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pelican-12
11-23-2012, 07:34 PM
hello everyone !!


my question is is it better to have 12" or 15 " wide
my skis are aero 2000 fit on a pa-12 115 hp

in my mind wider will go on top of the snow but it will need more horses powers because we push more snow
what is the answer :roll:

i will put uhmw bottoms 3/16 thick :-?

72A
11-23-2012, 07:45 PM
More Ski the better go with the 15", if you sink down in it will take more power to move.

mvivion
11-23-2012, 09:52 PM
Wider is almost always better, and unless you'll be on really hard, packed snow, the PA 12 is going to want bigger skis.

MTV

cubdriver2
11-24-2012, 12:40 AM
Wider is almost always better, and unless you'll be on really hard, packed snow, the PA 12 is going to want bigger skis.

MTV

Wider skis are great if you have the hp to get them to pack down wet packy snow in front of the ski. It' s just like a wheel chock if you don't have the power to overcome it. I had a little Lyc ( 55 hp) Vagabond that was happy on 6" 1500 Fed skis and would not move an inch on 8" 1500As. You 0320 guys won't understand. A lite 12/115 is a great performer. I would rather have a lite 115 hp 12 then a 200lb heavier 0320 12.

Glenn

16-bravo
11-24-2012, 02:26 AM
I have experience with both wide and narrow skis. It all depends on the snow conditions. I think that the wide ski is best suited for spring time snow, that gets soft in the afternoon from the sun. I have been running Landis 2500's for about 2 years now, and I would say that they out perform the wider ski in the deep deep snow. The wide ski tends to plow in the deep, and if you dont have the horsepower, your going to be going around for another try (Ive done it). The shorter wider ski is better for ground handling for sure, but I believe that the longer narrower ski comes out of the snow quicker. BTW, my Atlee board skis are 19 inches wide, and my 2500's are about 14 inches. Ron

aktango58
11-24-2012, 03:08 AM
How much snow are you talking about?

If you are only in 6", it might not matter. If you are landing around here, it is not uncommon to find three feet of soft snow, and the ski is an issue. I had my first cub laying on the belly in deep snow one time, I wished I had bigger skis that day.

nanook
11-24-2012, 09:03 AM
I seem to remember that part of the ski certification/approval process involved; what width ski the aircraft could handle in flight with "the broken front cable/ tip of the ski pointing down in flight scenario"... Too wide of a ski at some point represents too much drag to overcome in flight. In other words "a loss of control in flight"... Not a pretty picture to consider landing an aircraft that won't stay in the air on a ski pointing down....

mvivion
11-24-2012, 09:22 AM
I have experience with both wide and narrow skis. It all depends on the snow conditions. I think that the wide ski is best suited for spring time snow, that gets soft in the afternoon from the sun. I have been running Landis 2500's for about 2 years now, and I would say that they out perform the wider ski in the deep deep snow. The wide ski tends to plow in the deep, and if you dont have the horsepower, your going to be going around for another try (Ive done it). The shorter wider ski is better for ground handling for sure, but I believe that the longer narrower ski comes out of the snow quicker. BTW, my Atlee board skis are 19 inches wide, and my 2500's are about 14 inches. Ron

i dont necessarily disagree with this point, but i thought what he ASKED was what width bottoms to put on a particular ski, not what SKI to choose. Total bottom area is more important than width in DEEP snow, and one of the reasons the Landes skis are such great skis is because they are very large skis, when it comes to total bottom area.

if he's working with just adding plastic, he may be able to get them a bit wider, but longer isn't going to happen, and in DEEP snow, those little 2000s are going to be pretty small.

But, maybe I misread his question.

MTV

beaver18
11-24-2012, 09:24 AM
Nanook i would not be to shure about that part of the certification prosess , i dont think any aircraft would be able to fly with any of the wheel skis out there with a broken front cable, and regarding how wide you need to find a good balance with the horsepower ,a wide ski is hard to move at 35 mph in wet snow but keep you on top of the snow, there is no perfect anwser ,for support you need more surface the opposite for drag (narrow and long would be perfect if it was alway in strait line).

sierra bravo
11-24-2012, 09:43 AM
Skis are great for ground ops but they aren't great in the air. Wide skis are worse in the air than narrow skis. Wide skis MAY have some advantages in some snow conditions but for the most part a moderate width ski that's longer will be better for all-around ops. If you're a typical ski flyer who operates from groomed strip to groomed strip it makes better sense to use narrower skis and not suffer the drag from wide skis in the air. Like all mods, the "best" answer is subjective and depends on your intended use. Very few guys use skis in the extreme conditions they refer to in ski discussions.

skywagon8a
11-24-2012, 04:18 PM
Skis are an interesting topic. Deep fluffy, deep crusty, thin crusty, thin fluffy, heavy plane, light plane, small horsepower, high horsepower, etc., etc. It is enough to tear your hair out trying to decide what configuration to make your ski. Has anyone ever made a wide ski with a narrow ski below it in order to utilize the advantages of both types? Would this work? or not?

