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Thread: Wheel penetration skiis

  1. #41
    aktango58's Avatar
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    George- Why AOG?

    Certification approval, or broken?
    I don't know where you've been me lad, but I see you won first Prize!

  2. #42

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    broken

  3. #43
    aktango58's Avatar
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    Do you want to elaborate:

    beginner pilot, bad luck, bad design? Wear? idiot neighbor ran into them with snowplow?
    I don't know where you've been me lad, but I see you won first Prize!

  4. #44
    mvivion's Avatar
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    Yes, George, how about an explanation of the troubles. I worked a set of those skis pretty hard for several hundred hours, with no problems whatsoever, so I'd be curious to hear what sort of problems you've encountered.

    MTV

  5. #45

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    We installed our skis last year and ran them about 50 hours. We were pleased with the performance. They were on our Husky and displayed at the AK Airmen's show last May. Our friends, Hans and Peter, got them for their Cub and Husky and installed them this year. About $20k a set, because of the exchange rate, plus installation. Three different installers -- all who have installed many sets of skis.

    Peter and Hans broke rod ends almost immediately after installation. We then pulled ours, and on ours, one rod end was bent. We grounded our plane, and have been waiting for a shipment from Europe since early December, but still no parts. There has been discussion back and forth, and we believe that there needs to be a re-design to strengthen that area. There are also rigging issues that would frustrate someone interested in a professional installation.

    We are optimistic that there will be a re-design and the installation issues resolved. Until then, we can not recommend these skis.

  6. #46
    Dave Calkins's Avatar
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    Aktango, on the Husky there is no bolt-on option on their ski-gear.

    Mike, I know the new arm and attach points and the Husky set-up mimics the old style. In order to use the new arm, one needs to re-desing Aviat's inboard-welded-on fitting for their Aero-gear leg.

    George M., Those are beautiful skis! They are the answer.

    I cannot be certain, as I have not laid eyes on Peter and Hans' broken Heim joints (rod-ends), but I saw both installations, and it appears to me that in the wheel-retracted position, the tire is being 'scrunched' pretty hard against that beautiful molded-graphite retract arm, even at rest on the skis. It is a function of the fittings being attached in front of the wheel axle and the clearance between tire and retract arm decreasing as the tire retracts. Any more pressure down onto the ski with the weight of the airplane in, say, landing mode, will certainly exacerbate the issue, and the Heim joint is the weak element receiving the brunt of that load. Thomas will figure it out, he's done a great job producing those beauties. Still, a shame to have your Aircraft On the Ground.

  7. #47
    mvivion's Avatar
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    George,

    Thanks for clarifying. I'm struggling to visualize the failure point, even with Dave's further description.

    Has Thomas redesigned the attach gear recently? I know he has lightened them up a little since we bought ours. We sure didn't have any problems with installation, nor did we have any sort of failure, and there are a lot of these skis floating around the Alps as well. The attach gear and hydraulics made our FAA guy crazy, but they work, so....

    I hope Thomas gets things figured out, soon. They are beautiful skis, and the performance is impressive.

    Sorry to hear of your troubles with them.

    Dave, you can order "ski landing gear" from Aviat for the Husky, which is set up for the Aero 2800 skis (or the RF 8001's). Are you saying that that gear isn't compatible with the newer Aero rigging? All this visualization has my head about to explode...

    MTV

  8. #48
    Ursa Major's Avatar
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    Quote Originally Posted by Matt 7GCBC
    As MTV said, it is amazing how much drag just a small area of tire penetratring through the ski can create. Knowing the difference in performance on my Aeroskis with the skis up or down, I would hesitate to go with a wheel penetration ski if there is an option for retracts. Just getting the rear ski wheels out of the snow more and putting the rear ski axle on top of the ski on my aeroskis increased performance immensely. Look at the photos in my gallery to see what I'm talking about. .
    Matt,

    Your pics answered a lot of my questions

    Thanks
    Mike

  9. #49
    aktango58's Avatar
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    George,

    any chance you could post a pic or three of these skis?

