Model Boat Mayhem
Mess Deck: General Section => Model Boating => Topic started by: Bradley on November 28, 2009, 02:30:28 pm
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Here are the pics of my 46.5" Fairey Huntsman so far as I have got with it. The internal framework is more or less complete and is just laid inside the grp hull and requires adjusting somewhat and then glueing/fibreglassing in. {:-{
Derek.
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Hi Derek
Your Huntsman is looking good, please keep posting the photo's. What are you going to power her with?
Phil.
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Hi Phil,
Thanks for the kind comment. At the moment I am considering powering it with twin brushless motors. I already have 2 outrunners and am waiting for 2 inrunners to be delivered to try to work out which will be best. I am also going along with advice and, eventually, props, shafts, etc., from George Sitek ( http://www.gsitek-props.co.uk ) as I have always found him very helpful. All his props are individually made and I don't think his prices can be beaten. :-)) I will probably use rechargeable Ni-Mh battery packs as I am not too happy with Li-Po's and I don't think weight saving will be necessary.
Things might slow down a little with the Huntsman as I am trying to get on with my Cygnus GM33 but will post more photos asap.
Derek.
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Hi Derek
Nice to see your Huntsman will be electric power and brushlees to boot. Too many people seem to be scared of using brushless motors, I can't understand it as they are so very much more efficient and run a lot cooler as a result.
keep up the good work.
Phil
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Morning Barry! :-)
Which motors have you ordered? :-)
Martin.
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Hi Derek, Hmmm....... I can see from the pics your dilemna, are you going to A) pack out the somewhat 'shrunken' internal frame or B) cut down the moulding? Thats a hard choice? (is the size of the deck big enough to allow choice A?)
Sometimes you wonder if kit manufacturers ever actually intended for their products to be built? The stern of that hull looks nowhere near touching the rear of the very undersized framing. :o :-) (Thumbs up for trying brushless.)
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Hi Perkasaman,
In actual fact, once the forward cross members are cut down to size, the framework will sit down into the hull and then the hull sides are drawn in to the framework and secured. The hull sides are fairly flexible and pull in quite easily to the framework. Believe me, the framework will fit into the hull, it is just that, in the photos, it has not yet been made to fit and is just sat there loose. The hull moulding is quite a good one and appears to have been cut quite accurately, so no trimming is needed there. The deck is massively oversize and, obviously, has to be cut down so that when finally fitted there is a 1/8" overhang all round the hull. The instructions say that the hull sides should be drawn in, held in place (with rubber bands %% %%) and then secured with grp and resin - we shall see. {:-{
I think that this will make into quite an impressive boat but I think that Anglia Model Centre need to rethink what they are marketing. I believe that if some thought went into it and they upgraded the kit and added things like deck fittings, etc., and replaced some of the liteply framework with a stronger ply they would make it a more comprehensive, and popular kit (with an increase in price). Some of the die cutting of the ply leaves a little to be desired and I just get the impression that AMC have done no development work since acquiring the rights to the kits from SLEC many years ago, which I think is a shame. :(( I don't think that this is an undue criticism of AMC, just a comment on what (I think) needs to be done to make it into an excellent kit. ok2
The brushless motors I have at present are a pair of Emax 2826/06 outrunners and a pair of Emax 3540/16 inrunners - don't know whether either of these would be suitable so I shall ask for advice from the more knowledgeable members and, as I said previously, I am relying on the advice of Geoge Sitek re props, etc. :-))
Derek.
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I am looking for a supplier of brushless moptor esc before I make a choice of motors for my speedline 1/16 scale severn lifeboat. I woul;d love to fit brushless so where do I get the marine esc from?
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"....the framework will sit down into the hull and then the hull sides are drawn in to the framework and secured. The hull sides are fairly flexible and pull in quite easily to the framework."
Won't that distort the hull shape Derek?
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As I remember, on my 34 inch version, the hull fitted quite snugly, once the frames were trimmed to fit low enough, but it was a few years ago !!
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In actual fact, Martin, I have tried 'squeezing' the hull in the necessary amount and it was very easy. The amount it needs to be pulled in is quite small and does not pull the hull out of shape. As I mentioned previously, the hull is quite a nice moulding and I have no complaints about it whatsoever. :-))
So far as esc's are concerned, Mook, I am also searching. The only boat ones I have found so far are from China via eBay - http://stores.shop.ebay.co.uk/sellsincerely__W0QQ_sacatZsellsincerelyQ5fQ5fW0Q51Q51Q5farmrsQ5A1QQ_sidZ896818812?_nkw=seaking+esc&submit=Search.
I have bought a 35A one in the hope that it will be the right one. If it is then I will get another one. :-)
Derek.
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many thanks derek
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Here goes to try again - just tried to post and lost it all :(( >:-o
This is the stage I have reached today. Framework trimmed and temporarily clamped in place. You will see that the clamps have deformed the sides of the hull slightly but I am sure I can rectify this when I start to stick them together. I also find that the trimming of the hull (by the manufacturer) is not as good as I thought :(( and the top of the hull and the top of the framework do not quite match up but this will be reftified with filler when the deck is in place.
Has anyone any comments about the brushless motors I mentioned earlier?
Derek.
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Hi Mayhemmers,
Any comments on the brushless motors I mentioned earlier? :-))
Derek.
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Come on, guys, I thought we had some brushless experts on this forum {:-{ :(( {:-{ :((.
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dont know much about that particular motor but you may need biger speed controlers like the 80amp version rember you need a biger speed controler in water than air to be safe also do you know the KVA of the motor most motor suppliers quote it but I cannot find it for this motor. if its low ish it will be a great motor I would have thought.
Peter
http://cgi.ebay.co.uk/Emax-Brushless-Outrunner-2826-06-+-Emax-60A-ESC-x1set*_W0QQitemZ120462340555QQcmdZViewItemQQimsxq20091124?IMSfp=TL091124011004r11494
you will have to copy and paste
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Many thanks for the link, Peter. I have had a look at it and, from the information given, two of them would be powerful enough to get the Huntsman on the plane as it quotes them as being the equivalent of a .40 2stroke or a .60 4stroke. I will try to mount them so that if I need to go bigger then a change would not be too difficult. At the present time I am awaiting delivery of a marine ESC to give them a try. I have run them with an aircraft ESC but the programming (with music and morse code) was ridiculous and in the end I just gave up. :((
Derek.
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A lot of them have a program card that is very cheap makes it easy to do with one.
Peter
http://www.hobbywing.com/english/Product.asp?BigClassName=Accessories&SmallClassName=Program%20Card%20for%20BL%20ESC
may not do boats though ill look on offshore elec
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Thanks again, Peter. I have ordered a programme card with the ESC. Having found out what a stupid arrangement it was to programme the aircraft ESC I don't think I would buy another one without a card (or already having one).
Derek.
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Hi Derek, Remember to take every precaution when you cut down/profile the grp hull - face mask/gloves/arms covered - glass spelks and dust are a horrendous irritant/nuisance - I now set up a (noisy)wet/dry vac nozzle close by worksite to try and eliminate problem - it's nasty stuff -I'm scratching just thinking about it.
I put masking tape along the hull edge first and marked up this with a biro/fibre tip (pencil rubs off).
Biggest clanger of all was ( should have been my first job) I forgot to make an boat cradle to support/maintain the wobbly hull's level/symmetry while marking up/glassing in hull/frames and finally bonding deck and ended up building a twisted/corkscrewed hull - that boat always needs an offset rudder - ruined - impossible to repair/correct. I'm sure you already realise these wrinkles but I certainly did'nt. This unfinished decked Higgins Pt boat hull is a testbed for my ideas and a reminder :-)
I'm sure modellers would pay extra for an improved kit of this very 8) popular boat.
(A lot of these non boat brushless esc's don't reverse) This is a great thread. :-))
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hi there derek i used one of these in my huntsman,35 inch hull.
http://www.giantcod.co.uk/hobbywing-seaking-reverse-program-brushless-p-403647.html
http://www.giantcod.co.uk/ezrun-3300kv-bushless-motor-p-403300.html
i ran it on 2s lipo,i used watercooled coil on motor,
the esc comes with watercooling
how fast you want the huntsman to go ?
to work out the rpm of a brushless motor,i.e. 980kv = 980 rpm per volt u put through it.
i used 3300kv brushless motor which i put 8.4v through it,so 8 x 3300kv/rpm = plenty of fun
i also used this setup in a 39 inch perkasa,
hope this helps
jabba
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Many thanks Perkasaman and Jabba.
