Crzyivan13 wrote:These are great problems to have.

Can't argue with that.

mtv wrote:It seems to me the most likely culprit to getting started out of your Hangar is that plywood.....I’d be afraid that trying to used a main gear attatchment to slide the plane into the Hangar would turn into a goat rope. Think tailwheel with a mind of its own, and tail going every which way.......$$$$$

I think you are correct, on both counts. I do have a long remote for the winch so I could hang on to the tail with the other hand...but it probably would be a hoot to watch.

courierguy wrote:I made up a pulling ring that bolts onto my main tail spring (in my case, a J-3 type) bolt...

I was thinking of something similar, replacing the big bolt with any eye bolt, if I can find one of the proper grade and thread.

Pusher wrote:Parking the skis on cheap carpet sleds helps...

Nice Pusher, thanks.

PA1195 wrote:Something like these wheel dollys make repositioning and frost free easier...

I've actually asked Carbon Concepts to build me a set, they'd made one for a customer that I saw when I was picking up my skis. Guess I'll see if I can hurry them along.


I went flying again yesterday. Beautiful sunny day. Two days prior the wind blew 20-30 knots and boy did the snow change. And being Thanksgiving weekend everyone came out to play. I saw lots of new ice skating areas, snow machine tracks, ice fishing huts and holes, four wheeler tracks, wheel plane tracks, and ski plane tracks. Also lots of areas of overflow and uncovered ice. Quite the change. The most radically altered lake you'll see in the video. All that white, fluffy, powdery snow that had been on the lakes sure made them look benign.

Lesson- nothing is as it looks.

https://vimeo.com/244556118

Great video! Wind can be our friend when it comes to overflow and sticky spots on the lake. Even though it roughs up the middle lake surface the wind's action compacts and redistributes the snow cover and creates ice activity. That in turn exposes water already on top and causes it to freeze, plus action will force low spots to fill with new upwelling water and level the hockey rink for later.

As long as snow covers the lake ice formation is slowed. Once compacted or exposed it grows deeper. There's always the undisturbed soft snow along shorelines to land on, but they can be covered with unfrozen water. Such spots tend to be traditionally wet from year to year.

When I started flying in the early '70s all this was a mystery and Old Timers could be hard to pry info from unless and until some of us paid our dues. Now it's the Info Age and we have a good chat online.

Gary

PA1195 wrote:Great video! Wind can be our friend when it comes to overflow and sticky spots on the lake. Even though it roughs up the middle lake surface the wind's action compacts and redistributes the snow cover and creates ice activity. That in turn exposes water already on top and causes it to freeze, plus action will force low spots to fill with new upwelling water and level the hockey rink for later.

As long as snow covers the lake ice formation is slowed. Once compacted or exposed it grows deeper. There's always the undisturbed soft snow along shorelines to land on, but they can be covered with unfrozen water. Such spots tend to be traditionally wet from year to year.

When I started flying in the early '70s all this was a mystery and Old Timers could be hard to pry info from unless and until some of us paid our dues. Now it's the Info Age and we have a good chat online.

Gary

Thanks Gary. This kind of info is a great help to beginning to understand what is going on.

Overflow can occur many places. Scary "little" patch as seen...

Just guessing but that bare spot in the snow looks to me like where the wind scoured the snow off; could be overflow but probably just bare ice. Better safe than sorry though. I hate overflow. Btw, since I haven't seen the comment yet, I was taught to stop short of where I intend to park and give the skis time to cool from the friction of sliding faster. Edge forward a couple times and then shut down and you will have less trouble with skis stuck in place.

8GCBC wrote:Overflow can occur many places. Scary "little" patch as seen...

That's bare ice. Look at the way the wind has flowed down that ridge, and scoured the snow off that spot. A classic example of air flowing downhill, and hitting a solid, and scouring it.

MTV

mtv wrote:

8GCBC wrote:Overflow can occur many places. Scary "little" patch as seen...

That's bare ice. Look at the way the wind has flowed down that ridge, and scoured the snow off that spot. A classic example of air flowing downhill, and hitting a solid, and scouring it.

