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747 Converted Freighter Question  
User currently offline413X3 From United States of America, joined Jul 2008, 1983 posts, RR: 0
Posted (4 years 5 months 4 weeks 13 hours ago) and read 4196 times:

When converting a 747 to a freighter aircraft, why can't they add a nose cargo door? It seems that's the only downside to the type, so why isn't it possible?

Thanks

18 replies: All unread, jump to last
 
User currently offlinelotsamiles From United States of America, joined May 2005, 323 posts, RR: 0
Reply 1, posted (4 years 5 months 4 weeks 12 hours ago) and read 4133 times:

I would imagine it is possible but the cost would be outrageous. Given that only a small percentage of 747F loads require the nose door it is likely not worth the extra cost for the benefit gained (including the quicker turn time for loading from both nose and SCD).

User currently offlineStitch From United States of America, joined Jul 2005, 30914 posts, RR: 87
Reply 2, posted (4 years 5 months 4 weeks 12 hours ago) and read 4098 times:
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Quoting 413X3 (Thread starter):
When converting a 747 to a freighter aircraft, why can't they add a nose cargo door? It seems that's the only downside to the type, so why isn't it possible?

Dedicated 747 freighter operators do use the nose door on a regular basis, so despite some a.net commentary that it's a useless feature, Boeing wouldn't offer it as a standard feature if operators didn't want it. And if operators did not want a nose door, they would not accept the extra weight and complexity it brings and would have demanded Boeing make it optional.

Therefore, if it was only a "trivial" modification to add it to passenger 747-400s, I would expect it would be at least an option for conversion kits. That they don't, makes me believe it is not a trivial thing. I would not be surprised if the lack of such conversions is to do with structural issues. A dedicated freighter might have reinforcements and such to allow for that feature, for example.


User currently offlineTb727 From United States of America, joined Jun 2005, 1588 posts, RR: 9
Reply 3, posted (4 years 5 months 4 weeks 12 hours ago) and read 4060 times:

I think also that the attractiveness a few years back to operating the 747 Classics as converted freighters was that you can do it relatively cheap. Adding the engineering and the costs to cutting the nose off an airplane wouldn't be very attractive if I was buying and converting them to freighters.


Too lazy to work, too scared to steal!
User currently offlineairbuseric From Netherlands, joined Jan 2005, 4268 posts, RR: 51
Reply 4, posted (4 years 5 months 4 weeks 12 hours ago) and read 4045 times:

Quoting Stitch (Reply 2):
Dedicated 747 freighter operators do use the nose door on a regular basis, so despite some a.net commentary that it's a useless feature,

We turn around a B747-400F with nose and sidedoor, simultaneous lowerdeck & maindeck (un)loading, with 4 highloaders in use, in 45 minutes... Only refuelling might take a bit longer then.

Usual groudtimes for a B747-freigher is 3 hours though.



"The whole world steps aside for the man who knows where he is going"
User currently offlinelotsamiles From United States of America, joined May 2005, 323 posts, RR: 0
Reply 5, posted (4 years 5 months 4 weeks 11 hours ago) and read 3970 times:

No question the nose door is a great feature that allows loading of long items and also loading with a faster turn around time. The question is what would an airline taking a conversion be willing to pay for that, or a leasing company looking to recover their conversion investment with incremental lease revenue. Since the 747 P2F conversion is over $20M without the nose door I would put a WAG out there that the nose door would be easily over $5M by itself and probably closer to $10M, especially if done by Boeing. That extra cost would be a significant factor in the financial model.

User currently offlinewn700driver From , joined Dec 1969, posts, RR:
Reply 6, posted (4 years 5 months 4 weeks 11 hours ago) and read 3939 times:

Oddly enough, the first tranche of 741s had the "option" of a nose cargo door built into the frames, specifically to facilitate this conversion. I think it was a case of Boeing not being sure that the plane would sell at all as a PAX , and so they just engineered into the design. IIRC, the subcontractor assy lead times did not give them the option to dither about it, so they just built in the structural re-inforcement (but not the actual door) right into the frame, so they could go out as freighters instead if need be.

When the success of the PAX became more obvious, this "option" was deleted. Anyway, I could have a detail or two wrong, so if someone here knows better (ahem. . . tdscanuck,   ), please feel free to chime in!