Fortunately I do not have to cut or sand any of the grp. The problem is that the sheer line of the hull has been cut very slightly too deep so that, towards the centre of the hull it is lower than the top line of the framework by about 3/16" (hope that makes sense {:-{). So what I will have to do is a little bit of filling (NOT filing) after the framework is stuck in place which I did not want to do as the gelcoat finish is excellent but I suppose a painted trim in a contrasting colour will hide the filler.
I may be wrong, Perkasaman, but I thought that all brushless motors were reversible. It just appears that the market is flooded with aircraft ESC's (forward only ;)). There are some car ESC's which have F-N-R and some boat ESC's are now appearing on the market. I get the impression that one Chinese manufacturer of boat ESC's withdrew the higher powered ones from the market, I believe because they had a fault, and it looks like the replacements are just beginning to appear.
Thanks for the Giantcod links, Jabba. I was already aware of these but am awaiting a delivery of a purchase via eBay at the moment. I think that the brushless motors I already have will be powerful enough as a pair to get the boat up on the plane and running at a realistic (and satisfying) speed.
Once again guys, many thanks. :-))
Derek.
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Many thanks, Perkasaman, for the tip about the cradle. I had not bothered up to that stage and just plodded on with the hull and framework. Thinking better of it, I made a cradle this morning and the hull sits into it perfectly without any twist whatsoever :-). The cradle was easy - all straight lines :-)).
Derek.
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How's your Huntsman coming along Derek? Have you decided on a motor yet?
Christmas came early for me today. A club member gave me a Precedent 34 wood Huntsman :} :} :} (thank's Fred) Boy was I pleased, for may years I've wanted to build one of these and for one reason or another not got around to it. And to be given a Huntsman. The boat needs some tidying up, I don't think it has even been run before but spent a lot of time waiting for some TLC.
So I'm now searching through all the Huntsman threads getting all the information I can.
Phil.
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Hi Phil,
Thanks for your interest in my Huntsman. I'm afraid that things have come to a halt at the moment as SWMBO (or SWTSMBO - she who 'thinks', etc. etc.) has decided that she needs her kitchen for our family and friends over the forthcoming Christmas period :(( and the workshop (shed) is in full use for the Cygnus fishing boats :-)).
The motors that I have at the moment are (1) a pair of Emax 2826/06 outrunners and (2) a pair of Emax 3540/16 inrunners, but I have not decided which ones to use. The one advantage is that they both use exactly the same mounting so would be easy to switch over.
The building instructions for the boat show the motor/engine mountings too far forward for my liking and I am waiting for a prop and a length of shaft from Sitek so that I can work out a more suitable position. Obviously, on the full size Huntsman the twin diesels were mounted under the cockpit floor but it depends on the angle of the shaft as to whether I will mount the electric motors in this position.
Let me know how your refurbishment goes and post some photos - we all like piccies :-)) ok2 ;)
Derek.
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Hi Derek
SWMBO just don't understand do they {-) Whats a Cygnus fishing boat?
Wow, your going to fit two motors, very cool. Have you thought about battries yet? NiMi or LiPo? Should have plenty of power though if you can find enough capacity for a decent run time.
I will post some photo's of my Huntsman soon
Phil.
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Hi Phil,
I intend using NiMh packs which should give me plenty of power and run time.
If you have a look at this posting you will see what the Cygnus fishing boats are like. No photo of mine there but some great ones by mayhemmer Ray111 -
http://www.modelboatmayhem.co.uk/forum/index.php?topic=21091.0
Derek.
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Hi Derek
I see what you mean by a Cygnus now, very nice :-))
I saw the You Tube video of the very fast Cygnus as well %%
Thanks
Phil.
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As promised, some photo's of my Precedent Huntsman. The boat is in reasonable shape, the main issue the crack in the transom and rear hull sheeting on the "V", some bits of trim have fallen off or broken. Nothing serious. One observation and I'm not sure if it shows up the picture is the prop shaft tube looks set at a very steep angle and a long way back from the prop. Maybe thats how it should be but I don't have the plan to check.
Phil.
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Oh yes no I've posted the photo's I've remembered something else, there is a big lump of lead in the rear of the hull, I intend to replace that with batteries as I don't like carrying around weight that does not earn its keep and the motor mount position looks a long way forward. I reason that if the motor moves rearwards then less weight will be needed at the back to balance correctly.
Phil.
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Looks like that will be a nice boat when you have finished the refurb, Phil. :-))
I have another problem now {:-{ - I have got the brushless ESC and programming card and could not get the motor to run properly after several attempts at programming - I could get it to run ahead but after about 10 seconds it stopped and I could not get it to run in reverse. :(( However after a little advice from elsewhere I tried the programming again, both with and without the programming card and it seems that there is a problem in reversing brushless motors in that, after running ahead, I found that it would reverse by flicking the throttle stick on the Tx down several times. {:-{ I think that this is no use on a fast boat so am considering reverting to thoughts about brushed motors, eg. Graupner 700 or similar - any thoughts anyone, please?
Derek.
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Sorry about all the bold print on the previous posting - did not work out as intended. {:-{ :((
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sounds like you have a delay turned on, some have it to save controllers getting a blast of current while still going forward, I have player with 3 with reverse the first two cheap ones where a problem to set up and turned out to be to powerfull with the motors I had but reverse was there when needed, the other type are a lot dearer you can set them up in two min and they are so smooth in forward and reverse I will never buy cheap brushless controllers again go for castle creations
http://www.castlecreations.com/products/products_boat.html
Peter
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Many thanks, Peter, that gives me another line to work on. There is a Giantcod link earlier in the posting and the illustration of their ESC looks identical to the Chinese one I have been trying to set up.
Derek.
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Wow, just had a lookat the castlecreations website. I have no doubt that they are fantastic ESC's but the prices :(( {:-{. I'm afraid I would have to give up my hobby before I could even consider affording them. :(( {:-{
Now got to start thinking more along the lines of brushed motors (Graupner700 ???), etc. O0
Derek.
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Hi Derek, You have a large hull and have single prop/ double prop options. Best contender single prop is probably the MMB 900 on high volts. Best motors on twin layout are probably 700 BB turbo running 2 x 45X props at max 14.4v. These brushed conventional options are cheaper proven performers. Siting engine(s) more forward in the hull enables a more efficient horizontal axis for shaft/prop alignment to deliver optimum thrust along the keel. Many large fast coastal craft deliver thrust at quite acute shaft angles because of expediency/limitations of inboard machinery. Our bow/hull shape obliges planing conditional proprtionate to forward speed. A prop at any angle other than horizontal impairs it's effiency/presentation to the direction of water flow. Power tilt/trims tabs/wedges all enable tuning of good/bad designs alike.
The worst designs exacerbate these thrust issues when they are planing - The RTTL is an example of this contradictory design.
High output NImH packs are getting cheaper and are more multi useable and offer great weight saving/easier placement with both layouts. I sympathise Derek ,you've got some hard decisions. O0 A great thread. :-))I doubt whether I've actually helped/made it easier. :D
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One observation and I'm not sure if it shows up the picture is the prop shaft tube looks set at a very steep angle and a long way back from the prop. Maybe thats how it should be but I don't have the plan to check.
Phil
The plan for the 1/8 scale Huntsman has the prop nut 200mm back from the end of the keel, so this measurement should be 145mm on the smaller model. Yours does look a bit too far forward.
FLJ
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There is also the option of 2 x MMB 900's on 12 volts.
Bob
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One observation and I'm not sure if it shows up the picture is the prop shaft tube looks set at a very steep angle and a long way back from the prop. Maybe thats how it should be but I don't have the plan to check.
Phil
The plan for the 1/8 scale Huntsman has the prop nut 200mm back from the end of the keel, so this measurement should be 145mm on the smaller model. Yours does look a bit too far forward.
