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equations of motion for flying wing

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Old   July 2, 2014, 07:30
Default equations of motion for flying wing
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Hai all,
I've recently read about equations of motion(6 degree of freedom) for conventional aircraft and he gave 6 equations(3 for linear motion and 3 for angular motion). He considered "downwash effect" in deriving the equations. But I think for a flying wing, downwash effect should be neglected.
So can any one of you please tell me whether I can neglect the term regarding downwash effect completely or I need to consider any term replacing that
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Old   July 2, 2014, 10:55
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What do you exactly mean?

Downwash effect on tail or downwash effect on main wing?
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Old   July 2, 2014, 12:11
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downwash effect on tail. For a flying wing there'll be no tail. So, in the equations of motion which are derived for a conventional aircraft, the term representing downwash effect on tail should be neglected but my doubt is, whether we should consider any other term replacing that or can we simply neglect
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Old   July 3, 2014, 08:30
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Sure, no tail - no tail downwash.

I assume that you know that cg of flying wing is in the front of aerodynamic center and pithc stability is achieved due to sweep and twist or/and special reflexed airfoils. You just need to know total wing lift slope d Cl/d alpha and distance between the aerodynamic center and cg. How to compute these two parameters is another question.
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Old   July 10, 2014, 03:16
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Thank you. Is there any material/text book which can guide me in calculating stability derivatives and simulating "autopilot for flying wing UAV". That is a part of my academics and I thinking of simulating autopilot using MATLAB
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Old   July 10, 2014, 22:17
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These texbooks are similar: you can take, for instance, this one

https://courses.cit.cornell.edu/mae5...ey_2011_04.pdf

There are several free software on the internet which compute stability derivatives: one of them Mark Drela's AVL

http://web.mit.edu/drela/Public/web/avl/

You can also try user-friendly XFLR5

http://www.xflr5.com/xflr5.htm
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