David,

 

Thank you for the compliment.

 

I have installed a set of the -10 spark plugs and at this point they are long past the time where the stock plugs normally needed to be replaced.  How long they will continue to work is unknown, but at least that one data point is consistent with the study and encouraging.

 

Rather than purchasing the expensive thin walled socket, a tool was made to enlarge the spark plug well in the housing so a conventional socket could be used.  While not elegant, this was done with the engine in the plane and involved minimal expense.

 

Steve Boese

RV6A, 1986 13B NA, RD1A, EC2

 

---

From: Rotary motors in aircraft [flyrotary@lancaironline.net] on behalf of David Leonard [wdleonard@gmail.com]
Sent: Saturday, October 06, 2012 10:15 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Rotary Get-Together reminder

Steve, YOU ARE MY HERO!  Rarely outside the realm of paid research taking years have we come across such a complete, thoughtful, yet succinct exposè on any subject.

I have been using the BUR bla bla -9 plugs (stock trailing plugs) on both the leading and trailing applications for a while now with minimal effect if any (they are the coldest stock plugs sold by Mazdatrix).  Makes sense now that I read the Boese law of SAG.  I think it is time to try out some of these even colder plugs sold by Racingbeat and see if I can get a more than 25 hrs or so.  Actually, if I just use them in the trailing slot, and the -9 stock plugs in the leading slot, it should be just as effective.  The idea being not that I need them cooler when new, but there should be more allowance for core degradation before SAG begins.  Also, running cooler they may not degrade as quickly.

http://www.racingbeat.com/RX7-1986-1992/Ignition/11547.html

They are not cheap! could go through 4 regular plugs for the price of one of these... and they need a special thin-walled socket to install them and RB is charging $81 for those.  Will look around for better prices.

--
David Leonard

Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net

On Fri, Oct 5, 2012 at 3:26 PM, Steven W. Boese <SBoese@uwyo.edu> wrote:

The content of the SAG presentation last weekend at Pocahontis has been added to the website:

 

www.rotarycopilot.com

 

as a page labeled "SAG part 2".

 

The conclusion of the study is that if SAG develops on both rotors of a 13B, power to all the ignition coils could shut off and the engine would continue to run.  This is yet to be tested in flight, however.

 

The only photos of the event I took are not posted since they were of the chorus line of wives.  Sorry, you had to be there.

 

Steve Boese

RV6A, 1986 13B NA, RD1A, EC2