Model Boat Mayhem
The Shipyard ( Dry Dock ): Builds & Questions => Pleasure boats, Sports, Race, Power and Leisure Boats: => Topic started by: Jon on May 23, 2011, 03:35:42 pm
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I’ve acquired a boat off a good friend, that needs some work doing on it. It's a cabin cruiser of unknown age or design (maybe someone can help there).
I’ve already started work on it, but thought I'd go back a couple of weeks and start a blog.
When I got the boat it was in a fairly poor state, with splits along the length of the hull (plank on frame) and deck, I suspect most of these had been caused by the addition of 'Flotation' foam in the bow, the expanding foam doing what it does best and expanding! Most of the fittings were broken the whole thing needing a complete overhaul.
(http://s2.postimage.org/13ro81484/DSC03378.jpg) (http://postimage.org/image/13ro81484/)
(http://s2.postimage.org/13rrj3t7o/DSC03381.jpg) (http://postimage.org/image/13rrj3t7o/)
(http://s2.postimage.org/13s33v8o4/DSC03382.jpg) (http://postimage.org/image/13s33v8o4/)
The running gear was a 4ch Ripmax receiver, running directly (NO BEC) off the main battery pack which was five 2V Cyclon lead acid cells (10V nominal), the receiver still working, had suffered from some overheating and melted the case.
The motor was a 6V Marx Hectoperm (IIRC these are ~3K RPM at 6V) so this was running at about 5000 rpm off 10V. The speed control was a custom made, cam/gear/switch/resistor/transistor setup, absolute work of art, but I'm NOT keeping it!
This is driving a 4BA shaft with a 2" 3 blade prop on the back.
(http://s2.postimage.org/13s4rel5w/DSC03383.jpg) (http://postimage.org/image/13s4rel5w/)
(http://s2.postimage.org/13s6exxno/DSC03384.jpg) (http://postimage.org/image/13s6exxno/)
(http://s2.postimage.org/13s82ha5g/DSC03385.jpg) (http://postimage.org/image/13s82ha5g/)
(http://s2.postimage.org/13s9q0mn8/DSC03387.jpg) (http://postimage.org/image/13s9q0mn8/)
So far Ive stripped the hul, filled it, sanded it back, 2 coats of primer, them four light top coats. Painted the waterline, stripped and rebuilt the hecoperm (although I'm looking at replacing this), and added new supports inside.
(http://s2.postimage.org/14l4bikro/DSC03396.jpg) (http://postimage.org/image/14l4bikro/)
(http://s2.postimage.org/14l5z1x9g/DSC03400.jpg) (http://postimage.org/image/14l5z1x9g/)
(http://s2.postimage.org/14laxnyqs/DSC03404.jpg) (http://postimage.org/image/14laxnyqs/)
(http://s2.postimage.org/14lcl7b8k/DSC03456.jpg) (http://postimage.org/image/14lcl7b8k/)
(http://s2.postimage.org/14lhjtcpw/DSC03500.jpg) (http://postimage.org/image/14lhjtcpw/)
(http://s2.postimage.org/14lj7cp7o/DSC03506.jpg) (http://postimage.org/image/14lj7cp7o/)
More to come shortly......
Jon
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The boat is almost certainly a Tarpon design which is still in the MyHobbyStore plans range: http://www.myhobbystore.co.uk/search.asp?k=tarpon&= It is apparently a scale model of an Italian design built by Vosper and judging by the plan number dates back to the late 1950s/early 1960s.
Colin
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Thank-you Colin,
I hadn't even given the boats name a thought. Should have Goggled Tarpon for a start really, but thought it was just a name that had been put on.
Thanks for the link as well, I'll have to see if I can find some more photos on the web to help finish her off.
Thanks again.
Jon
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Right, things have been a little slow recently, but I've managed to get some more work done on the Tarpon.
I've re lacquered the original handmade copper port holes and fitted them back in, they seem to be 12mm copper pipe with a washer of copper soldered to it, then blanked off with P38, inside painted black. I quite like the concept, so I decided to re use them, rather than getting some pre made replacements.
(http://s1.postimage.org/fau9fais/DSC03520.jpg) (http://postimage.org/image/fau9fais/)
The rudder is now in with a micro servo from Hobby King (HK 15168), seems to have ample power, and was easier to fit as it was just the right height for the rudder arm.
