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  #41  
Old 03-12-2016, 12:22 PM
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skylor skylor is offline
 
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Quote:
Originally Posted by F1R View Post
I don't think you can use a mag hole drive on any 540 unless you built a gear reduction. On a 540 only a flywheel /crank nose will work. The Mags on a 540 are spun at an over speed RPM vs the 4 cylinder Lycs. This is why electroair never had a 540 Mag hole timing trigger solution and the same reason the PMAG/ EMAG is not yet available- very simply it is a beast of an engineering project. ( Perhaps I need to do some math here, as the 10 degree pitch spacing might be able to work in a 540 Mag hole reluctor set up)( I know that the 60-2 = 6 deg pitch spacing electro air could not be used in a 540 Mag drive)

That appears to be very nice install on your 390 and I especially admire the flywheel reluctor and pickup mount on Kirk Harrel's engine.

IIRC the mags on a 540 are driven 2x the RPM compared to the 4 cylinder in order to generate higher voltage /hotter spark. Perhaps is is only 1.5X but I am quite certain it is different than the 4 cylinder drive. I don't have an accessory case available at the moment but some AME or A&P on line will know for certain in a few minutes.

Elctroaire at one time did have a mag hole reluctor set up for the 540...a buddy mine used to have them installed on his Glassair III. He switched to Lightspeed after experiencing multiple reluctor unit failures.

Skylor
RV-8

Last edited by skylor : 03-13-2016 at 01:23 AM.
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  #42  
Old 03-12-2016, 12:47 PM
F1R F1R is offline
 
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Quote:
Originally Posted by skylor View Post
This is incorrect. The mag drive ratio of a 540 is 1:2, same as the 320/360. Also, Elctroaire at one time did have a mag hole reluctor set up for the 540...a buddy mine used to have them installed on his Glassair III. He switched to Lightspeed after experiencing multiple reluctor unit failures.

Skylor
RV-8
I suffered multiple pick up failures with an Electroair reluctor on the crank nose. The pickup mount on the nose was nothing worthy of an aircraft application. So I looked at making my own mag hole mount setup using a Slick mag for a bearing and shaft housing. Perhaps wrongly I concluded that it could not be done but Electroair told me the same thing. Now I will need to do some detailed study. Humble pie again.
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  #43  
Old 03-12-2016, 02:27 PM
F1R F1R is offline
 
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Quote:
Originally Posted by skylor View Post
This is incorrect. The mag drive ratio of a 540 is 1:2, same as the 320/360. Also, Elctroaire at one time did have a mag hole reluctor set up for the 540...a buddy mine used to have them installed on his Glassair III. He switched to Lightspeed after experiencing multiple reluctor unit failures.

Skylor
RV-8
Reference #1: PDF Page 2-5 of the 1970 Lycoming Overhaul Manual shows a typical 6 cyl. gear train diagram. The Mags spin at 1.5 X the crankshaft RPM.

A couple of diagrams above shows the typical 4 cyl. gear train with the mags at 1:1 with the crank shaft RPM
Link is Here: http://www.expaircraft.com/PDF/Lycoming-OH-Manual.pdf

Ref #2 as below :

An RV-10 Builder's Log: RV-10 IO-540 Ignition System Decision
buildingrv10.blogspot.com/.../rv-10-io-540-ignition-system-decision.html‎
27 Mar 2013 ... The IO-540-D4A5 260hp engines are shipped with: .... Most of the time, mag timing (fixed) will fire before or after an .... The 540 has a 1.5:1 drive ratio on the mags, which is different than the 1:1 ratio of the 4-cyl engines.”

It would look like a normal IO 540 can not use a Mag Hole Electroair 60-2 reluctor / pickup assembly because the mag drives are spinning 1.5 X faster than the crankshaft. That agrees with what I was told about 6 years ago.

Thankfully Dan Horton, Kirk Harrel and Frank from Quebec have put the E back into Experimental using the Ford 10 degree pitch spacing / 36-1 tooth reluctor wheel.
Thanks to Megajolt and Ford for making home brew ignitions much more within grasp for the average guy. I have an old 8N Ford tractor used for a tug that is soon going to have a modern ignition thanks to this thread!

