Tornado Catamaran

philiprawson.rcsaili · November 6, 2004, 11:02am

Hi people, new bloke here…

I’ve just gotten into the idea of sailing models and have recently completed my first OD… a scale(ish) Tornado catamaran.

I stumbled across this forum last night and was mightily impressed by the standard of expertise here, so if some of you more experienced designers and sailors would look over the details of my new boat I’d appreciate it.

I’m looking for general advice… where have I gone wrong? what could I improve? General hints and tips…

Details of the Tornado are on my website… www.flymodels.co.uk - navigate to “what’s on the building board”

Cheers,

Philip Rawson

www.flymodels.co.uk

Matthew_Lingley · November 6, 2004, 12:31pm

Niiice! I spent most of the summer sailing a Tornado sport, the boats rock. Have you tried sailing it without lead in the daggerboards?

Luff 'em & leave 'em.

philiprawson.rcsaili · November 6, 2004, 3:02pm

<blockquote id=“quote”>quote:<hr height=“1” noshade id=“quote”>Originally posted by Matthew Lingley

Niiice! I spent most of the summer sailing a Tornado sport, the boats rock. Have you tried sailing it without lead in the daggerboards?

Not yet… I’ve plans to make a range of daggerboards and sails for different conditions.

I’ve just discovered the concept of panelled sails… my next set (for slightly higher winds) will be an experiment in camber inducing panel joins…

Philip Rawson

www.flymodels.co.uk

Dick_Lemke · November 7, 2004, 10:11am

Hi Phillip -

just curious as to what winch you are using. I didn’t see it listed on your site, but did notice the comment about 2 turns to dump the main. Perhaps a HiTec 725 drum - or - maybe the small Futaba ???

dansherman · November 7, 2004, 11:26am

great work Phillip, i love the double planked hull. Thats something i think i might have to look into.

-Dan

philiprawson.rcsaili · November 7, 2004, 6:57pm

<blockquote id=“quote”>quote:<hr height=“1” noshade id=“quote”>Originally posted by Dick Lemke

Hi Phillip -

just curious as to what winch you are using. I didn’t see it listed on your site, but did notice the comment about 2 turns to dump the main. Perhaps a HiTec 725 drum - or - maybe the small Futaba ???

I’m using a Hitec HS785HB. It will do about 4 turns, but I’m only using about 2… the length of the jib boom is a limiting factor the way I’ve set the sheeting system up.

Philip Rawson

www.flymodels.co.uk

philiprawson.rcsaili · November 7, 2004, 7:03pm

<blockquote id=“quote”>quote:<hr height=“1” noshade id=“quote”>Originally posted by dansherman

great work Phillip, i love the double planked hull. Thats something i think i might have to look into.

-Dan
<hr height=“1” noshade id=“quote”></blockquote id=“quote”>

Apart from the notes on my website, the only thing s to add are… use plenty of glue for the outer layer of planks and flood the inside of the hull with a good sealant. On my Triple Crown, I’ve got the planks starting to show through the finish, despite brushing the inside of the hull with epoxy. My Tornado hulls had the sealer poured in and sloshed around before draining the excess out. It even found it’s way through the hull skins… The planks aren’t showing through the finish though…

Philip Rawson

www.flymodels.co.uk

lucashurt · November 16, 2004, 5:45pm

Beautiful Craftmanship on the Hulls. Inspiring for sure. Thanks for taking the time to share.

Would you say that the double planking is the key to getting a usable wood finish on your models.

Luke

philiprawson.rcsaili · November 16, 2004, 6:12pm

<blockquote id=“quote”>quote:<hr height=“1” noshade id=“quote”>Originally posted by lucashurt

Beautiful Craftmanship on the Hulls. Inspiring for sure. Thanks for taking the time to share.

Would you say that the double planking is the key to getting a usable wood finish on your models.

Luke
<hr height=“1” noshade id=“quote”></blockquote id=“quote”>

Thanks for the positive comments…

Designing ways to make a task easy is what I’m good at, boats I’m a beginner…

Reading up about planking hulls, I was put off by the need to get a single layer of planks laid neatly. The double planking method means that the first layer can be laid with a lot less care, the second layer, being much thinner is easier to do.

A side effect is the overall stiffness this gives the hull due to the wood grain running in more than one direction. Epoxy/glass finishes tend to shrink very slightly, with the result that, on thin, hollow structures it leads to distortion of the surface.

My double planked hulls have been a stable and solid surface to take the finishes I’ve used… although I admit that I haven’t made a single planked hull to make any comparisons.