FLJ
Hi FLJ
Thanks for the measurement but I believe this model is smaller scale than 1/8 at 34 inches long I guess nearer 1/12 scale. What I did mean to say is the end of the prop tube looks too far forward. I think I will remove the tube and fit a new one further back and at a shallower angle.
Derek
I would persevere with the brushless. I have very little experience with brushless in boats so far but I do have quite a bit with brushless aircraft. I will never go back to brushed motors now, the gains with brushless are so big it's just not worth messing around with brushes.
This weekend I tested a boat (SHG Shadow) that last time out several years ago had a Graupner speed 600 motor fitted, the boat went OK reasonable speed but motor got very hot. I fitted a brushless outrunner (£20) that is the same diameter but half the length of a 380 motor and I used a cheapo chineese aircraft controller (£13) with no reverse, boy did it go, the boat could not handle more than half throttle but it was planing around the lake nicely.
My Huntsman will defiantly be getting a brushless and a similar controller to what I used in my Shadow but maybe with a water jacket on the ESC.
Phil.
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Hi FLJ
Thanks for the measurement but I believe this model is smaller scale than 1/8 at 34 inches long I guess nearer 1/12 scale.
No need to guess any more - it is 1/11 scale. A 31' Huntsman @ 1/12 scale would be 31". The measurement I gave was calculated as 200 x 8/11 = 145. You can take my word on this - I designed both of the original Precedent kits 8)
FLJ
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So where does the prop shaft go on a 1/11 scale Dave ? {:-{
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Hi Guys,
Many thanks to all of you for your contributions and suggestions which are all helpful :-)). Now to some head scratching ;).
All suggestions greatfully received :-)) :-)) :-)).
Derek.
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No need to guess any more - it is 1/11 scale. A 31' Huntsman @ 1/12 scale would be 31". The measurement I gave was calculated as 200 x 8/11 = 145. You can take my word on this - I designed both of the original Precedent kits
Wow, thanks FLJ, talk about the reply from the horses mouth :-)) This must be one of the most longstanding boat kits and still in production!!! Nice design FLJ and I hope you make money from it.
A quick measure of my Huntsman and guess what, the end of the tube is 200 fromm the end of the keel. Looks like somebody got their measurements wrong. 145mm looks much more like it.
Thanks
Phil.
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Hi Derek, You have a large hull and have single prop/ double prop options. Best contender single prop is probably the MMB 900 on high volts. Best motors on twin layout are probably 700 BB turbo running 2 x 45X props at max 14.4v. These brushed conventional options are cheaper proven performers. Siting engine(s) more forward in the hull enables a more efficient horizontal axis for shaft/prop alignment to deliver optimum thrust along the keel. Many large fast coastal craft deliver thrust at quite acute shaft angles because of expediency/limitations of inboard machinery. Our bow/hull shape obliges planing conditional proprtionate to forward speed. A prop at any angle other than horizontal impairs it's effiency/presentation to the direction of water flow. Power tilt/trims tabs/wedges all enable tuning of good/bad designs alike.
The worst designs exacerbate these thrust issues when they are planing - The RTTL is an example of this contradictory design.
High output NImH packs are getting cheaper and are more multi useable and offer great weight saving/easier placement with both layouts. I sympathise Derek ,you've got some hard decisions. O0 A great thread. :-))I doubt whether I've actually helped/made it easier. :D
Hi Perkasaman I think you need a new book as the Peter Du Cane - one is no good for the design of the hull of the Fairey Huntsman or the Swordsman (totally different rules) they are deep ‘V’ hulls and the RTTL is a flat ‘V’ hull – so different propeller shaft angles. Also there are different hull trim angles – try the book Milestones in my design by Renato sonny Levi – he designed the offshore power boat Surfury.
Aye
John e
bluebird
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No need to guess any more - it is 1/11 scale. A 31' Huntsman @ 1/12 scale would be 31". The measurement I gave was calculated as 200 x 8/11 = 145. You can take my word on this - I designed both of the original Precedent kits 8)
FLJ
How do you come by "strange" scales...is the desired model size decided on first and then worked back to the full size for the scale?
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How do you come by "strange" scales...is the desired model size decided on first and then worked back to the full size for the scale?
I did what I was told by The Boss! It was more or less as you say, however.
FLJ
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I did what I was told by The Boss! It was more or less as you say, however.
FLJ
So the wife set the scale ??? :} :}
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No - it was John Rudd, who was one of the two partners in Model Avionics. They made the first kits at their premises in Woolwich, and then the business became Balsacraft International Ltd and moved to Watton in Norfolk. John died in 1999. His widow Tricia and her brother Ian Hull continued to run both Balsacraft and SLEC, but the inflow of cheap ARTF model aircraft killed the market for all UK kit manufacturers. The rights to the Huntsman and Perkasa boats passed to Anglian Model Supplies. SLEC still make one or two of the old aircraft kits and continue to supply balsa, ply, strip wood and plastic injection-moulded accessories.
My design work wasn't done on a royalty basis - unfortunately!
FLJ
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FLJ
Thanks for the interesting story, it's nice to know the roots of where some of our models come from. The cheap ARTF kits have not completely killed of the builders kits there are still some around and I notice that SLEC are producing some of the old Balsacraft kits and also a small boat kit called the Samurai.
What would be nice is if the Huntsman and Perkasa were produced as a CNC or laser cut kit that slots together. I've built a few aircraft kits from this method and they are so simple to build, just slot together and then squirt on the glue! They are much easier to build than a die crushed kit with parts that have to be reworked to fit.
Do you still design models?
Phil.
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Hi Perkasaman I think you need a new book as the Peter Du Cane - one is no good for the design of the hull of the Fairey Huntsman or the Swordsman (totally different rules) they are deep ‘V’ hulls and the RTTL is a flat ‘V’ hull – so different propeller shaft angles. Also there are different hull trim angles – try the book Milestones in my design by Renato sonny Levi – he designed the offshore power boat Surfury.
Aye
John e
bluebird
:-)) :-))
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Flying Spark's pics suggest FLJ' s design/plans, like many others at that time, assummed i/c power - 60?. Most modellers would have added ballast weight to help stability/steering and avoid 'skating'. Electric power is now a real option and this is a big light model.
The original' Fairey' Huntsman 28 drawings I've seen show a twin prop layout/engines situated almost mid-length, carried symmetrically 'high' to clear the deep vee/ enable substantial engine bearers. The rudders/props up on the transom edge - shafts extended to horizontalise thrust as much as possible. The deep Vee stern of this design would certainly enable better flow to the twin props. There's plenty of other relevant threads on the forum re power options/handling etc. - this is a very popular 60's offshore boat kit. 8)
I'm trying to avoid pedantics/hijacking Derek's thread %) - I'd rather try and keep the info/perspectives/observations flowing for Derek's ''blank canvas'. Stavros has shown what a single MMB 900 can do with the large Perkasa :o - I prefer twin prop/tank steering fun with long shafts and motors set as low as possible (original design) but I'd be also tempted to slap a 900 in the vee with long ballrace/high rev shaft and a 50X then pile on the voltage. %%
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also a small boat kit called the Samurai.
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And the old FLJ is to blame for that boat as well O0 O0 O0 O0 O0
john e
bluebird
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When you think about it FLJ is to blame for quite a lot. {-)
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also a small boat kit called the Samurai.
The 24" Swordsman was originally designed for Precedent but the then-owners of the company, Messrs Ripmax, thought it looked too dated. Samurai is really just a Swordsman with the corners straightened out. The name should be a giveaway!
Perkasaman is right in as much as the boats were orginally designed for IC power. In 1972 we had only just seen the arrival of the Mabuchi 540 motors for model aircraft; these were sold in the guise of the Ripmax Bullet and MFA Hummingbird. It would have been impossible to find even one electric motor with the power to shove a big Huntsman up onto the plane, while battery technology was only just then touching on using Nickel & Cadmium as an alternative to lead and sulphuric acid. The 1/8 scale Huntsman 31 used a HP61F R/C glowplug motor - the same type as 'Ramon' has fitted to his Huntsman 28 model. I left Model Avionics before the 34" model had been tested, but I gather she went like greased weasel pooh with a HP40F R/C.