User currently offline413X3 From United States of America, joined Jul 2008, 1983 posts, RR: 0
Reply 7, posted (4 years 5 months 4 weeks 9 hours ago) and read 3892 times:

With all the 747-400s sitting around now, I am surprised companies like Atlas/Polar, World, Cargolux, Lufthansa, etc. who all take odd loads, haven't picked up converted freighters and added a nose door.

User currently offlineB777LRF From Luxembourg, joined Nov 2008, 1334 posts, RR: 3
Reply 8, posted (4 years 5 months 4 weeks 9 hours ago) and read 3882 times:

Besides the sheer cost of including a nose-door on a conversion, which are outrageous, you're also adding a lot of weight to the airframe which will have an adverse effect on the economy.

And it's not just a question of chopping the nose of and bolting a couple of actuator arms on. There's a lot of structrual reinforcement to be done as well, which all adds to the weight, cost and complexity.

We rarely use the nose-door on the -400Fs flying for us. Yes, you can turn the bird around faster if you do, but at the cost of using extra equipment and manpower. We've got enough room in the schedule not to need the shorter turn-around, so why bother?

Should be noted that we only fly bog standard loads; it's specialists like Cargolux who messes around with America Cup yachts and whatnot, with masts almost as long as the main-deck, who really needs that door. Good mate of mine is very senior with Cargolux and he positively love the nose-door, and wastes not time pointing out the magnitude of our stupidity for not using it more.

Horse for courses and all that.



From receips and radials over straight pipes to big fans - been there, done that, got the hearing defects to prove
User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 9, posted (4 years 5 months 4 weeks 3 hours ago) and read 3781 times:

Quoting 413X3 (Thread starter):
When converting a 747 to a freighter aircraft, why can't they add a nose cargo door?

If "they" is the conversion folks, it's because nobody has done the SB or STC to do so.

If "they" are the SB/STC authors, it's because it's not economically viable.

Quoting 413X3 (Thread starter):
It seems that's the only downside to the type, so why isn't it possible?

It is possible; if you can turn a 747 passenger into a 747 LCF, you can certainly put on a nose door (the nose door is trivial compared to the swinging tail on the LCF). It just doesn't pay off as a economic proposition for normal freighter conversion.

Tom.


User currently offlinekiwiandrew From New Zealand, joined Jun 2005, 8556 posts, RR: 13
Reply 10, posted (4 years 5 months 4 weeks 2 hours ago) and read 3772 times:
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Quoting wn700driver (Reply 6):
Oddly enough, the first tranche of 741s had the "option" of a nose cargo door built into the frames, specifically to facilitate this conversion. I think it was a case of Boeing not being sure that the plane would sell at all as a PAX

I recall reading somewhere ( and I have no idea whether this was actually true , or just an urban myth ) that Boeing expected the 747 to have a relatively limited service life as a pax aircraft because in a few years everyone would be buying the supersonic Boeing 2707 and nobody would want to fly on such a 'slow' aircraft as the 747 . So in order to persuade airlines that there was less risk of being very quickly stuck with an obsolete aircraft they tried to convince them that when pax no longer wanted slow planes freight would still be fine at subsonic speeds .



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User currently offlineStarlionblue From Greenland, joined Feb 2004, 17030 posts, RR: 67
Reply 11, posted (4 years 5 months 4 weeks 2 hours ago) and read 3763 times:

kiwiandrew, that is definitely not a myth. The 747 was definitely seen as being in the last generation of subsonic long-range airliners. Designers on the 747 project were told to hang in there, as there might be space later on the 2707.

In fact, the defining feature of the 747, the hump, is a cargo carrying adaptation. By moving the flight deck above the main deck, they could load cargo on the whole main deck. Together with the nose door, that made for easy through loading. Compare with aircraft like the Super Guppy that have to hinge the nose out of the way.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineavioniker From United States of America, joined Dec 2001, 1109 posts, RR: 11
Reply 12, posted (4 years 5 months 4 weeks ago) and read 3728 times:

You are all missing one very strong economic truth concerning the 747F.
The nose loader is severely height limited. Long loads are great but one big advantage to the side door is the tall loads the plane can take compared to any other freighter.
You can't load a Huey helicopter in a nose door. It has to go in the side, for instance.
Not an opinion, been there, done that (too many times).



