Jump to content

Richard98

MYA Member
  • Posts

    122
  • Joined

  • Last visited

  • Days Won

    5

Everything posted by Richard98

  1. Derek, Like to see some pics of the boats here. Have used "Haslar" vane gear full size, but this is a trim rudder servo rather than the models (has more work to do) Would love to have a go at vane sailing, but no where suitable nearby - shame. Richard
  2. Great comments and I will try the Sails etc holders, Captain Scarlet. John; Worth explaining that I have actually no tangible problems, more of a suspicion and doubts. I was using a FlySky, that you mentioned in passing, on a carbon / Kevlar M and suspected loss of full control at distance. Do you think I may be better off using my other kit: Futaba T6J-FHSS TX ? If so I will buy another RX, in which case do you have a recommendation on the RX ?
  3. Very generous of you, John, and your diagnosis of the patient and donor made interesting reading. Nice to know where to go for these sort of problems. Richard
  4. Pic of Pieces of Eight sailing with a Starkers M, rigged as a 10R. Thought it liked nice. Richard
  5. I am looking for the best position of the two receiver aerials for carbon Marblehead. I have tried the underside of the deck patch, but was aware that this was not the best. I have read Lester Gilberts's article also. Is it worth siting in the screw lid of the pot ? I can see little evidence of aerials sticking up on pictures of boats. What is the common/usual arrangement ? Richard
  6. You've hit the nail on the head, John, regarding light airs performance. I have discovered, possibly the "B" obvious, that there are other factors that apply to shortening the WL that do not have the same relative effect at full size. I also suspect that a Marblehead is the way to go, as you have done. I have sailed Pieces of 8 with a One Metre (2.3Kg) ballast ,on max length fin, in light winds and seems to work ok. I began to look at wing sails and there are plenty of scale modellers who have made them. But not to race. I wanted a full wing shape with hinged trailing edge. Super efficient but also super complicated. So many bits required to maintain the camber all the way up that the whole thing becomes too heavy and complex. Once again; so much easier full size. Popping a semi soft sail is tricky and takes power off just when you need it. I like the pocket luff rigs and there is scope to develop in that area. What happened to your Gothic hull ? Did you build over a foam core ? Any pics ? The reason for my interest is my dormant project for a foiling hull. The old carbon Kevlar M hull that I acquired as a "skip job" has too much volume and is a very old design. Wish I had not sold my Starkers, also acquired as "needing work". Have you tried a lighter ballast on the Starkers for light winds ? could be interesting.
  7. 10R design options once more: My Pieces Eight represents one extreme design and I would like to look at the other: Max Wl / min Sail area. I do wholeheartedly agree that the top 10R's excel in all conditions but the class allows so many opportunities for experimentation that it is difficult to resist. One of the attractions of the Mini40 also. So what designs stray in that direction ? The aspects of our scale are so different to full size; particularly with respect to wetted area and possibly block coefficients. Here I am looking for any evidence for / against hull types for the 10R. Another boat to build ?? Frank Russell's Gothix perhaps ? Quick comment on the rules. I was part of Team New Zealand and remember the rule "discussions" that took place in court. Also the measurement process that meant cutting large holes in our expensive and painstakingly made hulls. PS. I do sail Richard
  8. Been doing just this with the Pieces of Eight. Very aware that the full 700mm is only just sailable where I sail. Have reduced ballast to 2.3Kg from 3.6. Reduced ballast has shortened the WL; will allow more Sail Area (SA) . Reduction in volume of ballast and Wetted surface area (WSA) is a plus. WSA is reduced twofold; on the ballast itself and the reduced underwater hull volume / area. Have not tried a shorter fin, but if I retain the same ballast then WL and hence SA remain the same but: The small reduction in volume with the shorter fin will make a small difference to the boats performance. Reduced wetted area and volume ; small I know. A small reduction in weight will, microscopically, reduce the WL. There will be dynamic differences also but these are so complicated to analyse. Don't even start on block coefficient in relation to reducing volume and hence WL. Really important question on an extreme design like Pieces of Eight. Also the skin friction having far greater, relative, effect at our size than full size. Need a test tank ! So many questions. If going down the two fins route, would multi certificate the boat, as Solent's comment. Allowing a SA tolerance to cover both options. Richard