(http://s1.postimage.org/fcb6mebo/DSC03517.jpg) (http://postimage.org/image/fcb6mebo/)
The motor that I'm going to use 1st off is a rewound 12V Johnson 5xx long can motor from a battery drill. It's 5 pole which is why I chose it from the pile, but it went round too fast, and drew about 4A no load at 6V
So, I’ve rewound it so it goes round at ~1000 rpm/volt, unfortunately I’ve misplaced my notes from that evening, but from memory it was about 50 turns per pole of some wire I salvaged from a TV deflection coil.
It runs at about 1A no load now and nice and slow. It's been in the bath, and doesn’t slow down too much under load, so seems to have the grunt I need. We will see when she gets in the water whether I’ve got it right or not.
The motor mount I custom made to place the motor as aligned with the prop shaft as possible, 3mm aluminium will help to cool the motor a bit.
(http://s4.postimage.org/1lvfdkpt0/DSC03516.jpg) (http://postimage.org/image/1lvfdkpt0/)
(http://s4.postimage.org/1lvlzq3s4/DSC03518.jpg) (http://postimage.org/image/1lvlzq3s4/)
So the radio shelf is fitted, with an old Traxxas XL-1 ESC, and the FS-R6B 2.4GHz receiver. I’ve disabled the BEC on the ESC so if I need to go to 12V it won’t complain.
Receiver batteries are in the foredeck hatch, and the receiver switch and blue LED indicator are on the radio shelf.
Hopefully I will get it on the water this weekend.
Batteries are the next contemplation. The 6V 10Ah lead acids I have are just a little too heavy as are the 12V 7Ah, so I have some 1200mAh NiCad’s (8.4V) and the Lithium 'LiFe' batteries (6.6V or 9.9V) so I think I'll work out what voltage the boat needs and let that decide. Just have to add a reasonable amount of ballast if I go NiCad or LiFe.
The rebuild continues.
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Nice job you've made of it.
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Thanks for the kind comment Rockets, It's getting there.
She had her first outing this weekend in the pouring rain! seemed to go well at a good scale speed when at full throttle, very very quiet which is nice.
I ended up running her on 7.4V LiPo 10aH, but I think I'll try 11.1V next time to get a bit in reserve. Nothing got hot so looks like Ive got the motor well proportioned to the prop.
I'll try to get some photos of it on the water next week when it's not pouring down!
My Flysky 2.4GHz 6Ch V2 set worked flawlessly (tested up to about 150m), I'm very impressed for $27 shipped to the UK including 1 Rx.
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I'm looking forward to how this turns out, I have a vintage cruiser that needs attention which looks similar style as yours (although hull is a deep v) be interesting to see what you have done maybe give me some ideas on things i can do to mine, when it comes to all things vintage without seeing others like them or at least seeing roughly how she looked its very hard to tell what will look good on the model.
Keep it up :-))
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OK, so I went to 3 cell LIPO (11.1) as the 2 cell was just a nice speed with nothing in reserve, the LX-1 speed control had it's BEC disabled and was rated to 10V, thought it was going to be OK, but no, they really meant 10V! after a couple of minuites, the speed control locked full astern with smoke drifting from the currently roken windows on the boat. DOH! I could slow the oat down by putting in in forward, but as far as I can see I was just shorting out the reverse, could have been prety bad, especially with a LIPO pack in!
Anyway Ive now upgraded to a Mtroniks Marine 25, which will get it's full test this weekend, should be alot etter as it's got a much higher PWM frequency and generally much more modern.
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Well Ive just had the boat on the water, with the 3 cell LiPo it draws about 9A full ahead, so thats about 110W on a fully charged pack.
Runs very well, with about 3/4 throttle.
The new Mtroniks ESC is working well with no noticeable heat, only issue I have here, and I suspect it is with my flysky 2.4GHz setup, rather than the ESC, is that the neutral position changes slightly each power-cycle; so the motor buzzes slightly when in neutral unless you reset-up the ESC. I'll try opening up the neutral window on the tx and see if that solves the issue.
I'm running a 10Ah pack, so have a good run time but the downside of this is when running at full throttle for long periods (yes I did today :D) the motor gets quite warm, after about 25mins the windings of the motor were at about 130'C case 50'C, so I think I'll add some sort of cooling to this.
I'll probably go passive first, add a fan if necessary, then water cooled if it's still getting warm, but I'd rather not drill another hole in the hull.
