I have been following the discussion of the Equilibrium Rig with great interest. I think that it is possibly the greatest step forward in rig design for small models that we have so far seen.
More to the point, it has enthused me to put together a couple of different versions and stick them on the only viable Footy I have currently, a 20 year old Stollery Choppa. This is a long way from the styles currently being eveloped being both heavy and short in the fin. But it was designed as a indestructible children’s toy, not a contender for the Intergalactic postal record. It also has a difficulty for the wire based Equi rig. The extreme sheer forward means that the length of wire that can be bound onto the boom is limited before it has to take a sharp kink to clear the high bow. For this reason, and because the wire I had by me was rather thinner than others seem to have used, the whole thing is almost certainly too floppy.
An alternative was made in wood, using liteply and a joining web in 0.8 mm birch ply. The after (boom) section has the grain running horiozntal and is essentially stiff, as is the carbon tube boom is in the wire version. The forward section is grain vertical and is pretty floppy. If it proves to be too floppy, it can be stiffened up on the pond side by supergluing strips of 0.8 ply to it.
I intend to give these a try tomorrow. More results and pictures in my next.
A further effect of the Equi rig. I have started to put together one of the two Pipsqueak hulls I had from Brett some years ago when he was first getting the Footy off the drawing board and onto the water.
Thank you History man,that is quite a compliment coming from you( I am pretty sure I know who you are!)
It was blowing hard here today…about 25knots with gusts over 30.
We rigged a 305mm high “B” rig and let her rip.
Upwind the boat is totaly controllable and sailing like on rails,totally hands off.
downwind she was flying but nosing in from time to time…I think this can be solved with some alterations to the bulb.more on that later.
We also witnessed the first signs of a Footy surfing down waves…we have never seen this before.
This rig design has made all this possible,6 months ago I may not have even launched the boat today,But with what we have now we are scrapping over the transmitter and sailing these boats is now fast and fun.
I thought I was done for the weekend but these McCormack rigs are so quick to build, I have another ready to test. First one used too thin wire. It worked but flopped too far in even moderate gusts. I scrounged up some thicker wire and found an adapter to get my carbon tube onto the wire (chopped up an old fishing rod tip). It’s supposed to be very windy tomorrow, should be a good test.
I’ve been thinking about some of the adjustable versions being built. These things are so quick and easy to make, I’d just have a bunch in different stiffnesses and tunings rather than trying to make one adjustable. My $0.02
Thats it, im done, all sorted, next challange please. :heart: Todays sailing was a total success I am pleased to report.
The rig worked a treat and the boat promises some fast times.
My mate Terry posted a 7.04 which can be improved upon I know.
I built a new sail this morning.
It has a broad seam insert fitted for no other reason than it looks cool and I can do it.
With the stiffer wire rig and sailing in 2m/sec breeze it all worked great.
The sail shape is wonderful, do you think the broadseam helps much?
Here’s a video from today, showing it’s ability to track upwind without any rudder input. Downwind is another matter, as you will see, but this was hampered by trying to aim the camera at the same time. http://www.livevideo.com/video/E65B8C3ABF0047AA8C5DE6AF3F6364A7/rc-footy-sailboat.aspx
High wind testing went very well today. It handled gusts to 20 mph and tracked without any rudder input. Still had some submarining during strong gusts but these were not the typical winds we get around here. The skipper was getting knocked off balance a few times too.
Ian,
The sail shape is wonderful, do you think the broadseam helps much?
Tallastro, yours looks great too. I agree with your earlier comment about how easy these rigs are to make.
Here’s a video from today, showing it’s ability to track upwind without any rudder input. Downwind is another matter, as you will see, but this was hampered by trying to aim the camera at the same time. http://www.youtube.com/watch?v=CILRl2BB1bU
Brett the wire diameter is 2.5mm. It comes from the top section of a car radio antenna. Just don`t park around here right! (joke OK) :paw:
I am one of those sad blokes that picks up stuff that I find in the street or keeps the plastic utensils from the aeroplane meal coz “it just may be useful yeah.”:heks:
Bill the broadseam does make a little difference to the sail shape as the draft is already in the sail without too much foot round. :disguise:
Your video has inspired me to join “you tube” so that I can post my first attempt filmed with my still camera so not sure of the quality.
I know what you mean about aiming and sailing at the same time.
Us blokes can`t do this multitasking so well.
Here is my first video attempt so please be gentle with me as I am no Peter Jackson.
You may notice that I stalled the boat on a couple of occasions, I put this down to the sail I had made being extra long on the foot and so the centre of effort is too far aft.
That has now been altered with the removal of 10mm from the rear edge of this sail.
Hello Bill K… I am looking forward to seeing your rig in action at Wood Lake in a couple of weeks… please expect me to be all over it On the video, that gentle luffing on the long beat and the straight tracking is most impressive.
