Dragon Force Replacement Sail Winch

[David Foster]

One for the Committee, possibly.

The latest replacement winches supplied by Ripmax (UK - in official Joysway packaging) are different from the original ones! I haven't had the opportunity to compare their functioning for speed or anything, though there doesn't seem to be any obvious difference in performance.

The difference is that they are supplied with a single drum, rather than the double drum on the originals and the ones originally supplied as replacement parts. The outer guard is also shallower to suit the new drum. I can see the logic from Joysway's point of view, as the single drum is shallower and makes the top of the winch lower and eliminates the danger of the drum fouling the deck patch if a third party, sticky, deck patch is used.

Probably nothing to be done about it, but I thought you should be aware, in case there are any significant differences (which there don't appear to be from a quick glance).

David.

[Chuck LeMahieu]

The Gang of 3 already ruled it legal since its a manufacturer part, but it should maybe be added to the Tips section ;)

[David Foster]

Chuck.
The only problem with relying on a blanket rule saying that it is legal if it is a manufacturer's part arises if the manufacturer significantly upgrades the part. Just suppose they had decided that the original sail servo wasn't up to it and substituted it with one that was significantly faster and more powerful. There would suddenly be a large number of winch 'failures' so that a replacement could be installed!

In this case, I don't think there is any real benefit from using the new one, but think an eye should be kept on such things, just in case something like that does happen in the future. Presumably, the next batch of boats will come with the new sail servos installed.

David.

[Joanne Sharpe]

Hi David,

I think we have to accept that there will be some specification creep over time. The alternative is to be backing a product that isn't doing well for the manufacturer and I suggest that that's a road to no where.

We should bite the bullet and accept that Joysway want to develop the product because it's a success.

I've almost assumed that I'll be re-buying stuff as a matter of course while I stay involved in DF racing.

Let's face it, if you do a refit once a season, it's still going to be nowhere near the cost of buying a new boat in another class. Add to that the fact the nobody can come along and introduce the latest must have go faster product (like a Britpop!!), and I think we're in a pretty good place.

Take care

Joanne

Psstt. If you do find a wizzo winch that's in the rules, please let me know first hee hee.

[Tim Long]

Hi David,

The height of the drum is the only difference, it was introduced to stop the possible binding issues of the drum on the hatch patch.

Initially the drum was used because it was what Joysway were already producing, however having monitored the success of the product in the world market they decided to tool for and produce a single height drum.

Those involved in the project met with the manufacturer last week and we have talked about this upgrading of components and it is being managed by them so as to keep everything as standard as possible.  It may come to pass that the drum is available as a replacement item on its own.....should you fancy one!

Cheers

Tim

[tony...@elmclose.co.uk]

I have been supplying this lower drum for the last 18 months. I have sold 130 of these type of servos with only 4 failures. I was expecting many more.

They are all coming from the same source. I think Component shop sell the Dragon winch as a 1.5 turn servo showing the taller drum housing. They also sell 2,4 & 6 turns. It's the same servo with different gearing.

As there is no label on the winch, the simplest way to solve this problem is to set a standard time to pull the sheet in 100mm under no load. My test gave 1.7sec at 6v

It will be easy to check on the bankside if their any arguments. One of my digital servos could replace the existing as it looks the same from the top 0.3sec/100mm @ 6v


I am more than happy to test three dragon servos from a 6v bench supply as a reference.

Tony

[Joanne Sharpe]

Tony,

"One of my digital servos could replace the existing as it looks the same from the top 0.3sec/100mm @ 6v"

No. Only if you want to run a Dragon Force as a development class RG65.

Tony, please don't spam this forum

Joanne

[tony...@elmclose.co.uk]

Hi Joanne.

What I was doing was to show how simple it would be for somebody to cheat.

I know what servos can be used to replace the existing as I have tested 13 out of the 23 drum servos on the UK market.

My suggestion of using 1.7sec/100mm as a standard is a simple and easily checked.
Can you come up with a better solution?


Tony

[Joanne Sharpe]

Hi Tony,

You're not showing how easy it would be to cheat at all. Why is it that every time you post, it seems, there has to be a mention of what you sell and a criticism of something relating to Dragon Force?

Two provisions in the rules for Dragon Force racing are:

Spirit of the rules to be adhered to.

Only eligible winch is supplied by the manufacturer.

The Dragon Force rules are simple and designed to keep costs to a realistic minimum and encourage sailing skills and enjoyment, not an equipment arms race.

If you carry on like this, all you will achieve is a poor reputation in what is the fastest growing sector of radio sailing on the planet

Joanne

[David Foster]

Tim.
Thanks for the explanation and confirmation that Joysway are aware of the desirability of not materially enhancing the product.

I will stick with my double drum for now, as I remounted the servo under the tray when I put it back in after sealing the ply tray. The only disadvantage is that I will be hard pushed to do a winch swap between races now, as the tray has to come out first! If or when I need to change it, I will probably revert to mounting the winch above and using a single drum.

