Denalipilot; Hmmmm...... good point, didn’t consider that. I went 3” on either side and 2” on nose and tail. I’ve seen as much as 4” overhang. With the dollies, did you mean the lower hole on the pedestal? Dollies are on the list, but not anytime soon.


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I don't hold a stake, but what is the basis of elegibilty for the plastic bottoms? Are they part of the original design and STC? What basis is there for increasing the size of the ski with the overhang? Any limits?

The magic carpet suggestion for under the skis while parked is one I'll remember and share. Great idea.

Wldlndfirefghtr wrote:Denalipilot; Hmmmm...... good point, didn’t consider that. I went 3” on either side and 2” on nose and tail. I’ve seen as much as 4” overhang. With the dollies, did you mean the lower hole on the pedestal? Dollies are on the list, but not anytime soon.


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Yes- meant to say the lower holes. The dolly has a pipe that inserts in it and a lever that cams over in a wheels-down position. Not that you need to own a set, but if you use a shop that has them then it might be a consideration.
-DP

Pinecone wrote:I don't hold a stake, but what is the basis of elegibilty for the plastic bottoms? Are they part of the original design and STC? What basis is there for increasing the size of the ski with the overhang? Any limits?

The magic carpet suggestion for under the skis while parked is one I'll remember and share. Great idea.

Good question. Most ski manufacturers these days incorporate UHMW bottoms. So, they’re generally viewed as part of the type design, though I doubt any of the older Skis address the addition of the stuff.

The industry and the FAA generally view the stuff as a protective, sacrificial coating that is designed to be replaced in the field.

I once inquired of the FAA whether I could legally replace the steel skegs on my Aero 3000 Skis with a UHMW strip of similar dimension, to help prevent freeze down. The response was that those are “wear strips” as opposed to skegs, and therefore, being sacrificial, can be replaced with a different, appropriate material.....ie: UHMW.

As to extending the size of the ski bottoms with UHMW, that seems to be a relatively recent phenomenon....like the last fifteen or twenty years, mostly in Alaska. I seriously doubt that there has ever been an “approval” for doing so, other than MAYBE a logbook entry. But, since skis don’t come with a logbook.....most ski rebuilds that I’ve seen were just done.

MTV

Well I figure I’d follow up from last years post. Thanks to all for the constructive input.

I tabled the skis last year as I ran out of time and the mostly lack of snow from what I remember.

Got rigging made finally and got them installed. Just waiting for the final paperwork and updated weight and balance to be completed so I can get out and explore. I got to taxi around and boy that was fun.

Can’t wait to get out with others and let the real education begin.






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Some installations run that front safety cable to the tab attached to the lower engine mount. Watch the spring ends and cable ends for wear. A little lube there can reduce that as the prop blast shakes them good.

Gary

Gary,

At 1st we were going to run the safety cables to the lower engine mount, but the mechanic liked running it through the spring in the event of a failure, thus containing the spring from shooting/flopping around.

We did put some anti corrosion stuff on the cables and springs.

Appreciate the info on what to pay attention too. Excited to get out but it seems like there can be high degree of risk if something goes wrong with the skis or rigging, not even mentioning the environmental factors.

Any additional words of wisdom!?

Thanks


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No wisdom (turned 73 today) and was a plus day and learned something worthwhile here. I can see where the safety cable would restrain the spring, and actually that's what we do on lesser airplanes like Taylorcrafts and Cubs.

I'd be careful with high cruise or descent speeds at first with those enlarged bottoms. The Aeros tip up at the front and hopefully they are rigged a bit nose up in flight as well. The rears are also enlarged so there may not be a problem due to more download aft of the pedestal to keep the tips up in flight. See if they demonstrate any tendency to tip down and stretch the springs under heavy air loads or quick pull-ups at speed. The safety cables will restrict the tip downturn but the sudden drag can be awakening. Test some in your expected range of speeds and pull-up G-loads.

A load of wet snow on top of the skis will change their inflight behavior. Shovel up some and see what it can weigh. Now you have a bigger shovel that weighs more. If you notice the buildup after takeoff again be cautious about speed and g-loads until you work it out.

I'd test some turning and convince yourself the extended sides don't catch and excessively drag the gear sideways. They are cupped up by nature but still there is a longer than stock bending arm out from the center tunnel that may tend to twist the ski some. Do some turning and watch the ski action before playing cowboy with snowdrifts around or if the skis submerge below a frozen snow crust and catch that layer with the exposed tips on top while turning.

Other than those tests it's a beautiful plane and setup so go have some fun!

PS: Carry a shovel and a rope winch plus ice screws in case you get stuck.

Gary

One more quick note. Some will turn down the ski axles to allow the skis to butt closer up against the end of the gear leg. Usually that's with solid aluminum axles on a lathe. It can reduce the tendency for the skis to twist the gear by having a shorter arm outboard of the axle attachment flange. Also use NAS high tensile strength internal wrenching bolts to fasten the axles to the gear on skis.

