of the cockpit to inspect the aircraft the gunpack was on it's way back
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The Cheetah 30mm (round) was local and available in HE, HEI, SAPHEI and of course the practice round.
Kobus
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Cheetah D & E had the same gunpack as in the Mirage III. I have photos. The whole pack dropped out, barrels stayed behind. You could also swap the gun/ammo pack for a fueltank.
David
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Never seen it done though, but we did remove a lot of gunpacks for access to a fuel panel inside the gunbay that sprung a leak. Always thought why that freaken panel was built at that location.
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David
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When removing the gunpack, one first had to unlock and pull the barrels forward to remove them from the cannons. Then 4 bolts were loosened and the gunpack was lowered with a cable pulley system and placed on the red gunpack stand, the yellow Steinbuck 2as used to raise and lower equipment and bombs. The barrels were then pulled backwards out of the aircraft and replaced in the cannons for the loading. The ammunition was stored inside the centre between the two cannons. The cannons were hand cocked and took some practice to master a smooth cocking action. Many old armourers today complain of tennis elbows today (me being one)
. Here on the picture we have on the left Piet du Toit (RIP) and on the right Blakie Swart (RIP). The guy in centre I cant remember.
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Yes the reverse to install. If the cannons were cycled with loading, there was a chance that the pressure ring on the drum can be dislodged
That is now without the barrels. If that happens the pressure is escaping at the barrel contact point and the gundoor is lost in flight. The cannon will not cycle and the recoxking cartridge will fire. But as soon as the next one fires in that location, the cannon will not cycle again and because there is no more re-arm cartridge the cannon will jam.
That is why the SAAF looked into modifying the Defa to take more re-arm carts. It was done but never used in Cheetah.
de Beer
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The barrel need to be fitted to prevent the sealing rings to dislodge from the front of the drum in the canon. When the round is fired the ring move slightly forward and push against the face of the barrel to form the seal and prevent pressure lost
Q: Looks like blue training rounds
David
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That is correct and it looks like the tips were dipped in yellow which means it is at Lbwg for AA firing on the flag. Red, yellow, blue and green were the colours for flag firing.