I am toying with the idea of making my own wheel penetration skis out of wood to fit over the 26" Goodyear tires. These clearly would be quite wide. Perhaps a narrow strip under the center would help lift out of deeper snow? Maybe I am all wet and this is a dumb idea?

beaver18
11-25-2012, 09:57 AM
skywagon8a, i think Trickair would probably fit your need without to much problem because they fit 8.50x6 with 24 in dia and there is room for a bigger tire and they go pretty good in snow.

skywagon8a
11-25-2012, 10:42 AM
beaver18, That is a thought. My plan is to make my own simply because I need a project. After 12 years of retirement my bucket list is getting very small.

mvivion
11-25-2012, 10:56 AM
skywagon8a, i think Trickair would probably fit your need without to much problem because they fit 8.50x6 with 24 in dia and there is room for a bigger tire and they go pretty good in snow.

the important difference in this case is the WIDTH of the Goodyear 26 in tires, not the diameter. I've experimented with these ties with two different models of wheel skis, and the slight width difference of these tires precluded their use. Try em before you buy em.

MTV

mvivion
11-25-2012, 11:04 AM
Skis are great for ground ops but they aren't great in the air. Wide skis are worse in the air than narrow skis. Wide skis MAY have some advantages in some snow conditions but for the most part a moderate width ski that's longer will be better for all-around ops. If you're a typical ski flyer who operates from groomed strip to groomed strip it makes better sense to use narrower skis and not suffer the drag from wide skis in the air. Like all mods, the "best" answer is subjective and depends on your intended use. Very few guys use skis in the extreme conditions they refer to in ski discussions.

Skis and their rigging are MASSIVELY draggy. I seriously doubt a slightly wider ski is going to significantly increase drag on one of these planes.

Ive run Aero 3000 skis on a number of different models of airplane, and, while they are very wide compared to other popular skis, I've found them to be great skis in a variety of conditions.

there is no doubt that wide skis work better in some conditions, while narrow work better in others. But again, total bottom area is always pretty important in deep snow.

too many different snow conditions to suggest that any one design is best for all.

MTV

skywagon8a
11-25-2012, 11:07 AM
Mike is there a big disadvantage to making a wide ski that would go around the outside of the 26" Goodyears? Such as being just too wide to be practical? My current thinking is that I would need to attach the ski to the axle area both inside and outside of the wheel for structural stability.

aktango58
11-25-2012, 11:11 AM
While total bottom is a big factor, we have found that long narrow boats will get up on step with less hp than the wide short boats. Talk to marine architects and they will explain that length of boats will make a big difference in the turbulance of the water...

another advantage of longer skis is that the will bridge over more bumps and offer a smoother ride in washboard.

But that said, if you have skis that work, no reason to get to deep into the 'should I get better'. If I were going to improve, it would be with wheel skis to make life easier.

I have seen AWB's on a PA-14 with Goodyears. Took a bit of sheet metal work to make them fit the guy said.

Dave Calkins
11-25-2012, 01:05 PM
Skis are great for ground ops but they aren't great in the air.

From PA-11's to Cessna 185's I have found my fastest gear configuration is straight skis. Airglas vs. Aero doesn't seem to matter. (narrow vs. wide, respectively doesn't matter).

(a short-term installation of 8.00 x 6 tires were the fastest on a 185. They were only on there for a few flights to rig and test a rebuild, but what a hoot to go that fast......for an Alaskan boy accustomed to 20 MPH slower cruise with the normally installed Tundra tires on that fine airplane.)

Floats on Cubs the second fastest configuration. (on 180/185, Bushwheels and GarAero's second fastest)

Bushwheels on Cub the third. (180/185, floats third fastest)

Wheelskis the slowest configuration for Cubs and 185's, in my experience.

