My second 750 build...with canting keel

Joined: 6:58 AM - May 27, 2014

11:09 AM - Jan 07, 2015 #1

Hi
After see the yachts in the Sydney Hobart race with the canting keel,, just had to have one.. so here my second build. With much googling I have come up with a design for my keel and control.
I went with the cnc cut foam and glass construction for speed of build.
I will put up many photos of what I am doing not so much text, so if you have any questions or queries just ask please.


Russell
7 layed up.jpg
7 layed up
6 glass cut.jpg
6 glass cut
5 joined and mounted.jpg
5 joined and mounted
4 stern done.jpg
4 stern done
3 bow done.jpg
3 bow done
2 ruffing cut.jpg
2 ruffing cut
1 the blank.jpg
1 the blank
7 layed up.jpg
7 layed up
6 glass cut.jpg
6 glass cut
5 joined and mounted.jpg
5 joined and mounted
4 stern done.jpg
4 stern done
3 bow done.jpg
3 bow done
2 ruffing cut.jpg
2 ruffing cut
1 the blank.jpg
1 the blank
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Joined: 9:00 AM - Apr 20, 2014

7:39 PM - Jan 12, 2015 #2

Yeah I've some questions, firstly awesome technique, looks perfect and way less manual labour than balsa and planking.
But, how do you release the polystyrene once the resin as gone off?
And, how then do you create the internal structure for fittings, servos, rudder, deck etc.

Be great to see more photos!

Cheers.
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Joined: 6:58 AM - May 27, 2014

8:40 PM - Jan 13, 2015 #3

Hi to all those watching......
From the mast frame forward stays the same using 5mm balsa wood frames glued in.
The render shows the proposed lay out for the rest.
The foam has a release agent on it (the pink colouring)
Have made the moving keel box out of clear plastic, this should be interesting the first time it put in the water. More on this once I've made the keel mount, keel and keel bulb.

Russell
boat rendor.jpg
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Joined: 6:58 AM - May 27, 2014

7:23 PM - Jan 20, 2015 #4

Thing have moved along a bit more with the following....

Hull has been removed from foam and had the frames and gunnels (gunwales) attached. bulkhead setup and shell.jpg frames and gunnel installed.jpg To operate the keel I needed some small pulleys,, could not find what I needed online, so made some up, here is the first test one ...very pleased with the result. pulley size.jpg pulley test.jpg Also here is the clear keel box and keel mount. canter keel mouting box.jpg This is to be assembled then put into the hull as one piece. It has 2 oring seals and 2 ball bearings that mount in to the clear plastic mount. The keel fin will be detachable from the keel mount canter keel mount 1.jpg Next is to mount up the 3 servos, the 2 keels, rudder and pulleys
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Joined: 6:58 AM - May 27, 2014

2:51 AM - Jan 25, 2015 #5

The keel box has been joined and hole cut in hull. A good join here will be important or it could be :oops:
Plus I have finished off a dozen pulleys keel box hull hole pulleys.jpg Here is the servo, keel box and pulleys mounted. keel servo and pulleys installed.jpg This is the angle the keel will move too. I thinking of using the rudder stick on the transmitter so that the sail trim and keel are under one thumb..Just hope I do not need three thumbs :lol: 087.jpg The lead bulb need to be around 650 grs but this might need to change so I was thinking of casting a round billet of lead and turning it to shape..... any suggestion here?

R
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racingSparrow
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10:34 AM - Jan 25, 2015 #6

amazing build.. im keen to see how this boat turns out.. great work.. those little pullies are great, how exactly do you make those? cheers, Bryn.
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Joined: 6:58 AM - May 27, 2014

9:04 PM - Jan 25, 2015 #7

Bryn thanks for your kind words and yes I find it an interesting build also,
The pulleys are CNC cut on my small machine i have.
These one are made from some 1.2mm anodized aluminum sheet and 1.2mm brass sheet I had.
The photo shows the inside of the sheaths and you can see the boss around the shaft mount to give the pulley clearance. At the top near the mount hole you can see 2 small holes these are to give a larger gluing area for the epoxy to adhere to, it like having 2 small pins. pully inside.jpg I used a 1mm cutter to make these and only take a few minutes to cut 10 sheaths (can see this in back ground of earlier photo) but long while to setup... :roll:
The pulley is cut from the 1.2mm sheet then I mount them in the lath and trim to size and with a small tool put the u shape into the pulley
The pulley axle is made from 1mm brass wire
After all this is the deburring and clean up, at this point is where I lose some parts as when dropped they disappear for ever... :oops:
The sheaths are then glued together and left to set,, next the pulleys are installed and one side of the axle is glue then the other and if you are good or lucky you have not glued the pulley to the sheath... :(
I am thinking of putting a pin point of oil on to the axle not so much for lubrication as the run freely but as to stop any corrosion in the future....just a thought.

