Plans for skis

[LSaupe 123]

Has any of you actually tried the Acrolite 1300's before (or know someone who has)?  I just ordered a set of plans.  Getting in and out of the hangar with ski's only will then be the next challenge.  We will see how complicated they look once they come in.  Sure do like how the Mangy is set up though.  Slip on roll-through.  Cant get much better than that.

http://www.acrolite.org/acroskiis.htm

 

[1avidflyer 1983]

Here is a picture of the skis I've made for the Avids and such.  I've made 5 or 6 sets of them.   Some sets went with planes when I sold them, and sold a few sets as well.   They work good, but they aren't wheel penetration skis however.  I started making a sketch for them, but it's not totally complete with all dimentions.  Maybe I have it on this computer.  I'll look.   JImChuk

[LSaupe 123]

Those sure look similar.

[EDMO 1078]

Some input from a non-snow-flyer:  I see so many advantages in the open-sided wheel skis that the other skis don't have, that I believe I would be investing in that type if I needed skis.   The only advantage of the regular non-wheel skis that I see is that you can get rid of the weight of the wheels, tires and brakes in the winter, just about the time your plane starts to perform better in the cold air and you need more survival gear.  Just some thoughts gathered from your photos and posts.  The snow-fliers have to decide which is best for them.  

BTW:  I was told by a Crew Chief in the Alaska Air National Guard that the C-130 can make one landing on concrete with the Teflon skis and the liners then have to be replaced.   Merry Snow to those who like it.    EDMO

Edited 25 Dec 2016 by EDMO

[LSaupe 123]

Jim:

What does the underside of your ski look like?  Any skegs?  Any issues with making turns on snow (or problems with excessive turning moment on the gear)?

Any chance to see the rest of your dolly system?  Trying to figure out a good way to get in and out of the hangar.

 

[1avidflyer 1983]

Here is what the bottom of the skis look like and also the cart.  Without the extra piece on the bottom of the skis, it wanted to slide sideways more than turn, especially if it was packed snow or icy.  The piece is more plastic, that happens to be black instead of white.  Pushing forward on the stick and adding throttle helps to turn the plane, especially if you are going slow.  On the cart,  The front ramps hinge on the back pipe, and pivot to flat as the wheels or skis go up them.  For the tail wheel, the aluminum piece laying on the ground past the cart is a  ramp that pins into the back of the cart, and allows the tail wheel or ski to side or roll up onto the back of the cart.  Then it pops off to move the cart.  The winch helps out by pulling the plane up the ramps.  JImChuk

[LSaupe 123]

Love it.  Thanks for posting.

[Bandit 286]

The Avid gear is real flimsy when on skis. When taxing over rough snow the skis are twisting and turning. Do not turn the airplane when pushing it in and out of the hanger unless you are moving it forward or backwards. Especially in deep snow. 

[1avidflyer 1983]

I wouldn't go so far as to say flimsy, ever try to adjust the toe in with an 8' long pipe on the axel?  :-)  That takes a lot of pressure, in fact, it was all I could do holding onto a rope that was tied to the tailwheel, and the pipe against my belly.  None the less, I do agree with you that the plane should be moving when you try to turn it.  JImChuk

[TJay 1041]

What are you guys using on the bottoms of them, Like a 1/8 plastic or the expensive stuff from spruce,

[Av8r3400 1178]

I used UHMW from a local plastic place, bought a 5x5' piece.  I don't remember the thickness, I thought maybe 1/4"?  

Expensive, yes, but not as much as the stuff from ACS.

[1avidflyer 1983]

I used the white 3/16" thick UHMW.  I did get a sheet of 1/4" black once, and made several sets of skis with that as well.  The 3/16 seemed to be strong enough.  I don't think you would want to go any thinner.   One thing about it though, on my skis, I have a lot more surface area for the plastic to rest up against and be supported by.   Not near as much support with the Avid wheel penetration skis.  Then probably the 1/4" thick would be well advised.   Last time I got some, I bought a 3/16" x  4' x 10' sheet from Sealy Plastics in Duluth, Mn.  The 3/16" stuff could be rolled up into about 2' diameter roll.  I carried it home in the back seat of the car.  I think the last time I priced it out, it was about $100 more than when I bought it.  New price was about 250.  JImChuk

[Av8r3400 1178]

I think I paid `$75 for a 5x5' sheet back in '13-14???

[TJay 1041]

Wow!  That is an OOOOLLLLLDDDD photo.  Probably from the first winter I had that plane.  Those were Avid Skis that I got from Airdale.

These are my "new" skis.

On the wing...

Video evidence:

 

 

(Headed to the airport tomorrow to do my first Mangy annual and rig these skis on it...)

 

right off hand what would you guess he used for size and wall thickness tubing?

[Av8r3400 1178]

These were made with 5/8" x .035" I think for the main frame.  Some of the smaller tube is 1/2". 

[LSaupe 123]

My plans are calling for 3/8" thick UHMW (8" x 60").  Only sources I can find want a very large quantity order.  Anyone know of a good on-line source for this stuff this thick?  Needs to be this thick for structural reasons.  Either 3/8" or... 1/8" aluminum and 1/4" UHMW (though 1/8" aluminum is HEAVY).

