Model Boat Mayhem

The Shipyard ( Dry Dock ): Builds & Questions => Pleasure boats, Sports, Race, Power and Leisure Boats: => Topic started by: Patrick Henry on April 23, 2010, 01:17:08 pm

Title: Thimble...
Post by: Patrick Henry on April 23, 2010, 01:17:08 pm
Anybody remember a fast electric called "Thimble", designed by Les Jones? It goes way back in time...anybody ever build one?

I think I might have a go at it...what do you reckon, fellas?


Rich



Title: Re: Thimble...
Post by: knoby on April 23, 2010, 06:26:59 pm
hi rich, I had 2 of them. Built the first 1 from the plan, had a cyclone 20 in it & 8 saft bvy cells. To be honest it never realised its true potential for me, it was a g8 boat,for naviga steering but due to its small length it wasn't to happy in any form of choppy water. also had a habit of submarining itself. At the time there were very limited motors & props available so it was hard to develop its potential. that said it ran well on a p30 prop.

The second 1 was a lot different. I won a fiber glass hull for 1 in a club raffle. the glass was so thick it was never going to be a viable electric racing boat, so i put an OS 10 ic in it. That was much more like it !!! a real handful to drive but great fun. Eventually it obliterated itself when it lost an argument with a concreate jetty.

It certainly wouldn't be competitive with modern Eco hulls, but I'm sure it would make a good performer using modern hardware & they are easy to build.

Sorry cant find any pics, Ill ask the 'old man ' see if i cant find some

cheers Glenn
Title: Re: Thimble...
Post by: Patrick Henry on April 23, 2010, 06:38:06 pm
Good grief Glenn, I never expected anyone to have heard of Thimble, let alone have two of them! I thought it may be make a good fun type boat(after the failure of my airboat)to throw in the car and have something to charge about the lake with.

I built it's bigger brother 'Squadge' many years ago, that was fun...nothing dramatic and certainly not that competitive, but just a fun boat.

I've ordered the plan, got the Tamiya motor, got a shaft and coupling, battery pack and a couple of props, the only change I think I may make is use plasticard instead of wood...I hate wood and it hates me!

I'd appreciate a pic or two if you can find any...cheers Glenn,


Rich
Title: Re: Thimble...
Post by: knoby on April 23, 2010, 06:46:25 pm
Hi Rich, I was a memeber of milton keynes model society at the time & there were a few of them in the club. I beleive it was a free plan in model boats with a feature around late 70's early 80's, but cant be more specific than that.
I'll certainlky look  for the pics, but if they exist my dad has them & it will take a while to get to him , find them & scan them  so dont hold your breath.
Always thought they'd make a great 1 make class, & with modern motors & cells it would be fun.
By the way, when you float 1 for the first time dont be alarmed it most of it seem underwater, they all were like that
 cheers Glenn

Title: Re: Thimble...
Post by: Patrick Henry on April 23, 2010, 06:53:01 pm
I know it was a good few years ago when the plan was published Glenn, I remember seeing Les Jones at a Cygnets race meet at Mote Park in Maidstone with the prototype of Thimble...it was that small and that low in the water other competitors had a job seeing the perishing thing! It was quite impressive though for a tiny boat, it flew round the course and made a few other drivers take notice of it, especially when it passed a few of them!

Thanks for your help Glenn, much appreciated...

Rich
Title: Re: Thimble...
Post by: Subculture on April 24, 2010, 05:20:30 pm
I think the 'bug' by Nick Rees is a much better boat.
Title: Re: Thimble...
Post by: Patrick Henry on April 24, 2010, 07:37:19 pm
Maybe it is...but it's not what I want, Andy.


Title: Re: Thimble...
Post by: normanoo4 on October 23, 2011, 07:16:14 pm
this plan is listed here

http://www.myhobbystore.co.uk/browser/997/rc-competition

norman

Title: Re: Thimble...
Post by: Patrick Henry on October 23, 2011, 07:22:24 pm
Thanks Norman, I have the original plan and the magazine write up for Thimble.

