ski plane technique

[Dave Calkins]

Well, no one has really told Jetech much about how to rig his skis beyond "hey look at the AC43.13"

Good advice!

However, when fabricating the aft check cable (the one that resists the spring or bungee and sets the allowable "nose-up" of the ski) The allowable limits in the AC43.13 are WAY WAY WAY too much. What you want is about 1.5 degrees of ski-tip "up" relative to the chordline of the wing.

If you put in like 5 degrees of ski-tip up, you will have gained nothing in ski performance over a 1.5 degree setting and will have slowed the a/c by A LOT.

As far as operations in flat light, spruce bows, or pieces of such, tossed out of the airplane make nice terrain markers, though they're heavy to haul around. Gunny sacks are another option. Black plastic trash bags are another, not so ecological option.

I sure wish SteveJ. had a way to make photo insertion a drag and drop operation, I have so many incredible ski-flying shots I'd love to share.

[Dave Calkins]

Okay, a couple hours with Lawn Dart's picture-posting tutorials and here we go. You really ought to check out the tutorials. WOW! thanks Cavy (Lawn Dart).

Here's just one nice shot, you can click it, and should, to enlargen it

[Dave Calkins]

Clicking on this one will link you to a larger, more detailed version of the one the above thumb links to. Once the large photo comes up, you'll need to click in thelower right hand corner to make it go full-page and beyond..



...thanks for bearing with my picture-posting practise. I love this shot. Hard to find better fun than this kind of flying!!

[ground loop]

Dave,

Just a wild guess, but is that picture on the hills south of Beluga Lake?

[Dave Calkins]

No, this is near Nellie Juan Lake. The "rolling hills" is actually galcial morraine covered with like 6 feet of snow. There are multiple LZ's in that area where a guy can get skiers on top of 4000 feet of vertical run, and pick them up at the bottom for another go. On a sunny day, there is no other place in the world I'd rather be than somewhere like this!

[cubflier]

Dave - I have determined that you need one more friend and that friend would be me! I've been looking for a drop off high and pick up low ski spot around the Palmer/Knik/Prince William Sound area and have yet to find an area that I can land at drop off and pick up altitude that has some real down hill ski challenge to it. There are plenty of drop you off high and spots or pick you up low but nothing with both. Any in this area that has both drop off and pick up strips has beginner grades to ski.

Jerry

[Dave Calkins]

Jerry, we'll have to get together.

[Dave Calkins]

Ground Loop. This is a bit nearer to Beluga Lake, kindof. Recognize it?



click thumb to enlarge

[jetech]

What do you guys do for tie-downs when you park for extended times off airport?

This is a very informative thread and I have learned quite a bit about ski flying that I did not know or even thought about.

I am particularly grateful for the rigging information since I plan to build my own skis and the only info that I have is the AC 43.13.

Does anyone have experience building skis? So far the plan is fiberglass with a replaceable UHMW bottom and some type of skeg. I am also looking at laminated wood with a plastic bottom and aluminum with plastic. Any advice in this area would be greatly appreciated.

[cubflier]

What do you guys do for tie-downs when you park for extended times off airport?

If you are on a lake you can auger a hole like you are ice fishing tie a rope to a 2' or so piece of 2x4 and shove it down the whole so that it turns and acts as a toggle. The ice will freeze over the hole and your plane will be secure. I've heard that other people chainsaw a slot in the ice to do in effect the same thing. If you are on solid ground I'm usually looking for small spruce/tree's to tie to or have even just used my snow machine on one side and a small tree on the other. If you are on a swamp like we have here in Alaska, Duck Bills drive in amazingly well since the frozen layer on top is normally not too thick.

Jerry

[coldNF]

Most of the time you do not need to tie them down in the winter because it is no fun to winter camp or do anything if is a windy spot. If you are in the trees or in a protected spot, the snow is deep and tie down is not needed. A ski plane in deep snow is not going anywhere. I carry ice screws (the ones that ice climbers use) to tie down in ice.

Steven

[Dave Calkins]

On ice, mountaineering ice screws are a good and simple method. Each takes about 20 seconds to insert. For each tiedown point I use 2 opposing screws and tie a line between them that the airplane gets tied to. So......... 2 screws for LH wing, 2 for the RH wing, and 2 for the tail makes 6 screws total. Quick, easy, secure.

For a season-long tiedown on a lake, 2x4's toggled through a hole in the ice is standard ops. around here. Note that ice grows from the top-down and melts from the top down, thus....your 2x4 will arise from the ice in the spring before the lake is thawed. Think about this for a second, you'll understand. You gotta keep your eye on it come spring or you won't actually be tied to much.

