Discussion WTC Piston Tanks/Motors

[jaguar75]

Piranha piston tank motor is not centered enough to fit inside the wtc pipe diameter.The piston tank will be the same outside diameter as the polycarb pipe.

[jaguar75]

Originally Posted by Albion

Clearly you dont have everything, cos it does exist, Hello Moto speaks the truth. Think they only appeared this year.

Check out the ones which end "380 custom"

ok higher current drain, but it s not like it is running all the time


Also you could consider these guys
http://www.piranha-modellbau.de/Tauc...tubeKolben.htm

Sorry,no chance with that!the motor is out of the tank circumference.
I have been sourcing the information for a time and I will have to make my own diving piston tank.

[jaguar75]

This 380 motor piston tank would fit inside the 3.50" I.D. wtc polycarb pipe,since the tank with the outboard measurement of the circumference is 3.05".
The problem is that I need two-1000ml tanks and they recommend only going up to 600ml each tank.
Too bad that Engel does not offer the motors in TeamNovak brushless motors.They are more power than a brushed 540 but the size of a 380.

[Sub culture]

If you don't have a copy of 'Model Submarine Technology' By Norbert Bruggen, from Traplet, then I strongly recommend getting one.

It deals extensively with ballast systems, and has a whole chapter on piston tank design. Although no designs/plans for a tank are shown, it does deal with calculations and formulae for deciding on the motor required, and gearing to suit.

[Skip Asay]

"So what driving torqe in lbs.-inch do you need to drive a 3.5" piston?"

If I remember my high school math correctly, the surface area of a 3 1/2" circle is 9 1/2 square inches. Keeping it simple, at say, enough depth to equal 1lb. per sq. inch, that would be 9 1/2 pounds of pressure to be overcome.

"What is the rod's thread count per inch,which has something to do with the torqe and speed ?"

If you used 1/4 - 28 threaded rod, that's 28 revolutions per inch which means a whole whopping 28 RPM of the motor per inch of travel. You'll need a really huge motor for that, don't you think? And let's not forget that, while a motor puts out it's most power at stall, it also draws the most current at stall.

"It is strange how you and others are saying that a brushed motor,belt-drive gear-reduction system,RF motor resisters,BEC,ESC are so much less expensive than a brushless motor/ESC combo that has those options but does not require any gear-reduction.The brushless motor/ESC combo is only $150.00,uses less battery current,has low scale speed control,instant forward/reverse,makes much less noise,is easily disassembled for serving and upgrading."

I could do the whole thing with brushed motor, gear reduction (not toothed belt), no BEC required for this, servo amplifier with no ESC, for under $100.

"I take it that you also sell brushed motors and parts?"

No, you're completely wrong. While I did own SubTech for 13 years, I sold that close to 5 years ago which means that I have no vested interest in whatever you use.

It seems very much as though you've got a burr under your saddle because we're not all in agreement with you. Have you taken the time to consider that maybe, just maybe, we're trying to HELP YOU? Speaking for myself, I've been doing this for over 35 years and, to the best of my knowledge, Subculture has 20+ years behind him. That's well over 50 years experience and that's just the 2 of us. I know that when I started, brushless wasn't available, if you wanted an electronic speed control, you had to build it, if you wanted an electronic switch, you had to build it, and the list goes on. So I learned the hard way which amounted to making a whole bunch of mistakes. I would have given anything to have what you have now - the ability to reach out and receive help from a whole bunch of folks who've been there and done that. So I suggest you back off a bit. You seem like the guy who's drowning but slapping away the hand that's being offered.

Skip Asay

[Skip Asay]

"Skip and Subculture,
Have you guys used the Norbert Bruggen/Engel piston tanks in your subs ?"

I've made my own including a proportional control system. I've also built one that is similar to what you're doing in that the OD of the WTC is the same as the OD of the ballast tank and I had no problem with the motor extending past the ID of the WTC.

Skip Asay

[jaguar75]

If I remember my high school math correctly, the surface area of a 3 1/2" circle is 9 1/2 square inches. Keeping it simple, at say, enough depth to equal 1lb. per sq. inch, that would be 9 1/2 pounds of pressure to be overcome.