I bet it wouldn't half go with a brushless/lipo set up...hmm.


Thanks for the link anyway, much appreciated.





Rich
Title: Re: Thimble...
Post by: Patrick Henry on February 03, 2012, 01:32:32 pm
It's that nostalgic moment...

May I present Thimble...with an original Cyclone 15 motor, built to plan specs with the alloy turn fin and a 30x plastic prop.

And before you ask, I didn't build it, I picked it up on ebay for £14. Vintage racing, anybody?


(http://s14.postimage.org/3rjb8hyjx/03022012395.jpg) (http://postimage.org/image/3rjb8hyjx/)

(http://s7.postimage.org/nxuj20cxj/03022012396.jpg) (http://postimage.org/image/nxuj20cxj/)


Rich
Title: Re: Thimble...
Post by: Subculture on February 03, 2012, 01:53:03 pm
Small pack of 2S lipo, ESC, mini servo and 2.4ghz RX and it should go better than the original equipment, with a big weight saving.

The hull could handle more, but what about the operator?
Title: Re: Thimble...
Post by: Patrick Henry on February 03, 2012, 02:09:07 pm
Small pack of 2S lipo, ESC, mini servo and 2.4ghz RX and it should go better than the original equipment, with a big weight saving.

The hull could handle more, but what about the operator?

I'd kinda like to keep it original, I think...Les's original version had two four cell packs of 1.2v 1.2a/h cells, and a servo operated microswitch set up for speed control. Ooh...no, I lied...it had TWO microswitches, one for full power and the other via a resistor for half power. It ran for a smidge over four minutes on a fully charged cell pack.

Now...who was it...a chap called Paul Bridgewater, I think...he built a Thimble with a ic motor in it. Now that was hairy...I believe it had an OS .15 motor in it. And I think I'm right in saying that Les had an ic powered version as well.

As for this operator...well, it'll be doubtful if he could handle it with a lipo pack in it, and I'm pretty sure that the lake owners wouldn't like it either. Remember the troubles I had with George and his Robbe Jet Ski?



Rich

Title: Re: Thimble...
Post by: Subculture on February 03, 2012, 04:03:35 pm
The lipos won't deliver significantly more juice than the Nicads, in fact slightly less, because it will be 7.4 volts instead of 9.6 volts.

I find a 2S 5A 15C pack of Lipo's takes up the same sort of footprint as an old 7.2 volt pack of sub-c nicads, but weighs less and lasts for four times longer. Instead of a few minutes of frantic fun, you'll get half an hour or more.

The weight saving shold help handling, and top speed.

An esc will give you better speed control without the built in central heating.

But it's your boat. I like to see old designs, but I think they're more exciting when paired up with the advances in technology, which were just a pipe dream back in the '70's.

Title: Re: Thimble...
Post by: Patrick Henry on February 04, 2012, 08:10:47 am
Now, here's interesting...further to the discussions above, I've discovered this little electronical "thing".

I'm thinking it may be a BEC?

(http://s13.postimage.org/gzc674to3/switch.jpg) (http://postimage.org/image/gzc674to3/)


Rich
Title: Re: Thimble...
Post by: Patrick Henry on February 04, 2012, 08:16:13 am
There's also this little device...I guess a home brewed esc?


(http://s16.postimage.org/3p2k27o7l/04022012401.jpg) (http://postimage.org/image/3p2k27o7l/)

(http://s13.postimage.org/t7z19lg6r/04022012400.jpg) (http://postimage.org/image/t7z19lg6r/)

(http://s14.postimage.org/tynml0a4d/04022012399.jpg) (http://postimage.org/image/tynml0a4d/)

(http://s13.postimage.org/vf39xilgz/04022012398.jpg) (http://postimage.org/image/vf39xilgz/)
Title: Re: Thimble...
Post by: knoby on February 04, 2012, 09:51:45 am
Hi Rich, nice to see a Thimble again. I used to race the Naviga Christmas tree course with one of these back in the day when i had quick reactions  :-))
It had 2 speeds, stop & go.
I think the second 'Gizmo' is an electronic switch for motor, the esc's at that time weren't up to the job, so most people used a servo operated micro switch or an electronic switch.
The first item, i am not so sure about, but my hunch is its a BEC.
Personally, I am with you & would run it as it was designed, although I would be tempted to use a higher capacity cell that 1.2 ah. as the run times were very short. That said with a small brushless set up & lipo's, I am sure it would surprise a few people.

