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Technical Chat Tips and Advice, including flying the Luscombe

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 #9177  by agp
 Fri May 20, 2016 8:10 pm
Can anyone gove me a figure for tailplane incidence please.


 #9210  by p3stoker
 Sat Jun 18, 2016 12:58 pm
Pretty sure it's -1.5 degrees measured with the horizontal splice plate levelled.

 #9211  by Nige
 Sun Jun 19, 2016 1:27 pm
You might find your answers on previous threads Alan. Good luck.
 #9212  by Barry
 Wed Jun 22, 2016 3:11 pm
I posted this back in 2012:

David, I just did this in March with new elevator cables from the very helpful Doug. I'll go check my emails with him and other docs, but if memory serves, its a loop system so what we did was set the up rig first, check the TCDS but I think it was 33 degrees for my 8F, added one more degree, held the stick back, and took out that one degree with the down cable as it comes up tight and we had correct tension. Then we used the stop bolt for down elevator rig adjustment. There was much discussion on what to reference and building a "trammal bar", but see this below from Doug, also check your phenolic fairleads as if they are worn you may get wear from contact. The slap reference was for side to side stick movement for the aileron cable tension I believe:

From Helpful Doug:
Luscombe horizontal Stabilizer INCIDENCE is specified at -1.5 degrees (EG centerline of leading edge displaced down 1.5 degrees from the splice plate, as measured from the CENTER line of the horizontal stabilizer with a trammel bar.). The tolerance specified is +/- .5, or ½ degree, giving us a rigging range of -1.0 degree to -2.0 degrees on the assembled aircraft.

To the extent there is camber in the stabilizer, it is equal on the top and bottom of the horizontal and vertical stabilizer(s), therefore it has no bearing on the rigging of the controls for movement, and is no way affecting the final outcome of static rigging or control rigging. The effects of ‘camber’ in measuring incidence are eliminated by building a trammel bar that identifies a line parallel to the center of the stabilizer, then measuring incidence as a number from that parallel line, relative to the horizontal splice plate on the fuselage.

Control rigging of the elevator is a rigging of MOTION, relative to the center line of the stabilizer. This is NOT measured relative to the level line of the aircraft. Therefore, this motion and deviation can be measured relative to the trammel bar *, and will remain within specified tolerance in virtually all cases. *one could use the skin as the center point after determining the exact camber definition and adding or subtracting that from the measurement. Personally, I use 6” templates with an obtuse (excluded angle), to set the rigging.

Best of luck!

Barry '48 8F
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 #9214  by Nige
 Thu Jun 23, 2016 4:28 pm
Hope you got that Alan? I believe that to be an as accurate an answer one could hope for!
Thanks guys...