Sounds like I need to move to Snomoish WA and join EAA chapter 84. James
certainly answered my questions.
   Does anyone have details on what the tabs would look like? I suppose one
on the elevator (I already have a little electric trim tab) and one on an
aileron. I have always wanted an autopilot but have been unwilling to pay
the price.

On Fri, May 15, 2020, 10:23 James McGauhey via KRnet <>

> I think the trim tab concept is to simplify installation.  If your control
> cables work fine and are adjusted properly, then one train of thinking is
> to not mess with those.  Adding small trim tabs is a simple thing to do
> without messing with your controls.  That said, most autopilots do work by
> installing along the control cables.  One system uses a bar often used at a
> horn, another sister ribs another cable to the control cable and the new
> one goes around the servo with a capstan.  Either is designed so you can
> override by manual control and they don't mess up your original control
> cables.  If something happens, like the loop comes off the capstan, the
> original controls still work fine.  I was going to build a KR, but changed
> to a Zenith CH-650 with full Dynon system and we have two servos for
> autopilot.  One of each kind.  The bar or rod type and the capstan type on
> elevator.  They've worked great for 2 years now.  The autopilot controls
> are built into each Dynon screen, just add servos and calibrate.  Dynon
> servos are about $750 each, total $1,500, which I think is a lot for
> servos, but the total is cheap for a full autopilot system.  Other brand
> servos can be used.
> As for balancing a prop, I'm wondering maybe you balanced by weight, but
> is there a chance the twist is a bit different for each blade?  There is a
> dynamic prop balancer, and I know some in KR land have them as it was used
> at the Oregon gathering a few years ago.  Our EAA Chapter 84 in WA has one
> in the tool crib.  They cost $1,200 to $1,500 (for the cheap ones, shop
> type are $4k+).  Having a shop do it is often about $400 to $500.  Our
> chapter charges $20 but it is only available to members and then only with
> supervision by a member with experience.  Belonging to a EAA Chapter with a
> good tool crib is very valuable, even after your build is complete.  We
> also have very high quality aircraft scales in our chapter, as well as
> swaging tools, a vinyl cutter, a 3D printer, and more.  We want to add a
> cable tensiometer as this is often a one time use when setting control
> cables in a build.  All these items are typically used only a few times
> during a build and generally not worth buying as an individual.
> Jim McGauhey
> Prez, EAA Chapter 84
> Snohomish, WA
> -----Original Message-----
> From: Gary Sack <>
> Sent: Thursday, May 14, 2020 11:52 PM
> To: KRnet <>
> Subject: KR> Two questions
> I've enjoyed the comments concerning the autopilot. My question is: could
> the servos drive springs attached to the control cables. This has been done
> in aircraft for pitch trim and works pretty well. Seems simpler and more
> aerodynamic than trim tabs that work opposite of the desired result. Either
> way, I am interested.
>    Second question...a year ago I wrote about damaging my KR prop while
> hand starting. I have repaired the prop and statically balanced it, but it
> vibrates badly. Is there a simple way to dynamically balance a prop? Also
> does it matter how the prop is orientated to the throw of the crankshaft? I
> know the engine is fine because my spare prop runs smoothly.
>    I took Richard's advice to mount a Subaru starter on my HAPI  engine. I
> had some problems getting the adapter plate just right, but my engine
> really cranks now. Thanks.
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