Cheers Glenn
Title: Re: Thimble...
Post by: Subculture on February 04, 2012, 11:00:38 am
First item looks like a BEC to me. Second item looks like a relay switcher for motor control.
Title: Re: Thimble...
Post by: Patrick Henry on February 17, 2012, 10:34:06 am
It's Thimble time...she floats (which surprised me, to be honest)


Let's recap...
Les Jones's original design was for a Cyclone 15 motor, 8x 1.2v, 1.2 a/h nicads, a plain 35mm prop, standard sized rudder servo and another one with two micro switches for half power/full power.

Mine now carries the original Cyclone 15 motor, 8X 1.2v, 2500 a/h NiMhs, same prop, an MMB micro servo for the rudder and an esc set up to give 100% power on going ahead and 25% astern.

Thimble has just got her undersides wet for what could well be the first time in a lot of years, and she floats just above the designed waterline, which is a bonus...I was nervous of putting her in the bath, because she did feel rather heavy.

Next is the maiden voyage on the 'proper' lake, Princes Park in Eastbourne.

(http://s14.postimage.org/a5g5tnqx9/17022012452.jpg) (http://postimage.org/image/a5g5tnqx9/) (http://s14.postimage.org/582l8joy5/17022012453.jpg) (http://postimage.org/image/582l8joy5/) (http://s17.postimage.org/sih7nlicr/17022012454.jpg) (http://postimage.org/image/sih7nlicr/)
Title: Re: Thimble...
Post by: Patrick Henry on February 17, 2012, 12:31:53 pm
As an afterthought to this, I wired up the battery packs, hooked everything up, switched on and put the boat back in the bath.

Two clicks of throttle...forward motion. Good...half throttle, and Thimble is starting to climb up the end of the bath. Ok so far... so onto full throttle (with me hanging onto the stern) ....best part of a bath full of water rapidly transfers itself up the walls, over the window and the windowsill, on the floor, and over me.

I guess we can say it works....





Rich (and wet....)
Title: Re: Thimble...
Post by: cuppa on February 17, 2012, 01:33:59 pm
As an afterthought to this, I wired up the battery packs, hooked everything up, switched on and put the boat back in the bath.

Two clicks of throttle...forward motion. Good...half throttle, and Thimble is starting to climb up the end of the bath. Ok so far... so onto full throttle (with me hanging onto the stern) ....best part of a bath full of water rapidly transfers itself up the walls, over the window and the windowsill, on the floor, and over me.

I guess we can say it works....
Rich (and wet....)

My grandson did a similar thing with the piranha in the kitchen sink. It is amazing how far a model boat can blow water out of a sink or bath tub! My wife suffered a complete sense of humour failure when she saw the resultant flooding..............
Title: Re: Thimble...
Post by: tr7v8 on February 17, 2012, 01:52:44 pm
That looks great fun, not sure if our waters would be suitable for something that small.
I've always liked the Vic Smeed Mocassion design & will build it one day.
Title: Re: Thimble...
Post by: Patrick Henry on February 17, 2012, 02:22:36 pm
I remember Les Jones, John Cundell and Paul Bridgewater racing these things at Mote Park in Maidstone way back when....three feet out from the edge and you'd lost sight of them!

Our small lake would be ideal for Thimble type boats, but the council (who own the lake) frown upon such things. I was asked politely (or told in no uncertain terms) not to run George (my Robbe Sea Jet) any longer, they even keep an eye on guys with fast patrol boats and the like.

I'm looking forward to giving Thimble a run, I did build her larger sister Squadge (another Les Jones design) that was quite good fun to run.


