Bearospace Sloop EMMA - Page 5 - RC Groups
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Jan 16, 2018, 10:38 PM
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robcrusoe's Avatar
I set the bulkheads in place with a thin bead of 5 min epoxy first on the join, Doesn't have to be continuous.

We used Sikaflex polyurethane sealant on our first three boats (one Irene, two Emmas) and it worked fine, although smoothing this stuff off was rather messy like G n' S reports with his experiences.
This time I'm using Sikaflex Liquid Nails as it has all the strength these boats would ever need and so long as you shape the bead before it skins, Easy. Some turps on a rag will smooth it off nicely, and clean up, if you do it quickly. Thing to do, try it on some scrap ply first.
It is also about 25% the cost of the polyurethane, about $5 . Hard to get off your fingers, I find.
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Jan 19, 2018, 11:20 AM
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Drill won't fit grrrrrrrrrr


Mistake master here, I make 'em so you don't have to
Do indeed drill the fin trunk before further assembly of the hull...

How I fixed this was to cut bulkheads #2 & 3 apart on both sides to free the trunk from the hull assembly, drill it, and seal the holes.
Then doublers were added to glue the bulkheads back together. Not what you'd want to show anybody.

Following all this butchery it appeared the trunk was not pointing at the prow. I had glued the prow and stern together without clamping the deck in first to line it all up. I got lucky with the stern but redoing the prow would fix Emma's bent nose.
Cutting the prow apart and gluing it again got it into alignment.
Last edited by g'n's; Jan 23, 2018 at 01:09 PM.
Jan 19, 2018, 09:50 PM
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setting bulkheads easily


I've been struggling with elaborate arrangements to hold these bulkheads #1 and #4 steady while the glue sets. Grrrr
Well, today a simple way finally came to me. To prevent the bulkhead from sliding upward, blocks were clamped to the gunwales above the deck line. Then, to prevent it from sliding sideways, 1/8-inch strips of wood were glued to the hull sides against the bulkhead position. These strips were the secret to success.
With this preparation the bulkhead was glued with 5-minute epoxy without any trouble. The string was then used to tighten the joints 'til the glue set.

(note: I've also posted this message in my "Bearospace Schooner Irene" thread)
Last edited by g'n's; Jan 23, 2018 at 12:55 PM.
Jan 22, 2018, 03:46 PM
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Building Emma


Was thinking of ways to build Emma lighter. My modeling experience comes from about 30 years of building and flying RC Aircraft where weight savings are critical. Door skins although very cheap are on the heavy side. Was thinking of using poplar lite ply which is considerably lighter than door skins. The lite ply covered with 1/2 oz fiberglass cloth would make a strong and light hull. Has anyone tried this?
Jan 22, 2018, 04:19 PM
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robcrusoe's Avatar
I think you should ask Gary about this since he has factored in some important design specifications that include overall weight, keel/bulb weight. Your idea may well reduce the hull weight but for optimum handling, may increase the fin assembly weight.
I'm currently building a modified Emma (my first is fine, but I want to leave it that way) to make it faster in lighter conditions. From what he has told me there are pros and cons in increasing overall boat weight. On the lighter side it will move along somewhat faster, but not greatly so, but when the breeze eases off, it will slow down faster also. The heavier boat will not accelerate as fast but l the added inertia will keep the boat moving so it picks up a (presumed) return of breeze easier.
Like say, ask the guy who knows the the technical side of this amazing boat.

There is a full article on the making of a scaled down version of an Irene that worked out well, he used a very light hull material. Back towards the start of that thread
Jan 22, 2018, 11:13 PM
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Moved to Irene thread. Oops
Last edited by CarlMalone; Jan 22, 2018 at 11:25 PM.
Jan 23, 2018, 11:19 AM
sailtails - YouTube
Gary Webb's Avatar

Light ply ???


