Steve,

 

Well, it depends........ If you got a standard kit with the optional hardware package circa 1989, you would have received black anodized aluminum brackets with a distance of 4 inches when bolted to the bottom of the elevator's [-shaped center forward spar to the push-rod mounting hole. 

 

However, the hinge point is at the top of that style elevator and that adds 2.5 or 3 inches to the "arm".  Thanks to Rob, the light bulb came on and I have to retract the statement that the change represented 25% in force and throw.   If one measures from the hinge line, the arm went from about 7 inches to 6 inches when the bracket hole was moved 1" (or 6.5 to 5.5).  Perhaps I should drill another hole to shorten it further, as long as the push rod doesn't engage a bulkhead or the elevator through the full range of the elevator. Uh, I don't think I will since the pitch stick force is already pretty heavy in a 2G pull and my pitch system, including trim, system is balanced quite nicely right now.

 

If you got the MKII center hinged elevator, the arm may be of a different length and finish, but yielding similar results --- or maybe not.

 

The 200 and 300 series Lancairs have the most options and modifications of any kits I have ever seen...... And you want an exact measurement without specifying the details of the elevator system?

 

I know nothing about when Lancair changed the bracket or how it was changed.  In any event, the kit date is very important.

 

Grayhawk AKA Scott

N92EX 320

 

Hi ALL

 

I think all us new flyers could use the exact measurement from the hinge point to the attach hole. Also what is this bracket made from?  steel ?

 

steve alderman   360   7  TT  and counting

-----Original Message-----
From: rwolf99 <rwolf99@aol.com>
To: lml <lml@lancaironline.net>
Sent: Tue, Mar 6, 2012 5:39 am
Subject: [LML] Re: LNC2 - Harminization between pitch and roll

Bill is right.  Handling qualities are all about stick FORCE. Stick displacement is not the issue, as long as you have enough room to push the stick as far as you need.

 

Moving a pivot point in the linkage closer to the axis of rotation will increase stick force, and also reduce stick travel, for a given elevator displacement (i.e. for a given aircraft response).  The Lancair 320 accomplished this in the 1990's by changing the elevator weldment (the bracket bolted to the elevator that the aft pushrod attaches to). The new weldment moved the attach point 1 inch closer to the axis of rotation (just as Bill said).  But fear not, the earlier guys just drilled an extra hole in their weldment and ignored the original hole.  In principle you can do this anywhere in the system, but it seems to be easiest to implement out at the tail.

 

I have both weldments in my hangar.  The old one is kinda gold, almost as though it were cadmium plated like an AN bolt.  The new one is silver, almost as though it were chrome plated.  But the bottom line is the number of inches away from the pivot point.  If I recall correctly the new one is 2 point something inches away and the old one is 3 point something inches.  (Big help, huh?)  I would have to go to the hangar to check.

 

This mod is fairly benign. 

 

Keeping the CG forward helps, too, but is harder to accomplish.  Moving a battery from behind the seat to the front of the passenger footwell might be worth investigating if you don't have rudder pedals there.

 

- Rob Wolf