Model Boat Mayhem
Technical, Techniques, Hints, and Tips => DC Motors (Brushed) and Speed Controllers => Topic started by: ajb68 on August 27, 2009, 03:34:05 pm
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DOES ANYBODY KNOW THE RPM OF A 6 VOLT DECAPERM AND IF IT WOULD BE SUITABLE FOR A 33 " FISHING BOAT WITH A 3 " 4 BLADED PROP ? CHEERS GUYS , ANDY
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No, but it would be suitable. :-))
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Ive got a 6 volt Decaperm in a "danny boy" with a 2" prop and it very nearly planes !
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I can't answer the revs question, but I've got one of these in the attic - and I've just seen the price of a new one!!!!! :o
How did that happen?
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They aint cheap thats why i wanted to be fairly certain it would be ok for what i need :-) after i recover from the expense i will start on the build O0
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Deccaperms, 6 and 12 volt run about 2750 rpm at the geared outlet shaft.
Bob
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cheers bob :-) should do the job nicely :}
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ajb68,
If you don't have DECCAPERMS the 550 geared motors sold by Model Slipway or a 550 on a 2:1 reduction gearbox will be a better and cheaper solution.
Bob
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in what way are they better ? i thought decaperms were top notch motors , but then i dont know much about motors , {:-{
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Deccaperms are large motors geared down to give the torque.
They are electrically very "dirty".
And very expensive.
The geared 550 is relatively cheaper and gives you the option of using 6 or 12 volts, (or any in between), on the same motor so far more flexible.
These motors pull about 1 amp in air and only 2 (aprox) in use so less power hungry.
These give similar torque.
In the event of a burn out just replace a 550 motor, yes Deccaperms do have problems too.
If I buy a boat with Deccaperms in it I usually sell them and replace with Geared 550's.
Some people swear by them, I swear at them!!!
Bob
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Bob is right, Decaperms are old fashioned and overpriced. A modern motor will do a better job at a much lower price.
They were the business once - back in the 1970s!
Colin
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would a geared 550 run a 3 " 4 blade prop ? {:-{
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Up to about a 3 inch diameter, My own tug has this set up.
Bob
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Or if you want a bigger prop go for the 3:1 reduction. Or even to slow the output speed down.
What model are you wanting it for and what size prop?
Bob
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would a geared 550 run a 3 " 4 blade prop ? {:-{
A motor or geared motor can run a prop if the torque load of the propellor is less than half the motor stall torque.
If you have a large prop,don't concern yourself or get confused with any other data or number of poles or high drain/low drain
RS775 (http://banebots.com/pc/MOTOR-BRUSH/M5-RS775-12) STALL TORQUE 431 mNm on 12 v
Torpedo 800 (http://www.shopwiki.co.uk/_Torpedo+800+Motor) STALL TORQUE 480 mNm on 12 v
Graupner speed 900bb (http://www.cornwallmodelboats.co.uk/acatalog/graupner_6373.html) STALL TORQUE 1000 mNm on 12 v
Graupner Speed 720BB Torque (http://www.cornwallmodelboats.co.uk/acatalog/graupner_6372.html) STALL TORQUE dunno but large on 12 v
What Bob says about the 550 is true going by the data.
It is more of a 6 volt motor while the data here (http://banebots.com/pc/MOTOR-BRUSH/M2-RS550-120)is at 12 volts.
My pick would be a 775 on 12 volt.
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I have a fishing boat 28" long,running on a 2" 4 blade prop on a maplins mfa motor with 2.1 gearbox,
good turn of speed and motor barely gets warm
Hope that helps
Mark
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Or if you want a bigger prop go for the 3:1 reduction. Or even to slow the output speed down.
What model are you wanting it for and what size prop?
Bob
Its for a cygnus sf 33 from models by design the prop will be 3 " 4 blade
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Scratch the 775,800 or decaperm idea.
Graupner speed 900bb or air conditioning blower motor out a scrapped car.
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Or one of my 900 motors will power it no problems....... :-)) :-)) :-))
http://www.modelboatmayhem.co.uk/forum/index.php?topic=19292.0
Mark.
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i run robbe navys 540 geared 5:1 on 12volt turning a 4inch prop 6mm shaft ''no problems'' in my tug with the cost of decaperms you could but 2 navys & still have change left O0 (you could take the other 'half out for lunch on the change :-)) :D
as it happens i to am building a 33inch gm33 (can you guess the motor thats in it ;)) a 70mm prop for this one!!!
regards ray
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I am running a 26 year old Decaperm in a model 54" long with a 4 blade, 80mm.propeller. I can sail all day on a 6Volt - 8Ah battery and to judge by the time it takes to recharge the battery after each session the motor cannot be drawing much more than 0.5Amp.
I have no experience of any other motors but I'm happy with the Decaperm.
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The way to measure current is with an ammeter.
It will debunk your conclusion,Tankerman. %)
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Or if you want a bigger prop go for the 3:1 reduction. Or even to slow the output speed down.
What model are you wanting it for and what size prop?
Bob
iTS FOR A MODELS BY DESIGN CYGNUS SF 33 1/12 SCALE , WILL BE USING A 3 " 4 BLADE PROP ,
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Can you picture the prop reaching the rpm on the decaperm box?