    I am a year or two from having 20K, but would like to see what you are talking about.


    Dave, I did not know about the no bolt on for husky, (another reason for a cub I say ). I do believe that the husky weld on fitting does offer the attach hole below the axle, which puts the ski below the tire, allowing the better performance. But I should call to confirm...

    I want to thank you guys for sharing your experience here. We all can learn from this type of input!
    I don't know where you've been me lad, but I see you won first Prize!

  10. #50
    Widebody's Avatar
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    Thanks Dave, no check yet, waiting for a call.

    I'm not a novice with skis and know what I need for my
    conditions/purpose. That's why I'm going with Landes,
    along with the reports, it's confirmed my decision.

    You cannot beat straights for performance and I have a
    set of Aero 3000's when I need them and yes they are great guys.

    Time to try something new I guess.

    Thanks to all,
    Brad

  11. #51

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  12. #52
    Dave Calkins's Avatar
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    a photo of the graphite retract arm on the new RF ski. Gorgeous! The 'offending' rod-ends are visible.



    Also, a photo of the A-1B Aero R2800 install. On the Aviat "Aero" ski gear (manufactured by Aviat), there is no room for a bolt on saddle for the inboard fitting tabs. The tabs are welded on. Note the outboard tabs are mounted in front of the wheel axle. On these skis, wider plastic has been installed, and the aft section of the 'forktail' has been closed over with the wide plastic. The front edge of the aft side of the tire cut-out has been formed up to not dig snow. The outer edges of the plastic have been bent in a sheet metal brake to avert catching the plastic if a side-slide occurs. Next is to remove some of the wider plastic area near the nose of the ski to help with the fore/aft area 'problem', and then install the tailwheel mount on top of the ski instead of the bottom, as has been mentioned. I've talked to several guys who have been modifying the R2800's to get them 'right'. No one has claimed victory yet, but I'm sure it's there. These are a simple and light "proper" wheel ski that just needs a bit of 'optimizing'.


  13. #53

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    wheel penetration skiis

    I am restoring an Aviat Husky A1 that had a vist from a tornado and it's going to be a float and ski plane when it flies. George I notice that the pictures of your Husky with the wheel skies have different gear than mine. You appear to have bungees in the airstream like the supercub. Husky bungees are a royal pain in the ass. So I'm curious is this a "c " model mod that I haven't noticed yet or somebody else's? This is a little bit off topic but threads do get to wandering around.

    Gabe

    I noticed that you do not have spades on the ailerons so you must have a C model.

  14. #54

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    It is an A1B converted to extended Cub gear and the Alpha Omega system through STC.

  15. #55
    Dave Calkins's Avatar
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    George, let me whisper in your ear.

    You said extended Cub gear. 3"?

    I'm thinking 35's or at least 31's on that 3" gear.

    I've always wondered/dreamed what a Husky would do with "better" 3-point AOA.

  16. #56
    aktango58's Avatar
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    Does someone have a set of 35's to sell?
    I don't know where you've been me lad, but I see you won first Prize!

  17. #57

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    We fly a Husky on extended gear with AO and another Husky without, both on 31's, and much prefer the Cub extended gear for off airport operations. (It is slower in cruise by about 5 knots.) We tried 35's and didn't like how they felt on our AO equipped Husky -- really hurt the climb rate, added 40 pounds, and took away the snappy Husky feel on a sea level takeoff (making it feel like you were in Idaho).

  18. #58
    mvivion's Avatar
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    Iceboat,

    Aviat Husky model A-1B after 2005 had the "new wing", with extended flaps, deeper chord ailerons, and no aerodynamic counterbalances. The "C" model Husky came out a bit later. Point is, some B model airplanes have no aerodynamic counterbalances, and none of the C's do.

