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Thread: My SQ2 Mods

  1. #41
    8GCBC's Avatar
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    Quote Originally Posted by mvivion View Post
    Phil,

    The zip ties with a metal tab are sold at electrical supply places. Don’t sweat the first flight, you aren’t the first to tackle ski flying on your own. Just take your time, think things through, and don’t be afraid to shut down get out and push the tail around.

    Have fun!

    MTV
    Tight maneuvers on surface...skis have a disproportionately long "Arm" of physical leverage...

    ...cub style axles don't absorb lateral torsion well. I have seen pictures of the welds failing. But, I'm sure it was from totally neglecting common sense. Opinion: I like cub gear, just say'n

    My insurance company said go ahead and fly the thing. I said "really, no sign off, no freeking dual"? So I taught myself.
    Last edited by 8GCBC; 11-20-2017 at 02:43 PM. Reason: Teaching "myself" grammar:-)
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  2. #42
    mvivion's Avatar
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    Yes, a dollop of common sense is required here. You’re putting a lot of torque on those axles, so I push the tail around in stages, and between each stage, I walk around and give each ski toe a light kick to get it to turn.

    MTV

  3. #43
    Barnstormer's Avatar
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    So I'm back from my first ski flight, what a hoot! I'll put a video together but I wanted to share two things now. First right out of the hangar I managed to get stuck (see pic)- ha ha ha I know. No amount of power would move me forward (it is a good snow blower though, right down to the grass), reminded me of getting stuck on that island. Anyway not to worry I just bought this really cool light weight avalanche shovel from REI (see pic). Once I looked at how much snow I needed to dig away the avalanche shovel was not quite as cool. Fortunately I had a real snow shovel in the garage. Anyway got her flying and landed a number of local float plane lakes. Guess tomorrow I'll be shopping for a big plastic snow shovel for the plane. What fun I had!

    IMG_4064.jpg

    IMG_9808.jpg
    Phil Whittemore
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  4. #44
    mvivion's Avatar
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    Out-friggin-standing! Let the fun continue.

    MTV

  5. #45
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    Phil, copy this photo and tape it in plain view on your wing root interior fairing. Skis are a blast till the fun stops, then they really suck. Blasts of power will blow the tail atound 90% of the time, the other 10% sometimes looks like this



    Have fun, be smart if given the choice but being ballsy works most of the time

    Glenn
    "Optimism is going after Moby Dick in a rowboat and taking the tartar sauce with you!"
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  6. #46
    BC12D-4-85's Avatar
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    How well do the ski brakes work?

    Gary

  7. #47

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    Quote Originally Posted by mvivion View Post
    Yes, a dollop of common sense is required here. You’re putting a lot of torque on those axles, so I push the tail around in stages, and between each stage, I walk around and give each ski toe a light kick to get it to turn.

    MTV
    More than once I've witnessed landing gear failure caused by the pilot pushing the tail to turn the aircraft on skis. The inside gear gets torqued until something lets go, usually the bolts attaching the axle to the gear leg. The noise just sends a chill down your back.

    RK
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  8. #48

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    [QUOTE=landed a number of local float plane lakes. Guess tomorrow I'll be shopping for a big plastic snow shovel for the plane. What fun I had!
    [/QUOTE]

    Is the ice thick enough already?

  9. #49
    Barnstormer's Avatar
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    Quote Originally Posted by BC12D-4-85 View Post
    How well do the ski brakes work?

    Gary
    Don't know yet, we got a fair amount of snow (6"-12") that has covered the ice.
    Phil Whittemore

  10. #50
    Barnstormer's Avatar
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    Quote Originally Posted by Randyk View Post
    Is the ice thick enough already?
    A lot of the lakes around here have 5" of ice or better, some have almost no ice- no idea what causes that- I'm still learning about winter.

    A lot of guys are landing the lakes on bushwheels still, saw that today.
    Phil Whittemore

  11. #51
    AK_Logan's Avatar
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    Quote Originally Posted by Barnstormer View Post
    A lot of the lakes around here have 5" of ice or better, some have almost no ice- no idea what causes that- I'm still learning about winter.

    A lot of guys are landing the lakes on bushwheels still, saw that today.
    Figure 8s! Try not to stop in fresh snow try to park in your tracks makes getting moving so much easier.
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  12. #52
    BC12D-4-85's Avatar
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    Phil asked about lakes freezing...

