[NSRCA-discussion] Twin elevator servo issue using Futaba 9 ZAP- off list

[Anthony Romano]

Don't know about any Brand F stuff but some radios don't transmit their best 
resolution on the gear channel.

Anthony


>From: "Peter Pennisi" <pentagon.systems at bigpond.com>
>Reply-To: NSRCA Mailing List <nsrca-discussion at lists.nsrca.org>
>To: <nsrca-discussion at lists.nsrca.org>
>Subject: Re: [NSRCA-discussion] Twin elevator servo issue using Futaba 9 
>ZAP- off list
>Date: Fri, 11 Aug 2006 00:55:40 +1000
>
>
>
>Hi Jim,
>
>Thanks again for your detailed responses. I really appreciate them.
>
>My ATV settings are almost identical within 2-3 points of each other and 
>the
>geometry is fairly close as well.
>
>I have spent the last 3 hours trying to get it as close as possible but I 
>am
>not happy with the setup especially at 1/2 elevator throw. The difference
>between both elevator halves is quite noticeable which sort of explains the
>aileron work load during all the looping segments of the P07 schedule which
>are mostly performed at 1/2 elevator stick travel in my case.
>
>I might try one of those match box thingy's which the IMAC guys use to gang
>servos. This will certainly establish wether it is a Futaba associated
>problem with delayed processing to slave channels. At least this way there
>will be no master or slave as the device itself will do all the matching.
>Therefore everything should be relative.
>
>
>Regards,
>
>Peter
>
>-----Original Message-----
>From: Jim Woodward [mailto:jim.woodward at schroth.com]
>Sent: Friday, 11 August 2006 12:29 AM
>To: 'Peter Pennisi'
>Subject: RE: [NSRCA-discussion] Twin elevator servo issue using Futaba 9 
>ZAP
>- off list
>
>HI Peter,
>
>I just went through this same ordeal in early July and spent hours trying
>different ways to resolve it.  What I found was that the only way to get 
>the
>transition points to match (as good as possible) was to have the ATV equal
>or within less than 5% percentage points of each other.  Use the subtrim to
>get the servo arms 90 degrees to the pushrod.  Subtrim did not seem to
>affect throw.  However, different end points definitely affected the
>transition tracking. My control horns were 6/32 screws, so I adjusted the
>clevis' to get the best final throw, then used the smallest ATV adjustment
>possible to get the closest actual endpoints, while using long sticks
>pointed at the end of the rudder.  This worked pretty good but was not
>perfect.  Literally, I spend HOURS over several nights trying to get this
>perfect.
>
>The other thing I noticed was that if there if your elevator 1/2s are not
>perfectly flat (IE, there is some "airfoil" roundness still present on the
>elevator), you have no way to guarantee that the flat sticks are starting
>from the same position, really.  I then installed my "Budd" Laser meter on
>each 1/2, and found that while the "sticks" seemed to indicate things were
>OK, the laser meter indicated a different story.  So then I wondered, how
>can I guarantee than I am installing either of them "perfect" to each 
>side??
>On ailerons it really doesn't matter, but for elevators it does....
>
>I'm really not sold on the dual elevator servo setup. I used FUT 9650 
>servos
>and channels 2 & 5 for the deal.  If I was not weight critical on the
>electric plane, I would have installed a "Jomar" servo reversing Y
>connector.  These offer "centering" on the servo that is getting reversed.
>Also, one servo threw a little more than the other. I ran out of time to 
>try
>to "match" servos.  The whole thing was a mess and I haven't flown the 
>plane
>yet.  It is close but I tell ya, my "eye" was in the end about as good as
>the measuring equipment I had on hand.  If you stand behind the plane and
>see the way light hits the surface, you actually get pretty damn close.  My
>friend Juan clips on one of those Gator cloths-pin angle deflection gauges
>to each 1/2 and calls it a day.
>
>Let me know what you come up with!
>
>Thanks,
>Jim
>
>
>
>
>-----Original Message-----
>From: nsrca-discussion-bounces at lists.nsrca.org
>[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Peter 
>Pennisi
>Sent: Thursday, August 10, 2006 10:06 AM
>To: 'NSRCA Mailing List'
>Subject: [NSRCA-discussion] Twin elevator servo issue using Futaba 9 ZAP
>
>
>  I am using a twin elevator setup (for the first time) in my current F3A
>bird. I am having some servo tracking issues which I can't resolve. All 
>end-
>points and sub-trims have been adjusted perfectly however when I place some
>long extension pins (6 inches) on my elevator halves directed back to the
>centre of my rudder I notice one side leads while the other lags. At half
>elevator stick the throws are different but the end points line up
>perfectly.
>
>What are you guys doing to get this exact (if you can?)
>
>I have one channel plugged into the elevator channel while the other is in
>the gear channel. I am using the Ailevators function on the radio and
>configured as suggested.
>
>
>Thanks
>
>Peter
>
>
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