Hi Ferg,
I'm just now working on installing my mass balance tower and getting the stabs
correctly aligned. My problem is that even before installing the tower, with the
weights contacting the pitch push rod, I only get 12.8 deg. of trailing edge
up pitch. When I trial fit the tower, I get 9.6 deg trailing edge up and 6.5
deg trailing edge down. These measurements are when using the incidence setting
block. Should I use something else? I must be doing something wrong in my
measurements.
Anyone who wants to throw in on this is welcome.
Thanks,
Dan Bish
A144
Tucson, AZ
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Ferg wrote...
However, just before fitting on the fuselage top, I took a last-minute
test of stab travel and found that in intervening months the range of
travel
had reduced for some reason - and I got but 2.8deg nosedown and 11.6deg
Noseup travel! The trim travel works well, but the stab itself has reduced
.
As well, I found the counterweight travel did not allow full noseup
travel, and I had not cut the trim slots long enough to permit full
travel.
I lengthened the slots 1/8inch and the slot problem receded.
It was obvious I had failed to centre the TP18A swivelling rear end of
the counterweight arm to allow the arm to descend slightly into a happier
area, so I removed the two AN-3 bolts at the back and swivelled the TP18A
four turns shorter [1/8"]. Too much!
So I calculated the ratios of TP18A turns (32thread) to front end
travel
of the counterweight and degrees of stab travel. At 2" +/- between aft
bolts
and 30" length of applicable c/w arm I figured one turn [1/32" travel] of
TP18A equalled 1/2" change of countertweight position, and THAT equalled
2deg of stab position.
I'm wondering if anyone else ran into this condition, and whether my
calcs gibe with another's. If all is well, I will increase the travel of
the
big pitch push rod to permit a greater range of stab travel [12deg to
-4deg
in the book].
Any comments gratefully received.
Cheers, Ferg
A064
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