Today's Message Index:
----------------------
1. 07:09 AM - Re: Trim-- electric vs. manual (dedgemon@knology.net)
2. 12:27 PM - Re: Trim-- electric vs. manual (Bill Repucci)
3. 03:24 PM - Re: Trim-- electric vs. manual (Ross S)
4. 11:55 PM - Re: Trim-- electric vs. manual (Gerry Filby)
Message 1
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| Subject: | Re: Trim-- electric vs. manual |
--> RV9-List message posted by: "dedgemon@knology.net" <dedgemon@knology.net>
Guys,
I've been watching the trim thread for a while and have a couple of cents
worth to add.
I've been flying my RV-9A since October and currently have about 56 hours.
I'm flying a O-320-D1A 160HP with a Hartzell and MANUAL trim.
Let me say that the manual trim works beautifully. If you really want
electric thats fine but I'm very happy with the manual, its very precise.
While building the airplane I wondered why Van put such a huge trim tab on
the airplane, after all the 6's tab is only about half the size. Well I
can tell you that in cruise we could use a much smaller tab. Very small
trim tab movements will move the nose quite a bit. It is very typical for
me to just barely touch the trim knob in order to make "very" fine
adjustments. The nice thing about the manual is that its very simple to to
that, just move the knob however fast/slow you need to.
During flight at slow speeds such as during landing the big trim tab
requirment is pretty obvious. As the aiplane is slowed you start making
some pretty large nose up trim inputs, and as the flaps go out you need
quite a bit of up trim as the speed comes down to 65-70 knots. In fact
when flying the airplane solo (fwd CG) I normally will have all of my nose
up trim rolled in by the time I establish on final at 65 knots or so.
Fortunately at these speeds it doesn't really matter if you run out of
trim because the stick is really light.
I probably need to rerig the trim to bias the tab travel a bit toward the
nose up position. Just haven't gotten around to it yet.
Don't know if this helps folks to decide but in summary I really like the
way the manual trim works in flight, its simple, its very unlikely to
break, and if you disable the button you shouldn't have to worry about a
trim runaway or step input.
By the way, I disabled the button by drilling a hole through the shaft
under the button and inserting a cotter pit. That way I didn't have to
take the button assembly apart.
--
David Edgemon
RV-9A N42DE
Message 2
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| Subject: | Trim-- electric vs. manual |
--> RV9-List message posted by: "Bill Repucci" <bill@repucci.com>
Too bad the electric trim doesn't work off the manual cable like some
production airplanes. That way you could still adjust the trim manually
if the actuation motor went Tango Uniform.
Back to the basement for me. Busy drilling and pounding.
Bill
www.repucci.com/bill/baf.html
-----Original Message-----
From: owner-rv9-list-server@matronics.com
[mailto:owner-rv9-list-server@matronics.com] On Behalf Of Carroll
Neblett
Subject: Re: RV9-List: Trim-- electric vs. manual
--> RV9-List message posted by: "Carroll Neblett" <cneblett@erols.com>
I've bought and built the electric elevator trim, but have never
been
fully comfortable with elevator control being subject to an electrical
problem (and the trim servo doesn't appear to be of very impressive
quality).
It may be a stupid idea as I've never seen or heard of it on any
aircraft, but I've often wondered what would be wrong with having
electric
trim on one side and manual trim on the other. This would give the
convenience advantage of electric trim (if there is any) and the safety
advantage of manual trim. In the event of a runaway electric trim, it
could
be offset with manual trim, but I have no idea what the drag and roll
effects would be of having extreme and opposite trims on the left and
right
elevators.
If having both trim types would be aerodynamically practical, it
shouldn't add much cost, especially if Van's would allow the empennage
kit
to be ordered with two "left" elevators.
Carroll Neblett
(waiting on wings)
----- Original Message -----
From: "Richard Scott" <rscott@cascadeaccess.com>
Subject: RV9-List: Trim-- electric vs. manual
> --> RV9-List message posted by: Richard Scott
> --> <rscott@cascadeaccess.com>
>
> For those with flying 9's, I would like to know how the plane flies at
> full
> up and full down trim. Can you keep it level? Can you overcome the
trim
> adequately to climb with nose down trim and vice versa? In other
words,
> if
> you get a runaway trim situation, can you continue to fly safely until
you
> can land, even if that means flying half an hour or more? You can't
in my
> '41 Interstate Cadet, but trim in that is manual.
>
> If it is too hard to overcome the trim, then for me the question of
> manual vs. electric trim is simple: You'll never have a manual trim
> runaway on you (of course the cable could break, but so could wires).
