Skis?

[Mark Harwood]

Is there a ski that is easy to use on snow, ice and frozen plowed turf? When I mention getting skis for my 170 to some fella's with time under their belt, they reply that skis are a lot of work. I live on a lake and would love to land on the lake, but would not want to leave my plane on the lake for an extended time.(maybe a few days) I would want to get back to the field for fuel and to hanger. I would need to be able to traverse plowed turf to get back to my hanger and be able to get it back in the hanger. Are skis worth the hassle for the use I am describing?
Would I need to make any modifications such as axles?

[blueldr]

Sounds to me like you need wheel peenetration skis. pretty spendy for non commercial operations and a relatively short season.

[jrenwick]

Mark,

You've opened a very deep can of worms, full of things to learn about, and with potential for an awful lot of fun. I fly my J3 on skis in the winter with a group of similarly-equipped friends. It's a blast when it works out.

TIC170A member Bob Boyd kept his 170 on his lake in Wisconsin last winter, but I don't know if he's there again this year. He uses straight skis. You there, Bob?

I'm not sure what you mean by plowed turf, exactly. If it's OK for wheels, it might be OK for hydraulic wheel skis. (I have a set of Fluidyne Fly-Lite 3000 hydraulic wheel skis that I'd like to sell.) These are skis that you can pump up and down, so you have your choice of landing on wheels or skis each time.

Then there are wheel penetration skis without hydraulics, where the tire pokes through a hole in the skis, but not far enough to mess up operation on snow. These work on hard-surface runways, but might not work on rough fields without snow.

Aero-SKi, in Brooten, MN, makes a retractable ski that lets you convert from skis to wheels once while in flight by pulling on two cables. You have to be on the ground to put the skis down again. There's a story with photo here: http://www.flyingmag.com/article.asp?se ... cle_id=872.

There's a web site, http://www.treetopflyers.org, that might be helpful. It might even help you get in touch with ski flyers in your area. That's what you really want, because this is something best learned by doing it with other, more experienced, ski fliers. (There are plenty of hazards, and lots of tricks to learn.)

I think most skis for 170s require metal brackets that are bolted to the side of the aircraft just behind the firewall and in the area of the rear seat. The bungees, safety cables, and check cables attach to these points. Wipaire, in St. Paul, MN, can sell you these parts if you know what kind of skis you're going to install.

Some skis come with their own axles, others use stock ones. There are steel axles that are recommended for use with skis, because skis can put more strain on the landing gear legs than wheels do. We've had several discussions on axles; here's one: http://cessna170.org/phpBB2/viewtopic.php?t=1361

Happy flying!

[hilltop170]

Mark-
If you can find a set of Federal AWB-2500 hydraulic wheel-skis, they are absolutely THE BEST ski for the 170. They were originally designed for the L-19 and came with all the fittings and brackets required for installation. There are still NOS sets in the original crates out there, I bought a NOS set in 1990 and I know a guy who is still sitting on one.

There are other skis available as jrenwick detailed in the previous post and they might be good but the AWB 2500 in an excellent ski. I flew a set on a Super Cub for many years. The AERO Ski is also a very good ski and I know Maule guys who wouldn't fly anything else. Last I heard they were not approved on Cessnas but that may have changed.

In any case you'll need fuselage fittings installed (Atlee Dodge sells excellent stainless steel Cessna fittings) and will need to fab up the check cables and install the hydraulic pump, fittings, and hoses.

It's a lot of work but well worth it if you live in a place that stays frozen thru the winter.

IMHO, DO NOT get wheel penetration skis, because the wheel protruding below the ski creates so much drag that the 170 just does not have enough power to perform satisfactorily, even with a 180hp engine.

If straight skis are what you decide on, they perform well and are easy to install but are limited to ski flying only. Retractable skis offer the flexibility to land on wheels or skis, your choice. Sometimes you won't know which you'll need until you get there.

[Paul-WI]

I have to agree with Richard about the wheel penetration skis. I have a set of Schneider Skis on 58D and in deep snow, forget about it. If I had to buy a set of skis, I would look at some type of retractable ski. But once you fly with skis, it is a blast. I have not had a chance to get out on skis yet this year as ice conditions have been pretty bad around here as well as bad weather - but hope to get out this weekend.

