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-   -   DA-60 Testing ( Taming the Monster ) (https://www.rccanada.ca/rccforum/showthread.php?t=142338)

Bdegan 06-20-2012 09:04 PM

DA-60 Testing ( Taming the Monster )
 
8 Attachment(s)
Where to start.........

Myself and a few others have been having long discussions about the new DA 60 and 120.
Many people have been observing excesive vibrations with these motors in the lower rpm ranges.
A few people on other forums have said they have tried other ignitions on the DA's with some success.

I plan to run similar tests and document any differences I find.

I will be doing these tests using a DA 60. I also plan to put a tuned pipe on this motor and use it in a 3D Hobby Shop AJ Slick.

To start with, I will run the engine with the DA ignition that came with it at the original timing setting.
Then, I will run it with the same ignition with the timing sensor fully retarded.

After I document some rpm #'s and observations using the DA ignition.
I will install the RCexel ignition I bought from Thunderbolt RC, time it, and see how the engine performs. ANd most importantly, can I get a smoother idle and transition than with the DA ignition.

Below are a couple pictures of the motor, DA ignition, rc exel ignition and the 2 hall sensors. The DA sensor is the red one ;)



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Bdegan 06-20-2012 09:18 PM

Re: DA-60 Testing ( Taming the Monster )
 
8 Attachment(s)
Now, RCexel has a mounting bracket made specifically for DA engines.
The reason fo rthat is because DA uses a different ignition and timing programming than most other manufacturers.

Picture 1 and 2 are the DA specific braket. Those are photos wingburner sent me. I don't have that bracket. I will be using a generic or runiversal bracket.

Because of this I have to do a few little things to get it to the sensor mounted properly and timed to 28 degrees like it needs to be.



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bradleyban 06-20-2012 09:20 PM

Re: DA-60 Testing ( Taming the Monster )
 
Nice Brad! I'll be following this thread

Bdegan 06-20-2012 09:39 PM

Re: DA-60 Testing ( Taming the Monster )
 
I guess I should explain how the electronic ignitions work. The DA ignition and the RCexel ignition actually work opposite to each other.
The DA ignition electronically advances the timing as rpm increases and the RCexel electronically retards timing as rpm decreases.
The DA sensor is mechanically mounted at 4 degrees advance of Top Dead Center.
The RCexel is mechanically mounted at 28 degrees advanced of TDC.

Theoretically when the DA ignition is at idle rpm approximately 1600 to 1800 rpm. It is supposed to be firing at 4 degrees advance. Where the sensor is mechanically set at. So the ignition module is running at zero advance.
As the motor increases in rpm, the ignition module starts advancing the timing up to 28 degrees advance at full throttle, or about 4 to 5000 rpm.
The engine runs higher rpms than that. But those are the rpm's the ignition module is programmed for.

The RCexel ignition module is mechanically fixed at 28 degrees advance.
It electronically retards the timing down to 4 or less degrees as it senses lower rpms. AS the motor speeds up, the ignition lets the timing advance to its 28 degrees at full throttle.

Now this timing shift from low to high or back is not linear with the rpm changes.
The modules are programmed in steps.
example.......

0 to 1500 is zero degrees
1500 to 2500 is 8 degrees
2500 to 3500 is 15 degrees.

You get the idea. The numbers above are only for explaining how it works.
They are not the actual numbers. I have no idea what they actually are.......



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Bdegan 06-20-2012 09:56 PM

Re: DA-60 Testing ( Taming the Monster )
 
6 Attachment(s)
With the DA ignition....as i stated. It is mechanically fixed at 4 degrees.
So down at idle rpms the ignition should be firing at 4 degrees timing.
One fellow in the US set up a timing light with his engine. What he found was that at idle rpms, around 1700 to 1800. His timing was actually firing between 14 and 17 degrees advance. Too much.
The engine at idle would hit hard. This causes the engine to vibrate and shake.
In older heavier planes this probably wouldn't be an issue. But in todays lighter and lighter airframes, it is amplified and can look quite violent.

When DA was first shipping these engines. The hall sensor was set about halfway advanced in the screw slots.
These engines were worse. AFter engine serial # 678 ( mine is 380 ), DA stated shipping the engines with the hall sensor slid fully retarded in the screw slots.
If you send you 60 or 120 in for a check up or service. ANd the sensor is advanced. When you get it back from DA, the sensor will have been moved to its lowest position LOL. So they know something is up themselves.



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Bdegan 06-20-2012 10:07 PM

Re: DA-60 Testing ( Taming the Monster )
 
8 Attachment(s)
The first thing I needed to do was to mount up the after market braket for the sensor to see if I could get into position and working. Because I dont have the proper aftermarket part, its not a straight bolt on affair for me.

There are 2 holes drilled and tapped into the DA crankcase for the Hall sensor to be bolted to.
With the bracket I have, the hall sensor sits directly over one of those screw holes. Which happens to be the 28 degree TDC position LOL.

I could wait and order the correct after market DA bracket. But I can't wait LOL.
Or........
I can drill and tap a new hole for the second screw. I don't want to that.....The motor still has 2.5 yrs of warranty left. I don't think DA would take to well to me drilling and tapping new holes in their motor :rolleyes:

sooooooo..... I timed the motor and got the sensor in place and have 1 screw in place. The second screw is directly beneath the sensor, so I cant do a second screw.
Instead... I wrapped the bracket in a cool new silicon tape. It won't and can't move now. I tested the ignition and it gives me fire. all is ready to go.



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Bdegan 06-20-2012 10:09 PM

Re: DA-60 Testing ( Taming the Monster )
 
Now that the rcexel igniton is able to be used and it works.
I need to remove it and put the stock DA ignition back on.

I need to get some base line #'s and observations of vibrations. Then I can do it again with the after market stuff :)



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TBrum 06-21-2012 06:45 AM

Re: DA-60 Testing ( Taming the Monster )
 
Sub'd Brad!! Great write-up so far!!

wingburner 06-21-2012 03:51 PM

Re: DA-60 Testing ( Taming the Monster )
 
Brad, could you explain what you mean on mechanially mounted.

Are they not both mounted mechanically in the same spot on the engine or am I missing something here?

Bdegan 06-21-2012 05:21 PM

Re: DA-60 Testing ( Taming the Monster )
 
The DA hall sensor is attached to the crankcase set at approximately 4 degrees advanced TDC
The rcexel hall center is attached at 28 degrees advanced of TDC

Yes they are both attached using the same mounting holes. But the location of the pickup is different because the DA advances and the Rcexel retards



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