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Bob, glad to hear your first start. Not being able to get 6000 rpm without a prop is certainly not normal. My engine will hit 5500 rpm at idle setting without a prop. Some smoke on first start up is normal, but it should clear up in a couple of minutes of running. Your smoke could come from excess oil in the fuel you mentioned. See my comments below about "poisoned fuel"
Don't know what the cause may be, but it sounds similar to a problem I had after I rebuilt the 91 turbo block the first time. Initially, I had very good compression (120 psi) - but, I certainly did not want to damage the engine during the "break-in" (and really didn't have any idea of how to run the engine to break-it-in in the first place). Therefore, I added approx triple (maybe four times) the normal amount of oil to my gas tanks - wanted every thing internal well lubricated, you know. Well, to my dismay, the engine lost compression (like down to 80 psi) and the power was considerably decreased. Well, I look, and searched, and thought and checked and double checked - I figured that somehow I had ruined my rebuild and would have to do it over again.
Leon to the rescue! He suggested that I might have "poisoned" my gasoline with too much oil. A bit skeptical (to say the least), I told Leon I had never heard of such a thing. Anyhow, He convinced me to drain my tanks, put in fresh fuel with only 1 oz per gallon. Within 2-3 minutes of running the power was back up and the compression was back as well - so I attribute the recovery to following Leon's suggestion.
The best theory is that too much internal oil causes the apex seal to ride on a cushion of oil which lifts it away from the wall of the rotor housing. When the oil film is no longer able to contain the compression pressure - the compressed fuel mixture blows out the oil film and past the apex seal into the next chamber. This appears to not only reduce the compression and combustible mixture in the chamber (and of course power), but can interfere with mixture flow into the next chamber. Now, whether this is a shred of credibility to this theory, I certainly don't know.
The second possibility is that you have a mechanical problem. I lost one of the apex seals small triangular pieces in the engine (during a rebuild) which bound up between the rotor and the side housing. The engine would initial not idle below 2200 rpm without dying due to this resistance. I ignored suggestions from many that if you can not easily turn the flywheel by hand with the spark plugs a problem exists. After about an hour or so of running the engine "freed" up and seem to run normally (I had finally worn that small piece of metal into dust) - until on the way to Charlies flyin in Mississippi I found I had compromised a coolant "O" ring and combustion pressure was leaking into the coolant system. That resulted in an engine rebuild in the heat of a humid Louisiana summer {:<(
The point being first check for easy rotation - should be able to do it by grabbling the flywheel with both hands (spark plugs out) and rotating the engine. If it does not rotate easily then check for why not.
Second point, if rotation is easy then replace your fuel - it may be "poisoned"
I figured you would think of everything else so only had those two from personal experience to offer.
Ed
----- Original Message ----- From: "Bob Darrah" <RDarrah@austin.rr.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Sunday, September 10, 2006 9:51 PM
Subject: [FlyRotary] It runs!
Finally started my 20b on the test stand. It runs, but not very good. Using Tracy's ECU and monitor, and a long (about 10 foot) umbilical cord from the firewall, it will idle about 900 rpm, starts right up, but can hardly get 6000 RPM without prop. The timing strobe shows about 35 degrees BTDC. Seems to smoke a lot.
Possible causes:
Too much oil in gas-just dumped in a couple gulups of oil in an estamated 2 gallons of gas.
Embilical cord too long.
Intake manafold-homemade log type about 4 inch dia, with short (5in) runners, tapering top to botom from log diameter to intake port size, but constant width, the same as the ports. They match the ports well. I am in a good position to put the original intake back on to see if that will help, (last resort).
Exhaust pipe attaches to where the turbo will go and is a used auto exhaust system, about 18 feet long including muffler.
Something else, anyone got any good ideas?
I would like to get it to run better before I hang it in my Seawind. Hanging it in that airplane is no easy task.
Bob Darrah
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