Tony.
I hope that you aren't suggesting that people go off and buy digital servos from you that look the same. As I am sure you are aware, the DF class rules very clearly  and expressly forbid such a thing. If anyone has reason to doubt a boat complies with the rules during the course of a meeting, the facility is available to check whether a boat complies or not.

If you want to just cruise around in your DF, or enter an RG65 open meeting, then please feel free to put whatever kind of servo in that you want.

Joanne.
Well said.

David.

[RG65 UK NCA]

David

 

the single drum is a legal modification. we discussed this with joysway when we met with them last week

 

regards

 

Mark

[tony...@elmclose.co.uk]

The main and jib sail sheets are attached to the sail sheet clip nearing the completion of rigging a Dragon. Here in lies a problem. The servo travel varies between boats.

I spent a long time trying to adjust the sheets on my first Dragon to give the correct sail/boom movement. In the end I gave up and added a “Servo Stretcher”. No problem now to set the sheet travel to 110mm with quick and easy travel adjustment. The Bowsies allowed for fine adjustments.

During my forth Dragon rigging (for a club member) I noticed that the servo sheet travel was larger but I still added a stretcher as it removes all the hassle.

I have just tested four Dragon servos to understand what’s happening.

The first test was to check the receiver output range for channel 3. Ranged from 0.97 to 0.99msec 0.98 +/- 0.01 = 1%. Receiver was not the problem.

Second test was to check the sheet travel from 1.0 to 2.0ms = 85, 97, 98, 104mm. This fits in with my original findings.

Lastly I checked the sheet travel speed. All my sheet speed values are given in sec/100mm as this allows for different drum diameters and rotation.

85mm   – 4.7s = 5.5 sec/100mm

97mm   – 3.3s = 3.2

98mm   – 3.3s = 3.4

104mm – 2.3s = 2.4

This sheet speed variation is significant but does it make any noticeable difference in sailing conditions?

Tony

 

[Joanne Sharpe]

Hi Tony,

"Herein lies the problem"

What 'problem' is that? Has this 'problem' stopped any of these boats functioning properly - sailing?

The DragonForce rig is such that you can set the boat up to sail successfully with a full range of rig movements for quite a wide range of distances traveled by the sheet without using any adjustments that one might have available on the transmitter. You will see if you look back over past posts that Barrie suggested to one forum member that winding on some extra sheeting cord to bulk out the drum would increase sheet travel.

As far as speed of sheeting goes, as I'm sure you know from your extensive writings on the subject of 'captive drums', all drums are 'slow' when compared to say an arm winch. Some are quite quick e.g RMG, but then an RMG winch costs more than a complete DragonForce!

We adapt to what we are sailing. My Micro Magic has an arm winch and sheets much more quickly than my DF, so I sail it slightly differently.

I'm also wondering what range of readings you got for each of these four individual winches? They are after all analogue devices and subject to variations, so isn't it misleading  to state absolute values?

If these variations stop the boat being set up to sail through a full range of rig movements, then yes, it's a problem, but I shouldn't think they do.

As I've written in previous responses to you, there is no set of absolute values for DFs or as far as I can make out, any other RC yacht. If there was a perfect set up, why do we see World Class skippers constantly adjusting the settings on their boats? Wouldn't they just have a secret formula and leave it alone?

These boats are for sailing Tony and measuring winch performance won't help us improve our skippering skills

Take care

Joanne

PS, I'm sorry that I can't make it to your Open next week, but we have the Radio Marblehead Nationals at Keighley next weekend and I'm helping out.

[Joanne Sharpe]

Tony,

One more passing thought, as you're apparently setting up boats for other people.

I do hope these boats with servo stretchers aren't going to be raced in Open competition under the Restricted Class Rules...

"The boat will be raced as supplied with no modifications or additions apart from any permitted changes described in these rules"

and

"The Sail Winch shall be supplied by the Builder. No sail winch shall be modified electronically or mechanically from its factory default performance torque, speed or revolutions, except for those adjustments available through a transmitter"

That seems quite clear to me.  And even if they were within the rules, why introduce something that can fail in the heat of battle when the adjustments needed are inherent in the rig design ?

Take care

Joanne

[David Foster]

Hi Joanne.

I agree with everything you say in your first reply, but think you are mistaken in saying that 'servo stretchers' are illegal as far as the rules are concerned. They are not specifically mentioned in the rules, so would be illegal, except for the fact that 'Hints & Tips' specifically say they are allowed in order to make it fairer for those using the standard radio to have the same facility as available with most 3rd party radios. The DF rules specifically state that all Hints & Tips on the official website are considered legal modifications, so 'servo stretchers' must be legal.

Best wishes,

David.

[Joanne Sharpe]

Hi Tony and David,

Thank you for pointing out my error David and my apologies Tony for getting it wrong in the previous post.

I look forward to seeing you both on the water soon

Take care

Joanne