I haven't designed a model since I made the orginal plank-on-frame 1/40 scale HMCC Sentinel which Model Slipway then took up as a kit, although I have a had a hand in several of Slipway's kits since then.
One day I'll re-do the Huntsman 31 in 1/12 scale for twin Speed 600s.............................one day!
FLJ
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Xmas day or boxing day then Dave ;)
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One day I'll re-do the Huntsman 31 in 1/12 scale for twin Speed 600s.............................one day!
Wow, I want one, now :-)) Do you mind if I put twin brushless in mine though :}
Samurai is really just a Swordsman with the corners straightened out. The name should be a giveaway!
Doh, it's so obvious but penny didn't drop when I looked at that kit.
Phil.
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One day I'll re-do the Huntsman 31 in 1/12 scale for twin Speed 600s.............................one day!
FLJ
Thanks for all the info, FLJ. Do you think that twin Speed 600s would get my 1:8 Huntsman up on the plane or would you recommend Speed 700s. I am trying to keep my costs down to a reasonable level and do not want ridiculously expensive motors :-)).
Derek.
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Thanks for all the info, FLJ. Do you think that twin Speed 600s would get my 1:8 Huntsman up on the plane or would you recommend Speed 700s. I am trying to keep my costs down to a reasonable level and do not want ridiculously expensive motors :-)).
Derek.
I wouldn't think that Speed 600s would do at all; they're fine for the smaller one maybe. I haven't any experience of fitting twin electric motors in one of these so I'd only be going on instinct. My own choice would be 3:1 geared 785 Darke Horse motors on 20 cells each, but that's a hefty price tag. 700BB Turbos would probably do but perhaps two MMB900 motors on 18v would be the most cost-effective place to start?
I'm open to other suggestions!
FLJ
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What are the advantages of fitting twin motors? I understand it's as the full size was powered but is it more efficient than having one big motor?
Thanks
Phil
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One of the biggest advantages of twin shafts is stability.
With 2 props in the water it gives deep stability on each side of the hull.
In a single shaft set up you can reach a point where the power lifts the hull out of the water and starts to lift the "Deep V" which reduces the force on the underside of the hull and can make the hull unstable.
Bob
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Thanks again, FLJ - all very helpful. :-)) Also many thanks to Perkasaman for his helpful PM. :-))
Phil,
I don't suppose that there are many (any) advantages using twin, as opposed to single, installation. My thoughts were (1) I wanted the installation to be similar to the full size Huntsman and (2) the twin props do not project quite so far below the lowest point of the hull as a single. I suppose it all boils down to personal preference really. :-)
Derek.
And having seen Bob's posting just before I posted this one, I would agree with what he says.
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Another big advantage of twin props is that they can be 'handed' - LH and RH and thereby avoid 'torque reaction/steering' which a high power single motor/prop layout can cause and should help 'neutralise' handling, especially at high speed. The Graupners (Speed 600/700's perform identically in either L/R direction in my experience.) Is there any advantage/disadvantages to contra spinning the twin props either 'inwards' or 'outwards'? ( My instinct chooses outwards - ?) :-)
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Thankyou for your input guys, much appreciated. I ask about twin motors as I'm toying with putting two motors in my 34" Huntsman. The present prop shaft has been fitted too far aft and I'm thinking of cutting this off and fitting two tubes in the correct postion, this might be easier moving the current tube and using a single motor. Of course the rudder tube will have to be moved and replaced with twin rudders.
Any thoughts?
Phil.
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PM sent.
FLJ
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Hi Flying Sparks, My Higgins had twin Speed 600's with single (larger) central rudder and steered great at all speeds. A single on the deep vee Huntsman will be a lot easier and very effective. The twin rudders in line of props on flat stern of Perk49 did little to improve its 'crabbing' lousy stering - but high speed 'drifting' turns were fun. O0
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Derek,
The larger Huntsman hull handles beautifully at speed, dont be worried about single screw. I ran a Graupner 700 BB turbo neodyme, but you have to up the volts to get it moving, I was using 19.2 (2 x 9.6v ) NIMH'S, glad to see you are thinking that way anyway, no memory effect, and give up the amps great, mine where 4600mah.
Direct drive, it was all getting a bit hot :embarrassed:, so fitted a 2:1 gearbox. This greatly improved run time from 15 to 30 mins of fast running, and everything was now cold (although water cooled). I was using a Ripmax seasprint esc.
I have subsequently gone brushless, tried to change to 1.5:1 ratio, but got too hot, so reverted back to 2: The chinese cheapo esc's dont like running slow, and a friend really struggled balancing them on a twin screw setup, just could not get them to come in at the same time. I am using a castle creations esc, very expensive, so this has really been a very long build saving up money! :}. I am testing at present 5 cell 5000mah lipos, still getting the best prop sorted, currently its 52.5mm "x", as seen at the end of the video (you can easily see the changes from 50mm "s" 50mm "x" 50mm racing ally prop, then the 52.5mm "x". Tried a 55mm "x2 but it went no better.
Didnt want to hijack your thread, but there is a lot of info coming over, well here is some visual evidence of this marvelous boat at speed. :-))
I must however point out, its a Veron hull , my prop is nowhere near where it is in the previos photo, I think that was set up initially for ic running, where weight displacement would be very different, with fuel tank, engine etc, Hope this helps! 6 lipo cells next!!
(http://i238.photobucket.com/albums/ff100/pmdevlin/th_Huntsmanbrushless1.jpg) (http://s238.photobucket.com/albums/ff100/pmdevlin/?action=view¤t=Huntsmanbrushless1.flv)
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Many thanks, Red181, that gives me some more to think about and the video of your boat up and running is brilliant :-)). Don't worry about 'hijacking the thread', I am only too pleased to read everything that the very helpful Mayhemmers post on here. Whereabouts in the hull did you mount your motor? I was thinking of mounting mine under the cockpit floor, where they would have been on the full size boat.
And a Happy Christmas to everyone, hope Santa brought you everything you wanted :-) ;)
Derek..
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And a Happy Christmas to everyone, hope Santa brought you everything you wanted :-) ;)
Yep - plans for a scatch built Fairey Huntsman 28, a scroll saw, and £ donations toward the build fund! Now I just need to get the 5 week old to stop crying and the 5 year old to be an extra pair of helpful hands!
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Ha Ha, no chance there Bugs, and it gets no easier :} my 20 yr old is moaning I am on the pc on Xmas day!
Derek, here is a pic of the motor mount and prop position, I am going to do a full build tghread now its finished :-))
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Bugs, I am glad to say that we are well past that stage now ok2, my xx year old daughter is here with us helping to taste the champers :-)).
Thanks for the photos Red and looking foward to your build thread. :-))
Derek.
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Hi
I built one last year with Brushless motors and it works really well. I chose 2 Graupner 750 in-line motors and got them from Gliders in Newark powered by two 14.8 volt lipos and 2 100 amp ESC's.
I thought the build was a real hassle getting the GRP hull and ply internals to fit and fitting the hatch to the deck was not easy either. It made me think that building it from scratch would have been more rewarding.
Good luck with the rest of the build. The model works really well in very choppy water and mine flies through the air just like the big ones did on a good swell.
Must go got some sprouts to peel.
Cheers
Martin
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Hi Martin,
Thanks for the input. As you have probably read, I was interested in brushless motors (and still am) but had problems with programming them. :(( Did yours run forward and reverse or foward only? {:-{ I know that there are ESC's on the market that do both, but at prices that are prohibitive to my level of the hobby. :(( My ESC's and programming card were from China/Hong Kong and were cheap enough to give up on, if necessary, but, at the same time, rather disappointing. :(( :((
Derek.
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Further to what Martin said about this boat. I would agree with him about the fit of the framework to the hull (as previously mentioned by Martin Admin). I have just started to fix mine in place and I think I will have to be very careful not to end up with a hull/deck edge that is not completely out of shape. I think that the answer would be to build from scratch from decent drawings but, unfortunately, you could never achieve satisfaction using the 'Precedent' kits without a lot of work to correct the inbuilt problems.
