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Thread: Federal 2200 hydraulic skis ground ops/landing and takeoff ops

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    WindOnHisNose's Avatar
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    Federal 2200 hydraulic skis ground ops/landing and takeoff ops

    I have a question regarding flying/ground ops of Federal 2200 hydraulic skis. I bought a set from a mechanic in AK several years ago and Darrel Starr helped me renovate these and I have enjoyed them a great deal...especially this winter with all the snow we have.

    My super cub is now hangared at the airpark (update on that will follow). The airpark runway is about 3500 ft and the agreement is to keep one half of the length plowed, and the other remains unplowed. In order to get to the plowed part I have to taxi over a hundred feet of snow covered taxiway, and I have not tried this up to this point.

    I know that there is a notation that I am not to cycle the gear from gear up/skis down to gear down/skis up, or vice versa, while on the ground...and I understand why. When the weight of the aircraft goes over center of the arc of the ski armature there is quite a significant force that is exerted as the wheels go over center.

    So, I have the cub with wheels down, skis up as it sits in the hangar and I want to know if any of you have taxied over/taken off over considerable snow? By the same token, suppose I choose to land on snow with the wheels down/skis up. The wheels only protrude 2 inches below the skis when the wheels are down...will this much drag cause me a problem.

    I am not wanting to try this based upon my familiarity with what happens when I might land an amphib on water with the wheels down...

    Any input would be greatly appreciated.

    Randy

  2. #2
    1piece@atime's Avatar
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    Although not federal 2200s, I land and takeoff with my aero ski 2800 retracts with the wheels down. It’s a lot of drag and requires some power to keep the tail down with certain conditions. With the aero ski system i have no choice, it requires landing with skis up then manually dropping them with a pry bar when I’m in snow. Good luck and hopefully someone has the answer your looking for.


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  3. #3

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    I pump my hydraulic skis up and down on the ground all the time. Fluidynes and Flilites that I’ve flown say don’t pump them up or down while in motion. Simple deal. Come to a stop before pumping.
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    If your 2200 federals have external retract cylinders like my awb 2500s then I
    Think the only operating restrictions are “ Do not extend or retract while in motion on the ground” and should have a placard to that affect. I have been flying my awb 2500s for 30 years on a Citabria and jack them up and down on
    The ground. I installed valves so I can jack the ski I want up or down to turn in
    A tight spot.
    Stan
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  5. #5
    mvivion's Avatar
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    Randy,

    As others have noted, there should be no restriction from cycling those skis on the ground as long as you’re not in motion.

    As far as taxiing across snow covered areas with wheels down, it depends. For example, at Fairbanks International, they groom the entire east ramp for skis. Navajos, Caravans, and other relatively heavy wheel planes regularly taxi over that snow pack. Right up till it starts to melt. Then the airport scapes all the snow off.

    So, if that snow you’re talking about is compacted from ski planes etc, you can probably taxi over it with no problems. Until it gets warm and punchy.

    But, if you want, I’d taxi out to the snow, crank the skis down and launch on skis.

    MTV
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  6. #6

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    Landing with skis up in snow is generally a non-event except you will need extra power to taxi.
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    www.SkupTech.com mike mcs repair's Avatar
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    you are gonna piss the strait ski pilots off if you put Ruts ACROSS their snow pack...

    as others have stated, it doesn't hurt the ski to pump weight of plane....

    they JUST DON'T WANT YOU TO DO IT WHEN IN MOTION, BECAUSE ONE SIDE MIGHT GO FIRST, AND ZING!! OFF IN THE TOOLLIES YOU GO...

  8. #8

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    We have had a couple of cases of the hydraulic piston rod being bent caused (we think) by operating the skis over center with a load in a C185 with Fluidyne 3600's. If the 2200's have the same size hydraulic cylinder/piston rod, probably no problem. If not, who knows?
    Last edited by Randyk; 03-11-2019 at 10:48 PM. Reason: Expansion
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    On a Cub?

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    Once the ski go's over center it takes a lot of force to get it back even with a cub. My very expensive position valve started leaking after raising the cub onto wheels. As far as landing with the wheels down it is not a huge event but you will stop short. You need a lot of power to taxi with them down but it can be done, just keep the speed up and you will be fine. Check out what the pilots with penetration skis are doing and follow that example.
    DENNY
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    What is this "over center" you guys refer to? I can see how a long arm ski on a heavy airplane could test the hydraulics but that would occur under hydraulic load, wouldn't it? When the ski is pumped down on the ground the airplane's weight transfers to the ski and the airplane's tires crawl forward onto the ski. The weight is supported on the tire. To pump skis up is opposite. Pumping my Fluidynes up or down on the ground doesn't look like a high stress event but I'd think the Denali fliers are in the top 1% of heavy use Fluidyne users so their skis get cycled a lot. Interesting stuff. I've never heard of bending hydraulics on skis.

