Motors and ESC's

[Stu :)]

Right-o Hello everyone.

I've found myself in a bit of a pickle, to date I've been building and modifying plastic ship kitsets to RC. So far I've built a 1/350th Tamiya Musashi using servo and a simple three way switch, a 1/150th Trumpeter Zhong Shan using a FA260 with a circuit from a servo as a speed controller, 1/350th ICM Konig with 3x RF-020 servo motors and a modified servo circuit, 1/350th MHM Pola using a pair of 'Toy' motors (FA130's I me thinks) and a cheap park flyer ESC... which has been recovered far too often due to no reverse.

Now I've got a Revell 1/72 HMCS Snowberry to contend with, I've got it setup to run with a Tamiya TEU-101 ESC, with a 7.2v 2000mAh NiCd and a 45mm brass prop. What motor should I be running? The temporary motor from the bits box doesn't sound, nor smell good at half throttle.
It would be nice to have some speed, but not the kind of speed that would exceed the hull speed, nor do I want speed boat 'speed', I have a Vosper for that soon.

Also I'm a bit confused with something I've read regarding using capacitors on motors. I've always bridged the terminals with a ceramic cap, normally a 0.1µF, however it mentions that I should also- "The capacitors should be soldered from each motor terminal to the motor case"
Huh?!? Wouldn't that short out the power supply to the motor?

Many thanks,

Stu :)

[patmat2350]

nope, is alright. the caps don't pass any current through.

[Ghost 2501]

stu, for a 45mm prop, I would imagine a speed 600E 5-pole motor (or equivilent), you want torque NOT revs, so a 5 pole motor is best. Your temp motor is probably working its guts off and struggling.

for an esc, try a 25A one. I will check up for you on some corvettes, but My Sydney star has a speed 500E, 35mm prop and a 15A Viper15 esc for the main motor

the soldered capacitors for suppression, yes that is right, one across the terminals and one from the terminals to the can. and NO they dont short. to put it simple, what they do is divert the spark to make less arcing- of my models, only Espirit does not have the terminal to can capacitors

[LtDoc]

No recomendations for a motor, sorry. About the capacitors though. Capacitors will 'pass'/conduct DC for a very very short span of time, till the capacitor charges to it's 'capacity'. Then, no more DC going through it. That charge time is very short and the resulting 'path' to ground is for only fractions of a second, no real problem. For AC (which most interference is to start with) it's a different story. A capacitor will provide a path to ground for AC, meaning that it 'strips' the AC/interference from the DC before it gets to the motor, which is the whole point to using them. That's a very simplified explanation of how capacitors work, so don't take it for 'gospel'. But, it's 'close' enough to make sense to the average person not too familiar with all that electronic 'hocus-pocus' stuff. Hope that helps...
- 'Doc

[steveciambrone]

I have the same boat and propeller and use a Dumas 6v motor on six cells and it runs fine. Great slow speed performance and enough high speed to get it out of trouble if something arises.

The flower class builds into a fine ship model and takes to R/C just great. Keep the internal weight low, ballast it to the water line and it will have fine handling qualities.

There were several threads on the build so you may want to do a search and review them.

Thanks
Steve

[Ghost 2501]

if I recall, the flowerclass 'vette is one of the most popular kits available

[pkboo]

Stu, I believe U'r a little bit underpowered for those props. Let's see U'r boat is about 30", water has some serious resistance and U'r using way to big a prop for that size of ship (Ghost!). Go back to a 35mm or even try a 30mm, three bladed, regular prop (check www.raboesch.com), use a 400 type motor geared 1:2 (you'll get about 5,000-6,000rpm on the prop) and an 25/30A ESC (just to be in case if you need a higher rev motor). I bet you'll get the speed you want and need!

I got a Lindy fletcher which I'm powering with a 400 graupner driving (1:2.5) two 30mm three bladed working (wide blades) props, dry tests look good. I'm probably starting a thread next summer. Good luck --> Eugène

[Ghost 2501]

pkboo, i think Stu's model the 1/72 corvette, which probably has a stocl 45mm scale prop if i remembere the kit, i know the prop was BIGGER than the kit prop supplied with my sydney star model

[pkboo]

Ghost, than you might be right that he would need a 500/550 type motor. Still at models you never know, the motto is test and test again especially with propsize. No doubt though that he's using to small a motor.

[Kaskazi]

The following will probably interest you - might even be helpful :D
http://members.shaw.ca/modelflags/tips/flower.html
http://www.cbrnp.com/RNP/Flower/MODELS/Lessons_learned.htm
http://www.cbrnp.com/RNP/Flower/MODELS/Revell_Flower_inbox/Revell_Flower_inbox.htm
http://www.cbrnp.com/RNP/Flower/REVIEWS/GLS_Sirmar/GLS_Sirmar.htm

[pkboo]

Way to go Kaskazi! :)

[Stu :)]

Thanks for all your help. Yes the temporary motor was too small and over powered (it seized up on a bath trail), so it's off with me to the hobby store on the other side of the city tomorrow for a 500 or maybe a 540, the guy on the phone said a 540 maybe a better setup.