  9. I have also been using King Max 61G winches for quite a few years now. One Metres, Marblehead, "special" 6M, Mini 40 and currently on my "pieces of eight" 10R. The new version, 68G has more torque, is a bit faster and Waterproof. I have done a quick calc using One Metre sheeting length and 6Volts for both. Sheeting times are: 61G 1.71 secs - 68G 1.49 secs. Torque: 14.5 - 17.8 Kg/cm respectively. Each using the new metal drum, 30mm dia, and a great improvement over the old plastic one 25mm dia. Adds an extra £6 but worth it. BUT !!!!! £27 now £47 However looks as though the 61G may not be available now. Still cheap though. Richard
  10. Have been contacted, through my website, by the owner of the boat described here. The pictures show a very nice wooden hull. The dimensions make it one of the larger classes, obviously. Possibly the horse box shown is used to transport it ! Dimensions (approx) in inches Loa 68", B 11", D 16", Mast above deck 69". Wt 7Lbs ( I know; does not seem a lot) Any ideas ? Richard
  11. Hello Nancy. Pikanto is a great boat from Graham Bantock and if you visit the Sails etc web site you can download the Pikanto drawing. This shows the dimensions to allow easy checking of the keel rake. Maybe you have just been mis informed and there is no problem. There should be a label moulded on the inside of the hull with details and I would be very surprised if there was an error in your hull. Please post your results and, if necessary, can think about how to modify. Good luck ! Richard
  12. Back again ! Paula I really understand your comments and complex rules can appear intimidating. Unfortunately in this "cheque book" sport philosophy these days, all the classes have lawyers keen to exploit vague rules. I had a few items on the 10R rules that were simply explained by some, more familiar with the class than me. I have become a firm fan of the class; never having raced one against another yet. I am a sailor that enjoys the design aspects and the consequent experimentation with development classes. The 10R offers the greatest scope and ease for such experimentation. I liked the comment from Brad that he builds a tolerance / safety factor of some 4-6mm WL on his designs, this makes so much sense and does a lot to encourage amateur efforts and avoids owners who demand gramme / mm precision and expect to argue with the measurer. I have built boats for owners who specify such requirements. This forum provides access to a wealth of knowledge, that I have gratefully plundered. Anyway; good 10R sailing, Richard
  13. Wow !! did not expect that. Last post then. Richard
  14. Here we are at last, sailing with full top rig. I have thoroughly got the hang of the 10R spreadsheet, thanks John. Sail area 1.083447 and a rating of 9.97 achieved. I have played with the spreadsheet to optimise the trimming required to suit the balance of the boat. I have marked potential reduction should the waterline not be spot on. Easy ! Pictures here with usual ghosting breeze Richard
  15. As a newcomer to this class I have now become quite familiar with the measurement spreadsheet and, ironically, now cannot see why I had problems initially. This forum has been so useful and through my thread as "potential 10 sailor" I am very grateful for the assistance and advice received from members. I must single out John; whose efforts pointed me to the error I had been making. This is the true value of this forum. I not only see a great attraction in the 10R class but find myself impressed by the spreadsheet. The errors referred to earlier are, however, irritating and maybe some sort of enhanced guide to it's use would not go amis as I also spent time trying to eliminate them. Only thing to sort out now would be a simpler keel depth measurement procedure, which would surely result in more measurers. Richard
  16. As Martin says; delrin may be a better bet. Nothing wrong with Tufnol as a bearing material though. I vaseline the rudder stock before fitting, which will do a lot to help in many ways. Interestingly brass will de-zincify quite happily on its own. Richard
