Ski Installation

sort of hit on it

You guys are pretty much saying what I am. First off to go on skis for what sounds like the first time, an a&p needs to do the paperwork ie logbook entry, field approval or stc. Then a weight and balance has to be completed with an a&p # on the bottom. My point was that you have to have an a&p do that stuff, why not have him do or help with the install at least the first time. (As compared to option b: which is get you advice from a CHATBOARD ON THE INTERNET!)
Also for the mauleguy, a machinist is not governed by faa regulations I'm guessing. I am quite sure you can "annual" your expiramental. I am also quite sure you can't do almost anything LEGALLY on a certified airplane. That's the whole point. Sorry I was mistaken. Didn't think you guys weren't looking to break the law and post it on the internet........
In that case do what you want. Put the damn skis on however looks right to you. Definitely NO NEED to check the angles per the 43.13 since you aren't even trying to be legal. Do what "looks right" to you.

This is not an FAA sanctioned web site so to glean information about a subject that happens to deal with aircraft is what I am after. The legal part of it really is not what I am after.

I know some are getting the point I am trying to make. Enough said from me on this.

Greg

An interesting thread.

Jon B made the point that the mechanics in the Canadian incident didn't properly install the skis----but Jon, you make the ASSUMPTION that these skis were installed THIS TIME by a mechanic. Nothing I saw in that report suggested the skis weren't possibly installed by the pilot, which is pretty common in ski country. Could it be possible that these skis were INITIALLY installed by a mechanic several years ago, then subsequently installed by pilots, who weren't aware of the AD?

I am VERY sensitive to check cables and limit cables on ski installations. I see a LOT of Cubs, Huskys, Scouts, etc, with the forward cables attached to the forward gear attach point. Personally, I think that's a recipe for disaster. As Luke says, have a ski come up on you once, and you'll be a believer. If one were to go over on you, you would truly be screwed. I like forward cables attached to the engine mount bolts, NOT to the gear bolts. Look at the geometry of the gear, and my reasoning should be apparent.

I've had a ski come up on me when a rear limit cable broke, as Luke described. It was ugly, but manageable. One going over would be REALLY bad.

Greg, I don't think the "find an A & P" comments here warrant turning this into a rant and rave session. If you choose not to follow the regs, or you have an experimental, governed by a SLIGHTLY different set of rules, so be it. Nevertheless, the first post on here struck me as being from someone asking VERY basic questions, NOT someone who is a really savvy mechanic. The internet can be tricky in that regard--the fellow may be a GREAT mechanic.

Nevertheless, there are lots of ways to get hurt with skis, both in the installation, and operation.

I'm with you, I wouldn't have a mechanic who only works on B-747s install a set of skis for me either. That wasn't the point the others made either. There's no magic to an A & P certificate, just as there's no magic to a pilot certificate.

The key is to do these things safely, and finding a KNOWLEDGEABLE mechanic is always a great idea when working on an unknown evolution.

MTV

It's snowing here in the northeast. I don't know if I should put my skis on or shoot myself. :roll:

Tim

Tim,

If you do choose to shoot yourself, be sure that you get a certified weapons instructor to show you the proper method complete with the correct angles and attach points etc. so that you do not botch it.

Otherwise let's all just sit back, have a collective beer, and watch someone else huff and puff and change their cub to skis!

MTV

I'd REALLY like to hear more about your different attach points for the forward cables, I've never seen that and never heard of it either; though it makes sense when you look at the Cessna attach points; obviously though on the Cub you'd have to "modify" the cowling a good deal, and if you lost either cable then seems like it could be a very expensive cowl repair/replacement? Let me hear more about that method if you could, as well as the benefits that you have seen from your experience doing it that way?
Thanks!

RB

There's a cub here that has its safety cable attached to the lower engine mount lug on the boot cowl. The bracket looks like a FAD lifting eye with a small slit in the bottom cowl to poke thru.

I see alot of installations with the safety cable and bungees hooked to the same attach fitting. 43.13 and the Federal installation drawing say not to do that yet alot of people still do.

Red Baron,

I've had initial installations done on both Cubs and Huskys, several, and always insisted that they be done with the cables attached to the lower engine mounts. The FAA FSDO guys have always commented during the inspection for the field approval that that looks like a lot better pull angle.

I didn't invent it, and I can't take credit for it. It only requires just a little cutting of sheet metal (a 1 inch by 1.5 inch) removal on the cowl. The pull angles are FAR better from that point.

Look at the angles in that Cessna accident report, and then compare the angle of a Cub's ski cables when they're attached to the gear fitting. Granted, the Cessna is a lot faster airplane, but I'm not sure you couldn't get there with the Cub.

Put one up on a hoist sometime, and see what it takes to pull the ski over center--nose down.....

