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Run up Mag drop - one mag and one electronic

M

markscogg

Well Known Member
What are you seeing on your run up when you have one mag and one electronic ignition?
What RPM are you using for the test?
For me, at high RPM's the drop is greater when I turn off the mag. At low RPM's it is reversed.
Thanks
 
runup data point

Hi,
I have an o-320 in my 9A. Left side is mag right side is lightspeed

I do my test at 1600 RPM

Mag drop is 20 to 30 RPM.
Electronic drip is about 70 RPM.

Don't know if that is good or bad, but have 220 hours on since march and never had a problem.

Duane
 
IO-360 A1A 200hp
I test at 1900 rpm.
0-10 drop with Mag off.
30-50 drop with EI off. I run an electoair on the right side, with a Hall effect digital RPM display.
 
Last edited:
1900 RPM ?

Wow, 1900 RPM would be almost full power with my fixed pitch sensenich prop. I show 24" MP at 1800 RPM. That speed gives 125 drop when I turn off the mag. Half that when I turn off the EI.
You must have a C/S prop?
 
Electronic Ign Mag drop

Hi Gang,

I have the IO360 CS prop with one impulse Mag and one LightSpeed ignition.

I believe that Klaus says in his specs to expect 150-200 rpm drop when selecting the mag.

I get 0-10 drop on the Plasma II and I get 100-150 drop on the mag.

FYI

Don
RV 7 ECi Titan EX IO360
 
I have one ElectroAir EI & one Slick mag. I use 1700 rpm with my 360 & C/S prop. Here's what I see...
Mag off: 0-20 rpm drop
EI off: 75-150 rpm drop (usually about 125)
 
I have a 0-360 with one slick MAG and one lightspeed, I see a 30 rpm drop with just the lightspeed on and I see 50rpm drop when running on just the mag.
 
I have a 0-360 with one slick MAG and one Lightspeed. I drop about 30 RPM on each system.
 
ARE YOU SURE YOU'R TURNING OFF THE MAG!

markscogg said:
I show 24" MP at 1800 RPM. That speed gives 125 drop when I turn off the mag.
Click to expand...
I have a 320 fp. mag on left and a LS on the right. At 1600 rpm, when I shut off the MAG..... no change. When I shut off the LS, I see a 100 rpm drop.

At 800 rpm, IT IS REVERSED!
 
Eci 0360/180--FP Catto

Mag on Left, LS PIII on Right

Mag check at 1600rpm gives:

10-20 rpm drop when mag switched off
40-70 rpm drop when EI switched off

Cheers,

db
 
Mag drop - reversed

gasman said:
I have a 320 fp. mag on left and a LS on the right. At 1600 rpm, when I shut off the MAG..... no change. When I shut off the LS, I see a 100 rpm drop.

At 800 rpm, IT IS REVERSED!
Click to expand...

Yes, mine is reversed at 800 RPM. Drops a lot with EI off, no real drop in mag this low.

I will check the switches this weekend, but 99% sure they are correct. I can pull the breaker on the EI to test.

Thanks
 
WOT Mag drop

markscogg said:
Wow, 1900 RPM would be almost full power with my fixed pitch sensenich prop. I show 24" MP at 1800 RPM. That speed gives 125 drop when I turn off the mag. Half that when I turn off the EI.
You must have a C/S prop?
Click to expand...

I do my runup at WOT to see if my engine is producing the same power as the last flight. It is ~2100 RPM on a hot day and 2150-2200 on a cold day. Altitude also has an effect. Left Slick drops 50 RPM when off, right EMag drops 100 RPM. Engine is O-320 with 9.2:1 and prop is Sensenich 83" cruise pitch.
 
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