Flaps, Gaps and Brackets (was gobbledegook)
Posted: Fri Feb 17, 2012 5:46 pm
1. Reflex Position - Are you sure about the loss of negative flaperons, aka
reflex position, with split flaps? I was told by the factory that one of
the improvements to the fuselage design when the Elite was designed was to
change the fuselage contour so that it would be aligned with the flaps (or
flaperons) when they were in the reflex position. I believe that is 5
degrees up. If you are used to seeing the Rebel flaperons higher than the
fuselage when in the highest, reflex position and then see the Elite even
with the fuselage in the highest position, it doesn't necessarily mean the
control surfaces are not in the reflex position. Need to check with the
contour of the wing to tell (or ask Murphy). Since both the split controls
and the flaperons still use the same mixer arrangement to control the
flaps/flaperons/ailerons and the up position can be rigged anywhere, I don't
see there is any reason the reflex position wouldn't exist for both the
split flap/ailerons or the flaperons. I believe the uppermost flap position
on the Elite is 5 degrees reflex. Also, when I operated the controls of the
factory taildragger Elite, both the flaps and the ailerons changed position
when the flaps were operated. I can't recall if the ailerons moved down as
far as the flaps in all positions, but they did assume a different, more
downward, or upward, position in unison with the flaps as the flap handle
was moved through its positions. It seems at some point they must diverge
because I believe you can have more flap extension with the metal, 3 support
flaps, but you probably wouldn't want the ailerons to go down that far.
Guess I could check my manual, but then I would miss the opportunity to look
stupid in public.
2. Flaperon Brackets - Should the lack of redundant support for the control
surfaces be a concern? The Rebel shares the center hanger bracket with both
the flap and the aileron. If that bracket failed, even on a flaperon
airplane, what is to prevent a simultaneous loss of support of the flap and
aileron at one end? Unfortunately, it is not a simple matter of adding a
mid span support to the flap and aileron, as the Elite does, since this will
be structurally sound only for the metal covered control surfaces, according
to Darrel Murphy.
3. Gap Problem - I think the early Elite "problem" was due to a combination
of air flow things including a redesigned empennage, fuselage and the fact
that the metal flaps could be extended further which may have caused some
new and wondrous airflow across the tail. I believe that situation,
experienced only during prototype testing in the first few flights of the
first Elite, was solved by a design tweaking of the horizontal stabilizer.
I remember visiting the factory several years earlier when they first rigged
a Rebel with split flap and aileron as a precursor to the current design.
To my knowledge, they did not experience any problems associated with a gap
and still had a reflex position available.
4. Cessna??? - I think if the "Beaver did it, it must be good!" Does the
Beaver, the premier bush plane and floatplane, granddaddy of the Rebel, use
split flaps and ailerons or flaperons? Guess I'll have to mosey down to
Kenmore Air and find out unless someone here can enlighten me.
5. Mixed Metal/Fabric Control Surfaces - Help!! - Right now I am in a
quandary. I prefer the fabric control surfaces in the flaperon
configuration, but I confess that I worry about that common aileron/flap
center bracket design. I can build it either way since I am building an
Elite, but upgraded from a Rebel. Prior to getting the higher strength
Elite wings, I had already completed the fabric ailerons and flaps. So I
have both the metal and the fabric control surfaces and all the parts. My
current thought is a compromise where I will go with a metal flap having 3
supports and a fabric aileron having 2 supports. I would like to couple
them together as flaperons, but I am uncertain of any flutter consequences.
If I split the metal flaps and fabric ailerons, I can use a greater flap
extension position because of the stronger flaps and supports, but I miss
out on the benefits of flaperons for low speed control. Floats are in the
future, but I can change then if necessary. Any wisdom out there to help me
past this decision?
Sorry for the long post. Probably should have broken it into several
emails. I went back and added numbers and titles so anyone could
selectively respond if they desired and future readers could find the
subject in the archive files. This subject is of particular concern to me
and I greatly appreciate the thoughts and experience that this forum
contains.
