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Author Topic: [ok] MD-88 range  (Read 1793 times)

Offline meiru

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[ok] MD-88 range
« on: January 28, 2014, 08:50:17 PM »
the MD-80 was first sold as MD-81 with JT8D-209's, one year later they installed JT8D-217's, JT8D-217A's or JT8D-217C's and increased the MTOW (Swissair did get it's last MD-81 with JT8D-217's by the way). The version with increased MTOW was named MD-82. Again 4 years later, they also offered the JT8D-219 (also for the MD-82) and increased the MTOW again. And then they installed a few new things and called it MD-88.

Now, it's very difficult to understand it, I know... so now here's what you can see from the FAA certification (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/eaa27d3270d91fe2862577dd006a94cc/$FILE/A6WE%20Rev%2028.pdf)

the 81 had a MTOW of 142000 lbs, and had the 209, 217, 217A, 217C and 219 installed (the 217 was installed on new aircrafts, the 217A, C and 219... as far as I found out, has been installed only later on 81s). the 81 had a total of 41765 lbs of fuel

the 82 had a MTOW of 147000 or 149500 lbs and had also the 209, 217, 217A, 217C and 219 engines, but I don't think the 209 has been chosen for any new aircraft... the 82 had the same tank system like the 81 but optional also an additional fuel tank like the 83 with 4112 lbs additional fuel giving a total of 49904 lbs

then the 83... had an MTOW of 149500 or 160000 lbs and was also offered with all engine types. But I think only the 217C and 219 have been sold ... but I'm not sure there. But having a high MTOW with the 209 wouldn't make sense, so I think we can assume that.
Now, the 83 had normally a 49904 lbs fuel tank system or a 55849 lbs fuel tank system. During conversions these auxiliary tanks could also been removed and thus reducing the fuel amount to 41765 lbs.

now the 87 was special... because it was shorter. it had a MTOW of 125000 or 149500 lbs and was offered with 217A, 217C and 219 only. it was available with a 41756 lbs tank, a 47351 lbs tank or even a 49895 lbs tank (ranges have to be calculated)

the 88 was offered also only with 217A, 217C and 219 engines with a MTOW of 149500 or 160000 lbs. and the same fuel system the 83 had!

... and (that's in the same FAA document) the MD-90...

offered with V2525-D5 and V2528-D5 engines and 160500, 166000 or 168000 lbs MTOW with a 41772 lbs or 45861 lbs fuel tank

-- in this document you can also find a lot of DC-9 infos

and... also -> the conversions between the different MD-80 models had some limitations... I don't know how you would implement those, but if an 81 (e.g.) had to be converted to an 83 with a much higher MTOW, it could cost a little bit more than converting an 82 to 83 with the same MTOW

I hope this info was good enough... I don't think it can be bether than FAA certification info
« Last Edit: February 12, 2014, 06:44:27 PM by sami »

Offline Sami

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Re: MD-88 range
« Reply #1 on: January 28, 2014, 08:55:45 PM »
So what's the actual bug here?

Ranges & data for all models should be from docs available at Boeing's site.

Offline meiru

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Re: MD-88 range
« Reply #2 on: January 28, 2014, 09:06:22 PM »
So what's the actual bug here?

Ranges & data for all models should be from docs available at Boeing's site.

Boeings page is not correct!!!

If the FAA says, that the model has been certified for those values! Then that's the the values you should use. Not what Boeing tells you about an McDonnell Douglas aircraft they wanted to get of the market as soon as possible!

And the MD-90-30ER ... is an ER because of the higher MTOW, the additional fuel tank is a second option to increase the range that was offered.

I think you should look at the fuel capacity and then calculate new and correct values for the 80 and 90's from what you have and from the fuel tanks available.

Offline Sami

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Re: MD-88 range
« Reply #3 on: January 28, 2014, 09:11:29 PM »
Still, what is the bug compared to what data we have now in the system? Really wouldn't like to start going through all MD-80 series values one by one, so please be more specific what should be changed.......

(+ weight unit used is kg)

(also, conversions between models isn't possible as you may know .. ie. cannot convert MD-81 into 83 etc in the game)

Offline meiru

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Re: MD-88 range
« Reply #4 on: January 28, 2014, 09:12:46 PM »
ok... give me some minutes and I'll post the list here

Offline meiru

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Re: MD-88 range
« Reply #5 on: January 28, 2014, 09:56:40 PM »
it needs still some adjustment and some discussion on how you want to simulate it... it's not that easy... but, some numbers

81

with 209
64 326 kg (Standard)  19 071 kg   Payload vs. range  1560 NM   Range map  3 370 kg / hr 

with 217 (one year later)
64 326 kg (Standard)  19 071 kg   Payload vs. range  1600 NM   ... 3 300 kg / hr ??


