does any one know if you can get new gears for a hitec sailwinchhs-725bb? just riped the drum off the last gear:(
Never hold your farts in.
They travel up your spine, into your brain,
and that’s where sh*+y ideas come from.
also does any one know of a way to mke a winch that is very strong and is fast and is about the same size as a hitec sail winch?
Never hold your farts in.
They travel up your spine, into your brain,
and that’s where sh*+y ideas come from.
have u checked the hitec webpage? or MODEL ENGINES Mr. MIKE FARNAN 44 DOWNING STREET,OAKLEIGH 61-3-9569-4440 61-3-9569-0930 mikefarnan@modelengines.com.au
MELBOURNE 3166, AUSTRALIA
Is this for your ck boat? have you calculated the loads on it, cos you might get a shock!
Luff 'em & leave 'em.
Micheal
You can get new gears for these but as Matt says I would check your loads if you are using it for the keel. As on my F100 the loads on the lever are a lot more than what you would think. I calculated that I need around 9kgs of pull at the top of my 100mm lever through the boat and am only canting about 1.6kgs
any way hope this helps
cheers gappy
Mine (i think, off the top of my head) was around 3kg for a 500g bulb, and I felt that was pushing it for the hitec winch I used, hence the water bottle lifing test (look back in the archives, its in one of the canting keel trainer threads).
Luff 'em & leave 'em.
how do u work out the load?
keel is about 1kg all up
about its 40cm long
planing to cant to 45 degrees
Something Is Nothing and Nothing Is Something!
<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>Originally posted by yachtie2k4
how do u work out the load?
keel is about 1kg all up
about its 40cm long
planing to cant to 45 degrees<hr height=“1” noshade id=“quote”></blockquote id=“quote”></font id=“quote”>
From the Hitec Web site for the HB725: Torque 4.8/6.0v : 161 / 201 oz. 11.6 / 14.5 g
So, using 6V, it’ll hold 201 inch-ounces, or 14.5 kilogram-centimetres (they haven’t annotated this correctly, but that’s what it should say).
For simplicity, let’s imagine your keel is canted 45 degrees while the boat is heeled 45 degrees, so you are hanging 1 kg straight out on a 40 cm lever arm – the torque being exerted by the keel wanting to come back to the vertical is therefore 40 kilogram-centimetres. Ah, one stripped- or burned-out HB 725 comming up… (smile)
Note that the maximum torque quoted by a servo manufacturer is a holding (stall) torque. If you want your keel to actually move, then the servo torque must comfortably exceed the moment of the keel. Double the number would be about right. So it seems you are in the market for a 80 kilogram-centimetre servo, ignoring friction losses which are not negligible…
Let’s go back, and figure out the static load on the keel even when not canted. Let’s have the keel not move at all and just have the boat heel 30 degrees. Torque required is now 1 kg (keel) * 40 cm (lever arm) * sin (30) = 1 * 40 * 0.5 = 20 kg-cm. Darn! This is around the stall torque of the RMG 380 or the Hitec 815. These servos would struggle just to hold the keel in place, never mind cant it…
Lester Gilbert
http://www.iomclass.org/
http://www.onemetre.net/
Lester the weight that you have calculated would be correct where the keel goes through hull structure and remembering that there will be a lever of some sort going through the boat it will then gain back someof the advantage that it has lost by having a long keel.
My keel on my f100 is 550mm long and the weight on the bottom is 1.6kgs and the lever through the boat is only 80mm and it cants it fine with a HB725 and it will cant up to 2.2kgs. This is running on a gear bulkhead rather than using the drum though but my last boat use the drum with the same keel and lever but had a 2:1 purchase on it.
Any way it will depedn on how big your lever is if you are using a purchase and how much friction there is in the pivot and the rest of the running gear.
Hope this helps.
Cheers Gappy
I’m not sure if anyone has considered it but wouldn’t the bulb weigh less under water? Maybe it doesn’t amount to much.
Thanks
Don
Vancouver Island
Don
From what i have been told you would be correct it is believed that the bulb weighs about 10% less under water. I have not check this out for fact but have been told by other guys looking into cantings keels.
Cheers Gappy
<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>Originally posted by gappy
My keel on my f100 is 550mm long and the weight on the bottom is 1.6kgs and the lever through the boat is only 80mm<hr height=“1” noshade id=“quote”></blockquote id=“quote”></font id=“quote”>
Yup, I wasn’t being very realistic in attempting to attach the keel directly to the winch! Let’s have the winch pull some string that is attached to the keel instead.
With your set-up, the lever arm ratio is 550/80 = 6.875, so anything pulling the 80 mm arm “sees” a weight of 1.6 * 6.875 = 11 kg. Let’s put a drum on the winch with a radius of 10 mm, and have the drum wind the keel in on a line. Torque here is 11 kg * 10 mm = 11 kg-cm, easily within the capability of a powerful winch.
If the drum makes 1.5 turns one way, and then 1.5 turns the other, total line travel is about 3 * pi * 20 = 188 mm, so you have enough (other things being equal and depending upon the location of the drum, the lever arm, etc) to pull the 80 mm lever fully over to one side, then fully over to the other.
Lester Gilbert
http://www.iomclass.org/
http://www.onemetre.net/
For the setup of my canting keel,I am using a 150 t module 1 gear quadrant attached to the hull (centre of gear on concentic to keel pivot) with a 15 t pinion gear driving the keel control arm around the gear quadrant. The sevro is attached to the control lever and drives thru the 15t pinion.
The worst case for load is when the boat is heeling and the keel is horizontal (not related to the angle of the canting keel.
With 1.9 kg of lead swing on a 515mm keel there a turn monement (torque) of 9.6 Nm.
