REFLECTOR: Trailing Edge Aileron Fence and door open emergency procedures

Scott Derrick reflector@tvbf.org
Thu, 31 Jul 2003 20:07:04 -0600


Rodney,

Thanks a bunch for the info and pics!

Scott

Rodney Brim wrote:
> Hi,
> Sorry I'm a month late in responding.  Am fighting cancer and low energy and
> don't get to the plane much to measure or take pictures.  But I recently did
> and here they are.  I also looked up my original research.  The take-off
> roll was reduced by over 20% not 15%.  Actually at the time I measured it,
> it was roughly 22%.
> 
> Before I do the numbers and picture story I want to suggest you all add a
> comment to your emergency procedures.
> 
> 1. If the door pops open fully, DO NOT TURN AWAY FROM THE OPEN DOOR.
> 
> If you, like I, ever have that experience.  You will start a rapid roll away
> from the door to an inverted position.  For me the door opened slightly as I
> departed... with the gear coming up it pressurized the cabin and pops the
> door wide open, and then if you turn away from the door (to head back to the
> airport) it wants to roll and spin into the ground, in my case at about 200
> feet.  Opposite rudder and aileron will hold you at a 60 degree bank angle,
> but won't get you out of the fix as you're going to stall in that
> configuration.  There is a way out, but that's another conversation.  OK
> back to trailing edge fence.
> 
> I've attached a couple of pictures.  They are located on the inboard side of
> the ailerons.  They point directly into the wind.  If you are testing, you
> can cut them out of plexiglass clipboards and hot glue them in place.  I did
> for all of my testing.  I also wrote this up in an article in Velocity Views
> a couple of years ago.
> 
> Specs:
> 1. Position.  They are located on the inside of the aileron, but face
> directly into the wind, not the angle of the aileron.
> 2. They extend back from the trailing edge 1.5 inches, and 5 inches above
> the trailing edge and 2.5 inches below.
> 3. From that position the top and bottom dive into the wing.  The length of
> the top (from wing to end of trailing edge) is 12 inches.  The bottom is 9
> inches, but note that's because the trailing edge of the stall fence is not
> perpendicular to the ground.  Instead of dropping at a 90 degree angle at
> the top (which may be a preferable design), I slopped mine forward at a 70
> degree angle.
> 
> |---- 12 "------------------  70
>                           -
>                          -
>                         -
>       |--- 9" ----------|
> 
> 
> That's roughly the shape in a text format, except the bottom slopes up to
> meet the underside of the wing and the top slopes down to meet the top.  But
> both of those may be better served by having a longer run into the wing.
> Klaus was the one who helped me with this and it wasn't a value at the time.
> 
> Hope that helps.  Fly safe.
> 
> 
> 
> Rodney Brim,
> 
> 
> -----Original Message-----
> From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
> Behalf Of Rene Dugas
> Sent: Thursday, May 29, 2003 3:24 PM
> To: reflector@tvbf.org
> Subject: RE: REFLECTOR:Aileron Fence
> 
> 
> I would be interested in dimensions and locations  of fences.
> Thanks,
> Rene'
> XL RG
> rdugas@bayou.com
> 
> -----Original Message-----
> From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org] On
> Behalf Of Rodney Brim
> Sent: Thursday, May 22, 2003 9:12 PM
> To: reflector@tvbf.org
> Subject: RE: REFLECTOR:Aileron Fence
> 
> Hi Chuck,
> 
> 1. I got a >15% reduction in take-off roll on my final version of the
> fences.  Looks like that is attributable to driving the air more
> directly
> over the wing at slower speeds and not having it slide down the wing,
> which
> if you do some dirty oil tests you will see that it is doing.
> 2. It doesn't effect your stall, that's all governed by the canard.
> 3. It feels like it reduces roll rate slightly.  I didn't measure it,
> but
> you can tell the plane has more tail feathers, especially as you move
> the
> fences out along the wing, which I would not suggest.  To me it makes
> the
> plane feel more stable.
> 4. Reduction in cruise speed is dependent upon height of the fences and
> location.  At the location and height I have them, I have no reduction
> in
> cruise speed.
> 
> 5. I think they should be standard on the kit... but then what do I
> know.  I
> think everyone should move to forward hinging doors;)
> 
> Rodney Brim,
> PS I have a picture and dimensions if you want them.  They probably
> helped
> save my neck as I had an ugly door pop, going inverted stall at 200 feet
> coming off a runway a couple of years ago... sometimes you can use all
> the
> stability and directional control you can get your hands on.
> 
> 
> -----Original Message-----
> From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
> Behalf Of Chuck Jensen
> Sent: Thursday, May 22, 2003 7:30 AM
> To: 'reflector@tvbf.org'
> Subject: REFLECTOR:Aileron Fence
> 
> 
>>From the Newsletter, some preliminary flight testing seemed to show
> than an
> inboard aileron fence had merit for reducing takeoff distance,
> increasing
> climb rate and perhaps reducing stall speed while not affecting cruise
> performance and turning characteristics.  Has this become a concensus or
> is
> the jury still out?  And, is there a standard template for such a fence?
> 
> Chuck Jensen
> XL RG
> 
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