Gilles,
Sounds like your manufacturer, DYN, cheaped out on his choice of
components. A Futaba 9001 has only 54oz of tourqe - I sure wouldn't use it.
On my system I use a Servo with 106oz of torqure. I also use a Custom
Electronics servo tester that has the proper features. When power is
applied the servo dosen't move, but stays in its last position. If power is
lost the servos stays in it's last position. Simple, easy, quick - plus it
has ben Flight tested on many Europas now flying.
I have no idea what a DYN Aero mc4s (or whatever is) but I am sure glad I
built a Europa!!
Best of luck
Bob Jacobsen
A131
>From: "Gilles.Thesee" <Gilles.Thesee@ac-grenoble.fr>
>Reply-To: europa-list@matronics.com
>To: <europa-list@matronics.com>
>Subject: RE : Europa-List: roll trim tab and servo installation
>Date: Fri, 14 Nov 2003 10:21:07 +0100
>
><Gilles.Thesee@ac-grenoble.fr>
>
>Hi all,
>
>Please pardon me to jump in. My present project is not a Europa but a Dyn
>Aero MCR 4S four seater, with a Rotax 914.
>However we share many common concerns and maybe sonebody could ben
>interested by our experience with trim tab servos.
>
>The factory provided us with a system not unlike the one described in this
>thread : a Futaba S 9001 RC model servo and a command box, to be connected
>to the Ray allen stick grips. The command box is said to be derived from a
>servo tester.
>
>After installation, we found several shorcomings in the setup :
>- The servo only holds position when the ship's power is on.
>- When switching the Master on, the servo quickly goes to full travel
>before
>going back to the assigned position.
>- Several builders reported erratic uncommanded trim tab movements in
>flight
>at altitude.
>- Others reported interference problems with the strobe wires.
>- No provision was made for end-of-travel switching.
>
>Our opinion was there's more to the system than just a small servo tester.
>On a fairly fast light plane, the trims must behave in flight , and
>uncommanded movements are unacceptable. Besides, in case of power failure
>the tabs MUST stay put. Besides the Rotax alternator really lacks in
>output,
>and we'd rather not to tax it permanently for a sedom used system.
>
>So we trashed the whole system and bought a RAC T4-5 servo and a tiny
>double
>NAIS relay big as a sugar lump. Although the travel is rather short, the
>tests proved satisfactory :
>
>- No power, no movement possible
>- No stick grip input, no movement.
>- Limit switches are included
>- No pulse signal to be interfered with.
>- Away with the printed cuircuit and 70 gram box.
>
>Flight tests are still ahead, for we still have the Rotax 914 to install
>and
>rads and intercooler ducts to design.
>For what it's worth,
>Regards
>
>Gilles
>Grenoble, France
>Wirng and systems 95% complete and smoke tested
>
>
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