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Old Jan 27, 2012, 01:16 PM
0.9g retracts
Yellow Baron's Avatar
3" from insanity, 2' from the computer ,Richford, Tioga county, Southern Tier, New York, U.S., North American Continent, Northern hemisphere, Earth, The Sol System, Milkyway Galaxy, The Universe, The Current Dimension, Your Selected Realm of Reality.
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Build Log
Footy: Comet Gypsy Jr. "Shamrock VI"

I started this hull earlier in the week, it is built from the plans for a Comet mfg. Gypsy sloop Jr, but is planked instead of sheeted and enlarged by 10%. The original kit was made as a 11" free-sailed model in the 40's and had a full keel with no bulb and fin arrangement.

I will be trying to get away with a bulb on the full keel to get some more righting force, but as this is a small sleek boat there is not much room for more weight. The original sails were very open weave and I will be keeping to that; this is NOT a modern racing vessel, and will not be raced formally.

As you see it in the pictures the boat weighs 1.884oz. or 53.48g

I am going to shave and sand the mast so that it tapers from 3/16" at the bottom to 1/8" at the tip. Also I am thinking of remaking the keel out of all wood (remove the steel sheet) so that I can put that weight in the keel bulb instead of the keel, any suggestions (I will not make a deep keel)? I am trying to keep the lines and materials of the boat period accurate.
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Old Jan 27, 2012, 01:58 PM
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**neons**'s Avatar
USA, MA, Swansea
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Fred
Subscribed. Coming along nicely. I see the weight is in the sheet metal form . I think it will be fine but less righting abilities. Personally though in my chain of thought, it would be more effective as a bulb built along the bottom. The flat sheet will not have the same effect as an equal amount of weight at the lowest point in the hull. I still believe lead flashing in layers hammered flat then glued, and filed to shape along the bottom most edge to meet the 1 inch height will do what you need. It could be filed with a slight bulbouse shape in the width of the lead ballast to match the wood thickneses. With lead being heavier than the metal it may not be necessary to make it bulbouse. The keel will still be like the plan is size and shape. It will be hard to judge the amount of weight until built. I weighed the metal for the keel. It is 1.1 ounces (31grams).. The hull is not a displacement design so you have to be careful not to have to much keel weight. I do not like metal because of rust..

Can you add the first pictures to the above posting? I think it would be nice for your build log. Just a thought.
**Neons** Bob
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Last edited by **neons**; Jan 27, 2012 at 05:06 PM. Reason: Weight of the metal keel added
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Old Jan 27, 2012, 05:19 PM
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Here is a new thought. I do not know what Footy rules are. If you are using 2 servos for the rudder and the sheets you will have to figure in all the weight of the the complete electronics in the boat. It is like adding inside ballast and it will drop the waterline some. The higher up in the hull the weight climbs in the the less righting ability it will have. This will effect it in such a way that you will have to consider the keel weight adjustments. I think I would consider making the keel weight removable to add or shave it down if necessary. Maybe consider a SS screw from under and through the keel into the hard wood or blind nut. Another consideration is how to prevent water entry and bagging of electronics. A lot of thought goes into a tight space..
**Neons** Bob
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Old Jan 29, 2012, 08:41 PM
0.9g retracts
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3" from insanity, 2' from the computer ,Richford, Tioga county, Southern Tier, New York, U.S., North American Continent, Northern hemisphere, Earth, The Sol System, Milkyway Galaxy, The Universe, The Current Dimension, Your Selected Realm of Reality.
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Bob, this will be my... 12th(I think?) Footy. The rules are 2 channels, they do not say what those are for. Normally it's one servo for the rudder(s) and one larger servo for the sails.

I have already been shopping around for the lightest radio gear I can possibly find. Receiver: 2.5g; rudder servo: 2.9g; sail servo: 15.5g; battery: 4g (130mah single cell lipo, will be plenty).

