steering head angles

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US306
US306
55 posts
55 posts
28 Dec 2012 12:24pm
the head bearring is free as a bird, works great but the problem still exsists, that the 30 degree lay over design, in a critical hike angle, the front wheel is so flat to the ground that you can't turn off wind unless you dump the sheet get down past the critical angle and then turn off wind. Or stay below that critical angle.. all steering setups have a critical angle. I feel the higher the angle above horizonal, the higher the critical angle and the less turn overs cause by head angle design. head angle at 30 degree has a shallower critical angle. I've noticed that the big boats seen to have higher head angles. Is there something I'm missing..somebody prove me wrong, cause there are some aspect of the 30 deg angle that I like, but I don't like stuffing it at speed. Burt
US306
US306
55 posts
55 posts
28 Dec 2012 12:35pm
steering head angles posted on wrong thread, check out the welcome nalsa menbers. or maybe someone can get me straighten out.
landyacht
landyacht
WA
5921 posts
WA, 5921 posts
28 Dec 2012 7:26pm
very interesting. can you get us a photo of it sitting on the ground? also is the chassis behind the steering set up really low ,with a flexible set up or suspension?. from what your describing ,the problem should be turning upwind
US306
US306
55 posts
55 posts
29 Dec 2012 5:00am
Good morning Paul, thanks for the reply. My poblem is, my enability to to type on the forum, what I'm seeing in my head. Also because of my limited computer skills I havn't figured out how to post pictures on the forum, but i'm working on that. The us minis are open frame units, so a high speed tip over is of great concern to me, my 71 year ole body isn't going to do well in the event of a nasty stuffing, so that is why the head angle concern. the critical angle I've talked about is the angle of the rear axel compaired to the ground just before a tip over, this angle translates to the angle of the head (kingpin) and front tire being in a perpindicular plane to the rear axel. So at the critical angle, the 30 degree angle will allow more flop than a more virtical angle, this flop wants to return to vertical under pressure and the tire leading edge has too pick the front up to get the angle of turning started, lots more pressure on the steering bar is required to get things going right, and if you are not right with it, you will end up in trouble. that is why I'm concerned about the (30 degree angle) that is in use. Like I have said there is some things about that setup I like, pros and cons. I'm trying to get a computer work up to show the tire layover at different degrees from virtical to the 30 degrees.. and this would help everyone make a choice as to front kingpin set up....
cheers






Test pilot 1
Test pilot 1
WA
1430 posts
WA, 1430 posts
29 Dec 2012 11:02am
Burton we dont usually have great problems tipping over as we use seat belts.
Advantages of seat belts:- They stop you falling out. You can leverage yourself against them.
This can increase your confidence to try that little bit harder
I don't know if this helps you
sn
sn
WA
2775 posts
sn sn
WA, 2775 posts
29 Dec 2012 4:07pm
how about fitting a 4 point harness- similar to those a race car uses.
With a 4 point harness you can still slide forewards to put weight over the front wheel- but wont be able to lean side to side as much.

If you do tip or spin out real fast, you wont get thrown out of the landyacht.

When I get my camera working again I will put up a pic. of our "Chook Chaser" with its harness and ankle straps.

