FUEL LINE AIR QESTION:

FUEL LINE AIR QESTION: (Full Version)

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rmenke -> FUEL LINE AIR QESTION: (7/22/2007 7:29:54 PM)
Bobby-Just venting, sort of: Have been snake bit for the past week or so, and it continues. Got the 60LX back from Dub with a spank spank note regarding tightening carb correctly, he must have been correct, it has not fallen out since back. Thought the crank felt a little rough, but smoothed out just fine after the first run. Got butt kicked at last months club race, by a LR-1+ jett Q-500 with carb, and was looking forward to a return battle yesterday with reasonably equal equipment. With bringing along nephew and two more youngsters into racing, time was limited. Did not expect any problems with the 60LX. Am using Jett bladder tank and typical remote. Getting air into the line after the remote needle, so gotta be the needle nut, right? Replaced it, no good. Tried another, no good. Abandoned the stock remote and installed the new on exhaust remote. Still lots and lots of air. Changed all lines 2-3 times. I need to order some thing from Dub, and will include 5-6 packing nuts just to have spares on hand along with extra needles and crank shafts. And, yes, I will pull it out and go the bench test rout and work it out as I know I should. Just very frustrated. Do you think the air may possibly be vibration induced? Last monday, eye Doc lets me know some catract problems are just appearing, major change in eyeglass lenzes for me. Air leak forced me to race a slower backup, got butt kicked in our fast class, flying wild and erratic. Would like to write it off to temporary sight problems, but kicked their butts in the T-34s on same day. Typical of most racers and very bad loosers, I am plotting for our next race, and gotta get the 60 going, and also want a fast back up. Ok, race comittee allowed the LR-1 as semi-scale Ashley. Just happen have a "Rusty VanBaren-Ashley" begging to be finished. Baby needs power. Now, the Q-500 motor with carb. is superior to the sport models, also a cheater engine. Will go there as a last resort to be on equal footing, rather not. In your HO, can the 60LX with black pipe have a decent chance off keeping up with the Q-500 with carb. which is turning around 22-23K? Guidance oh master!!!!!!!!!!!!!

bob27s -> RE: FUEL LINE AIR QESTION: (7/23/2007 4:02:07 PM)
Not sure about that Q-500 engine ..... if he is getting 23K rpm .......thats far, far better than any of my 428 engines can do ! My real good one can just hit 20K at the line with a 8.75x9W. As for the air in the fuel line ...... Sounds like micro-bubbles. It is actually disolved gas in the fuel coming out of solution due to the pressure drop across the spray bar (suction from the engine). One big thing........ mount the needle valve on the airframe..... not on the engine. That helps a ton!! Air leaks at the packing nut are rare. It does help seal, but it is usually not that critical. Let me know how you make out.

rmenke -> RE: FUEL LINE AIR QESTION: (7/23/2007 10:15:28 PM)
Bob: Thanks for assuming that I re-read Dub's "Crap Trap" on this subject which I did. Am building a super duper test bench now, and will tackle it this week. Have the same problem with the BSE and cast 60LX, and need to resolve the thing before the next race. I just may resolve the problem with a old style carb with the needle up front. Are they still available? Do not want to bug Dub until I decide on what engine to stuff into the "Ashley". Isn't that 9" pitch a might much for a little 40? My 60's are not fond of it, turns them under the 18.5k required. Have been playing with one of the new tempurature lazer guns, with the supposed sweet area between 220-240F for our glow engines. Seems like my guys like 180 to 200 best with 200 maby pushing things over the top. If you don't have one, send me a pm address and will see you get one from son, the tool dealer.

bob27s -> RE: FUEL LINE AIR QESTION: (7/24/2007 1:40:13 AM)
the only good temp measurement is of any use, is to get the engine running exactly the way you want it to -- first..... then perhaps get a few temp measurements. Other problem..... is most of the temp devices prefere a non-reflective (flat black) surface to measure on. Few of us (jett camp) consider temp measurement of any use for the fixed wing engines. Yes, the 8.75x9W and 8.8x9 are the two favorite Q-500 props. The 428 engine taches the 8.8x9 just a hair over 19K at the starting line. The 9W is a little lighter load, and gets up in to mid/high 19k range for launch. Give on of those a try on the 60LX... when opportunity permits. Dub does not have front needle carbs any longer. Only front needle configuration is for QM40, FF and CL -- venturi installations. As noted.... move the needle assembly to the fuselage. Or mount it anywhere except on the back of the engine. Really does work.

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