I have a photo from the Holtcraft web pages which was taken at the Droitwich Model Boat Club meet when the speed control went up in smoke <:(
(http://www.holtcraft.com/images/dsmbc/images/20/dsm000955.jpg)
The build progresses.
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Those older wooden designs are far more attractive than the plastic bathtubs turned out today. Lots of character.
A very nice looking model.
Colin
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Thanks again for the kind words Colin, it does look good on the water, that's for definite.
Deck and cabin in the next month or so hopefully, then she'll be near enough finished.
Jon
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Hi, well done always nice to see a model boat back on the water, very nice job.
regards Roy
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Fantastic job fella, looks amazing.
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A great find you have there; she's got very nice lines, and I like the things that you have done to her, especially eliminating the blue stripe on her bow
Bill
USA
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Those older wooden designs are far more attractive than the plastic bathtubs turned out today.
And the plans for most of them are still available.
Regards Ian.
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Not sure why I didn't spot this thread before - your model looks beautiful on the water, you've certainly made a very good job of restoring it from its previous very tatty state! Any chance of seeing some more photos of the finished model?
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Superb work, looks terrific on the water. Thanks for posting.
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Right, I'm still working on this, yes STILL!!!
I'm having motor/prop problems. I've just managed to pop my mtroniks Marine 20 (thought they were supposed to be indestructible!) and need to re look at the motor and prop size.
Would any one have any experience with non planing motor launches of this size?
Currently gone back to the 500 can size motor, but think I need a smaller prop than the 2 1/8" that I have at the moment.
Looking for suggestions on prop size, blades, pitch and RPM, so I may get this running efficiently for once.
My 700 can motor was running at about 6k RPM, with the 2 1/8" prop, and ran well, but current draw on that batteries was higher than I think it should have been (~15-18A)
When I had the 500 can in originally the prop was loading it too much and dropping the revs so the motor was getting warm, sorry HOT! (180'C on the armature!) hence me trying the 700 can.
Any comments? preferably helpful!
Thanks
Jon
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Westbourne models do a nice 555 motor, plenty of torque. I run two of these in my graupner Salina, with 35mm 3 blade props and it move s a treat. it might be just the "slight upgrade" you need.......
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I was thinking of trying a 35mm (low pitch) prop with the 500 can I have, looking at the 555 it's about 1333rpm/volt, mine is about 1000rpm/volt, so it's about similar.
So may try the prop first then go for the motor change later if it still doesn't work.
I've got a standard Traxas stock motor (27 turn) I could try too, but I think the revs will be too high on that.
I'm currently running 6.6V LiPo.
What voltage are you running the 555's on?
Regards
Jon
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If the Traxxas is an RC car motor it's likely to be too high revving, I'd pass on that one. I run a number of similar sized vintage boats on Graupner speed 600 7.2 with 35mm two blade props on 7.2 and 8.4 NiMh and it's a formula that works well for me. Don't buy one of the cheap 500s that come up on ebay for £3.95 etc. The Graupners and the 555 as mentioned earlier are good motors to start from :-))
Roger
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Thanks for that thelegos, I'll order a 35m prop and go from there.
Yes Graupner motors are worth the money, the nobrand 500's do tend to be a little shoddy.
Thanks
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Hi,
I know this is a very old post but was wondering if you have finished the Tarpon
and are able to post any more photo's of this interesting model.
Assuming you still post here?
N
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By chance I just happened to login today after going to the boat club.
I must admit Ive not managed to do much with my models for the last 18moths or so, but hopefully am back on the case now.
I do need to sort out a new power train for the tarpon, currently the motor/prop combo is just wrong; I get an acceptable speed, but I'm loading the motor too much and so heat is becoming an issue.
I think I need a larger can motor, prob a 600, but need to work out some numbers (if possible) before I buy anything.
Can anyone make any suggestions for prop/motor/voltage for a craft of this type.
I'll get some measurements/weights to help soon.
Rgds
Jon
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That's fortunate to see my post after so long - good!
I have a Tarpon tucked away in my loft - been there for a couple years now waiting to be
worked on that's how I became interested in your post and pictures.
At a length of around 36" I believe.
I would expect to use a 600 - 700 motor on this model, as I do on most boats of that size.
8.4 or 9.6volt Nimh. With rpm at between 12000 & 15000 as a guide.