Thanks,
Chuck Skorupa
Elite S/N 500 (taildragger config)
----- Original Message -----
From: "Bob Patterson" <bob.patterson@canrem.com>
To: "Murphy Rebel Builders List" <murphy-rebel@dcsol.com>
Sent: Monday, May 08, 2000 8:35 PM
Subject: RE: gobbledegook
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reflex position, with split flaps? I was told by the factory that one of
the improvements to the fuselage design when the Elite was designed was to
change the fuselage contour so that it would be aligned with the flaps (or
flaperons) when they were in the reflex position. I believe that is 5
degrees up. If you are used to seeing the Rebel flaperons higher than the
fuselage when in the highest, reflex position and then see the Elite even
with the fuselage in the highest position, it doesn't necessarily mean the
control surfaces are not in the reflex position. Need to check with the
contour of the wing to tell (or ask Murphy). Since both the split controls
and the flaperons still use the same mixer arrangement to control the
flaps/flaperons/ailerons and the up position can be rigged anywhere, I don't
see there is any reason the reflex position wouldn't exist for both the
split flap/ailerons or the flaperons. I believe the uppermost flap position
on the Elite is 5 degrees reflex. Also, when I operated the controls of the
factory taildragger Elite, both the flaps and the ailerons changed position
when the flaps were operated. I can't recall if the ailerons moved down as
far as the flaps in all positions, but they did assume a different, more
downward, or upward, position in unison with the flaps as the flap handle
was moved through its positions. It seems at some point they must diverge
because I believe you can have more flap extension with the metal, 3 support
flaps, but you probably wouldn't want the ailerons to go down that far.
Guess I could check my manual, but then I would miss the opportunity to look
stupid in public.
2. Flaperon Brackets - Should the lack of redundant support for the control
surfaces be a concern? The Rebel shares the center hanger bracket with both
the flap and the aileron. If that bracket failed, even on a flaperon
airplane, what is to prevent a simultaneous loss of support of the flap and
aileron at one end? Unfortunately, it is not a simple matter of adding a
mid span support to the flap and aileron, as the Elite does, since this will
be structurally sound only for the metal covered control surfaces, according
to Darrel Murphy.
3. Gap Problem - I think the early Elite "problem" was due to a combination
of air flow things including a redesigned empennage, fuselage and the fact
that the metal flaps could be extended further which may have caused some
new and wondrous airflow across the tail. I believe that situation,
experienced only during prototype testing in the first few flights of the
first Elite, was solved by a design tweaking of the horizontal stabilizer.
I remember visiting the factory several years earlier when they first rigged
a Rebel with split flap and aileron as a precursor to the current design.
To my knowledge, they did not experience any problems associated with a gap
and still had a reflex position available.
4. Cessna??? - I think if the "Beaver did it, it must be good!" Does the
Beaver, the premier bush plane and floatplane, granddaddy of the Rebel, use
split flaps and ailerons or flaperons? Guess I'll have to mosey down to
Kenmore Air and find out unless someone here can enlighten me.
5. Mixed Metal/Fabric Control Surfaces - Help!! - Right now I am in a
quandary. I prefer the fabric control surfaces in the flaperon
configuration, but I confess that I worry about that common aileron/flap
center bracket design. I can build it either way since I am building an
Elite, but upgraded from a Rebel. Prior to getting the higher strength
Elite wings, I had already completed the fabric ailerons and flaps. So I
have both the metal and the fabric control surfaces and all the parts. My
current thought is a compromise where I will go with a metal flap having 3
supports and a fabric aileron having 2 supports. I would like to couple
them together as flaperons, but I am uncertain of any flutter consequences.
If I split the metal flaps and fabric ailerons, I can use a greater flap
extension position because of the stronger flaps and supports, but I miss
out on the benefits of flaperons for low speed control. Floats are in the
future, but I can change then if necessary. Any wisdom out there to help me
past this decision?
Sorry for the long post. Probably should have broken it into several
emails. I went back and added numbers and titles so anyone could
selectively respond if they desired and future readers could find the
subject in the archive files. This subject is of particular concern to me
and I greatly appreciate the thoughts and experience that this forum
contains.
Thanks,
Chuck Skorupa
Elite S/N 500 (taildragger config)
----- Original Message -----
From: "Bob Patterson" <bob.patterson@canrem.com>
To: "Murphy Rebel Builders List" <murphy-rebel@dcsol.com>
Sent: Monday, May 08, 2000 8:35 PM
Subject: RE: gobbledegook
GeertHi Brian !
I doubt you'll hear ANY good stories about split flaps & ailerons
- the factory still only allows 6, 12, and 18 degrees of flap, even if
they are separate, because there are only 2 flap hanger brackets.
This means that you get half the flap, and half the aileron you
would normally get as flapperons, plus - you lose the advantage of
negative flapperon to increase cruise and stability ! Not a desirable
situation !!! Several float pilots have commented that the flapperon
really improves takeoff & landing performance on the water, as you
are changing the whole airfoil, instead of having a gap which generates
considerable turbulence... (remember the early Elite problem !)