>
> Richard Scott
> 9A wings
>
>
>
Message 3
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| Subject: | Trim-- electric vs. manual |
--> RV9-List message posted by: "Ross S" <rv7maker@hotmail.com>
I installed the electric trim because I didn't want the big knob in the
cockpit and figured the electric would be lighter. .... so for a few extra
bucks it would be win win.
Reality struck when I started flying. In my opinion, the electric is not
nearly as good as the manual.
The electric is not sensative enough to get exatly the correct hands off
pitch position. If you just bump it one direction it goes too far, and then
bump it back and that is too far. I realize that you can buy a speed
control to slow it down, but on the other hand it is already too slow. When
you want to trim for landing or takeoff, it takes an eternity to get into
position. I usually end up coming in hot and don't have time to screw with
it and I land without trimming the plane. It just plain doesn't have the
operational benefits of manual trim.
Solutions:
1.) One of you guys needs to come up with an electric trim with a dash
mountet knob with a fair amount of resistance (maybe like the volume control
on my GMC pickup that has detents every few degrees) that needs to be turned
about ten turns for full deflection.
or..
2.) Make a speed control that will ramp up in speed the longer you hold it
down. Then you could still control it with the coolie switch on the grip,
but you could have fine control and speed both.
-Ross
Ross Schlotthauer
RV-7 flying but not finished
www.experimentalair.com
>From: "Bill Repucci" <bill@repucci.com>
>Reply-To: rv9-list@matronics.com
>To: <rv9-list@matronics.com>
>Subject: RE: RV9-List: Trim-- electric vs. manual
>Date: Fri, 11 Mar 2005 15:26:49 -0500
>
>--> RV9-List message posted by: "Bill Repucci" <bill@repucci.com>
>
>Too bad the electric trim doesn't work off the manual cable like some
>production airplanes. That way you could still adjust the trim manually
>if the actuation motor went Tango Uniform.
>
>Back to the basement for me. Busy drilling and pounding.
>Bill
>www.repucci.com/bill/baf.html
>
>-----Original Message-----
>From: owner-rv9-list-server@matronics.com
>[mailto:owner-rv9-list-server@matronics.com] On Behalf Of Carroll
>Neblett
>To: rv9-list@matronics.com
>Subject: Re: RV9-List: Trim-- electric vs. manual
>
>
>--> RV9-List message posted by: "Carroll Neblett" <cneblett@erols.com>
>
> I've bought and built the electric elevator trim, but have never
>been
>fully comfortable with elevator control being subject to an electrical
>problem (and the trim servo doesn't appear to be of very impressive
>quality).
> It may be a stupid idea as I've never seen or heard of it on any
>aircraft, but I've often wondered what would be wrong with having
>electric
>trim on one side and manual trim on the other. This would give the
>convenience advantage of electric trim (if there is any) and the safety
>advantage of manual trim. In the event of a runaway electric trim, it
>could
>be offset with manual trim, but I have no idea what the drag and roll
>effects would be of having extreme and opposite trims on the left and
>right
>elevators.
> If having both trim types would be aerodynamically practical, it
>shouldn't add much cost, especially if Van's would allow the empennage
>kit
>to be ordered with two "left" elevators.
>
>Carroll Neblett
>(waiting on wings)
>----- Original Message -----
>From: "Richard Scott" <rscott@cascadeaccess.com>
>To: <rv9-list@matronics.com>
>Subject: RV9-List: Trim-- electric vs. manual
>
>
> > --> RV9-List message posted by: Richard Scott
> > --> <rscott@cascadeaccess.com>
> >
> > For those with flying 9's, I would like to know how the plane flies at
> > full
> > up and full down trim. Can you keep it level? Can you overcome the
>trim
> > adequately to climb with nose down trim and vice versa? In other
>words,
> > if
> > you get a runaway trim situation, can you continue to fly safely until
>you
> > can land, even if that means flying half an hour or more? You can't
>in my
> > '41 Interstate Cadet, but trim in that is manual.
> >
> > If it is too hard to overcome the trim, then for me the question of
> > manual vs. electric trim is simple: You'll never have a manual trim
> > runaway on you (of course the cable could break, but so could wires).
> >
> > Richard Scott
> > 9A wings
> >
> >
> >
>
>
Message 4
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| Subject: | Trim-- electric vs. manual |
--> RV9-List message posted by: Gerry Filby <gerf@gerf.com>
Van's own RV9 has the manual trim (and electric flaps) ...
hmmm, wonder why ...
g
>
> --> RV9-List message posted by: "Ross S" <rv7maker@hotmail.com>
>
> I installed the electric trim because I didn't want the big knob in the
> cockpit and figured the electric would be lighter. .... so for
> a few extra
> bucks it would be win win.