Rich
Title: Re: Thimble...
Post by: John East on March 02, 2012, 08:57:02 pm
Hiya..I to have two of these, and one of them is the one in the first picture on here ! The actual boat. I was a member of cygnets way back. I also have a moulded one. will dig them out, one still has all the original fitting in it.
Title: Re: Thimble...
Post by: victor on August 11, 2013, 08:58:06 am
Sorry to dig up an old thread but in sorting out my loft I came across a Nick Rees " The Bug " plan which I thought I would build using up to date internals and as the boat is mentioned above I thought this would be a good place to ask a favour.
 
The plan is fairly straight forward but there are one or two areas that aren't clear, could anyone help out with building notes or a mgazine article?
 
Thanks.
Title: Re: Thimble...
Post by: kiwiazz74 on November 28, 2018, 09:02:12 am
G'day guys I too am interested in building a thimble.
If anyone with plans and article  would be able to scan it and email to me i would be greatful and happy to pay for their time.
I did find the plan online at sarik i think but with $1nz = 50p plus post it makes the drawing a bit too expencive for me on a  pension.


cheers from NZ
Title: Re: Thimble...
Post by: colh107 on September 19, 2019, 07:17:28 pm
Waaaayyy old thread, but I remember the Thimble article from my youth. I've just got hold of the original mag with article/plans [even have a spare copy if anyone is interested].
It's exactly how I remember, but I'm thinking some modern materials/techniques could work well - things like a 540 motor mount, and a rudder/servo box, could probably be 3D-printed? Carbon fibre turning fin?  ok2
Maybe even 3D-print the bows, rather than sanding blocks of balsa?
And with the better weights these days of RC and batteries, it ought to be a breeze to bring new life to the design?
Drop me a line if you have an interest and/or would like to talk over 'modernisation' concepts!


PS - Also have Zing Ray plans, recalled from my youth too. Am debating which one to have a crack at!

Title: Re: Thimble...
Post by: kiwiazz74 on September 19, 2019, 08:11:22 pm
colh107 you legend i was so surprised to see a reply to this thread  this morning
after alot of time searching i ended up finding my thimble plan, but then i found naviga and mini eco's,
being at the bottom of the world with no naviga here and no one to race against i ended up shrinking down the plans i downloaded for a 1kg boat the "weisel" to mini eco length and have started building that instead of the thimble, running 3000kv brushless and 3s batteries.
as usual with me its a long term project but its been a fun build so far, will have to post a pic of it finished in here.
Title: Re: Thimble...
Post by: colh107 on September 19, 2019, 08:28:07 pm
Hehe thanks  :-)
It's a pet/embryonic project idea at the mo. I've not built from scratch before, but it always seemed a pretty straight-forward design. And whilst not having built wooden boats from scratch, I reckon my woodworking/engineering skills are up to the challenge. (Winter here soon...)
I reckon modern materials/gear can keep it definitely light.
I like that it's a 'pocket rocket'. Zing Ray also always appealed to me as a kid though - also pretty simple to build (and a Vic Smeed design, so gotta be decent).

Title: Re: Thimble...
Post by: rnli12 on September 19, 2019, 08:36:36 pm
WoW- built one for my CSE Woodwork exam in 1978 ish passed with a grade 2 i think......

Title: Re: Thimble...
Post by: Subculture on September 19, 2019, 10:03:50 pm
Francis Costin used to call wood 'Gods plastic'. Very difficult to beat for weight to strength.

If you built it as per plan, give the exterior surfaces a coat of epoxy resin and light glass tissue (25gm2) you'll have very light but strong hull that is waterproof.  Substitute the 500 size brushed motor for a brushless outrunner and lipo, a tiny 2.4ghz receiver with a 9 gram servo and  a forwards only esc the performance should be very lively.
Title: Re: Thimble...
Post by: colh107 on September 20, 2019, 03:34:43 pm
Francis Costin used to call wood 'Gods plastic'. Very difficult to beat for weight to strength.

