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Thread: Power flow installed,,,, well mostly

  1. #1
    Member Float Pilot's Avatar
    Join Date
    Oct 2006
    Kachemak Bay Alaska

    Default Power flow installed,,,, well mostly


    C-172N Stock engine and exhaust
    98 hours since major.
    HORTON STOL wings
    No wheel pants
    25 gallons of fuel
    Me and some survival gear
    Gross weight of 1865 pounds
    CG of 40.00 inches

    Conditions: Not Perfect
    Temp: 40F
    BARO: 30.03
    Alt: 80ft above sea level
    Wind: Direct Cross wind at 6-8 knots with gusts to 15 knots.
    Paved: slightly uphill. Runway 22 Homer Alaska.

    Take-off Distance from a stopped position:
    400 feet with cool oil
    390 feet with hot engine and oil.

    Time to 3,000ft agl altitude from a full stop on the runway:

    Full Stop on runway to 3,000 ft AGL with two people on-board ( 2,060 lbs gross weight and a CG of 39.71)
    4 minutes 28 seconds, Before Power Flow.


    With the plane loaded between 2,035-2,055 pounds I tried the climb to 3,000 ft agl from a full stop on the Homer runway.
    This time it took 3 minutes and 22 seconds. Then I did it again and did it in 3 minutes and 20 seconds.
    The temp was 40F, the baro pressure was 30.02, the winds was a cross wind at 7 knots.

    The time to 3,000 ft agl was over a minute less.

    Take-off from full stop after installation:

    I was too tired to unload and de-fuel the plane. So I flew take-off runs from the same position and in the same basic conditions as before,
    HOWEVER I was now at 2,035 to 2,055 pounds as compared to a previous 1865 pounds.
    I made three take-off runs form the exact same location. All three were right at 390 feet.
    The same as the old system was able to do with 190 pounds less weight.

    Cruise RPM after install:

    Before the power flow at full throttle 3,500 ft altitude and 27 degrees F. = 2,500 rpm indicated on tach.
    After Power Flow installation at full throttle, 3,500 ft altitude, 28 degrees F, = 2,620-2630 rpm indicated on tach.

    My tach actually reads low, so I was really a touch over 2700 rpm at after install.

    As for installation,
    The instruction are a tad weak. They bounce back and forth between the two types. Classic and Short Stack. They should split those.
    Also they could use a couple more photos or drawings and they should explain things in better sentences.

    What they really need to do is make a couple short DVD videos of installation showing the steps and just include that in the kit. That way you could see it before you hit the hangar floor.
    For the amount they charge, it would be pennies to add something like this.

    We had to trim a tapered piece for my Carb Heat hose. And the new position of the carb heat outlet required that we stop everything and drive 15 miles into town to buy a longer piece of 2.5 inch scat tubing. They did provide a longer piece of 3 inch tubing in the kit for the cabin heat. That was barely long enough. The cabin heat vents off the opposite side of the original muffler and thus the new line makes a long trip. I was pretty cold on the way home, SO I will need to find a better way... My plane was already cold with the original heat set-up.

    They also have a template to make a hole in the bottom of the lower cowling so you can have the exhaust ( muffler) support rod come through. In my case it was a good thing the template was confusing, because my cowling was modified long ago with a big lower open area around the nose wheel and thus did not really require a new hole.

    It took about 4.5 to 5 hours for the install.

    The only real problem was the Challenger filter system.
    They have similar locking studs to what I have in the old Bracket Filer. BUT... they turned out to be too big in diameter and a little too short. So we could not get the new filter attached.
    Instead of spring loaded locking studs (Bracket) they attempted to use a thick foam gasket for tension. It does not work so great.

    Maybe if it had the original Cessna filter on my plane... I do not know what originally was mounted there. They should have made a couple of options. Now I have a Bracket Filter

    And they make you install the tiny pins in the ends of the locking studs yourself. That did not work very well because they had drilled grossly undersized holes.
    Also that turns out to be a separate STC from Challenger, Which is not inside the box when you open it. Instead you have to call or mail Challenger to get the STC sent to you...

    As it was, I had to use the old Bracket filter ( I washed out the sticky foam with de-natured alcohol to get more air through it. ).. Today I will make some locking studs that will work with the backing plates I have installed in my carb intake.

    The new exhaust makes more noise... More of a rumble that is directed towards the rear of the plane.
    Attached Images Attached Images
    Floatplane,Tailwheel and Firearms Instructor- Dragonfly Aero
    Experimental Hand-Loader, NRA Life Member

  2. #2
    Join Date
    Apr 2006


    Send the Challenger back and get a Donaldson.

  3. #3
    Join Date
    May 2013
    Talkeetna, AK


    Your exhaust system looks great. Question. Did you get your RPM increase with the same old air filter before you washed the oil out or after? Now that you have washed the filter to allow more airflow you may want to try running without the filter for a spin. May very well see another increase in RPM.

  4. #4
    Member Float Pilot's Avatar
    Join Date
    Oct 2006
    Kachemak Bay Alaska


    I had already washed out the foam filter in the Bracket a couple weeks ago. My rpm changes are based upon the same filter in the same conditions in the before and after test.

    These pics are while we were still installing.... It does look a bit busy it there....
    Attached Images Attached Images
    Floatplane,Tailwheel and Firearms Instructor- Dragonfly Aero
    Experimental Hand-Loader, NRA Life Member


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