Gary

Your skis seem to sit fairly flat on the surface when parked. Are those "Lady Legs" on the plane? My old 170 had early 180 gear legs, which were a little stiff, and unloaded parked, the skis had some camber to them.

The angle of the skis on the ground affects the way the skis turn. As Gary says, do some turns in snow, going at it gently at first, and see how it likes to turn.

That's a lot of added bottom surface area, but as long as its good and stiff, should be fine.

What engine do you have? Ski planes LOVE power and wing. But, as Gary noted, carry a shovel (I carried an aluminum grain shovel in a Cessna...if you're gonna move snow, I want to MOVE some snow) and be prepared to use it.

If you get REALLY stuck, as in "this is gonna take a while stuck", consider building a fire before you start shoveling. And, if you're REALLY, REALLY stuck, build a fire, then a shelter for overnight FIRST, then go to work.

Consider taking a friend....but maybe not a real close friend. An old friend of mine moved to Alaska as a young game warden, back in territorial days. First winter, he went on patrol with a crusty old pilot/warden in a Stinson Gull Wing.....sorta huge airplane, on straight skis.

On their second stop, the got stuck and couldn't turn around. They shoveled, then the pilot told my friend "You take that rope tied to the tail, and help me turn this thing around". The pilot climbed aboard, and applied buckets of power and lots of rudder, while my friend got thoroughly blasted with chunks of snow, etc. Temp was -20.

Once they got the big beast headed the right direction, my friend saddled up, somewhat worse for the wear. He said the pilot turned to him and said "Well son, you now know that there are two kinds of game wardens in Alaska: Blasters and Pushers. You also know that it is indeed better to be a Blaster than it is to be a Pusher." My friend learned to fly the next spring.

You're going to get stuck every once in a while. Don't sweat it, just try not to break anything in the process. And, make sure that YOUR health is taken care of. Don't get frostbit or hypothermic in the process.

DRINK WATER!!! You get dehydrated FAST in cold, but your body doesn't communicate that need for hydration to you, like it does in warm weather. Drink water.....

But, most of all, ski flying is simply the most fun you can have in an airplane. Period. Enjoy it, take lots of pictures, and make some great memories.

MTV

MTV

The best analogy I have experienced is comparing aircraft ski size and shape to snowshoes. Go walk around in deep doodoo with short small light bear paw types, then do the same with long large flat trail models. Try to change direction and maneuver especially with snow (better yet wet snow) packed on top. Note the resistance to turns and how hard it is to make a turning trail with big shoes unless going straight ahead.

Now imagine doing the same with airplane skis in deep snow and pretend the ski gear legs are yours. It pays to be careful not to damage them.

One tech I tried to always do (now I pick my battles more carefully) was pack a landing zone under power before stopping for tea and cookies. Make several passes long enough to land and takeoff plus teardrop turnarounds at the end if possible. That sometimes took on a curved or S shape due to terrain but made ops easier than stopping then blasting and pushing like Mike describes.

Gary

Good idea, pack a landing zone under power before stopping this was ops normal for skis on the DHC6 plus it also allowed the skis to cool down and prevent adhesion.

Awesome information guys.

Gary,

I’m definitely interested in how’s it going to fly and will be cautiously anticipating. I naturally like to take things slow and fully aware that there are inherent risks, but I also don’t know what I don’t know. Good info on snow build up and effects, hadn’t considered that. I may make sure I bring a small auto brush to sweep off the snow from the skis.

I’ve done some winter camping in my younger years, so planning on having at least the bare minimum to be somewhat comfortable if I have to stay overnight and be able to dig out & secure the plane.

I’ve poured over what literature I can on ski flying/equipment/procedures (books, articles, word of mouth).

I have a DeLorme, that will be a key piece of equipment.




MTV,

I do currently have lady legs, O-300D (stock 145hp) and an 8040 prop.

I’ve read/heard about the tremendous force that are put on the ankles/axles. I definitely don’t want to man handle the aircraft, not that I could.

I’ve read/heard about making sure to drag/pack the landing area, looking for overflow and packing it down.

I’m sure it depends on site and condition, but is it best to just have a really long packed down strip (landing short and rolling into tracks) then you’re ready to just fire up and take off vs making your strip with the turns on either end (dog bone is what I have heard described)?

Once landed, heard about creeping forward to let skis cool down and not freeze. Is it best to dig snow out from under to keep air circulating and not freezing to bottoms?

I’ve heard it’s not ‘if’ but ‘when’ you get stuck.


My initial plan is to fly with a buddy that has some 170 ski time. If flying off airport; fly with others and if solo stick to ski strips and local lakes that have road access.

Appreciate the information all.


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Take a couple of pieces of "sacrificial" 2 x 4, place them under the tips and tails of the skis on shutdown

Wldlndfirefghtr wrote:Awesome information guys.

Gary,

I’m definitely interested in how’s it going to fly and will be cautiously anticipating. I naturally like to take things slow and fully aware that there are inherent risks, but I also don’t know what I don’t know. Good info on snow build up and effects, hadn’t considered that. I may make sure I bring a small auto brush to sweep off the snow from the skis.

