I am looking the possibility of staying with full winglet and
 small mid
 fuselage fin , to increase the yaw control i will built each side
 of the
 nose some flaps who will be interconnected between each winglet
rudder  you see what i means similar to the gas door on car but much
 bigger by
 cutting part of the nose each side and lay inner skin and separated
 with tape to prevent stikking together.


 Jean Prudhomme


 Jean, if I'm reading this correctly, your putting "airbrake"
type flaps on the sides of the fuse
 for yaw control? I think this would be a big negative for
several reasons.

 1- disrupted flow over the wing, and now the prop.
 2-Having the 'flap' infront of the CG could have an un-stabling
effect.  3- Drag for yaw control to counter single engine
operations is just .. not
 good [you can NEVER have too much thrust during single engine
operations] IMO.

 Had to put doing the FEA off over the weekend.. but I'm back on
it here today.. :)

 J. Johnson


Thank,s for your comments on this subject but i do have some
alternative by
the central fin rudder.

If i loose one engine the opposite flap can be operated with a linear
actuator without been in relation with rudder operation.

I really dont know how much it can affect the wing airflow because
it will be located below the wing airfoil cord and strake cord
 also below the canard


Jean Prudhomme

The central fin is going to help, but only to a limited capacity if the lever arm
isn't increased. Come to think of it, an increase in tail length is probably a good thing
due to the higher drag region there at the rear of the airframe due to
it abrupt ending and no prop to pull the flow in. The negative here is
the extra surface area but I think it's a small price to pay for overall
improved flow in that area.

If you lose an engine, you'll be pulling the 'flap' that is on the good
engine side, not the opposite side. This will still effect the prop
as no matter where it's located it's going to shed alot of turb.

Also, if it's below the canard [not on the horizontal waterline]
it's going to add a pitch change in there, another thing which is not
terribly exciting when flying single engine [ok.. it'd be exciting but
not in a good way]..

Lastly I don't know how much single engine time you've flown in
a twin but you can trust me when I say there is never enough thrust
during single engine opperations, using a drag application to maintain
directional control during single engine operations is just asking for
an accident. I can't stress enough the fact that the airframe should be
directionally stable using conventional control surfaces down to at least
85% of Vso. It wasn't until light twin companies started to get aggresive
w/ lower Vmc numbers that they started to see an improvement in there
stats. If you have to stall before you get to Vmc your very likely never going to
have a problem, this is my opinion, but it's a safe one :)

Best

Jarrett