The Murphy Builders Site

Hi Ted !

Maybe, if you have a choice, it might be easier just to
leave the fin centered. Several Rebel builders have found
that to be the easiest solution - easier to build, & make fairings,
and it works fine no matter what engine you choose ....

Whatever offset you use is only effective at one airspeed
and power setting anyway, so a 6" or 8" tab on the rudder would
work just as well.

--
......bobp
beep@prosumers.ca
http://www.prosumers.ca
http://bpatterson.qhealthbeauty.com
http://apatterson2.qhealthzone.com
http://apatterson2.ordermygift.com

-------------------------------orig.-------------------------
On Sunday 25 November 2007 15:26, Ted Waltman wrote:

For those of you flying a Moose with an M-14, what is the offset from
center of the forward tip of your dorsal fin?



Thank you,



Ted Waltman

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Ted; Many of us have built in an electric trim tab system into the
rudder in a similar manor to the elevator tab. I will mount the dorsal
fin centered on the fuselage.

I used the same R C Allen servo as the elevator, but had to open it up
add epoxy filler into the slot to limit the amount of travel by making
the limit switches shut off early. I have pictures available if you
want them. Some builders have used a 4" X 20-24" tab across two bays of
the rudder, and added ribs as needed. I used a 6" X 11" tab (because I
thought it looked right).

My theory is that I will use the rudder cable springs at the pedals to
give me the basic neutral rudder trim in cruise flight. I have built in
adjustment at the springs to accomplish this thru trial and error on the
test flights. I also have added "gap" filler material to both tabs made
of thin aluminum, to enhance the air flow, and make it look better! My
hinges have the hinge section facing to the inside as opposed to the
original on the elevator tab sticking up.

Dick Wampach SR-108



-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of
Bob Patterson
Sent: Sunday, November 25, 2007 9:27 AM
To: rebel-builders@dcsol.com
Subject: Re: [rebel-builders] Moose: M-14; Dorsal Fin offset


Hi Ted !

Maybe, if you have a choice, it might be easier just to
leave the fin centered. Several Rebel builders have found
that to be the easiest solution - easier to build, & make fairings,
and it works fine no matter what engine you choose ....

Whatever offset you use is only effective at one airspeed
and power setting anyway, so a 6" or 8" tab on the rudder would
work just as well.

--
......bobp
beep@prosumers.ca
http://www.prosumers.ca
http://bpatterson.qhealthbeauty.com
http://apatterson2.qhealthzone.com
http://apatterson2.ordermygift.com

-------------------------------orig.-------------------------
On Sunday 25 November 2007 15:26, Ted Waltman wrote:

For those of you flying a Moose with an M-14, what is the offset from
center of the forward tip of your dorsal fin?



Thank you,



Ted Waltman

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Thanks Dick. Yep, I already have the trim tab / motor built into my rudder.
I was just thinking of offsetting my dorsal fin, but after your and Bob's
input, maybe that's not necessary given my trim tab.

Do I understand you correctly to say that your rudder return springs are of
a slightly different length at the pedals? That must have been a bit of a
science project to figure out and adjust!

I'd be interested in pictures of your gap filler on the tabs. If you have
pics send them to me directly please at ted@i1ci.com. We'll have to fly
some formation to see who's plane is faster next summer <grin>.

Ted

-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of
Richard Wampach
Sent: Sunday, November 25, 2007 12:41 PM
To: rebel-builders@dcsol.com
Subject: RE: [rebel-builders] Moose: M-14; Dorsal Fin offset

Ted; Many of us have built in an electric trim tab system into the
rudder in a similar manor to the elevator tab. I will mount the dorsal
fin centered on the fuselage.

I used the same R C Allen servo as the elevator, but had to open it up
add epoxy filler into the slot to limit the amount of travel by making
the limit switches shut off early. I have pictures available if you
want them. Some builders have used a 4" X 20-24" tab across two bays of
the rudder, and added ribs as needed. I used a 6" X 11" tab (because I
thought it looked right).

My theory is that I will use the rudder cable springs at the pedals to
give me the basic neutral rudder trim in cruise flight. I have built in
adjustment at the springs to accomplish this thru trial and error on the
test flights. I also have added "gap" filler material to both tabs made
of thin aluminum, to enhance the air flow, and make it look better! My
hinges have the hinge section facing to the inside as opposed to the
original on the elevator tab sticking up.

Dick Wampach SR-108



-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of
Bob Patterson
Sent: Sunday, November 25, 2007 9:27 AM
To: rebel-builders@dcsol.com
Subject: Re: [rebel-builders] Moose: M-14; Dorsal Fin offset


Hi Ted !

Maybe, if you have a choice, it might be easier just to
leave the fin centered. Several Rebel builders have found
that to be the easiest solution - easier to build, & make fairings,
and it works fine no matter what engine you choose ....

Whatever offset you use is only effective at one airspeed
and power setting anyway, so a 6" or 8" tab on the rudder would
work just as well.

--
......bobp
beep@prosumers.ca
http://www.prosumers.ca
http://bpatterson.qhealthbeauty.com
http://apatterson2.qhealthzone.com
http://apatterson2.ordermygift.com

-------------------------------orig.-------------------------
On Sunday 25 November 2007 15:26, Ted Waltman wrote:

For those of you flying a Moose with an M-14, what is the offset from
center of the forward tip of your dorsal fin?



Thank you,



Ted Waltman

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Ted,

While I have an O-540 rather than the M-14, I would imagine the torque
effect to be similar - though opposite. I asked about offset of the fin
when constructing, and was told by MAM that it was not necessary - thus I
did not offset. I did add electric rudder trim, however. Tab construction
is almost identical to elevator tab though the rudder tab is only about six
inches in length. Used the same Ray Allen servo as the elevator. I ordered
two extra rudder ribs to "box in" the tab area, and fabricated my own spars.
Thus far it has worked perfectly and I'm very glad that I added this trim -
makes for hands-free flight (in smooth air). Only small changes are needed
when changing power settings or speeds - but still handy to have.

Charlie Starr N96CS

----- Original Message -----
From: "Ted Waltman" <tedwaltman@i1ci.com>
To: <rebel-builders@dcsol.com>
Sent: Sunday, November 25, 2007 9:26 AM
Subject: [rebel-builders] Moose: M-14; Dorsal Fin offset

For those of you flying a Moose with an M-14, what is the offset from
center
of the forward tip of your dorsal fin?



Thank you,



Ted Waltman





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