I wish that Anglia Model Centre would read this listing and get their act together to put out a decent kit (or pass it on to someone who was prepared to do that) as it is a smart looking boat suffering from lack of interest and development. :(( :(( :(( I don't suppose they will as they appear to be able to sell kits without a lot of input from themselves and a complaint from one individual would get nowhere - a great shame as, I think, this boat deserves better. :(( :((
Derek.
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this is a picture of two Turborix speed controllers just layed in my mini fire Tender they where a pain to set up BUT when I was at Deans marine end of year show there was a chap there with the same controllers in a BIG lifeboat with Thumper motors in he had it crawling along and then when needed he could put a spurt on but because it was a small pond (Puddle) he had it back and forward no problem docking etc he said it took him a bit of time to sort them out but he was very happy, Martin Mayhem may know if he is a member and he may be able to help, I took mine out as it was just overpowered it was turning with the deck in the water etc and every run was nearly its last. but the parts where bought 3 years ago nearly if you look at the blog on fire boat website but we know a bit more now and it has been re motored (prob still to much)
I have some vids of Paul's red181 boat when it had the 700 bb in and it went well and you got 20+ min flat out most of the time, if it was mixed running it would prob be 40 min and they where old cells Nimhs at the time.the distand to the back need to be considerd carfully as we altered Paul's to suite electric running where you can move the weight about to suite, i think Paul was going to measure the distance we settled at, Ramon had a lot of handling problems with his but his prop was much furthere back.
Peter
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Hi Derek
The ESC's are Danlions 100AMP which have reverse as well. I got them from Astec. They are programmable but work perfectly well on the standard factory settings. I built the internals and deck to fit the GRP hull so it is a bit wider than scale. There is a hollow in the moulding, port side towards the bow which I did not see until it was painted. If it's not too late have a look for it.
I have to admit I do not know how to attach photos on this forum?
Cheers
Martin
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Hi Martin,
Many thanks for your latest info. :-)) I see that you also have fitted trim tabs.
Derek.
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Hi Derek
The ESC's are Danlions 100AMP which have reverse as well. I got them from Astec. They are programmable but work perfectly well on the standard factory settings. I built the internals and deck to fit the GRP hull so it is a bit wider than scale. There is a hollow in the moulding, port side towards the bow which I did not see until it was painted. If it's not too late have a look for it.
I have to admit I do not know how to attach photos on this forum?
Cheers
Martin
Is that a Tony Abel IOM in the background? (Sorry to be nosey...)
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Hi
No it's a Lion built from a Graham Bantock plan
Cheers
Martin
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More advice, please, Mayhemmers. Do I instal the prop shafts in line with the centre of the lowest point of the 'V' of the hull or in line with the two lower spray rails? Hopefully you will be able to see from the photo that I have marked two lines each side of the hull as a guide to making the holes for the shaft and the lines following the spray rails diverge from the ones following the bottom of the 'V'. Hope this makes sense. {:-{
Derek.
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Further to the above posting. The outer lines are the proposed position for props, etc. The two inner lines were marked as a consideration but I decided that they were too low in the hull and too close together.
Derek.
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The cross markings on the fore and aft lines are my proposed positions for the rudders/water scoops/props. These are (from the transom) - Rudder shafts - 30mm, water scoops - 45mm, prop bosses - 55mm. I think I am happy with these measurements it is just the fore and aft line-up I want to make absolutely sure of before drilling holes. The prop shafts will go through tubes that will be only just protruding from the hull and the after end of the shafts will be supported by 'P' brackets.
Derek.
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I think you may find the props are a bit far back and spacing a bit close but I know pictures from that angle may not show the true distance. and if you look at the build from Ramon he had a lot of problems with handling with them so far back, anyway I have enclosed 3 pictures that may help you make neat holes in the right place first time and you can also include the rudder and pickup and test for things like being able to remove prop and if you make it long enough you can check to see if you have clearance for your motor and mount then lay it on the Hull and get things spot on with nice tight holes.Just a thought
peter
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Hi there Derek
A rough guide to the centre of the props. If you take the distance from the centre of your keel to your chine spray rail - divide this distance in half. This should give you the rough centre for your prop shaft. The measurement is of course made at the stern of the hull (the widest part) - for arguments sake, say, the distance between the centre of your keel and the chine spray rail is 100 mm - so therefore the centre is 50 mm - and this 50 mm centre is parallel to the centre of your keel for the length of your hull.
To get the angles of the prop shafts it would be handy if you had a plan which shows the side profile and then you could calculate from the plan, the angle of the prop shafts.
If you are going to fit a 'P' bracket to support your prop tube as HS93 has shown in his photographs, it is adviseable to cut the slots for your tube slightly larger in the hull, thus allowing for slight adjustment.
If you have a look at the Type 42 build in warships - you will see where I have used a jig to maintain the centre of the props. What is not shown is that there is a similar jig on the inside of the hull; to support the inner board prop tubes.
The other thing is, you can make a little jig up for the angle of the prop tubes, similar to what I did on the Fairey Swordsman build - that is in the Masterclass/plans for the beginner on this forum. You will see how I made a temporary jig up out of a piece of plywood; and then tacked it with superglue to the proptube.
aye
johne
bluebird
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Many thanks, Peter and John. That has certainly given me some ideas to work on. ;) :-)) So far as positioning of the prop in relation to the stern is concerned, I was working on a photo that I have of the full size Huntsman combined with a little 'guestimation'. :-)
Every little helps. ok2
Derek.
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Hi Derek,
mine is :
Distance from end of hull to rudder post centre = 50mm
Distance from end of hull to water pick up = 75mm
Distance from end of hull to end of propshaft = 110mm
These where all original Veron settings, the distance from Hull to shaft centre at tip, to create angle is 23mm, this was reduced from original IC setup to lower cog, minimise distance between prop blade tip and hull, so boat goes straight, and not try and go up! if you know what I mean
The boat turns nice, it "cuts"the water instead of skating over it, and planes just right (so far!). Ramon got to this point, then didnt do anymore, pity as his build was superb, but I personally think his handling problems where due to the prop being too far back, tool far forward and it might not plane, hope this helps :-))
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Hi Derek the picture with the supports is just to show you how you can get the position right without making holes whatever p bracket you use you can do it this way just a bit of card plasticard of ply will do if you do make this type of bracket make the plate that finishes flush with the hull very thin so as not to interfear with the water flow I slotted mine so they could be slid in to position when I got the hight right from the hull, the disks with the maximum size of prop you will req are handy as its easy to suddenly find you cannot get the props of your choice on..
Peter
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Many thanks, Paul (Red181). I now wonder whether I should go along with your measurements for prop positioning, etc. :-)
Many thanks, Peter (HS93). I like your idea of a template and will probably have a go at doing something similar tomorrow. :-)
I have even risked things and drilled pilot holes on my measurements but that will be no problem if I change them as they can be filled and the underside will be the only part of the hull to be painted (I hope) to resemble the antifouling. {:-{
Once again, very useful bits of info and much appreciated. :-))
Derek.
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Pic of underside Derek, its not a very good one unfortunately :((
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Thanks, Paul. That's fine - just gives me some idea of your set-up. :-))
Derek.
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Aligning/installing the motor/shafts/rudders etc. is by far the most fiddly, frustrating ‘fun‘ <:(. It’s a pain with a ready made wobbly grp hull and you have precut internal frame structure to modify - it’s much easier when you scratch build the hull from a plan - you can decide/pencil in alignment on the side elevation of the plan and extrapolate on the relevant structure/frames - all/every measurements to hand. :-)
I'm assuming you have chosen motors/mounts and prop size (allowing extra clearance for fitting bigger props?) I used long dowel rod as substitute and splinted it ,including the coupling, onto the mounted motor(s) - I used sleeving/matchsticks/electrical tape - straight n' true. I then decided on my parallel (or splay) dimension and made a couple of temporary symmetrical frames/formers profiled to mount a) one for under the stern b) one for in the hull - both centred on the corresponding hull marks. (I cut these aligning frames out of thick cardboard, notched to locate/ensure parallel or splay of the shafts and maintain their equal symmetry/positioning. I used cellotape for temporary fixing - the cut and fit of the formers proceeds until the alignment/clearance of the assemplies suits/meets all criteria. Cutting/elongating slots through the hull for the shafts needs care and the rear of the boat's cradle may need to be modified to accomodate the protruding shafts.
