Bill Palmer
Well Known Member
Some "Food for Thought" for those considering electronic ignition:
If you're planning to install electronic ignition, I would recommend that you consider the new Kelly Aerospace "E-Drive" starter instead of Skytec's NL. Why?
#1: To my knowledge, the new E-Drive is the only general aviation starter that is specifically designed to be immune to prop kick-back damage. See http://www.kellyaerospace.com/starters.html. Most electronic ignitions, with the exception of the E-Mag/P-Mag, cannot sense the direction of prop rotation and therefore can technically fire into a prop kick-back (more on prop kick-back below). The Skytec NL wire-wound starter protects against prop kick-back, but it does this with a shear pin which requires starter disassembly and pin replacement in the event of a prop kick-back event. In other words, the Skytec might also be used with electronic ignition as long as you don't mind taking the starter apart to replace the shear pin in the event that prop kick-back occurs. In my opinion, the E-Drive's "immune" (clutch) design is a much better solution than a replaceable shear pin.
Prop Kick-Back: If a low-voltage condition occurs during start-up (weak battery combined with high starter load and/or poor connections), there is a possibility that an electronic ignition could operate in an intermittent mode; firing into reverse prop rotation or well before TDC and thus damaging the starter. Early Lightspeed ignitions required a minimum of 8.5 volts to operate and were somewhat prone to this problem. Accordingly, Klaus redesigned the Lightspeeds to operate at a much lower voltage (6.2 volts). He says that his redesign eliminates the prop kick-back problems with new Lightspeed ignitions (the Lightspeed now has a lower minimum operating voltage than the typical starter solenoid). All Lightspeed ignitions shipped after December 2004 operate at 6.2 volts. Older Lightspeed ignitions can be modified to run at 6.2 volts minimum. On the other hand, the Electroair ignition is less tolerant of a low-voltage condition than the Lightspeed ignitions (the Electroair requires 8 volts minimum), so prop kick-back is a "more likely" possibility with the Electroair. Not that a prop kick-back is "probable" with the Electroair (just keep your battery well-charged and all connections tight!), but it is just "more likely" with the Electroair than Lightspeed. Although the E-Mag/P-Mag ignition can sense the direction of prop rotation and, thus, avoids firing into a reverse prop rotation or before TDC, this relatively new electronic ignition comes with its own set of "issues" per other threads.
Side Note/Opinion: Regarding E-Mag/P-Mag: To my knowledge, there are very few, if any, electronic ignitions which successfully combine long-term reliability with integral packaging of the coil and electronics (high EMI environment). Also, the E-Mag/P-Mag electronics are required to operate in a much higher temperature/vibration environment (engine conditions). I wish E-Mag/P-Mag and their customers success (experimental innovation is great!), but they're sure climbing a tall mountain EMI/temperature/vibration-wise!
#2: The "E-Drive" draws half the starting current of the Skytec NL. See http://www.kellyaerospace.com/Edrive.html.
#3: An "E-Drive" starter installation is lighter than the equivalent Skytec NL installation. Note that the Skytec NL starter is two ounces lighter than the E-Drive (Skytec 9.4 lb.; E-Drive 9.5 lb.), but the Skytec overall installation can be several ounces heavier, particularly for a rear-mounted battery. Why?: The Skytec requires a heavier 2-gage starter cable instead of the 4-gage starter cable required for the E-Drive. The reason for this is that, per advantage #2, the E-Drive draws half the starting current of the Skytec NL.
BOTTOM LINE: In my opinion, certainly for electronic-ignition-equipped engines and arguably for magneto-equipped engines as well, the "E-Drive" is now the preferred starter over Skytec's NL. In other words, the new "E-Drive" is now #1. The Skytec NL is still "Excellent," but it's no longer "King of the Hill."
Here's a few pictures of the E-Drive I'm planning to install on my IO-360 angle-valve (with Lightspeed Dual Plasma III ignition):
http://img527.imageshack.us/img527/6597/edrive6kx7.jpg
http://img527.imageshack.us/img527/9738/edrive2wt2.jpg
http://img527.imageshack.us/img527/5219/edrive5il4.jpg
Best Regards,
Bill Palmer
Chino Hills, CA
RV-8A Still In-Work!
