Paddleducks
Paddler Modelling => Paddlewheels/Drive Systems => Topic started by: Broder Incertus on October 09, 2013, 04:46:14 AM
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Greetings,
Again contemplating what to build next, one idea is some sort of paddle tug (say something dieselpunk-ish inspired by modern Russian paddlers, e.g., http://img-fotki.yandex.ru/get/5107/vladimi-shulae.5/0_52e95_7b7090ce_orig and http://www.riverfleet.ru/fleet/list.php?SECTION_ID=3156), more or less Graupner Glasgow sized using Graupner paddle wheels (or something similar). But the motor+gearbox I've used before seems to be discontinued (the Pile-Mot used in the Glasgow), so what to use instead? Are there any suitable quality gearboxes available? Preferable something you can use with the motor of your choice, and for independently driven paddle wheels. Tank hardware?
tia/tm
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Look on Ebay for replacement Heng Long gearboxes. I've bought several for various jobs and for the price the quality is excellent. A pair of gearboxes with motors for less than 12.00GBP, bargain!
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Isn't the diameter of the output axis of the Heng Long (tank) gearboxes on the largish side (8 mm or so)? Making the use of off the shelf timing belt pulleys harder?
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That's true but the output speed is around what you need for paddlers so you could mount the wheel directly to the gearbox or drill out the belt drive wheel to fit the Heng Long shaft which is 8 mm. The advantage of the gear box is the torque. To directly drive the wheel you need a fairly high torque motor. The Heng Long motors are 6V 340 can motors and the torque is gained through the gear train but with large power requirements. By using both boxes you can achieve "tank steering" quite easily and they look pretty cool when they're fitted.
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Haven't really got the proper tools to trill out anything that size, and I'd guess the Graupner paddles wouldn't take kindly to that kind of treatment (but I could be wrong: happens most days). How easy is it to replace of the original motors? I've standardised on 3s and 4s LiFe batteries, and given the price of those I rather use the ones I have than buy a set of 2s. (A 6V motor on almost 10V would require additional gearing and run rather hot IIRC the bad old days doing nasty things to 6V SPEED 400s in parkflyers)
Perhaps there are some robot kit parts that could be used ... (though most of what I've found is rather lower power stuff – or very high power ...).
Apart from Heng Long tank gearboxes, what else is used? I've think I've seem Bühler motors being mentioned, but which Bühler motor(s) and where do you buy these?
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have you thought about building your own paddler g/boxes ??
you can get tooth belt sets in MXL pitch at reasonable $$ approx. 50mm CtoC , or graupner gear sets in 3:1 ratio
mount these in a Alum. channel , slot the motor mount holes to allow adjustment of gear mesh or tension t/belts , mount the second set to form a Vee of 90 degrees between the 2 gear sets , then a HTD t/belt set of 3:1, from this mounted in the bottom of the hull, up to the paddle drive shaft , this gets your motors down low in the hull.
i have build a similar set up to this for a aussie paddler drive , not yet in the model .
regards bill s
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I have thought about it and dismissed the thought (the gearing I did for my one and only steam powered paddler is strictly DIY using timing belts – not working well; the gearing for my twin prop tug is also OD using timing belts – working very well).
I have found a geared motor intended for robots that seems to fit the bill at a reasonable price (about the price of two timing pulleys from HPC) and it's even sold locally.
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its not that hard to build your own g/box , if you use t/belts , they need to be adjustable tensioned .
first reduction , simply slot the motor mount to allow a small movement (5mm?) of the motor , can be done w files
the first and second shaft need to be supported on the other side of the motor by a second alum. plate , this can be done w 3mm brass all thread bolts inside 6 mm brass spacers/columns
second reduction has the Centre to C distance , just slightly shorter than required too tension belt (-2mm?), to allow you to just squeeze the belt on , you then fit a flat pulley on a adjustable arm , to final tension belt , on its back side , last reduction is from g.box to paddle shaft ,using HTD t/belts
inside g/box use MXL belts , you tune the set up w different motors+speed control
jaycar in Australia make a 550motor+spur gear box ,in a ratio that is too slow , so we over drive the t/belt ratio to get paddle wheel revs ,1:2 say
aiming at 300-350 rpm
regards bill s
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P'haps not that hard, but I'd need to build two 3-stage (or 4-stage) GBs to fit in a fairly small space, and I'd need four (or six) more pulleys than using an off-the-shelf GB, at about £10 per pulley: one of the Pololu 37D geared motors ought (!) to work, and they're less than £20. And good ol' KISS, with emphasis on the last S :-).