Stu :)

[Ghost 2501]

try a 545 type. Its the same can size and fittings, but has 5 poles not 3, giving lower draw and longer run times. its also less revvy. the 3-pole 540 type are quite revvy.

[Stu :)]

Well the local hobby store recommended a Tamiya Super Stock TZ motor, it didn't seem right so I when to other hobby and they to made the same recommendation, so I drove half an hour across town to hobby store with a model boat person in the store, rather than a RC car or plane staff. You know what? He said the same darn thing Tamiya Super Stock TZ motor. So now have one.

One more thing, does this motor need to be run in? I've tried a 3x and 4x D cells, but the motor does not turn, the only other idea is to hook it up to the boat without the prop and leave it with the transmitter trim at 3/4 throttle.

Stu :)

[Rex R]

before you go any farther with running the motor, check to see if there are any mounting screws interfering with the rotor(the screws are sized for use with a mount and if screwed all the way in, can cause the motor to act like is siezed). hmm think I would have gone for a 27t motor... run in; well there are prolly more ways to do this than smiths in the phonebook... easiest is to apply a small drop of oil to each bushing/bearing, install the thing in the ship and simply run the thing at half throttle for the 1st pack or two(in other words, just run it like you intend to) after a couple of runs the motor should be fine.

[redboat219]

How about posting some pics of your conversion projects.

Red

[Skip 1940]

Hi Stu, if would explain how to attach a photo, I`d gladly show you my powertrain setup in the Revell / Monogram Flower Class Corvette. Iv`e since made an adjustable motor mount so that motors can be swapped out in less than 5 minutes using no screws nor bolts. I sure could used that setup in this boat with all the motors I experimented with! Skip

[Umi_Ryuzuki]

Hi Stu, if would explain how to attach a photo, I`d gladly show you the powertrain in my Snowberry. Skip

Try these threads... ;)

http://www.rcgroups.com/forums/showthread.php?t=610209
http://www.rcgroups.com/forums/showthread.php?t=545544

[Stu :)]

I'll post some pictures of the Snowberry and Zhong Shan soon as the digital camera is charged. I've sold the Pola because I was sick wading out into the pond to retrive it (park flyer ESC and shallows) and the Konig as I wasn't happy with the drive train I had installed. However not to worry the funds were used to help pay for a 1/24 Torpedo Boat. There's a water damaged Konig going for half price at the local hobby store, only thing wrong with is the box, instructions and decals are ruined. However I have all that from the first Konig, so if I don't hit the 'plastic' too hard at the Roger Waters concert tomorrow night, I'll grab it. This time around I'll use a single motor direct driving one prop, but retain two rudders. I'll cheat on this one and DIY a speed controller and use two Li-ion batteries I pulled from a laptop battery pack.

What really bugs me is why no one has made a inexpensive park flyer like ESC that can do reverse! Surely it can't be that hard?... is it??? I can just imagine so many plastic ship kitsets coming to life on a pond near you. Maybe I should fix my chip programmer, there might be a market here.

Stu :)

[Umi_Ryuzuki]

...
...

What really bugs me is why no one has made a inexpensive park flyer like ESC that can do reverse! Surely it can't be that hard?... is it???

...

Stu :)


Usually BAD things happen when aircraft propellers run in reverse. ;)

[LtDoc]

...:) Making the prop work backwards is the only way I know for a plane to back it's self up. Unless it has more than one engine, and they are located further out on the wing than the main gear. Sounds silly, but it do work.
- 'Doc

[Stu :)]

What I was trying to say is; I wish they (being the makers of RC components) could make small and cheap ESCs like they do for park flyers, but also with a reverse option.

Usually BAD things happen when aircraft propellers run in reverse. ;)

Been there done that in a real aircraft whilst learning to fly, on a simulated engine failed approach I didn't realize that the aircraft had been modified for alpine airfields; meaning short runways. The prop was still ticking over and I thought it wasn't 'real' enough so I pulled the throttle right back and had brief lesson at 500 feet in what happens when the theory of lift goes wrong :eek:

Stu :)

[LtDoc]

...what I hate most about that sort of stuff is the cleaning bill.
- 'Doc

[Stu :)]

What really bugs me is why no one has made a inexpensive park flyer like ESC that can do reverse! Surely it can't be that hard?...

The heavens parted and the sun did shine on the back page of Model Boats 100-page Kit Special and a cry from the bottom of the world came... hallelu- :censored: -jah...

The Mtroniks Viper Micro Marine
26mm x 25.6mm x 9mm - 15grams - 4.8-12volts - 10Amp - BEC - Waterproof...

Right where's the credit card?

Stu :)