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ski bottom runners

750XL

Registered User
canada
Hi guys, in the process of replacing the bottoms of my Federal 2000's and wonder if I should stick with reinstaling the 3 aluminium runners underneath or if there is a better combo? 1runner in the middle or just on the edges?
 
In my experience with skis I have found that steel works better for runners as aluminum tends to drag more. We have a packed snow over gravel approach to our hanger and when a few stones poke through the snow the aluminum runners stop the airplane dead in its tracks while the steel is a bit more forgiving. It will also hold up better in the long run (not counting rust!). I haven't managed to get up on skis in about 5 years now, the Wx in southern Ontario just doesn't like to cooperate anymore.
 
I don't use any of the original steel runners on my Federal skis. What I have done is close up the screw holes w/ your favorite kind of pooky, and then use new 3/16 UHMW on the bottom. A neat trick that I have done is run the sides of the new plastic about 1/2" past the ski edge and the the UHMW "broke" so it has a rolled edge, as not to get caught if/when sliding sideways.
Attach the new plastic bottom on w/ countersunk machines screws around the edges in a nice pattern.
Use a bolt head as a skeg for directional control. The steel runner don't offer much directional control in the first place...such as on glare-ice.
Anyway, on the inside edge of each ski, directly below the axle, use a bolt instead of a counter-sunk machine screw. You might need to shim the bolthead down some, washers, so it can have some contact w/ the ice....because Federal skis have a convex bottom, which means the sides are nearly 3/8" "higher" than the ski bottom. This type of skeg works VERY well, however it is sacrifical and will need to be replaced every so often.

Good Flying...>Byron
 
Thanks for the tips. My bottoms are riveted on. I plan on doing the same with quarter inch UHMW. Could I go wider out the sides than a half inch or would that be pushing it?

Thanks
 
If you're using Federal 2,000 skis and they don't seem to be enough floatation for you in deep powder conditions, by all means you can extend the UHMW out to the sides to add more floatation.
Taking into consideration you'll be using the heavier UHMW in the 1/4" thickness I see no reason to not go at least 2"+, about 1"+ out each side. Frankly, 1/2" isn't going to do much....more trouble than its' worth. There are 2 main troubles you'll run into. First you'll want to have the outside edges rolled up so they don't catch on something. Second, that ski has a convex bottom, plus its' "banana" shaped front-to-back. Most likey you'll need to make a couple of relief cuts near the middle to reduce the rippling effect on the plastic.
I checked my skis after the first post. The data tag indicates they are Federal 2,500's, and the aluminum bottom is about 12"+ in width. The width of my UHMW bottoms is about 15" (maybe 14 7/8"). I used 3/16" thickeness and had some apperance problems with the plastic because they have some ripples near the middle because of the banana shape of the ski, however they sure work good for what I'm doing with them!

good flying..>Byron

PS..>Don't forget to get the original holes that were used for the metal runners sealed up good! When parking in overflow water can get inside the ski tower and then freeze. At minimum the skis will gain weight, and worst case it'll expland so much as to break the towers from the inside. The only trouble I've ever had w/ Federal skis is keeping the water out of them. I use a good quality marine sealant and ever year run a new bead around the base seems of the tunnels.
.
 
DON'T seal up the center skeg holes, fer cryin out loud!!

Here's a better idea: Remove the steel or aluminum center skeg, and cut (with a table saw) an equal width piece of 1/4 inch UHMW, drill it, and install it as a center skeg.

Get on nasty stuff with no center skeg at all, and you may develop some side drift. Hit something going that way, and you may hook an edge.

There's a good reason skis have a center skeg. Metal skegs aren't that great, cause they tend to frost up really fast, and stick tight. Making a skeg out of UHMW fixes that problem completely and allows you to steer well, as well.

MTV
 
Skis, and associated information...

Mike Vivion,
YOU ARE A GENIUS... Can you tell us where to find the Hooks used for the federal ski rigging?
 
Champdriver,

Hardly.

What "hooks" are you referring to?

Atlee Dodge is the single best source for ski rigging parts, or Landes. But, I don't recall any hooks on rigging that I've seen.

MTV
 
I would guess he means the coiled bungee hooks that are retained by a stout wire clip...
 
Hey....one of my Cubs is N1243A :D

I'll bet they were made about the same time! (1954..?)

We could both fly-in somewhere together and call out: four-three-alpha

__
Mike, point well taken on the runners -however I don't think they're applicable on the Federal Skis.

Kindly keep in mind that Federal skis have the convex bottom. When on surface-crusted snow they turn great, excellent directional control. On crusted snow, with deep powder sugar snow underneath they also do very well. When on glare ice any ski is helped w/ an ice skeg such as a bolt head. The bolt-head skeg has no affect when on snow.

