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Engine basics => Engine set up tips => Topic started by: Warren Leadbeatter on April 03, 2007, 04:29:26 AM
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Hi guys
Been out flying my rebuilt Cardinal these past 2 days. I just cant get it to fly a good 4 cycle. If I put it up rich in a 4 cycle it fluctuates and cuts out after just a few laps. If I put it up in a wet 2 cycle it stays that way for the whole flight but is going a bit too fast. I just cant seem to find the right needle position to get it to do a 4-2-4 break. I played around with it on the ground and noticed a lot of bubbles in the fuel line when it's rich and a lot of vibration. When running in a 2 cycle it smoothes out and the bubble disappear. The tank is a standard Brodak 4 oz uniflow. I checked the prop balance and it is only slightly out so I have improved that and will try again tomorrow. The prop is and APC 11x4 Any other suggestions? BTW I have replaced the NVA as I broke the old one when I crashed the Cardinal previously. Could I have done something wrong there?
Thanks in advance.
Warren
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Warren, I pretty much have never gotten a Brodak .40 to run a 2-4-2 break. A wet 2 seems to be where mine always wants to run. I get all good runs off my B.40 and don't mind not getting the 2/4 out of it. A Rev Up 10/5 prop has been working very well for me. Give the prop a try and see how you like it. Also make sure you have a good seal on the venturi.
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I would suspect the nose, as well.......
Frank speaks correctly about a 4-2-4 break.......
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Vibration, vibration it is the enemy I have changed to a clunk tank and put about five drops of Armoral per gal. in fuel and it worked for me, it is a little hard on the glow plug but you will still get a 100 runs or more out if it. It does seam to help if you have a fuel filter and put it as close to the engine as practical. Good luck.
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DANG !!! Mr. Gilbert---- all this time (some 60+years) of Fox flying I have been lead to believe that Foxstunt 35 was the only engine that vibrates. Have I been treated like a mushroom?? You know--- kept in the dark and fed Bull ****.
Just kidding
Bigiron
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Oh no Marvin you have forget about the old Super Cyclone man does it make a Fox look like a balanced engine.
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Hi, Mr. Warren
I played with my first Brodak .40 this Spring in an ARF Oriental. I found the engine to be sensitive to prop load during and after break-in. Too much diameter too soon and the engine wouldn"t return to a fast four after pinching the fuel line for a moment. After many good runs/flights on 10/5 and 10/6 wood props, I tried several 11" dia. props and the engine behaved poorly. I then tried a Top Flight "Power Point" 11/6 (skinny blade) and the engine ran a good 2-4. No prop will work very well without the other important tips mentioned ( aircraft nose glued tight to the wing leading edge, balanced prop, Armor All or equivalent in fuel, good hot plug). Then try a Power Point 11" dia. prop. Please keep in touch and let us know how its progressing, Dave Rice
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I have never had a problem with my two B40's, one in an ARF Nobler, the other on my Brodak P40Arf. They just run in a hunking 4 stroke, barely breaking into a 2 stroke at the top of a maneuver. I have run 11-4 Zingers on the Nobler and 10.5-4.75 (I think I remember that right!) on the P40.
Any engine can cause vibration if the fuse has a resonance at the running rpm. The B40 has always seemed pretty smooth to me.
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Hey guys
I pulled the motor out, removed the tank, checked it all out, couldn't see anything wrong. Replaced it all, except for the prop which I changed to a brand new APC 10x5 and guess what? She now goes like a little rippa! Flies steadily in a 4 cycle and cuts into a 2 cycle when the nose is pointed up then switches straight back to 4 when flying level and/or inverted.
So it must have been something to do with the 11 x 4 APC prop.
Cheers
Warren
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Warren, the old DOC here, I see you say you are running APC props. I have been an advocate of Top Flite Poser Point 11-4 props which weight conxiderably less than an APC. Watched Dan McEntee work with Sean at VSC this year and his Ringmaster. I do not remember what prop they finally settled on, but, it was not an APC. Dan kept saying something about to much weight/load on the engine. By the way I set my B-40 for a fairly fast 4 stroke and it stays there most of the flight. DOC Holliday
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Gday Doc
Yes I agree. I am in the process of moving into my new house at the moment and the only props I can find at the moment are APC. I do have some TF and Hawk wood props around somewhere but cant find them right now.
Thanks
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I have been an advocate of Top Flite Poser Point 11-4 props which weight conxiderably less than an APC.
I tried the Power Point props when they first came out. They were so far out of balance that there was nothing I could do with them. I suppose they have improved some, but this is what I still remember.
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I think this could actually be a tank problem. Pop the end off the tank and see if the uniflow tube is in line with the pickup tube.
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I know it's a little late to get into this conversation, and Warren seems to have found a happy prop, but for the record my Cardinal ARC with current-version (cutaway piston skirt at rear) B-40 ran like gangbusters with the APC 10.5x4.5 in a wet 2-cycle. Not much if any break. Stock muffler. This combination flew very reliably with rare adjustments to the needle on Sig 10-10-10 fuel, Thunderbolt plug. No longer have the model but am about to use the same B-40 on a Pathfinder with Thunder Tiger 11x4.5. The APC was the best of many props I tried. Our coastal California air and elevation is probably similar to Australia, minus the salt water crocodiles.
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Don't believe I have ever used a tank without popping the end off and cleaning, checking the plumbing.. Only tanks I remember not needing to do this to were Smith stunt tanks back in the 70's.. Think it was Smith but might have been another name.. Remember they were expensive compaired to veco or perfect but they were nice tanks..