82

with 209 (possible, but I would drop it)

with 217
66 591 kg (Standard)  19 932 kg   Payload vs. range  2080 NM   Range map  3 440 kg / hr 

67 723 kg (+1.2 tn)   19 932 kg   Payload vs. range  2500 NM   Range map  3 480 kg / hr ?? 

with 217A also possible -> little difference in performance
with 217C also possible -> little difference in performance

83

with 209, 217, 217A -> possible, but maybe you can drop them because you sell them as 82s in the game

with 217C -> little difference in performance

with 219

67 723 kg (Standard)  19 932 kg   Payload vs. range  2500 NM   Range map  3 500 kg / hr 

72 480 kg (+4.7 tn)   19 932 kg   Payload vs. range  3050 NM  ?? ... 3600 kg / hr ??
  (not more payload, but more fuel possible)

87

with 217C

63 503 kg (Standard)  17 566 kg   Payload vs. range  2480 NM   Range map  3 170 kg / hr
 ... three types of fuel tank available, didn't calculate it


88

217A, 217C also possible, but you can drop it, and sell those as 83s in your game

with 219

66 591 kg (Standard)  19 932 kg   Payload vs. range  2130 NM   Range map  3 260 kg / hr 

67 723 kg (+1.2 tn)   19 932 kg   Payload vs. range  2550 NM   Range map  3 300 kg / hr ?? 

72 480 kg (+4.7 tn)   19 932 kg   Payload vs. range  3100 NM  ?? ... 3350 kg / hr ??
    ... 3 types of tank available ... the largest is only documented in the FAA certifications, so I have to guess the range...


md-90

72 700 kg (Standard)  18 973 kg   Payload vs. range  2000 NM   Range map  2 640 kg / hr 

md-90 er

76 204 kg (Standard)  19 880 kg   Payload vs. range  2390 NM   Range map  2 650 kg / hr 

V2525-D5
also V2528-D5 available ... don't know how to simulate the 595 gallon tank on the er

... because you don't always take the numbers, but add a "simulation"-factor, it's hard for me to say how the exact numbers have to be... but it's something like that... we can discuss this further of course

Offline meiru

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Re: MD-88 range
« Reply #6 on: January 28, 2014, 10:05:18 PM »
if in the future it would still not be possible to convert from 81 to 82 or 82 to 88 ... then I would make all those models simply an 80 ... and then create sub-types of the 80 ... (if that would allow a conversion later) ... same for the 90

Offline meiru

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Re: MD-88 range
« Reply #7 on: January 28, 2014, 10:09:08 PM »
the easiest you can do for now (the absolute minimum) is to add a second 88 subversion with the same range the 83 has (maybe a little longer) ...

there were even longer ranges possible... but if we forget everything and for the moment concentrate on just one thing, then this would be the second 88 version (the long range version with the higher MTOW)

or if you want one table, easy numbers, directly from McDonnell Douglas

http://airchive.com/html/memorabilia/mcdonnell-douglas-aircraft-history-sales-brochures-and-memorabilia/md-80-sales-brochure/550
« Last Edit: January 28, 2014, 10:27:53 PM by meiru »

Offline Sami

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Re: MD-88 range
« Reply #8 on: February 12, 2014, 12:14:10 PM »
Really still rather unclear what I should actually change .. I checked a few random weights from the tables quoted above and AWS data is already correct (checked -81, -87, -88), didn't find info on the additional weight variants though?

So is this report about missing engines or what actually? I assume yes, since each MD series have only 1 engine variant in AWS. But was there anything else? (as already mentioned the conversions between models aren't possible)


(And also, fuel usage in AWS is not inserted by one value "kg/hr", it's much more complicated/realistic but I assume you know this, and not sure if this was part of the report anyhow as the copypaste above is so unclear. Same for payload and range - it is not a single value, but actual payload vs. range chart. But the range data is already taken out from Boeing's (originally McDD's) docs and should be correct like already mentioned, since the weights seemed to be correct too .....)


edit: so engines are now as follows (?):

