equations of motion for flying wing

raj777 · July 2, 2014, 08:30

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

truffaldino · July 2, 2014, 11:55

What do you exactly mean?

Downwash effect on tail or downwash effect on main wing?

raj777 · July 2, 2014, 13:11

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

truffaldino · July 3, 2014, 09:30

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.

raj777 · July 10, 2014, 04:16

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

truffaldino · July 10, 2014, 23:17

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

July 2, 2014, 08:30	equations of motion for flying wing	#1
raj777 New Member Rajkumar Join Date: Jul 2014 Posts: 5 Rep Power: 12	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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July 2, 2014, 11:55		#2
truffaldino Senior Member Join Date: Jan 2011 Posts: 249 Blog Entries: 5 Rep Power: 17	What do you exactly mean? Downwash effect on tail or downwash effect on main wing?

July 2, 2014, 13:11		#3
raj777 New Member Rajkumar Join Date: Jul 2014 Posts: 5 Rep Power: 12	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

July 3, 2014, 09:30		#4
truffaldino Senior Member Join Date: Jan 2011 Posts: 249 Blog Entries: 5 Rep Power: 17	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.

July 10, 2014, 04:16		#5
raj777 New Member Rajkumar Join Date: Jul 2014 Posts: 5 Rep Power: 12	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

July 10, 2014, 23:17		#6
truffaldino Senior Member Join Date: Jan 2011 Posts: 249 Blog Entries: 5 Rep Power: 17	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