Sunday, May 17, 2009

New Gantry Construction, part 1

Yesterday I began building my new gantry. The objective is to incorporate a 5 degree forward cant and an improved splash down fairing. My model is the Mach2 gantry pictured in a recent post by Felix Schulte (see below.)



Even though I admire the socket-type attachment that Amac has designed, my new gantry will need to attach as my existing one; I do not plan on redesigning the rear rack saddles or the gantry attachment points.

I started with some fiberglass tubes and epoxied on a carbon sleeve. The wetted down sleeve is nicely drawn onto the base tube with some heat shrink tubing, activated with a heat gun. I chose the glass tube for flexibility and the reduced likelihood of catastrophic failure versus the stiffer (but more brittle) all carbon tube. Besides, an equivalent carbon tube is quite a bit more expensive. The sleeve provides a bit more strength and stiffness and nicely goes with the carbon look of the deck.

My existing gantry was used to create a form to duplicate the critical top angle of the gantry (critical because the new gantry had to fit in the space of the old one.) The pix below show the existing blue gantry and the form I built around it and the new tubes placed in the form. The timber brace is only temporary and will be removed once the joints are reinforced.





Once the top triangle was out of the jig, I placed the vertical tube with its five degree forward angle. Tomorrow I should build the lower diagonals. The mid line tension member (with its bottle screw course adjustment) will be placed a couple of days later. Lastly, I will build the fairing.



Stay tuned.



Boats to Build, Jimmy Buffett

It's time for a change
I'm tired of that same ol same
The same ol words the same ol lines
The same ol tricks and the same ol rhymes

Days precious days
Roll in and out like waves
I got boards to bend I got planks to nail
I got charts to make I got seas to sail

I'm gonna build me a boat
With these two hands
It'll be a fair curve
From a noble plan
Let the chips fall where they will
Cause I've got boats to build

Sails are just like wings
The wind can make em sing
Songs of life songs of hope
Songs to keep your dreams afloat
I'm gonna build me a boat
With these two hands
It'll be a fair curve
From a noble plan
Let the chips fall where they will
Cause I've got boats to build

Shores distant shores
There's where I'm headed for
Got the stars to guide my way
Sail into the light of day

I'm gonna build me a boat
With these two hands
It'll be a fair curve
From a noble plan
Let the chips fall where they will
Cause I've got boats to build.

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