    Time of ice formation is often determined by lake volume and depth plus ambient surface air temps and sky conditions above. Those lakes with more water volume and greater depth form ice later as it takes longer for them to ultimately cool. Water typically cools at the surface until it's around 39F which is the temp point of max density for fresh water. As its cools further the dense 39F surface water settles to the bottom, and the then less dense surface water cools further until near 32F.

    The lake eventually stratifies by temps with near 32F less dense water on top over slightly warmer 39F dense water on the bottom. Snow crystals cool the surface and can provide a source for ice formation, normally starting near the shore in shallow water or areas protected from the wind. Cold calm air and clear skies above speed the process. Heat loss is enhanced under no wind and clear skies due to long wave infrared radiation from the water.

    Once ice forms that layer expands even further becoming less dense than liquids just above freezing below so the ice layer floats and insulates. A life experience is listening to new ice form..it booms and cracks telling us winter has arrived and all is good and getting better. Snow and clouds can screw up the ice but that's a discussion for later.

    Rivers form floating and rotating ice pans usually along shores first then they collect and cover the surface. Ice also forms and collects on river bottoms (frazil ice). Temps are similar top to bottom but mixing can lower them overall towards freezing. If they freeze to the bottom then the water from upstream can flow over the top and form large Aufeis fields that spread over nearby terrain.

    Gary
    Last edited by BC12D-4-85; 11-21-2017 at 11:42 PM.

  13. #53

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    Don't buy plastic!! Get a aluminum shovel, the plastic will brake when you need it most. It is nice to be light but really sucks to be stuck and cold!!!
    DENNY
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  14. #54
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    Quote Originally Posted by AK_Logan View Post
    Figure 8s! Try not to stop in fresh snow try to park in your tracks makes getting moving so much easier.
    Park in your tracks, and stop for a moment, then slide forward a ski length, stop, slide forward again, THEN shut down. Skis warm up from the friction of the snow, which is one of the reasons that they freeze down. By stopping, moving, then again, you’re letting the snow cool the ski bottoms.

    Its not much but it helps.

    MTV
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  15. #55
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    Quote Originally Posted by mvivion View Post
    Park in your tracks, and stop for a moment, then slide forward a ski length, stop, slide forward again, THEN shut down. Skis warm up from the friction of the snow, which is one of the reasons that they freeze down. By stopping, moving, then again, you’re letting the snow cool the ski bottoms.

    Its not much but it helps.

    MTV
    I have never heard the stop and then move again. It makes perfect sense tho. Usually you've been sliding for 3,4,500 feet or more to get back to your track.
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  16. #56
    RaisedByWolves's Avatar
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    MTV im sure us low time ski pilots would love to hear some hints and or stories, maybe in its own thread

    Tom
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  17. #57
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    Like glenn said, it’s fun until it isn’t. Haha


    Sent from my iPhone using Tapatalk
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  18. #58
    cubpilot2's Avatar
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    Quote Originally Posted by RaisedByWolves View Post
    MTV im sure us low time ski pilots would love to hear some hints and or stories, maybe in its own thread

    Tom
    Tom
    There is a separate Forum for Ski Flying here that is chock full of tips and “war stories” of ski ops.
    Ed
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  19. #59
    55-PA18A's Avatar
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    Quote Originally Posted by DENNY View Post
    Don't buy plastic!! Get a aluminum shovel, the plastic will brake when you need it most. It is nice to be light but really sucks to be stuck and cold!!!
    DENNY
    Pretty hard to beat a No. 12 or 14 poly grain scoop. https://www.amazon.com/True-Temper-D...000DCOPHE?th=1
    They're made to move material, not scrape snow down the sidewalk. Surprisingly durable. Ice doesn't build up on it from the snow as you're shoveling. Doesn't have a metal edge that will slice up everything in your baggage.

    Jim
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  20. #60

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    yes you are correct. They are the slickest shovel to use. I love em.

  21. #61
    BC12D-4-85's Avatar
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    Shovels...ahh getting old when experience tells us to drill some holes in them so water can drain away when shoveling wet overflow on lakes from under stuck planes on skis. Had a C-185 on AWB 3600's submarine one ski under a foot of snow and a layer of ice above a foot of water and the main lake ice cover. Chopped and dug a trench until I could drive it up on the lake's shore and turn it around. Shovel had holes and an axe was handy. The two idiots onboard had forgot the snowshoes in the truck but bunny boots full of water saved the day.

