# Flex Shaft Chute Control



## dbert (Aug 25, 2013)

I'm just wondering why this isnt more popular. My only guess would be added costs. I know many cheap weed eaters use them so it cant be super expensive. I noticed this setup on an older Husqvarna after looking at a photo in another thread. I really think this looks much beter than trying to place universal joints around the obsticles between the crank and the chute.








Just food for thought. Thats all.
We use flex shafts to operate some flight controls on aircraft I work on.
They are not the best thing ever, but for this application it seems perfect.
Elliott Manufacturing
Del


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## CarlB (Jan 2, 2011)

im figuring that if water get in it you will be SOL in sub 32 temps.


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## dbert (Aug 25, 2013)

CarlB said:


> im figuring that if water get in it you will be SOL in sub 32 temps.


Understood and possibly true. Similar to the issues with the Ariens push/pull chute deflector cable we’ve seen discussed here. Unfortunately I don’t know of any operator of these Husqvarna machines to know if it’s an issue. 
Moisture ingress into the flex shafts has been a huge battle for us on the aircraft that use these. They take off on a wet runway and completely saturate the outside of the flexshafts that run along the trailing edge of the wings. Then they climb to cruise altitude where it’s butt cold. If it can fail it will in this setup. The aircraft manufacture has tried a variety of gaskets, o-rings and flexible seals over the years but eventually settled on a type of copper crush washer to seal the ends of the flex shaft. Properly torqued they do ok. The proper type and amount of grease is also a factor. 
I’m not sure how much torque a typical human can apply to a hand crank, but I believe it would really have to be significantly frozen to lock up the twisting moment. Imagine big ice blocks forming around your current chute control rod/snow blower. How much ice would it take before you couldn’t crank it and bust a "greased" rotating rod free?


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## Blue Hill (Mar 31, 2013)

CarlB said:


> im figuring that if water get in it you will be SOL in sub 32 temps.


I offer for your consideration, speedometer cables on cars and trucks. I don't suppose they still use them with modern electronics, but for a lot of years they did the job, through heat, cold, wet and dry, relying mostly, I think, on good lubrication to keep the water out. As I recall, the only one I ever had to replace was on a 1953 Chev.
Just sayin' 
Larry


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## dbert (Aug 25, 2013)

They are very similar in construction to the old speedometer cable. Just bigger. The wire wound core is the same as the flexible extensions you can get for your ratchet/socket extension so they can handle some torque. 
I was just surprised when I saw it on the older Husqvarna that it wasn't used more often for chute rotation like they had done. It just seems like a very practical place for one.


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## Blue Hill (Mar 31, 2013)

I totally agree Del.


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## dbert (Aug 25, 2013)

I'm laughing thinking about all the aircraft mechanics I work with hearing me promote the use of flex shafts. They have heard nothing but rants from me for the 20 years now we have been operating a certain type aircraft with them installed. Using them to drive huge flap panels into various positions on a commercial aircraft doing a couple hundred knots was a mistake. Rotating the worm gear on a snow blower chute however seems perfect.


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## db9938 (Nov 17, 2013)

I would guess that rotating a worm gear, that had a shield, would all but take any chance of water infiltration out of the mix. I would make sure that there was a grease fitting, on the up end side, so that you could push water down and out. 

A push-pull cable would be more susceptible, although Honda's and Yami's both have rubber boots that enclose the cable to the shield. 

On another, sacrilegious approach to the purists, this would allow you to remotely locate an electric motor in the dash and out of the elements. Just extend the cables all the way to the dash.


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## micah68kj (Oct 8, 2011)

dbert said:


> I'm laughing thinking about all the aircraft mechanics I work with hearing me promote the use of flex shafts. They have heard nothing but rants from me for the 20 years now we have been operating a certain type aircraft with them installed. Using them to drive huge flap panels into various positions on a commercial aircraft doing a couple hundred knots was a mistake. Rotating the worm gear on a snow blower chute however seems perfect.


This'*really* boosts my already shakey confidence in flying. Thanks a bunch Del.:


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## dbert (Aug 25, 2013)

You are ok cruising down the road on two wheels with no enclosure or seat belt but afraid of flying?
I cant tell you how many times this system has failed in the last month (too many) yet alone the last 20 years. I can assure there has never been any accident related to this system. They typically have to land at a higher speed then they would otherwise, but as I said, the good news is there has never been any accidents involved. I'm not saying it's not a safety concern, everything is. It is a reliability issue for sure and too often the reason for cancellations and delays. Flying has to be safer than blowing snow Joe and I just wanted to reassure you it's still safe to fly.


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