If you built it as per plan, give the exterior surfaces a coat of epoxy resin and light glass tissue (25gm2) you'll have very light but strong hull that is waterproof.  Substitute the 500 size brushed motor for a brushless outrunner and lipo, a tiny 2.4ghz receiver with a 9 gram servo and  a forwards only esc the performance should be very lively.


Definitely with you there - unless rotten, you can always repair wood. (And if there's rot, cut it out and fit a new section! I'd rather repair a wooden door frame than uPVC).
Real wood only, of course - weight/strength of MDF..... WoW who invented that.... I had a 60yr old wardrobe with 2x2 frame and 1/8 skins, joints never came loose and I could pick it up alone. Not like modern rubbish that falls apart after a couple of moves and takes two+ to shift. Rant over lol.....  >:-o


Not sure about going brushless - I don't mind if it's 'gentle'  :embarrassed:

Title: Re: Thimble...
Post by: Martin [Admin] on September 20, 2019, 05:19:50 pm
 
(https://www.sarikhobbies.com/wp-content/uploads/images/products/p-19613-0024262_thimble-mm1294.jpeg)

https://www.sarikhobbies.com/product/thimble-mm1294/
Title: Re: Thimble...
Post by: colh107 on September 20, 2019, 05:51:24 pm
I managed to get hold of a copy of the '79 Model Boats mag - article and the plans too.
In fact, concern over reliability of the first vendor means I now have two copies!  %)

Scary that all the Ripmax/Graupner/SHG ads still seem sooooo familiar.... And o m g  - MacGregor RC too!!
2-channel txrx, with servos, for £82 - that was a fair amount for a hobby back then  {:-{



Title: Re: Thimble...
Post by: colh107 on October 05, 2019, 06:21:46 pm
Francis Costin used to call wood 'Gods plastic'. Very difficult to beat for weight to strength.

If you built it as per plan, give the exterior surfaces a coat of epoxy resin and light glass tissue (25gm2) you'll have very light but strong hull that is waterproof.  Substitute the 500 size brushed motor for a brushless outrunner and lipo, a tiny 2.4ghz receiver with a 9 gram servo and  a forwards only esc the performance should be very lively.


I should have paid more attention to my Dad when he reconstructed a Graduate in the 80s! Ive built much in wood but never combined with epoxy coating. Can you give some tips/links on how to go about that?
Title: Re: Thimble...
Post by: Subculture on October 06, 2019, 10:14:44 am
Have a look at this guide. You only need the lightest cloth 25gm2, as the strength will already be in the wood, maybe apply two or three layers on the balsa areas as that is softer than the ply.

https://www.bucks-composites.com/sites/bucks-composites.com/files/how-tos/Surface%20Finishing%20with%20Glass%20fibre%20Woven%20cloth%20%26%20Epoxy%20Resin_0.pdf
Title: Re: Thimble...
Post by: dreadnought72 on October 06, 2019, 10:34:37 am
.... And o m g  - MacGregor RC too!!
2-channel txrx, with servos, for £82 - that was a fair amount for a hobby back then  {:-{



Just shy of £410 in today's money!  :o


Andy
Title: Re: Thimble...
Post by: colh107 on October 14, 2019, 05:01:27 pm

Continuing (hopefully) some conversation that started here (https://www.modelboatmayhem.co.uk/forum/index.php/topic,63864.0.html), wrt Thimble in particular:


Colin Bishop: "It's just that looking at the plan profile you have posted any sort of 540 would seem to be putting a lot of weight well up up front"
I understand the comment, but the design was originally for a Cyclone 15. Looking at back issues of Model Boats, those were 150g so about the same as a 540. C of G can be adjusted a bit of course to get it back in the 'right' place, though the plans don't unfortunately show where that should be...! (Maybe there's a 'rule of thumb' for that?)


Subculture: "Motor and speed controller can be had for under a tenner"
I may (more than likely) be looking at wrong vendors or wrong motors, but even smallish brushless seemed to me to be starting at more like 30 quid or so?
You suggested 'outrunner'. I ought to go trawling info myself but, as you know your stuff, any particular reason for out rather than in?