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good luck , you have some options , and alternative ideas , let us know what works .
i have a 300 rpm motor +g/box from ebay , via china , to test for another paddler drive ,1 per paddle wheel , but on that hull ,. i`m trying concealed props , for full power only ,drive , due too the wind we get at our lake ,just to give me steerage way
will shape 2 1/2 circles in the bottom of the hull, to half conceal props , for any shows , i doubt any-one will pick it up , but i can block cut outs w false plugs.
i like to try different ideas w new models , only for the wind ,i wouldn't bother , model will be fitted w plastic paddle wheel kits from float a boat au
regards bill s
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Hi PD's ....& hullo Bill + Broder :whistle.....yes windage can play havoc with steerage on our OZ paddlers especially the likes of PS Marion..........the skipper of which in a Video compares the windage effect on Marion even on a sheltered Murray river to an ocean going yacht under full sail.....many images of Marion depict her on a 5 ++ degree inclination as she rounds a bend....and is exacerbated by relatively low water velocity from the paddles over the barn door rudders as opposed to propeller flows mounted just in front of the rudders :oops
In theory.....adding a pair of concealed propeller's should help ....but I am not sure I would recommend them...........do we really want a paddler to turn like a tug boat?
Possibly the lessor of two evils would be an ACTion manufactured mixer & speed controllers for each paddle motor........to achieve the same or similar result?........I tried it many years ago....however felt the setup was too touchy & very much a tank type drive
Please keep us posted on your progress/s..........Derek :beer
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gday derek ,
i think i meet you at Renmark , for the anniversary for industry , hello again .
it is a option to fit a electronic mixer , i used 1 in a tug , but i fitted it separate to the rudder channel , so as i could selectively use it .
what i have done cheaply is put together a 4 micro sw , cam driven motor control , that i can stop or reverse seperate motors , tank steer , normally the 2 motors work together, 99% of the time .
when i need to , mainly due to wind , strong in the south ,i can independently control the 2 motors , to swing the model , to point it away from danger, man made islands , this would be less than 1 % of the time i use the model for , so it hardly justifies spending to much $$.
the motors i will "hide in ps rodney " will be low power versions ,555, to 50 mm props , which i hope to wire up for ONLY full power use , to increase stearage way .
as yet i have almost finnished the plan , but have not yet built the model , low spare time , due to job .
food for thought , regards bill s
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Hullo Bill...39 years ago I drove thru Mildura on our way to Adelaide...........but never to Renmark......but now I fly....... :terrific........
PS Rodney would be a fine vessel to model....has construction :hammer started? & if so at what scale?......following is an extract of page 125 from Parsons......... :clap
Derek :beer
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gday derek ,
seems i have the wroung bloke , sorry derek, im not good w names , getting old er LOL
my paddlers are built to 1/24 scale , penny is approx. 42 inch+16inch beam , not based on any vessel , rather a collection of photos
almost finnished ps gremma , but its a bit small , still sorting out trim ,have built hull for ranger+fitted paddle wheels , balsa+covered in f/glass .as i intend to build more of brewers paddlers , i will stick to 1/24 scale .
as you know , paddlers can do funny things ,i dont know what it is , but there is a connection to p wheel diam versus speed of hull , it seems to me , the bigger the diam. , the more thrust it will generate , but i dont know why ,also how does no. of floats work in to this ??
ps rodney , plan was generated from a lot of photos taken of Rodney Hobbs model at wentworth , hull was a educated guess , im still tossing around the correct draft , too shallow and it wont carry gear , too deep and it takes too much HP to drive hull, all my models are operational
paddle wheels are off the pevensey , brewers plastic kits , size approx. 1400mm loa+400? beam , hull balsa+f/glass, supers. , may-be 2 mm ply,w planking effect ,or HIPS, but its still in the planning stage , but im collecting parts and have built and painted the p wheels , i do not have a lot of spare time ,bill s
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Further to your discussions, have any of you checked out Ivor Bittle's website?
http://www.ivorbittle.co.uk/Articles/Paddle%20wheel/The%20paddle%20wheel%20design%20study%20for%20the%20internet.htm
An engineers solution to the problem
cheers
kiwi
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Hi PD's....& yes Kiwi.........we reviewed & discussed the paper by Mr Brittle some years ago.........& whilst it considers & explains very well the dynamics of feathering paddles..........to my understanding very few OZ paddlers were fitted with the same ......
