Toronto Electric Model Aviation Club Forum

Toronto Electric Model Aviation Club (TEMAC) => General Discussion => Topic started by: Frank v B on November 15, 2014, 08:43:12 PM

Title: E-rodynamic question
Post by: Frank v B on November 15, 2014, 08:43:12 PM
A thought just crossed my mind while building the Skywriter biplane wings.  I have chosen to install 4 HS55 servos in the wings.


Can I make the top wing respond to flapperon (or flap) setting while the lower wing continues to respond as an aileron for landing?  Don't worry about the "how?" to do it.  Especially don't worry about the "why?".   This is just a theoretical aerodynamic question.
I know flapperon is dangerous on a monoplane with full span ailerons because it has the effect of adding "wash-in" into the wing.
This seems to have the best of both worlds.



Yes Andy, I will now return to my workshop and shut up.


Frank


If Simon H. reads one more article on aerodynamics he will become our resident expert. :D
Title: Re: E-rodynamic question
Post by: Papa on November 15, 2014, 09:43:19 PM
I imagine that Right Up Aileron and Right Down Flap would negate each other and also slow the wing down a huge amount while the opposite wing would have both down which would exert tremendous force. I think you would have a massive yaw on one wing while the other was trying to roll at a rapid rate.


It makes no sense which is probably why it's never been used before. I know that's a "why" but I don't care.


Jack.
Title: Re: E-rodynamic question
Post by: Frank v B on November 15, 2014, 10:45:19 PM
Who let Jack loose from quarantine north-east of the city? ;D


Frank
Title: Re: E-rodynamic question
Post by: sihinch on November 15, 2014, 10:50:28 PM
I think in theory that yes, it would work.

Use bottom wing for flaps and top for ailerons.

just bassed on intuition!
Title: Re: E-rodynamic question
Post by: Frank v B on November 16, 2014, 11:13:55 AM
I can see Jack's point about cancellation but I am leaning towards Simon's view. 


If one wing acts as a flap with both ailerons down then the plane is in a new stable flight condition.  When the second wing is deflected and acting as an aileron it will handle the roll axis but on a low rate setting since only half the aileron area is being deflected.


I would love to try it but why invent a new way of crashing.


Frank
Title: Re: E-rodynamic question
Post by: Ededge2002 on November 16, 2014, 11:48:37 AM
Another thing to consider is the drag.  Biplanes with all there struts and rigging have much more drag than a monoplane of the same area.  The use of flaps on a lightly built biplane might make it slow too much requiring it to be powered right to the ground(something you should be an expert at Frank!) 

Instead of flaps I would consider adding a little spoiler to all surfaces to lessen the stall.  Again as above just a thought
Title: Re: E-rodynamic question
Post by: pmackenzie on November 17, 2014, 06:35:42 PM
With normal stagger (top wing ahead) then it might be safer topuse the top wing as the flapped one.
The flapped wing will stall first dues to the higher AOA, so the nose will drop.
The other way around could result in the tail dropping in a stall, which would not end well. :o

Pat MacKenzie
Title: Re: E-rodynamic question
Post by: Skyking on November 18, 2014, 01:21:40 PM
It's so easy!
Just remember that the bottom is twice as less.
Sheesh.
How about some hard questions?


Ken