It’s much easier to strap/support the bare wobbly hull into the cradle minus the internal framing and align the motor shaft assembly first - then cut n’fit the modified internal structure later. Offset rudders allow shafts/props to be removed easily and enable easier/more effective positioning of cooling venturi pickup fittings if needed. I found that the last measurement I obtained was the actual length of the propshaft - either choose nearest size/tweak installation or cut n’ file a pair.
I ‘resinned’ baseplate(s) on hull bottom and countersunk vertical mounting bolts for fixing engine mounts then shimmed each corner of the mounts with various washers to ensure straigt n' true alignment with released couplings.
Apologies if I’m droning on to the initiated but none of the above was obvious to me - I ended up with a hull like swiss cheese :embarrassed:- I can look back and laugh now :} - Less pain more gain! O0
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Perhaps if you used/employed one word instead/in place of two all the time your posting/reply would be easier to read/understand Mr Perkasaman. ok2
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Hi ya there Derek
I have just done a web-search for the Huntsman and these are some of the photograph I have found showing the prop positions - of the fullsized Huntsman.
It does look as though the prop shaft line is slightly closer to the keel; but, I do hope these are of some help.
aye
john e
bluebird
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Hi John,
Many thanks for the photos - I did not manage to find those when I was Googling. I think that I am happy with my 'guestimation' for positioning although the set-up for my props, etc., will be slightly further apart than on the full size.
Derek.
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Is it me, but it looks like both props are going anti clockwise ? I thought they would counter rotate.
How will you be doing yours Derek ?
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Hi Phil,
Couldn't really see from the photos what 'handed' the props were. I intend fitting a right handed prop to the starboard shaft and left handed to t'other.
Derek.
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Bluebird, on those pictures of the Huntsman that you posted do you know what the extension below the stern tube brackets are for?
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Hi there Flying Sparks
The extensions on the bottom of the ‘P’ brackets are rope cutters. These are there to try and prevent the propellers from being fouled and also to give some protection against the tips of the blades on grounding.
Aye
John e
Bluebird
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Divvent fret wor Dicky - jus reed slowa man! :} O0
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Great pics Bluebird, those extensions on the bottom, bet they would have helped Ramon with his handling problems?
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Is it me, but it looks like both props are going anti clockwise ? I thought they would counter rotate.
How will you be doing yours Derek ?
You're right Phil, both props are the same hand. :-))
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Divvent fret wor Dicky - jus reed slowa man! :} O0
Sorry, cant read that slow I have a life to be getting on with.
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Hi there
One of the reasons that both the props are left-handed is the space available inboard. The gearboxes on the end of the motor face towards the stern. To incorporate a reversed gearing into one of the gear boxes - you would have to slightly increase the length of the gearbox and therefore shortening the propshaft. Or, do what they do on the military vessels and use a reverse 'V' drive - where the engines are literally mounted over the top of the prop shafts drive through a 'V' drive gear box which incorporates a reversing gear for one of the engines. Now, one of the other reasons through tests carried out, it has been proven that both props turning the same way produces a slightly faster boat.
The other thing is of course, cost. Reverse drive gear boxes are pretty expensive in the 'real I am world' some of them may cost as much as the main motor themselves.
aye
john
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The extensions on the bottom of the ‘P’ brackets are rope cutters. These are there to try and prevent the propellers from being fouled and also to give some protection against the tips of the blades on grounding.
Hi Bluebird
Aha. Thanks for your reply, obvious really, except for people like me.
Phil.
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A semi bare shaft + bushed 'p' bracket setup will certainly have the scale look but an ultra/zultra high rev engine (brushless or 700 BB) installation may wear out the unlubricated 'p' bracket/shaft very quickly. The much (50%?) slower 12 pole 900 (MMB/BB's) on big prop(s) may be an alternative and avoid/reduce this wear n' tear and give sparkling performance and increase serviceability. The model single bush bracket is cooled by waterflow but friction/vibration may be a real issue with an ultra hi rev scale setup. :-)
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{:-{
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The model single bush bracket is cooled by waterflow but friction/vibration may be a real issue with an ultra hi rev scale setup.
Many thanks. This is something I have thought about and am considering. O0
Derek. :police:
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Hi ya there Derek
I wouldn't concern yourself too much about vibrations on an open shaft. The distance between your tube and the 'P' bracket will be no more than 75mm on a 4mm shaft. Even running on a standard prop tube without any open shaft, you still have the same length of shaft. With an open shaft though, you have the added bonus of there being a 3rd support bearing. I am including 2 photographs....of an M.T.B.... it has 3 shafts, runs 3 MTronek motors, and these motors run between 16,000 rpm and 20,000 rpm. This boat will whitewash many a /Perkassa/aye/ :o :o %)/ :-))/ {-)/ :}
aye john e/blue/bird
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Perks were almost 20 knots faster.... ;D ;) (Happy New Year to ALL! :})
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{-) {-) {-) {-)///// {-) {-) {-) {-) {-) {-) {-) {-) {-)/////////////// :-X
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Many thanks, John. I have already got one prop and shaft from Sitek, to help with setting up and intend getting the rest from him (including 'P' brackets) as he makes them as required and, I think, his prices and workmanship are pretty good. :-))
Just as an aside, I believe that the bearings in full size 'P' brackets were rubber with channels cut in them to allow water to flow through to lubricate.
Derek. :police:
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Perks were almost 20 knots faster.... ;D ;) (Happy New Year to ALL! :})
Faster than what ? {:-{
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Ok Dicky Marra, here's one clue.......................... 488 8) ( my favourite type of that period) Further clues in 2010 if sober enough. ok2
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Derek
Any news on your Huntsman?
I've had some progress on mine now, could be running in a couple of weeks. Will have to wait for warmer weather until I do the finishing and detailing, too cold at present for spraying paint outside. Do you mind if I post some updates on your Huntsman thread, don't want to hijack it.
Phil.
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Hi Phil,
My Huntsman has progressed very slightly but due to the cold :(( and trying to work on my Cygnus 33 I have not got very far but will post a couple of pics soon. :-))
I will be more than pleased to see some of your pics and updates on here and I am sure other Mayhemmers will also - it all helps to keep the thread going. :-)
Derek.
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My Huntsman will be ready for a run this weekend, just need to fasten down the superstructure I don't want it flying off! The prop tube has been replaced and fitted at a sensible angle.A bracket has been made up to mount the motor, and the motor fitted. Will post some piccys soon. The paintwork will have to wait for the warmer weather so it still looks a bit rough.
Does anybody know where a Huntsman should balance? I've left space so that the battery can be moved around and changed for different sizes. When I work out which pack I will use I can make up a box to hold it in place.
Phil.
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Well done, Phil. I think that the balance point should be about midships as the boat should run almost level (or very slightly bows up) when planing but the final level can only be gained by experimenting 'on the water'.
Derek.
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there are so many variables have long battery leads and if using more than one be able to move them about, forget static see how it runs and play with weight moving don't add extra weight it just looses you speed and a Huntsman has to be fast, don't feel dispondant if it is not as fast as you hoped it may just need a prop change.
Peter
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Thanks for your input guys. When I was given the model it had a couple of pounds of lead in the stern and the first thing I did was rip this out. I would rather use more batteries than lead, at least then any extra wight is earning its keep. With the battery pack in the centre of the hull it balance just about aft of the centre so I guess this should be a good starting point. Also I have several props to try and I will plug in my data logger to see how much current the motor is drawing.
Phil.
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we used data logging and gps testing pauls two boats red181 , plus where fortunat to have a few Props to try these are some of them.
Peter
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The 'Rainhill Trials' .......... was there a 'Rocket' amongst them in the case? They look fairly large -- I'm researching for a pair of 50/52.5 mm dia. handed props and a lot of them look pretty close to those sizes. :-)
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no that was down the road, yes there a a few around that size some smaller some larger the thinking is low a low KV and big steam prop or similar we found a clever worked well with both geared 700s and Brushelss.
peter
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Peter
WOW, thats quite a collection of props there!!! :-)) I will have to do with a few plastic one for now. I haven't got a GPS (yet) for my logger but I have got amps, volts and temperature, enough to make sure I don't wreck anything.