MTV

Well the hell has already been raised, so I might as well throw a "chunk" under it.
The original poster asked for "..need some help from step one to completion."
Now, when I read that, I assume the guy knows absolutely nothing about installing skis on a plane. (I think other folks did also.) I thank that would be a safe assumption. That's why the advise to get an A/P was given. Not only is he ignorant about installing skis, he may be asking us to help him break a law.
If a Licensed Mechanic gave advise on this site, to an owner to "maybe" break a law, He would probably be liable. If you don't think this is true, ask the guy who posted the pic of the rusted Piper fork that got a call from the FAA. One of our fine friends here, didn't let his shirttail hit his butt until he forwarded that pic to the local FSDO. Needless to say, he doesn't post any more pics or give much advise either.
Second point.
Contrary to popular opinion, Mechanics are not here just to provide FREE advice to owners on how to work on their plane. The information asked for, was "earned" by the mechanic. It cost him money and time. Another member on here called it "Intellectual Property." If he gives it free, its out of the goodness of his heart.
Go to your local Chevrolet mechanic and ask him to tell you how to install a new distributor in your pickup. You think he will tell you? I doubt it.
Third point.
If you think that the Mechanics on here haven't given Tons of free advice, you need to go read the archives. Your wrong. I like to think that I have helped a few members with problems in the past. I have spent hours researching ADs, TCDS, Service Bulletins, prior approved 337s, etc for people that I will probably never meet. I did it because I wanted to.
That will now stop.

Fourth point.
Damn, 4 times so far, I've agreed with Mike. (I'm keeping track!) AC 43-13 shows the forward cables attached to the front gear bolt. Wrong! Attach them to the bottom engine mount bolt. Get a couple longer engine mount bolts and cut a little aluminum from the lower cowl. Read Mikes post for the reasons to do so.
Fifth point.
I just violated my Second point, by giving FREE advice! Just ignore the Fourth point. I didn't mean it.


Later, gotta go, Michael Savage is on the radio.

T.J. said:

Attach them to the bottom engine mount bolt. Get a couple longer engine mount bolts and cut a little aluminum from the lower cowl. Read Mikes post for the reasons to do so.

Click to expand...

I gotta look into that TJ. Never seen it done around here before, but I'm just a flatlander so don't know too much. thanks for the free advice tho.

Are we talking the safety cable or the spring cable??
Brian

Brian:
Both. I've got my old beater Cub in the hangar now, trying to make it half way presentable. Believe it or not, I actually took some of the duct tape off and replaced it with genuine STITS FABRIC! I'll try to take a pic of the fitting tomorrow.
No big deal, upsidedown "T" fabricated from steel of your choice. Tail of "T" has hole for engine mount mount bolt, crossbar has two holes, one for bungee and one for safety cable. Also see AC 43-13-2A page 36, Figure 5.3.
As stated above, much more reasonable angle.
Oh yea, almost forgot, in reference to the above thread, be sure and get your local A/P to approve this mod before you install it!

WOW guess better not ask such a generic question. I have put skis on before so it wasnt the first time. Although was first time on a cub. Was looking for more tips i guess, for example some that think attaching front cable to gear v.s. engine mount. Heard of folks lifting by wing and others manufacturing a mount to lift gear equally. Plane had been on skis before so weight and balance has been done. etc... Guess i started something now. Also replaced bungees with the spring type (and yes have an stc) with that.

S2D said:

T.J. said:

Attach them to the bottom engine mount bolt. Get a couple longer engine mount bolts and cut a little aluminum from the lower cowl. Read Mikes post for the reasons to do so.

Click to expand...

I gotta look into that TJ. Never seen it done around here before, but I'm just a flatlander so don't know too much. thanks for the free advice tho.

Are we talking the safety cable or the spring cable??
Brian

Click to expand...

I, too think this attachment has a great deal of merit. However, the installation drawing from Aero-Ski shows the rigging bolted to the forward gear attachment for the Champ. What's the likelihood of getting a deviation or field approval to change it? The feds may know something is logical, safer and mo' better but that doesn't mean they'll approve it!

Jon B.

Jon,

I don't think you'd have any trouble with getting that deviation approved by the Minneapolis FSDO. They seem like one of the more reasonable outfits around, and they understand skis.

MTV

I have an experimental Bushmaster/Producer type airplane. Built some skis for it a few years ago and have used them when we've had good ski conditions here in the Valley. They have worked pretty well and no problems. Did give some thought about the what if's if the cables and bungee system should fail and alow the ski to rotate. I know it would not be a good situation. After reading trough the info on the 185 deal, I don't know if I will ever put them back on!!! Who would of thought that the engine could be jerked from the mount!!!

I'm wondering if this flying is very safe.

Flying is absolutely safe. We haven't left one up there yet....Your success at landings may vary a bit, however.

Nevertheless, it beats drooling in your pablum as a finish....

Skis RARELY go over, and probably never if properly installed and maintained.

This is part of the point of the mechanics on this thread's argument: Do it right!! And, while there are different ways to get there, its' always good to consult with an expert.

MTV

http://www.supercub.org/photopost/showphoto.php?photo=14176&size=big&cat=509

forward ski tabs