Philip Rawson

www.flymodels.co.uk

lucashurt · November 18, 2004, 7:48am

Philip,

Thanks for the comment on your double plank idea. The reasoning is solid. Do you think the layer of glass is necessary if you leave the frames in the hull.

I noticed your cat has little bulbs on the keels. Do they weight enough for self righting status? Have you sailed the boat without ballast? What are your experiences with different ballast weights?

Luke

philiprawson.rcsaili · November 18, 2004, 4:42pm

<blockquote id=“quote”>quote:<hr height=“1” noshade id=“quote”>Originally posted by lucashurt

Philip,

Thanks for the comment on your double plank idea. The reasoning is solid. Do you think the layer of glass is necessary if you leave the frames in the hull.

I noticed your cat has little bulbs on the keels. Do they weight enough for self righting status? Have you sailed the boat without ballast? What are your experiences with different ballast weights?

Luke
<hr height=“1” noshade id=“quote”></blockquote id=“quote”>

Hi Luke,

I’ll tell you where my experiences with finishes came from… fast aerobatic gliders that can be stuffed with lead to make 'em go fast. They’ve also got be strong and durable 'cos they land on rough ground, quite often at a reasonable speed. For a glider, the better the quality of finish, the better the performance… glass like finishes and accuracy of form are good for performance.

Naturally, I took this approach when I started with the boats. The double skinned hulls are plenty stiff enough without the glass finish, even without the frames. I reckon that, over time, the frames would start to show through the hull with natural movement of the wooden skin. The glass does offer much greater durability for very little weight gain. I reckon with the glass and resin I used on my IOM Triple Crown I added about 1-2oz over a varnished finish of the same quality. I’m only using 1oz/m2 glass cloth… BTW, my Triple Crown came out 1lb underweight.

The bulbs on my Tornado each carry 1lb of lead. Before I fitted a stiffer and heavier mast, The boat, if left on it’s side on the ground would try and self right. In water it was a different matter though, as the sails stuck to the water.

I’ve not tried different keels yet… I’ve only had the boat out on 4 or 5 occasions… My first change will be non-weighted keels. Should be safe in 6-7mph winds. I’ll also make some with more weight eventally.

In the longer term, I’m looking at taking the lead off the keels and adding weight-shift. A couple of lbs of lead moving from one hull to the other should keep the boat flat in 10-15mph winds or so.

Then there’s the smaller set of sails… enough to keep me busy for the winter…

Then again… I want a planing monohull…

Too much to do!

Philip Rawson

www.flymodels.co.uk

dansherman · November 18, 2004, 8:32pm

Philip

I don?t know if you?re interested, but here are some links about multiple layers of planking.

The full size builders call it cold molding. Usually the first layer is parallel to the keel. The second layer is 45 degrees to the keel, and the third layer is 90 degrees to the second layer. Then it?s all glassed.

http://www.worldwideflood.com/ark/basic_hull_design2/cold_molded_hull.htm
http://www.dolvik.com/construction2.htm

S?ren Andresen has done something really similar with models, one layer of balsa, and then a thin layer of mahogany at 45 degrees to the balsa. You can see some photos here.
http://groups.msn.com/RCSailing/bouldingofawoodeniom.msnw
http://groups.msn.com/RCSailing/rc900nuberu.msnw

If I could find a supplier of quality 1/64? mahogany veneer, I think 3 layers of this with a light layer of glass over top, would make an extremely strong, and light hull, not to mention really beautiful.

-Dan

Beachbum · November 25, 2004, 4:02am

I Just love the looks of your Tornado. Some Functional parts had to be added to make it sailable, but your boat can easily be recognized as Tornado. And the best part is that it really sails, unlike many scalemodels. If you add a genaker pole and retractable genaker to make it look more like the modern newly rigged tornado, You can name your price, because i will buy one

And The tornado your father owns really should be upgraded with the new rigging. Old tornado is like an old English sportcar, elegance and finesse, but with the new rig its like a modern sportcar, elegance is still there, but when necessary you have also the brutal power in your use.

Also that “cross-planking” was very popular way to build real scale boats at the Veneer-gold-age ranging from optimists, FJ, FD to IOR half Tons. Diagonally placed planks add torsional stiffness and wood structures are like any strutures: put the fibres to face the loads.

I have also built Plane Wings with double planking: The first plank is from foam and the cross planking is single layer veneer glued with heat dispersing glue and Ironed to place with mildy heated cloth-iron. Fast and furious, as you can have the second layer attahecd in a big wing in like 20 minutes.

HJ

“Expertice is gained trough mistakes. However repeating
same mistake is not learning but stupidity.”

