Jib anchoring system bonding process !
ClaudioD
All forward supports are mounted and OK, now is time to take care about the backward supports !
The crossing beams are just supporting the transversal servo beam during bonding and ensuring the horizontal level
ClaudioD
Hi Row, I went checking what I could do about the use of a “Jib trimmer”.
Although very possible, see drawing below, the gain is around 33g.
The trim with the HS5245 servo is limited to 13mm sheet length variation that in turn provide an angular jib boom adjustment around 3.2° from any set angle.
What I loose is that using only one winch like Eurgle, its power is not adequate for 76/78dm².
My initial choice remain valid for the dual winch option, the first is that the sail area is split on two winches providing more power control under strong winds, and second, being the two servos winches independents, any angular choice can be made.
My idea is to link, anyhow, mechanically the two joysticks, main and jib, and use only the trim function of the jib to adapt the sailing angle. I do not know if I have expressed correctly the principle.
Cheers
ClaudioD
Claudio. I have an ec 12 and I use the jib adjustment similar to what you have diagrammed. only my servo is mounted such that the arm is vertical in the hull and rather than just using the servo horn I added a small carbon rod about 2" long.
I use the RMg wing, but when I get home I’ll take a look at what servo I have for the jib trim. as it is a standard size servo, but is metal geared and so far for 3 years have been handling 2 cell lipo with no adverse affects. I installed a new pot on the TX that I can control with my left index fingertip. I know I am able to adjust the trim on the sail by nearly 2" in any weather.
I’ll take the control board out and take a pic and post later today…
Thank you very much Marc.
The actual situation is that the only powerful servo winch is the RMG capable to handle easily 78dm& sail area. The drawback is that this type of model is still too heavy unless I will relax the specifications. The two servos I use now are the ‘eurgle type’ very close in weight to the RMG And work hard to keep down the weight, further I need money to buy one !
As said above, to handle the sail area with the eurgle, I decided to split the functions : Main & Jib. By doing that I realized that the jib could be controlled continuously if desired with the independent winch. If only the TX trim would be used I assume that some cm become availables even not necessary.
The other solution is to use the “servo arm” sufficiently powerful like the HS-7950TH for 68g. This servo is expensive: ~150$ with Servocity.
In this case, as you said, one servo arm + a servo trimmer will cover the need. Question of money !! and grams !!
I suppose that with the EC12, you don’t have weight problems as I have with the 123.
Keep waiting your pics, thank you
Cheers
ClaudioD
Still at work…
but yeah the Ec12 is a portly gal at 20+ lbs… but with 1200 sqinch of sail it is very comparable to the 122
I use the 7955 in my soling. but I think I’m using futaba in the ec12 for the jib adjustment along with the RMG I need to get a second RMG for my “rescued” ec12… prices are high, but they are a quality product…
I’ll get the info and measure the amount of jib travel and take some pics…
Almost finish the hull, servo set up check, paint primer, hull wet sanding and final assembly.
While still below 4050g at the moment, the next operations may cost some additional 40g ! If this is the case, I will loose my
bet ! of course two servos are used, while with the single “arm servo” the bet is won !!!
ClaudioD
This morning wet sanding for 2 hours.
The weight dropped by 20g. Taking into consideration that the primer was composed of 3 coats, I assume that the paint will be weighting some 35g deck included instead of 50g as from budget allocation.
Started some hardware like the servo rudder links for 9.70g including servo horn. A little too heavy, I shall find something else !
Because the 6 brass Eye-bolts were weighting 10.5g, I decided to make them out of available profiles sitting in a corner of my lab !
I used both brass ‘L’ profile a ‘U’ aluminum profile reduced to an ‘L’ profile. (‘L’ Aluminum profile not available at this moment).
Interesting to observe that the aluminum self-made brackets are weighting 5.90g against the 10.5g of bought brass eye-bolts.
A new option for the servo rudder links is going to weight 6.90g against the actual of 9.70g.
The above will let spare 7.2g. Is almost nothing compared with 4050g , but each bit if properly analyzed, at the end will count more then expected.
Thus, one day work to gain 15g from paint and 12.8g from eye-bolt and rudder links = 27.8g , half of the battery cells !!.
I’m the grams fighter ! sorry is the professional deformation from 35 years of space technology !!!
ClaudioD
PS:
the rudder links are now 5.65g thus better then 6.90g as expected. Carbon tube of 3mm and carbon rod of 2mm. The carbon tube was drilled to bring the internal diameter to 2mm as the carbon rod !
CD
Last night I went to the overall budget updating.
At present the boat weight is 4029g, but deck bonding not included as well some other small details.
Based on the present experience, I have elaborated the points that can be made better in order to achieve ‘comfortably’ the 4000g +/-50g and projected further the exercise for the future 123 model ‘flat deck’.