I do agree that runners have a place on flat skis such as Landes, Aero, or Atlee's. Aero 3,000's are a great ski for deep powder conditons.

I'll go so far as to say that I've never seen ANY ski turn as well and have such great direction control as the Federal brand boards. No doubt part of the ease of turning is also because they're so short, most data tags indicating them as 2,000 or 2,500's will only be about 83-86" long. Plus they're banana shaped front-to-back, allowing them to ONLY "sink in" as far as nessesary to hold up the weight under various snow conditions.

For several years I have toyed with the idea of making a "NEW" set of skis. Incorperating some of my own idea's. I should get off my azz and start the process.....the STC part takes a LOT of capital$.

Good Flying..>Byron
 
Byron,

I am in agreement with you on the convex shape, but that's sometimes hard to maintain when you put new UHMW on the bottoms, particularly if you don't stick the skeg in the middle.

The best deal on those convex skis is two skegs, one on each side of the tunnel.

Rocker works well in some snow conditions, no doubt.

Anyway, a plastic skeg will help your steering in many conditions, and it'll not stick down, so I don't see any real down side to it.

Design away. I'm using a set of German retractable wheel skis. Flatter than all get out, but boy do they perform. Everything I ever "deduced" about skis really got hosed by these skis. They are big, and boy do they float.

MTV
 
Luke_theDrifter said:
Hey....one of my Cubs is N1243A :D

I'll bet they were made about the same time! (1954..?)

We could both fly-in somewhere together and call out: four-three-alpha

Byron,

Funny you should bring this up only my plane isn't a cub. My airplane is a C-170B made in '53. My Brother has a '53 C-180 with the last three letters also being "43A". When calling each each air to air we always say "43A calling 43A"......... Let's get together and have a real mix up!!

Bruce
 
Me to....tell us more about these German skis.

Got any picutres? Performance reports? General "likes" and dis-likes"?

thanks..>Byron
 
Anyone know about the Novak brake set up for skis? Supposed to be a hydraulic cylinder on each ski that drives a pin into the ice when you step on the brakes. Anyone have them or first hand information? Crash
 
Them's the ones. Thomas is indeed the owner of the TC. Unfortunately, they are at present only approved in Europe on the model A-1 Husky. Thomas is working on a German STC for the Cub I understand.

The skis are great. Total additional weight is 76 pounds and they float better than straight skis. They also require the use of 8.50 X 6.00 tires.

We got them field approved before the big shut down on field approvals, so don't know if you could do it again.

I can ask Thomas how he's doing on the Cub STC.

MTV
 
Ground Loop,

They ran this airplane against two similar airplanes (same make and model), of similar weight and two other makes and models of aircraft, all in untracked snow. The other airplanes were all on straight skis, all Aero 3000's, I believe, though there may have been a pair of Landes 2500 there.

This setup finished second in the overall takeoff performance in untracked, deep snow. The only airplane that beat it had a long prop (my airplane didn't get the MT prop till a month or so later), compared to the stock prop on this airplane, and it only beat this airplane by about 25 feet. By all accounts, every other airplane was well behind these two.

Any retractable wheel ski that will perform comparably to a straight ski is a good deal in my book.

MTV
 
Your local plastic supplier to save the shipping! Don't know where you are so can't help.

I buy mine from P&A Plastics in Hamilton Ontario.
 
Well Tim, for your sake, hopefully not this winter. I'm headed back to the ME for round two here shortly. Looking forward to the following seasons though as long as the back of the boat spares me again. I want to spend some time flying up in ya'lls neck of the woods for sure.

My current schedule favors New Holstein again. Maybe I'll wear my drysuit this time so I don't get yelled at for crossing lake MI.
 
Be careful over there, I'll look forward to seeing you next summer, and give em hell :evil:

Tim
 
I've thought about this topic for a long time. I like runners or skegs on my skis and I use metal. In soft or loosely packed snow I haven't noticed the runners although I'm sure they help with directional control. In no conditions have I ever had an issue with the runners freezing down. I've had plenty of ice stuck to the UHMW itself, and sometimes I can power it off while other times I have to scrape, but the runners themselves have never been the primary problem. Go land on slick, hard ice? I want metal runners for sure. In fact my Novak ski brakes use a U channel runner that provides two cutting edges that run parallel with the ski length. Those edges are a plane saver on slick ice. I can recall one landing event where there is no question that I'd have wrecked my Cessna had I used UHMW runners instead of metal. That one instance was far more important than any minor inconvenience a little frost on narrow little runners can cause me. In fact that one landing was the reason I added Novak brakes. My cabin requires a tail-up skidding turn around a creek bend on the take-off run so on a normal basis I'm subjecting the runners to shear stress. Again, metal is preferred. That also leads me to not extend the UHMW past the ski edges. My edges have come in handy. Especially when skidding to a stop sideways.

SB
 
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