...I suppose your mileage may differ.

beaver18
11-25-2012, 05:54 PM
Dave i have to agree with you on this one , i flew my cub in 3 different ski configuration, the fastest is straight ski, second Trickair (- 3 mph ) and the slowest one and heaviest Fli-lite 3000 (- 12 mph ), and but i would not go back to straight for ease of use and versatility.

energytech
11-25-2012, 07:22 PM
I had this experience in the mid 80s when we had several high snow years in the interior. Flying a PA-20/150 with a 82x41 borer prop I landed at our homestead in the Kuskokwim mountains on a beautiful February day. I stopped in a quick mush with snow rubbing the belly only to find the door was a foot below the snow surface, probably six feet of deep snow there. After struggling to just get out of the plane and shovel my way out from under the wing I packed an area flat so that I could put my snowshoes on. I'll never forget the work it took to stomp out a trail in front of me so I could take off. Sweating profusely at -20F requires special care to stay dry.

It took a major effort to shovel and hard-pack a steep ramp out in front for the plane to ride up and onto the softer runway ... a real pain as I didn't have time to spend the night and let the whole thing set up and get hard. We have what many call corn snow in the interior and it doesn't pack well in any kind of rapid manner. Letting it set over night or even five or six hours will allow some structure to form and better support weight on the surface. Luckily I had Aero 3000 skiis which are considerably wider than the 2000s. The width is important here as a wider ski rides up and over a weak snow ramp instead of plowing or cutting through it in a situation like I was in. Of course it makes little difference which ski you fly if there is very little snow. Thankfully I only had two or three other experiences like this one. Two times were in a PA-14 and on rivers where the snow drifts in to make similar deep powder situations. Another was in the Alaska Range on the side of a mountain where I had no business being.

You may consider speed in the air and equip yourself for that phase but getting into the air is more important to me. Got snow? Go wide!

nanook
11-25-2012, 07:52 PM
I know that some people are stuck with them...but wheel skiis suck big time in any kind of deep snow. The interior is straight ski country. Dry snow is a pain when it gets deep. Some up here prefer the longer narrower landes/airglass ski. Some prefer the Federal/aero type wider ski. I like the wider single center skag federal type ski. I think the airglass is over-skagged and too flat. Whatever works for you....you are still held to the rule of only 10% over the certificated size if you are trying to get it approved.

nanook
11-25-2012, 08:01 PM
Beaver18 there have been many instances of broken cables with a ski sticking up or down. They will fly, the worst is the tip down obviously. An 800 helio landed in SCC with one sticking down....

Torch
11-25-2012, 10:07 PM
When I bought my Atlee Dodge skis I called Atlee himself. Sure do miss him. It was great when you called and he answered the phone. He asked me if they were his 12 or 14 inch skis. I told him they were the 14's. He said they were worth about twice what his 12's were and I should buy them because the 14's were better. I got the 14's for $400 used. Money well spent.

mvivion
11-25-2012, 10:33 PM
And, that's the point: Different snow conditions in different parts of the world will favor one ski shape over another. There is no perfect ski, but I agreed (note the past tense) with Nanook regarding the terrible performance of wheel skis UNTIL I started flying the Rosti Fernandez wheel skis. Those will outperform most straight skis, and at 76 pounds total additional weight, they don't hurt your useful load as much as others. Otherwise, wheel skis are a serious compromise.

Pete,

The question I'd ask is this: Where do you plan to operate where you'll need BOTH big tires and skis? For years, we ran modified Fluidyne 2200s with long rigger arms and installed them with the old Goodyear 25 inch Airwheels (not to be confused with Bushwheels). REALLY heavy, and, unless you were landing on ocean beaches AND occasionally snow, pretty useless in my opinion. The one I flew mostly where there wasn't much good snow in any case.

I think you could design a ski to fit around the Goodyear 26 tires. Question is: Why? There may be a mission out there, what's yours?

MTV

mike mcs repair
11-25-2012, 10:35 PM
Beaver18 there have been many instances of broken cables with a ski sticking up or down. They will fly, the worst is the tip down obviously. An 800 helio landed in SCC with one sticking down....

back in Late 80's, big tall Allen Tibbets in Naknek broke the front cable on his Tcraft, so he gets his LONG leg out the door, stalls it, tips ski back up with his leg, then has to stay like that till he landed....

T.J.
11-26-2012, 01:24 AM
Nanook.
Where is the "rule" for 10% over certified size to get approival?
thanks.

sierra bravo
11-26-2012, 06:18 AM
I know that some people are stuck with them...but wheel skiis suck big time in any kind of deep snow.