    MTV

  19. #59
    Hyrdflyr
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    lw-2500s

    check your pms

    Hyrdflyr

  20. #60
    Wayne Mackey's Avatar
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    ski

    Would someone post the phone number for the aero ski outfit. Thanks
    Wayne

  21. #61
    irishfield's Avatar
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    320-346-2285

  22. #62

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    RF ski update. Parts received from Europe. More bent rod ends found on a Cub, after previously replacing bent rod ends.

    Right now, we are stuck at step one of the recognized ten step process for solving these sort of problems.

  23. #63
    aktango58's Avatar
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    George,

    I have never seen these skis in life, nor have I watched them work... but I thought of this looking at the pics you sent:

    First: are you or anyone putting skis down while on the ground, thereby stressing the little hydraulic ram? (it may say it can do it, but that ram is little).

    Second: the connection between the ram and the black mount has a slide slot cut in it... my guess is it needs that for an 'over cam' situation. If so I would take a guess that you might have a couple of issues happening- the slot if warm will build ice inside, restricting movement, (pull out of hanger, fly in warm weather, low alt warm to glacier landing) or flying in overflow you can build ice inside; the other would be building snow/ice under or around the ram so it's movement is restricted.

    Third: the slit/bolt set up if not connected with a really good bearing surface will tend to bind, even if you think you have grease (grease collects water-see above) If it were my set up I would want some sort of UHMW bushing that would be slippery no matter what, and change it out every 100 hours... That slot is very small for the conditions you are asking it to work in...

    Again, I am just looking and thinking about some of the machine issues I have had with hydraulics over stressing the equipment around it, or destroying itself.

    One quick check is to see if the slot is bearing surface smooth and flat or has gouges or bumps. If not smooth and flat that would indicate a problem

    Good luck, and keep us informed.
    I don't know where you've been me lad, but I see you won first Prize!

  24. #64
    Dave Calkins's Avatar
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    AkTango. The slot is not failing.

    The rod-ends are failing.

  25. #65
    aktango58's Avatar
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    Ok, looked again...

    Are the rod ends torquing up and down?

    These look just like the ones we use on sleds for steering... POS!

    My bet you could go to the sled shop and get new ones today....

    But,

    It is a weak link, do they need to have a complete swivel? I would think that it only needs to rotate around the fittings, making the whole rod end idea obsolete...

    But if you must use them, build a block to thread the rod end through and contacts tightly to both the arm and around the circular part of the rod end. Doing adjustments suck, (bench grinder) but it supports the ends.

    a 1/2" or even 9/16" bolt was not made to take a 2,000 lb plane laying on the end with 2-3" arm out!

    I would build a torque block with a bushing that bolts to the arm...

    I can build you some this week if you send size.
    I don't know where you've been me lad, but I see you won first Prize!

  26. #66
    Dave Calkins's Avatar
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    Aktango, the molded carbon fiber retract arms on those skis are a thing of intense beauty. It's not likely that George or these other guys will bolt up an Alaskan-rigged solution to their very nice and expensive skis, unless it is condoned by the ski manufacturer.

    The rod-ends are an Airbus part, so they oughtta have some QC in place and the system should be designed so they are able to take the loads.

    My guess at the failure mode is this: When the wheel retracts, the tire is being pressed against the retract arm, actually it is being squeezed, HARD. This is a fact from my observation of the skis in operation. I can imagine that the force of the tire pressure, which in the geometry of this system INCREASES when you land and put weight on the skis..............the force of the tire is caused by the retract arm and is 90 degrees to the rod-end shank. I can see this force breaking the rod-ends. I can see this as the cause. However, I did not inspect the broken rod-ends, and don't know the actual failure "direction". I am not involved in installing or rigging these skis, but was present at various stages of the installation on an A-1B.

    Maybe George M. will let us in on the direction of rod-end failure. Bummer for sure, as good ski-flying is to be had if the temp's here raise another 10 or 20 or 30 degrees F.

