Mailing List flyrotary@lancaironline.net Message #62244
From: steve Izett <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Tuning
Date: Wed, 6 Jan 2016 20:05:26 +0800
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Hi Bobby, Neil and Lynn

Thanks so much for the feedback gentlemen.
I appreciate knowing you guys are there.
I haven’t moved to mode#1/9 tuning yet. Just adjusting via the EC2 mixture control.
I’ll look for those plugs Lynn and set up the timing on the ring gear as you describe.
Thanks Neil I’ll keep an eye on the mixture, I was clearly too rich and have backed it off with Mode #2 and #3.

As far as Lambda Vs AFR goes. I understood AFR as a ratio as the name suggests and a Lambda of 1.0 for any fuel being the Stoichiometric point for that fuel.
A Lambda of 1 for what we call petrol/your gas being 1:14.7 fuel to air (by mass).

I may not get a chance to do another series of runs for a few weeks as she is on stands and I’m finish fitting the gear.

Cheers

Steve


I'm just manually adjusting the mixture at present via the mixture pot. Maybe I'm still to rich. Having chatted with Neil (thanks again Neil) I leaned out the low end. On next run up I'll see if leaning further gets rid of the missing at higher power settings.
Steve
On 6 Jan 2016, at 1:22 PM, Lehanover <flyrotary@lancaironline.net> wrote:

Try this:
 
Gap the plugs down to .010". I used a MSD-6A on both leading and trailing. No misses up to 9,600 RPM.
 
For 100% duty cycle 11.5 is the heat range you want. 9s and 10s are too hot. There is an Autolite plug
 
about the 10 heat range but I am in Florida and all of my data in Hebron Ohio. The NGK 11.5 plugs are $25.00 each and are retracted tip side electrode. Can be gapped and are ice cold. A 12.7 mixture should get you 1575 to 1600 EGTs. Once on top, lean to stumble of slight sag then back rich a bit for economy, or lean to best RPM for best power. Best timing is 25 to 27 degrees BTDC for higher octanes. Lower octane fuel works better than higher octane fuel. In that case 22 to 24 degrees. The rotary needs little advance as there is a long dwell near TDC. The timing marks on the crank are moving 3 times faster than the rotor. IE 30 degrees on the pulley is 10 degrees at the rotor.
 
The timing marks can be added to the front pulley or to the flywheel teeth. Often the flywheel is better. Divide the flywheel tooth count by 360 to get the degrees per tooth. Find TDC. Mark a flexplate (or flywheel) tooth next to your new rigid pointer with red paint (for TDC). Then turn the engine backwards the correct number of teeth to find the advance number you want to run. Mark that tooth or valley between teeth with white paint  right next to your pointer. No curve, advance weights or vacuum anything is required as the engine will start and idle at full advance. Now you can set your timing dead on and it is easy to see and check from time to time. No tuning is possible without the correct timing to begin with.
 
Both leading and trailing may be fired at once. The split timing is mostly for pollution control. It has very little affect at speed.
 
Lynn E. Hanover
 
   

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