jimoutofthebox":22cta7s8 said:
The N1 failure was not caused by the number of engines but rather the lack of quality control in design and at the factory. If you drop a bolt into a Falcon X turbo pump as they did on the N1 you will have the same result. If you drop a bolt into the current Falcon 9 turbo pump you loose one engine but you still get to orbit. The Soyus rocket has flown over 800 time with a excellent reliability and it has a total of 30 engines running at lift off.
An example of when I was working on the USAF Atlas E/F program it doesn’t take a large number of engines for QC to hurt you. The three failure examples occurred in 1980-1981 and caused three mission failures out of 5 flights in a row.
The first was when a seal on the turbo pump on RP1 side fortunately failed and flooded the turbo pump gear box causing more than 3 sigma low thrust. The result was that the booster engine cutoff went on backup (a timer) instead of by command further complicating things resulting in the sustainer engine burn time to take more than 45 seconds extra burn time. This would not have been bad except that the software of the satellite controlled its own separation and maneuvering after sustainer cutoff. The software (the idiot it was determined the 7g of acceleration it was reading on its accelerometer was wrong started separation 20 seconds after the nominal sustainer cutoff time. The satellite used up all its maneuvering fuel trying to reorient for it’s circularize orbit burn while plastered to the front of the Atlas. The resulting orbit the satellite eventually ended up in made the satellite unusable.
The second was someone forgot to reinstall the turbo pump oil drain plug on one of the booster engines. This caused the engine to fail (shut off because the turbo pump locked up) 3 seconds before the commanded booster engine shutdown. Since the Atlas uses three engines in a row two 186K pound force engines with the 70K sustainer in the center, a very large rotational torque was place on the atlas causing it to swing through 270 degrees horizontal in about 5 seconds before the two 2k pound attitude control engines could stabilize. Compounding the egg on everyone’s face was range safety started tracking the wrong item (the booster package and not the Atlas) and said everything was fine. I remember the callouts from range safety and telemetry giving very conflicting information: Rage Safety “Gone ballistic”, Telemetry “Thrust OK”. Fortunately the Atlas ended up going west out into the Pacific instead of east toward LA.
The third item was a complete engine failure at 3 seconds into flight of yet another booster turbo pump causing a very large explosion when it impacted the hillside just south of the pad.
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