I’ve done some winter camping in my younger years, so planning on having at least the bare minimum to be somewhat comfortable if I have to stay overnight and be able to dig out & secure the plane.

I’ve poured over what literature I can on ski flying/equipment/procedures (books, articles, word of mouth).

I have a DeLorme, that will be a key piece of equipment.




MTV,

I do currently have lady legs, O-300D (stock 145hp) and an 8040 prop.

I’ve read/heard about the tremendous force that are put on the ankles/axles. I definitely don’t want to man handle the aircraft, not that I could.

I’ve read/heard about making sure to drag/pack the landing area, looking for overflow and packing it down.

I’m sure it depends on site and condition, but is it best to just have a really long packed down strip (landing short and rolling into tracks) then you’re ready to just fire up and take off vs making your strip with the turns on either end (dog bone is what I have heard described)?

Once landed, heard about creeping forward to let skis cool down and not freeze. Is it best to dig snow out from under to keep air circulating and not freezing to bottoms?

I’ve heard it’s not ‘if’ but ‘when’ you get stuck.


My initial plan is to fly with a buddy that has some 170 ski time. If flying off airport; fly with others and if solo stick to ski strips and local lakes that have road access.

Appreciate the information all.


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You didn't note whether you've seen this: https://backcountrypilot.org/knowledge- ... ski-flying in the knowledge base on this site.

Might answer some of your questions.

When you installed the new UHMW bottoms, did you also replace the skegs with UHMW strips instead of steel? That REALLY helps avoid freeze down when parked.

Yes, come to a stop, wait for a moment or two, pull ahead, stop, wait, pull ahead and park. It seems ridiculous, but those skis sliding on snow create some drag, which creates some heat. You do need to cool them off before parking.

With UHMW skegs, I just shovel the snow out from under the fronts and most of the backs of the skis, leaving a "pedestal" of snow under the axle and another at the far aft end. Or, you can try to figure out how to lift a ski by yourself and insert a Two x Four. The technique I just noted works fine unless you're on really shallow snow on ice or>???

The Aero skis are pretty short and wide skis, so they actually turn reasonably well, compared to, say, Landes 2500s, which are longer and narrower. But, as Gary noted, you need to respect those axles and gear.

IF you do find yourself in a situation where you need to turn the airplane when not in motion, take the time to turn it just a tiny bit at a time, clear snow out from the sides of the skis, and very carefully turn the skis a bit at a time, then turn the airplane......I'm talking an inch or two max. Minimize the torque on those axles and gear legs. It can be done, but it's time consuming to do it right....

It's always great to be able to land, put down long tracks and not have to turn around. Unfortunately, it's not always possible to do so in every place you may want to go. That's when learning to turn the airplane pays off. Quick blasts of power, along with full nose down elevator to get the tail unloaded and hard rudder will usually do the trick, but again, be careful you're sliding forward as you turn to relieve torque on gear and axles.

MTV

I think I'll just shut up, "Or, you can try to figure out how to lift a ski by yourself and insert a Two x Four" goodbye.

Older Wiser Bush Pilot trick...lift-turn-kick or rock-repeat as Mike said. Once we push or lift the tail by hand and turn the plane give the front of the skis a side kick to straighten them out and ease off on the torque applied to the gear. It helps to pack snow near the skis or shovel the top off of bumps when doing this so they rotate easier. If they won't rotate then grab the wing strut(s) at the wing and bounce the wing and skis up and down hard. That'll un-weigh the skis briefly and they may bounce around like kicking them above. That'll also sometimes unfreeze them if stuck down with frost before flying.

Just like farming and feeding cattle...lots of work for some benefit.

Gary

MTV,

Yup got those links bookmarked. Also have stuff saved from the Alaska Airman’s Association and have the following two books; Self-Reliant Pilot by Bill Quirk and Notes on the Tailwheel Checkout and an Introduction to Ski Flying by Burke Mees.

I did replace the metal skeg with a UHMW. As it sits on the ramp, I was able to get 2x4’s on the front and tail to keep it off the ice.

Good to know about just shoveling in front and the tails when out in the field.


Gary,

Thanks for the tips on being super cautious on the axles and the additional tips on getting the bird turned.



Mapleflt,

I figured out a way and did get 2x4’s under the skis...by myself, on the ramp. Thanks for the encouragement.


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Mapleflt wrote:I think I'll just shut up, "Or, you can try to figure out how to lift a ski by yourself and insert a Two x Four" goodbye.

Hey, not at all, that's great advice. I just have a really bad back that I earned long ago, so I don't lift anything that I don't have to...

Putting something--a branch, a 2x4, or ???? under skis is a traditional means to keep the skis from frosting and freezing down. And, it works. If you have two people, it's easier, for sure, but can be done by one.

Me, I'm just lazy, and at least when on deep snow, it's easy to just clear the snow out from under most of the skis, and leaving them on pillars of snow.

But, your advice was just as good.

MTV

I always like to add this link to ski flying threads. It's a great read and a good learning experience I didn't have to go through. David is a great pilot and person. He learned the hard way!
https://yukonflying.com/DaveStorey.html