My mast is 18" off the deck with a 6" main boom. The genoa is under half that size. Total area is 61.875"sq. Now, having said that what kind of torque would a rig like this need? The servo I mentioned above has 44oz-in, how much less could I get away with?
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Old Jan 29, 2012, 09:28 PM
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Hi Fred,
I guess you are doing your home work and have some good experiences with your Footy class. I have very limited experiences in model sailboat sailing. I only have the 2 boats that sailed in the mid 70's. There is not much I can do to help you with the servos. I buy all my equipment from Hobby King. They have good selections and reviews on each piece model supplies below the product. They give all the measurements in mm. I use a metric ruler and an online conversion scale when I by there. I like the Hextronic servos. They do have many micros. I fly a lot and have experienced the Hex 500 and 900 servos. I use the 500's in many of my foamie aircraft.These are probably bigger than needed though. I did order some very small micros but it has not come in yet. Maybe something like these are needed Watch out for the plug compatability. Measure and read all the reviews.
http://www.hobbyking.com/hobbyking/s...vo_0_2D5g.html
**Neons** Bob
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Old Feb 05, 2012, 07:24 PM
0.9g retracts
Yellow Baron's Avatar
3" from insanity, 2' from the computer ,Richford, Tioga county, Southern Tier, New York, U.S., North American Continent, Northern hemisphere, Earth, The Sol System, Milkyway Galaxy, The Universe, The Current Dimension, Your Selected Realm of Reality.
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I finished the mast today, found some really small brass plated steel eyelets that I'll be using, pictures tomorrow.
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Old Feb 05, 2012, 07:54 PM
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Hi Fred,
Sounds great. Nice to see you are putting together a nice model that will sail and make a treat for the eyes bounding along at the pond . But when she is sitting at home on the dock it will still be a nice display also.
**Neons** Bob
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Old May 09, 2012, 09:04 AM
0.9g retracts
Yellow Baron's Avatar
3" from insanity, 2' from the computer ,Richford, Tioga county, Southern Tier, New York, U.S., North American Continent, Northern hemisphere, Earth, The Sol System, Milkyway Galaxy, The Universe, The Current Dimension, Your Selected Realm of Reality.
Joined Dec 2006
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A few days ago I received the parts I ordered from Hobbyking.com in April (some were on back order) I have gotten a few little things done on the boat so I will post pictures to get everything back up to speed. The sails are just paper mockups

Equipment....
Receiver: 2.0g
OrangeRx R415 with shrink wrap removed
Battery: 4.2g
Turningy Nano-tech 160mah single cell lipo
Rudder servo: 1.9g
HK-5320 Ultra-Micro Digital Servo
Sail servo: 15.7g
Corona DS-929mg digital servo 2kg.cm torque
Assorted wires (extensions, converters, ect): 1.85g

Total: 25.6g (.9oz)
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Last edited by Yellow Baron; May 09, 2012 at 09:38 AM.
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Old May 09, 2012, 10:21 AM
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Absolutly beatiful little model. just sooo "Classic". It has been some time since I last saw here being worked on. You are so close to the finish. I can't wait to see Gypsy finished. I am very interestedin this project. Someday when you sail the mini yacht, I would like to see how it all turns out on the pond. I hope it is a great success. I am not to knowledgable about Footy Class sailing. Maybe I will see an example first hand. Thank you Fred for the great pictures. Brings back great memories for me.
**Neons** Bob
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Old May 09, 2012, 03:42 PM
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Richmond Virginia
Joined Oct 2009
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I dont think the wieght matters as much as the deminesions of the craft in footy.. I could be wrong and If I am, someone please correct me. Im chasing the battery on my lap top here at the pub,
BUT, AFAIK, to be legal for race day, a Footy mearly needs to fit with in the footy box. as in a square foot qualifying box, the mast can hang out, but the boat itself must fit within said box.

it is a beautiful little boat! the club I talk to is all about running the RGZ-65 class in regattas and going against other clubs, And I think that is a failing amoungst various boating clubs. a focus is good, but boating is a limited facet of the hobby and we all need to be inclusive to bring more people in to the stuff that we do from one offs, fun scale, scale, live steam, electrics, and yes, even IC racing, which is becoming more and more a solitary pursuit for obvious reasons. but, bring everything to the pond and just have fun

my little 17" sloop down thread is also a RC version of free sail design. and it's also going to be a non competing model, just a fun boat to play with. borrowing ideas from footy and other size boats.
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Old May 09, 2012, 04:53 PM
0.9g retracts
Yellow Baron's Avatar
3" from insanity, 2' from the computer ,Richford, Tioga county, Southern Tier, New York, U.S., North American Continent, Northern hemisphere, Earth, The Sol System, Milkyway Galaxy, The Universe, The Current Dimension, Your Selected Realm of Reality.
Joined Dec 2006
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Bob,
I was busy building a micro plane for a contest, 17" Waco YMF-5. I also got caught up trying to figure out the planking over the chine of the hull, I'm still working on that. I also needed to get the radio gear installed before finishing the planking.