[TJay 1041]

My plans are calling for 3/8" thick UHMW (8" x 60").  Only sources I can find want a very large quantity order.  Anyone know of a good on-line source for this stuff this thick?  Needs to be this thick for structural reasons.  Either 3/8" or... 1/8" aluminum and 1/4" UHMW (though 1/8" aluminum is HEAVY).

Did a search and someone said this. The last time I redid my bottoms I used what they call "reprocessed" UHMW. Its black with little specks in it. As I understand, they regrind all the scraps from the manufacture process and recast it. It seems to be a lot more UV stable than the white. The white is food grade plastic and is not UV stable, and as MTV noted it will eventually degrade and crack then its done for. The black reprocessed is about 2/3 the cost of the white food grade in all thicknesses. We have also used blue, which is a lot more abrasive resistant than either white or black, but at twice the cost. If you can buy a whole sheet it saves a lot $$. We use a ton of the stuff in conveyors and truck bodies and get it in 5 x 10 sheets. If you know a contractor who runs trailer dumps most of them are lined with 1/4 Tivar or uhmw, and the bottoms of the trailer are worn out long before the sides. You can get some pieces for cheap if they are not beat to pieces over time. 2 places in Maine sell the stuff and ship it any size, Haines Manufacturing in Presque Isle 207-762-1411, and Lane Supply in Brewer 800-432-7667 both good guys.

[EDMO 1078]

I have an MSC catalog and I know they sell the UHMW and all kinds of alphabet stuff - If you cant search them online I will get my big catalog from the shop and see what I can find for you - Looks like we have one more day before a 3-day ICE storm hits.   Grainger might have it too, but I am not sure about that.  I have their big catalog too.  

I just looked in Grainger catalog and I know the prices have probably gone up - 3/8 x 24 x 48 would not do for what you need - next size is 48 x 96 for $672 White, and $477 Black - Like TJay said, the black is cheaper than the white.   If you could use Polyethylene, it is only $211 Black, $194 White, (note there is a low-density and a high-density).   ABS is only $166 a sheet, and they used to make canoes out of that.    I haven't checked Teflon, but I think it is priced with Gold!   EDMO

Edited 12 Jan 2017 by EDMO

[LSaupe 123]

Dang this stuff is expensive. I will check out those sources. Thanks Guys.  Might be worth the weight penalty to go with the aluminum base and 1/4" or 1/8".

[LSaupe 123]

Ran across this place and it appears pretty reasonable.  Cut to size as well.

https://www.interstateplastics.com/Uhmw-Black-Reprocessed-Sheet-UHMBR~~SH.php?sku=UHMBR++SH&vid=20170112100551-3p&dim2=8&dim3=60&thickness=0.375&qty=2&recalculate.x=91&recalculate.y=17

 

[TJay 1041]

What are the other uses for this type plastic? Milk Jugs, Oil Jugs,

[1avidflyer 1983]

I found that the black UHMW I had was not as slippery as the white stuff.  It did work, but the white was better in my opinion.  If it was me, I would spend the extra money and get the white.  I do think that 3/8" thick is a bit of overkill though.  I used 3/16" on my later sets of skis, and they worked fine.  It seems that Larry's skis are 1/4" and seem to be holding up just fine.  JImChuk

[EDMO 1078]

What are the other uses for this type plastic? Milk Jugs, Oil Jugs,

TJay,  I am no plastics expert - milk jugs are polyethylene, I think - That is what Dean used for bushings on the flaperon hangers originally.  There are probably good sources for plastic info on the internet, but when I need info I go to my Graingers and MSC catalogs to read about them - they usually give hardness numbers, temperature ranges, and sometimes tell what the plastic is used for.   UHMW White is approved for the food industries, and is used a lot for guides or conveyor parts.   You can buy it in several extruded shapes as well as sheets.   EDMO

[akflyer 1427]

I see some pretty skinny ski's here.  If your flying off of pretty well packed snow or snow less than 6" deep they work fine.  I can tell you though, Ski flying becomes no fun when you find some good snow and slow down in it and find yourself sunk up to the belly of the plane.  Wider is better!  yes, the skinny ski's are easier on the axles when you are turning the plane by hand, but I would rather be a little tougher on the axles than spend the night tramping down a runway and digging out an airplane.

There is a pretty good reason why the skinny ski's of yesteryear are not made by the big producers anymore.

 

 

[EDMO 1078]

I see some pretty skinny ski's here.  If your flying off of pretty well packed snow or snow less than 6" deep they work fine.  I can tell you though, Ski flying becomes no fun when you find some good snow and slow down in it and find yourself sunk up to the belly of the plane.  Wider is better!  yes, the skinny ski's are easier on the axles when you are turning the plane by hand, but I would rather be a little tougher on the axles than spend the night tramping down a runway and digging out an airplane.

There is a pretty good reason why the skinny ski's of yesteryear are not made by the big producers anymore.

 

 

Leni,  What is your definition of "skinny" and "Wider is better" in inches and also length, for AvidFoxes?   EDMO