Since you don't need to re-trim between cruise and landing configurations
does indicate your aircraft is near zero w/r/t pitch stability ... goes
where you put it ... regardless of airspeed.
Big goose egg this week on the project ... we're in Libby visiting the home
front. But when I do get to flying it, like you, I'll be sharing initial
flight reports.
Bob 612e
-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com]On Behalf Of
michael betti
Sent: Monday, April 02, 2007 9:54 AM
To: rebel-builders@dcsol.com
Subject: RE: [rebel-builders] Elite flying....Al H.
There isn't really much for feed back from the stick. and really have
no need for trim. I don't use the trim at all. It flys at cruise hands
off, and during landing the change isn't that I need to retrim.
Looking forward to hear about your test flights.
Mike
----Original Message----
From: robert@montanasky.us
Date: 04/02/2007 7:14
To: <rebel-builders@dcsol.com>
Subj: RE: [rebel-builders] Elite flying....Al H.
Mike,
Flew an RV4 two weekends ago. It recovers nicely from pitch-down
nudges at
varying speeds. Also, an increase in airspeed, for a given pitch trim
setting, does require resetting pitch trim to remove the new pitch up
tendency. So I would say this RV4 anyway does not display similar
Elite
pitch behavior.
Having made the elevator tip mods as you and others have, I'm now
thinking
(in hind sight) I should have done it like you recently mentioned -
cut
down the elevator spades on the inside, followed by stab build up to
fill
the gap. This would have increased the stab area (retaining the
originally
designed tail area), while also decreasing the elevator's "power
steering".
Doing the mod the way I (and others) seems to remove the elevator's
return-to-neutral condition, but at the same time reduces the overall
tail
area (stab and elevator combination); which doesn't help the pitch
stability issue. With the Elite, I think the stab area plays as big
role
as the elevator tips do ... perhaps even more ... my two cents ...
never
actually flown one ... so my words here are speculative at best.
My modified elevator tips measure 3-1/4" wide. This is a 3/4" more
cut per
tip then Al's or Mike's 4" wide tips. In doing so, I also have
reduced the
over-all width of the tail feathers by 1-1/2" more then Al's or
Mike's. If
612e is pitch divergent, then I'd have to say the "main" problem is
not the
elevator tips, but a marginal stab area. Not too much longer and I'll
have
the answer to this one.
From what I've read, I'm thinking the Elite's pitch stability must be
pretty close to zero across most of its CG range. Where a slightly
positive value indicates a return to original condition after a nudge,
a
slightly negative value indicates divergence - continued pitch
acceleration
in the same direction as the nudge, and a zero value indicates the
aircraft
stays were you put it - with no tendency to change on its own. There
is an
aft C.G. value that will create a zero pitch stability condition, and
this
should be at the aft C.G. of the working flight envelope ... or just
fwd of
that value. Question is, for the Elite, how do we get that neutral
point
C.G. aft of the working flight envelope.
At a given airspeed trimmed for pitch hands off condition, if an
increase
in airspeed creates a requirement to add nose down pitch, the aircraft
must
be on the positive side of the neutral (or zero) pitch stability
value,
which means it will eventually return to the original flight condition
-
even if you may not live long enough to see it happen. I would think
this
would be after the new airspeed stabilizes ... not during the
acceleration
phase of getting to that new airspeed.
I might have missed it in this thread, but Mike, do you experience the
need
to increase pitch down trim after increasing the airspeed?
Anyway, my speculation is that the stab on the Elite may well be too
small
... and modifying the elevator tips as Mike mentioned earlier may well
be
the best fix ... that is, for those who haven't already cut down the
elevator horns as we all have done to date. For those (like me) who
have
... well that's a topic for another day.
Cheers, Bob 612e
-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com]On Behalf Of
Mike Betti
Sent: Saturday, March 31, 2007 9:15 AM
To: rebel-builders@dcsol.com
Subject: Re: [rebel-builders] Elite flying....Al H.
The control surfaces have the 5 degree angle built in them. At 0 flap
setting, I set up the bottom of the forward surface to be level with
the
wing. That puts the trailing edge of the control surface in 5 degrees
reflex. Where is it ends up on the cabin doesn't matter at that point.
I am not too concerned about this characteristic, just not a good
plane to
fall a sleep in :(
I think the RV's have a simular situation. Might be a good question to
that
group.
Al, CG is at 11.92 aft empty.
Mike
----- Original Message -----
From: "Bob Patterson" <beep@sympatico.ca>
To: <rebel-builders@dcsol.com>
Sent: Saturday, March 31, 2007 9:51 AM
Subject: Re: [rebel-builders] Elite flying....Al H.
cojones toHi Mike !
The pictures on your site show the flap/fuselage box
well below the top of the fuselage - that's why I thought
that was the 'zero' position. If you DO go negative
from there, the box will still be at the lower position.
The reason I think it will affect handling is that a
big part of the handling/stability issue with the Elite
comes from the powerful vortex that comes off the
flaps - particularly the ends. That's why I was
wondering if an outboard end spill plate might help ...
and maybe an inboard one, as well.
Perhaps you could try Al's 'pulse test' with different
flap positions - might improve things a bit - especially
negative... The Elite was designed to cruise with the
built-in negative (about 5 degrees) from having the box
even with the top of the fuse.
With the mods you have done, reducing the width of
the horns, and rounding the leading edges, it will be
MUCH better than the original ! As Al said - "It
certainly got your attention !" :-)
--
......bobp
http://www.prosumers.ca
http://bpatterson.qhealthbeauty.com
http://apatterson2.qhealthzone.com
-------------------------------orig.-------------------------
On Saturday 31 March 2007 12:07, Mike Betti wrote:Bob,
I have the negative flaps and ailerons.
Mike
----- Original Message -----
From: "Bob Patterson" <beep@sympatico.ca>
To: <rebel-builders@dcsol.com>
Sent: Friday, March 30, 2007 10:33 PM
Subject: Re: [rebel-builders] Elite flying....Al H.
Hi Al !
One thing that might be making Mike's a bit different
from yours - he didn't line up the trailing edge of the flaps
with the top of the fuselage, as the original design was.
This means he lost the benefit of negative flaps & ailerons.
That could be contributing to the tendency to nose
over, in spite of having rounded tips on the elevator horns ...
I wonder if adding a 3" (above & below) plate to the
outboard end of the flaps might have any effect ...
Since you can't close up the gap between flap & aileron
sections like you can on the Rebel.
Plate would be pie-shaped ....
Just a thought ..........
--
......bobp
http://www.prosumers.ca
http://bpatterson.qhealthbeauty.com
http://apatterson2.qhealthzone.com
-------------------------------orig.-------------------------
On Saturday 31 March 2007 01:51, Alan Hepburn wrote:
I
of
measured
very
By
why I
don't
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