If you used 1/4 - 28 threaded rod, that's 28 revolutions per inch which means a whole whopping 28 RPM of the motor per inch of travel. You'll need a really huge motor for that, don't you think? And let's not forget that, while a motor puts out it's most power at stall, it also draws the most current at stall.
A Halls sensored brushless motor does not stall and has more than enough power to drive the shaft.The hollow shaft motor that I am using also communicates the position with memory and speed to the encoder board.Have you used this motor?I could do the whole thing with brushed motor, gear reduction (not toothed belt), no BEC required for this, servo amplifier with no ESC, for under $100.00.
Anything other than belt-drive is toy-like and noisey.Using a belt-drive system gets the price up to the brushless motor/ESC price($150.00).
No, you're completely wrong. While I did own SubTech for 13 years, I sold that close to 5 years ago which means that I have no vested interest in whatever you use.
You seem to be promoting the use of the status quo regardless of what you are saying.You were by design rocking the improvement boat by creating your own improvements to the rc sub components but are telling me to stick with what you did?!It seems very much as though you've got a burr under your saddle because we're not all in agreement with you. Have you taken the time to consider that maybe, just maybe, we're trying to HELP YOU? Speaking for myself, I've been doing this for over 35 years and, to the best of my knowledge, Subculture has 20+ years behind him. That's well over 50 years experience and that's just the 2 of us. I know that when I started, brushless wasn't available, if you wanted an electronic speed control, you had to build it, if you wanted an electronic switch, you had to build it, and the list goes on. So I learned the hard way which amounted to making a whole bunch of mistakes. I would have given anything to have what you have now - the ability to reach out and receive help from a whole bunch of folks who've been there and done that. So I suggest you back off a bit. You seem like the guy who's drowning but slapping away the hand that's being offered.

Skip Asay[/quote]
You are telling me that you want to help me by holding back innovation?!!!
You have said the same things about brushless motors and any upgrading of components for modern tried and true methods.Have you used the same brushless motors that I am using?The threads are a mile long by now with your raving about keep it just like the old ways,because it works for me and don't change a thing.This is very frustrating to anyone trying to make things change for the better.Not all of the sub designers here are on a shoe-string budget and can afford to innovate with more expensive parts and are in it for the advancement of the rc submarine.My rc sailboat has been with me for over 20 years and I hope to have my sub longer than that and am not doing this for resale.

[Skip Asay]

"A Halls sensored brushless motor does not stall and has more than enough power to drive the shaft.The hollow shaft motor that I am using also communicates the position with memory and speed to the encoder board.Have you used this motor?"

No, I have not. Let me know how it works.

"Anything other than belt-drive is toy-like and noisey.Using a belt-drive system gets the price up to the brushless motor/ESC price($150.00)."

I'll certainly disagree with both of those statements but, let's leave it at that.

"You seem to be promoting the use of the status quo regardless of what you are saying.You were by design rocking the improvement boat by creating your own improvements to the rc sub components but are telling me to stick with what you did?!"

Based on your posts, you seem to be somewhat of a "newbie". With that in mind, I'm a firm believer in first, you crawl, then you walk, and then, you run. You seem to be bypassing a step or two.

But the long answer is that a brushless motor is still an electric motor. It's laid out a little differently which does make it more efficient than a brushed version, but it's still an electric motor. And getting full power with sufficient energy to do what you want it to do and still be efficient in terms of current draw seems kinda out of reach.

"You are telling me that you want to help me by holding back innovation?!!!"

Not even hardly. I applaud your attempts, but I believe I see you going down the wrong path so I'm offering help to get you back. That's all.

"The threads are a mile long by now with your raving about keep it just like the old ways,because it works for me and don't change a thing."

Boy, have you been reading things the wrong way! If you're referring to my exchanges with aqua-something, then you haven't been reading them at all but rather seeing what you want to see or expect to see. That you're wrong in that goes without saying.

"This is very frustrating to anyone trying to make things change for the better."

I'm sorry you feel that way but if you took the time to see exactly what's being said and not what you THINK is being said, things would certainly go much easier for you.

Change for the better is a good thing. Change for the sake of change is not. Change based on misconception or misunderstanding is even worse.

Skip Asay

[Sub culture]

John,

You do tend to be somewhat abrasive in your replies to other folks postings. No one here is telling you to do things a different way, we're just pointing out alternatives and highlighting that you are taking a long and winding road. Will you stay the course?

By all means experiment, but these are areas where few have ventured, so you will find it difficult to obtain feedback on your proposals. Probably CNC groups would be a better place to discuss brushless DC servo systems.

At the same time, when you make public postings, it's important to realise that not everyone has engineering experience, but they may like to use a certain ballast system in their boats. For them I think it's important that they are aware that a brushless system is far from essential.

