View Full Version : 747 trivia
Has anyone got info on the following:
1. What's the reason for the elevator split on the 74, I looked up the SB a while back to no avail after seeing an early photo with no split.
2. I also spotted a "Elev Trim" guage (inop) on the back left of the center pedistal on a Polar Air -100 not sure of previous operator how was it used without appearing like an
elev position indicator.
3. And finally anyone know which operator's have the Fwd and/or Aft cargo coditoined air system (from pack #3) saw the drawing's but no line #'s.
cheer's
Don't know whether this can help u.
From my v v v vague memory, the split between inbd/outbd elevators in the 74 is subject of a v early SB. Maybe the with aerodynamic loading on the hori fin in flight, its curvature may change/bend and with the split a straight line may restore.
For the fwd/aft freight holds aircon, are u saying the B747-400F ?
Any ideas from fellow engineers ?
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Not much of an engineer
greaseytech
6th Dec 1999, 19:32
With reference to the split elevator, although I have never set foot onto a 74, so I cannot be sure about the accuracy, on F4's there was a split spoiler that was introduced aeons ago. The reason for this was that the single spoiler panels cracked inbetween the actuators. So to eliminate this problem they introduced split spoilers! So perhaps there is a similar reason for fitting split elevators on 74's. They say that the that the simple solutions are the best.
Ahhhhh.
The elevator split CCA referred is a slight offset where inbd and outbd elevators meet each other. They are separate panels powered by separate actuators from day one.
Any other inputs from all ?
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Not much of an engineer
I was replacing the insulation blanket's for the entire acon bay with a new type ,the job came with some SRM drawing's which indicated pack #3's conditioned air split after the water separator.I'm fairly sure if you look in R/H BLG WW (-400) you can see evidence of where the duct would pass through the bulkhead in the same position as the APU bleed air duct on the left,there was no indication of type.I'll try and find the photo of the elev befor the split was introduced, it was probably during testing that they changed it,what about the 76 split.
gas path
7th Dec 1999, 03:11
H721
Yep. your about right there.The split is to accomodate aerodynamic loads.When the a/c is flying the stab tends to twist and the inbd and outbd elevators fair.
If my memory serves me right its 4 inches at the trailing edge.
Are there that few of us ,I thought 3eng to 1,pilot was the ratio or are they on some other forum.