X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 29 May 2011 17:24:38 -0400 Message-ID: X-Original-Return-Path: Received: from elasmtp-galgo.atl.sa.earthlink.net ([209.86.89.61] verified) by logan.com (CommuniGate Pro SMTP 5.4c3j) with ESMTP id 4997703 for lml@lancaironline.net; Sun, 29 May 2011 16:53:08 -0400 Received-SPF: none receiver=logan.com; client-ip=209.86.89.61; envelope-from=colyncase@earthlink.net DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=dk20050327; d=earthlink.net; b=gTBprMZi+PMuQNK+r1X3z8HIonswQPPIGeI+8csO2boDM3J+YFtP8rVxtwTNoX1A; h=Received:From:Mime-Version:Content-Type:Subject:Date:In-Reply-To:To:References:Message-Id:X-Mailer:X-ELNK-Trace:X-Originating-IP; Received: from [216.57.118.194] (helo=[192.168.1.100]) by elasmtp-galgo.atl.sa.earthlink.net with esmtpa (Exim 4.67) (envelope-from ) id 1QQmyN-000522-CE for lml@lancaironline.net; Sun, 29 May 2011 16:52:31 -0400 From: Colyn Case Mime-Version: 1.0 (Apple Message framework v1082) Content-Type: multipart/alternative; boundary=Apple-Mail-19--169847804 Subject: Re: [LML] Re: Change the speed of the ROC servo for trim X-Original-Date: Sun, 29 May 2011 16:52:30 -0400 In-Reply-To: X-Original-To: "Lancair Mailing List" References: X-Original-Message-Id: <11F4B181-B5B2-4C12-BF2E-52F780BAC6E7@earthlink.net> X-Mailer: Apple Mail (2.1082) X-ELNK-Trace: 63d5d3452847f8b1d6dd28457998182d7e972de0d01da9401ff41b0f21e8cd67332f3d41bea99a5e350badd9bab72f9c350badd9bab72f9c350badd9bab72f9c X-Originating-IP: 216.57.118.194 --Apple-Mail-19--169847804 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=windows-1252 why not buy the speed controller from Ray Allen? It's calibrated, = tested, adjustable, and they've heard over the years from many users. = They also have a nifty 28v -> 12v converter that's just enough to run = the trim system, if you don't already have a 12v supply on your = airplane. Colyn On May 29, 2011, at 4:47 PM, paul miller wrote: > Jim, I had that issue. Lancair avionics put a 200k pot in series in = the original installation back in 2004. I have a 28v airplane driving = the 12v Ray Allen servo. You might have something different? I thought = it never worked because 98% of the pot travel results in the pitch trim = being fully off. But I found that there is a very small range where = there is speed control so that's where I'm at now (about 25% of the = original speed). It takes a few seconds to trim out pitch now--before = it was the "bump". The autopilot behaves much differently now without = huge bumps as it captures an altitude (Tru-Trak). >=20 > If I get the chance later, I will probably swap out the 200k for a = fixed value and I'm guessing it should be something in the order of a = few ohms. It will be important for you to test any lower voltage = setting at altitude and have the ability to recover from a bad setting. = If you drive the trim at a lower voltage than rated it can work on the = ground but might not be sufficient to work in the flight levels leaving = you with no electric pitch trim. Best way to start is time the full up = to full down time trim speed and work from there. I went from 6 seconds = to about 25 seconds. >=20 > Some day I'll add the pitot switch to further numb the trim speed at = cruise and wick it up a bit for approach. Ultimately, a PWM setup is = best and then there are no altitude concerns. >=20 > Paul=20 > Legacy=20 >=20 >=20 > On 2011-05-29, at 8:32 AM, Jim Nordin wrote: >=20 >> I know this has been discussed before and I=92ve given a cursory look = on the archives. But is there a simple way of adjusting / changing the = speed of the servo to slow it down some for pitch trim in a 4PT? The = pitch change is too fast at speed where just a small bump has too much = effect. >> Jim >=20 --Apple-Mail-19--169847804 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=windows-1252 why = not buy the speed controller from Ray Allen?   It's calibrated, = tested, adjustable,  and they've heard over the years from many = users.  They also have a nifty 28v -> 12v converter that's just = enough to run the trim system, if you don't already have a 12v supply on = your airplane.

Colyn

On May = 29, 2011, at 4:47 PM, paul miller wrote:

Jim, I had that issue. =  Lancair avionics put a 200k pot in series in the original = installation back in 2004.   I have a 28v airplane driving the 12v = Ray Allen servo.  You might have something different?  I = thought it never worked because 98% of the pot travel results in the = pitch trim being fully off.   But I found that there is a very = small range where there is speed control so that's where I'm at now = (about 25% of the original speed).   It takes a few seconds to trim = out pitch now--before it was the "bump".  The autopilot behaves = much differently now without huge bumps as it captures an altitude = (Tru-Trak).

If I get the chance later, I will = probably swap out the 200k for a fixed value and I'm guessing it should = be something in the order of a few ohms.   It will be important for = you to test any lower voltage setting at altitude and have the ability = to recover from a bad setting.   If you drive the trim at a lower = voltage than rated it can work on the ground but might not be sufficient = to work in the flight levels leaving you with no electric pitch trim. =  Best way to start is time the full up to full down time trim speed = and work from there.  I went from 6 seconds to about 25 = seconds.

Some day I'll add the pitot switch to = further numb the trim speed at cruise and wick it up a bit for approach. =  Ultimately, a PWM setup is best and then there are no altitude = concerns.

Paul 
Legacy 
=


On 2011-05-29, at 8:32 AM, Jim Nordin = wrote:

I know this has been discussed = before and I=92ve given a cursory look on the archives. But is there a = simple way of adjusting / changing the speed of the servo to slow it = down some for pitch trim in a 4PT? The pitch change is too fast at speed = where just a small bump has too much = effect.
Jim

= --Apple-Mail-19--169847804--