Good hunting!

Paul

[denalipilot]

I'm entirely pleased with the cost and performance of my AERO 3000 straight skis, although my situation is a lot different from the original post. I tie down outside, winter lasts forever here, and I can refuel at my tie down while on skis, as well as at a lot of the places I fly to on skis.

I'm actually surprised by all the recommendations in favor of hydraulic skis. Sure, in theory they're the best of both worlds. But in reality, even if the price tag wasn't a deal-breaker for me, the extra weight (and induced drag) seems like it would really cut into the performance of our lovely but humble little airplanes. If I was a C 180/185 guy, I would want hydraulic skis. But with the take off roll already lengthened by variable snow conditions, and all the associated weight of winter survival gear, wing & engine covers, portable preheater, etc, my focus is on keeping the plane light enough to still perform. Are you guys all running 180 hp conversions and CS props?

Back to the original question, seems like he wanted a low-commitment chance to see what ski flying is like. Straight skis don't hamper your performance too much, and are far cheaper than hydraulic skis or even wheel penetration skis. UHMW plastic bases will help on the frozen turf, and you can always shovel snow lanes into your hangar to pull the plane in. But beware, even with plastic, sliding on anything other than conducive snow/ice can be a mother.

One other consideration- the hydraulic skis I'm familiar with limit your tire size- usually to 8:00's. For anybody running bigger tires, this would mean keeping a set of winter tires in addition to a set of summer tires.

In any case, I hope you get to try ski flying. It's a blast. I believe the FLYING article referenced above is the one I just read in my dentist's office. If I were looking again, I would give those skis a look, only because I have been so satisfied with AERO in the past. Good luck.

-DP

[Bill Rusk]

The 170 does not really have the Hp to dig itself out of deep powder, and it certainly would be a dog with anything other than straight skis. It is also somewhat rudder limited on skis. It performs adequately on straight skis in mild conditions and is a LOT of fun on skis. You will need solid steel axles. There are several posts on this site referencing axles. The plane will taxi over plowed fields on skis but remember that skis are bolted directly to the gear with absolutely zero shock absorption, and so unless this field has 8" plus of snow, it will be hard on the airframe and may well knock your fillings out. Insurance does not increase on skis, at least not with Avemco. It would be helpful to have a seaplane/low pitched prop also.
Mine is a stock 170B with Federal 2500 skis.
Lots of fun but go in carefully and build your experience up.






Bill

[yukontools]

I sent you a pm looking for more info on the NOS AWB 2500 skiis. Does the still have them?

Thanks.

[Mark Harwood]

Thanks for the replies! I am leaning toward straight skis. Hydraulics are more $ than I want to spend. I like the dolly set up on the federals. I found a pair of federal 3500. Is there an STC for 3500? Are there any significant drawbacks to the 3500's? Bill thanks for the photos. Nice bird! I am curious how the cables attach to the gear leg. I was picturing having to put attachment points on the fuselage. What you have looks much simpler. Can I bother you for a close up of the upper gear leg? Thanks again Mark

[Bill Rusk]

Mark

Sorry I did not respond to your questions.

The Federal 3500 ski is not approved on the TCDS for the 170. As a result you will need to get the FAA to sign off on it. This could be a problem. It is also a much larger ski that is used on the 180 and 185 which has a much higher GW. It might be overkill.

The cable attach point is a metal plate that bolts in to the gear attach point. It can be purchased from Aero Ski in Broten MN. Contact Troy at 320-346-2285. I think they were about 100 dollars a set. This system works just fine although I have heard from some Alaska types that the attach point on the engine cowling may be better. I am not sure of the logic here but that is what I have heard. No one makes dollys commercially anymore that I am aware of, so each set is pretty much a custom deal. The gent who made mine will make a set for others. They will run about 550 to 600 dollars. PM me for his contact info if you are interested.