Quote:
Originally Posted by stephensackro
Was thinking of ways to build Emma lighter. My modeling experience comes from about 30 years of building and flying RC Aircraft where weight savings are critical. Door skins although very cheap are on the heavy side. Was thinking of using poplar lite ply which is considerably lighter than door skins. The lite ply covered with 1/2 oz fiberglass cloth would make a strong and light hull. Has anyone tried this?
Hi Stephen, I'll offer a comment, like a politician, without a real answer. Unlike aircraft, weight in a boat is not always a bad thing. Boats are designed to float "on her lines" and so the desired weight is determined by design. Of course, at the design stage, this is a compromise to suit "average" conditions.
I think the light ply with FG would be fine, and very nice to work with. The primary purpose in choosing door skin was its' low cost. I doubt there will be much difference in the end, but if the boat comes out a bit light, try her out, or enjoy the option of being able to add details or gear without overloading her.
Emma is not terribly sensitive, but I think performs best overall at 13.5 pounds (6.14 kg) as per plans.
Cheers Everybody - Gary
Jan 23, 2018, 02:12 PM
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Emma Lite Ply


Gary......... Thanks for your prompt reply. As you can guess, this is my first sailboat build so I need all the advice I can get. I think I'll build it with the door skins and try to hit the 13.5 lbs.
Jan 23, 2018, 11:15 PM
sailtails - YouTube
Gary Webb's Avatar

Fin & Bulb options for Emma


Hi Everybody,
I've tried out some variations on Emma's fin / bulb and would like to share what I have learned. Photos shows 3 fins,

The first (longest) is made as described on the plans, tried and proven.

The mid length fin is minus 3 inches (7.6 cm) and weighs 1/2 pound (.23 kg) less. I had hopes that being lighter and with less wetted surface, it would improve performance in light wind. I sailed 2 Emmas together, swapping fins, and was unable to observe any real difference in speed.

The third (shortest) fin is minus 6 inches (15.2 cm) and is 1 pound (.45 kg) heavier, bringing total boat weight to 14 - 1/2 pounds (6.6 kg). This was done to allow Emma to sail in a shallow pond, and was deemed a success. Handling and stability and speed seemed ok, but I suggest this version only if you must sail in a pond which cannot accommodate Emma's normal 20 inch (50.8 cm) draft.

Cheers, Gary
Jan 25, 2018, 12:22 AM
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robcrusoe's Avatar

Maxine (Emma mod ) coming togethere nicely


I agree that if it ain't broke, don't fix it. (Anna is just bouncy healthy)

If it sails just great, why make another one? And if I did, why, and how?

I'm doing it since my Anna and Crossbones' Nell were built to the same specs, so they could be properly matched raced, but you'll know that from earlier posts. Putting the hull together was pretty much to the plans, except for some subtle bulkhead surgery and a new adhesive.

But my first main mod was to install a drum winch system as per the Irene.
Most of my sailboats have drum winches but only a few with the continuous loop layout. Continuous is probably not correct, but it will do.
While the Emma arm winch works just fine as per the plans, and so it should since Gary doesn't use the first ideas that come to his mind, it is evident, my idea was to let the traveler go and set up the sheets also as per Irene. But, with almost a full 90 degrees of boom travel. Gary will tell you that neither boat needs all that additional capability, and from sailing mine I must agree, but the Emma is not quite the same smooth sailer that the Irene is and in lighter airs it just ambles along.
All l want to do is to be able to gauge how an Emma with more sail area will perform in comparison to the standard Emmas we have. Gary has responded to my request for help, initially, and so this version will have a 4" bow sprit, making a rather large jib possible and since the main boom and the mast have plenty of length, a larger main. He also suggests that since weather helming is a likely side effect, and extra inch or so to the length of the rudder should help to counter this somewhat.
The keel/bulb section will be interchangeable with Anna's so I'm looking at taking the combined weight of those up to the upper limit he talks about. The bulb will be removable, easier than the removable on Anna, so I can try different loads with the bulb weight.
Next job will be making the deck structures followed be setting up the standing rigging
.
I haven't determined the sail measurements yet, no point until the rest is in place, but then I'll make a set out of kite quality light rip-stop sails, on my trusty Husqvana.
Amazing the range of stirs you get when your sailing mates hear you are sewing up sails (Oh, can you knock me a up a new suit, mate??)


