|
The GX-2 Summer 2006 - Mast Construction - |
|
Page 3 of 4 |
|
The GX-2 mast is a double tapered 2-3/8 x 9 x 20 mast built by vacuum bagging layers of fiberglass over a foam core and wood spared substructure. Initially, six layers of fiberglass will be laid up and then deflection tested. Final tuning will be done by adding appropriate layers of fiberglass to obtain our target deflection ratio of approximately 90 pounds per inch ( measured while supporting the mast at the base and hound). The mast cross section measures 2-3/8 inch x 9 inch from the base up to the hound (station 165) and then tapers 20% fore to aft and side to side for a final dimension of 1-11/16 x 6-3/4 at the top of the mast (station 240). The forward spar is basswood and measures 2-1/4 x 1/2 x 20; the rear spar, which is not much more than a holder for the aluminum luff tube, is basswood with ash ends scarffed on the top and bottom for strength for the halyard pulleys and boom hardware. Anticipated final sailing weight of the mast is 28-29 pounds. |
|
Routing the luff tube on the rear spar |
|
Cutting the taper on the rear spar to match the luff tube |
|
Luff tube mounted; foam glued to 3, test lay-up of vacuum bagged mast glass on foam. |
|
Cutting the foam into stations and hot wire cutting on the jig |
|
The top-sides cut out |
|
Cutting out for the spars |
|
The cutting guides and hot wire power supply |
|
All the foam pieces cut out (notice the tapers) |
|
Checking the taper alignment and overall layout. |
|
All of the pieces were gathered up and weighed (including all hardware) and, without fiberglass, the mast weighs 14 pounds at this point of construction. Fiberglass and epoxy should bring the total sailing weight to just under 30 pounds. |