When in deep snow with no trees, etc. to tie to, I bury a "deadman". 12"x12" squares of 1/2" plywood with a hole in the middle and a rope thru the hole and knotted. Cheap, simple, quick. You have a shovel with you, right?

I've also buried pieces of trees, etc. Lately I've been thinking of using some 2"x2" for deadman, maybe 2 feet long. They would pack away a little tighter than the plywood.

The nice thing about screws and deadmen is that they are retrievable. If your camp is someplace else the next night, this is an important thing so you don't have to carry extras.

Jerry, I never thought of a duckbill for frozen swamp. Good idea, but I've priced duckbills in the last couple of years and someone at the duckbill factory is making decent coin! Good idea, though.

[Dave Calkins]

Jetech, you've asked a super-broad question with the design of skis.

Fiberglass, wood, aluminum? Pick one and move forward!

On the other hand, I'd suggest that you buy some used ones.

If you really gotta build your own, I'd suggest a laminated marine plywood deck and a tubular steel weldment pedestal. This is the easiest to design and build without reinventing the "ski".

If you can look around at enough photos, are competent at mixing epoxy for lamination, and have some fabbing and welding skills, you'll do okay with the TLAR method (That Looks About Right).

Good Luck, sounds fun, if you know what you're getting yourself into.

DAVE

[WIflier]

For everyone flying skis or who wants to fly them make sure your insurance covers you on skis. The only insurance company that I found with coverage on skis has been Avemco. If there are other companies offering coverage please post.

Si

[bushmaster]

Falcon

[Broknbone]

Here's a tip I learned this weekend. Carry a packable shovel. But make sure the shovel is bigger in diameter than your ice auger or your 4 year old son will drop the shovel through hole.

[Dave Calkins]

KIds!!! #@$^@#$^%#@$%

You've got me laughing Broknbone!

[mvivion]

Dave,

Great advice on the degree of nose up on skis. I too have never liked the real nose up on skis, and we've always rigged them at about 1 to 2 degrees max.

MTV

[high time cub]

Tim,

But, throwing out a traffic cone won't help you see the obstacles like a beaver house that can be virtually invisible in flat light.

MTV

http://www.theonion.com/content/node/47469

[haphogan]

I have a lot of time on skis, wheel skies, strait skis, Cubs, Aeroncas, 180, 185. conditions continue to change and are different in every area.

I find I continue to learn new things. when you stop learning is when you can get into trouble. Jerry has some excellent points.

When landing on a slight side hill in he Yukon north east of Eagle Alaska -48 deg F. water was flowing under the snow. When Strikeing this

[dalec]

On ice, mountaineering ice screws are a good and simple method. Each takes about 20 seconds to insert. For each tiedown point I use 2 opposing screws and tie a line between them that the airplane gets tied to. So......... 2 screws for LH wing, 2 for the RH wing, and 2 for the tail makes 6 screws total. Quick, easy, secure.

Dave

I bought a really cool little gadget at REI that aligns hole for ice screws so that I can slip a piece of webbing or rope through, don't have to carry or purchase near as many ice screws that way

[haphogan]

Ski flying is always a learning experience. I see my comment when landing north east of Eagle Alaska on a slight side hill at -48 deg F. flowing water under the snow surface was cut short. The result was the skies iced up and it took 5 hrs to remove the ice. Taking off after dark to return to camp.

possibly a good ski drag would have prevented this problem

[haphogan]

the ice screws sound like an excellent idea. the little gadget for aligning the hole sounds good as well. My son lands on the ice and snow from the south pole to the north pole with twin otters and turbine powered DC3s.

He informed me they use many different methods as well as ice screws and some times with the winds they require several screws and Herc Straps.

I told him about the gadget for aligning holes and ha asked for some information on it. I would appreciate the information for him.

[dalec]

the ice screws sound like an excellent idea. the little gadget for aligning the hole sounds good as well. My son lands on the ice and snow from the south pole to the north pole with twin otters and turbine powered DC3s.

He informed me they use many different methods as well as ice screws and some times with the winds they require several screws and Herc Straps.

I told him about the gadget for aligning holes and ha asked for some information on it. I would appreciate the information for him.

http://www.blackdiamondequipment.com...ce-screw-guide

[haphogan]

Ski flying can get you into some of the most exotic places in the world, It is very rewarding.

[aktango58]

Ski flying can get you into some of the most exotic places in the world, It is very rewarding.

for longer than desired/anticipated at times...