    My long arms are at the maximum mechanical disadvatage when the skis are up. Usually to pump them down begins with very little resistance and by the time they reach the point of resistance the arms are close to vertical. If I tried to pump skis down while the plane was supported by the skis in the retracted position? I could imagine that causing a problem, but I usually don't pump skis up unless the surface will support the airplane on the tires. Never say never but that's the usual situation.
    Last edited by stewartb; 03-12-2019 at 06:53 AM.
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  12. #12
    WindOnHisNose's Avatar
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    These comments are very helpful, fellas. Thank you. I enjoy the diversity that is represented here, and wish there was a venue like Supercub.org in my area of medicine in which frank and honest discussions can be had...it just doesn't work like that in medicine, it seems.

    Mike, I also appreciate your observation that one needs to be careful not to leave "ruts" in the snow for straight ski pilots to deal with. Important point.

    Thanks very much!

    Randy

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    I have not looked close on the fluidyne but on the Federals the arm will come up and hit a stop bolt. If it goes over center even with no weight on the ski or tire it will bind when you try to raise the ski (one of them angle/force things). I had to put a sleeve on mine to make it work smooth. My IA mentioned it before we started mounting the skis, I would have never figured it out on my own, but once you know what to look for it is obvious.
    DENNY

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    mvivion's Avatar
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    ooops

    MTV

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    Randy,
    I used 2200's for years on the Cub for spring bear hunts. The strip at Valhalla
    Lodge was normally bare and all the spike camps were snow covered. We regularly landed with wheels down because lots of the strips were not flat. On tilted ground it was easyer to maintain directional control compared to just ski bottoms. In certain snow conditions, it is considerably harder to get started, but as far as flipping over because of 2" of tire sticking below the bottom, isnt happing as you are now just a "penetration" ski. If you are real light in certain snow your tail will raise early because of the drag initially, but as soon as you get moving that isnt a factor. Good luck and really nothing to worry about

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  16. #16
    WindOnHisNose's Avatar
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    Quote Originally Posted by TurboBeaver View Post
    Randy,
    I used 2200's for years on the Cub for spring bear hunts. The strip at Valhalla
    Lodge was normally bare and all the spike camps were snow covered. We regularly landed with wheels down because lots of the strips were not flat. On tilted ground it was easyer to maintain directional control compared to just ski bottoms. In certain snow conditions, it is considerably harder to get started, but as far as flipping over because of 2" of tire sticking below the bottom, isnt happing as you are now just a "penetration" ski. If you are real light in certain snow your tail will raise early because of the drag initially, but as soon as you get moving that isnt a factor. Good luck and really nothing to worry about

    Sent from my LM-X210 using SuperCub.Org mobile app
    Thank you, TurboBeaver! That is extremely helpful. It has been my hypothesis that the 2200 Federal hydraulic skis become "penetration" skis when landing wheels down on snow, and your input confirms that this can be safely accomplished.

    Having written that, after getting this last 10" of snow in the last 3 days I really am looking forward to landing on snow with my wheels down NEXT SKI SEASON!!!

    Take care, and thanks, again.

    Randy

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    TurboBeaver's Avatar
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    Quote Originally Posted by WindOnHisNose View Post
    Thank you, TurboBeaver! That is extremely helpful. It has been my hypothesis that the 2200 Federal hydraulic skis become "penetration" skis when landing wheels down on snow, and your input confirms that this can be safely accomplished.

    Having written that, after getting this last 10" of snow in the last 3 days I really am looking forward to landing on snow with my wheels down NEXT SKI SEASON!!!

    Take care, and thanks, again.

    Randy
    Welcome Randy,
    Just for fun with a little thread drift....
    One fall Kelly Vrem and I were tag teamed up togeather both flying off M&H drag slicks on 15" mag wheels.
    We were having an early winter with lots of hunters still out on ridges. One was very tilted and we both tryed it with different tire preasures and neither of us could handle the strip with about 6" of new snow. Kelly flew into Birchwood and had a set of 15" studded car snow tires, installed on his wheels! Came back and went up and it was no problem to land with them! Amazing some of the things that can be done with a little " outta the box" thinkin.

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    For anyone with Datum skis: those can also be landed in deep snow, wheels down. You can ALMOST take off too, but not quite. Grass landings, skis down, works too, but same deal with the take off. Don't ask how I know this.
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  19. #19

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    Quote Originally Posted by courierguy View Post
    For anyone with Datum skis: those can also be landed in deep snow, wheels down. You can ALMOST take off too, but not quite. Grass landings, skis down, works too, but same deal with the take off. Don't ask how I know this.
    Thanks for the 'test' I'll try not to confirm your findings.
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