The control lever length is 82.5 mm giving a force of 116 newtons, the pinon pcd is 15 mm therefore the holding torque on the pinon shaft is 0.87Nm. This is a small amount of torque because of the use of the gear and pinon setup.
Now we start adding factors to it, such as:
Canting keel bearing friction
Gear friction
Starting inertia
The dymanic force of the lead bulb bouncing on the end foil.
Safety factor.
So the required torque is
0.87 x 10% x 10% x 200% x 200% x 4 = 16.8 Nm
I am using a RMG 380HD winch with 20.7 Nm stall torque at 6 volts.
Talk about “Tim Allen” power to the toolman
Gunta is using this method in his Ultimate Warriors but the protype used a rubber wheel about 8mm dia rolling around an curved surface. There was a light flexible wire attached at each end of the curved member and run around the small pinon wheel, this gave the drive.
I have lost my pdf writer so I cann’t show a large size of the setup so heres a photo
Download Attachment: 
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John B MEWLT
(Mechanical Engineer who likes tweaking)
Ok.
If I had a canting keel, weight of it is 1kg, keel length is 40cm, lever length is 10cm what servo should I use, would the HS 700BB be able to cant it 45 degrees?
Rob
Something Is Nothing and Nothing Is Something!
JohnB
You may want to check your numbers…
If you have a 150T quadrant and a 15T pinion gear on the servo then you have a 10:1 gear ratio, so your holding torque must be 1/10th of the torque on the keel or 0.96Nm (pretty close to the 0.87Nm that you have calculated…).
As far as your factors go, many of them do not apply to the holding torque of the system. They do apply to trying to move the keel. For example, the friction of the canting keel bearing is only a loss factor if the keel is moving. If the keel is being held stationary, that friction is helping to hold it - not hurting.
It looks like you have applied some pretty conservative safety factors. That is good. You should not have any problems with the system not holding - at least as long as you have full battery voltage…
You probably recall the scissor arm system that I designed for my canting mast? If not, here is a sketch:
Download Attachment: 
64.03KB
This system is designed with the idea that the higher heeling loads occur as the wind increases. In those conditions, the mast will be fully canted to one side or the other (depending on which tack you are on). With this system, when the mast is fully canted, the scissor arm “locks off” such that there is no holding torque required by the servo to hold the mast in that position. This dramatically reduces the battery drain.
I have a spreadsheet that calculates the servo torque for this geometry for various degrees of cant and boat heel.
The build is progressing a little slower than I would like, but here are some pictures from a fit check that i did a few weeks ago (things have not progressed much since then):
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Download Attachment: 
79.54KB
So far the basic geometry seems to be working just beautifully. The fit check revealed a few issues related to the height of the boom and the rake of the mast that I have since resolved. I am now working on laying up the foredeck and keel trunk so that I can integrate the structure of the mast canting system into these other structures to allow a seamless transfer of heeling load from the sails to the keel.
- Will
(Aerospace Engineer how likes tinkering)
Will Gorgen
micheal
I would say that you would get away wioth using the Hb725 with a 2:1 purhcase on it you keel would not appear to be as highly loaded as ours. How big is the actual boat as on my F100 i am using between 1.6-1.9kgs haven’t quite decided yet and on my first one I used 1.9kgs this could hold a good amount of sail area up wind and down wind as well but you get into the trouble of truning the corner with to much area up and end up going for a submarine.
i am using Gruntas new style geared bulkhead in my new boat unsure of the teeth on it but i works great and the HB725 gives me exactly enough turns to gofrom full one way to full the other which has kept cost down slightly.
Any way hope it helps
cheers Gappy
<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>Originally posted by wgorgen
but here are some pictures from a fit check that i did a few weeks ago (things have not progressed much since then):
<hr height=“1” noshade id=“quote”></blockquote id=“quote”></font id=“quote”>
Ahhh Haaaaa ! [:-magnify] I spy the use of some very hi-tech, birch material! Popsicle/ice cream bar sticks and masking tape !!!
And I though I was the only one to use them !!![:D]
I admit that masking tape is not very Aerospacey… Popsicle sticks on the other hand are made from wood which as we know is a very high grade of composite material which was embraced by the aerospace industry from the very beginning (the structure of the Wright Flyer was in fact made mostly of wood!).
What you may not have spied is the use of RC car chassis components in the compression strut forward of the mast.
I do get Aerospace bonus points for the use of a RC airplane tail wheel assembly for the mast base. On the other side of the bulkhead is a 4:1 gear reduscer from an electric park flyer airplane as well. So, it seems like the high tech quotient outweighs the low tech quotient 3:1!!!
As far as the next steps go, the deck is the big next step. The deck is going to be fiberglass. I have made the basic mold shape and am working now on integrating a recessed jib rack pocket into the mold. Once I have the deck laid up, I will integrate the mast bulkhead and a stringer bulkhead running to the bow for strength. Once the deck is joined to the hull, things will be a lot more solid and should allow me to make some pretty serious progress (if I can find the time to work on it…).
- Will
Will Gorgen
Will and JohnB,
Thanks for posting pictures of your “gizmos” [:-magnify]. No offense intended I just like that name.
As it has been said a picture is worth a thousand words. Very nice, hitech productions you both have going on. I helps alot to see sketches and\or pictures to fully understand where you are headed and how.
Will, I for one know that the blue tape you are using is not standard masking tape but high end low tack tape. I would expect nothing less from you.
Tom
Seawind #80
Thanks Tom,
Wouldn’t want to to add any extra weight from that sticky tape residue. Must be low tack all the way…
- Will
Will Gorgen