On a Cub? FliLite 3000s work very well in the snow. Surprisingly well. I suspect Scooter will enjoy them a lot on my old PA-12. Especially when dealing with maneuvering in and out of a hangar. On my Cessna I'm still pleased with my Fluidynes. They work well for my needs but I don't plan on landing in remote places where they just had 5 day snow storms with tons on new snow. I don't need to. I'm not at all afraid to land in average unpacked snow after a few passes to lay a track. Simple stuff. Not unlike what I used to do on straight skis. It must have been 12 years or more that I've had hydraulic skis. I've never had any desire to install my straights since.

skywagon8a
11-26-2012, 07:50 AM
Pete,

The question I'd ask is this: Where do you plan to operate where you'll need BOTH big tires and skis? For years, we ran modified Fluidyne 2200s with long rigger arms and installed them with the old Goodyear 25 inch Airwheels (not to be confused with Bushwheels). REALLY heavy, and, unless you were landing on ocean beaches AND occasionally snow, pretty useless in my opinion. The one I flew mostly where there wasn't much good snow in any case.

I think you could design a ski to fit around the Goodyear 26 tires. Question is: Why? There may be a mission out there, what's yours?

MTV
Mike,
Around here we don't get much snow anymore. If the past several winters are any clue to the future, I will not have any use for skis at all. Last winter there was a skim coat of ice on the lake for only one week. In the past it has been a foot thick for most of the winter. In fact, the 26" Goodyears are likely overkill, though the extra diameter is attractive. There are not that many places where we can land without getting in trouble, or at least stirring up a commotion, that a set of 8:50-6s won't do the trick. To answer: Why? The idea is to simplify the process with just one set of tires and a set of skis that can be just slipped on for the rare occasional use. I also believe that skis might be a safety factor when transitioning across thinner ice near the shore to the parking spot on land.

We don't need to address thin ice out in the middle under thin snow, been there, done that, don't need to do that again.

Is there an equation for the number of square inches of ski area for the gross weight of the airplane? How many pounds per square inch?

N5126H
11-26-2012, 02:20 PM
"The question I'd ask is this: Where do you plan to operate where you'll need BOTH big tires and skis?"

Some of the best flying in South Central Alaska is in the spring on wheel skis with large tires. I had 26" and AWB2500. I could land on the sand bars of Polly Creek and go clam digging in April, Land on spots up the Knik and the Su, land on the snow fields in the mountians and sun bath and return to the paved runway of Anchorage.

AWB with 26" tires allow you to operate on sand bars without damage to the skis. If you live in Western Alaska and want to beach comb after the big spring storms AWB with 26" tires are the way to go.

Bill

sierra bravo
11-26-2012, 03:09 PM
Ditto for Fluidynes with long arms and 850s. Ground clearance is nice to have even for pushing the plane around in the tie down. But that's hydraulic skis. I took the earlier question to be aimed at putting 26s on fixed penetration skis. That makes no sense to me but maybe I misinterpreted the post.

mvivion
11-26-2012, 04:01 PM
Bill,

I know, I've been there, and as noted in my earlier post, operated a Cub on C-2200s and Goodyear Airwheels. But, he doesn't live in that part of the world, which is why I asked the question.

Even with that, I'm not sure you'd get extended arms approved on a set of skis these days. Maybe still in AK. He's experimental, so that wouldn't matter.

Pete,

Understood. I'm vacillating between going to bigger tires on my 170, which I would use a little, but.......not a whole lot. The problem is, my wheel skis would no longer fit with those tires on, and that would mean two sets of tires and a bigger deal switching from wheels to skis and back. Unless of course, I want to buy another set of wheels and brakes, etc, etc...... Last winter, I left the skis in the hangar.. Noplace around here close where ski flying is very practical, so for the first winter in thirty years, I went a winter with no ski flying.

MTV

Henny
12-02-2012, 02:51 AM
Beaver18 there have been many instances of broken cables with a ski sticking up or down. They will fly, the worst is the tip down obviously. An 800 helio landed in SCC with one sticking down....


back in Late 80's, big tall Allen Tibbets in Naknek broke the front cable on his Tcraft, so he gets his LONG leg out the door, stalls it, tips ski back up with his leg, then has to stay like that till he landed....