More later..
Last edited by robcrusoe; Jan 26, 2018 at 03:52 PM.
Jan 30, 2018, 11:58 AM
Registered User

Emma build


Could someone educate me on the pro's and con's of using a sail arm setup vs using a winch setup. Are there more than one type of winch setup (different types of servo pulleys) ? The Emma is my first RC sail boat build and any help would be appreciated.
Jan 30, 2018, 02:38 PM
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robcrusoe's Avatar

Drum Vs. Arm winch in the Emma


Yes, I can help as I'm well into building a modified Emma that has a Irene type drum winch instead of the arm version. My original Emma (all of 2 months old) has the arm winch. She is built the same as my mate's as both are to match race, so essentially must be near identical.

There is only one reason for my using a drum winch in this excellent designed and well tested boat and that is to give total availability of sheet travel, that is, anywhere between full in and full out. As it is, the arm winch, even if you move the hole on the arm out as far as you can ( mine is like that) the actual travel is something like 60%.
But I hasten to add that as far as I have been able to determine, this is more than adequate for the general sailing of this model.

So why bother? Well, my so-called Maxi Emma is simply being built to handle lighter conditions better, chiefly with oversized sails. However my long association with drum winches in a wide range of rc sailboats, from Rc Laser down to virtual toy boats, leads to being able to see how effective full range of sheet travel settings may be.

Both winch servos are by the same manufacturer and have the same ratings.

In my other sailboats that use an arm winch it is set up to give more travel by effectively doubling the amount of sheet travel, but at the expense of halving the torque (pulling power). In the Emma this is not used, but could be, but the reduction of power would not be acceptable , I believe.

To be frank, I'm not expecting any great performance improvement, but since I stock both winches it is easy to fit one and find out. The Emma has more than enough internal length to provide the necessary distance between drum and idler pulleys.

As soon as I have the Maxine (racy name??) winch functional I'll post a short video of what I'm talking about.

Would I recommend the drum over the arm winch? No. but would it matter? Again, no. The arm winch is easier to install.

Hope this helps.
Last edited by robcrusoe; Jan 30, 2018 at 02:50 PM.
Jan 30, 2018, 11:48 PM
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SA/RCFlyer's Avatar
robcrusoe have you tried modifying the servo by adding resistors to increase your throw? We use standard RC servos in our RG65s and get up to 180 degrees throw.
Jan 31, 2018, 02:22 AM
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robcrusoe's Avatar
Quote:
Originally Posted by SA/RCFlyer
robcrusoe have you tried modifying the servo by adding resistors to increase your throw? We use standard RC servos in our RG65s and get up to 180 degrees throw.
No, I've heard of it but never needed to look into it. When you say "Standard" RC servos, are you talking about those in the 9 KG range? I would have grave doubts as to using something that small in a boat of this size. The one Gary recommends, which is comparable to the ones I use, are 13.5KG at 6 volts. Both have 370 size motor, well mine do, anyway..
There is a bit of difference in power requirements between a 650 mm boat and an Emma and after today's run against RG65 (type) boats, and DF95's I'm inclined to think that Gary's design is, as he says, ideal.

Conditions were 30 to 50 kph. but mostly mid 30's with those higher gusts to make things interesting.

Have a look at the video. and bear in mind I was videoing as I sailed.

Bearospace EMMA sloop goes head to head with DF95 and DF65 (5 min 41 sec)
Jan 31, 2018, 05:30 AM
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SA/RCFlyer's Avatar
We use 12kg metal gear servos. Just used the 65 as an example to show it can be done. Here in South Africa imports are very expensive so we make a plan to get things working.


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