From memory & according to "Parsons"..... PS Moolgewanke [ON31571] in the 1860's was the only paddler on our OZ waters with feathering wheels......... :shhh ...I always thought the vessel had an unfortunate name........ :nono.......Derek :whistle
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Hi Derek,
Was just asking as the question had been asked re rpm required, may have been a different thread, or maybe on MBH, (yes I know but its way, way past my bedtime and the senior moments are holding hands).
Am well aware re the Murray River paddlers and their power plans are configured, having spent some time on the river during my 25 years living in South Australia. And your right, as I do vaguelly remember that discussion.
Was just using that as an indication of paddle rpm, as I'm doing a similar exercise for models of our local stern wheelers from the 1860's and later, which did have feathering.
We must catch up sometime when next I'm in Sydney, as I often travel south while I'm there.
cheers
kiwi
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hello kiwi,
i think i read this a while ago , and i will enjoy reading it again , thanks , BUT
i tend to reley on experiences , so , again , i state , paddlers do funny things .
i had my paddle running beside a larger adelaide , w 14 floats per p wheel , and larger out-side diameter ,in 1/18 scale .
my paddler had a smaller hull (1100mm approx.to 1500 mm adelaide ) 8 floats and a scale smaller OD p wheel , yet the adelaide was by far quicker, easier driven ,and slower revs than mine , yet walked away from me .
it was clear from this that my paddle wheels would reach a max. speed , by going any quicker , all i did was create more bubbles, it did generate more thrust , but not very efficiently .
my observations on this day , the larger diam. wheels seemed to be more efficient , w 14 floats , i suspect the diam. of the p wheel was a big part in it , but i dont really know , paddlers are all different , and do funny things
regards bill s
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Hullo Bill & Kiwi....I agree paddle wheel dynamics are intriguing.....but we must be able to compare apples with apples
My float a boat plans for PS Adelaide were drawn as 1:24, however this did not provide sufficient calculated flotation for my engine & boiler so had the plans enlarged to 1:20
The new wheel size is 210 mm OD, the paddle blade wdith is 75 mm with a height of 18 mm & a 6mm 45 degree chamfer on the outer edge only, however with the hull at near correct waterline draft, effectively only three blades can be in the water at any one time
So each blade [75x18 = 1350 mm] - 18 for the 6mm triangle = 1332 sq mm per blade
Let’s also simplify the calculation & assume that three blades are doing equal work irrespective of their placement in the wheel [one digging in, one pushing & the last lifting]......
1332 x 3 = 3996 sq mm of blade surface area on each wheel = 7992 mm total surface area to propel the vessel
So 7992 sq mm of surface thrust x the RPM x the block co-efficient of the hull will determine vessel speed :porkies .......
I think this just highlights & confirms the points made below :squareone...but we also must remember that paddlers are not speed boats.....Derek :beer
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gday derek , thank you for a very interesting info on paddle wheel design ,thats my concern
i am wary of building some paddlers now , the oscar-w has a wide wheel , but small diam.,it is possible that the width of the wheel will help a lot ,but i have observed the difference in model performance between my paddler and Adelaide , mine has 3 floats in the water at any 1 time also ,although i suspect , not as deep as adelaide , due to the smaller diam.,130mm approx. .
when i first got the model wet , it was hopeless,hardly any thrust to drive model , so i lowered the paddle wheel shaft ,until the top of the floats were at least 5mm under the water line at rest , completely different vessel now .
we have a adelaide in w/bool in 1/24, same as my paddler , and it seems to run easier than mine ,i suspect the hull shape of mine isnt helping , rather bluff in the bow area .most on the Murrey paddlers had , long , tapering bows ,this seems to make the hull more slippery .
this is why i suspect that the diam. of the p wheel helps drive+the number of floats+what about the width of the floats ?? also the depth of the blades ??
a lot of theory , and questions , model versus full size regards bill s
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Bill...I also have the Australian drawn 1:24 plans for Oscar W
Just yell out if you could use detail the wheel diameter x width & blade height & approx. immersion depth etc.............I don't think I would be breaching copyright law :a102 .........Derek
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gday derek ,
thank you for the help and advise , i do have the plan as well , first i need to build the rodney , or rather get the spare time !! it will come , in time .
i have most of the details worked out +some mechanical parts .
i am also collecting bits for the adelaide in same scale +i have alum. paddle wheel rims cut out by laser cutter
i am wary of building a new model ,and suffering from lack of thrust ,hence the guarded concerns about p wheel diam.
regards bill s