BTW, I'd be content and happy with 'fun performance' - 'very exciting' not necessarily needed!
Title: Re: Thimble...
Post by: DaveM on October 14, 2019, 05:43:51 pm
Ive built much in wood but never combined with epoxy coating. Can you give some tips/links on how to go about that?
Here's a bit of relevant nonsense... https://www.modelboats.co.uk/news/article/finishing-and-sealing-of-wooden-hulls/18771 (https://www.modelboats.co.uk/news/article/finishing-and-sealing-of-wooden-hulls/18771)
DaveM
Title: Re: Thimble...
Post by: Colin Bishop on October 14, 2019, 06:02:17 pm
There is a useful article on Brushless on the Model Boats site:

https://www.modelboats.co.uk/news/article/going-brushless/8029 (https://www.modelboats.co.uk/news/article/going-brushless/8029)

I have only recently got into brushless myself as a result of building the SLEC Huntsman kit last year. I used Dave Milbourn's recommendations for the power setup and the boat goes like a rocket. OK, it's a bit of a learning curve but not really difficult when you get down to it.

This little Turnigy motor produces an amazing amount of power for its size:

https://hobbyking.com/en_us/d2830-11-1000kv-brushless-motor.html?___store=en_us (https://hobbyking.com/en_us/d2830-11-1000kv-brushless-motor.html?___store=en_us)

Outrunners are usually recommended for boats as the design produces more torque than inrunners which is handy for marine props.

I did use a fairly pricey speed controller from Component Shop but there are cheaper options out there.

As far as weight is concerned, a brushless/LiPo setup will be much lighter but you can always add a bit of ballast if it turns out to be necessary so your options are open.

Having said all that I'm still happy with brushed motor/NiMH batteries for my scale models which only need to plod along.

Colin
Title: Re: Thimble...
Post by: colh107 on October 14, 2019, 06:07:27 pm
Ive built much in wood but never combined with epoxy coating. Can you give some tips/links on how to go about that?
Here's a bit of relevant nonsense... https://www.modelboats.co.uk/news/article/finishing-and-sealing-of-wooden-hulls/18771 (https://www.modelboats.co.uk/news/article/finishing-and-sealing-of-wooden-hulls/18771)
DaveM


Thanks. WoW that article digs so much terminology from the depths of my memory! 'Sanding sealer', Eze Kote

Title: Re: Thimble...
Post by: colh107 on October 14, 2019, 06:12:27 pm
There is a useful article on Brushless on the Model Boats site:

https://www.modelboats.co.uk/news/article/going-brushless/8029 (https://www.modelboats.co.uk/news/article/going-brushless/8029)

I have only recently got into brushless myself as a result of building the SLEC Huntsman kit last year. I used Dave Milbourn's recommendations for the power setup and the boat goes like a rocket. OK, it's a bit of a learning curve but not really difficult when you get down to it.

This little Turnigy motor produces an amazing amount of power for its size:

https://hobbyking.com/en_us/d2830-11-1000kv-brushless-motor.html?___store=en_us (https://hobbyking.com/en_us/d2830-11-1000kv-brushless-motor.html?___store=en_us)

Outrunners are usually recommended for boats as the design produces more torque than inrunners which is handy for marine props.



Thanks for that steer - I've been gazing at their site several times today without seeing that. I think I'm going 'motor blind'! Does look neat and well-priced, and might be enough for a Thimble for me. Though I see there's also a 2200kv version at similar price bracket.

Title: Re: Thimble...
Post by: Subculture on October 14, 2019, 06:20:33 pm
I use these for a 2s setup

https://www.ebay.co.uk/itm/201102472824?ul_ref=https%253A%252F%252Frover.ebay.com%252Frover%252F1%252F710-53481-19255-0%252F1%253Fff3%253D2%2526pub%253D5575376664%2526toolid%253D10001%2526campid%253D5338268676%2526customid%253DEAIaIQobChMI25n0i6Cc5QIVxrTtCh04zgABEAsYAyABEgKSdPD_BwE%2526lgeo%253D1%2526item%253D201102472824%2526srcrot%253D710-53481-19255-0%2526rvr_id%253D2144246853992%2526rvr_ts%253Dcb44d77216d0aad6a742ff80fff603cb&ul_noapp=true

