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e-E-Flite Blade CP mCX CX 400-3D > "Llama Mods" Motor Mix Tech notes
 
 
nat3cpu
Heliman
Location: North Liberty Iowa

Aight, call me crazy, insane, over confident or just too imaginative....
I'm guna do it, this thread is dedicated to the CUSTOM design and creation of a method by which to use the STOCK 4-in-1 with brushless motors. I do have 3 requests for this particular thread, and would REALLY apreciate people following them as it would lead to faster development of this concept.

1. This thread is for posting required technical information which is needed to acomplish this mod.
2. This thread is for posting required design concepts and plans which are needed to acomplish this mod.
3. I would rather comments on this mod pe posted in the following "Llama Mods" Motor Mix Comments thread.

I am positive this CAN be done, I have contacts in a lot of places and have plenty of strings I can pull to get this from a finished conceptual design to a working prototype, and yes, that would include using SMT (surface Mounting Technology) electical parts similarly used in micro-circuts.... Lets do this, I'm feel creative and optimistic and hope this doesnt blow up as impressivly as some of my projects! LETS DO THIS!!!

Life isn't fair.. Luckly it's a game and cereal!
09-08-2005 Over year old.
 
 
nat3cpu
Heliman
Location: North Liberty Iowa

The Concepts basics

Alright, here goes. Now that I understand the basic concept of the brushless motor, the actual RPM governing component, I feel we can design a stand alone, CHEAPER, and more flexable solution to bring a brushless ESC to a standard brushed motor ESC controller.

Here are the main keys of this design and its primary design goals.
1. The ESC must use a portion of the brushed motor controller's power to govern the start-up and shut-down of the brushless motor, I'll go more in depth on how this switch could work in the near future.
2. The ESC must let the brushless motor come up to a set RPM range, and still be able to cut all brushless motor power to prevent damage during a crash.
3. (Hopefully) will not require the use of a actual logic chip. How I will get into shortly.

To achive these goals there are going to be specific and realativly accurate measurements to insure that this thing doesnt spew smoke flame and ash....

1. The required RPM's for a 9 and 10 tooth main motor to spin at to obtain a main rotor rate of 2,200 <=2,000 (between 2,200 and 2,000)

This measurement is going to be the basis for all design and development steps from here on out. Once we have this ratio, we can select a Brushless motor that can fulfill these RPM specs with the lest power consumption (A motor that isnt over or under powered for the RPM range we need)
I look forward to this challenging and complex task, I know as a community of RC Heli guru's we can get it done!

Life isn't fair.. Luckly it's a game and cereal!
09-08-2005 Over year old.
 
 
nat3cpu
Heliman
Location: North Liberty Iowa

Other key design component

Aight, as I said earlier, I'm guna now cover how we may be able to govern the actual turning on and off of the brushless motor.

The key to this section of the device is to insure that the 4-in-1 doesnt get fried, in other words, we can NOT pull all required power from the 4-in-1's brushless motor power output. I'm sure pushing 10+ Amps through that circut could do some very impresive smoke output and very little else. Soooo here goes the crazy stuff....

To provide power to the motor and this make shift controller, we will need to pull the power off of the direct inflow from the battery at the 4-in-1. We should be able to simply splice a ' y ' adapter to pull the power before it hits the 4-in-1

Alright, with the power source problem addressed, we can now cover the actual activation of the circuts (Controlling when the motor actualy gets power and when it doesnt...).

Now to accelerate the brushless we can simply incease the power being sent to it, not that complicated. Using this as a 'on/off' switch should be fairly simple. Heres the concept. Lets assume that the brushless motor takes 0 through 11.1 volts. Now, by simply requiring the input to this brushless ESC from the 4-in-1 to hit a specified level (say a minimum of 6 volts), the motor will start getting juice and will continue to get more as required based simply on how much additional voltage in coming into the ESC.

Heres how we will do this.

Transistors work by keeping a circut shut untill a specific level of voltage on one of the 2 inputs is reached. The + voltage that we have split off of the ' y ' adapter is to go into one of the 2 inputs on the transistor, and the brushed motor + voltage is to go to the other input on the transistor. By doing this the rest of the ESC is not given power untill the transistor is turned on by the brushed motor + voltage hits its specific level, at which point the transistor turns on and the straight battery power is allowed to flow through the now turned on transistor.

here is a VERY rough keyed picture of what this would kinda be like....

(=) is the battery

\
> is the transistor
/

(4) is the 4-in-one

(C) is the rest of the ESC concept design

(=)
\
> (C)
/
(4)

once the + voltage of the (4) increases to the pre-determined level, the transistor will complete the circut between the (=) and the (C) and the (C) is able to provided the required power to run the rest of the ESC and motor without frying out the (4)

WHEW! Alrighty.....if you have any questions about this or comments on any of this, PLEASE PLEASE PLEASE make comments in the comment section, even if its "cool idea, dunno if it will work, your a psycho, but cool idea!" post it! encouragement is what tells me that this is a mod that people would like to see done. Also, if you have any of the required electical skills required to actualy design and spec out any of the required components of this mod, PLEASE PLEASE PLEASE say so in the comment section so we can get in touch and see whats guna be required to pull this off... I'm conffident we can get this done, hell, with this simple circut we may be able to simply put a regular ESC on the (C) section of this and keep it even simpler... who knows!

Life isn't fair.. Luckly it's a game and cereal!
09-09-2005 Over year old.
 
 
JJGONZO
Senior Heliman
Location: Aliso Vuejo, California

Cool idea dude!

Keep working at it.


Believe it until you see it.

Ah! here's a pic of my bird.



09-09-2005 Over year old.
 
 
stealth916
Veteran
Location: Rocklin, CA

I don't think you are going to be able to control the timing of a brushless motor using techniques you have outlined.

What you are describing would like to be accomplished by ANYONE with a box full of bushed motor controllers facing down the prospect of trashing them or selling them for $5 a pop after paying $80 a pop for them... So don't get me wrong - plenty of people would like it - but you'd think if it was easy, doable & economical for the novice, or with any sort of low parts count - it would have also been done commercially by now...

If you are serious about this project - you should show it by taking it out of this forum and to a motor and controller designers forum....

What you are trying to do has ramifications far outside the world of RC - so you really owe it to yourself to collaborate with people who are experienced in motor and controller design, plus the concepts behind brushless motors.

Best of luck
09-09-2005 Over year old.
 
 
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e-E-Flite Blade CP mCX CX 400-3D > "Llama Mods" Motor Mix Tech notes
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