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Hi Rusty,

Looks like things are getting all sorted out - only leaves flying {:>).

I get between 30 and 50 hours on the Stock Mazda plugs running 100LL 99% of the time. I found out that having a resistor spark plug wire as well as the resistor plugs apparently degrades the spark energy sufficiently to limit me to 20 hours on plugs. However, once I swapped out the resitor plug wire for the "spiral wrapped" wire, the life of the plugs appears to have increased.

They don't burn up or even become heavily fouled, when your rpm drops a bit and the EGT on a rotor drops around 300F you know its time to change the plugs. Its intermittent and is sure to happen where it can make you pucker the most. After the first half dozen times it happens its not that bad as you know what it is - the infamous SAG! (Sparkplug Attention Getter!). It appears (Ed Anderson's theory) that the lead eventually causes the ceramic cone to become coated with lead metal/crystals. They eventually reach the point where they bleed off some of the spark energy as it is building on the electrodes in the milli(micro) seconds to get sufficient voltage to jump the gap. This bleed off sometimes causes the plug not to fire and when it starts happening frequently you loose power and EGT (I guess the EGT decreases because unburned fuel is cooling the header?)

Anyhow, nothing to worrry about if you have less than 20 hour on the plugs. I also used to carry autogas to the airport which was a pain, but decided that one fuel fire was sufficient for a life time and now go the safer route of having a grounded truck/fixed installation for my refuling.

----- Original Message -----

From: Russell Duffy

To: Rotary motors in aircraft

Sent: Monday, August 25, 2003 9:07 PM

Subject: [FlyRotary] Ready to fly

Greetings,

I fixed my brake line today, taxied around, transferred some fuel, swung the compass, cleaned the canopy, etc. Nothing left to do but hope my Lightspeed headset makes it back from repair, strap on the Nomex, and parachute, then see if it flies. Probably Sat.

In engine news, I still have some issues around the staging point. The engine doesn't threaten to quit. It just isn't smooth. I sent the injectors off to RC Engineering today, and they'll have them Wednesday. At least by sometime next week, I should know the true flow rate of the underachieving MSD's. If they really don't flow what they're supposed to, It's possible that RC Engineering can modify them to flow the same as the stock Mazda's. If that's the case, I'll probably have them do it. It would sure be nice to have matching injectors.

A question for Ed, and anyone else who uses 100LL regularly. How many hours do you get on your plugs? Do they burn up, or just get fouled? Can they be cleaned?

I've been running premium auto fuel, but it's almost $1.90/gallon, and a big pain to haul around, not to mention dangerous. I'm thinking that 100LL would be even better for the turbo than 93 octane premium, but I don't want to have fouled plugs all the time. How many people are using 100LL?

Thanks,

Rusty (6+ hours on the engine, and feeling bad about kidding Tommy about his high pre-flight time)