    DAVE

  27. #67

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    We have three different maintenance guys working on this, and bent rod ends on each of the three planes with the skis, including repeated failures on the same plane. This is with just a few hours, flown light, and in very benign snow conditions. There is no one thing we can identify as causing the problem -- basically the rigging right now isn't strong enough to stand-up to long term use.

    The skis are absolutely beautiful, have fantastic wheel clearance, are lightweight, and as Mike V reported previously, perform great. That said, the rigging is more like what you would expect on an experimental, and since a product is only as good as its weakest part, we need to get support from the manufacturer to redesign the rigging. That is what I was referring to as hung up at step one in the ten step process -- and step one is admit we have a problem. If we can resolve this, and we certainly want to, this will be a fantastic ski that will be very successful in Alaska.

  28. #68
    aktango58's Avatar
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    Dave,

    I will bet that the rod ends, airbus or Polaris, are made the same, with same QC. Bottom line is that they were never designed to hold 1,000 each 90 degrees in shear, then have them sticking out for a lever to bend!


    As far as an "Alaskan-rigged solution", seems most of the planes people on this site own have thoes: removable seat bar, extended baggage, HD gear, Extended Gear, boer prop....

    But because I suspect that you are referring to a cut to shape, beat to size, shim to fit.... check out my photo album and see my project I just finished- a tool specifically made for producing some parts I need!

    George,

    If you have one good rod end, mount it in a steel block and do a pull/push test in a press and see just how much pressure the thing will hold in truth

    my bet if you tied a Husky down with the plane's weight in shear on these' they would bend in a wind storm...

    But I am far away and taking wild guesses.

    Keep us informed!
    I don't know where you've been me lad, but I see you won first Prize!

  29. #69
    mvivion's Avatar
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    George,

    Sorry, but there is nothing wrong with the SKI rigging that I ever saw. As I noted earlier, I put a lot of hours on a set of these skis in northern Alaska, and in VERY deep snow at times. We also had the airplane on McKinley with the skis. Those skis have been beat around a good bit, and they have not had problems with them at all. They work.

    Furthermore, there are a number of sets of these skis flying regularly, for several years, in Europe, on Huskys, Super Cubs and other aircraft.

    When we put the skis on our Husky, we changed to the Aviat "ski landing gear", which was designed for the Aero 2800 skis. That's what Thomas is using in Europe as well. Have you considered that the reason you folks are experiencing failures is the attach hardware you're using?

    It seems the only failures on these skis noted to date is where they are being mounted to aircraft with ATTACH fittings made and installed locally in your part of the world. What you have described SOUNDS like an alignment problem to me. That is, alignment of the attach points, not the ski actuators.

    But, I may be waaaayyyy off. It's hard to visualize these mechanisms remotely.

    In any case, I can tell you that while the attach mechanism on those skis does LOOK a little light, it can and will take a beating. I've turned those things around in very deep snow really tight, and nary a whimper.

    I hope you get this figured out soon. Good luck.

    MTV

  30. #70
    aktango58's Avatar
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    All good points Mike,

    Did your skis use the same rod ends? If so, I want some for my sled's steering!

    I would bet with all of us where the planes are, and three cases of beer, a bunch of stakes on the Barby we could get this sorted out after the third beer run!
    I don't know where you've been me lad, but I see you won first Prize!

  31. #71
    Dave Calkins's Avatar
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    Tango, I meant no intent against your jury-rigging skills

    What I meant is that we are talking about a very expensive European-manufactured product, the designer of which is unlikely to 'approve' what the best engineers on the West coast or "North coast" of america (lower-case 'A' for european-snobbery-effect) are able to conjure. Notice that George M. said that first we have to admit there is a problem? I'm sure the manufacturer is as bummed as George that all is not in gleaming perfection. I hope this is quickly resolved.

    Mike V., were you guys running the carbon-fiber arms?

  32. #72
    aktango58's Avatar
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    No offence taken Dave!


    usually I defer to the guys that really know what is going on in my plane. But when it comes to hydraulics and linkage breaking, I take great glee in finding the trouble, call it a mental defect! :P

    If the units are the same as Mike used, I would guess that alignment is the problem. If ANYTHING has changed.... you know the drill.

