Elevator up & down travel

[Mike53]

I will have to join what I am assuming is a common problem for some Onex owners.
I have no idea how one would accurately measure for the 25 degree up and down travel using the cord line of the stab so I have measured from the top of the stab as per plans and after grinding as much as I am willing to from the horn and even a little from the bracket where the upper arm of the horn was contacting it and can only achieve 165 degrees where it calls for 160 degrees to achieve the 25* up travel.
Down travel is not an issue and is 27*.
Has anyone achieved 25* (160* measured from top of stab) up travel by simply grinding material from the horn?
Apparently 18 degrees is all we require according to Tech Support so I guess I will settle for 20*
Thanks .
Mike Turrell Onex 080

[onex0127]

Mike , I was only able to get 20 on my aircraft but the factory said 18 would be okay.

Roy Taylor

[Mike53]

Thanks Roy.It's a bit frustrating to follow the plans ,and considering everything is pre drilled ,to come up short of the design ideal.
Something is not right in Peoria :(
Mike

[thomasjones42]

Ground my first rudder horn to the point of discomfort and then bent with a torch. Got to around 19 degrees from the flat. Didn't like the looks of the horn at that point and ordered a new part. Measured one in the interim that has been flying without problems for a couple years and it was 14 degrees up from the flat. With minor grinding got to 17+ degrees with the new horn and quit.

Tom Jones
Onex #133

[Don_P]

Here are a couple of suggestions for fellow Onex builders having trouble with the elevator up deflection. These, however, only solve the deflection problem up to the point of mounting the vertical stabilizer, as there will be additional clearance problems after that. As suggested on the drawing, I ground down the up deflection stop on the elevator horn's pushrod arm, removing about 1/8 inch of material. (Taking off more than that will cause the pushrod plate to extend out beyond the stop.) Next, in order to provide clearance for the nut and the head of the AN4 bolt (the one that holds the pushrod to the horn), I cut notches in the Upper Fuselage Attach Angle, ONX-T08-13. (Would have posted a photo, but I see the board quota has been exceeded.) The notches keep the bolt head and the nut from striking the underside of the angle before the stop strikes the vertical leg of the angle. Doing these two things achieved an upward deflection of about 20 degrees (measured through the centerline of the elevator). This, however, was prior to putting the vertical stabilizer in place. Builders will discover that doing this will pose clearance problems near the root rib of the stabilizer. To attack that problem, I will be turning the root rib attach angle over, relocating the attach bolts and cutting other chunks out the tail post as necessary. Messy work. By the way I contacted Kerry Fores about the up deflection problem, and he said that flight testing had shown that 18 degrees up worked well for the Onex. Based on this. I hope to achieve at least that much with my planned mods to the vertical stabilizer.

[SonexEZ]

I just noticed my elevator is not even left and right side off 1/4 " has anyone else had this problem
I didnt build this sonex so i am not sure it can be changed now

[gammaxy]

I have a hard time understanding almost all of your posts. Are you saying the trailing edge of one elevator is 1/4" higher than the other? If not, explain where/how are you measuring the 1/4"?

It would be pretty difficult to build it with the trailing edge of one 1/4" higher than the other since the horn and root ribs should all be clamped together against a flat surface during initial assembly. I guess one elevator might have a little extra twist, but from your description, it is impossible to tell what you are talking about.

As far as affecting flight characteristics, I imagine it would probably give you an imperceptible amount of roll and a similar amount of extra drag. I probably wouldn't try to fix it.

[Concorde]

Check your end caps and see they're straight.

[13brv3]

When I recieved my second set of root ribs (which I did not use) and new rudder horn, I noticed that these new root ribs were not pilot drilled.

Tom Jones
ONEX kit 133

Thanks for all the details Tom. FWIW, my kit is #191, and the root ribs are not pre-punched. They must have realized those holes were causing an issue with the up travel. I'll hedge my elevator horn forward a bit as a precaution, since more up is always better than more down when it comes to elevators.

Cheers,
Rusty