lml@lancaironline.net Mailing List Archive

Steve, Rob, et al

Well, when Rob's light bulb went on it was a CFL and took a day to brighten up. Grayhawk may know his aircraft performance but he should not be trusted with details from 21 years ago...... He often needs help, like the following photos.

First, here is a picture of the elevator half joining [-shaped aluminum bracket with the original aluminum bell crank arms attached. Note they are not affixed to the bottom of the bracket as the befuddled Grayhawk claimed):

Of course, the bracket is upside down and this pic was taken with an old-fashioned film camera after 1321 hours into the slow build process on 5-24-1991.

I found one of the original black anodized arms in my junk box as seen below:

If one considers the fiberglass covering the bracket, the hole to the hinge line distance is about 4 inches. If the hole is moved in by an inch, then the throw and force is changed by about 25% as stated in the original Grayhawk email. Of course, a little trig is required to calculate the actual distance movement at the rod end.

Here is a pic of the "3 inch" arm as it is now installed:

The distance from the bottom of the elevator skin to the center of the bolt is 7/8".

BTW, these recent pix were taken with my I-Phone -- how far we've come!

The wiser Scott Krueger AKA Grayhawk (a strange ancient alter-ego)

PS the black line beneath the nut is not a crack, but merely a scratch in the white paint.

In a message dated 3/7/2012 7:01:16 A.M. Central Standard Time, n5276j@aol.com writes:

Grayhawk,

I do have the black anodized aluminum brackets, also the kit was from 11/1989 #471. I did not buy the kit back then, picked it up years ago and finished it. Measuring it on the airplane it looks like 3" defienty not 4". I don't understand the 2.5" or 3" addition? I have 7 tt and no problem with the pitch not near as bad as a KR2 which I flew for many years and hours.

Rob got my attention when he talked about the different colors which made me think of steel and I thought my was aluminum. It does look like it was change to 3" .

I built in a trim tab (9x3) with mac servo that works almost perfect. Can't quite trim down at full speed flaps reflexed but just a bump on the flap switch fix's it. It does however trim up on approach. I could re-adjust for cruise but would loose approach or build a bigger tab. I think I'll leave it alone.

Was there any problems with the aluminum brackets?

Steve Alderman 360 7TT

-----Original Message-----
From: Sky2high <Sky2high@aol.com>
To: lml lml@lancaironline.net.
Sent: Tue, Mar 6, 2012 12:03 pm
Subject: [LML] Re: LNC2 - Harmonization between pitch and roll

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

In a message dated 3/6/2012 9:31:51 A.M. Central Standard Time, n5276j@aol.com writes:

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