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I measured the voltage on the engine power buss, and with the master switch on, it is 12.5 VDC. While cranking the voltage drops to 10.2 VDC. I'm not sure what is normal, so I'm interested in any thoughts on that.
I switched the engine bus over to the front battery, and I was surprised to see that while cranking the voltage dropped to 9.5 volts. It has a rather long wire running from the front to the rear of the aircraft, so perhaps I am dropping some voltage since it is powering the coils, injectors, fuel pump, etc., though for this test, I did not have the fuel pump turned on.
I know that it does maintain the engine already running, which is really what I intended with the emergency power bypass.
The cranking RPM appears to be normal, but I have no way to measure the actual RPM, that I can think of. I did watch the EM-3 during cranking, but I did not see any RPM indication on the display. It stayed at zero the whole time, but that may be normal. I don't know.
Steve
Ed Anderson wrote:
Ok, with a separate battery powering the EC2/3 then you wouldn't think
cranking load shouldn't drop that source voltage but if interconnected - it
may. However, if the battery cranking the engine is low or dropping too
much voltage, your engine may not be making the two revs at the required 150
rpm. However, in that case, I wouldn't think you would even get the first
spark. Just my 0.02
Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com
http://www.andersonee.com
http://www.dmack.net/mazda/index.html
http://www.flyrotary.com/
http://members.cox.net/rogersda/rotary/configs.htm#N494BW
http://www.rotaryaviation.com/Rotorhead%20Truth.htm
-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
Behalf Of Steve Brooks
Sent: Sunday, November 08, 2009 7:35 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Battery Location[FlyRotary] Re: No start after
engine replacement
Ed,
That sounds like a good explanation for what I am seeing. The battery is about two years old. It is an Odyssey PC680. I have two batteries, one sits on the rear spar and runs all of the engine stuff, and the other one is in the nose an runs the avionics. I have pretty heavy cables running from the battery to the engine, 0 gauge as I recall, and they are not very long. Maybe 5 ft for the one hooked to the started, and 3 ft for the one ground connected to the engine block.
I will check the voltage as you suggested while cranking, I also have an emergency bypass switch where I cant power the engine critical buss from the front battery, so that would also be a quick test, as I could crank from the rear battery and power the EC-2 and coils from the front.
I just installed the EC-3, so I'm not too familiar with it yet. I will see if it shows the RPM during cranking. I'm not sure if it does or not.
Steve
Ed Anderson wrote:
Steve, where is your battery located? Engine compartment or nose??
Long leads can drop a lot of voltage under cranking current. New engine
may
have higher compression and may take more juice than previous engine to
turn it over fast enough. The fact that your old engine was also hard to
start makes me wonder.
Ed
Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com
http://www.andersonee.com
http://www.dmack.net/mazda/index.html
http://www.flyrotary.com/
http://members.cox.net/rogersda/rotary/configs.htm#N494BW
http://www.rotaryaviation.com/Rotorhead%20Truth.htm
-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
Behalf Of Steve Brooks
Sent: Saturday, November 07, 2009 4:46 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: No start after engine replacement
That's interesting. I had not made any changes to mode 8, but it is certainly easy enough to reset it to default. Steve
Steven W. Boese wrote:
Steve,
It might be useful to reset the EC2 timing mode 8 setting to the default
setting. My EC2's do not produce consistent or strong sparks at RPM's
less
than about 1200 if the EC2 timing is advanced using mode 8. The greater
the
advance, the weaker the spark. Occasionally there will be a strong spark,
but the timing on these is very retarded. With my EC2's, the most
consistent low RPM sparks are obtained at the most retarded mode 8
setting,
but the EC2 must be receiving CAS signals (engine running) in order to
make
this change.
Steve Boese
________________________________________
From: Rotary motors in aircraft [flyrotary@lancaironline.net] On Behalf
Of
Steve Brooks [cozy4pilot@gmail.com]
Sent: Saturday, November 07, 2009 1:09 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] No start after engine replacement
I replaced my original engine with another newly rebuilt block, and also
added the EM-3 to the installation. The old engine was hard to start,
and was also making a ticking noise when it did start, which didn't used
to be there.
After several failed attempts, and double checking the connections, I
had a neighbor help me do some testing. While the ignition test runs
fine, when checking one of the plugs, it sparks when I initially crank
the engine, and then stops. Once in a while there will be another
spark, but not very often.
I reinstalled the original CAS and have the same issue. I have double
checked the CAS connections and checked them with an ohm meter to the
connector on the EC-2 also. Everything seems to check out, yet I get
only that initial spark. I have replaced the spark plugs with new ones,
and whenever I pull one to check it, is is wet with fuel, which is no
surprise.
I am wondering if anyone has seen this type of problem, or if you have
any suggestions.
Regards,
Steve Brooks
Cozy MKIV 13B turbo
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