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dead mans steering

May 17 2006 at 8:11 AM
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wh  (no login)

 
The Ice Flyer design has a lot of things going for it safety wise but it still has one safety problem that seems to be there sometimes and sometimes not.

Many years ago, I left a IF parked (with only the runner parking brake) and the wind switched 180 degrees in a big gust, kicked off the brake and the boat took off on its own. This config had the sail way back from what it is now (ie, the boat was not balanced well).

One time landsailing, I left a boat just sitting with no parking brakes and a gust came up and it took off. This config had the sail more raked forward (ie, balanced better) and had a conventional front wheel arrangement where the tire contact point was behind the front fork projection to the ground. However, another time landsailing, I was doing high G force "S" turns and was leaned way over from one turn and didnt lean the oposite diretion in the next turn (and no seat belts) and fell out. The boat just turned into the wind and stopped. This config also had the good sail balance but the front tire contact point was in front of the fork projection angle to ground (which is supposed to be wrong because it is unstable but that may have been why the boat stopped). Even though this config is supposed to be unstable, it feels fine out sailing probably because my front tire is fairly square and with the 45 or so fork angle, it must lift the front end slightly to turn the boat so with the weight in the boat, it tends to force the steering straight ahead but without the weight (ie, no pilot), the instability may be what turned the steering and made the boat stop???

Ive also seen a few times where people just left boats sitting on the ice without any brake mechanism at all and the boats fortanetly just rounded up into the wind and stopped.

So Im not sure what has caused the boats to either take off or not but I do know that if you force the steering over to one direction, the boat will just find a balance point in the wind and sit there rocking back and forth as the wind direction changes. At the worst, the boat will go in a circle.

The IF web site hopefully has plenty of warnings about the possibility of this happening and also that people properly park the boat (by lashing the steering skewed to one side and also using the runner parking brake - the runner parking brake is NOT enough). But I think the design also really needs some sort of dead mans steering system so that if the pilot were ever tossed out of the boat, the steering would get skewed to one side and it would make sure that the boat did not go anywhere. The boat might go in a circle and come back at you which caries the risk of getting hit by your own boat but your first safety concern must be for others.

Anyhow, this is something Im working on and any ideas on this would be appreciated. Note that if you show your ideas, they become public property. If you have a great idea and want to patent it, than you should keep it private. But Im hoping for some good idea that is public and free for anyone to use.

 
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wh
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Re: dead mans steering

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June 2 2006, 11:43 AM 

Here is a first try at a dead mans steering: http://groups.msn.com/ICEFLYERPictureForum/shoebox.msnw

After thinking about all sorts of fairly complicated contraptions, here is the first dead mans steering I made. It is simply a spring from the base of the pedal to the steering control arm. From the pictures, you can see that when the pedal is put all the way forward, the spring is longer and when the pedal is back, the spring is shorter. The "gain" of the spring tension can be adjusted by sliding the spring attachement on the control bar.

It puts a constant pull on the steering to one side which is a down side but on the possitive side, it is very simple and you dont need to mess with hooking things to your body, ect or have ropes and bungie cords running to different places. I also like that I dont have to change anything going from the ice boat to land sailing versions. Springs wear out which is another negative.

We pushed the boat around in a parking lot and with a 11 year old 100 pounder in the boat, it did have a bias to pull to one side. However, even with no pilot in place, it did not have enough spring force to jam the steering completely over to one side. But if the steering did make it over to one side, it would stay there. It probbaly needs a higher tension spring than was used in the first proto. The pedals were not uncomfortable with the bias to one side but we also probably needed more tension.

Hopefully it will get some testing this summer landsailing. One main thing is to make sure the change does not create more problems than it corrects.

Note: its not clear that there is a significant problem with this in the first place and the Ice Flyer is probably no worse than Ice Boats in general. However, in order to feel "safe" about keeping up the ice flyer web site and plans, I think something on this needs to be on the web site identifying a potential safety risk and proposing some sort of solution "at your own risk".

 
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Anonymous
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dead man steering idea

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October 27 2009, 10:37 AM 

what about pretensioning the spring very hard and locking it via a pin.
tie the pin to your vest and when you go overboard the pin releases the spring which in turn rotates the front wheel

 
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