Wow, hehehe, lol....Apparently more of an ignition expert than you are...What the @#$% kind of BOAT ignition are you talking about ?
Diodes and tubes in 1933 ? Toroids ? Right....
Large inboard BOATS used auto engines, fired by a distributor containing a set of points opened by a cam on the shaft..The coil fired when the points opened, and advance or retard was controlled by a vacuum mechanism and weights on the points plate...The dwell time is/was set by gap between the points, and was optimized on a machine that the distributor was mounted in....There was NO electronic ignition back then...Mallory and others made aftermarket distributors to better control the spark, but nothing was electronic.....
Model airplane engines used the same kind of ignition, points and a coil...If there WAS an electronic ignition system back then, the SAM modelers would not be using points and coils on their Old
timer models today....

Kris. Kind of like the old lawn mowers? They had a magnet that spun around and passed by the coil? (maybe still do)

There's a bit of a difference between a battery-fired ignition and one that uses spinning magnets to provide energy for the coil, Crash. The current lawnmower engines. .some have CD ignitions with electronic triggers (this seems similar, no?) yet weedies use magnetos (with transistorized "triggers" inside the magneto). OLD style stuff used points and condensor along with the magneto (spinning magnets) to trigger the plugs. Some even had (GASP). . "advance" mechanisms.

Suffice to say, these ignitions, the principles behind them, the basic design as far as what the components do, and how they operate, have all been around for a very long time. They are proven, reliable, dirt simple in theory and design, and work. Just what we, as modellers, need.

Seems everyone would be applauding the fact that a proven design, and principles, were firing off the plugs in our engines. . kind of like, magnetos in modern aircraft. . dirt simple,reliable, hard to break, and almost never fail.

Say something enough times with conviction and many prople will
believe it..Nice going Kris^..
And a 2003 Lincoln is a copy of a 1917 Model T Hey, they both had spark plugs.....

Well, Ralph. . all we have to do is point to 3W's ignition, which is the same basic piece as the DA ignition, which is the same basic piece as the CH unit, which is the same as . . .. No SMT components, though they are epoxy sealed to the circuit boards, separate controllers and coils with hardwiring between them, and all externally timed using a variable timing pickup unit of some sort.

How long has the 3W unit been around? 15 years??? Trace it's lineage and design back a few decades. . .or more. Same design principles and circuit considerations were in use. Electronic theory and design does not change. . merely the available components.

One thing I'd like to point out, since RCIGN brought it up before. . .the fact that the OLD ignition did not use "Resistor plugs" . . uh. . .CM-6 plugs are NOT resistor plugs, sorry. . . that's why we have the little resistor thingie in the plug cap for a DA ignition. . right??? And, what's the object of having resistance in the secondary/sparkplug side of the ignition circuit?? RF suppression. . plain and simple, and for no other reason. You see. . you don't HAVE to have a resistor type plug, OR resistor cables or a resistor in line with the sparkplug cables. . IF you are not worried about RF radiation and interference. I doubt very much they were really worried very much abou that back in the 30's, when the only "radio interference" they worried about was how badly the HUGE radio interfered with movement around it.

After about 30 flights on the engine, and close to 5 gallons of gas, 5 props were tested today. Humidity was 85%, temperature was 82 degrees, altitude was 650 feet ASL.

Menz-s 27-10. . 6900-6950 cold, 6800 hot.. VERY noisy prop and did a lot more spinning than pulling in the air. Easily the noisiest prop of the group, but at higher rpm's did not seem to "bite" as hard as the other props.

Mejzlik 28-10. . 6850-6900 cold, 6800 hot.. medium noise level on the ground and in the air, pulls very hard and has great vertical. 2nd best prop of the group tested.

AM 28-10. . 6850-6900 cold, 6800-6850 hot, medium noise level on the ground and slightly less in the air, Pulls just a touch harder than the 28-10 Mejzlik, and my personal favorite in the way it flew the plane.

Menz-s 28-10. . 6350 cold, 6250 hot, medium noise level on the ground and the quietest of the group in the air. Pulls very well but lacks the instantaneous thrust and recovery on vertical snaps that the Mejzlik and AM give you. A great "steady-state" prop or one for flying the plane in calm conditions where the tail is not blown off line by the wind (we had 25 knot steady winds from the East above 100' today)

Mejzlik 29-10 (Modified with squared off tips . 28" overall length) . . 6400 cold, 6300 hot, good smooth power but lacks the "zip" of the 28" props and gets blown off line about the same as the 28-10 Menz. Lowest sound signature on the ground (for dB testing) and very quiet in the air.

For those interested, I have not adjusted the carburetor since the first flight, and the belly of the plane is a bit wet from excess oil/gas coating it. I could probably "tweak" another 100 or so rpm out of the engine, but I'm going to wait will I switch over to 100:1 Amsoil before I start adjusting the needles for max top end power. In the air the engine sounds just a tad rich, with a slight burble throughout the mid-range, but throttle-up is quick, without hesitation. You can also 'smell' the oil in the exhaust, showing that it is, indeed , a bit richer than necessary.

When I do tweak the needles, I'll test the 28" props again. In the meantime I'm looking to sell off the menz-s 27-10. . anyone interested?

Who makes the AM props?

AM props are available from Desert Aircraft. They are made in Switzerland. "Air Models"

Put a 3 blade on it Kris!

I don't see them listed on their web site ????

they are there, Crash, go into the "Props" part of the site. .AirModels is listed in the printed area, not with the menz, mejzlik and Bolly props.

As for a 3-blade. . know anyone who makes a 26.5x12 ??? 26-12 would be too small, 27-12 too large

I guess I could get a 27-12 and jsut cut it down a bit. . then not tell anyone.

I would bet that the 26" 3 blade would NOT be too small....

Man. . you guys have no FAITH!!

probably right. . the 2-blades are quiet enough for now. . and I am becoming addicted to SPEED. . in a vertical line, that is.