stephen
Test pilot 1
Test pilot 1
WA
1430 posts
WA, 1430 posts
30 Dec 2012 12:47am
In strong winds, I like to be able to get my weight over the upwind wheel and a car racing style seat belt would prevent me doing this
US306
US306
55 posts
55 posts
30 Dec 2012 4:35am
seat belts? I have allways worn them, on the mini ive been trapped in super good and with heal hanger, thats not the problem, it's if a mast breaks and I have to rub my nose on the playa. the posts that I was talking about, had to do with a possable glitch in the 30 degree layover steering design, I want good design so I don't have to fret If I'm building something that problemmatic. there are allways ticks in design, some just have more ticks than others. with the yatchs that I've built they have been good preformers and have seen their share of steep tipover type hikes and I have aways been able to steer off down wind. I like being in a steep controlled hick and blasting down wind, you know, just playing around. I was good at it. I buy a Promo, and the first moderate hike, over I go, I won't tell you what I said. I say to my self that should not have happened. I now question the design and I know that their are many others that feel the same way. I was looking for some one to defend the layover design, cheers Burt..
Hiko
Hiko
1229 posts
1229 posts
30 Dec 2012 5:53pm
This is interesting as Paul said.
I think I know what you are saying but cant say I have experienced it maybe it is because I dont try to bear away when heeled.
The only yachts I have sailed have all had the 30 degree layover
The venues I sail on [beaches and car parks] there is not a lot of room to bear away and heeling is controlled [by me anyway ] with the mainsheet.
Those who have more room may well do something different.
I look forward to others comments
oldMXer
oldMXer
130 posts
130 posts
30 Dec 2012 11:46pm
I do it with my minis when i have the area. Built with 30 degree layover, but running non standard sized wheels. Wonder if wheel size is a factor. It is probably the most exciting and fun manuever I perform when conditions allow it, almost as smooth and solid feeling as flying (or the first drop on a roller coaster). Love it!!
wokelliott
wokelliott
WA
179 posts
WA, 179 posts
31 Dec 2012 11:54pm
Hi Burt, I dragged my mini out today witha 30 degree layover and had a look at the effect when you heel. Normally the steering shaft (kingpin) lines up with the point where the wheel touches ground and steering is balanced. However, when you heel over the point where the wheel touches ground becomes further forward of a line down the kingpin and it becomes harder to turn off downwind as you noted. To turn upwind becomes much easier as you heel further and becomers an almost automatic correction to heeling . The only steering which will not cause a problem will be one with a vertical kingpin and no layover, but that produces another problem as the wheel tries to skip sideways in a turn. I find the layover type is better, you will have to make your own decision on the angle as there is only a compromise angle available.

Like a previous reply said, I would turn into the wind to control heel... not turn offwind. When you lift a windward wheel beyond a certain point the combined effect of CG shifting windward and wind pressure on the sail will roll you over regardless of the steering layover angle and only easing the sheet will save your neck. When sailing my radio yacht and get hit with a gust I let the sails off slightly as she accelerates rather than heel, then bring them in when gust has eased. Hope the above has some sensible suggestions.

Have a great 2013 to all sailors....wok
wokelliott
wokelliott
WA
179 posts
WA, 179 posts
1 Jan 2013 12:00am
Little correction to the other reply.... when you heel the CG moves leeward not windward.
US306
US306
55 posts
55 posts
1 Jan 2013 1:30am
Thanks Wok, with the type of heeling/hike I was dealing with was a gust slaming..that is why I spoke about the critical angle which is associated with the degree of head angle from vertical to 30 degree. I feel the higher or steeper the head angle the higher the heel before the point of no return. with the minis everthing gets more critical quicker..what you abserved is what I saw in the promo steering, when sailing the promo I have to keep the critical angle more shallow, the way my mini was set up allowed for a higher critical angle and at the time I was very used to that high angle but quickly found out with the promo too keep the heel lower...thanks for the inport! may the force be with one and all in 2013...cheers Burt
kiwi307
kiwi307
488 posts
488 posts
28 Jan 2013 2:18pm
without photo or drawing it is pretty difficult to be too positive, but what you describe is exactly what I found in the early days of "layover" steering before I took the extraordinary effort to make sure that the extended axis of the steering pivot lined EXACTLY on the centre of the tyre patch.
landyacht
landyacht
WA
5921 posts
WA, 5921 posts
28 Jan 2013 8:59pm
kiwi307 said...
without photo or drawing it is pretty difficult to be too positive, but what you describe is exactly what I found in the early days of "layover" steering before I took the extraordinary effort to make sure that the extended axis of the steering pivot lined EXACTLY on the centre of the tyre patch.


welcome back kiwi307, glad to hear somebody else aying that the contact patch alignment needs to spot on
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