Which brings me to a question: besides replacing the pot, is there any way to modify a digital servo for multiple rotations?

bgnome,
You are correct in there being no restrictions on the gear in a Footy beyond no more than 2 channels and the battery goes in the hull. The hull I'm building being so small and having such little displacement, along with having such a short keel; keeping radio gear weight to a minimum so every gram could be put at the bottom of the keel was of utmost importance. Everything but the mast, boom, bowsprit, rudder (with some restrictions), and yards (if the boat has them) must fit in the box. The box is 12" long, 6" wide, and 12" deep, there are opening for the rudder and bowsprit to stick out of, but if you do not have a rudder than sticks out the back of the hull (it is under the hull for example) you can place the hull diagonally and have a hull nearly 15" long. The nearest club to me is about a 4 hour drive one way, so I am not a member of one. It does seem like most have one preferred class and tend not to notice others very much. Does your club have an open class day?
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Old May 09, 2012, 05:24 PM
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[QUOTE=Yellow Baron;21566973]Bob,
Bob
Which brings me to a question: besides replacing the pot, is there any way to modify a digital servo for multiple rotations?
QUOTE]

I do not know much about servos reworking. I will say that I found this nice lttle unit that will run 3 servos. and used on retracts. It adjust the up down speed and it will reverse 1 servo and maybe a few more functions. Read the reviews abd discussion. I like this gadget. You can run servos on the boat with it also. I think you would find use for it. I know it will be of good use.
http://www.hobbyking.com/hobbyking/s...idproduct=8863
I am building a 10 foot wing flying boat. 4 e-motors. Big project.
**Neons** Bob
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Old May 09, 2012, 07:56 PM
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bgnome's Avatar
Richmond Virginia
Joined Oct 2009
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I modify regular servos all the time for continous rotation. As one of my other hobbies is robotics, they make great gear drive motors. kinda like a poor mans stepper motor.of sorts. I unfortunatly have never modified a digital servo for such an operation though. but a quick read up on the interwebs tells me that the modification is pretty much the same for a digital as a standard analog, it was a "quick" read, but its not replacing the servo, its taking it out of the equation all together. leaving it wired, but removed from the casing. and zero'd in

when I modify a standard servo, I pull the gear box off, remove the stop from the top gear zero the servo with a servo tester or test transmiter, unplug it hot, glue the pot in that zero position and put everything back together.

modifying a Hiteck HS-55, for example is a little more difficult as the pot functions as the spindle for the top gear.and you cant trim off the pot tap and glue it.

you gotta pull the top gear, drill out the center so that the gear can rotate, but is still supported, and on the bottom end of the pot, you have to solder the center spindle of the pot to the case so it can't rotate once zero'd

it all depends on the servo really. but it's usually straight forward.

this video of this.. thing... ive been working on uses two HS-55's for the motors that were modified for CR, but.. they are Analog type, not digital, but like I said, the modification doesn't seem that far off from what I've just looked up.
Small RC Janson Strand Beast type walker, Prototyping (1 min 7 sec)
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Old May 09, 2012, 09:45 PM
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Great stuff . Nice to watch that ingenious operation. Way out of my league. Thanks.
**Neons**Bob
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Old May 09, 2012, 11:02 PM
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bgnome's Avatar
Richmond Virginia
Joined Oct 2009
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naw bob, I wouldnt say that things out of your league.. its a... whole lot of small parts mind you, a whole mess of 4/40 and 6/40 nylon lock nuts, all thread rod and bolts, its a lot of patience to put it all together mind you. then of course.. adjustments


Bob? I assure you that I'm not really that bright, I just like interesting things and the design for that thing is freeware, and I have full permission from the designer to give it away I cant claim credit for the design, but if you have access to a laser cutting service, I can get you the appropriate files and the some what vague assembly instructions if you want to give it a try. I currently I have mine set up so it uses a tank type RC control, or in the plane world, like a V-tail servo mix. full forward it goes forward, full back.. reverse, and left or right of course slows down or speeds up as directed. but because the drive system is based off of CR servos, no separate speed controls are necessary, unlike a tank type drive.

the top of the thing is laid out to mount an Arduino open source micro controller board, so yo can apply whatever type of automation you want to it.

in my above post, when I said the spindle of the HS-55 pot has to be soldered to the case, I of course meant the case of the pot, not the plastic outer casing of the servo itself. you are locking the servo position pot at zero. so when you are sending a signal from the tx to the rx the servo is trying to go to the position according to what the TX says, but since its never getting past zero? it keeps going, because there is no mechanical stop on the main gear? it keeps going. speed control is still there, stop position is not. Your servo is now a high torque gear drive.

now folks.. correct me if i'm wrong here... but most servo pots are 180 degree turn pots, dedicated servo winch pots are 360 degree turn pots, or more on the line of a stepper motor.

since never dealing with a digtal servo, I would assume that it's still using a analog positioning servo but there is a A/D converter on the servo board that's sending that feed back to the RX for.. well, whatever it does. instead of analog resistive feedback, its sending 1s and 0's. it can give you more percise control, obviously.
but otherwise. a servo circuit board really isnt anything more than a H-bridge when you get down to the dirty nasties of the circuit.


sorry if all this is like hijacking the thread.. carry on with yo bad selves
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