Phil
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I know every set up is different, but the 52.5mm "x2 prop seems to win all the time, with amp draw speed and acceleration on my boat. 55mm things get too hot, and its no faster, 50mm and under a noticable drop in speed, testing is the only real test! :-))
Good luck, keep us posted :-)
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the best way is to start small and work up, you can see if the temp start rising, if you go big straight away you can have a barbecue before you start.. {-) {-)
peter :o
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well............................................there is a tale to HS93's post, might aswell share it for a laugh. Few months ago I was testing my floating gym palace, the Huntsman, decided, as it was very cold, and rain threatening, to just go straight for the biggest prop that would fit, for approx 5 seconds the boat was so fast I was petrified, then I finally achieved that ellusive very black smoke that all smoke units cannot deliver, very impressive. Ubec literally blew up, the capacitor left the boat at a fast speed, one of the lipos died, and the esc fried (very impressively)Thats what you get for not being careful <:(
I remember the day well, sept 29th, my birthday! >:-o HS93 p***ed himself laughing! and will not let me forget it. Lot to be said for testing in private :embarrassed: on your own.....................................
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don't forget the BEC when we opened the cabin %% %% :(( {:-{ Oh and who said go smaller first and keep bringing it in :-X
Peter
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Few months ago I was testing my floating gym palace, the Huntsman, decided, as it was very cold, and rain threatening, to just go straight for the biggest prop that would fit, for approx 5 seconds the boat was so fast I was petrified, then I finally achieved that elusive very black smoke that all smoke units cannot deliver, very impressive. Ubec literally blew up, the capacitor left the boat at a fast speed, one of the lipos died, and the esc fried (very impressively)Thats what you get for not being careful
Thanks for sharing your story Red :embarrassed: I will try not do do the same :-))
Do you know that the smoke that eminates from electronics is magic smoke. Magic smoke makes electronics work. If you let out the magic smoke it no longer works, as you found out %%
Phil.
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we had that much a guy at the other side of the lake thought we had a new pope. %%
http://www.orangecone.com/archives/2006/12/magic_smoke.html
I sent Paul the tune Smoke on the water he was not amused as it was properly not far off £200 pounds went up be we think we found the problem out. which at least we know now what to look for, it happend so quick.
peter
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My Precedent Huntsman had her first test runs today :} :} :} :} Great fun. Todays runs were using a 2 bladed 45mm prop, it was too cold to try anymore. The first run was with a 8 cell Nimi, run OK but not up onto the plane. Second run was with a 3 cell Lipo, better just getting up onto the plane. The next run was with 4 cell Lipo, now we are getting some where, not blisteringly fast but a nice fast, scale like run. I attached my Eagle Tree data logger for these runs and a great supprise that on 4 cells I was only pulling a maximum of 18A. The speed controller is capeable of 60A cont and the motor about 45A cont and the batter pack about about 70A. So I'm well within the limits and nothing was even getting warm.
However I do have a handling problem that needs to be fixed before I try to tune for any more speed. When making a turn at speed to left or right and I give a bit too much rudder the hull rolls right over and if I don't back off it looks like she will roll upside down. The general feeling is that the rudder needs trimming down. Also I thought I might try mixing the rudder to the throttle channel and reduce the rudder throw at higher speeds. Any thoughts on this one?
Any how it looks very promising and was great fun. When I've got the handling sorted out and the weather is warmer I will strip her down for a repaint.
Phil.
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Rudder should only turn about 35 degrees or it acts as a brake :-)).
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Hi DickyD
Not sure of the rudder angle, I will check it tommorow. The problem was not loosing speed though, it was the hull rolling into the turn that concerns me :o
Phil
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phil, strange handling problem with that hull, is the cog high? what mah lipos where you using, where have you got them mounted?
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Deep Vees do roll in turns - it's the nature of the beast. 30 degrees is more than enough rudder throw - or simply don't push the stick so far over at speed (that's why we have proportional radios 8))
FLJ
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Hi Guys
Thanks for your replys, Iv'e at last managed to get back out to the boatyard (garage) to have another look at my Huntsman. The rudder throw is 30 degrees either way. The Lipos are on the hull bottom next to the keel and the motor is mounted quite low. I'm going to trim a bit off the rudder as it looks a bit long, not sure how much though.
It's interesting to learn that deep Vs roll into turns though. I can drive the boat using the rudder so that it does not roll too much but I would like to prevent it rolling right over if possible.
Phil.
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have you got a picture of the rudder servo linkage, it may just be that and we can offer a way of sorting it, I had the same with a fire boat , it was OK out of the water but water pressure took it further than it locked.
Peter
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Peter
I can post a photo of the rudder later, I'm a work at the moment :(( I don't think it's locking over though, as soon as I ease off the rudder the roll stops. Another change I going to make is the receiver. At the moment I'm using a simple 27MHz 2 channel. I will swap this for a 2.4GHz Spektrum receiver. With this I can program in either some exponential or mix the throttle channel to the rudder so that at higher throttle settings the rudder moves less. Or I could simply set a dual rate for rudder, using more movement for lower speeds. I think the mix would be best option but it will take a bit more effort to set up.
Phil
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Phil I dont think that you should have to go to all that trouble to sort the rolls out, something must be fundamentally wrong, have you looked at the last part of the video in my Huntsman build thread? There are some quite tight fast turns there, it does roll, but is really quite flat and handles real nice in turns, is your "roll" much more than in the video?
It might be the position of the rudder, rather than the size. I had a similar problem on another fast boat, rudder when too big was acting like a brake, and causing the bow to submarine. When Ramon was building his Huntsman, right to the point of testing, he had a similar problem with rolling, when he posted pics of the rudder it was right at the back of the hull. This could have been his problem as the boat was almost "hinging" on the rudder, if you know what I mean!. Where is the rudder positioned, try and load a photo for us to see :-))
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Red, I've had a look back at your video, my Huntsmans rolls more than that. She goes to quite a scary angle. If you look back in this thread to the photo's that I posted you can see the position of the rudder tube. I will take some photo's to show the size of the rudder. The rudder is the one that came with the boat and not sure if it's the correct one, maybe it's too big.
Another thought, earlier in this thread Bluebird posted some pictures of a full size Huntsman showing a dagger shaped extension below the P tube, I wonder if one of these would help. I will fit one anyhow it looks good.
Many thanks
Phil.
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Another thought on the rolling issue of my Huntsman: The full size has twin shafts, is this more suitable for this type of hull? Although looking at the photo's that Bluebird posted it looks like the full size props both rotate the same way, would this make the handling potentially worse {:-{
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(http://s4.postimage.org/atjp9.jpg) (http://www.postimage.org/image.php?v=aVatjp9)
Photo attached of the rudder on my Huntsman. I was just about to hack a lump off the bottom of the rudder then I had a brainwave, my SHG Shadow has the same size rudder shaft but the blade is smaller so I have put the Shadow rudder on for a try. If this gives me less rock and roll I will cut down the nice shiny brass rudder and refit.
Phil.
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Hi Phil, been thinking about your prob, although mine is built from different plans (Veron) the principle handling should be very similar. I am certainly no expert, particularly in the company of this forum, but by process of elimination,
COG ok
Rudder looks same as mine
waterline down is same as mine
big difference is the position of prop and rudder. On Veron plans prop and rudder is closer to transom, and this could be the problem, we spent a while changing the angle of the prop so the prop blade was close to the hull, and close to the rudder, which is much farther back than yours, unfortunately moving it is a big job, but if you look at Bluebirds pic earlier of the MTB its almost identical to the position on a full size Hunts.
I was out testing today, but the lake was just too small, and there was ice one end, but I was monitoring the roll in fast turns, and once it gets to a 2/3rd point on the hull it goes no further, keep us posted of your progress, pic of a real Hunts, and pic of my prop/rudder position, end of pic is end of hull
sorry Derek, your thread has really been hijacked, perhaps Moderators could split it?
