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                           Glasair-List Digest Archive
                                      ---
                     Total Messages Posted Tue 04/27/04: 3
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Today's Message Index:
----------------------
 
     1. 12:20 AM - Re: Glasair-List Digest: 1 Msgs - 04/26/04  (MPPalmer@aol.com)
     2. 08:23 AM - Re: trim  (RiteAngle3@aol.com)
     3. 02:00 PM - Re: trim  (RiteAngle3@aol.com)
 
 
 
________________________________  Message 1  _____________________________________


Time: 12:20:18 AM PST US
From: MPPalmer@aol.com
Subject: Glasair-List: Re: Glasair-List Digest: 1 Msgs - 04/26/04

--> Glasair-List message posted by: MPPalmer@aol.com

Hello:

>  I know there is an electrical way to make the motor stop quickly
>  when the current goes off, but I don't yet have any experience in this 
area.
>  I've read about "magnetic braking" and "DC motor braking",  but I'm not 
sure
>  how to implement this feature.   Suggestions?

The way you make a motor stop instantly is to short the contacts when your 
trim switch is in the off position.  The way the old MAC trim servo folks did it

was to use two microswitches in a pseudo DPDT configuration that would short 
the motor when in the neutral switch position.  (The company changed hands and

is now Ray Allen.  p 387 in current Spruce catalog.)

Know that's not much to go on, but if you can find a MAC switch and copy 
their design, you've got it.  (Or simply use a MAC switch!)

Hope this helps,

Mike Palmer <><
Excellence in Ergonomics






________________________________  Message 2  _____________________________________


Time: 08:23:02 AM PST US
From: RiteAngle3@aol.com
Subject: Glasair-List: re: trim

--> Glasair-List message posted by: RiteAngle3@aol.com

In a message dated 4/26/04 11:56:59 PM Pacific Daylight Time, 
glasair-list-digest@matronics.com writes:
I notice one area that could be improved:  The
motor doesn't stop instantly when the current is cut off.  It "coasts"
briefly. 
Troy:
In my opinion, this is not anything to worry about, the fix would probably be 
more problem than the fixed trim "coasting."   
Many many aircraft the trim doesn't stop immediately, from light production 
aircraft up to Boeings & Douglas.  IF your trim is so sensitive you need to 
stop it that fast, you have it to sensitive, again in my opinion.  After all, it

takes a few seconds for the aircraft to stabilize at the new trimmed speed so 
I think you are having "much ado about nothing."  And, the airloads may be 
such that it won't coast in flight due to the airloads on the tab.  After a few

hours in flight you will never think of it.
Just my opinion from over 40 years as a professional pilot from J-3's to 
B-767's

Feel free to reply off list if you like, I can normally answer same day, 
unless busy instructing students :-)
Elbie Mendenhall
EM Aviation
www.riteangle.com

DO NOT ARCHIVE






________________________________  Message 3  _____________________________________


Time: 02:00:42 PM PST US
From: RiteAngle3@aol.com
Subject: Glasair-List: re: trim

--> Glasair-List message posted by: RiteAngle3@aol.com

--> Glasair-List message posted by: RiteAngle3@aol.com

In a message dated 4/26/04 11:56:59 PM Pacific Daylight Time, 
glasair-list-digest@matronics.com writes:
I notice one area that could be improved:  The
motor doesn't stop instantly when the current is cut off.  It "coasts"
briefly. 
Troy:
In my opinion, this is not anything to worry about, the fix would probably be 
more problem than the fixed trim "coasting."   
Many many aircraft the trim doesn't stop immediately, from light production 
aircraft up to Boeings & Douglas.  IF your trim is so sensitive you need to 
stop it that fast, you have it to sensitive, again in my opinion.  After all, it

takes a few seconds for the aircraft to stabilize at the new trimmed speed so 
I think you are having "much ado about nothing."  And, the airloads may be 
such that it won't coast in flight due to the airloads on the tab.  After a few

hours in flight you will never think of it.
Just my opinion from over 40 years as a professional pilot from J-3's to 
B-767's

Feel free to reply off list if you like, I can normally answer same day, 
unless busy instructing students :-)
Elbie Mendenhall
EM Aviation
www.riteangle.com

DO NOT ARCHIVE