1 - the actual hull is rater sturdy and heavy therefore the next lamination can be made lighter then 218g, including glass reinforcements if the female mold is used (better surface finish and less wet sanding). Using carbon tissue of 93g/m² mixed with 0.8g/m² glass as :
0.93 x 2 x 32dm² = 59.52g (internal layer)
0.80 x 2 x 32dm² = 51.20g (external layer)
0.93 x 2 x 20dm² = 37.20g (reinforcements)
total hull weight = 148g ( - 68g) against 216g
2 - balsa stern not needed
3 - samba stripes 3x3 instead of 3x5
4 - 2 winches substituted by 1 servo arm and servo trim for the jib - 100g against 130g
5 - smaller servo rudder - 24g
6 - lighter receiver - 9g
The achievable weight reduction with careful material choice is about 96g and the overall boat weight could be even lower then 4000g !!!
The image below show the weight update a future projection :
ClaudioD
How to get the sheets crossing the Roof ?
I told to replace the classical tubes with cross perforated Latex Membrane.
It may be possible also to use two parallel sheets of Latex with small overlap, I shall try tomorrow !
If the Latex will not wear out, the system will be rather sealed !
The ‘problem’ come from the fact that the traveler string is also joint coupled with the main and jib sheeting strings.
BTW, I tried to glue the latex on a piece of glass lamination with cyanolyte ‘super glue’ and resisted quite well to the “pull test”.
The ribbon was elongated about 30% before starting to loose adhesion !
Here some pictures about
ClaudioD
playing with Latex single and double sheet with cross cuts at 90° and turned at 45°
The visible small hole is 2mm diameter
ClaudioD
Hello Claudio,
I guess the latex will act as a water dropplets scraper. BTW, I don’t remember you mentioned the material of the sheeting strings.
Sylvain
claudio,
here are pics of the sheeting arrangement for the ec 12 and the entire board removed.
I get 4" of jib adjustment, the arm on the jib trim is 2" long.
futuba 3305
Modulation: Analog
Torque:
4.8V:
99.0 oz-in (7.13 kg-cm)
6.0V:
124.0 oz-in (8.93 kg-cm)
Speed:
4.8V:
0.25 sec/60°
6.0V:
0.20 sec/60°
Weight: 1.66 oz (47.0 g)
Dimensions:
Length:
1.57 in (39.9 mm)
Width:
0.79 in (20.1 mm)
Height:
1.50 in (38.1 mm)
Motor Type: 3-pole
Gear Type: Metal
Rotation/Support: Dual Bearings
[QUOTE=marcsmith;64608]claudio,
here are pics of the sheeting arrangement for the ec 12 and the entire board removed.
I get 4" of jib adjustment, the arm on the jib trim is 2" long.
Thank you Marc !
I see the trimmer arm is rater long compared with the normal horn. It happen to you to make full use of the trim with 2" adjustment ? If yes in which occasions ?
The 3rd question is in your picture below!
Cheers
ClaudioD
The Latex membrane single sheet is in place !
ClaudioD
Claudio,
I see that you do not have the edge hull/deck finished off yet. Are you going to use just a sand paper and filler of some kind? I did it on my NSS 650 and it didn’t come out any good, so I am going to have to play with it some more. That’s why I am asking so I can avoid such delay on my next boat.
Can’t wait to see your boat painted.
Regards,
Lukasz Koch
PS hope you don’t mind that I will copy your latex idea
Hi Lukasz,
Once the deck will be epoxy bonded, the sheer line will be trimmed with a manual cutter, filler if needed and finished with sanding paper before painting,
The latex idea for the moment is only an idea, waiting to see if will work during sailing without significant wear out.
Up to you if you wish to copy it !
Cheers
ClaudioD
To day I did very little !
I was training myself on the way to install the sheeting strings through the roof hatch.
It will be very probable the necessity to open another hatch in front of the mast to locate the battery .
This is due to the second servo for the jib, place generally used for battery and receiver.
For the transmitter I added the ribbon spring on channel 3 that will be the Jib joystick. Since I lost the ATV adjustment (ch.1)
I need to control carefully the number of revolutions needed for the jib and relying on the trim for fine adjustment.
ClaudioD
Claudio,
I think I can answer your 3rd question -
The pole that you can see runs up to the forward end of the boat and has a turning block attached to it for the sheeting loop. It’s a very simple and extremely good idea that enables the sheeting loop to be replaced easily if it snaps/jams etc. If you look closely at Marc’s 4th picture I think the detail will become apparent.
Like your thinking with the latex membrane and can’t see why it wouldn’t work - the only negative I can think of is that it might need to be easily replaced.
Regards,
Row