[jaguar75]

Quote : Sub culture
For them I think it's important that they are aware that a brushless system is far from essential.
Do the math.
Just because YOU love brushed motors does not mean that you can speak for everyone else building here.
You are stating that brushless motors are far from essential.
Well,I guess a person could say the same for brushed motors,as well.
The fact is that the prices are so close to the complete brushed systems versus brushless systems but that is comparing quality parts with quality parts.This means a belt-drive gear-reduction system ,as well.Without this ,you have RF noise,not to mention audible noise.The brushless motor for my prop is direct-drive beacuse it is speed controlled with Halls sensors.
Brushless motors create less RF interference by making less noise,they cool better because the windings are next to the aluminum can and not on the armature.There are no brushes,which equates to much less friction and heat.A brushless motor is smaller and lighter than it's equivilant brushed motor replacement,infinitely rebuildable and upgradable.

[Sub culture]

Oh well, it seems I've been doing it wrong all these years, therefore you'll require no more help or advice from me. Crack on!

[jaguar75]

I guess that I have been laboring under a false apprehension that it was a free and innovating world on the rc forums and not a place to just go with the status quo.
Hobbyists live in a free world now,even Russia has the freedom of choice.

[HelloMoto]

Originally Posted by jaguar75

I guess that I have been laboring under a false apprehension that it was a free and innovating world on the rc forums and not a place to just go with the status quo.
Hobbyists live in a free world now,even Russia has the freedom of choice.

Huh? Your free to build anything you want. Just because others think your ideas are pants and hence cant offer the guidence you are looking for doesn't mean you are not free to do it your own way. No one has made or used what you are proposing, so you will need to go build it yourself and tell everyone how it turns out.
I am all for making improvements and moving forward. Personally I cant see any benifit in what your proposing, different yes, but better? Untill you build and show what improvements you've made over the "status quo", I am not sold. So far all your 'ideas' seem complicated , harder to build and offer no tangible or worthwhile improvement.

[Skip Asay]

"Just because YOU love brushed motors does not mean that you can speak for everyone else building here."

It's really not a matter of "love", but rather one of cost, reliability, KNOWLEDGE, and more. The FACTS are that brushed motors do work well, are easily obtainable, and don't require special speed controls.

"You are stating that brushless motors are far from essential."

And I agree. Hey guys, we're not building racing boats here. If we were, I would say that brushless is imperative. But we're not, are we?

"The fact is that the prices are so close to the complete brushed systems versus brushless systems but that is comparing quality parts with quality parts.This means a belt-drive gear-reduction system ,as well.Without this, you have RF noise,not to mention audible noise."

Again, I beg to differ. While the really low end brushed motors can be considered "dirty", the overwhelming majority just require 3 caps at less than a buck and they're clean as a whistle. I've seen brushless motors causing interference, though.

"The brushless motor for my prop is direct-drive beacuse it is speed controlled with Halls sensors."

The speed control is nice but for max EFFICIENCY a reduction is suggested. Just because a motor can spin a prop doesn't automatically make it efficient.

"Brushless motors create less RF interference by making less noise,they cool better because the windings are next to the aluminum can and not on the armature."

As far as RFI is concerned, see above. As far as heat is concerned, if heat is a problem, then you're working the motor too hard which, again, suggests a reduction.

"There are no brushes,which equates to much less friction and heat.A brushless motor is smaller and lighter than it's equivilant brushed motor replacement,infinitely rebuildable and upgradable."

The main reason I haven't gone brushless is that I don't see the need. I've put a lot of time and effort into increasing the overall EFFICIENCY of my boats which means long run times between charges. My Type XXIII (scratch built, 56" long, spinning a 2 3/4" 3 bladed prop which was originally designed for a steam powered boat which means it's got a fairly steep pitch) will run for over 2 1/2 hours with 2700mAh NimH batteries. That means I'm only drawing ONE AMP! Why should I waste the time and money to go brushless?

If brushless is your thing, then go for it. But don't tell me it's the "wave of the future" or anything approaching being the "best" way to go.

Skip Asay

[Aeroengineer1]

I have to say that you guys do get a bit moody now and again. If this guy was Michael Himzy (man it has been a long time since I have heard from him) I could understand having misgivings, but he seems so far to have presented a desire to do something that while different seems plausible, and fulfills his desire to build functional models. If he has the knowledge to pull this off (we should wait and see), I think that it would be pretty slick. I am sure that the motors that he has spec'ed out are going to be large enough to work for any piston tank in the size that he is looking to do. We need to remember that electric motors provide full torque at zero rpm (yes I do know that current draw can be high). Needless to say, I say that we give him some breathing room and see what he comes up with.

Adam