Matthew_Lingley · November 25, 2004, 5:07am

“And The tornado your father owns really should be upgraded with the new rigging. Old tornado is like an old English sportcar, elegance and finesse, but with the new rig its like a modern sportcar, elegance is still there, but when necessary you have also the brutal power in your use.”

I’ll second that, also adding that the Sport rig makes it into pretty much the fastest production boat you will come across, So its like owning the fastest production sportscar!

Luff 'em & leave 'em.

philiprawson.rcsaili · November 25, 2004, 6:03am

<blockquote id=“quote”>quote:<hr height=“1” noshade id=“quote”>Originally posted by Beachbum

I Just love the looks of your Tornado. Some Functional parts had to be added to make it sailable, but your boat can easily be recognized as Tornado. And the best part is that it really sails, unlike many scalemodels. If you add a genaker pole and retractable genaker to make it look more like the modern newly rigged tornado, You can name your price, because i will buy one
<hr height=“1” noshade id=“quote”></blockquote id=“quote”>

Yipeee… if I’m naming my own price you can have anything you want… full scale rigging, rotating mast… you can even have ceramic balls in the rear traveller! Actually, the reason my boat isn’t quite so scale is that I’m fundamentally lazy

As for the new rig…The later rig is quite distinctive with the squarer top… I think my next sail may be that shape now I’ve been reading up about how I can control the top of the sail.

I guess that you weren’t being entirely serious about paying me lots and lots of money, so you might be pleased to know that I’ll be publishing the lines on my website when I get round to it…

<blockquote id=“quote”>quote:<hr height=“1” noshade id=“quote”>
And The tornado your father owns really should be upgraded with the new rigging. Old tornado is like an old English sportcar, elegance and finesse, but with the new rig its like a modern sportcar, elegance is still there, but when necessary you have also the brutal power in your use.
<hr height=“1” noshade id=“quote”></blockquote id=“quote”>

Talking of ceramic balls… I’m sure my father and the co-owner of his boat would love to upgrade to the latest rig… but as they’re both turning 70 this year, I think the period rig is more in keeping with their agility. They’ve already said that this will be their last boat…

Philip Rawson

www.flymodels.co.uk

Beachbum · November 25, 2004, 6:44am

<blockquote id=“quote”>quote:<hr height=“1” noshade id=“quote”>
Yipeee… if I’m naming my own price you can have anything you want… full scale rigging, rotating mast… you can even have ceramic balls in the rear traveller! Actually, the reason my boat isn’t quite so scale is that I’m fundamentally lazy
<hr height=“1” noshade id=“quote”></blockquote id=“quote”>

Fundamental laziness usually leads to serial produceability, so thats not a bad thing Also Systems should follow Fuction, so I think that the only ceramic balls will still remain on the sailor

<blockquote id=“quote”>quote:<hr height=“1” noshade id=“quote”>
As for the new rig…The later rig is quite distinctive with the squarer top… I think my next sail may be that shape now I’ve been reading up about how I can control the top of the sail.
<hr height=“1” noshade id=“quote”></blockquote id=“quote”>

Just remember that if you get a larger main, you will have more weather helm. On the new T jib is also modified so that the leeach starts from the genaker pole and not from the wire crossing. The new jib is same area but it is taller and narrower. I dont see how that could be added to scale model without refirrign the whole rig idea.

<blockquote id=“quote”>quote:<hr height=“1” noshade id=“quote”>
I guess that you weren’t being entirely serious about paying me lots and lots of money, so you might be pleased to know that I’ll be publishing the lines on my website when I get round to it…
<hr height=“1” noshade id=“quote”></blockquote id=“quote”>

Yah [:D][:D] Seeing the lines would be excellent, BUT i am not totally wrong by saying that if the boat sails well, it could be kitted and made one design class. Multihulls do not have one design class yet and an affordable well sailing scale model boat might do the trick.

<blockquote id=“quote”>quote:<hr height=“1” noshade id=“quote”>
Talking of ceramic balls… I’m sure my father and the co-owner of his boat would love to upgrade to the latest rig… but as they’re both turning 70 this year, I think the period rig is more in keeping with their agility. They’ve already said that this will be their last boat…
<hr height=“1” noshade id=“quote”></blockquote id=“quote”>

Last summer I saw Paul Elvstr?m ( 75 or so ) sailing Tornado and My skippers father got the spin kit ( our old one with aluminium pole ) this year at the well done age of 63. Anyways, 70 and still sailing a tornado is very respectfully done!!

HJ

“Expertice is gained trough mistakes. However repeating
same mistake is not learning but stupidity.”