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Re: Europa-List: EZ-TRIM Altitude Hold PCB

Subject: Re: Europa-List: EZ-TRIM Altitude Hold PCB
From: Jos Okhuijsen <josoke@ukolo.fi>
Date: Sat, 14 May 2005 01:01:37

Hi all,
Just to change the key of the song song and get some relativation. Hate to  
do that, but i also feel kind of responsable if i did not say what i think  
needs to be said. Apart from not liking the idea of "soldering iron  
handicapped" fellow builders to work on flying controls with complications  
they do not grasp, there are some facts to be considered.

On sun and fun i have been talking to almost every autopilot producer for  
experimentals. Both digitrack and trio do a simple attitude hold. Both use  
an extra servo. Both told me things i had not considered before. Both sell  
for a price which is a multiple of the thing we are talking about here.  
Why? Does the competition not work or?
Imho,
1: The ray allen trim motor is probably just good enough for trim. I  
wonder if it has the reserves to fly the plane.
2: EZ-trim has had problems in the software, it is very difficult to get  
the software working without hunting or undershooting. Once there is a  
more or less stable situation, changes in the flying characteristics will  
not readjust the adjusting cycles. That was the main reason the Dutch  
abandoned the idea.
3: There is no insane command override other then the pilot. If, say  
because somebody opens a vent, hence pressure increase, hence correction,  
the plane ends up in a nose high attitude with 40 knots airspeed, it will  
still try to pith up.
4: There is no cut out on turbulence, insane commands might follow.

Ok, let me have it <grin>

Jos Okhuijsen



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