    I do have a hard time believing that those little rod ends hold a plane!

    Another thought- could the tires have a different depth of tread causing more pressure?

    well, off to the shop now, have more parts to build.... Need anyting?
    I don't know where you've been me lad, but I see you won first Prize!

  33. #73
    mvivion's Avatar
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    Dave,

    Yes, same arms, same rigging. Different gear.

    MTV

  34. #74
    aktango58's Avatar
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    Don't they make cub gear with the tabs welded on for Aero skis?
    I don't know where you've been me lad, but I see you won first Prize!

  35. #75
    Dave Calkins's Avatar
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    I was wrong about the failure mode having anything to do with the squishing of the tire.

    Apparently the failure is occurring as the a/c is being raised from wheel to ski. At that point the weight of the a/c is supported on the shank of the rod-end at about a 90 degree angle and the rod-ends aren't up to it. One of the failures occurred in the hangar during a retract test. Yikes!

    Mike, one of these sets is on an A-1B with an "Aero-gear" as manufactured by F.Atlee Dodge. I'd be surprised if Atlee's screwed up all the bracket/tab/stub fabrication. Mystery's!

    DAVE

  36. #76
    Crash's Avatar
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    Landis Airglass was sold a few months back to the "son" of Northrim Bank.

    I've talked to the new owner and he is moving forward as fast as he can with an LW-3000 version (for Cubs and Huskys) of their Cessna 180/185 LW-4000.

    Hands down, the LW-4000 is THE ski to have on a C180/185 or Found Bush Hawk.

    In the future I feel the LW-3000 will do the same thing to the Cub/Husky ski market.

    Talk is of the ram being electric, so no hydraulic pump and plumbing.... wouldn't that be nice.

    Crash

  37. #77
    irishfield's Avatar
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    Quote Originally Posted by Dave Calkins
    I was wrong about the failure mode having anything to do with the squishing of the tire.

    Apparently the failure is occurring as the a/c is being raised from wheel to ski. At that point the weight of the a/c is supported on the shank of the rod-end at about a 90 degree angle and the rod-ends aren't up to it. One of the failures occurred in the hangar during a retract test. Yikes!

    Mike, one of these sets is on an A-1B with an "Aero-gear" as manufactured by F.Atlee Dodge. I'd be surprised if Atlee's screwed up all the bracket/tab/stub fabrication. Mystery's!

    DAVE
    This would suggest to me that the skis where designed to be re-postioned in flight only !! ??

  38. #78
    Dave Calkins's Avatar
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    Quote Originally Posted by irishfield
    This would suggest to me that the skis where designed to be re-postioned in flight only !! ??
    Apparently these same a/c have not had failures when retracting/extending in the air only. D

  39. #79
    irishfield's Avatar
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    Have a bad feeling that's the intent. So many figure the guy wants to leave pavement.. go play in the snow and come back to pavement.

    Not the real world of wanting to roll out of the hangar to snow... reposition.. up over the snow bank and go play. Come back.. slide over the snow bank and reposition wheels down.

    I don't think you're supposed to repositon AWB's on the ground either are you?

  40. #80

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    Dave, we only cycled our skis in the air, and ended up with a bent rod end.

    Mike, Atlee Dodge welded the tabs on one Cub and the Husky, and our installer did our tabs on Cub/AO gear. He is the same person that did STC one of the AO gear on the Husky, and absolutely knows what he is doing. Out of curiosity, did you ever pull your rod ends and check them to see if they were bent? Are those skis still flying? Are you aware of any other sets of those skis flying in Alaska that would represent another data point on durability?

    We love the skis and hope to resolve this soon. We are working with the manufacturer on a fix.

    Crash, compared to the LH-4000 skis, these have MUCH more ground clearance when taxiing -- important on rough gravel strips.

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