The propeller size is the fussy bit.
Big doesn't always mean faster, but can mean the motor gets pretty hot shifting too much
water.
I find that around a 40mm size, 2 blade prop moves the boat well.
You could even consider, or better still try a 3 blade.
Mtronkis Vision motors are one suggested make as Graupner motors not easy to obtain
now.
I shall look out for more photo's if you recommence working on her.
Regards
Nordlys.
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Yes quite spooky, but nice to have the reply.
The boat originally had a direct drive (not using the gearbox) 6V hectoperm driving a 2" 3 blade brass prop.
But the 6V motor was being driven at 9V IIRC and I never had it in the water like that as after I acquired it, I gutted it to start the restoration.
Thinking a hectoperm was not the best solution I started looking at alternatives.
I need to remake the propshaft as it's slightly bent causing vibration, and I'd like to use the original prop.
So I just need to get a decent enough motor for it.
Battery technology is not an issue, I can do any voltage or any type. I work with lithium batteries as part of my job and design power electronics.
I have a V.High quality large motor which I was looking at fitting, but i's 48V so I was looking for a more standard solution really.
Jon
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OK, Ive pulled the prop out and found the top bearing was worn, rather than the shaft bent.
So I've made a new brass adapter with a bronze insert, feels much better now.
I'm going to try the original prop again with the original Hectoperm, this time coupled with an Mtronics Marine20 ESC and 7.2V racepack.
Atleast it will give me a reference for RPM and power requirements if nothing else.
I've also just won a new Marx GT300/10 on eBay for £2.20, originally thinking about fitting to the Tarpon, but the more I think, the more I come to the conclusion it's OTT. The GT300/10 is a 19.2V 14K RPM 300W motor, I think I'd better think of a more suitable project for that unless people think it's a go-er in the Tarpon, maybe just under-running it.
Jon
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I've done a little more to the tarpon tonight, Removed the deck fittings and hand rails, and sanded the deck down.
Also looking at the winch on the front, with no bow fairlead or roller didnt seem quite right.
I was thinking of putting on a fairlead on the bow, and mounting an anchor to complete the set.
The boat had large bow light when it came to me, but technically this is incorrect as the nav lights are on the cabin roof so wouldnt need more on the bow.
There was no mast light and no stern light, so may have to correct this.
(https://dl.dropboxusercontent.com/u/5915667/Model%20Photos/WP_000013.jpg)
This is the cleaned up winch (less baseplate), and the original bow light that I'm thinking of changing to a bow roller & anchor.
(https://dl.dropboxusercontent.com/u/5915667/Model%20Photos/WP_000016.jpg)
Also a photo showing the now reinstated Hectoperm, and the new top bearing on the propshaft.
(https://dl.dropboxusercontent.com/u/5915667/Model%20Photos/WP_000014.jpg)
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If I can give you one very big piece of advise then it would be this......
redo the motor mount t get that coupling straight......reason being is as follows.....
A straight coupling will cause less drag on the motor and has a knock on effect of using less amps which will have an added bonus of a longer running time.
In your case it is a simple fix of packing up the rear of the motor..... hope this is of help
Dave
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Stavros....... "In your case it is a simple fix of packing up the rear of the motor".... {-) may be OK if the vessel was upside down or in the Southern hemisphere!............. Derek
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Yes, with space like you have available it would be a good idea to straighten up that coupling as Dave says, however I have to say that I see this Decaperm motor as being way too heavy
for the boat in my view and having used Decaperms on one or two boats I suspect that
being a relatively low revving motor your boat may not move that well?
Just a thought.....
N
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Yes I would agree with Stavros there, I always line up motor and shaft as straight as I can so the coupling has little or no work to do, it results in less load on the motor and less vibration, On my 3 foot timber scratch built pilot boat I used a 600 motor and a 2 to 1 reduction belt drive which works very well, originally got quite warm after some fast runs, but cutting three vents in the cabin front and sides with some mesh in them seems to have cured that , You have a beautiful boat there and I like what you have done with her, be nice to see her finished. Joe
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Hope you don't mind me posting just a couple of pictures
of my Tarpon for your interest - with a motor I had in mind to use.
N
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one other pic I missed in case you are interested
N
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If I can give you one very big piece of advise then it would be this......
redo the motor mount t get that coupling straight......reason being is as follows.....