Russell
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Joined: 6:58 AM - May 27, 2014

2:39 AM - Feb 08, 2015 #8

Well a few things have changed....
The idea of using the servo as a winch and line through pulleys for canting the keel died as tiring to keep tension on the lines was all too hard to maintain.
So ripped out the pulleys,rearrange servos and their mounts and made up some gears, really one 1/4 gear and one half gear, and direct drive the keel through these gears. This has a 2;1 gear reduction with the servo travelling 180 degrees. gears for keel.jpg I had to have two goes at mounting the servo as you can not have it mounted on the rubber mount and drive a gear train :oops: . as the gears jumped teeth :cry: gears mounted 1.jpg So to remount it while the plywood frame was glued in, I had to use some aluminum for the new mounts in the frame. now that I have used 3mm bolts and have a fixed threaded plate in place I can remove the keel servo much easier than with the wood screws. gear mounting 2.jpg If you holding the boat level and cantering the keel the amount of force need to hold the boat level is amazing. keel cantering.jpg inside gear cantering insided.jpg The deck is now glued on. deck glueing.jpg Made up some deck pulleys for the sail winch. deck pully.jpg Hope to get the hull spray putted and painted this coming week.
Still trying to work out a good hatch system... :?

Bryn ,,,,,I'm getting a feel for what it took you to make the very first sparrow boat....

Russell
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racingSparrow
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8:43 AM - Feb 12, 2015 #9

amazing looking build, realy cool gearing you've made. you've got to believe in your work for sure! It will sail, just depends how well really. Can't wait to the boat sailing, you gonna shoot some video?
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Joined: 6:58 AM - May 27, 2014

6:58 AM - Feb 16, 2015 #10

Are we there yet.........Well almost,,,it all finished just got to get it wet next.(hopefully tomorrow.)

Here a photo of the inside with a guard to stop anything getting catching in the gears...must keep up to OHS standard :lol: . inside guard.jpg The finished beast. finished.jpg Some things I add on this build was a switch on the deck so I do not have to remove the hatch cover for on/off.It is the brass tube behind the boomvang, push down for on.
Swiveling boom and vang mount, got some brass fitting off a mate that fitted perfectly on the mast section.
Made some adjustable fitting for the vang, back stay, and shrouds.

Russell
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racingSparrow
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7:49 AM - Feb 17, 2015 #11

really keen to hear how she sails! Bryn.
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Joined: 6:58 AM - May 27, 2014

2:13 AM - Feb 19, 2015 #12

Yes it does sail........
After a false start with a leak in the housing for the keel and the hull caused by me changing direction mid install. No damage done just time taken to fix it up with two drops of epoxy....Now no leaks at all :D
Here is a video of the keel being tested first time in the water,,,,it took some coordination to control the 3 stick on the TX and operate the camera thus the short video..

It is a different beast to sail with only half the lead in the keel the acceleration is noticeably quicker.
You sail it in the light breeze with no keel added as the wind pick up you add some keel and she stands up straight and pick up more speed, I can see this from the wake size increase.
One thing I was not expecting was when going to windward and add keel which swing out to windward that the boat turns down wind a little not to windward with the extra drag on the side,,This is only slight and a very small rudder adjustment is need
One must try not to over correct the heeling especially violently or in a tack and forget the keel then slam it over because you seem to lose all power and slow down, but practice will make this better.
One thing make it more of a challenge to sail is in mid strength winds where the keel may be mid way out, is the boat heeling due to the wind or you moving the keel??
Down wind you can tip the boat over a little to make the jib swing out to catch the breeze,,
You can give the sail a flick by rocking the boat to make them to set on the correct side and heel the boat downwind in light winds.

But overall it is a joy to sail and the build was of great interest
There many more tricks to learn with this boat and I will have much fun and time learning them.

More to come when I have had many more sailing hours

Russell
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Joined: 8:54 AM - Sep 06, 2012

12:27 PM - Feb 19, 2015 #13

Hi Russel,
Brilliant, nice engineering resources you have there. I have the skill but just the kitchen table to work with!
Just read your last post and watched the video, very impressed. You mention keeping everything under control with just two hands and a thought came to me, could you use a Gyro, as found in RC Helis, as an assist. Just an idea, maybe not a good one, I have not thought it through really.

Cheers, Terry
I was born intelligent, but my education made me stupid.
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Joined: 6:58 AM - May 27, 2014

10:20 PM - Feb 19, 2015 #14

Hi Terry
We were discussing that option just yesterday (great minds think alike) a gyro is generally made for course direction control and we want vertical control, will it do this I do not know but they're cheap enough to find out.
The next choice is a accelerometer and some software bit more involved. I will google and see if anything is ready off the shelf.

Russell
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racingSparrow
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7:18 AM - Feb 20, 2015 #15

what I don't get is how you stop any water getting in around the canting keel axles? how did you seal all those moving parts? very cool model, one of the best racing sparrows yet! Bryn
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Joined: 6:58 AM - May 27, 2014

8:35 AM - Feb 20, 2015 #16

Hi Bryn
I used some orings,,,If you look at the early photo of the keel axle assembly (it's on a wooden back ground) you can see the oring inside the bearings.These fit into the housing.
If you want more details let me know and I can send a CAD of it.

Russell
The owner of the only canting keel sparrow ;) :lol:
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Joined: 8:54 AM - Sep 06, 2012

9:49 AM - Feb 20, 2015 #17

Hi Russell,
As far as I know a gyro will control any axis, just depends how you mount it.

Cheers, Terry.
I was born intelligent, but my education made me stupid.
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Joined: 6:58 AM - May 27, 2014

11:09 PM - Feb 20, 2015 #18

Terry
I have the guys on the rcgroups forum having a look into using a gyro,,,There have had many good ideas and with their technical skills in this area we might be able to make it work...a work in progress.
http://www.rcgroups.com/forums/showthre ... st30846640
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