Vic,
Sage advice from the builders. Generally the bushes don't lie. You are
definitely on the right track.
The foot wells are terribly crooked, the seat back better, but not spot on.
You are best not to use them on the Classic. If you want to find out where
the level originally was, measure across the belly just about where the
seatback bulkhead is and that is going to be very close to the bushes. The
fuselage was molded with the belly (and floor) flat. Of course things get
warped, filled, bowed, etc. The plane flies off the bushes so if your plane
is laterally level there, you are off to a great start.
I have rebuilt a couple of Classics and am on the third now in the shop.
Step one is to rig the plane and tail planes and look at it. Does it look
straight. Level the plane off the belly. Initially, check the wing sweep,
dihedral, and incidence before you start gutting or installing mod 52/74.
You can easily see where the wing spars are but you must look close. Use
the spars for placing the level on for dihedral (port aft, stbd forward
edges) and place the level on the same distance out on each side. Then mark
out from the fuselage sides a point at least where the ailerons end along
the spar (about 130 inches) for sweep as the TE is not to be trusted.
Measuring back from the leading edge is OK, provided the angle of the T
square is the same and the fuselage is ish level... Record everything.
De-rig the plane and see what needs to be done.
If the plane is finished painted you have no centerline marks and you don't
know if the top is on straight. For lateral measurements, as I said, I
measure across the belly, then across the bushings ( you will have to make
equal spacers above the bushings, or bolts through them, to get your level
to rest undisturbed above the old cockpit module), and only for future
reference, measure across the back and foot wells. Measure your tailplane
torque tube on both sides, then use a plumb bob to hook over the top of the
fin (rudder removed) and eyeball the vertical. Do your best to get the
plane level across the belly and the longitudinal axis along the door sill,
then do the bushes and the rest. Generally, it is difficult to get the
cockpit module off level. However, it is easier to have it cocked off the
firewall, and that makes for sweep problems. I put a reference mark for
level on the seat back or foot wells, shimming with washers and bolts to
mark level for Wt. and Balance computations. Longitudinal centerline is
---From the gear mount, half way between the pivot bushings. Strike a string
to the center of the tail. Then, it is off to the tail plane torque tube.
Once you are comfortable with all the measurements, if you are within a
tenth of a degree it is not worth the trouble to try to change the dihedral
which is set by the cockpit bushes.
Sweep should be within an 1/8" but try for perfect. Incidence should be
equal. There is a lot of filling in the area at the root. I will measure
the incidence at the root, 2 foot out, then at the MAC or about where the
ailerons and flap split is. The 2 foot and MAC are the two I'd like to see
equal. See my website for how to trim.
I have spent as much as 450 hours and $20,000 US rebuilding, painting and
finishing one and when done, was worth every penny. Classics are light and
with an XS firewall forward quite fast. Building or rebuilding an aircraft
is a process of discipline and tolerance, which like a child growing,
delivers great pleasure in the future.
Regards,
Bud Yerly
--------------------------------------------------
From: "fraser221" <vicflett@tiscali.co.uk>
Sent: Saturday, December 06, 2014 9:32 AM
Subject: Europa-List: torque tube
>
> i am working on restoring a classic mono to flying condition and in the
> process of changing the tp11 bushes for the torque tube.
>
> i have checked the levels at 3 different points, the wing spar bushes, top
> of footwell forward of the firewall and on top of the seat module behind
> the headrests (on uncarpeted surface).
>
> i get a similar reading between the spar bushes and the footwell tops but
> quite different on the seat module.
>
> is this a problem or am i right in thinking that the spar bushes should be
> the one to use?
>
> hope someone out there can assist.
>
> Vic
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=435414#435414
>
>
>
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