The Murphy Builders Site

I've noticed an "interesting" characteristic of my Elite, and am curious
to know if others have seen it, and if it also exists on the Rebel or
Moose, and if perhaps it is unique to the floatplane configuration.

From level flight, if you jab the stick back, then release it, the nose
continues to pitch up for several seconds, before returning to slightly
below the trimmed position, then back to level flight. If you jab it
down, the nose continues to pitch down. This continued well above the
yellow arc, at which point I took control again and levelled off. The
whole thing happens quite slowly, so is easily contollable, but I'm
pretty sure this kind of divergent behaviour wouldn't be tolerated in a
production airplane.

Comments?

Al Hepburn




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Is there a lot of friction in your elevator cables? Any chance the elevator
is not returning to neutral after the pitch down?

Scott

-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Alan
Hepburn
Sent: Sunday, October 02, 2005 7:26 AM
To: rebel-builders@dcsol.com
Subject: Pitch Stability

I've noticed an "interesting" characteristic of my Elite, and am curious
to know if others have seen it, and if it also exists on the Rebel or
Moose, and if perhaps it is unique to the floatplane configuration.

From level flight, if you jab the stick back, then release it, the nose
continues to pitch up for several seconds, before returning to slightly
below the trimmed position, then back to level flight. If you jab it
down, the nose continues to pitch down. This continued well above the
yellow arc, at which point I took control again and levelled off. The
whole thing happens quite slowly, so is easily contollable, but I'm
pretty sure this kind of divergent behaviour wouldn't be tolerated in a
production airplane.

Comments?

Al Hepburn





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Al,

I've only heard that divergent pitch behavior, is an Elite "feature" that
the elevator horn mod (halving them) will (or is supposed to) cure. Did you
cut your elevator tips in half?

Mine are still per factory kit ... but plan to do the mod ... find it
interesting that the behavior persists even with the mod. Perhaps something
else needs to be done too ... ??

Having yet to fly in an Elite, I have no input to your post ... but I'm most
interested in reading comments from any Elite drivers out there on this
subject. I have a friend who flies a Rebel, and maneuvering it around from
the right seat, it few well in all three axis. Also right seat flying a
Moose (Paxia's) both on floats and on gear I observed the same ... both
aircraft flew quite well. In fact I remember saying to Al while we were
flying around the Libby airport: "If my Elite flies as good as your Moose
does, I'm gonna be one very happy camper".

Bob 612e

-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com]On Behalf Of
Alan Hepburn
Sent: Sunday, October 02, 2005 7:26 AM
To: rebel-builders@dcsol.com
Subject: Pitch Stability


I've noticed an "interesting" characteristic of my Elite, and am curious
to know if others have seen it, and if it also exists on the Rebel or
Moose, and if perhaps it is unique to the floatplane configuration.

From level flight, if you jab the stick back, then release it, the nose
continues to pitch up for several seconds, before returning to slightly
below the trimmed position, then back to level flight. If you jab it
down, the nose continues to pitch down. This continued well above the
yellow arc, at which point I took control again and levelled off. The
whole thing happens quite slowly, so is easily contollable, but I'm
pretty sure this kind of divergent behaviour wouldn't be tolerated in a
production airplane.

Comments?

Al Hepburn




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Bob:

A have the clipped stabiliser tips, but can't personally comment on handling
vs. the unmodified version, as the only unmodified one I've flow had a down
spring on the elevator to try to make it lest sensitive.

I gave Mike Wiebe a ride today, and he comments that, relative to the Rebel,
it is more responsive in both pitch and roll. He said he has on occasion
just about run out of both on the Rebel (the former when approaching slow,
and the latter in gusts on takeoff), and he found the elite much superior in
that respect (now that'll draw some comment I bet!). In normal flying,
you'd only notice this pitch divergence if you went to sleep, as it's quite
gradual, but if you sit back and let it happen it sure gets your attention.
Mike said he'd never seen so much ground in the windshield! And shows every
sign of accellerating right on through Vne, though we didn't let it go that
far.

If anybody can explain what's going on aerodynamically, Id' like to hear.

I also gave my FBO a ride (7,000 hr float driver), and he commented that
there's too much friction in the rudders. I agree. For a start, I'm going
to put pulleys at the cabin/tailcone direction change, and see how much that
improves the situation. Unklike inspectors in W. Ontario, mine did not
mention this, but I think those guys may well have more than just a
theoretical point.

BTW, subject to a climb test, I now have approval for 2,200 lb gross, thanks
to the Email from Keith saying the Montana floats are designed for that
number.

Al





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Scott:

Good point. I'll put a mark on the cable and another on the floor, and see
if that's what's happening. There is some friction due to these fairleads
along the cabin floor. It's nothing like a pushrod system, but far better
than the rudder loop.

I also notice that, at least in today's configuration, we were cruising with
abut 5 degrees up elevator. Any comments on whether that's normal? That's
with two up and of course the amphib floats. Cruises about 97 kts. It may
just be what it takes to support the floats.

Al





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Al, I completely spaced it that you are on floats, that could have something
to do with it I imagine. It will be interesting to see what other guys on
floats tell you.

Scott

-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Alan
Hepburn
Sent: Sunday, October 02, 2005 6:19 PM
To: rebel-builders@dcsol.com
Subject: Re: Pitch Stability

Scott:

Good point. I'll put a mark on the cable and another on the floor, and see
if that's what's happening. There is some friction due to these fairleads
along the cabin floor. It's nothing like a pushrod system, but far better
than the rudder loop.

I also notice that, at least in today's configuration, we were cruising with
abut 5 degrees up elevator. Any comments on whether that's normal? That's
with two up and of course the amphib floats. Cruises about 97 kts. It may
just be what it takes to support the floats.




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Besides you Al, are there any other (flying) Elites on floats on this
e-group?

Bob 612e

-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com]On Behalf Of
Scott Aldrich
Sent: Sunday, October 02, 2005 8:39 PM
To: rebel-builders@dcsol.com
Subject: RE: Pitch Stability


Al, I completely spaced it that you are on floats, that could have something
to do with it I imagine. It will be interesting to see what other guys on
floats tell you.

Scott

-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Alan
Hepburn
Sent: Sunday, October 02, 2005 6:19 PM
To: rebel-builders@dcsol.com
Subject: Re: Pitch Stability

Scott:

Good point. I'll put a mark on the cable and another on the floor, and see
if that's what's happening. There is some friction due to these fairleads
along the cabin floor. It's nothing like a pushrod system, but far better
than the rudder loop.

I also notice that, at least in today's configuration, we were cruising with
abut 5 degrees up elevator. Any comments on whether that's normal? That's
with two up and of course the amphib floats. Cruises about 97 kts. It may
just be what it takes to support the floats.




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