[haphogan]

you got that right

[haphogan]

thanks for the link

[Dave Calkins]

Got it Dale. Thanks. D

[schnell49]

V-threads are stronger than ice screws FYI and easy to make--one could take 3 ice screws in the plane and then if needed make as many v-threads as you want (as long as you got some cord to make them and a "coat hangar" type tool--or in case your buddy forgot his tie downs.....) just another idea that doesn't require really any money, bulk, weight etc....and length of screw I believe into straight ice of a lake really isn't going to matter--all the screws from black diamond have the same number of threads on them and thats where the friction occurs--so a 13cm or 22cm screw in solid ice is really the same i.e the longer unthreaded shaft is gaining you nothing...
if conditions are crappy then that's where the length comes in (so you can get deeper in the crap in hopes of solid placement)

remember when setting ice screws to "chip" away at the top surface a few inches to get rid of the crappy ice so you get a solid placement

after placing and if you plan on using them for any amount of time ensure you cover/pack with snow on top so the conduction doesn't rot the ice away from the top down because it will

(screws are what i use....FWIW)

here's an example of a v-thread
http://neice.com/2009/09/how-to-make-a-v-tread/

and if you want to geek out;
http://www.jjgeng.com/html/body_ice_screw.html

Cheers

[Dave Calkins]

....love the second link B. D

[AKClimber]

Here is a simple v-thread made from a coat hangar that I've used for years:
http://cascadeclimbers.com/ice/gear/ice-vthread
Works *almost* as good as the BD one - it helps having the stiffness to push the cord into the hole.
Make sure to get the long ice screws - 22cm and use 7mm cord.
Use double fishermen's knot to tie the cord off after threading through the hole.
One little tip that helps is that it is easier to line up the second hole to meet the end of the first one (deep inside the ice) if you make it from the dominant eye side.
The anchor is only as strong as the ice - clear any cracked, soft, aerated ice out of the way first.
Also cover the anchor with snow/ice shavings to make it last longer especially if it gets sunny.

[dalec]

Here is a simple v-thread made from a coat hangar that I've used for years:
http://cascadeclimbers.com/ice/gear/ice-vthread
Works *almost* as good as the BD one - it helps having the stiffness to push the cord into the hole.
Make sure to get the long ice screws - 22cm and use 7mm cord.

Use double fishermen's knot to tie the cord off after threading through the hole.

One little tip that helps is that it is easier to line up the second hole to meet the end of the first one (deep inside the ice) if you make it from the dominant eye side.
The anchor is only as strong as the ice - clear any cracked, soft, aerated ice out of the way first.
Also cover the anchor with snow/ice shavings to make it last longer especially if it gets sunny.

I just carry 6' of 1" webbing, it doesn't weigh anything, takes up almost no space, thread it through the hole, tie it off, then tie my tiedown rope to it, it is a lot cheaper than cutting rope.

The other thing I have for insurance is a static line along with a couple of pulleys, haven't had to use them yet but suspect it might come in handy dealing with a plane stuck in the overflow

[AKClimber]

I've never tried threading 1" webbing through a v-thread hole, but imagine it would be a bit harder than the 7mm cord.
The stiff v-thread hooker would be the key here.
+1 on the z-pulley setup, and here is where the 7mm cord works better for making autoblocking knots (prussics) than the webbing. I also found that when there is any significant weight 3:1 just won't cut it, so at least 3 pulleys are necessary for 5:1 ot 6:1.

[narrow deck]

Hey Dave,

Nellie Juan spring skiing! I would love to join you and Jerry if you going this spring.
I have 160 Cub with 2500 hydraulics.
I'll call Jerry.
I would like to post some of my ski pics if I knew how to do it on this site. Still learning.
Thanks

[Dave Calkins]

Hi Mike. This weekend weather looks nice.

..not commital yet, though, as I may be taking delivery of a set of wings for my 180.. not sure if it will happen, or what day.....

Get ahold of Jerry. He and others are surely looking at the zones!

[courierguy]

I had planned to add to my usual ski flying equpment this winter a end less rope type comalong http://torcarr.com/index.php?main_pa...gdsm3olsvp2gi8 but never got around to it yet due to the lousy snow year. I can use this year round for general pulling, and it might come in handy when I end up in the quakies again (or how I learned about cross wind up hill landings). The dent in my spinner is always a conversation starter, especially when I point out the prop was undamaged. The best thing about having no brakes, is when you do again come spring, you'll never take them for granted again!