This is from a 2010 FAA Alaska Local Area Knowledge video. Interesting advice on how to handle a broken front check cable. Any thoughts?


http://www.youtube.com/watch?v=TrdYTDO31r0

beaver18
12-02-2012, 08:00 AM
Pretty good vid Henny could be usefull if it would happend ,that made me think of those angle top end of the pedestal in my Trickair they are an extra safety feature they will hit the welded fitting on the gears and prevent too much angle on the skis in the event of a broken cable ( front or rear ).

nanook
12-02-2012, 08:38 AM
TJ the 43-13-2A listed the 10% rule for oversized ski installations. -2B now names the oversize limitation but doesn't give it to you? Might be a typo in the new AC-43-13-2B

sierra bravo
12-02-2012, 12:50 PM
Since the limitation in 43.13-2B isn't defined wouldn't it be the mechanic's responsibility to determine acceptable limits? It looks to me like that's the intention of the language. Adding wider UHMW to the bottom isn't a structural mod and shouldn't change the load rating of the ski.

skywagon8a
12-02-2012, 02:33 PM
AC-43-13-2B is only addressing the installation of the skis on the plane. TSO-C28 is supposed to cover the design of the skis. Does anyone have a good link to the TSO. I've been unable to find it. The FAA.gov site doesn't seem to be able to come up with it. I am particularly interested in learning if there is an "official" rule for the number of square inches required for a given aircraft weight.

nanook
12-02-2012, 03:14 PM
-2B is incomplete. It names the limitation but then fails to define it. -2A was defined as 10% of the approved size/shape. This is in relation to the flight characteristics. Maint. Can determine structural and travel/movement but not flight. This is the oversize ski limitation, AC43-13-2B chap.5, 503 d

ysifly2
01-01-2013, 08:05 PM
Looking for any suggestions from any experienced ski plane flyers...

I am having a little difficulty determining how best to rig the skis on my Pacer. PA22/20 to be exact, and with a two - three inch fairing that is on the back of the rear landing gear tube. Because of this I am not able to use the rear gear-to-fuse fitting for the rear ski cable, as the angle from the bolt attach to the rear of the ski cuts right across this fairing.

Going to try an attach a picture that shows a better than I can explain... Pictures worth and all
9748

Thanks,
Bryan

aktango58
01-01-2013, 08:16 PM
Take off the fairing.

Or, take the rear check cables to a set of aft float fittings...

mvivion
01-01-2013, 08:22 PM
George is right.

ive never liked the angle of the rear cables to the aft gear fitting. I'd find a set of clmp on float fittings. Better angle. And front cables attach to lower engine mounts.

again better angle of cables.

But, you may be able to simply notch that fairing to make it work.

MTV

aktango58
01-01-2013, 08:56 PM
I happen to now have a set of bolt on float fittings that are redundant.

Weld on fittings on the new cub, so the bolt ons can go away.

ysifly2
01-01-2013, 09:19 PM
The fairing doesn't easily remove, as it is covered by the gear leg covering. If we were sure to get significant snow that would ensure plenty of ski flying, may consider, but trying to do without that. Cutting the fairing (or trimming) could be another option... Would likely require modifying (or creating new) gear to fuse fairing covers. ( attaching a couple other pics of the plane to get a bigger picture of the area.)
9750. 9751

With the clamp on ski fittings... Presume would have to cut a clearance of some sort thought the covering to gain access to the lower longeron... Yes?
Attaching the front cable and bungees to the engine mount would require cutting a hole of some sort thought the lower cowl, as it wraps down under the fuselage enough to not have a straight shot to the mount bolt.

I had thought about making a tab, the next size longer bolt and using the rear strut fitting... Thoughts?

Thanks!
Bryan

aktango58
01-01-2013, 10:00 PM
The tab WILL pull towards the ski tail, and it will move a bit, so you want clearance.


The bolt on float fittings go on the cluster behind the gear, and you do poke holes for the u bolts. The can cause some issues with the longeron from the u bolt that have to be tight.

cubdriver2
01-01-2013, 10:55 PM
Longer bolt and a bushing to move the tab back past the fairing?

Glenn

mvivion
01-02-2013, 09:08 AM
To attach to the engine mount just requires cutting out a small square of metal from the cowl and installing a tab. Easy and clean, and the tab stays there, skis or no.

MTV

nanook
01-02-2013, 10:05 AM
Actually it requires an 1/8" longer mount bolt be installed. Use the good heavy duty Atlee Dodge type tabs. Get the tab angle set correctly (before you cut the cowling) and an A&P/IA to sign off on your modification....