McDonnell Douglas MD-81    2x Pratt & Whitney JT8D-209
McDonnell Douglas MD-81    2x Pratt & Whitney JT8D-217
McDonnell Douglas MD-82    2x Pratt & Whitney JT8D-217
McDonnell Douglas MD-82    2x Pratt & Whitney JT8D-217A
McDonnell Douglas MD-82    2x Pratt & Whitney JT8D-217C
McDonnell Douglas MD-83    2x Pratt & Whitney JT8D-217C
McDonnell Douglas MD-83    2x Pratt & Whitney JT8D-219
McDonnell Douglas MD-87    2x Pratt & Whitney JT8D-217C
McDonnell Douglas MD-88    2x Pratt & Whitney JT8D-219

Also for MD-90 the V2528-D5 is added

For M81 the -217 appears 1 yr after first model is available, for others all engines are available at launch directly (??)
« Last Edit: February 12, 2014, 12:33:54 PM by sami »

Offline meiru

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Re: MD-88 range
« Reply #9 on: February 12, 2014, 01:30:33 PM »
I know that all engines existed after November 1983, but the MD-82 was in service in august 1981, so that means, that at least the 217 version was available then... if the 219 also or only 2 years later, that's unknown to me... I could try to find out

that's for the engines

and the 88 had a larger range than the 83, when equiped with the same fuel system the 83 had... this didn't result in a higher MTOW, but in about 600 gal more fuel ... I don't know if you want to implement this as 2 weight variants

... there are more options to think about, but it's not needed to implement everything (like the even larger tank system).

Offline meiru

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Re: MD-88 range
« Reply #10 on: February 12, 2014, 01:54:39 PM »
Document from McDonnell Douglas, February 1988

MD-83 -> range 2549nm
MD-88 -> range 2554nm (with additional fuel tank)

and there's also an 87 with 219 and additional fuel tank for 2784nm

but at least the 88 is interesting (the versions have different MTOW in this document by the way -> 149.5k lbs and 160k lbs)

it was available also in other combinations, but we don't need that... two weight variants would be fine for the moment (the smaller is listed with the 217C in this document -> resulting in a lower fuel burn in real life)

Offline schro

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Re: MD-88 range
« Reply #11 on: February 12, 2014, 03:56:01 PM »
Quite frankly, the MD88 range in game now is far and above what they're operationally able to be used for in real life. I.e. a standard MD88 can't do ATL-LAX without a fuel stop on a reliable basis, PHX is a stretch. Why would the range need to get buffed more?

Offline meiru

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Re: MD-88 range
« Reply #12 on: February 12, 2014, 04:54:41 PM »
The 88 had the same fuel system the 83 has. So it is possible to fly them > 2500 nm ... and there was an option for an even larger fuel tank that allowed it to fly > 3100 nm... the 88s currently in use are mostly not equiped with this tank, giving a range of about 2100 nm. Thats a fact! That's why it should be in the game. It's not the question if you would like to fly in a MD-80 on a 2500 nm trip...

Curse

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Re: MD-88 range
« Reply #13 on: February 12, 2014, 04:55:55 PM »
It could be implemented as a prototype aircraft then?

ucfknightryan

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Re: MD-88 range
« Reply #14 on: February 12, 2014, 05:04:36 PM »
The 88 had the same fuel system the 83 has. So it is possible to fly them > 2500 nm ... and there was an option for an even larger fuel tank that allowed it to fly > 3100 nm... the 88s currently in use are mostly not equiped with this tank, giving a range of about 2100 nm. Thats a fact! That's why it should be in the game. It's not the question if you would like to fly in a MD-80 on a 2500 nm trip...

I think you mean the MD-82?  Everything I have ever seen suggests that the basic MD-88 is an upgraded MD-82.  Not saying it wasn't available with the bigger fuel tank of the MD-83 as I don't know one way or another on that.

Offline meiru

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Re: MD-88 range
« Reply #15 on: February 12, 2014, 05:06:15 PM »
It was not only a prototype... 88s with this tank system exist. I once even found one for sale  :)

And the 83 of TWA were 88s... maybe I should explain this a little further. The 81, 82, 83 and 88 were almost the same aircrafts with different options. The number increased over time, but in the end of the production there were not many differences between 82/83/88s ... the airline more or less did select the number they wanted. The 88 for example was the idea of Delta... they thought, that their "package" was worth to get the number 88 ... and McDonnell Douglas named it 88... that's all. That's also why it's so difficult to say what types we should add to the game. I counted more than 14 versions!

I know, that there's for example an MD-82 and an MD-83 with a MTOW of 149500 lbs and JT8D-217C engines and the exact same fuel system... so, why is one an 82 and the other one an 83? ... I don't really know that... I didn't find anything that could explain it.
« Last Edit: February 12, 2014, 05:09:54 PM by meiru »

 

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