For a 3s system I use the slower revving motor, which is also a bit torque rowing to the deeper armature.

https://uk-m.banggood.com/EMAX-CF2812-1534KV-Brushless-Outrunner-Motor-For-RC-Model-p-981249.html?gmcCountry=GB&currency=GBP&cur_warehouse=CN&createTmp=1&utm_source=googleshopping&utm_medium=cpc_bgcs&utm_content=garman&utm_campaign=ssc-gbg-summersale-all&utm_design=152&ad_id=358675083520&gclid=EAIaIQobChMI25n0i6Cc5QIVxrTtCh04zgABEAsYASABEgISNvD_BwE

 Donít forget a brushed motor has very large magnets and a commutator and brush assembly increasing bulk.
Title: Re: Thimble...
Post by: Colin Bishop on October 14, 2019, 06:23:12 pm
There are others more competent than I am to recommend a suitable setup for Thimble. I initially put a 3S LiPo in the Huntsman but it was a bit too fast for my current reflexes so I replaced it with a 2S which still gives a pretty brisk planing performance.
( Edit: Just seen Subculture's advice above)

Colin
Title: Re: Thimble...
Post by: colh107 on October 14, 2019, 06:33:23 pm
Thanks all. So, from Subculture's mention of it yesterday - at what point does supplemental cooling become necessary? I guess for an outrunner that doesn't have it built in, you'd only be able to sink the heat away through its mounting bracket(s)....?

Title: Re: Thimble...
Post by: Subculture on October 14, 2019, 07:23:07 pm
These size brushless motors are good for about 100-150 watts. At about 70-80% efficiency, that means the potential for 20-45 watts being burnt off in heat, so some form of cooling is advised. I find just a small copper pipe with some thermal connection to the motor is adequate to keep things cool. A pick up just behind the prop draws in the water. Simple and cheap to implement. I use no heli or Simon K firmware escís, very cheap on eBay and super smooth throttle control. N- channel mosfet stages run very cool, and donít require any additional cooling.
Title: Re: Thimble...
Post by: colh107 on October 14, 2019, 07:31:31 pm
These size brushless motors are good for about 100-150 watts. At about 70-80% efficiency, that means the potential for 20-45 watts being burnt off in heat, so some form of cooling is advised. I find just a small copper pipe with some thermal connection to the motor is adequate to keep things cool. A pick up just behind the prop draws in the water. Simple and cheap to implement. I use no heli or Simon K firmware escís, very cheap on eBay and super smooth throttle control. N- channel mosfet stages run very cool, and donít require any additional cooling.


Ah, some terminology I am familiar with  :-)  (N channel MOSFETs, firmware). I even know how to calculate theta JC's etc lol
Thanks guys. :-))

Title: Re: Thimble...
Post by: Colin Bishop on October 14, 2019, 07:42:32 pm
I've not had any cooling issues with my Huntsman but I doubt if I am running the motor at anywhere near full power and not continuously for several minutes as you would under racing conditions.

Colin
Title: Re: Thimble...
Post by: colh107 on October 14, 2019, 07:51:58 pm
I've not had any cooling issues with my Huntsman but I doubt if I am running the motor at anywhere near full power and not continuously for several minutes as you would under racing conditions.

Colin


I guess you also have a larger air space in that compared with summat like a Thimble, which would help to some degree [no pun intended].

Title: Re: Thimble...
Post by: Subculture on October 14, 2019, 09:27:28 pm
Unless you're winding a pretty large prop, a 1000kv motor at 7.4volts won't be working the motor very hard at all, so air cooling will more than suffice. Remember also  that with the extended running time lipo's allow, things have more time to get toasty. In the old days of nicads, five minute runs were the norm, now you can easily get fifteen to twenty minute runs.

BTW, my previous post should have said 'BL heli' esc instead of no heli. The auto correct on my phone struck again!