Within the context of this thread, I note that there has been little discussion
of the relative alignment of the tailplane to the wing. I found that after
bonding
in my cockpit module, one edge was slightly higher than the other. (We're
talking about 1 degree here) This led me to consider that the spar bushings
would not therefore be level, and in fact they were off slightly, consistent
with the positon of the module.
My suggestion is to place a 1/2" bolt into each spar bushing in the module,
supporting
two pieces of metal/wood of equal length, allowing support of a cross
member placed on top of them which would be positioned above the headrests. A
level can be placed on this piece to verify condition, and if the crossmember
is long enough, it can be used to sight across the top to verify the
'parallelness'
of the stab cross tube with the alignment of the wing bolts.
Interestingly, after 4 hours of time spent marking the hole position for the
stab
cross tube, they resulted almost perfectly on the cross hair marks, and the
whole assembled affair is pleasing to the eye.
There is enough flexibility in the tail fin to allow setting perpendicular to
the
stab when bonding on the top of the fusulage. The important issue here is
that the flying surfaces are all square and we have assumed that the cockpit
module
will always sit properly because the fit seems so correct.
Said differently, not previously discussed recently (that I've been able to keep
up with) is the assumption of wing position, which is based upon the location
of another component not necessarily positioned consistently with the 'gunnels'
of the canoe.
Cleve Lee
A198 Mono XS
Detroit, MI
On Tue, 20 November 2001, Tim Ward wrote:
>
> Shaun,
> I had your problem in its entirety! The most important two thing is to;
> 1. Ensure the Torque Tube is horizontal with the front of the airframe!
> 2. Ensure the distance from the front of the airframe to the end of the
> torque
> tube on each side is equal!
> Then the aircraft will fly straight in both Lateral and Vertical planes.
> I opted to leave the inherent twist in the canoe as these measurements COULD
BE
> altered once the jig holding the
> canoe in place is taken off or the aircraft may tend to revert back to its
> twisted "natural" state. Debatable I know, however
> the result of the twist, if left in, is small (in my case) and can be covered
> cosmetically to ones satisfaction.
> Cheers,
> Tim
>
>
>
>
> Shaun Simpkins wrote:
>
> > All right, this is getting confusing and putting my SHORTS in a twist.
> > If I go out and measure my raw fuselage bottom, the port stablilator
> > fairing is at most 1/8" forward of the starboard fairing.
> > The port torque tube crosshairs are 1/8" higher than the starboard
> > relative to the tops of their respective fairings, but are equally far aft
> > of the nose of the fairings.
> > I haven't checked the waterline, nor the vertical displacement of the
> > fairings from the waterline. Let's assume that they are the same for
> > now. If there is no twist and you drill on the crosshairs, your stabilators
> > willwind up with the port end skewed forward and up, and the port root
> > 1/8" higher than the fairing. If there's a twist, it could be horizontal,
> > but
> > still out of line with the fairing and still vertically misplaced.
> > Untwisting
> > a pure longitudinal twist could make things worse, since the crosshairs
> > are misplaced vertically.
> > So from what I see, the proper procedure would be to:
> > 1. untwist the tail cone ( and hope that the twist is purely about the
> > longitudinal axis ) if warranted.
> > 2. measure aft equal distances from the firewall for the torque tube
> > centers.
> > 3. measure up equal distances from the waterline for the torque tube
> > centers, but adjust to equalize any misalignment with the fairings.
> > There's another argument about whether twisting to align the tail is bad
> > from a structural point of view...
> >
> > Shaun
> > A207
> >
> > ----- Original Message -----
> > From: "Miles McCallum" <milesm@avnet.co.uk>
> > <europa@avnet.co.uk>
> > Subject: Re: Tailplane to root fairing alignment, -and servo
> > pins
> >
> > > Longitudinal position is fine - vertical position isn't - if you "untwist"
> > > the tail end in a jig...
> > >
> > > M
> > >
> > > > Forwarded from the bounce bin. Message is from
> > > > "Cliff Shaw" <dm25shannon@home.com>
> > > >
> > > > ****************************************************************
> > > >
> > > > All
> > > >
> > > > I just went out in the shop and made a mesurement on my taleplane torque
> > > > tube. It is 141.5" from the front surface of the fire wall to the front
> > > > surface of the torque tub at its outboard end. Both P & S sides are
> > > exactly
> > > > equal. My installation was done on the scribed X points. It turned
> > out
> > > > right on the MONEY and I am happy.
> > > > Cliff Shaw
> > > >
> > > >
> > > >
> > >
> > >
> >
>
> --
> Timothy P Ward
> 12 Waiwetu Street,
> Fendalton,
> Christchurch,
> NEW ZEALAND
>
> Ph. 0064 03 3515166
> email ward.t@xtra.co.nz
> Mobile 025 2649325
>
>
>
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