    Gary

    Edit: We shoveled the wet snow away and cut trench in the thin upper ice layer as noted as the left ski and tail ski were stuck in it. Then moved the plane slowly in steps until near the shore it got thinner water. We filled the trench with snow and drove the plane back up on top to the shore. Shoveled bare spots on the dry shore, dropped the wheels, and turned the plane. Pumped the skis down and left for coffee and pizza. I had drug the lake three times hard before landing (three wide tracks next to each other) but no overflow showed until we slowed down.
    Last edited by BC12D-4-85; 11-21-2017 at 09:33 PM.
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  22. #62
    Barnstormer's Avatar
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    Beringer Wheels & Brakes. Finally got around to installing them. 4+ lbs weight savings on each side and significantly better braking. And I finally have myself a parking brake.97da94069ad407ee28128092.jpgb83524d317b04e783a89ed36.jpg2fd91569bc59342286b8a9c3.jpgefcd831535aabc6b98226f0c.jpg
    Phil Whittemore
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  23. #63
    Barnstormer's Avatar
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    New TK1 Gear (6x3) and shocks

    Phil Whittemore
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  24. #64
    BC12D-4-85's Avatar
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    Looks nice Phil. What type of fitting attaches the lower shock strut to the landing gear? Fixed threaded end or flexible Heim joint? Any safety cables planned? If you grab the front of the skis while elevated can you twist the gear?

    Gart
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  25. #65
    RVBottomly's Avatar
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    I like seeing that gear. I'm curious about the three bolts and the extra bolt holes in the axle assembly. I see one attaches to the shock assembly, but what do the other two do, allow the axle to be adjusted width-wise?
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  26. #66
    www.SkupTech.com mike mcs repair's Avatar
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    Quote Originally Posted by Barnstormer View Post
    New TK1 Gear (6x3) and shocks

    kind of wimpy in the twist area of any modern gear at the bottom.... must be built based off of original gear blue prints, instead of looking at modern gear/lessons learned/multitudes of planes bent from gear failures.... prop strikes are expensive, so are wings......

  27. #67
    Barnstormer's Avatar
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    Gary, fixed. I haven't used safety cables in the past with 700 hours on the first version of these and thousands of off-airport landings, but I have very little time on skis and know little about the loads they create. I actually have been wondering if instead of safety cables I could use Amsteel- no stretch and super strong- and very light.

    RVBottomonly, the axle is separate from the landing gear, so not strength loss from being welded to the gear. The axle slips into a collar and the bolts retain it. Brilliant.
    Phil Whittemore

  28. #68
    BC12D-4-85's Avatar
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    Phil as you have seen tires flex and skis don't. Different loads on the gear is obvious.

    For CAR 3 aircraft like Cubs:

    .§ 3.257 Supplementary conditions for

    skiplanes. The airplane shall be assumed resting
    on the ground with one main ski frozen in the
    snow and the other main ski and the tail ski free
    to slide. A limit side force equal to P/3 shall be
    applied at the most convenient point near the tail
    assembly, where P is the static ground reaction
    on the tail ski. For this condition the factor of
    safety shall be assumed equal to 1.0.

    For Part 23.505

    135. What is the typical method for determining the load factor for a ski installation?
    a. A ski installation should use a load factor determined by either of the following two
    methods:
    (1) Perform drop tests, with skis installed, on a surface simulating frozen hard- packed snow or ice; or
    (2) Use a conservative formula (see SPECIFICATION—Aircraft skis, National Aircraft Standards Committee, NAS 808, paragraph 5.1(a)).
    b. Ski installation factors should include consideration for fittings, tubes, axles, nuts, bolts, etc., which attach the skis to the fuselage. Ski-gear loads normally run about 115 percent to 125 percent of wheel-gear loads. Also see 23.737, Skis.

    23.485 Side load conditions (like tires I assume)
    (Amendment 23-45)
    131. Is there any policy available on this section as of January 1, 2007? No.

    For Experimentals you're on Mars. Enjoy the view.

    Gary

  29. #69

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    Quote Originally Posted by Barnstormer View Post
    Gary, fixed. I haven't used safety cables in the past with 700 hours on the first version of these and thousands of off-airport landings, but I have very little time on skis and know little about the loads they create. I actually have been wondering if instead of safety cables I could use Amsteel- no stretch and super strong- and very light.
    .
    There was some discussion earlier on synthetic safety cables.
    these were made out of 3/8” Dyneema and performed very well when shock loaded.

    Edit: 1/4” Dyneema below photos.
    0DFF5DB3-B615-4794-A84A-39C3455B5E89.jpg
    723D9587-743E-4CAA-9780-06140F9224BD.jpg
    Last edited by Oliver; 02-21-2019 at 12:02 PM.
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  30. #70
    Barnstormer's Avatar
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    Thanks Oliver and Gary.

