Sanding of plug completed.
A lot of very fine dust, hope the vacuum cleaner will not suffer too much !!
Cleaning with dry tissue only. No water !
Next, coverage with packing tape.
Packing tape applied, one layer only.
While waiting for better weather conditions, lower RH, here a ‘dual table’ about Sail’s & Rig Data used for a Class M model.
Before lamination and for precautionary reasons, I have applied two layers of Wax.
Today I manage to laminate “Wet on Wet” 3 glass - epoxy layers.
1 of 85g/m²
2 of 105g/m².
Notice the second layers just laying on previous laminated one of 85g/m² without adding any epoxy.
The 2nd layer is acting as a sponge absorbing the excess of resin like a “peel-off” tissue.
No need to add too much resin, just what it is needed to cover the full surface.
This is the way I use to keep the overall weight inside the rule of thumb : 50/50.
Similarly for the 3rd layer.
According to my calculations the hull surface is of 40.50dm², therefore :
(0.85g/dm² + 1.05g/dm² + 1.05g/dm²) x 2 for resin = 5.9g/dm² x 40.50dm² of hull = 238.95g .
238.95g is the expected weight of the bare hull out of mold.
Removed the excess of glass-epoxy and let now cooking under the sun 
!!! Close to the Canal du Midi (construction 1666- 1681), and for those who like to knows more : https://en.wikipedia.org/wiki/Canal_du_Midi
the Sun is gone and cloudy and windy again !!
Although only 24h are gone, being impatient, I decided to de-mold the hull with the help of tiny fiberglass blades and hull got away without problems.
The Master is still perfect !
The bare hull weight is 259g instead of 238.95g. Too much resin ? Probably yes but less then the budget allocation !
Now is arrived the moment to draw and cut the hollow shadows to allow hull “setup” assembly.
Claudio,
Coming along quite nicely. Looking good!
Seeing your work makes one want to start another boat project.
Cheers,
Clark
Hi Clark,
apparently I’m progressing without troubles except weather conditions.
Also happy that the balsa mold came out in perfect shape, there was some fear at the begin.
The basic idea to post my “build logs” is to let others to do similar things.
My work is often an experimental one. If the results are good then I can think about a racing model of the kind.
After reading some papers about the performances of a Chine Hull, I decided to make one model to verify what learn.
In the past I did the “Delta Rig” based on 4 panels, a way to make a hull rapidly since the hull was not my major concern at that time.
Today I have chosen a 6 panels Chine Hull after various considerations, in spite of the difficulties to draw a 6 panels hull, that may also explain why there are only few around.
At the begin I drawn the 5 panels and 6 panels Hulls and the choice finally was for a 6 panels.
The attached figure will probably explain why.
In others words, it my understanding is that the 6 panels hull may have some advantages over the 5 panels.
Above 6 panels the hull is getting close to a round hull and probably some chine hull peculiarities are lost.
Since sensitive to the hull draft, the 6 panel is offering the lowest value as well a flat panel during low heeling conditions.
A long flat surface may offer a better lifting like a surf.
Further, the 6 panels exhibit larger surface orientation angles that could better acts as an anti-drift hull.
Of course all that it is simply my opinion and the way I look at, nevertheless open to any other points of view.
Hollow Shadows are drawn and ready for cutting
Cheers
Claudio
I forgot to consider the thickness of the lamination (about 0.55mm) and now I have to rectify the shadows one by one !!!
Only 3 made so far…
As per today ! not very satisfied of the hollow shadow cutting and the manual remedy rather boring. Shimming will be necessary in many places. The important matter now is to ensure that the beam width at each station is the one drawn. Because of the chine form, the edges/corners will ensure the hull form stability.
Actually I’m busy with Polyester putty all over the Fiberglass Hull. One panel at the time and waiting to get it dry.
Found a very efficient abrasive based on ceramic net.
No water needed. see : https://www.mirka.com/en-US/us/abrasives/abrasives/#/ Here last pics
While the polyester is polymerizing, I have anticipated some design work concerning the appendices and Radial boom. I manage also to collect old Fins and Bulbs used on previous models. Unfortunately the only bulb found for this model is a short type one of about 3000g (2920g).
For what concern the Radial Jib Boom for the moment is only a prototype and some parts are under construction like the double box.
Here below the pictures.
I toke an old polystyrene mock-up of a previous Class M Design and used to insert the Radial Jib Boom, see a couples pics. The Jib radial box is not yet made !
Working progress refers to the Electronic Set-Up.
I have some doubts about the type of main servo I should use, Arm or Drum.
The Arm Servo Savox 1256TG is given for 20Kgcm at 6V. At the end of the Arm of 91mm the force available is 20/9.1= 2.19kgcm and 110° swing can be obtained in 0.27".
Care shall be used to avoid damages due to the high speed of the Arm.
The Drum Servo HS-825HB is given for 13.2kgcm at 6V. The Drum ID is 3.8cm therefore the force available is: 13.2/3.8 = 1.73kgcm.
The big handicap is the low speed.
To control the sheet length of 292 mm are necessary 3.42".
A chart/diagram show the Arm Servo and the Pull force needed at the boom sheet anchoring point.
For 15.5 knots of wind against the sail surface of 7200cm²(800sq-in), a force of 0.911kgcm is required with a safety factor of 2.
Finally, the good old Hitec Servo Drum, in this configuration, is still sufficiently powerful to handle 15.5kt of wind, but rather slow.
The drawings show also the electronics positions and weight distribution in order to reach a static equilibrium.
I will probably use for the prototype model the Hitec Servo Drum.
Hard time today ! Sanding the full hull and weight check.
269g, exactly 10g more then at the time of de-molding.
The vertical traces are induced by the inner surface and representing the packing tape overlapping. In principle no problems, but confirmation will be expected from primer spraying.
The Fin and Bulb trial assembly for the first time. The two items coming from different models a class M and “123” projects.
Some interface problems observed that need intervention including the Bulb tilting. The Fin top side will be also modified and some thickness added to cope with the rectangular trunk.
Few hull surface blemishes repaired.
Bottom of Fin modified and search for tilting angle. See before and after.
Smoothing corners lamination to be made.
Two operations this WE.
- Cutting the hull sloped transom. Was not easy on a polygonal form.
I also decided to make a skirt just for fun ! - Bonding samba stringer 7x3mm along the deck sheer line.
Templates of central stations in order to retrace the the wooden supports* including the sloped transom and skirt.
- Not decided yet, it may be balsa crossed sheets and fiberglass/epoxy instead of triplex. Weight will be the criteria !
Set Up as for now. Changes not excluded !
Preparing balsa/glass/epoxy sandwich, 4mm thickness (2 crossed layers of 2mm)
The Balsa sandwich plates with glass epoxy are ready, two types for 2 and 4mm thickness
The support shadow’s installation is started.
Some shadows are repositioned outside the design limits therefore some trimming are necessary. The way I do it is to bond the supposed shadow at the wanted position and then trimming against the hull form with small glued Bristol papers. These ‘new’ shadows shapes will be used to trace them on the Balsa/FBG sandwich plates.
The transom is glued with 5min, epoxy loaded with µballoons, similarly the bow is reinforced with a block of foam. This block will be the contact point for the bumper. Not excluded to adds a wooded shadow inside.