I recently made the tool Todd describes, copying the one provided by Cobra
for the 26E and adding some minor features. The "alignment tool" is made
from black Delrin plastic rod, about 2" OD. The head end has three 1/2"
holes drilled perpendicular to the tool main axis and at 60 degree spacing
around the head so the handle can be easily inserted in any of 6 positions.
The holes are offset from each other so they just clear one another as they
pass through the center of the rod.
The next step down diameter, adjacent to the head, is a few thousands
smaller than the spar bushing ID to provide a snug slip fit. The length of
this section is almost two bushing widths to allow it, once the spars are
pulled into alignment, to pass through one bushing and enter the next almost
all the way.
The final step down end pin is turned eccentric on the lathe and is small,
perhaps 3/4" OD so it will still enter the misaligned spars, as Todd
mentions, the outside of this pin has to be on the same plane as the OD of
the previous larger section. For strength, a 1/2" hole is center drilled in
the eccentric end pin and all the way into the main body of the tool. A 1/2"
steel rod (I used SS) is pressed flush into this hole and should be a snug
interference fit, but not so tight as to weaken the plastic. (I used a
hydraulic press to seat the pin.)
I added an index mark (drill depression - fill with white paint) on the tool
head so to tell were the eccentric pin is when the tool is inserted. This
helps as one can turn the tool by hand, feel for resistance and thus
determine exactly which way the wing dolly needs to move.
Even though the tool head has 3 indexing holes providing 6 handle positions,
I plan on making a 30 degree bend to one end of the handle. Thus, by
reversing the tool handle I can increase the possible insertion positions.
The current 60 degree spacing is okay, but my O2 bottle is mounted above the
spars and sometimes gets in the way.
--
bumper
"Dare to be different . . . circle in sink."
to reply, the last half is right to left
"Todd Pattist" wrote in message
...
"tango4" wrote:
One of the chaps at our club has a heavily tapered aluminium pin that he
fits into the mainpin slot of his ventus. The major diameter is somewhat
less than the mainpin and the tip diameter about 1 cm. By rocking the
tapered pin the last half inch pops into place very easily. He then
removes
the Ali pin and pops the mainpin in. Every time I help him to rig I swear
I
will turn up a similar pin for my Ventus Bt but never get round to it.
I've got a Ventus, and fortunately, it assembles with ease.
My personal opinion is that I'd be uncomfortable using a
"heavily tapered pin" and rocking it to draw the wings
together. This process would place a relatively high load
on the edge of the bushings that the pin fits into. Doing
that repeatedly might tend to break the bond holding the
bushings in place.
If I needed to draw the wings together, I'd use the tool
I've seen that has the end of the pin turned cylindrically
to a smaller diameter with an offset (but parallel) axis.
(One side of the pin is smooth and the other side has a step
at the tip to the smaller diameter cylindrical tip.)
When you insert this pin, the offset lets the smaller
diameter end enter the second bushing fully (provided the
pin is turned correctly). You then rotate the assembly pin
180 degrees and it pulls the wings together. The force is
applied over the entire bushing.
Hope that was clear.
Todd Pattist - "WH" Ventus C
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