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Hi FS,........As always %) there are many pro's and con's for either single / double shafts and or rudders, but I'm thinking that the placement of 2 lbs of lead (initially removed) in the bottom of the stern may also have had an important role in the stability of the hull and also helped it to resist excessive rolling?
Shortening the length of rudder plus moving it's con-rod to clip closer to the servo pivot on the horn may help steering. Both strategies will reduce the rate of turn/effectiveness of the rudder............ cautious tweaking/adjustment of steering characteristics may keep the adding of any additional lead ballast weight to a minimum. Although this fast deep vee hull is problematic, the advantages..............increased speed/comfort it gave in offshore racing in difficult/variable wave conditions more than compensated. These vee hulls need some weight for stability.......... The closer the running gear is to the keel bottom the better, for optimum stability and resistance to rolling on turns. Tweaking the location of the batteries is easier with Nimh sets and initially every possible placement should be thoroughly explored.
Credit to FLJ, designer of the Huntsman kit for moderating the very deep vee of the original design to substantially reduce the liabilities for modellers of this offshore evergreen.
Enjoy the challenge these early racers faced.......... tweaking/honing the trim/handling... It can be a large chunk of the model boat fun, for many, including me. %)
Before the advent of modern power adjustable tilt/ plates/tabs etc the challenge for these guys was to find an optimum set up for their boats for max speed in most sea conditions......... it was'nt a millpond very often. One winning boat had her rudder and prop behind the stern so I would'nt worry too much about relocating the rudder. :}
The modern RNLI designs although slower, provide excellent examples of ultra stable deep vee hulls which successfully 'tick the boxes' for handling , stability and optimum speed offshore. :} Apologies for the long post I hope some of it is useful.
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Red and Perkyman, thank you for your help, much appreciated. It is possible to move the rudder back by about an inch. If you are familiar with the Precedent hull it has bulkhead just behind the rudder and before the transom, it would be major work to move the rudder to the rear of the bulkhead. The position of the prop is from the figures that FLJ gave me 145mm from transom. I could move the battery pack further back and use two 8 cell NiMhi pack instead of a 4 cell Lipo. I notice on the photo that Red posted that the full size hull ans an extension behind it, I wonder what that is for?
Derek, sorry to hijack your thread. How's your Huntsman doing?
Phil.
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Hi Guys,
I am not in the least bit worried about you 'hijacking' the thread - I don't think you are and, in any case (as they say) every little helps. :-))
I'm afraid that my Huntsman has not progressed very far at the moment but will post some pics (hopefully) in the not too distant future. :((
Keep up the good work, chaps - I am enjoying evry bit of it. :-) :-))
Derek.
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Hi Phil, The original kit plan gave appropriate layout/build instructions suitable for a single very light/powerful i.c. engine installation efficiently located well forward in the hull ........however,using this layout/location for a much heavier electric motor will affect handling/stability issues. As the speed increases the bow is rising to plane and raising this much heavier weight on the running 'knife edge' of the vee. It's understandable that the stern was heavily weighted to stabilise the hull..... especially, in sharp/abrupt turns at high speed to minimise rolling. Perhaps Fitting/swopping in a frantic/featherweight brushless motor may enable you to 'sweep away' most issues and achieve the much higher performance of FLJ's original swift lightweight design without altering layout or adding extra weight. Your small prop is a plus - high revs/well submerged/low drag, and avoids the weight and potential issues of shallower rear twin prop layouts. Trim adjustments with battery placement is also far easier and less obstructed with the forward engine placement. Going single brushless could put a big smile on your face and save a lot of additional work......... Ideas/food for thought. :-)
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all the running gear needs moving back 2" you don't want extra weight and a good brusless plus batteries is heavier than an IC motor and fuel etc, reds huntsman has a gear box that adds a bit more weight although it is a lot lighter than it looks, all the main weight is in the rear 50% of the hull in the front cabin is a receiver and batteries only, you do not want to put extra weight in it just kills speed especially with electric, we had to move the shaft back on red181s and reduce the angle that is why the underside near the prop still looks a bit tat as we wanted to be happy we had it right, the veron boat started with the shaft further back than yours more like the original boats but only a single, you need to have as much weight as low as possible, the rudder should not be a problem at that size, on the last boat we played with a fire tender chopping the rudder transformed the turning , but this is a different shaped hull and needs it for slower running.
Peter
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single very light/powerful i.c. engine installation efficiently located well forward in the hull ........however,using this layout/location for a much heavier electric motor will affect handling/stability issues
I am using a brushless motor that is in roughly the same position as a ic engine. My motor weighs less than an ic engine and also I used 4 cell Lipo that weighs about the same as tank of fuel. Speed is not an issue, I have plenty of that, and I believe there is much more to come when I try different props. First I want to iron out the excessive rolling. This weekend I'm going to try a smaller rudder and moving the battery pack further back.
Thanks guys :-))
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I managed to get another test run in today. I put a smaller rudder on and the rolling is defiantly less twitchy, still rolls but not as sensitive. So now I will cut down the original rudder and refit. Another change is I've switched this model to 2.4 radio, won't make any difference to the handling but I want to try mixing the throttle channel into rudder to give less throw at higher power settings. I changed the prop to a X45, more speed and now pulling 22 amps, still well inside the limits and the motor/esc/battery barely gets warm. I don't think it needs to go any faster she is planing right out of the water now, looks great. Also I will try a little weight at rear.
Will post some piccys soon.
Phil.
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This is as far as my Huntsman has progressed to date (not very far but we are getting there, slowly). The framework is installed into the hull using P40 and the rudders are temporarily installed. I think that the next step will be cut the slot in the hull for the shafts and set them up along with the motors. Think I will try BB700 Turbos to start with and then if they don't have enough 'get up and go' I will try brushless.
Derek.
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Hi Derek
Nice to see some progress on your Huntsman, looking good :-))
Just an idle thought, has there ever been a Huntsman gathering as there must be quite a few models around :}
Phil.
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Thanks, Phil. It would be interesting to see a Huntsman gathering, or should that be a 'meet' in hunting terms. O0
Derek.
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It would be interesting to see a Huntsman gathering, or should that be a 'meet' in hunting terms.
{-) {-)
Phil.
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I'd appreciate an invitation if this ever happens.
FLJ
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well there is an annual model fireboat convention, so why not Huntsman, there are a few variations kicking about, it would be great to get all sizes and shapes together, so how about it FLJ, you could be the president (precedent)of the Huntsman gathering !! ;D
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Nice idea, but there's the small matter of trying to keep pace with customers' demands for our gizmos. 24/7 was always an exaggeration, but reckon it must be 10/6 at the very least - even in a slack week! Can't remember the last one of those, either.
I used to have a hobby................... :((
FLJ
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I used to have a hobby...................
Classic mistake of making what you enjoy into your occupation....hobbies are for enjoyment, work is for money to enjoy the hobbies.
I've come to dislike my job after all these years <:(- but it pays the bills :-))
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The full size boats really did bank into corners. That was the word they used, probably through the company's aeronautical connection and the fact that Peter Twiss was the test driver.
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I want to achieve this with my boat! :}
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I want to achieve this with my boat!
Mine did that!
Phil.
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Hi Mayhemmers,
Sorry to say that I lost heart with my Huntsman and sold it on to another club member. He completed it and, although I never saw it, he said that it would not get up and plane with the 2 outrunners I had fitted. Having thought about it and learned a bit more about brushless motors, he was probably not using enough volts. I just lost heart with the Huntsman because every stage of it revealed more and more problems and when I have finished a boat I like it to look good but I thought I would never have the patience to achieve it with this one. :((
I am now moving on to a 46" RAF Crash Tender - Kingston Mouldings grp hull and fittings, etc, etc., from Vintage Model Works. They do timber kits of the 34" and 46" Crash Tenders but I fancy the GRP hull. :-) :-))
Derek.
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I have built a twin screw 34" model from kingston if the bigger hull is as nice as the small one you will have a nice boat build it light if you can .
Peter
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Hi Derek, great to hear from you again, good luck with the Vosper. Let us know how it goes. ok2