According to some info I was reading, the 747-300 wing was slightly resdesigned to allow a Mach 0.85 cruise vs the 0.84 cruise for the -200.
Does that mean the -200 couldn’t achieve M0.85 in cruise ...at all? I’ve seen charts that had the -200 with a max cruise speed of M0.86. Im guessing this was achieved at very high power settings? So is the 0.84 vs 0.85 diiference simply what would be achieved at a normal cruise power setting for the -200/300 models?
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Re: 747-200 wing vs -300 wing
I am not sure the wing was redesigned. I know somewhere during the production run, about midway of the 300, the wing/body fairing was improved to what would be the 400 standard. Other than that, I don't think anything else was done, but I could be wrong. IIRC, the 747-200 and 300 both had the same econ cruise profile of .84 IMN, at least for the airline I worked for. The 300 was more aerodynamic because of he upper deck stretch and the area rule effect.
The 200 and 300 had the same MMO which was .92 IMN. To be honest, the 200 could do .86 without too much additional thrust. But, the "sweet spot" seemed to be .845, while the 300 tended to be .850 ish......
The 200 and 300 had the same MMO which was .92 IMN. To be honest, the 200 could do .86 without too much additional thrust. But, the "sweet spot" seemed to be .845, while the 300 tended to be .850 ish......
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- Florianopolis
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Re: 747-200 wing vs -300 wing
Did the longer upper deck on the -300 improve area ruling? Enough to add 0.01 M ?
Re: 747-200 wing vs -300 wing
Florianopolis wrote:Did the longer upper deck on the -300 improve area ruling? Enough to add 0.01 M ?
Yeah, that was it, mmo hit the nail on the head. If you look at the 748 F vs I, you'll see the gap there for the same reason.
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- RetiredWeasel
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Re: 747-200 wing vs -300 wing
I recall being dispatched for a late flight from I think LAX to NRT in a 747-200 at .86 in cruise. Can't remember if it was for curfew (that would have been really late) or pax connections but in reality if you do the math, at best you'd only save 13-15 mintues vs .84 for a 10 hour flight. Burn maybe have been a little more, but it was easily done and maybe saved on pax hotel bills or a divert because of airport closure.
Re: 747-200 wing vs -300 wing
Thank guys for the accurate information.
Also I'm chasing some info for the -200 with the R211-524D4 motors. At max GW (833,000), what would a typical initial cruise altitude be? I've read here and there FL290-310? Would that be at ISA temps? If it was say, ISA+20 etc, would you expect that to be lower?
If anyone has any info regarding this, again, it would be GREATLY appreciated!
Also I'm chasing some info for the -200 with the R211-524D4 motors. At max GW (833,000), what would a typical initial cruise altitude be? I've read here and there FL290-310? Would that be at ISA temps? If it was say, ISA+20 etc, would you expect that to be lower?
If anyone has any info regarding this, again, it would be GREATLY appreciated!
Re: 747-200 wing vs -300 wing
At MTOW, most of the 200s would do anywhere from 290-310 and that would be at ISA+15 to +20. Depending on the winds and environmental factors 290 might be the initial level off.
Re: 747-200 wing vs -300 wing
The747-200 wing was the same although fairings might be different. Long Range Cruise at high weight was M.85-.86
Re: 747-200 wing vs -300 wing
113312 wrote:The747-200 wing was the same although fairings might be different. Long Range Cruise at high weight was M.85-.86
OK interesting. Thank you once again everybody for the assistance..
Re: 747-200 wing vs -300 wing
You can actually see the improved wing-body leading edge fairings in photos on this site. It's subtle, but visible.
It's worth noting that the last few 747-200F's off the line received the improved fairings.
ANA 742F's had them.
JAL did not.
Visually, the improved part has an appearance of the root of the leading edge extending through the fairing and into the fuselage, while the old one looks like the straight edge wing got bolted onto the flat edge body.
I won't charge any commission for that horrible explanation....
It's worth noting that the last few 747-200F's off the line received the improved fairings.
ANA 742F's had them.
JAL did not.
Visually, the improved part has an appearance of the root of the leading edge extending through the fairing and into the fuselage, while the old one looks like the straight edge wing got bolted onto the flat edge body.
I won't charge any commission for that horrible explanation....
Re: 747-200 wing vs -300 wing
The 747-200 and -300 wings have common OMLs.
This is some information that Boeing published in an AIAA technical paper; It shows that the extended upper hump of the 747-300 and 747-400 improves the transonic area ruling of the aircraft. This increases the drag divergence Mach number of the aircraft.
The 747-400 wing/body fairing includes a wing root strake. This is designed to mitigate the formation of a leading root vortex (necklace vortex), caused by the fuselage boundary layer separating in the adverse pressure gradient ahead of the wing leading edge.
This is some information that Boeing published in an AIAA technical paper; It shows that the extended upper hump of the 747-300 and 747-400 improves the transonic area ruling of the aircraft. This increases the drag divergence Mach number of the aircraft.
The 747-400 wing/body fairing includes a wing root strake. This is designed to mitigate the formation of a leading root vortex (necklace vortex), caused by the fuselage boundary layer separating in the adverse pressure gradient ahead of the wing leading edge.
Re: 747-200 wing vs -300 wing
We had serious issues on our -300's at SAA, with the inboard engines stalling and throwing fan blades due to that extended 'hump'. P&W sent out a team to investigate the problem but I don't remember what they came up with to cure the problem.
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