But, some folks think that "Cessna did it, so it must be good" !! ;-)
.....bobp
----------------------------------orig.---------------------------------
At 12:26 AM 5/4/00 -0400, you wrote:Hi There
I am not convinced at all that splitting the flaps is a good idea. As
inputmentions, you will defintely lose aileron effectiveness. On strong
crosswind landings, I find that you want all of the available aileron
youto keep it tracking down the centre & there are still times that I don't
have enough. I know that I am FAR from a great pilot, but my
feeling/opinion is that you want all the aileron input which the 12'
aileron/flapperon can give you.
Also, I can't really imagine what great benefit the split flap can give
full.as the stall is low, and I find that I prefer half flap on landing vs.
splitMaybe someone can comment & tell us of their positive experiences with
cameflaps.
Brian #328R
-----Original Message-----
From: Geert Frank [mailto:storchpilot@mediaone.net]
Sent: Tuesday, May 02, 2000 10:11 AM
To: murphy archives
Cc: Jan Eggenfellner
Subject: gobbledegook
Hi everybody. I must have the same machine as bobp, the May 1 summation
getthrough almost all HTML i.e. not plain text. Ian, sorry I too wanted to
todown to 8 instead of 12 bungee rings...(the 400 lbs rings), primarily to
soften up those landings a little. It does not work, the gear is now much
too "soft". Dave B. who had two landing gear failures also strongly
recommended to use all 12 loops. Next, for the person that is trying
heavylift an UTVA tail (?, Wayne hisself?) the Rebel I don't think is that
Iback there, but I made up a simple sling using a horse saddle belly
strap(cinge) which is fleece covered and has two very sturdy rings, $ 20.
dutyused a 24" piece of pipe, drilled three holes into same (use drill press
only, handheld drill will put you in mental home!) and stuck one 3/16
eyebolt upwards in the center and two downward at the ends.
Two pieces of 3/16" cable, one piece for each side (24" for the Rebel,
including loops). Attach three of the cable ends directly to the down
eyebolts and rings in cinge, using a shackle and two cable clamps at each
point, one end attach it to one of those quick disconnect snaps( heavy
aplease) and you can lift the tail by your own self. I use one of those
engine mini cranes, hook of course through the top eye. Or you could use
enoughsimple come-along attached to the rafters providing they are strong
kitsof course. I place my lift strap just forward of the lift handles I have
installed. Over the rivetline of course. Ok? Next a few questions: is
there a list somewhere of what actually happened to the over 600 Rebel
completedsold? How many projects were abandoned? How many flying? How many
onlybut not flying? Why only 132 (correct?) people active on this site? I
forsee about six to eight names appear myself, but I'll take someone's word
2.5that 132 figure. To use the cliche: Where IS everybody??? I have
temporarily abandoned the upgrade from my 2.2 liter Subaru Legacy to the
alsoliter Eggenfellner one. It almost makes use of an electric c.s. prop
mandatory and there goes another $ 4000. My D I Y junkyard 2.2 liter is
Irunning fine with it's 3-bladed Warpdrive. I found the summation of the
Subaru conversions by Ken K. quite interesting and actually pretty fair.
Rebeldo agree on the resale value, but I also heard of some guys buying a
beprecisely because it had a Subaru engine. Go figure! One thing seems to
older?never mentioned: you buy a used many times overhauled Lycoming, you are
sitting behind some old stuff, going back to what year? 1968, 1972,
almostMy engine was not "born" until 1990. Eggenfellner seems to be using
ofall1999 or 2000 engines. That gives me a lot more confidence.
Finally I still have the seperate flaps on my Rebel. Can I hear from some
allthe experienced guys, to yes or no convert back to flaperons? I am not
thanks,that happy with the aileron effectiveness, so I am considering. Many
-*--------------------------------------------------------------------------Geert
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The Murphy Rebel Builders List is for the discussion
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Archives located at:
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*---------------------------------------------------------------------------*----------------------------------------------------------------------------------*
---------**--------------------------------------------------------------------------The Murphy Rebel Builders List is for the discussion
between builders and owners of Murphy Rebel aircraft.
Archives located at:
http://www.dcsol.com/murphy-rebel/lists/default.htm
---------*
--------*
*---------------------------------------------------------------------------The Murphy Rebel Builders List is for the discussion
between builders and owners of Murphy Rebel aircraft.
Archives located at:
http://www.dcsol.com/murphy-rebel/lists/default.htm
--------*
*-----------------------------------------------------------------------------------*
The Murphy Rebel Builders List is for the discussion
between builders and owners of Murphy Rebel aircraft.
Archives located at:
http://www.dcsol.com/murphy-rebel/lists/default.htm
*-----------------------------------------------------------------------------------*
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