arpitman
Posts: 88
Joined: 12/25/2003
From: Layton,
UT, USA
Status: offline
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I have had my Blade CP for about a month. I love it! I mainly have been flying planes. I had a gas Heli a long time ago, but didn't get much beyond hover before giving up on it. I saw a used Blade for sale for $200 without knowing you could buy them new for $220. I bought the used one thinking it was a steal and fixed the broken parts. I was amazed at how cheap it was to fix after each crash (yes I crashed a lot at first).
I am now flying pretty good. I don't crash as much and am enjoying....
Now to the reason for the posting, brushless conversion. I was very bummed when I first realized that the 4 in 1 seemed to preclude the possibility of adding a brushless. Having flown planes I have learned the great benefits of brushless for planes. I figure the same features will come to Heli if I could only do it.
I don't have the money for a new radio with Heli mixing and all the stuff that would be needed to convert the Blade to new electronics. I am a software developer who works with electronic hardware engineers and turned to one of them to help. We came up with a plan to build a small module that would convert the brushed motor output to servo input that could be used to drive a brushless ESC. During the pre-development stage of this I discovered something about the 4 in 1 controller.
WARNING: following from here and doing what I did will for sure void the warranty of your 4 in 1 controller. Don't do it if you ever hope the make a warranty claim for your 4 in 1....
I was looking at it and realized that all of the servo channels are there. If you cut the plastic that covers channels 3 and 4 (throttle and rudder on most receivers) you will find that the pins are there, they are just very short. If you take a screw driver and remove the cover completely you will find that the receiver is pretty much a basic 6 channel receiver. I would guess even than you could replace this half of the 4 in 1 with just about any receiver as long as the pins lined up.
You will also notice that the pins on channels 3 and 4 are not missing or just short, E-Flite has simply taken the pins connector and put it on the OTHER side of the receiver. It plugs into a connector on the OTHER half of the 4 in 1. I would guess it goes right into a mixer that outputs to 2 ESC's....one for the main motor and one for the tail.
The conversion I did is simply to solder pins onto the "normal" side of the receiver to channel 3 so that you can connect a brushless speed controller to it. DON'T connect the main motor output from the 4 in 1 to anything. Connect a brushless ESC to channel 3. You must also still plug the receiver back into the 4 in 1 like normal. When you are done the only difference to the 4 in 1 is that you have soldered on extension pins to channel 3 so that you can connect your brushless ESC to channel 3. Oh yea, and cut off the small piece of plastic that normally covers channels 3 and 4. Once you have done this you can connect everything back together like normal, except don't connect the main motor connection on the 4 in 1 to ANYTHING. Instead connect your brushless ESC to channel 3 and then to a brushless motor. Install the brushless motor in place of the normal brushed one and away you go!
Not knowing the RPM or KV rating of the stock motor at first I chose a E-Flite brushless "Park 370" with a KV of 5400. This worked ok except that the RPM was so high that the motor got really hot because of the strain on it. I lowered the pitch a bunch and that worked better until I reached the stall speed of the rotor because the RPM was so high.
I did some further research on the forums and came across a posting about needing to be in the 3600 to 4100 KV range. My LHS didn't have the Park 370 rated at 3600 so I got the Park 400 rated at 3700 KV instead. It is a little taller, but fits. I am not sure yet if I will have a problem with the rotor hitting the top of it in extreem flexing situations, but so far so good.
The RPM is about right now with the pitch set good. I have not flown this yet because we are having a strong front move through and the winds are beyond my comfort level, but I hope to try it tomorrow.
I know it will work, however, because even with the 5400 KV 370 motor it flew great! the motor and battery just got hot. The conversion itself works. Mixing happens because the receiver is still plugged into that side of the 4 in 1 like normal, but the brushless ESC gets its setting directly from channel 3 on the new pins I installed.
I had a hardware friend do the actual solder job for me because he is much better at it. We decided the best way to connect the pins is to solder them in the same line horzontally as the short pins, but offset to the right as you look at the 4 in 1 from the receiver side. This required cutting a small bit of plastic just to the right of that so the brushless ESC servo connector fits.
I will try to get some pictures of the mod tomorrow when I am at work where I have a camera that can do it. Ask any questions. I will be happy to answer if I can.
Enjoy....
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E-Flite Brushless Conversion (I did it!) - 
