Entwurf: Apsara Bouchain

[abi]

Hello again.

After 4 months, various problems and mistakes I finally baptized Ocypète (Ωκυπέτη).
Unfortunately there was no air so we had to postpone yesterday's races and my tests. Here is a photo of her just before her first swim and a short video of yesterday's event, where only the "M" class boats managed to race.

http://www.youtube.com/watch?v=6iY4THwQ ... r_embedded

I'm currently putting together a build log with many photos so please be patient.

[VeitHAM]

cherete,

please keep us informed about your boat and the greek rc-sailing scene.
What are your experiences with the una-rigg or MC-rigg.

efcharisto poli,

Veit

[abi]

Hello Veit,

Sorry for the late answer,
So do you speak Greek or just get the basics?

After writing a loooooong post I found out that I was logged out and lost everything.
So I'll try to quickly write a shorter one.

In 2003, I discovered the existence of a group of 6-8 people with IOM boats and after some research, bought a RTR, Bagheera from meterboats in Sweden. We didn't do much racing though, so we eventually faded away.
In 2010, one of the friends, found the forum www.rc-boats.gr about nautical modelling in general (scale, static, speed boats, warships, sailboats etc.) with almost 1000 members all over Greece. The very next year we decided to begin racing (properly this time) our sailboats and by now we are in the middle of our second nationals for the classes IOM, Marblehead, RG65, Footy and Open with more than ten boats in each. By next season, due to the rapid increase in boats we'll have a new category for the Victoria class boats that now compete in Open.

Especially for the RG65, our president Vangelis Simonidis visited Argentina to meet with the founders of the class and introduce our group. We also created a new site www.rg65.gr There you may also find the complete build log (in Greek and English) with photos of my Apsara Bouchain. http://www.rg65.gr/index.php/build-log (it’s a very slow site so please be patient).
At the same time, there is a building frenzy with some people building 2-3 different boats. One bought a kit and some build molds to create carbon boats. There is even a Transat design, being built but will be racing out of competition due to it’s dual rudders.

About my boat and the sail, after two racing days, I may only say that it’s not yet competitive at all. As I’m no expert, I did many deviations and mistakes during the build. So now I’m not sure if it’s the hull or the sail (or both) that have the actual problem. A 1:1 sail maker who saw it, suggested I should raise a bit the sail on the mast and look carefully if the boom bends a lot with wind and messes up the sail’s shape.

This Sunday we are racing again and I have asked a friend, to lent me a swing-rigg to see if there is any improvement. Another idea is to build a triangular Una-rigg, a larger version of the one on my Footy Razor3, but it will be much sorter than the rest of the fleet.

That’s all for now,
I’ll be back next week with the results of my tests,

Ragards,
Abi

[VeitHAM]

Hello Abi,

You are right, I think my knowledge of your language is still less than basics. Sorry for that.

Thank you for your detailed report intruducing to us such a lively RC-sailing scene in Greece.
But, you have these wonderfull beaches with warm waters .
Your building blog reads rather professional; boat building always is full of experiences to be made, that's it because we like it so much.

Thank you and best wishes, please keep on reporting,

Veit

regarding my private relations with Greece, I send you a pn (private message)

[abi]

Hello again,

Thank you Veit for your kind words.

Yesterday we had the postponed last year's airless race day. We also had the programmed day for the Footy class. Three races for each class with the right to throw one out. My Footy Razor3 got a 1st, 2nd and 3rd place which means I was first and keep my place in the championship.
My RG65 was better this time, but still was far from being competitive. Two times second to last and a DNF due to a plastic bag that was caught up my rudder.
Our wonderful beaches are for swimming only, since we have some people swimming all year long and cannot race close to them. Also we try to avoid open sea areas due to the waves and the possibility, if something goes wrong, to look for our boat at one of the wonderful islands
Sailing for now, takes place in a port with not very clear air but worst of all, when South winds blow it fills with garbage. Not ideal to decide a race on who didn't get stuck to something.
We are seriously searching for alternative sites.
It seems that Ocypete is a fair boat after all and my problems come from the sail or just my difficulty to trim it correctly. The trick to move the sail upwards helped a lot to be able to trim it better and achieve higher speeds. It is very fast going downwind and doesn't dive.
I'm still having serious problems when it tacks, since it stalls for some seconds or refuses to complete the turn, under average air speeds. I don't think that I have such a problem but I'll ask anyway, how many degrees does your average rudder cover from extreme left to right?
It has a wide angle going upwind. I did tests moving the sail forwards then backwards but did not reach a satisfactory setting.

I'm seriously searching for alternative una-rig designs since this was a scale up from a Footy design. Such as the one for Graham Bantock's Wee Nip that has a much closer size (70cm)
https://sites.google.com/site/theweenip/

Also I'm thinking about building a new boat out of PVC foam and correcting my previews mistakes.

[abi]

The video from last Sunday's races
http://www.youtube.com/watch?v=Gmr-L3Kn ... r_embedded

[VeitHAM]

yassou Abi,

I will try an answer to your questions. Don't know whether they are quite correct.
The rudder should go ~25° to either side. It should be balanced right, that means the area in front of the axis should be 25% of the total area.
Balance is also a problem with the sailarea. The una-rigg should be devided like a swing-rigg; ~ 28% sailarea in front of the mast-pivot and ~72% behind.
Perhaps you should experiment with the position of the mast on the boat. Here again the centre of the total sailarea should be in front of the lateral area of the boat in the water. The value may be about 8% of lenghth of waterline - 50mm.

I add some links. If they are not helpfull, at least they are interesting for study

http://iomdesign.wordpress.com/rigs/

http://www.rcsailing.net/forum1/showthr ... quilibrium

http://www.rcsailing.net/forum1/showthr ... tion/page2

And this is the ultimate FOOTY design!

http://www.rcsailing.net/forum1/showthr ... ty-Catboat

Best wishes for the Greek sailors, Veit

[VeitHAM]

yassou Abi,

here is just an other tread about tacking problems and balance of the boat:

http://www.rcsailing.net/forum1/showthr ... t-Position

good luck, Veit

[abi]

Hi Veit,

Thank you very much for the links. They are very helpful.
The actual CE of my unarig was a subject of discussion with the friend who made it. We had discussed this calculation method about a year ago and I have forgotten it. Did not know though, that you could do the same with the boat.
The original unarig design was also, for a single panel, where we made it out of 4.

This Sunday we are racing our IOM and Open class boats. I will post the video when ready.

I’m still looking to borrow from a friend, a swing rig that would fit my 3,5mm tubes. This way I will be certain that the boat is ok.
Another thing to do is to create a new boom moving the point of rotation. Luckily enough it’s not glued to the mast so I will not have to create the entire thing from zero.

[abi]

Four months in limbo….and suddenly a medium earthquake shook Athens. Then some summer rains…it didn’t take much for my head to spin.
IT’S DREMEL TIME.
Poor Ocypete stood there patiently as I unleashed my fury upon her. Two starless nights later and this is how she ended up looking. There is even a whole just in front of the keel as I was trying to remove the previous winch stand and the drill went all the way through.
The stern was redesigned to be able to lower the rudder servo and keep its arm outside the boat.
I still haven’t decided about where the sail line will exit but there is much to do till then.
Now I have two things to workout: What kind of sail should I use and if the Hobbyking 6CH TX helps with the six rotations the winch takes, so I may gain speed in line movement.