  17. Update to my last: Thanks to John I have discovered that the spreadsheet I have been using, downloaded in December, was out of date. It was version 5 and the current version is 6B. Frustrating or what ! Unfortunately I am still getting a huge error in my sail measurements compared to old fashioned geometry calculations. Will persevere, of course. Have now spent more time on sail measurement than it took to build the 10R hull. Maddeningly I am aware that it must be something I am doing something wrong However it is interesting that I can reduce the Sail area without incurring error messages by leaving out a few measurement values.
  18. Thanks Solent, I did that before I started. Thanks to John sending me a copy of his calculation forms I have realised that the forms I downloaded from the MYA IRSA page were not the same as his. Hence my earlier comments about the Sail 2 page having the same title of "Sail 1" and showing the picture of the Main. I just assumed that this was a generic sail shape. I have just re visited the same source and downloaded the spreadsheet again and it is completely different. Now I have the same as John. Sort of irritating that the form I downloaded back in December was so different and I have spent two days finding out. Anyway; will try again in the morning. Taking note of the "fudge" that appears to get rid of the error messages because the spreadsheet cannot count from 0. Appreciate all the help here. Richard
  19. Thanks for that, John. I have now substituted value 1 for h0 mainsail and 1 for h9 jib, instead of value 0; and errors disappeared. Hooray for that. Spent some time trying to make sense of the mast and spar form and sort of got a figure with no errors. However my total SA is way out. Have checked the old fashioned geometry way to confirm this. So difficult to follow the form. I know a spreadsheet is going to make life easier for a class with variable sail areas like the 10R; but it is so difficult to understand what is expected. As I said, I have made a few assumptions just to get started. I know that anyone who has successfully done it once will laugh at my problems and I am a bit cautious about expressing any strong opinions. Samples: why does sail 2 total have a title "Sail 1" as does sail I ? What is spar 1 "E" measurement. and quite a few more. I am using Excel for Mac 2008, which is the same age as my MacBook. Works ok for everything else I do. I have been looking at the formulae in each cell but that is all. I feel the fault lies in the data I am entering, but cannot find out what yet. How did they measure the sails before Microsoft appeared ?
  20. Just getting around to the A rig now. I did the initial flotation with a dummy weight; adding a little to that last rig pictured. As you say, this is going to be iterative. Not going for outright maxing out on the rule at the moment though. Pof8 has longer overhangs than Bentley, having LOA of 1930. Just like the J's of old and should heal to a greater wL as a result. I use the word "should" because I have not got any generated waterplane lines and have to wait for a nice sailing wind and see how it looks. Have hit one problem with sail measurement though. Expected no problems here and made the measurement grid and took all the relevant measurements. Appears straightforward until I tried entering the data on the IRSA spreadsheet. After having to make a few assumptions from a spreadsheet that is not particularly intuitive, I began. Mainsail worked ok but when I entered the data for the jib I keep getting an error message. "Foot length does not match number of heights". I did get that with the Mainsail also, initially, but found the error. I have spent hours trying to resolve the jib error and have got nowhere. I know this must be a simple mistake and Have been back through the database figures and studied the cross width diagram; all to no avail. Is there any guide for this ? Have I Hijacked my own thread ? Should I stick to the One Metre ? Brain hurts.
  21. Hi again Trevor, Your technique for applying tow works. I wind a couple of turns to achieve a single layer of flattened tow. No need to cyano the free end, just cyano the start, wet out, wind on and tape over with electrical tape. The woven sleeve is cleaner, simpler and less bulky where a run of reinforcement is necessary; say 10-20mm or more. Bulk may impact on the sail to mast clearance unless very careful. Sleeves are 1mm wall and this is very easily exceeded with tow. Sorry if this sounds repetitive, but there is no need to over wind tows. A single thickness winding is sufficient. Also adds weight. I peel ply to remove excess epoxy, but this is a bit paranoid ! Sounds like you have a serious amount of splitting and I possibly see why you would want to wind on with a lathe. You must have a "proper" workshop. Richard