Deccaperms, 6 and 12 volt run about 2750 rpm at the geared outlet shaft.
Bob
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ajb68,
Look at the MMB 900 motor on here in the traders section.
It will be direct drive and on 12 volts will push her along nicely.
The price of a Deccaperm will pay for the motor, coupling and ESC.
http://www.modelboatmayhem.co.uk/forum/index.php?topic=19292.0
Bob
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i run robbe navys 540 geared 5:1 on 12volt turning a 4inch prop 6mm shaft ''no problems'' in my tug with the cost of decaperms you could but 2 navys & still have change left O0 (you could take the other 'half out for lunch on the change :-)) :D
as it happens i to am building a 33inch gm33 (can you guess the motor thats in it ;)) a 70mm prop for this one!!!
regards ray
Have you got any pictures of your latest build Ray ?
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Decaperms are a very SOFT motor, with being made of plastic, which is why you should only run them geared. If you overload them for a short time the plastic softens, the pins start to cut through the endcap & then Kaput. £££££££££££down the drain. When I was at work I used to reclaim
them by making new endcaps But when I worked out the cost it was cheaper to buy another motor.
Haviing said all that, they used them in the 100 watt class, ungeared, but only running for a very short time. Stick with the advice of the others,
Nemesis
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hi andy sorry i havernt taken any of this one ''in stages'' yet but all the running gear is in prop shaft rudder etc the deck is all in the frames/ ribs are in as well nexted up is the teak gunwhale's :-)) regards ray
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did you get the full kit Ray ? ive gone for the sf 33 with a stern wheelhouse , should be here next week :-)
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Hi guys
Can only agree to some contributions above: Deca was a "Mercedes" --- 25 years ago.
And is an old overpriced grandfather...
For myself, long time I prefered van motors from the junkyard.
(Nowadays it's not easy to get a cheap one there...)
In meantime i'm using industrial Buehler motors. Some shootings at ebay, and some bought here:
http://www.hobby-lobby-modellbau.com/onlineshop/product_info.php/info/p2893_B-hler-BB-Power-f-r-Gro-modelle--12-Volt.html/XTCsid/0b9b671ebfee2024dd501a9a6ed612bb
If you have enough mounting space and ballast of ~700gr : First choice!
No gear, no noise, 12pole-collector, 3300rpm. @12V (IMHO: 35W netto, 50W max)
Starts softly at ~3V/250 mA.
I'm using them in 2 ships, each with 2x 24V-types. and 70mm/75mm Raboesch props.
Each about ~65" and ~32 kg.
No heating, no problems. Current (combined, both motors) : Full throttle ~3A, if ship is fixed: ~4A
I think, this motor could easily drive your 3"4 blade. And 3300rpm is much enough for such a monster-blade ;-)
Pete
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Would appreciate it if you motor gurus looked at my enquiry in the warships forum titled "RAF Range safety Launch" drive queries.
thanks
Ray
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If you overload them for a short time the plastic softens, the pins start to cut through the endcap
When you overload anything it will fail. Why were you trying to run a motor in a way that it was not designd to be used :o
Used correctly the Marx Luder motors are still some of the best motors arround. I have models 30 years old with them and they still run extremely well as they did when new.
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:-))
Thanks . for the information.
Ray
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hi, i have a maggie m kit to build, and i would like to over power it as im going to try and tow a trawl with it. whats the most powerfull motor i can run in her, i was thinking of not using the kort and going for the largest five blader prop i can swing, cheers mike.
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hi mike k i had a maggie m that had a working trawl winch the motor i had in was a small 12 volt 'bosch'car heater fan driving a 50mm 4blade prop this was plenty of power for her!! the trouble is mike if you get snaged on the bottom with you trawl &give it to much power she will roll over mine allmosed did! i would fit a 540 geared 2;1 or 3;1 & keep the nozzel on you dont need a speed boat to go trawling!! i have another boat that trawls this has a 540 geared 3;1 on 6volt 'it works fine' regards ray
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hi ray, i have got a como drill 6 to 1 geared motor that came with the kit that should do then, best get my waders sorted for when i have a go up and down the beach. the cygnus looks good towing there, thanks mike.
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hi mike that would be a better set up for the maggie so where are you going trawling?? regards ray
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Or one of my 900 motors will power it no problems....... :-)) :-)) :-))
http://www.modelboatmayhem.co.uk/forum/index.php?topic=19292.0
Mark.
hey mark do you only sell 900's??
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I also sell 755 motors and 555 motors
MMB 755 5 POLE MOTOR
6-12 VOLTS
NO LOAD SPEED 4400RPM ON 12 VOLTS
NO LOAD CURRENT 0.3 AMPS
LENGTH 87mm
DIAMETER 42mm
SHAFT DIAMETER 5mm
look under www. marksmodelbits.com
Mark.
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cheers mate had just found the website when this acme thru\!!
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Hi, Keep your Kort as you get more thrust at slow speed which is why inshore trawlers use them.
Nemesis
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thanks i will stick with the kort then, i would like to try a spot of rock hopping in mullion harbour but she wont be ready for my holiday. i will have to stick to goodrington beach in torbay and make sure i have my waders with me.