As mentioned above I made a couple of versions for my radio Choppa. Not the most suitable hull for the experiment, but what I had available. The trial took place on a pond with heavy tree shadow, swirling gusts and almost nowhere where there was a true enough wind to get the boat moving long enough in one direction to be sure of what I was seeing. I had some problems with rig balance, as the sails were very much quick and dirty approximations. I also was reminded that the Choppa’s origins mean that the rudder is really small and it’s very close to the fin, so you don’t get a lot of turning moment. So, not te best experimental set up. Nevertheless, some lessons were learned
Conclusions
1 The wire rig was way too floppy and probably any version that negotiates the Choppa bow sheer will be, even if the wire is heavier.
2 The wooden rig, as desgned was also too floppy, but improved when the fore end was stiffened with 0.8 mm ply. It still needs to be stiffer. The stiffener was put on in two sections to avoid glueing over the hole to which the sheet was attached. this produced a very interesting phenomenon as the twist was concentrated in the gap between the two pieces of stiffening. Holding the boat on the bank in an attempt to photo the twist increased the loadings and the spar failed in way of the unstiffened section, which also had a hole through it. Elementary engineering lesson; do not concentrate stresses on the weakest part of the structure.
3 The degree of flop needs to be tailored to the hull. The Choppa, because of its sheer weight (672 g on the water) is not an easy boat to heel in the winds I had on Sunday. Almost all the ‘give’ occured in the rig.
4 The Choppa needs a bigger rudder. Now I remenber why I only sailed my original radio version a couple of times after I had built it.
All these things will be taken care of before the next outing with bigger sails mounted on a stiffer wooden rig, or probably two or three to choose from. St this stage it’s very difficult to get a feel of what will work without any real experience on the water.
I thought I had attached some .jpg files to my preceding post, but they haven’t appeared. Can someone please advise how to do it properly. I’m new to this forum game.
Hi Russell, Ian Hull-Brown here from NZL.
We sailed against each other in Queensland @ Australian RM champs in 1986/7 if you are Russell Potts.
To post photo`s on this site look below the reply typing area for the “manage attachments” button, click on that and you will have the option of uploading a file from your computer or from a URL.
Make sure your photos are resized to less than 97.7 KB before selecting them with the browse button and then the upload command.
Do them one at a time with a maximum of four in any one posting.
We look forward to seeing your contribution.
Welcome to the madness of the FOOTY experience.
Cheers, IAN.
HM, it appears that the learning curve is pretty steep already. I look forward to seeing your pix.
My latest trial was to move the pivot point on the Z wire aft by 1", (which necessitated moving the stepping tube & sheeting block aft as well). The reason for doing this is to shift the pivot axis to be closer to the CE of the sail. The original placement is 4" (33%) from the nose. It was moved to 5" back(~42%). The goal is to make the helm more neutral when running downwind. In a strong wind, the boat gets a bit squirrely & can be hard to jibe. This is where a transom mounted rudder would exert more turning power The offset distance between the pivot axis & the sail’s CE is reduced from 2" to 1" , thereby reducing turning moment by 50%. BTW, I foolishly try to sail the rig without moving the pivot tube & it sailed like crap, would barely come about.
new Z wire, original wire & patterns on bench
new deck arrangement
profile view, close hauled trim. Hopefully the boat will continue to track upwind as good as it did before. No reason it shouldn’t, as the CE & CLR remain the same, as is the basic sailplan
4)aft view, running trim. The crossed marks on the sail is the approximate sail CE. The pivot axis extends up about 1 " in front of this.
Ha, Bill I have done exactly the same.
My original mast position was at 100mm from the nose but the pivot point was moved back to use the forrard of the tubes that Nigel had built into the fin case.
The forward measurement of the Z bend was then extended to match.
As I have said elsewhere each boat will have it`s rig altered and adjusted specifically for that hull set up.
We are getting there mate, just have to catch up with that bloke down in Dunedin and his equally fast son.:devil3:
thanks for the steer. I had been trying to put too much up in one go, which is probably why they were rejected. When I get the image sizes down a bit more, I’ll have another go.
And yes, it’s me. Can it really be 20 years? And we’re both still at it. My only consolation is that all the old men I seek out in my historical research seem to all their buttons on , largely because they have a consuming interest. I take this as confirmation of my intention to continue with my obsession while I have breath.
Another little problem for us two fingered typists. Any way to spell check postings before they go? I know how to spell, but my fat finger technique makes me look like an idiot unless I go over it with a tooth comb. I notice that many contributors are hapy to let their fat finger errors go, but I’m picky about these things.
On the video, that gentle luffing on the long beat and the straight tracking is most impressive.
Bill I have done exactly the same.