Dan Bish wrote:
>
>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
>
>-------------------------------------------------
>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
>
>
>
>
Dan,
All it took to get A055 into shape was to lower the stop on the
containment about 1/4". Travel is now +14 and -5. As stated earlier,
adjustment of the mass balance arm will add to one direction and
subtract from the other...
--
Jeff - A055
Builders Log: http://www.N55XS.com
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