DA 170 on L90 canisters?

Discussion in 'General Plane Discussion' started by Barry Built, Apr 1, 2012.

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  1. Apr 1, 2012 #1

    Barry Built

    Barry Built

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    I have L90 Canisters that were previously installed on my QQ120". The last engine was a 3W 170. I am now running a DA170 in the same plane. I have to cust about 3" off of one header and about 2" off the other header.

    How will this perform with the DA170?

    I am inclosing pics.
     

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  2. Apr 1, 2012 #2

    Barry Built

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    If I get pro flows I will have to re do canister mounts. I don't want to do that.
     
  3. Apr 1, 2012 #3

    yakken

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    I would think that you want to keep the header length the same.
     
  4. Apr 23, 2012 #4

    BVargas

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    Yes you will have to use a smaller dia. mount because LARGE proflows are only 3" dia. and 10 1/2 " long. L90K's are 3.25" dia and 14 1/2" long.

    Proflow recommends approx 10" header length for starters for a da.

    Header lengths need to be the same.

    The stock header length for a 3W-170 on front dump proflows seems to be ok for me :)


    BV
     
    Last edited: Apr 24, 2012
  5. Apr 23, 2012 #5

    Buttface

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    You want me to do what...?

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    I'm interested to know how smooth the throttle transition is with the L90s . I have considered that option but am torn between them and the MTW 115ks .
     
  6. Apr 23, 2012 #6

    Mithrandir

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    Not necessarily...

    the Front Jug gets about 10 degrees hotter.. (Delta T = 10).. and that is the longer header..
    considering the RPM range is between about 1200 to 6000 (6000-1200 = 4800 rpms or 80 rps) and the speed of sound in the 800'ish degree exhaust gas is approximately 250 m/s.. and include a Density-Altitude adjusted Reynolds number Coefficient of 1EE-2....when you do the math you get a delta header length = 80 rps * 250 m/s *(1/800 c) * (1 EE -2 RnC) / (10 Delta T) you get + .025 meters...

    or approximately ..

    + One Inch
     
  7. Apr 24, 2012 #7

    Bunky f. knuckle

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    You lost me after 10 degrees hotter...........

    Hell, someone on the other site said to balance cylinder temps, you lower the compression on the cylinder that is hottest.
     
  8. Apr 24, 2012 #8

    Votec Yak Guy

    Votec Yak Guy

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    Mith.....formula is missing a coefficient of ballistic synchronicity....correcting for this results in a header length differential of .31456745 inches.

    Clear now?

    :)
     
  9. Apr 24, 2012 #9

    Votec Yak Guy

    Votec Yak Guy

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    Barry, I run L90's on my 3dub 157's and 170's with the same header lengths.....no issues
     
  10. Apr 24, 2012 #10

    Barry Built

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    chrystal!
     
  11. Apr 24, 2012 #11

    Mithrandir

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    I got lost after the "Not Necessarily"

    lol

    ;)
     
  12. Apr 25, 2012 #12

    Barry Built

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    I cut the headers the same. Installed the L90 canisters. On initial ground run it seem to run and transition well. Next I need to go fly it.
     
  13. Apr 25, 2012 #13

    Barry Built

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    I hooked up an Omega pressure hyperion exhaust analizer for small 2 cycle engines. It auto ballanced the exit air pressure to an equal amount of 141.03188 coming from each exhaust. Then it equaled the heat exchange with the multi flux capasitor so cylinder heat is the exact same at 145deg after a 8 minute flight and 160deg after a 5 minuite hover. Then I installed 2 O2 sensors ina a small cat to reduce emissions. All this and I only increased weight by 2.324 oz. Now, where can I buy pltonium to power this biotch.
     
  14. Apr 25, 2012 #14

    Tired Old Man

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    With temps that low you might consider installing a standard apartment sized instahot for pre-heat and to bring the engine up to functional operating temps. With the minimal addition of weight from the Omega you should have plenty of room left over for the instahot.
     
  15. Apr 25, 2012 #15

    Classclown

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    Platinum?!? All you need are a couple of banana peelings for a flight.
     
  16. Apr 25, 2012 #16

    Mithrandir

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    boy the first liar doesn't stand a chance around here

    lol
     
  17. Apr 25, 2012 #17

    BVargas

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    I wonder if BIG "B" is ever going to fly that plane?


    BV
     
  18. Apr 30, 2012 #18

    Barry Built

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    Well, I brought it to the field, set it up and with the help from little bill V. and Mith it seemed to run like a champ.
    How ever.. I wosed out. Next weekend is rabbit.
     
  19. Apr 30, 2012 #19

    BVargas

    BVargas

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    yea, those million mile an hour winds will turn your outy into an inney every time:biggrin:

    BV
     
  20. May 3, 2012 #20

    notorious_benny

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    Hi Barry. Have you flown the DA 170 and PEFA L90 combo yet??

    I am transplanting a DA 170 into my model to replace the old 3W 157 that was there before. And am hoping to use my L90 cans as well.

    I had a 7.5 inch header length on the 3W, it would stand to reason this header length should work with the DA170 as well.

    What header length are you using? What prop?
     

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