Come on Folks... Attaching the Elevator correctly is NOT that difficult!

[Bob Kuykendall]

Originally Posted by Jamie

A frequent problem I see is the bearing jam nuts being loose. This transfers a lot of load to the nut plates instead of the spars.

That can be a serious issue. The nut plates are just held in with two tiny rivets. Once those rivets get loose it allows a bunch of the type of play that is conducive to flutter.

[Mel]

Originally Posted by jdeas

Building the tail is one of the first steps in what for most is a multi year build. Most of us get better with time and tend to forget some of the issues we deferred for a later date or more information early on.
Perhaps DARs should insist on seeing a proposed yearly inspection plan and suggest that it be performed before their first visit?

All included in the regulations!

[Lars]

Originally Posted by F1Boss

Now, maybe I figured this out as I built one after another aircraft, or maybe it was in a previous job, which also required a succession of things to align...

First, you have to understand that while the QB parts you are using are very good indeed, they do carry with them 'production tolerances'. This particular lesson comes from building many non-QB assemblies. So:

Build sequence: H stab, then elevs. Right?

Build requirement: the elevs have to fit the stab, and operate freely. Duh? Maybe not, esp to one who might be new to a/c assembly. So, how ya gonna make sure the build requirement is met, in the easiest manner?

Fit the spar w/root rib and horn to the stab before building these bits into an elevator. Shim as required (likely, at the center bearing). Now you can proceed with the elev assembly, as the bearing centers and overall length of the spar are not gonna change to any measurable degree.

When I wrote the F1 assembly manual, I included these production tolerances in my plan (past experience/School of Hard Knocks), so I have the fellas install the bearings to the elev spars (1st, install doublers/nutplates etc), fit the steel brackets to the bearings (tightly), and then use the spar to set the locations/centerlines of the brackets on the stab spar. This process eliminates any tolerances due to bearing locations, and sets the tip rib clearance. Once the brackets are drilled & riveted to the stab spar, the builder is to re-attach the elev spar to the stab and bolt the horn to the center bearing, using the indicated washers. The horn is drilled to the elev spar LAST, while everything is in place, again, eliminating 'production tolerances'.

Seems a similar process could be used with the QB parts supplied with the Vans kits? Sure would make life easier! Tell me if I'm wrong!

Another end-around fitting and re-fitting the elevs to get things right would be to do this fitting on the bench, before the stab/elev assy is bolted to the fuselage. Shot bags on the stab will keep the parts from bouncing off the floor....gravity is the one thing that ALWAYS works!

Have a great Thanksgiving!

Carry on!
Mark

Wow, do I wish I had had that to read before I started, longer ago than I care to think about. Well done. Would have saved me a lot of time and headache.

Happy Thanksgiving to you, too!

[sailvi767]

As someone very ignorant about the entire build process but trying to learn what is the best way to check the work on a existing aircraft? I am very comfortable that the builder (Robbie Attaway) did a great job but would still after reading this thread like to get mine looked at and checked out. From what I have read in this thread I don't feel that I can do the inspection myself unless there are some easy key areas to focus on and check. Is there a inspect the elevator for idiots primer out there somewhere? I know I am going to need pictures!

George
(lacking knowledge in Charlotte!)

[Walt]

Originally Posted by sailvi767

As someone very ignorant about the entire build process but trying to learn what is the best way to check the work on a existing aircraft? I am very comfortable that the builder (Robbie Attaway) did a great job but would still after reading this thread like to get mine looked at and checked out. From what I have read in this thread I don't feel that I can do the inspection myself unless there are some easy key areas to focus on and check. Is there a inspect the elevator for idiots primer out there somewhere? I know I am going to need pictures!

George
(lacking knowledge in Charlotte!)

The easiest way to check that the elevator is adjusted properly is to just make sure ALL the bolts are tight and that the elevator moves freely, you should barely have to push on it to cause it to move down and it should coast back to it's "up" postion on it's own accord.

And as brought up previously, always check the jam nuts to be sure they are tight.

[billdianne]

[quote=Walt;599125]The easiest way to check you should barely have to push on it to cause it to move down and it should coast back to it's "up" postion on it's own accord.

With or without the pushrod connected?

[Walt]

[quote=billdianne;599158]

Originally Posted by Walt

The easiest way to check you should barely have to push on it to cause it to move down and it should coast back to it's "up" postion on it's own accord.

With or without the pushrod connected?

With the pushrod connected.

[schristo@mac.com]

Consider that an auto pilot servo will add significant drag to the idea of 'coast'

Even more drag from stick boots and seat cushions...

[Walt]

Originally Posted by schristo@mac.com

Consider that an auto pilot servo will add significant drag to the idea of 'coast'

Not sure what AP you are using but none of the ones I have worked with (TT & S-tec) add any noticable drag to the system. When I get done adjusting an elevator it will coast down with an autopilot servo attached.

[Rivethead]

A hint: When I set up my elevators I used a length of steel rod run through each set of bearings. That would be one rod through three bearings. By doing that I was able to get a visual alignment of the bearings, when the rod looked straight I knew I was getting close. I just kept pulling the rod out and making adjustments until I hit perfection. Perfection being an even hinge line gap between the elevator and stabilizer and zero resistance to movement of the elevator.