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Kurt,
I'd like to see a photo of your completed plane, as the yellow checker scheme would be my choice. LK, At 7.5 lbs. yours should get some fantastic verticals! I think your inverted engine install leaves a clean look to the cowl. Karl |
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Thread OP
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Thanks guys....
Have you worked with smoke systems before ? New to me. I have the pitts style smoke muffler. From what I gather all in need is a small tank, say 4 oz and a pump activated from the transmitter. I've read diesel fuel works well. Our club has an event late June and I hope to wow the spectators with a smoke show . Any advice on pump specifics would be helpful. Thanks guys ! |
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LK,
I haven't run a plane with smoke, but would sure like to. At my field thhe guys running smoke tell me that: It uses a lot of smoke oil per flight. Smoke oil residue is really messy. A smoke pump operated by the radio is best. Usually smoke works best from a gas engine because it produces more heat. However the dedicated smoke mufflers designed for 4-stroke engines should work good. The one from Slimline comes to mind. Hope this helps, Karl |
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Kurt,
I really like that color scheme! I'll bet it really reads well in the air. That 22gt really fits in the cowl nicely. It's going to be my next Extra build for sure. It's nice to see something sensibly sized that's smaller than 28%, something that Aeroworks had before they closed their doors. I was lucky enough to get two of them. Karl |
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Last edited by extra300crazy; May 29, 2017 at 02:10 PM.
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Thread OP
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Maidened the extra and she flew great. 1/2 - 2./3 throttle on the uplines with Zoar 16x6 wood prop is all I need. I do have a couple of issues. I fail the 92 decibel noise rating at our club, reading close to 100. What would you guys suggest to reduce noise on the o.s. 1.20 four stroke ? I've heard APC props with rounder tips help, as well as 3 blade props. Possible exhaust deflector on muffler ? 2nd question is on starting I'm getting kickback, spins the prop nuts loose, especially with great planes spinner installed. Aluminum backplate on the spinner with (2) screws holding on the plastic. Any help on spinners and keeping them in place ?
Still lots of tuning to be done. Thanks guys. Awesome plane ! |
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LK,
I'm really surprized that you couldn't meet the noise requirements with the 120 fs engine. Usually slowing down the RPM's with a bigger/more pitched prop will work, providing your engine isn't lugged down already. The new Alpha series of O.S. engines have a bigger and moe quiet muffler, The one that comes on my 110a O.S. should fit the 120 well. I think that's the direction I would try. I know that I can barely hear my 72a, 81a, or 110a in the air, so the muffler has to be the answer. I normally prop my engines near 8500-9000 on the ground to take into consideration of how much they will unload in the air. Don't forget that 4-strokes have a red line rpm, after which the valves could float and damage/explode the engine. Go ahead, ask me how I know! Karl |
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Thread OP
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Well.. I purchased the new style O.S. muffler which is much larger and has a double baffle inside. I also am trying an APC 16x6 sport prop which has slightly swept blade design at the tips to reduce the noise. Last resort is I have the dubro silicone exhaust deflector that is supposed to help. So we'll test her out today and see how she goes. Getting the needles dialled in so soon the cowling will go on. CG seems good, needs a little more right engine thrust, mechanically adjusted the throws for precision IMAC setup. So far it's been a good learning curve coming from electric. I enjoy the sound of the IC engines. I think my next one maybe 2 stroke gas 74" w.s. Or so. Don't care for the slime. We'll ring this one out for a couple of flying seasons and see where it take s me.
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LK,
That new muffler should do the trick. The exhaust deflector really doesn't reduce noise, but it sure keeps my Extras clean. I orient the motor so the muffler is at the bottom of the cowl, sometimes using a 80 deg. header on the engine. With the tip of the muffler rotated and pointing down then I put on the deflector at a 45 deg. aimed down to the rear. At the end of a day's flying, it looks as if someone might have sneezed on the bottom front half of the plane. Also remember that 4-strokes have a lot less exhaust residue . 2-strokes spit out unburned fuel as they are on the intake stroke. I also use a fuel that is totally synthetic and it burns a lot cleaner. Let us know how it works out. Karl |
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Thread OP
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Here is my most recent problem and copy of e-mail sent to Hobbico. Any ideas ? This sucks.
O.S. Fs -120 Surpass II with C13 carburetor and pump. Thank you for the information. I have the engine running well. Throttle response, power is good etc. I have a major problem however and hope you can help me solve this. The engine leaks fuel very bad. I have the engine running inverted and raw fuel can be seen running all around the cylinder fins, the intake manifold etc.... I have replaced the case back cover gasket, the intake manifold gasket, all O-Rings in the C13 carburetor to no avail. It appears that the leak could be coming from the pump assembly itself, the regulator, or the plug in the back of the cylinder used to remove the wrist pin. I understand the pump and regulator are meant to be left alone and are not serviceable ? Did the Surpass II engines have a problem with excessive pump pressure / leaks ? Also I don't know if perhaps the previous owner adjusted the screw on the back of the pump which I understand is supposed to be left alone. Perhaps this could affect the pressure / leakage ? I'm getting only 7 min flights on 14 oz should be closer to 10 min I think. Please please help, Great running engine but very costly to operate with raw fuel dripping out of it. Any information, suggestions, or a contact that may be able to help would be greatly appreciated. |
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LK,
I wish I could offer some help, but I've never had a pumped engine. I heard too many reports of problems, so I only use the O.S. non-pumped ones. The pump may in fact be bad, and I think Hobbico could advise you on the parts needed to convert it to a non-pumped version. There was a thread over on RC Groups under the O.S. factory support forum where Bill Baxter of Hobbico helped someone with a pumped 1.20 do just that. Hope this helps. Karl |
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Well, I was out flying today and my canopy/hatch blew off when i was doing a KE. The hatch totally disentegrated in air. It was the 3rd time it blew off. I thought I had fixed the problem earlier by extending the pins that engage the cowl. Did not work...lol. I contacted Chiefaircraft to try and get a replacement and have not heard from them back yet. Anybody else find that their hatch didn't fit very well?
Kurt |
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Today, i got my replacement canopy/hatch from Tony at Pilot Rc. A big thanks to Freddy at Chiefaircraft as well. I checked the fit with the new one and it seems alittle off as well. It appears this fuselage was built a little different than normal. I'm gonna play around alittle more to see if I can make it better. Possibly adding some magnets. I think this might take alittle thought to keep this from happening again.
Kurt. |
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Ok so who makes a "Kit" Extra around 68" ??
I don't want a ARF. im a builder & wamt my own color scheme. Intend to use a YS 140FZ & Hatori pipe i have . Want to run the pipe internal so a kit i can modify for a pipe tunnel Any surgestions??? |
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