VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

  #1  
Old 05-15-2019, 06:44 PM
cojaken cojaken is offline
 
Join Date: Oct 2005
Location: Tulsa, OK
Posts: 32
Question New single Pmag on an O-320

I am going to replace the right Slick magneto on the O-320 in my 9A with a Pmag.

I plan to replace the right magneto which only has 120 tach hours on it since new, but is 14 years old and has therefore already exceeded Slick's recently introduced 12 calendar year overhaul requirement.

I chose to replace the right magneto because I wanted to retain the starting capability of the left magneto which has an impulse coupling, in case the Pmag should fail in flight.

I have bought a Klixon 3 amp circuit breaker/switch to put in the power supply line to the Pmag, to function as both the circuit breaker and test switch.

I plan to wire a DB9 female plug in the cockpit to enable use of the EICAD program to customize the B curve to set the Max RPM to 2816 since my fixed pitch prop is limited to 2600, the Advance Shift to -1.4 degrees and the Max Advance to 33.6

I am about to order the Pmag, HT leads, plug adapters and plugs, and would be grateful for any constructive criticism of my plan so far.
__________________
Colin
RV-9A, bought, flying

Last edited by cojaken : 05-15-2019 at 06:48 PM.
Reply With Quote
  #2  
Old 05-15-2019, 08:27 PM
sahrens's Avatar
sahrens sahrens is offline
 
Join Date: Jan 2007
Location: Northern CA
Posts: 450
Default O-360 Pmag on the right

Your set up is just like mine, except I put in a second toggle switch to handle the test function. I mounted the test switch just below the P-lead switch for the P-Mag.
__________________
Scott
RV-7 N818BG (flying)
Bearhawk Patrol (building)
Reply With Quote
  #3  
Old 05-15-2019, 08:39 PM
cojaken cojaken is offline
 
Join Date: Oct 2005
Location: Tulsa, OK
Posts: 32
Default

I have the otiginal key switch for the P leads.
__________________
Colin
RV-9A, bought, flying
Reply With Quote
  #4  
Old 05-15-2019, 08:45 PM
Bcone1381 Bcone1381 is offline
 
Join Date: Dec 2015
Location: Chelsea, MI
Posts: 32
Default

I was kind of thinking about a single three position mag switch .....Off-On-(On) where the last position is spring loaded and removes ship power from the P-mag. Switches are lighter and cheaper than a CB, and the CB life cycle of CB that gets cycled often is a consideration to me.
Reply With Quote
  #5  
Old 05-15-2019, 08:53 PM
cojaken cojaken is offline
 
Join Date: Oct 2005
Location: Tulsa, OK
Posts: 32
Default

The cb/switch I chose is a Klixon 7270-1-3

The left Slick also has 120 hours on it and is 14 years old. I am not intending to overhaul it at this time, but maybe replace it with a Pmag next year.
__________________
Colin
RV-9A, bought, flying

Last edited by cojaken : 05-15-2019 at 09:05 PM.
Reply With Quote
  #6  
Old 05-16-2019, 04:56 AM
N941WR's Avatar
N941WR N941WR is offline
 
Join Date: Jan 2005
Location: SC
Posts: 12,262
Default

Quote:
Originally Posted by Bcone1381 View Post
I was kind of thinking about a single three position mag switch .....Off-On-(On) where the last position is spring loaded and removes ship power from the P-mag. Switches are lighter and cheaper than a CB, and the CB life cycle of CB that gets cycled often is a consideration to me.
I like this idea of the spring loaded switch!

My only concern is that I like to have all switches in the UP position when on/operation. From a visual standpoint / ergonomics it is a better to have all switches in the same UP position so that at a quick glance, you know they are on. That said, I have caught myself flying with one switch in the middle position, which for me is Ungrounded and Unpowered (running off of the P-mag's internal generator). So, maybe the spring loaded switch is the better option.

With regard of using a pullable breaker for your test switch, they really aren't designed for that. I would either add a switchable breaker or a three position switch, as discussed.

