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Building Tips and technical articles. => 1/2 A building. => Topic started by: Chris Wellington on April 14, 2008, 10:21:46 AM
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What engines are recommended and available for 1/2a stunt that produce a reasonable sport performance ? Are the Brodaks acceptable current replacements for TeeDees on the Sarpolous warbirds etc?
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If "available" includes E-bay, Norvels are "it on a stick''. Not being imported any more I guess.
I have a Brodak first generation .049 that is generally reliable but low-power. Don't know about the later version(s). I'd recommend an .061 (AP Wasp is available) but some joker's bound to jump in and point out that's not really 1/2A. So sue me.
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Hi Ray,
Have you tried the Brodak .061?? I am guessing it could possibly match a TD?? (or at least fly the Sarpolus Warbirds, I am sure)
Bill
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My votes for the AP .061, MUCHO power, but as Ray said, its not really 1/2A
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Hi Ray,
Have you tried the Brodak .061?? I am guessing it could possibly match a TD?? (or at least fly the Sarpolus Warbirds, I am sure)
Bill
I have not, Bill...it may well be a great little engine. I've not even seen one run, know nothing about it.
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The AP Wasp is a superb running engine, and the only small engine I know that has a bronze bushed crankcase. I have run 3 of them, and all were good runners, easily equal to the Big Mig Norvel .061.
For an .049, the Medallion from C*x has a great stunt run. Also the Norvel Big Mig .049 if you can score one. The MK I Brodak is an excellent choice if you add the Nelson Head, but that makes it cost about $80 total! Tee Dee .049s run strong, but need pressure to be reliable, and won't swing as big a prop as the Medallion without overheating.
The old Atwood Shriek will pull through maneuvers well and has about the power of the Medallion, but uses smaller props to do it. I suspect that the Holland Hornet could work well if you restricted the venturi. I have never run one except on a free-flight, so I can't really say.
My painful experience has shown that only the C*x engines are happy with props as big as the C*x 6x3. All the others should use things like the APC 5.7x3, or 6x2 and older props like the Tornado 5x3. Otherwise you will get overheating about half way through your flight. C*x engines are happy with up to 30% Nitro, the others should stay under 20%. 20% oil, half and half is good for all these engines. More oil doesn't hurt anything but gas mileage.
H^^
PAW diesels are also an excellent alternative, and can swing BIG props with ease. Just be sure to use Neoprene or Vinyl fuel hose, not latex or Silicone.
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AS far as fuel goes, my AP's love PowerMaster 20/20 and i'm using Master Airscrew 6x3's cause thats what I could find.
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I'm running a 3-blade 5x3 on my Norvel .061 in the LittleAxe and it is the perfect combination! Next best is APC 6x2. I use everything from 5.7x3 down to 4.25x3 on the various .049s I have.