If you're planning to install electronic ignition, I would recommend that you consider the new Kelly Aerospace "E-Drive" starter instead of Skytec's NL. Why?
#1: To my knowledge, the new E-Drive is the only general aviation starter that is specifically designed to be immune to prop kick-back damage. See http://www.kellyaerospace.com/starters.html. Most electronic ignitions, with the exception of the E-Mag/P-Mag, cannot sense the direction of prop rotation and therefore can technically fire into a prop kick-back (more on prop kick-back below). The Skytec NL wire-wound starter protects against prop kick-back, but it does this with a shear pin which requires starter disassembly and pin replacement in the event of a prop kick-back event. In other words, the Skytec might also be used with electronic ignition as long as you don't mind taking the starter apart to replace the shear pin in the event that prop kick-back occurs. In my opinion, the E-Drive's "immune" (clutch) design is a much better solution than a replaceable shear pin.
Prop Kick-Back: If a low-voltage condition occurs during start-up (weak battery combined with high starter load and/or poor connections), there is a possibility that an electronic ignition could operate in an intermittent mode; firing into reverse prop rotation or well before TDC and thus damaging the starter. Early Lightspeed ignitions required a minimum of 8.5 volts to operate and were somewhat prone to this problem. Accordingly, Klaus redesigned the Lightspeeds to operate at a much lower voltage (6.2 volts). He says that his redesign eliminates the prop kick-back problems with new Lightspeed ignitions (the Lightspeed now has a lower minimum operating voltage than the typical starter solenoid). All Lightspeed ignitions shipped after December 2004 operate at 6.2 volts. Older Lightspeed ignitions can be modified to run at 6.2 volts minimum. On the other hand, the Electroair ignition is less tolerant of a low-voltage condition than the Lightspeed ignitions (the Electroair requires 8 volts minimum), so prop kick-back is a "more likely" possibility with the Electroair. Not that a prop kick-back is "probable" with the Electroair (just keep your battery well-charged and all connections tight!), but it is just "more likely" with the Electroair than Lightspeed. Although the E-Mag/P-Mag ignition can sense the direction of prop rotation and, thus, avoids firing into a reverse prop rotation or before TDC, this relatively new electronic ignition comes with its own set of "issues" per other threads.
Side Note/Opinion: Regarding E-Mag/P-Mag: To my knowledge, there are very few, if any, electronic ignitions which successfully combine long-term reliability with integral packaging of the coil and electronics (high EMI environment). Also, the E-Mag/P-Mag electronics are required to operate in a much higher temperature/vibration environment (engine conditions). I wish E-Mag/P-Mag and their customers success (experimental innovation is great!), but they're sure climbing a tall mountain EMI/temperature/vibration-wise!
#2: The "E-Drive" draws half the starting current of the Skytec NL. See http://www.kellyaerospace.com/Edrive.html.
#3: An "E-Drive" starter installation is lighter than the equivalent Skytec NL installation. Note that the Skytec NL starter is two ounces lighter than the E-Drive (Skytec 9.4 lb.; E-Drive 9.5 lb.), but the Skytec overall installation can be several ounces heavier, particularly for a rear-mounted battery. Why?: The Skytec requires a heavier 2-gage starter cable instead of the 4-gage starter cable required for the E-Drive. The reason for this is that, per advantage #2, the E-Drive draws half the starting current of the Skytec NL.
BOTTOM LINE: In my opinion, certainly for electronic-ignition-equipped engines and arguably for magneto-equipped engines as well, the "E-Drive" is now the preferred starter over Skytec's NL. In other words, the new "E-Drive" is now #1. The Skytec NL is still "Excellent," but it's no longer "King of the Hill."
Here's a few pictures of the E-Drive I'm planning to install on my IO-360 angle-valve (with Lightspeed Dual Plasma III ignition):
http://img527.imageshack.us/img527/6597/edrive6kx7.jpg
http://img527.imageshack.us/img527/9738/edrive2wt2.jpg
http://img527.imageshack.us/img527/5219/edrive5il4.jpg
Best Regards,
Bill Palmer
Chino Hills, CA
RV-8A Still In-Work!
