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convexengineering / SPaircraft

Models for commercial aircraft design
http://spaircraft.readthedocs.org
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Weight increase from M07_737 to D8_eng_wing +heavy VTs (>200% off) in optimal_D8 #86

Closed 1ozturkbe closed 7 years ago

1ozturkbe commented 7 years ago

Investigating...

mayork commented 7 years ago

I think this coile be related to the other issue about June 13...check the commits right before 13 June

1ozturkbe commented 7 years ago

Nothing seems out of the ordinary about those commits. All I did about the VT was to rename TASOPT_VT to be D8_VT, and removed the old D8_VT. Will need to dig still.

mayork commented 7 years ago

Did i screw up the merge? It wouldn't be the first time...😬

On Jun 23, 2017, at 11:22, Berk Ozturk notifications@github.com wrote:

Nothing seems out of the ordinary about those commits. All I did about the VT was to rename TASOPT_VT to be D8_VT, and removed the old D8_VT. Will need to dig still.

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1ozturkbe commented 7 years ago

Seems like this is (at least) part of the issue. Found some rogue subs in optimal_D8. Will fix.

1ozturkbe commented 7 years ago

Even after fixing some rogue subs, we are still around 200% off on VT weight. Will be posting updates here on debugging this.

1ozturkbe commented 7 years ago
vspcompare

Adding VSP comparison of standard killer plots, steps 2 and 1.

1ozturkbe commented 7 years ago

Part of this also has to do with issue #88. Again, work in progress...

1ozturkbe commented 7 years ago

God... one of the reasons we had an issue is because of a bug we had while reordering constraints, and messed up the tail impact loads... Good thing I'm doing #89 .

1ozturkbe commented 7 years ago

With the fixes I have made, we are still quite heavy (~100%). I am going to investigate this along with the HT lightness issues in #88.

1ozturkbe commented 7 years ago

Woooow, I think I know... it is because there is no load factor for the tails; they are just designed for max loads at Vne, duuuuh. So Nlift = 1. Let me see what this does.

mayork commented 7 years ago

I don't think VT AR is a mistake. Our low fidelity aero model coupled with our structural model pushes the AR unrealistically low so I've had all the files set up to solve with a min VT AR

1ozturkbe commented 7 years ago

The VT is fine now, it's the HT that is not. Will wrap all of this up shortly.

1ozturkbe commented 7 years ago

Alright, the HT's are coming out low in weight because they have tiny aspect ratios. Big root chords are allowing the HT's to be really lightweight. Otherwise the structural models are sound, and the VTs are all on point.

mayork commented 7 years ago

HT used to work fine with a free AR. Could it be from the new structural model?

1ozturkbe commented 7 years ago

I'm closing this, because I think we understand and accept that the both tail surfaces are going to be light.