A straight coupling will cause less drag on the motor and has a knock on effect of using less amps which will have an added bonus of a longer running time.
In your case it is a simple fix of packing up the rear of the motor..... hope this is of help
Dave
Yes I perfectly agree Dave, I would normally fit the coupling as straight as possible (see previous custom mounts), although on this test I just slapped it in to see about revs power and WIEGHT.
Yes as Nordlys has also mentioned, my original concern with this setup was the weight and the lack of RPM on the Hectoperm.
I will run it on Sunday as-is, and go from there.
If it looks good, then I'll likely shorten the shaft by 30mm (to shift the weight down and aft), make a shorter brass/rubber UJ, straighten the motor mount, and just run the Hectoperm.
Else...
If this motor/prop is still not an acceptable solution, I had considered a belt/gear (plane style) reduction as suggested by radiojoe, and could use either the Marx 300GT or another high power motor with the reduction drive, which would have to be the solution.
If I have to source another motor, I'll likely go brushless with reduction.
I don't want this to be a superfast speed boat, but go at a fun speed for with a bit in headroom if I need it.
The main issue so far has just been overloading the motors due to large prop direct drive with an undersized motor.
So putting the weight to one side for a moment, assuming the Hectoperm is up to it with the prop/gearbox, it will hopefully be acceptable.
Rgds
Jon
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What I forgot to put in my earlier post to you was the fact that in handling both
motors shown in my pictures, there was little difference in the weight!
The big difference between the two of course is one is low revving the other
much higher.
N.
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Thanks Nordlys,
That's an interesting point, about comparative weights.
I have tried a direct drive 700 size motor in it last year (18V power drill style),
but found that over heated too, maybe a motor quality issue, maybe just the prop couldn't rev enough, but it was not a good combo anyway.
We shall just have to see.
Jon
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Hope you don't mind me posting just a couple of pictures
of my Tarpon for your interest - with a motor I had in mind to use.
N
Thanks for the pics, yes appears to be very similar. Mine is 35" ling 9 1/2" beam.
Is this similar to yours?
Have you had it running with the Decaperm?
What prop have you got on it (about)?
Cheers
Jon
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one other pic I missed in case you are interested
N
Do you have any details on the "Darke Horse" motor tried a quick search but nothing has come up.
Looks a decent motor though, is it a 600 Can size?
Jon
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My Tarpon is unfinished and living in the loft at the moment!
I haven't had it running at all - I just put the Motors in the hull today to
show you the relative sizes.
I will check out that motor tomorrow and post again but it is larger than a 600
with a larger output shaft - 700 maybe?
Likewise no prop information either but then that shouldn't be a problem as a couple of
trial runs with one or two different sizes will sort that.
The motor came from Anglia Models but doesn't appear to be available now! Sorry not much help
tonight!
N
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Hi Jon, if it's any help, my pilot boat is a similar size to your Tarpon and running on the 600 motor and belt drive has a 50mm 4 blade brass prop that gives a good realistic speed. Joe
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My Tarpon measures 36" long x 10.5" beam. Very similar size to yours.
The motor I was showing in my photo was from Anglia Model centre
but on enquiry they have none in stock at the moment. Size was 785 6-18v with a 5mm dia shaft.
They do have a 700 Race Graupner 9.6v (£23) but I'm thinking you probably wouldn't need to use
a motor this large for the Tarpon.
A 600 size should be quite adequate - its quite a light weight boat, don't you think?
Hope this is of some help.
N
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I will check out that motor tomorrow and post again but it is larger than a 600
with a larger output shaft - 700 maybe?
...
The motor came from Anglia Models but doesn't appear to be available now! Sorry not much help
tonight!
N
Ive found a catalogue for "Darke Horse" from back in 2009, if it's the standard 700 frame one, then the spec is as follows:
6-18V, 5 Pole, High Torque, 785 Motor.
7,000rpm @ 6V 14,000rpm at 12V, 21,000rpm at 18V
http://www.rcgroups.com/forums/showatt.php?attachmentid=3609656 (http://www.rcgroups.com/forums/showatt.php?attachmentid=3609656)
I'm sort of hoping the Hectoperm is OK now
From what people have had success with, ~8K rpm (on charged 2S LiPo) and a 45mm 3 blade brass prop, appears to be in the ball park.
We shall find out on Sunday O0
Regards
Jon
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Well I've tested the Tarpon with the Hectoperm, and it was not too bad.