MTV

It's water, see the little bergs?

8GCBC wrote:

mtv wrote:

8GCBC wrote:Overflow can occur many places. Scary "little" patch as seen...

That's bare ice. Look at the way the wind has flowed down that ridge, and scoured the snow off that spot. A classic example of air flowing downhill, and hitting a solid, and scouring it.

MTV

It's water, see the little bergs?

I doubt those are icebergs. I'd bet they are just embedded snow in the ice.

But, next time you're up there, land and check it out....

This is a classic example of overflow:



Note proximity to shore. The water may be flowing down off that hillside, and pooling under the snow cover..

MTV

I think 8GCBC's photo is of a glacial moulin.
It looks like the photo could have been taken above the glaciers of southeast Alaska in the summer. It's rare for them to form like that with the snow around them, but I've seen similar ones in the summer.
If it was a winter picture, I would agree with MTV that it was a frozen moulin.

AKclimber wrote:I think 8GCBC's photo is of a glacial moulin.
It looks like the photo could have been taken above the glaciers of southeast Alaska in the summer. It's rare for them to form like that with the snow around them, but I've seen similar ones in the summer.
If it was a winter picture, I would agree with MTV that it was a frozen moulin.

The pool of water was photographed at 06:00 LT 23-JUNE-2017, ELEV. EST 5.5K MSL, 32F, wind calm. Definitely water. SE AK, GBNP, Brady Glacier.

Appeared to be a possible exposed portion of a "Sub glacier lake" or Moulin:
https://en.m.wikipedia.org/wiki/Subglacial_lake
https://en.m.wikipedia.org/wiki/Moulin_(geomorphology)
https://en.m.wikipedia.org/wiki/Supraglacial_lake

Wikipedia image:


Another picture minutes before:

Probably no fish in that hole...move along. Still nice pictures.

Gary

The point of this thread is SKI flying. In that context, overflow (called slush in much of the upper Midwest) is generally considered to be free water, lying on top of ice and covered with snow.

The snow covering is what prevents this free water from freezing, even in very cold temps. And the snow covering is what makes overflow so dangerous to ski flyers, because you can’t SEE the water.

I don’t know many ski flyers who would intentionally land on obvious open water in any case. Let’s stick to the subject of the thread.

MTV

As Mike notes overflow or slush is where you find it but its presence can sometimes be detected visibly from the air. However it usually takes sticking a toe or ski in to really see what's where.

Some thoughts:

Heavy snow insulation over thin ice can be the Great Creator of overflow. Same for relatively warm temperatures after a cold spell. Thicker ice resists heavy snow cover but water can still eventually rise up through expansion cracks formed during freezing (drop an ice cube in water and note the cracking).

On lakes ice generally does this...it expands as it freezes raising the ice level in the middle of the lake. Or, if the lake's water level was high before freezing the level can drain some and the ice level can settle accordingly. Depends on the ambient water table of the surrounding terrain or if any outlets to the lake are flowing. Warm ground water from nearby terrain will flow downhill in soils and often has a brown color that taints and creates the overflow where it mets the lake. Or finally the lake ice level remains somewhat stable during the winter.

A problem is created when the ice along the shore eventually freezes to the bottom and can't rise or fall with that in the lake's center As it's fixed in place. Large "hinge cracks" form and water from the lake's center is forced up on that nearshore zone through the hinge and floods the area trying to reach an equalized level. Because snow depth is often deeper along shores protected from wind action that doubles the potential for problems.

Another source of surface overflow is bio-decomposition on the lake's bottom that creates gas (Mooo...like flammable methane: https://www.youtube.com/watch?v=oa3M4ou3kvw) which can open the visible spider shaped holes we often see in the snow's surface. The gas rises and can mix warmer water from the bottom with cooler surface water and melt ice. Some report that Alaskan Blackfish will also keep holes in the ice open in search of oxygen when levels of that dissolved gas decline during winter.

I used to drill near a maintained lake ice strip known for overflow to let the area flood while gone in hopes the overflow would eventually stop and freeze. Packing the snow with a sled and drag can compact the landing area and resist flooding compared with softer uncompacted snow nearby.