Bill

[mod cessna]

change

Bill Rusk
PostPosted: Thu Feb 14, 2008 1:33 am Post subject:
Mark

Sorry I did not respond to your questions.

The Federal 3500 ski is not approved on the TCDS for the 170. As a result you will need to get the FAA to sign off on it. This could be a problem. It is also a much larger ski that is used on the 180 and 185 which has a much higher GW. It might be overkill.

The cable attach point is a metal plate that bolts in to the gear attach point. It can be purchased from Aero Ski in Broten MN. Contact Troy at 320-346-2285. I think they were about 100 dollars a set. This system works just fine although I have heard from some Alaska types that the attach point on the engine cowling may be better. I am not sure of the logic here but that is what I have heard. No one makes dollys commercially anymore that I am aware of, so each set is pretty much a custom deal. The gent who made mine will make a set for others. They will run about 550 to 600 dollars. PM me for his contact info if you are interested.

Bill

208. Two skis
(a) Federal A-2500 according to Cessna dwg. 53 lb. (+16) (+16) (+16)
No. 0541102 or Federal Instln. dwg. No. 11R170
*(b) Call S-5 per Call Aircraft dwg. No. 262 71 lb. (+18) (+18) (+18)
(not eligible with Items 201(b) and 202(a) or (c)
installed)
*(c) Federal A-2500A Federal Instln. dwg. 11R170 Use actual weight change
*(d) Federal A-3500 Federal Instln. dwg. 11R170 Use actual weight

The Federal 3500 is listed on the 170 TC. Item 208 (d).

The other ski attach method does not attach to the cowling. The spring, or bungee attaches, to a tab bolted to the upper engine mount attach structure. The forward check cable attaches to a tab on the lower engine mount bolt. The aft check cable attaches to a tab mounted on the lower fuse, where the back seat attaches to the side skin. This is much better then the gear leg clamp set up. There have been numerous cases where the clamp gets pulled loose causing the ski to rotate in the air. Most mechanics will not even install skis on an airplane with the gear leg clamp. Landis also came out with the AD that required their bungee and forward check to be relocated off the gear leg bracket.

[Bill Rusk]

Thank you for the correction.
The bracket that I have bolts into the gear leg attach point and also clamps to the gear leg. I don't see how it could possibly fail without tearing the gear leg off but I'll be the first to admit that my ski knowledge and experience is limited. If there was, or is, a bracket that only clamped to the leg I could see how that could be a problem.

http://i25.photobucket.com/albums/c59/b ... ket001.jpg

http://i25.photobucket.com/albums/c59/b ... ket002.jpg

http://i25.photobucket.com/albums/c59/b ... ket003.jpg

Bill

[mod cessna]

You are right. IT is difficult for it to slide down or come off. The bracket is still used by some but mostly for the rear check cable only. I think it works ok for just toolin around but when you start heavy ski flying where you may be jumping snow berms glaciers and everything else you need all you can get. The other reason, for the other mounting locations, is the improved geometry in bungee angles and check cable angles. Less likely for the ski to go over center.

[marathonrunner]

I realize this is an old thread however, I have always flown straight skis and now find that in the Anchorage area it is probably advantageous to have hydralic wheel skis. On the TCDS both the Federal 2500 and 3500 are listed but not the 3000? Is there a reason for this? I would think if not then a field approval could remedy the situation.

Are there other skis out there now that anyone knows of that would be good candidates for retractable. I know there was a Fli Lite ski but they are no manufactured and I really do not want to go with the wheel down through the ski option. I think Schneider had those and probably others.

Thanks and even though straight skis are probably the best sometimes you hae to compromise just as with amphibious floats over straight floats.

[futr_alaskaflyer]

Airglas Inc. in Anchorage was working on getting their new GLH3000 hydraulic wheel skis certified for the Cessna 170 on a STC.

Not sure if they've accomplished that yet. For a brand new hydraulic wheel ski the price actually wasn't too eye-watering.

Hmmm. "Not too eye-watering" at $12900.00 plus the pump if needed and installation. It's amazing how aircraft ownership can make you say outrageous things like that. Everything is relative I guess