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


HI jarret
i Use to own a cessna 310 which i rebuilt after wing colapse on
tip tank and explode ,i have over  1000 hrs on twin and i lost
one engine on take off i know what it feel also one time one
main gear major door open just after take off it feel like eavy
crosswind and it was during the first flytest after i replace
the other wing who was burned.

With le lost of an engine it yaw at the side of lost engine but
the front flat have to counter this reaction to bring the nose
on the good  engine side so this is the lost engine flap will be
in operation.

As per my experience building composite airplanes it,s not a big
deal building those flaps and try it, testing give you more
accurate answer,i built 7 Velocity and flytest several others.

iI listen all comments on those topics and i am keeping learning
and it will help me more on my project construction


Thank,s for your assistance



Jean Prudhomme

Jean, it would appear that you've the experiance  to understand
single engine operations [maybe an understatement :)]. Just be safe
and if you do use these flaps, lots of testing before you count on them
for the real deal :)

I still don't follow the reasoning behind using the flap on the same
side as the dead engine but I must be missing something.

Best regards,

Jarrett