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

I would suspect the nose, as well.......
Frank speaks correctly about a 4-2-4 break.......

  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

        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

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

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

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.

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..