REFLECTOR:RE: Fences
Chris Martin
reflector@tvbf.org
Sun, 18 Jan 2004 12:16:25 -0800
John,
The design of these fences is the brain child of Klaus Savier. A brilliant
guy who holds all of the speed records in his Long EZe.. He also makes the
Light Speed Ignition system which I am using two of in my plane. I'm flying
an XL RG with a Lyc. IO540 and a MT prop. The addition of the fences, 2
each wing, have made the plane much easier to control in landing's and
takeoff's. The plane just flys straighter when the gear is down. Many
people have a problem of the gear doors acting like rudders and pulling the
plane around. The fences make it fly like it's on rails. I have noticed
that starting a turn now definitely needs to be lead with rudder especially
below 120 kts. So, just in handling alone it was worth it. Take offs and
landings are also improved by a reduction of 200 to 300 feet. The final
blessing was an increased top speed. I worked with Klaus Savier in the
design of these and Klaus said that the improved wing efficiency at high
speed causes the angle of attack to be reduced by about 1 to 1.5 degrees.
This gives you a lower profile and subsequent reduced drag. Thus a speed
improvement of 3 to 4 knts. At present I have two fences per wing and am
considering 1 more at Klaus's suggestion. My fences are on each side of the
aileron. When I add the third it will be 2/3 of the distance from the end
of the aileron to the winglet.
I attached some of the other builders comments from the archives and will
try to get you some pictures .
Chris Martin
> > 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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> >
> > ------------------------------------------------------------------------
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> >
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>
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Christopher Martin
christophercmartin@earthlink.net
Why Wait? Move to EarthLink.
> [Original Message]
> From: johnward <johnward@gulftel.com>
> To: <christophercmartin@earthlink.com>
> Date: 1/18/2004 8:33:42 AM
> Subject: Fences
>
> Chris,
> I believe Scott Baker said he talked with you about the trailing edge
> fences like the ones on E-Racer in the 2003 November issue of Sport
> Aviation. If possible could you give me any details regarding size and
> placement. I have a Standard Elite (RG). Wish it was an XL with a
> supercharger.
>
> Thanks,
> John Ward
>