Question 25: "Hi Lurch, Perhaps you can help with prop sizes. I am flying a BME 2.8 cu. in. twin with a 20 X 8 Master Classic prop...this is about a 46 cc engine. The engine is currently turning 7000 static RPM. Eventually, as the engine breaks in and I acquire more time with the aircraft, I want to fly a 3 blade prop. As I understand it, normally, one would reduce diameter by 1 inch and keep the pitch the same. Would you care to offer any opinion on prop sizes for 2 and 3 blades for my engine? Thanks Larry"
Lurch: "I have 3 poulon 46cc engines and they all turn 20x10 props around 7000-7200 the bme should be a stronger engine I would run a 20x8 3 blade and see what it does. "
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Question 26: "Hi Eric, I want to apologize in advance. My knowledge of small scale engines is not that great. I have a basic Zenoah G-62. On the rotor (according to the online manual) , there are 2 red/black wires are coming off this, the red one is running to the source coil,which runs to the Spark plug, the other is black. The black one is not connected to anything. What is this wire, and is it used for anything? Any info is appreciated. Thanks,"
Lurch: "No problem, the black wire is the kill or P lead. When it is grounded to the engine case it kills the spark. Hook it to a switch and ground the other pole on the switch to the case."
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Question 27: "Lurch, I have a TF Giant P-51. Not satisfied with anything but a scale exhaust system, I will probably have to make it up myself. What is the flexible material used in exhaust systems? If all else fails, I can weld one up out of 4130 tubing I nave. Thanks, Jim Mails"
Lurch: "I have seen some people use stainless gas flex tube. other wise i dont have any idea what to use"
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Question 28: "Mr. Schaapveld, I am looking to fly a 4 blade prop on my Jug. You mentioned in one letter that APC makes the only working one you know of. Can you recommend a size and pitch for me? I have a Saito .91 right now and the plane weighs in at about 10 lbs. I can fit up to a 1.20 if needed to spin the prop as I have been told that the loss of eff. Might make flying tough on the .91... Any help is appreciated Ray Muratore"
Lurch: "I would contact APC and see what prop they recommend for A .91 4c. As far as going to a bigger engine I fall back on my old motto!! (BIGGER IS BETTER AND THATS WHY THEY PUT A THROTTLE ON THEM HEHEHE) any way if you have a open enough field you could always try it and see what happens. Good luck. Lurch "
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Question 29: "Have an older G38 which is causing me fits holding the prop on while starting. Tried Locktite---sandpaper --everything. What do you suggest? While running, it stays on nicely. Should I send for the newer hub configuration and install that? Another problem, even though the engines is wet---cannot start the engine by hand, always have to use a starter, though I see other guys do it by hand. What's wrong? Thanks, Jim "
Lurch: "Sounds like you might have a ignition problem? they have done some upgrades to the ignition and the hub because of the problems you have mentioned. You may want to think about a battery ignition such as R/C or C&H."
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Question 30: "Hello, Eric. I am designing a revolutionary propeller system for 1/6 scale and larger warbirds and bombers. How do I get hold of the shaft spec's for the engine manufacturers ( remember they are for larger planes so I'm not looking into ALL engines...) so the hubs will fit any popular engine? Thanks, Karl."
Lurch: "I would contact one of the spinner manufactures. Such as True Turn or Dave Brown"
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Question 31: "I'm building a yellow aircraft p-47d with a Bennett built Zenoah G-62, and would like to use a 4 bladed prop, Zinger said to use their 22-6, or their 20-8 what do you think? Won't be any trick flight, simple flying, poss a hi speed fly by but that's it. Also don't want to overheat the engine.... thanks....."
Lurch: "that sounds about rite to me I would try the 20x6 for more speed. Then go to a composite later on."
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Question 32: "I have a nosen p-47 sheeted and glassed, whats the best gas engine you would reccommend for it? want to both fly scale as well as once and a while buzz the field fast...thanks as well as what size prop?"
Lurch: "I would think a 120cc would fly it nicely. w/like a 26x10 or so prop"
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