Gary

While I was down south for a few weeks for some appointments the temps up here rose and it rained a few times. Washed a lot of the snow away but not before my good friend akavidflyer came over with his snow machine and runway drag equipment and packed down my snow. Our temperatures are still swinging at or above freezing during the day and below most nights. Most local lakes are well frozen so out I went the last couple of days to learn some more about ski flying. Brave enough to actually stop the airplane on the ice! I'm doing this in baby steps.

So I put together this video, not doubt boring for everyone but me, but the end is kind of interesting when I come back and land.

I sure am enjoying the engine and wing performance of this colder air.

https://vimeo.com/248263530

Crosswind at the end? That's crazy stuff!

Still waiting for snow down here in Wisco so I can get out and experience my first skiplane adventure. Skis are on, apprehension is high, but I look at your progress and tell myself that I can do it, too!

~Chris

Phil,

I didn't see any indication of significant wind in that last landing. Methinks you REALLY need to get tailwheel steering hooked up again.

Otherwise, looks like you're figuring things out. Landing straight towards the (low) sun wouldn't be my choice, but that may be just the camera angle, not the pilot's angle. In any case, I presume you are inspecting all these landing zones from the air prior to touch. Nice thing about sunny days, particularly with low sun angle, is shadows are long, which really helps you to see irregularities.

As winter progresses, be very careful of sliding across snow machine tracks in deeper snow....after they set up, they can be magnum rough, and really tough on the gear.

Looks like really nice conditions in any case. Keep on having fun!

MTV

Great vid Phil...B.B. King rolls. Time to focus on landing and takeoff in your prior tracks...put it down there every time. Do it straight and in a turning curve to mimic bent river landings. Go to the end of your prior tracks and make a key shaped turnaround, then reverse course in your tracks and do same at the other end. Now you have a proven landing and takeoff strip and turnarounds for next time. Try to make the strip at least 3 ski patterns wide (first - center; rest to left and right) as it's hard to keep skis in a single track in deeper snow or in crosswinds.

Gary

Thanks Chris and MTV,

No wind on landing back at home. The first turn to the left might be partially equated to that part of the runway having a slight west to east downslope so a taildragger is naturally going to want to turn uphill. But the second and third are on flat ground. Part of the problem might be my tentativeness taxing to the hangar for fear of loosing directional control and not being able to stop before I hit something- so I'm going really slow which probably means even a short burst of power probably has more left torque power then rudder control. Before the rain and the runway getting the dragged I had 12" of powder which certainly helped slow the plane and give me some directional control. The current conditions are about 1 1/2" of frozen snow on top of ice. So not deep enough to give me directional control with the skis, but too deep for the grizzly claw brakes to do me any good.

Out on the lakes I was landing directly into the sun, the wind was about 8mph. But I did check the landing area from all angles before landing.

Fun stuff and sure different then wheels and brakes.

Thanks Gary. Headed south for Christmas but as soon as I'm back the tailwheel steering goes on and I'll start in on what you suggest.

Interesting about the lack of drag from the ski claws during your conditions. I've seen them being installed and assumed more effective braking and turning, but never tried them. I guess on ice they do work well.

One old technique prior to the Claw was to add an extended bolt to a bottom skeg and learn to live with that exposed head drag. Takes power to move but does slow the plane on ice...in snow it's not noticeable. In those conditions there's more drag and plowing from any ski toe-in. Once I went to plastic skegs control was iffy to sometimes non-existent at times in a crosswind on a polished snow or ice surface. The skeg(s) would lift the ski above the surface and the only contact point was the skeg(s).

Enjoy a warm Christmas,

Gary

Ice fisherman holes, actually the pile of chips they throw up and which then freeze, can be a problem, to put it mildly, and hard to see! I almost learned that the hard way.

I love the no bugs on the wind screen aspect of winter flying, so different from warm weather flying. NOT having brakes is so......interesting, and when back on the wheels this summer you will have a renewed appreciation of them.