The bow was a little heavy, but a little more ballast in the aft and moving the motor a little further aft could sort this out.
I feel it could do with a little more RPM though, and the noise of the gearbox is a little too loud for me.
But it was a very informative test.
http://youtu.be/H2r9omQTW6s (http://youtu.be/H2r9omQTW6s)
The maximum draw was about 5A (~40W), max revs on the shaft ~ 3000 RPM at 8V
(Looks like the stated RPM of the hectoperm is the ungeared speed, I misunderstood this in a previous post when I said 8K (which would be unladen aswell)
At 550g the hectoperm is hefty, so I think if I can find an alternative solution I may give it a go.
I've re-varnished the deck now, and in the process of repainting all the rails and fittings.
I'll put some photos up in a tic when dropbox gets it's ;D sorted out.
I'll hopefully get the superstructure undercoated this week.
Need to make the new bowroller/fairlead, and work out exactly how to refit the mast (hole in deck is much larger than the mast) {:-{
Likley need to make a foot for the mast to angle it back, and make the two sizes compatible.
Jon
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As you said Jon, a bit noisy but the speed looks spot on for the type of craft, she looks very much at home on the water :-)) .Joe.
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I was about to comment on the 3000 rpm speed being a tad low but
on seeing the video and as Joe said it doesn't look that slow - which
surprises me!
Not my motor of choice and perhaps a little noisy have to admit,
but this is a very nice looking model and certainly runs very well.
I'd be pleased with that!
N
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Now my Dropbox appears to be working at more than a snails pace, I can put some links in of the photos...
(https://dl.dropboxusercontent.com/u/5915667/Model%20Photos/DSC04645.JPG)
The mark on the foredeck is just a flash shadow.
(https://dl.dropboxusercontent.com/u/5915667/Model%20Photos/DSC04646.JPG)
Cabin is sanded down, and I've just filled the few pocks/holes in in, so another sand down tomorrow and ready for the primer.
(https://dl.dropboxusercontent.com/u/5915667/Model%20Photos/DSC04652.JPG)
Rgds
Jon
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She's well on her way to looking like she should you have been busy Jon, nice work :-)). Joe.
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Hi Jon,
See if you can get your hands on an 'industrial' motor like this Bühler:
http://www.rc-point.nl/index.php?item=buhler-6-18-vdc-motor--12v-3030-toeren-1_7a--pakket&action=article&group_id=20000271&aid=69112&lang=nl#.U4m9CyhC1dw
Last year I used 14 of these motors in 140 cm long models and they run all day on a 12V 7Ah battery turning a Ø55 mm prop.
Regards, Jan.
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Can't modify my post above, so I'll add it here.
The Bühler works in direct drive, so you'll have a much quieter boat, I quickly had to dial down the volume, watching your 'floating table saw' rush by...
Regards, Jan.
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Hi Jon,
See if you can get your hands on an 'industrial' motor like this Bühler:
http://www.rc-point.nl/index.php?item=buhler-6-18-vdc-motor--12v-3030-toeren-1_7a--pakket&action=article&group_id=20000271&aid=69112&lang=nl#.U4m9CyhC1dw (http://www.rc-point.nl/index.php?item=buhler-6-18-vdc-motor--12v-3030-toeren-1_7a--pakket&action=article&group_id=20000271&aid=69112&lang=nl#.U4m9CyhC1dw)
Last year I used 14 of these motors in 140 cm long models and they run all day on a 12V 7Ah battery turning a Ø55 mm prop.
Regards, Jan.
I mentioned in an earlier post that I had a large industrial motor that I was thinking of using, but I thought it was slightly too large, and at 48V inconvenient.
It just so happens it's one of the motors you mentioned, albeit a 48V one.
The choice of motors I have that will likely work, it either the Bühler, or the Marx GT300 (Taken next to a stock 540 for comparison)
(https://dl.dropboxusercontent.com/u/5915667/Model%20Photos/2014-05-31%2014.26.32.jpg)
The Bühler needs 28V to make 3500 RPM, while the GT300/10 only needs 5V to do 3500 RPM, my gut feeling is neither of these is ideal, bit I may fit the GT300 and take it to the pool tomorrow to test anyway.
I know the GT300 is totally excessive, hell 4 of these will power a 1:6 scale C-130 Hercules apparently.