One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
User currently offlineAirTran737 From United States of America, joined Apr 2004, 3704 posts, RR: 12
Reply 13, posted (4 years 5 months 3 weeks 6 days 22 hours ago) and read 3692 times:
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Quoting avioniker (Reply 12):

Bingo. You can't put anything over 96" tall through the nose and all the way to the Echo positions. Foxtrot positions to the Tango position can take a 120" pallet



Nice Trip Report!!! Great Pics, thanks for posting!!!! B747Forever
User currently online747classic From Netherlands, joined Aug 2009, 2124 posts, RR: 14
Reply 14, posted (4 years 5 months 3 weeks 6 days 15 hours ago) and read 3593 times:

First some history :

The first 747 freighter (a Lufthansa 747-230F, line number 168) was certificated on March 7, 1972.
It was only equipped with the nose cargo door and remained for two years the only freighter, because of the economic downturn in the beginning of the seventies. Boeing began to worry that the $54.2 million developement costs of the -200F had been money wasted, but after a few years the -200F became a steady seller, with 73 delivered, before production changed to the 747-400F.

Sales of the 747-200F were boosted by the the $15 million development of the an optional side cargo door, that could take 10 foot-high loads, as opposed to an 8-foot limit through the nose, because of the flightdeck floor. The first 747-200F with the side cargo door was line number 242 for Seaboard World.

Before the introduction of the side cargo door , Boeing offered for a very limited time a nose door conversion, but no airline wanted this conversion, because the predicted supersonic revolution never took place and the airlines needed their passenger 747's. Also the weight/ engine power combination of these early 747's was not suited for cargo conversions. Conseq. no master change was designed by Boeing.

As mentioned before in several replies from others, no airline is interested in a nose door addition of a -BCF conversion seen the huge extra modification costs (incl. certification), the added weight and the relative limited usage of nose door loading. These extra costs have to be earned back in the remaining lifespan of the aircraft, after the modification (in most business cases approx 10 years). It's technical possible, but economically not viable.


To cater for over-sized, very long cargo loads, most cargo airlines have a mix of dedicated 747 freighters and -BCF aircraft.
If the need arises for transportation of some special sized loads, the dedicated freighter can be (re-)scheduled for that particular stretch.

[Edited 2010-03-09 09:13:51]


Operating a twin over the ocean, you're always one engine failure from a total emergency.
User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 15, posted (4 years 5 months 3 weeks 6 days 12 hours ago) and read 3556 times:

Quoting kiwiandrew (Reply 10):
I recall reading somewhere ( and I have no idea whether this was actually true , or just an urban myth ) that Boeing expected the 747 to have a relatively limited service life as a pax aircraft because in a few years everyone would be buying the supersonic Boeing 2707 and nobody would want to fly on such a 'slow' aircraft as the 747 .

It's true...it's documented in several places, but one of the more recent and reliable is Joe Sutter (747 Chief Engineer's) book.

Tom.


User currently offline413X3 From United States of America, joined Jul 2008, 1983 posts, RR: 0
Reply 16, posted (4 years 5 months 3 weeks 6 days 10 hours ago) and read 3532 times:

Thank you all for the info. It's a shame the 747s numbers are dwindling. I wonder if fitting one next gen engine on each wing to half fuel costs would be beneficial in the future! The design of the nose door is perfect for those special cargo carriers

User currently offlineStarlionblue From Greenland, joined Feb 2004, 17030 posts, RR: 67
Reply 17, posted (4 years 5 months 3 weeks 6 days 8 hours ago) and read 3502 times:

Quoting 413X3 (Reply 16):
I wonder if fitting one next gen engine on each wing to half fuel costs would be beneficial in the future!

You mean making it a two holer? There are no engines currently in production or on the horizon that are powerful enough for that. Also this would in no way halve fuel consumption.

Quoting 413X3 (Reply 16):
The design of the nose door is perfect for those special cargo carriers

Yes it is. However let's not forget the Antonov 124 and 225. They might not be as efficient fuel wise, but they are perfect for outsize loads.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently online747classic From Netherlands, joined Aug 2009, 2124 posts, RR: 14
Reply 18, posted (4 years 5 months 3 weeks 5 days 20 hours ago) and read 3409 times:

Here is a production photo of the third 747-8F nose section.(section 41)
Clearly visible are the very heavy reinforcements of the fuselage for the hinges of the nose cargo door.
IMO very expensive to modify the original nose section afterwards with a nose door. (-BCF)

http://farm4.static.flickr.com/3095/3503471710_39fa39848f_b.jpg



Operating a twin over the ocean, you're always one engine failure from a total emergency.
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