"Weighty" issue...

[David Jolly 877288]

I have been flying a DC-10-30 model which I have adjusted to get the weights correct for an MD-10. Based on several sources including Boeing, there is an issue screaming at me, and I'm guessing there's a simple answer.

Empty weight is published at 269,000 pounds. Max payload is 180k. The kicker is that max landing weight is 411,000, which is below the aircraft and payload weights with zero fuel aboard.What is with this max payload weight if it's seemingly impossible to fly (or, more correctly, land) with it?

 

I haven't run numbers on other birds, but suspect that I'll run into similar situations. Anyone know what I'm missing here?

Thanks,

Dave

[David Klain 874106]

Topic moved..not a real-world aviation issue but rather a request for [Mod - Happy Thoughts]istance with flight simulation software.

 

Dave

[tom van der elst]

I have been flying a DC-10-30 model which I have adjusted to get the weights correct for an MD-10. Based on several sources including Boeing, there is an issue screaming at me, and I'm guessing there's a simple answer.

Empty weight is published at 269,000 pounds. Max payload is 180k. The kicker is that max landing weight is 411,000, which is below the aircraft and payload weights with zero fuel aboard.What is with this max payload weight if it's seemingly impossible to fly (or, more correctly, land) with it?

 

I haven't run numbers on other birds, but suspect that I'll run into similar situations. Anyone know what I'm missing here?

Thanks,

Dave

 

what you are missing is that many planes can fly with

either full fuel or a full payload,but not with full fuel ánd a full payload.

[David Jolly 877288]

I guess the problem I see with the MD-10 numbers is that, with the 180,000 pound payload added to the published empty weight (I got the numbers from the Boeing website), the aircraft is above the maximum landing weight before adding an ounce of fuel.

 

Seems to make the max payload number seem impractical (or unusable), unless one is using the plane for a storage building. It's not really a problem with any simulated model, it's the real world numbers that aren't making sense to me. Perhaps it is simply a structural limit number which really isn't meant to be flown?

[tom van der elst]

well,

 

they give the maximum design taxi weight for the MD-10-10F as 443000 lbs in the following

table http://www.boeing.com/commercial/airports/acaps/dc10sec7.pdf

and that is backed up by this publication which gives 10.000

pounds less to the DC10-10 p[Mod - Happy Thoughts]enger model most MD10's are based on

which I can believe : http://www.boeing.com/commercial/airports/acaps/dc10sec2.pdf

 

also the operating empty weight is 240171 pounds for the DC10-10 so I imagine the MD10 will be

lighter as that has no p[Mod - Happy Thoughts]enger amenities in place.

 

so 269000+180000 = 449000 that means fully loaded will cost a measly 5000 pounds of payload

if I read correct.

But then again,we can safely say 240000 + 180000 = 420000 and that gives full payload below design limits,

and leaves ample room for fuel for a very short flight.

 

also here you find max landing weights differ per flap usage

Must be heavy ping pong balls since the MD10-10 has a MTOW of 440,000 Lbs, MLW 375,000 Lbs Flaps 50, 363,500 Lbs Flaps 35

 

(note the difference between the maximum ramp weight and maximum takeoff weight of 3000 pounds)

 

http://www.pprune.org/rumours-news/print-131661-fedex-md-10-mem-2.html

 

and again,do not forget the "payload weight* is often determined by the need to take fuel.

they'll take fuel first,then fill up space that is left with payload.

This is the reason p[Mod - Happy Thoughts]engers are sometimes bumped off flights,

it's not all because of overbooking,and with regards to freight and p[Mod - Happy Thoughts]engers

weight remains weight,if the cargo is selfloading or not.

 

 

hope that helps.

 

cheers

 

Tom.