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Air Command 447 flight test problem

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  • Air Command 447 flight test problem

    I recently restored an Air Command 447. The engine is an overhauled Rotax 447 with a 4 blade Ultraprop, I used McCutchen 25ft blades. The first flight resulted in the copter only rising about ten feet in the air at max power and could not rise any higher. So my questions are - Is this a horsepower problem? Or a prop thrust problem? Or a too heavy or too long blade problem? Any input out there will be a great help!

  • #2
    My experience with fixed wing ultralights many years ago found that Ultrapropís did not produce nearly as much thrust as an equivalent Ivoprop, Warpdrive, or any other prop that we we tried.

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    • #3
      There have been probably hundreds of air command flying with 447 rotax and same prop with no issues ,I think the problem might be somewhere else specially if it flew like that before ,it would help if you can give us more data such as field elevation ,temperature the day you flew ,empty weight of the machine ,your weight etc .

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      • #4
        I thought the 447 Commander originally had a 23' rotor. Would the added weight of a 25' rotor do this? My 25' Skywheels weigh 69 lbs.
        Bobby Munroe
        Private Pilot (SEL)
        PRA Chapter 62 #42748
        EAA #1160523

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        • #5
          How heavy pilot ?
          How heavy machine?
          what Static RPM is prop set to?
          What altitude you flying from?
          Training?
          Need more info
          BarryK

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          • #6
            Another question to add to the list:
            What airspeed did you have at that 10ft max altitude?
            (One can pop up and fly in ground effect at very low speed but be also too slow to climb out of ground effect.)

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            • #7
              Originally posted by AirCommandPilot View Post
              I thought the 447 Commander originally had a 23' rotor. Would the added weight of a 25' rotor do this? My 25' Skywheels weigh 69 lbs.
              Your Skywheels are less than three pounds per foot of span with the numbers you report. I would expect that the weight difference can't be much from adding an extra 2 feet of blade (perhaps 5 pounds net). There will be other rpm and handling differences with rotor diameter, but the weight change alone isn't much of a factor, and if flight capability is so marginal that plus or minus a couple pounds means climb or no climb, other things need to be addressed. A gallon of gas in the tank is about that much, or a week on Weight Watchers for the pilot.

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              • #8
                I recommend you get some dual flight instruction before you fly again.

                Regards, Vance Breese Gyroplane CFI http://www.breeseaircraft.com/

                Comment


                • #9
                  Originally posted by dwood2066 View Post
                  I recently restored an Air Command 447. The engine is an overhauled Rotax 447 with a 4 blade Ultraprop, I used McCutchen 25ft blades. The first flight resulted in the copter only rising about ten feet in the air at max power and could not rise any higher. So my questions are - Is this a horsepower problem? Or a prop thrust problem? Or a too heavy or too long blade problem? Any input out there will be a great help!
                  Hi, seems this is your first post...welcome to the forum. What experience, ratings, training, do you have in gyroplanes? Your problem may not be your equipment so if we can eliminate factors of your knowlege/experience it might make it easier to zero in on the issue.
                  "at 55 I did'nt GO over the hill, I FLEW over it"

                  Sport Pilot Powered Parachute
                  Sport Pilot Gyro

                  Lifelong Member of the Dominator Fanclub.

                  Currently building an Aviomania GS2 powered by a Honda 130 HP Engine. Expected completion about two weeks. Wait a minute....I finished it!

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                  • #10
                    Originally posted by WaspAir View Post
                    Another question to add to the list:
                    What airspeed did you have at that 10ft max altitude?
                    (One can pop up and fly in ground effect at very low speed but be also too slow to climb out of ground effect.)
                    Max speed was 30mph, at 6700rpm. Engine was maxed out.

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                    • #11
                      Originally posted by Cresco750 View Post
                      My experience with fixed wing ultralights many years ago found that Ultrapropís did not produce nearly as much thrust as an equivalent Ivoprop, Warpdrive, or any other prop that we we tried.
                      I am going to try a 2 blade at 60in and see what happens.

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                      • #12
                        Originally posted by WaspAir View Post
                        Your Skywheels are less than three pounds per foot of span with the numbers you report. I would expect that the weight difference can't be much from adding an extra 2 feet of blade (perhaps 5 pounds net). There will be other rpm and handling differences with rotor diameter, but the weight change alone isn't much of a factor, and if flight capability is so marginal that plus or minus a couple pounds means climb or no climb, other things need to be addressed. A gallon of gas in the tank is about that much, or a week on Weight Watchers for the pilot.
                        I am only 170lbs, it seems like it would should handle that much.

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                        • #13
                          Originally posted by AirCommandPilot View Post
                          I thought the 447 Commander originally had a 23' rotor. Would the added weight of a 25' rotor do this? My 25' Skywheels weigh 69 lbs.
                          An extra 2ft on the blades can add that much more weight can it? Not enough to keep from lifting higher that 10 feet?

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                          • #14
                            In my opinion you didn't get higher than ten feet because you don't understand how to fly a gyroplane.

                            Please get some instruction before you hurt yourself.
                            Regards, Vance Breese Gyroplane CFI http://www.breeseaircraft.com/

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                            • #15
                              Originally posted by dwood2066 View Post

                              Max speed was 30mph, at 6700rpm. Engine was maxed out.
                              I don't think it's your equipment. It sounds to me like you were flying way behind your power curve. Not too many gyros are going to be doing much climbing at just 30mph even at max power setting.

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