Other option is to knock up a belt reduction for a 540, as I think a 500 can operating at the designed RPM will have adequate power.
The hectoperm was only drawing 30 odd watts, so a 500 should be more than capable, and much lighter than a low RPM direct drive larger motor.
Rgds
Jon
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Just had a better look at the Bühler link, and my Bühler motor is considerably larger.
Mine is 54x107mm
I do have another Bühler motor I've just located, appears to be a 600 can size (36.6mm can), and gives ~4K RPM with 14V,
I believe it to be a 48V motor also, so it would be well out of it's nominal operating range.
So IF this was powerful enough it may be an option.
(https://dl.dropboxusercontent.com/u/5915667/Model%20Photos/2014-05-31%2017.14.27.jpg)
I struggled to stop the pinion with a pair of pliers at 14V, and it was drawing ~2.5A during that.
Just a pain it's going to have to be 4S lipo, or a pair of racepacks to try it out, and my current ESC is only rated to 12V, so that's a pain too.
Guess I could try it on 10 cell (max stated by ESC) to see how it goes.
All of these motors were out of a Xerox Phaser Wax printer.
Rgds
Jon
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Hi Jon,
Yes, those Bühler motors are generally torque monsters.
If you have 3S Lipo's at hand, give those a try first, you won't exceed the ESC limits.
When the GT series came out, they were a sensation, really large commutors with large brushes which could handle the 300W all day long without overheating (in a plane).
The have also been used in boats, but the limited cooling proved to be an issue in competition boats.
If you would run the GT300/10 (730Kv) on 3S and used a belt reduction 1:2, you'd have about 3300 rpm under load and the motor wouldn't even get warm...
On 4S, the 4000 rpm would make it a very fast cruiser.
Regards, Jan.
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Well I just got back from the boating pool (Worcester Country Hall), and I believe I have a successful combination on the Tarpon.
The 600 can Bühler motor appears to be just right, running on 4S, pulling 2.75A peak (so ~45W) and giving a good scale speed in near silence.
After 10 minutes or so of running the motor was slightly warm to the touch, so no over heating problems which is great.
I may try 5S (21v Charged) just to see if it has any benefit, but 4S (16.8V Charged) was perfectly acceptable.
5S may just give me a better speed when the batteries are down at their nominal voltage, as 5S nominal is only a bit above the peak charge of 4S, so Thinking about it5S may be better, and just not throttle it full when the batteries are fresh.
(https://dl.dropboxusercontent.com/u/5915667/Model%20Photos/WP_000055.jpg)
After I blew up the second MTronics 'Marine 20' when running on 12V, I moved to my Electronize ESC to test the boat.
These are rated to 24V, so no issues with voltage, and I've replaced the FET with a very low RDSon so should it shouldn't heat up much either.
(https://dl.dropboxusercontent.com/u/5915667/Model%20Photos/DSC04697.JPG)
On the subject of the MTronics 'Marine 20' this second unit was a warranty replacement for the 1st unit, I ran the 1st unit on 3S LiPo, and the unit failed very quickly.
This one I was bench testing the Bühler motor on a lead acid battery (12V), and it lasted less than five minutes. Not impressed. I was not overloading the ESC in either case (<1A on the second time), so I can only assume they are just rubbish.
Ive also got a first coat of paint on the cabin, and the mast is erect for the 1st time in a few decades I would think.
Just need to order some acrylic for the windows, a new searchlight, and some brass NAVlights I can put LEDs in.
(https://dl.dropboxusercontent.com/u/5915667/Model%20Photos/DSC04695.JPG)
(https://dl.dropboxusercontent.com/u/5915667/Model%20Photos/DSC04696.JPG)I'll try to get another video done soon, to show the improvement over the Hectoperm.
Jon
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Nice!
Looking forward to the video.
Regards, Jan.
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Well I was going to put up a video today of the new motor BUT.....
I lost my prop after a full astern collision avoidance event this morning. >:-o
I'd locknutt'ed it up, but obviously not enough for the high torque motor now running on 5Cell LiPo.
Bit it was great before the event, bow was lifting nicely, stern was not digging in too deep, and the speed was great at 3/4 throttle.
Same really as it was a 1950/60's cast prop that looked really well built.
Looks like I now need to find a suitable replacement.
So I likely need a 55mm 3 blade brass.
Oh well these things happen....
Jon