>
> Reality struck when I started flying. In my opinion, the
> electric is not
> nearly as good as the manual.
>
> The electric is not sensative enough to get exatly the correct
> hands off
> pitch position. If you just bump it one direction it goes too
> far, and then
> bump it back and that is too far. I realize that you can buy a speed
> control to slow it down, but on the other hand it is already
> too slow. When
> you want to trim for landing or takeoff, it takes an eternity
> to get into
> position. I usually end up coming in hot and don't have time
> to screw with
> it and I land without trimming the plane. It just plain
> doesn't have the
> operational benefits of manual trim.
>
>
> Solutions:
>
> 1.) One of you guys needs to come up with an electric trim with a dash
> mountet knob with a fair amount of resistance (maybe like the
> volume control
> on my GMC pickup that has detents every few degrees) that needs
> to be turned
> about ten turns for full deflection.
>
> or..
>
> 2.) Make a speed control that will ramp up in speed the longer
> you hold it
> down. Then you could still control it with the coolie switch
> on the grip,
> but you could have fine control and speed both.
>
> -Ross
>
> Ross Schlotthauer
> RV-7 flying but not finished
> www.experimentalair.com
>
>
> >From: "Bill Repucci" <bill@repucci.com>
> >Reply-To: rv9-list@matronics.com
> >To: <rv9-list@matronics.com>
> >Subject: RE: RV9-List: Trim-- electric vs. manual
> >Date: Fri, 11 Mar 2005 15:26:49 -0500
> >
> >--> RV9-List message posted by: "Bill Repucci" <bill@repucci.com>
> >
> >Too bad the electric trim doesn't work off the manual cable like some
> >production airplanes. That way you could still adjust the trim manually
> >if the actuation motor went Tango Uniform.
> >
> >Back to the basement for me. Busy drilling and pounding.
> >Bill
> >www.repucci.com/bill/baf.html
> >
> >-----Original Message-----
> >From: owner-rv9-list-server@matronics.com
> >[mailto:owner-rv9-list-server@matronics.com] On Behalf Of Carroll
> >Neblett
> >To: rv9-list@matronics.com
> >Subject: Re: RV9-List: Trim-- electric vs. manual
> >
> >
> >--> RV9-List message posted by: "Carroll Neblett" <cneblett@erols.com>
> >
> > I've bought and built the electric elevator trim, but have never
> >been
> >fully comfortable with elevator control being subject to an electrical
> >problem (and the trim servo doesn't appear to be of very impressive
> >quality).
> > It may be a stupid idea as I've never seen or heard of it on any
> >aircraft, but I've often wondered what would be wrong with having
> >electric
> >trim on one side and manual trim on the other. This would give the
> >convenience advantage of electric trim (if there is any) and the safety
> >advantage of manual trim. In the event of a runaway electric trim, it
> >could
> >be offset with manual trim, but I have no idea what the drag and roll
> >effects would be of having extreme and opposite trims on the left and
> >right
> >elevators.
> > If having both trim types would be aerodynamically practical, it
> >shouldn't add much cost, especially if Van's would allow the empennage
> >kit
> >to be ordered with two "left" elevators.
> >
> >Carroll Neblett
> >(waiting on wings)
> >----- Original Message -----
> >From: "Richard Scott" <rscott@cascadeaccess.com>
> >To: <rv9-list@matronics.com>
> >Subject: RV9-List: Trim-- electric vs. manual
> >
> >
> > > --> RV9-List message posted by: Richard Scott
> > > --> <rscott@cascadeaccess.com>
> > >
> > > For those with flying 9's, I would like to know how the plane flies at
> > > full
> > > up and full down trim. Can you keep it level? Can you overcome the
> >trim
> > > adequately to climb with nose down trim and vice versa? In other
> >words,
> > > if
> > > you get a runaway trim situation, can you continue to fly safely until
> >you
> > > can land, even if that means flying half an hour or more? You can't
> >in my
> > > '41 Interstate Cadet, but trim in that is manual.
> > >
> > > If it is too hard to overcome the trim, then for me the question of
> > > manual vs. electric trim is simple: You'll never have a manual trim
> > > runaway on you (of course the cable could break, but so could wires).
> > >
> > > Richard Scott
> > > 9A wings
> > >
> > >
> > >
> >
> >
>
>
>
>
>
>
>
--
==========================================================
Gerry Filby gerf@gerf.com
Home: 415 239 4846
Cell: 415 203 9177
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