Last edited by F1R : 03-12-2016 at 02:54 PM.
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  #44  
Old 03-12-2016, 07:04 PM
F1R F1R is offline
 
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Originally Posted by DanH View Post
This is the other approach to a timing signal, a large tab wheel and stock Ford pickups, as installed on Kirk Harrel's Mustang. In this photo the second pickup is not plugged in, as he is using one Bendix mag while building hours with the EDIS installation.

Just moving the artwork back on display where it belongs
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  #45  
Old 03-12-2016, 09:42 PM
lr172 lr172 is offline
 
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Quote:
Originally Posted by skylor View Post
This is incorrect. The mag drive ratio of a 540 is 1:2, same as the 320/360. Also, Elctroaire at one time did have a mag hole reluctor set up for the 540...a buddy mine used to have them installed on his Glassair III. He switched to Lightspeed after experiencing multiple reluctor unit failures.

Skylor
RV-8
Don't know anything about the 540, but the 320/360 Mags spin at crankshaft speed, not 1:2. The mag produce 2 spark events per rotation (at 1:2 it would require 4 spark events). The rotor shaft has separate internal 2:1 gearing that spins the rotor at half the speed of the mag. Simply looking at the gearing show the crank and mag gears are the same size, which creates a 1:1, regardless of the idler gear size.
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Last edited by lr172 : 03-12-2016 at 09:46 PM.
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  #46  
Old 03-12-2016, 11:54 PM
Frank from Quebec Frank from Quebec is offline
 
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The sixes magneto are overdriven 1 to 1.5 from the crank and then underdriven 3 to 1 for the rotor.
This way the magnets north-south poles are inverted and therefore producing electricity every 120 degress of crank rotation wich is what's needed for a 6 cylinder and the rotor is turning at the required half crank speed.
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  #47  
Old 03-13-2016, 01:21 AM
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skylor skylor is offline
 
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Quote:
Originally Posted by lr172 View Post
Don't know anything about the 540, but the 320/360 Mags spin at crankshaft speed, not 1:2. The mag produce 2 spark events per rotation (at 1:2 it would require 4 spark events). The rotor shaft has separate internal 2:1 gearing that spins the rotor at half the speed of the mag. Simply looking at the gearing show the crank and mag gears are the same size, which creates a 1:1, regardless of the idler gear size.
Bonehead reply on my part. You're right, I completely forgot about the internal gear reduction for the rotor on the mags.

Skylor

Last edited by skylor : 03-13-2016 at 01:37 AM.
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  #48  
Old 03-13-2016, 07:38 AM
vic syracuse vic syracuse is offline
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Electroair has a new mag timing housing for the pickup. I have it installed in the IO-540 in the RV10.

Vic
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  #49  
Old 03-13-2016, 07:49 AM
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David-aviator David-aviator is offline
 
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Very interesting thread...experimental aviation at its best.
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  #50  
Old 03-13-2016, 08:55 AM
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A dual crank-triggered EDIS system, like another other, require two pickups. With small Hall effect sensors and flywheel-mounted magnets, they are usually stacked along a radial, one outboard of the other. That approach is tricky with reluctors. One, the reluctors themselves are generally larger, so it is easy to run out of space. Two, the tooth width should match the width of the magnetic tip of the reluctor. That makes for interesting machining.

Look closely below. The second reluctor (currently not plugged in) is mounted so that it is advanced 1-1/2 teeth from the first reluctor, or 15 degrees.

The Ford EDIS module is hard-coded to provide fixed 10 BTDC timing above 400~500 RPM.

Kirk was very clever here. Combine the 15 degree offset and the 10 degree built in EDIS module advance, and he has a 25 degree advance. The result is a fixed timing electronic ignition without using a Megajolt controller...just a pickup, EDIS module, and coil pack.

Note that he can still incorporate a Megajolt and have variable timing on that second ignition if desired. All he needs to do is enter timing map values 15 degrees less than the desired values. For example, if 32 BTDC is desired at cruise MP and RPM, he would enter 17.

And yes, my friend Kirk is an experimenter.

http://www.experimentalairplane.com/kirk.html

[/quote]
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Last edited by DanH : 03-13-2016 at 08:58 AM.
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