  22. I would like to add / reply to the recent comments here. In order: John; just looked at Graham Bantock's gauge that you referenced. My idea was also a floating gauge. A length of wood floated alongside the WL with a right angle fixed at one end and sliding the other. Sharpened "jaws: set to declared WL and used as a simple Go / No go gauge. Derek; Pieces of 8 hurtled across our lake and several spectators asked what was powering it. I had difficulty keeping up with my iPhone to video and steer at the same time. Very impressive, particularly as Have been investigating speed sailing for a long time now. Brad; No hijack at all and keep it coming. This boat was deliberately built as an extreme end of the rule for a reason and has resulted in me becoming interested in the class. Darin; From previous I have distilled the following results out of data from Pieces of Eight and Bentley designs; summed up below. WL 1150 & 1344 respectively Sail area 1.08695 sqM & 0.93005 sqM this is a difference in allowed max area of 0.1569 sqM. This may not sound much in sqM but is 1569sqCm and this equates to > 39 X 39 cm of sail area allowable difference in area for the two designs. Amazing or what ! I think your specific 5mm is easily extrapolated from the rule. Add to all this is the actual shape variation available to designers and many, many characteristics to play with. I don't think I have a measurer nearby so I will incorporate a tolerance on sail area and WL to ensure that I know the boat will be legal but not necessarily fully optimised to the rule.
  23. Hi Eric, nice to hear from you. Roger uses an offset mast fitting on his swing rigs and this allows conventional sails to be used. The 10R class seems to favour conventional rigs, based on all the advice I have received from those experienced in the class. I will be going that way and consequently do not even have a swing rig mast tube. The Pieces of Eight has the mast in the correct position as a result. I checked out a few designs and found the mast / fin relationship pretty much standard as is the main / jib ratio. Actually a simple class to put together; well, just as straightforward as a One Metre anyway. Standard mast / finbox mouldings are available which further removes any guesswork.
  24. Wow !!! this is suddenly so interesting. You are both correct, of course, concerning the design extremes and relative virtues; or not. I did consider Bentley, but that was the polar opposite of what I needed for something to suit the very light conditions that I usually sail in. Also the boat was built to a tight (very small) budget. My brief foray into the 10R class has stirred my interest in a boat that allows true performance with a fairly simple rule and, very important, not a lot of weight to cart around. The overhangs introduce huge scope for hull tuning since they are not tied to the simple WL formula as they must be designed to heel to an optimum WL; or sail flat in light winds well below hull speed. Aiming for the best of both worlds. These boats must be the most exciting class out there. Why on earth the class has not got a greater following is sad. I have built a few Mini40's and the same comment applies. Although to be fair you have to invest in at least two hulls there. Neither class has a useful web site or forum with any discussion (apart from the MYA here) The Mini40 only exists on Facebook and the British Model Multihull website has been out of use for ages. Nowhere to gather info or discuss two classes that should be generating more discussion than most, due to their many diverse performance characteristics. I would love to get my hands on a current design, but my Pof8 provides some fun sailing at least. I think I would go lighter ballast on longer fin, thereby reducing the displacement and all the consequent form drag. Appreciate that this may limit some venues. Measurement: As pointed out, should not really be a problem. Totally agree about WL being the most critical item WL. Tried various tricks short of getting into the water myself. I used bright tape with increments marked and then photographed, sort of nearly consistent. Even thought about the foil and battery mentioned. No tank though. Adding surfactant to the measurement tank would decrease the meniscus, but hey ! getting a bit chemical here. What about a floating gauge, sharpened to a point and pre set to the boats declared WL. Go/No Go. Could be used at the water side, if calm, and the draft subsequently measured. Thanks for your appreciative comment, Brad.
  25. Another sail, this time with a taller, higher aspect 10R rig - thanks John for the sails. Still some area to add though. Richard
×
×
  • Create New...