    Here is what I got from Tony: "I doubt you could twist the gear leg enough to create an issue at the clevis. Interesting idea though. I’ll have my guys do some computer modeling and engineering on the subject and see what the calculator says. Generally rod ends suck. We only use them when there’s no other option. The threaded clevis we use is 4140 chromoly then heat treated to 50 rc and nickel Teflon coated. It’ll bend almost 90 degrees before breaking."
    Phil Whittemore
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  31. #71
    Jonnyo's Avatar
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    Quote Originally Posted by Oliver View Post
    There was some discussion earlier on synthetic safety cables.
    these were made out of 3/8” Dyneema and performed very well when shock loaded.

    Edit: 1/4” Dyneema below photos.
    0DFF5DB3-B615-4794-A84A-39C3455B5E89.jpg
    723D9587-743E-4CAA-9780-06140F9224BD.jpg


    Oliver,

    What size is the rope in the photos? 3/8 or 1/4?

    When I splice nylon or poly rope, I use a fid and bring the tail in and out, on opposite sides of the main line. The tail is inside for 2 inches and then outside for an inch. I repeat this twice and leave the tail inside. The tail never seems to "creep" out when going from slack to taught 10,000 times. Maybe overkill, but we lost a skiff on the way to Seattle that just had an internal splice. One morning I looked out on wheelwatch and there was only a rope back there. The sharpie mark on the rope, added for cut measurement, was still there. The splice had crept open. I see the black thread sticking out. Is that a "stop" ?

    With the splice out in 90 mph, turbulent air, and never held firm by strong tension, I wonder if it might loosen up?

    Thank you for the post and the 2, excellent photos.

    Jonny

  32. #72

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    Jonny,

    Rope is 1/4”
    You can “lock” the splice as you described, not sure if it compromises the overall strength of the splice. Might be tough to do if there’s hardware attached to the other end of the line, though I’ve heard it’s possible.
    Other options are to whip it, or lock it with a few stitches. (black thread in previous photo)
    you are correct though, it will defiantly work itself loose otherwise.

    I’ve been thinking to do some more experimenting when I get some time.
    Thinking to do some back to back pull tests substituting 1/8” 4130 against 3/16” stainless currently being used as attach points.
    Last edited by Oliver; 03-15-2019 at 09:57 PM.
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  33. #73
    Jonnyo's Avatar
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    Quote Originally Posted by Oliver View Post
    Jonny,

    Rope is 1/4”
    You can “lock” the splice as you described, not sure if it compromises the overall strength of the splice. Might be tough to do if there’s hardware attached to the other end of the line, though I’ve heard it’s possible.
    Other options are to whip it, or lock it with a few stitches. (black thread in previous photo)
    you are correct though, it will defiantly work itself loose otherwise.

    I’ve been thinking to do some more experimenting when I get some time.
    Thinking to do some back to back pull tests substituting 1/8” 4130 against 3/16” stainless currently being used as attach points.




    Oliver,

    Do you have a strain gauge ? It would be extremely interesting to get some "data" on the results. On my tabs, so that I can go as light as possible, I use the thinnest size that has shown to work in the past and then run a TIG bead around the holes, on the flat topside. If you look at your picture of the tabs that broke, they don't stretch/brake in the middle; where the meat is, it's out on the thin edge, by the hole. Some 70,000 psi TIG rod has always -- seemed, to help that out. Retempering a small tab is easy. Having a thicker edge for the bolt or cable thimble to ride on, also --seems, like a good idea. It would be great read some thoughts from some Engineers.

    Thanks again for the great photos !

    Jonny

    Let me know if you get spooled up for a test. I would contribute some $ to that.

  34. #74
    skywagon8a's Avatar
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    Quote Originally Posted by Jonnyo View Post
    If you look at your picture of the tabs that broke, they don't stretch/brake in the middle; where the meat is, it's out on the thin edge, by the hole.
    That break appears to have elongated the hole which stretched the metal at the end thus the tearing action. Have you thought of doubling up on the hole with a washer just welding around the half of the circumference towards the end of the strap?
    N1PA

  35. #75

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    Unfortunately I don’t have a strain gauge,
    i, rather archaicy, pulled on hardware to the point of failure.
    metal was the weakest link. The amount of force applied may have well exceeded what’s necessary to save a plane with gear failure.

    cunclusion so far is that Dyneema exceeded expectations and can be ruled out as the weak point.
    if there’s more interest in proceeding, maybe start a new thread and bounce some ideas around.
    Thanks
    doug

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