Elite Elevator Sensitivity

[Keith B. Oliver]

I would like to see the photo you refer to
Maybe you could post it to the Elite section online


Keith Oliver
Elite #654 TD
N654ME (reserved)
Farmingdale, Maine




-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com]On Behalf Of
Alan Hepburn
Sent: Wednesday, August 13, 2003 10:35 PM
To: murphy-rebel@dcsol.com
Subject: Elite Elevator Sensitivity


Folks:

I have now flown an Elite on amphibious floats, and can report as
follows:

The aircraft flown had been modified from the Murphy design by adding a
down spring to the elevator cable (picture available for anybody
interested). Without this, the original test pilot reported that pitch
control was unacceptable. He is a 34,000 hour corporate jet pilot, who
flies a clipped wing Monocoupe (kind of like a high wing Gee-Bee) for
recreation, so I'm inclined to believe him.

I found the airplane somewhat sensitive in pitch, but not excessively
so. It did, however, exhibit mild divergence in pitch, which I've never
encountered in flying more than forty types of production light
aircraft, and a few homebuilts. The effect is as follows: in trimmed
cruising flight, when you nudge the sick forward or backward and release
it, the airplane continues to pitch in the original direction, rather
than returning to the trimmed attitude. At first, you wonder when this
is going to stop, and whether the thing would eventually attempt a loop
if left unchecked. However, the pitching stops about 4 degrees from the
initial attitude. A little unnerving at first, but it's quite gradual
and controllable, and the owner quite likes it that way. This may be
due to the floats, but I think not. It does not appear to be due to
friction in the control system.

Reports on the clipped elevator version in Nevada continue to be
positive. My present inclination is narrowing the spades on mine,
though the down spring is certainly by far the simplest approach for
anybody who has already completed the airplane. I think I will go with
Wayne's suggestion of narrowing the spades from the inside, and grafting
on an extension to the horizontal stab. It turns out Murphy included a
couple of extra stab tip ribs in my kit, so this will be really easy in
my case.

While not endorsing the change, the factory do nothing to discourage it.
In fact, I think we will eventually see something along these lines
adopted.

For those interested, Sean also has a rather neat electric pump (marine
source) driving the float hydraulics on the aircraft I flew. I will
certainly go electric on mine, but plan to look into other pumps -
perhaps the gear pump from a Piper Seneca, since the marine pump is a
bit bulky.

Regards, Al



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[Alan Hepburn]

Belated reply, Bob:

I believe you have to shorten the sticks, at least on my vintage of kit
(#587). As it comes, the stick hits the panel with only moderate forward
travel, so I'm pretty sure it will have to have about 2" lopped off to get
the required range of elevator movement. Sean tells me that's what he did
on the two Elites he's built. It' s unfortunate, really, because they did
feel a little on the short side on the Elite I flew. I won't actually cut
anything until I come to rig the elevator controls, but I don't think
there's any other way (at least for male pilots!)

Regards, Al Hepburn

----- Original Message -----
From: "Bob Patterson" <apat@istar.ca>
To: <murphy-rebel@dcsol.com>
Sent: Friday, August 08, 2003 11:19 AM
Subject: RE: Elite Elevator Sensitivity

Hi Keith !

I wouldn't shorten the sticks. It's not a question of
leverage, so much as giving more travel for a given deflection.
We <lengthened> the sticks in the prototype Rebel by over 6" to
reduce the sensitivity to control movements ! The shorter
stick meant very small movements resulted in excessive control
deflections, calling for a delicate touch - as well as increasing
the control forces. Later, the throws on bellcranks, and control
horn lengths were adjusted by the factory to further improve the
Rebel's control harmony - making it a very pleasant aircraft to fly !

In the case of the Elite, even a small movement can cause
a quick reaction from the elevators ....

.....bobp

---------------------------------orig.---------------------------
At 04:48 PM 7/16/03 -0400, you wrote:

Question
Are the sticks being left at factory length ?
I plan to shorten mine depending on force needed for deflection.
It seems to me that the shipped length provides too much leverage
Ideas ? Comments


Keith Oliver
Elite #654 TD
N654ME (reserved)
Farmingdale, Maine




-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com]On Behalf Of
Alan Hepburn
Sent: Tuesday, July 08, 2003 11:18 PM
To: murphy-rebel@dcsol.com
Subject: Re: Elite Elevator Sensitivity


Thanks, Wayne. I'm still undecided as to which way to go. Check #1 is
going to be to fly an Elite and see just how big a problem it is. The

way

Sean describes it, there is just about zero stick force per g, and that
would be unacceptable to me. But it's hard to imagine it could be that

bad.

Maybe we'll hear Bob's opinion when the ramble is over. Sean tells me he
expects the factory to adopt the mod, but we'll see.

I'm currently considering shortening the spades about 25% instead of
narrowing them. Narrowing them presumably reduces the servo moment at

the

hinge by about 50%, thus restoring feel. If you shorten them 25%, the

lift

force will be reduced by 25% (assuming roughly linear lift distribution),
but the arm of the force will also be reduced by 25%, giving a moment
reduction of darned near 50%, while maintaining the full stab/elevator

area,

and the wider spade, which will be more rigid structurally. Of course,

some

more weight would be required.

Any comments would be appreciated.

----- Original Message -----
From: "Wayne G. O'Shea" <oifa@irishfield.on.ca>
To: <murphy-rebel@dcsol.com>
Sent: Tuesday, July 01, 2003 10:51 PM
Subject: Re: Elite Elevator Sensitivity

Alan, I'll just offer my 2 cents and wouldn't it make more sense to

narrow

the tip balancer "spade" (if this is really deemed necessary) from the
inboard edge outward and then use another rib and 4" or so of aluminum

to

lengthen the stab to fill the gap. This will let you keep the full

length

of

elevator, that you may just want to full flare a landing. According to

Bob

P

the Elite needs ALL the elevator it comes with!!

Wayne


----- Original Message -----
From: "Alan Hepburn" <ahepburn@renc.igs.net>
To: <murphy-rebel@dcsol.com>
Sent: Tuesday, July 01, 2003 10:35 AM
Subject: Elite Elevator Sensitivity

Elite

hole

the

of

from

Unfortunately,

some

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[Legeorgen]

Bob,

In my Rebel, I took the control stick to a machine shop and had them bend it
about three more inches so as to miss the panel and be closer to my lap.
Cutting the stick off would work too but you will change the geometry and make the
stick more sensitive as it will be closer to its axes.

Bruce 357R



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[Bob Patterson]

Right on, Bruce ! Later Rebels can order a different
stick for use with the firewall moved back 3" (like the Elite).
These sticks have a bend that moves the top back, while preserving
the length.

In any case, the prototype Rebel stick DID hit the panel -
but this didn't matter, as you never got <anywhere near> needing
that much control deflection in flight !! :-)

....bobp

------------------------------orig.---------------------------------
At 09:58 PM 9/15/03 EDT, you wrote:

Al,

In my Rebel, I took the control stick to a machine shop and had them bend it
about three more inches so as to miss the panel and be closer to my lap.
Cutting the stick off would work too but you will change the geometry and

make the

stick more sensitive as it will be closer to its axes.

Bruce 357R



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