BA
Topic Author
Posts: 10134
Joined: Fri May 19, 2000 11:06 am

Max Payload On 747-400ERF Lower Than On 747-400F?

Sun Oct 22, 2006 4:03 am

I was looking at this 747 Freighter brochure from the 2005 Paris Air Show and it struck my attention that with the higher MZFW option, the 747-400ERF has slightly lower structural payload than the 747-400F, 272,600 lb versus 273,300 lb.

http://www.boeing.com/news/feature/p...ts/bca_pdf/specs/747_Freighter.pdf

Why is this the case?

Other then that, the specifications of the 747-400F and the 747-400ERF with the higher MZFW option appear to be identical. The range for both is listed as 2,815 nm, the MZFW for both is listed as 635,000 lb and the MTOW for both is listed as 811,000 lb.

Does this mean the advantage of the 747-400ERF over the 747-400F is pretty much only if the higher MZFW option is not selected? Makes you wonder why it is offered on the 747-400ERF to begin with.

Any feedback would be greatly appreciated.
"Generosity is giving more than you can, and pride is taking less than you need." - Khalil Gibran
 
744rules
Posts: 391
Joined: Sat Mar 30, 2002 3:34 am

RE: Max Payload On 747-400ERF Lower Than On 747-400F?

Sun Oct 22, 2006 6:09 pm

don't know about the -400erf, but when you have the increased zfw on the -400 ( between 276000 and 288000) you're max tow is decreased. This means it's either max range or max payload.
 
PolymerPlane
Posts: 832
Joined: Thu May 11, 2006 1:12 am

RE: Max Payload On 747-400ERF Lower Than On 747-400F?

Mon Oct 23, 2006 10:07 am

I am not an expert, but IIRC, The difference between 744ERF and 744F is basically increase in MTOW and additional fuel tanks. I think this modification makes the 744ERF has slightly higher OEW. For the optional MZFW, the MTOW is basically limited to the same weight. Thus, your structural payload is lower on ERF.

BTW I still can't understand why any company would buy 744ERF with the optional MZFW. You basically do not need higher OEW from additional fuel tanks and structural modifications, since your maximum range is only 2800 nm anyway, and you don't use the higher TOW on 744ERF.

Cheers,
PP
One day there will be 100% polymer plane
 
Rj111
Posts: 3007
Joined: Wed Sep 08, 2004 9:02 am

RE: Max Payload On 747-400ERF Lower Than On 747-400F?

Mon Oct 23, 2006 8:33 pm

The 744ERF has the same max payload 112t or 123t (optional) as the 744F. Just it has a higher takeoff weight thus can fill up the tanks more when that payload is added. The tanks are the same size as the 744F and 744, but fuel is weight restriced at the top payloads.

Quoting 744rules (Reply 1):
don't know about the -400erf, but when you have the increased zfw on the -400 ( between 276000 and 288000) you're max tow is decreased. This means it's either max range or max payload.

The MTOW isn't decreased - it's increased. Compared to the 112t MSP version the max useable fuel capacity is +10t and the MZFW is increased +11t but the MTOW is only inceased +9t. So the MTOW is the limiting factor depending how far you're flying it. But then again, MTOW is always the limiting factor, just seems to be more pronounced on the 123t version. These are all paper ratings though.

At least that's how i understand it.   

Source http://www.boeing.com/commercial/airports/acaps/7474sec2.pdf

[Edited 2006-10-23 13:40:41]
 
747Loadmaster
Posts: 59
Joined: Mon Oct 25, 2004 9:42 am

RE: Max Payload On 747-400ERF Lower Than On 747-400F?

Mon Oct 23, 2006 11:45 pm

Quoting 744rules (Reply 1):
don't know about the -400erf, but when you have the increased zfw on the -400 ( between 276000 and 288000) you're max tow is decreased. This means it's either max range or max payload.

That is correct, if you use increased ZFW, MTW comes down.
I will post the exact amount tomorrow

Who is online

Users browsing this forum: No registered users and 12 guests