If you have a key switch, your other option is to put a push button switch that drops the power to the P-mag when pressed. You can position that pushbutton switch close to your key switch, so you aren't moving your hand all around your panel.
__________________
Bill R.
RV-9 (Yes, it's a dragon tail)
O-360 w/ dual P-mags
Build the plane you want, not the plane others want you to build!
SC86 - Easley, SC
www.repucci.com/bill/baf.html
Reply With Quote
  #7  
Old 05-16-2019, 05:30 AM
Larry DeCamp's Avatar
Larry DeCamp Larry DeCamp is offline
 
Join Date: Apr 2010
Location: Clinton, Indiana
Posts: 840
Default 3 position switch ?

Where does the spring loaded 3 position switch come from ? Bill makes an excellent point about regarding ďUP means GOĒ. I am faced with the same dilemma because killing master power to check Pmags screwed up some tach time in my electronic device. One more contact , whether in a switch or a NC button IS another failure point. I am voting for the button.
__________________
Larry DeCamp
RV-3B flying w/ carb / Pmags / Catto 2b / Steam
RV-4 fastback w/ Superior XP360/AFP/G3X/CPI/Catto3b
Clinton, IN
Reply With Quote
  #8  
Old 05-16-2019, 08:14 AM
Mark33's Avatar
Mark33 Mark33 is offline
 
Join Date: May 2010
Location: Baton Rouge, La.
Posts: 668
Default Three position switches OFF/ON/(ON)

I have this exact setup with my dual p-mags on my -4. I have two DP three position switches. Off/ON/(ON). They also have a lockout between the on and off position so that I canít inadvertently turn them off and it forces me to pull the levers up to put them in the off position.

So, my normal opinion is to flip both switches up to the middle/on position and then start the engine. Then, while idling, pull one lever up and put it in the down/off position while leaving the other switch in the middle/on position. I do this maneuver to both switches and this is to confirm ship power.

Then, with both switches back in the middle position, I bring up the engines RPMís. I then pull one lever up and pull it down to place it in the off position and then push the other switch up into the up momentary position. This operation checks the self generating power of the p-mag. I do this to both switches and this confirms that both p-mags are making their own power.

So, with two, three position switches, with a lockout and a momentary position, I can do my full p-mag check in about ten seconds and itís impossible for me to inadvertently kill the power while in flight. Oh, BTW, I also have the same three position switch for the main power/starter....OFF/ON/(ON). This is a very simple and efficient setup.
__________________
Mark H.
RV-7- IO-360, EFII, Whirl Wind C/S, (Built and sold)
RV-4- O-320, Catto three blade, P-Mags (Sold)
RV-8- IO-360, Hartzell C/S (Flying)
RV-7- (Building)
Reply With Quote
  #9  
Old 05-16-2019, 08:23 AM
N941WR's Avatar
N941WR N941WR is offline
 
Join Date: Jan 2005
Location: SC
Posts: 12,262
Default

What you don't want to do is set up your P-mag switches (no one on this thread has suggested it, but I have run into it before) as Test-Off-Run. With that setup you have to pass through Off to perform your check.

With one ignition grounded and the other temporarily being grounded (shut off) as you move to the Test position, unburned fuel will be pumped into the exhaust for the few milliseconds that both ignitions are off. When the one ignition comes back online, the unburned fuel in the exhaust will light off with a bang!
__________________
Bill R.
RV-9 (Yes, it's a dragon tail)
O-360 w/ dual P-mags
Build the plane you want, not the plane others want you to build!
SC86 - Easley, SC
www.repucci.com/bill/baf.html
Reply With Quote
  #10  
Old 05-16-2019, 10:01 AM
Canadian_JOY Canadian_JOY is offline
 
Join Date: Aug 2007
Location: Ontario, Canada
Posts: 2,068
Default

A 14 year old Slick mag is definitely an item of concern. Mine were manufactured in 2005. Prior to our first flight in 2017 I pulled the left (impulse) mag and sent it out for IRAN. The list of Service Bulletins accomplished on the magneto was as long as your arm. Importantly, the SB for soft carbon brushes was required on this brand new, zero time (but old stock) mag. I was out of pocket more than CAD$500 by the time the Slick impulse mag was back on the engine. Hard to believe a brand new mag needed five hundred bucks worth of repairs as a result of manufacturing / design defects.

I've been in your position and believe I made the wrong choice. If I had it to do over again I would not spend a penny on performing the (necessary) IRAN on your Slick impulse mag. Pull it now, install the second P-Mag, sell the Slick, and never look back.
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 02:20 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.