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Thread: Prelim amphib pirep

  1. #1
    Senior Member randylervold's Avatar
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    Default Prelim amphib pirep

    For those interested in how our Carbon Cub SS might do on amphibs I thought I'd post a quickie pirep — I just got back from a short test flight.


    First off, due to the smaller size of the floats (1500 lbs versus the more common 2100 lbs) the plane sits lower that the typical Super Cub amphib. It is therefore seems a bit less intimidating and the sight picture from the cockpit, while different, is not as different when taxiing and flying. Of course being a bit lower it should fit in more hangars. Rudder deflection during taxiing doesn't do anything so differential braking is required to steer on the ground, no biggie.

    I put in the first notch of flaps and advanced the power with neutral stick expecting a noticably longer ground roll than I usually see in an SS. Surprise, it just sort of levitated off the runway way after what seemed like just a few plane lengths. I immediately stowed the flaps and set about stabilizing my climb and started to notice "hmm, doesn't really feel any different". I stabilized at 70-75 mph and was seeing nearly 2,000 fpm climb. Levelling off at 3,800' I powered back and did few turns and wiggles to get a feel for the controls, hmm, still didn't feel much different at all.

    I then cruised for a bit to collect some engine temp data which was the purpose of the flight. Just because I was curious I made some speed notes: at 3,000' while cruising at 2500 rpm and leaned to 8.1 gph I saw 115 mph IAS. That is very close the speed you'd see with wheels.

    Ok, back to the pattern, fly down final at 60 mph (a bit fast just for a bit of extra cushion, don't want to dent the brand new amphibs, and I'm aware that those 4" wheels probably won't tolerate being plopped too hard) and let the speed decay while raising the nose slightly in a gentle flare at what felt like the right height, feel for the pavement with the back wheels... there it is, stick back gently, but not as far as with wheels, and it settles down onto all four wheels. Wow, that was easy.

    You can't (at least I couldn't) see the floats in your peripheral vision while while flying or landing so one needs to memorize the sight picture while on the ground. Still, the adjustment was no big thing. If you lean your head to the left or right of course you can see them but I'm not sure I want to do that while landing or not, each pilot probably has their own habits there.

    In all I think the Carbon Cub SS Amphib will reset the performance bar for a floatplanes just like it has for taildraggers. I was very surprised at the performance hit in any parameter — it still flies like the "LSA brute" we all know and love.

    Our plan is to take a few weeks to collect all the test data we need for the ASTM approval and POH supplement, set pricing, and then add it to the option sheet. I can't make a hard date commitment but I'd guess we'd have all this done by April — just in time for float season.
    Randy Lervold

  2. #2
    Junior Member Table Rock Aviation's Avatar
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    Default Re: Prelim amphib pirep

    It looks great! Any ideas on what the useful load will end up being? I am guessing that the Amphib option will only be an option for the Carbon Cub SS or will it also be an option for the S2 as well?

  3. #3
    Senior Member randylervold's Avatar
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    Default Re: Prelim amphib pirep

    No reason it can't be an option for the S2 also, stay tuned.
    Randy Lervold

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    Senior Member randylervold's Avatar
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    Default Re: Prelim amphib pirep

    BTW, the tail measures 9' 8" high when on wheels for those checking hangar compatibility.
    Randy Lervold

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    Thumbs up Re: Prelim amphib pirep

    looks good! dont ding my floats Royce

  6. #6
    Senior Member Clay Hammond's Avatar
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    Default Re: Prelim amphib pirep

    Landings in Cubs on amphibs are the easiest and smoothest landings I've ever made in my life. You start laughing with yourself when every single touchdown on the runway is silky smooth. Trailing link gear makes good landings out of even the worst of them.

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    Senior Member randylervold's Avatar
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    Default Re: Prelim amphib pirep

    Jim has now flown it on/off the water twice now. The first time solo, 3-4 seconds to get off, the second time with a 220 lb pax and that took 6-7 seconds. Yo Jim, how about a pirep for the folks?
    Randy Lervold

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    Senior Member turbopilot's Avatar
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    Default Re: Prelim amphib pirep

    Quote Originally Posted by randylervold View Post
    Jim has now flown it on/off the water twice now. The first time solo, 3-4 seconds to get off, the second time with a 220 lb pax and that took 6-7 seconds. Yo Jim, how about a pirep for the folks?
    Randy, be great to see a video of that performance.
    Bob Anderson, CC11-00435, N94RA

  9. #9

    Wink Re: Prelim amphib pirep

    OK, OK!

    This is PRELIMINARY, so don't take it to the bank! I flew most of yesterday getting climb, cruise, fuel consumption, and take-off/landing distances. Beautifull day to fly, and probably put 4 hours total on the plane. Went to 12,000 three times, and read true airspeed, MP, temp, and fuel burn data points every 2,000' and every 100 RPM from 1900 to 2700 RPM. Several pages of data collected.

    Photo #1 shows a 2700 RPM run at 7960' burning 9.3 Gallons per hour. True airspeed is calculated for me in white on the blue background. Yes, that's 125 MPH true at a pressure altitude of 7650 feet! Not bad while hauling two boats along for fun.

    Photo #2 shows 113 MPH on 5.9 GPH at 8000'.

    Photo #3 shows 103 MPH at a fuel burn of 5 GPH. This is less than the 80 HP continuous rating approved by our POH. At 10,000' we could be running up to 2350 RPM and burning 6 GPH for a 80 Hp rating.

    This data will all get graphed and packaged neatly in the POH for amphibs on the SS.

    Some other notes: Rate of climb of over 1000 FPM all the way up to 10,000'. I was going to snap a phot of the EFIS at every 1000' interval, but I couldn't fly the airplane and take the photo too.

    Photo #4 shows my start of the climb test. I had to come up with a different method of gathering data. Climbing through 2,000' at Vy, VSI is showing about 1800 FPM.

    All of the above was at LSA gross weight of 1430 Lbs for float planes.

    More to come. Jim
    Attached Images Attached Images

  10. #10
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    Default Re: Prelim amphib pirep

    I have my new BAuman 1500A amphibs on N711 #107 and flew it back from Bauman in Wisconsin and had several CFI guided water landings in WI ( yes we actually found some holes in the ice) and Jim's numbers agree with what I experienced. Now have about 18 hours flight time on them. The really amazing part is the only 2-3 mph loss at cruise about the same as I experienced with the 26 inch tires so really no loss to me of any speed and or additional fuel burn which I really do not understand why unless the floats somehow are creating a better overall airfoil but certainly no complaints just OH WOW! again! Joe Birkmeyer at Bauman instalation is beautiful and quality work and in line with the quality that the CC people have demonstated on oour planes. Now we have the best of both worlds and will continue with Tundra tires in the winter and amphibs in the Summer. Regards Gary

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